One whole-body MRI could replace multiple cancer scans(pharmatimes.com)
pharmatimes.com
One whole-body MRI could replace multiple cancer scans
http://www.pharmatimes.com/news/one_whole-body_mri_could_replace_multiple_cancer_scans_1287814
238 comments
Dentists don't have any trouble taking regular full-mouth x-rays. Maybe this is because this translates into money for each problem found.
In the same way, skin doctors take photos of body moles to see if any changes occur between visits.
I think internal doctors should start viewing this as inevitable.
Then up-front develop "watchful waiting" plans that over the course of time and several scans chase down any suspicious changes.
In the same way, skin doctors take photos of body moles to see if any changes occur between visits.
I think internal doctors should start viewing this as inevitable.
Then up-front develop "watchful waiting" plans that over the course of time and several scans chase down any suspicious changes.
The use case I can see is a healthy-before/after-sick... all those benign growths you're worried about seeing, will not change between scans. What will change/grow/shrink? Things you might might want to look at as causes of your illness.
Ignorance is bliss until you miss that easily removed tumor... etc and you are stage 3 going for chemo, or a brain anurism...
Ignorance is bliss until you miss that easily removed tumor... etc and you are stage 3 going for chemo, or a brain anurism...
I always found this approach strange. It's like closing your eyes and pretending you don't see parts of the patient's body.
Wouldn't you compare back to an original/baseline scan, making it easy to ignore anomalies?
This sounds to me like doing a full workup on blood chemistry. Individuals vary so much that you can get false positives.
Wouldn't it be more useful as a baseline? Scan once and store it, then scan every few years and compare. If any of the "anomalies" has grown or new ones have appeared between scans, then they might be worth a second look?
Wouldn't it be more useful as a baseline? Scan once and store it, then scan every few years and compare. If any of the "anomalies" has grown or new ones have appeared between scans, then they might be worth a second look?
Some of the comments here don't touch on the practical limitations of this, but here's one — I'm at a 1400+ bed top-10 US academic medical center, and even our outpatient MRI machines book patients until near-midnight because the scans take so long. I'm not sure if we even have the imaging capacity at this point to be scanning healthy people.
This!
I got up at 4am to run scans in grad school because the even the research scanners were booked solid, never mind the clinical ones. Scanners are really expensive: the machine costs a lot, it needs fairly particular conditions (shielded room, cryogens), and trained operators and analysts.
There's maybe a market for fleecing the extremely wealthy into undergoing MRI fishing expeditions, but you'd have to charge a fortune if you're going to buy scanners to do it.
I got up at 4am to run scans in grad school because the even the research scanners were booked solid, never mind the clinical ones. Scanners are really expensive: the machine costs a lot, it needs fairly particular conditions (shielded room, cryogens), and trained operators and analysts.
There's maybe a market for fleecing the extremely wealthy into undergoing MRI fishing expeditions, but you'd have to charge a fortune if you're going to buy scanners to do it.
I work for a company that makes MRI machines. There is an industry wide push to reduce scan times. Even a 30 second or one minute reduction on scan time per protocol can translate into one or two more scans a day. Across a fleet of scanners, this can be millions of dollars a year in revenue.
There are hospitals that have switched brands of scanners over protocol times.
There are hospitals that have switched brands of scanners over protocol times.
I don't know if they are high enough quality for a full body scan, but there are MRI places literally in strip malls now. Cash price for a back scan is ~$350.
Nations like Japan, China are pushing MRI resolution and speed, along with lowering the costs. Particularly because the average people getting older, thus diagnostics will reduce the cost of healthcare on the long run, on the scale of these countries.
Getting a baseline is harder than it sounds.
In the case of blood chemistry that is caused by fluctuations due to time of day, time of month, season, what you recently ate and so one.
In the case of MRI the problem is that internal organs shift to the point that it is impossible to automatically compare. And a experienced doctor comparing the scan millimeter for millimeter takes hours and would be very expensive. Even just tracking the volume of a known tumor in the brain (that shifts very little) to track the effect of radiation is tedious, time consuming and error prone.
In the case of blood chemistry that is caused by fluctuations due to time of day, time of month, season, what you recently ate and so one.
In the case of MRI the problem is that internal organs shift to the point that it is impossible to automatically compare. And a experienced doctor comparing the scan millimeter for millimeter takes hours and would be very expensive. Even just tracking the volume of a known tumor in the brain (that shifts very little) to track the effect of radiation is tedious, time consuming and error prone.
> internal organs shift to the point that it is impossible to automatically compare
I didn't even know that is a thing, I just sorta assumed they stayed put.
I didn't even know that is a thing, I just sorta assumed they stayed put.
You are a wet squishy clump of really advanced bacteria trying their damned best to physically hold together, barely alive. Don’t expect much. Human politics is the literal definition of shipping the org chart.
When undergoing abdominal radiation treatment, patients are asked to stop breathing to keep organs at their place (and not radiate healthy tissue), but apparently that still isn't good enough: https://www.ncbi.nlm.nih.gov/pubmed/27773445
> internal organs shift to the point that it is impossible to automatically compare.
Seems like a good area to apply machine learning if we had enough data?
Seems like a good area to apply machine learning if we had enough data?
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MRI scanners can only barely do quantitative evaluations... between different scanners, and different scanning protocols, your body may look quite a bit different and it is hard to know exactly how much variability to attribute to inter-scanner differences.
There are whole studies done to try and quantify this, and it requires sending "human phantoms"- test subjects- around to different scanners, which requires you to physically take one subject around to several scanners operated by different people and stick them in there for a while. It's really involved.
There are whole studies done to try and quantify this, and it requires sending "human phantoms"- test subjects- around to different scanners, which requires you to physically take one subject around to several scanners operated by different people and stick them in there for a while. It's really involved.
Even if we can't reliably compare a time series of images today, wouldn't it be useful to start scanning now, for use as baselines in several years once the state of the art improves?
In the same way astronomers can make new discoveries by digitizing photographic plates from a century ago.
In the same way astronomers can make new discoveries by digitizing photographic plates from a century ago.
Nope. Really, it's a question of priorities.
Scanners cost a lot: ~4M for a 3T (the current 'standard') and much more for higher field strengths. We just got a 7T and, with all the trimmings (scanner, console, coils, the shielded room to hold it all, training, etc), it's in the $10-15M range.
As a result, time on these things is already in pretty high demand, even at facilities that are used only for research. The projects could be reprioritized, of course, but most of the on-going research is much less speculative than "someday, this can be training data for something."
It's not even clear to me that old MRI data will be particularly worthwhile. Photographic plates were, until recently, about as good as digital sensors. New MRIs are much, much better than old ones, and the tech will only improve more. Longitudinal data is useful in both fields, but for astronomy, there's no way to rewind time, so old plates are the only possible source for events from the past. We get new old people, however, every day!
Scanners cost a lot: ~4M for a 3T (the current 'standard') and much more for higher field strengths. We just got a 7T and, with all the trimmings (scanner, console, coils, the shielded room to hold it all, training, etc), it's in the $10-15M range.
As a result, time on these things is already in pretty high demand, even at facilities that are used only for research. The projects could be reprioritized, of course, but most of the on-going research is much less speculative than "someday, this can be training data for something."
It's not even clear to me that old MRI data will be particularly worthwhile. Photographic plates were, until recently, about as good as digital sensors. New MRIs are much, much better than old ones, and the tech will only improve more. Longitudinal data is useful in both fields, but for astronomy, there's no way to rewind time, so old plates are the only possible source for events from the past. We get new old people, however, every day!
> We just got a 7T
Where is that? Might be worth the trip in some cases.
Where is that? Might be worth the trip in some cases.
I'm in Montreal, but 7Ts are popping up all over, especially now that Siemen's Magnetom Terra got FDA approval.
I know Yale also has a 7T, as does the NIH, Stanford, and MGH (I think--it's somewhere in Boston). The University of Minnesota has THREE which is crazy.
I know Yale also has a 7T, as does the NIH, Stanford, and MGH (I think--it's somewhere in Boston). The University of Minnesota has THREE which is crazy.
Similarly, the doctor who discovered Prostate Specific Antigen regrets that is used to screen for prostate cancer because of its inaccuracy, questionable benefits and substantial harm created by biopsies and treatment of prostate cancer:
https://www.nytimes.com/2010/03/10/opinion/10Ablin.html
https://www.nytimes.com/2010/03/10/opinion/10Ablin.html
Off-topic, just spreading knowledge. Check out IsoPSA [1], which is a simple blood test procedure superior to PSA (unfortunately, not available in US, yet).
[1] https://www.cleveland-diagnostics.com/isopsa
[1] https://www.cleveland-diagnostics.com/isopsa
Why do doctors advocate less frequent scans when they see that frequent scans creates false positives? Can a metric be invented such that a doctor can make a solid decision "I'm 99% sure this wont kill you in two years" and leave the tumour alone?
We don’t advocate less frequent scans, we advocate targeted scans. Because the probability of a positive result being a false positive depends heavily on the population. In a population with a high baseline frequency, the probability of a positive being false is relatively low; in a population with a low baseline frequency, the likelihood of a positive being false is relatively high.
So, you don’t mammogram every person with a breast. You mammogram people with advanced age, genetic predisposition, etc. so as to select for a population with a reasonable baseline frequency. Various professional bodies and the USPTF put a lot of effort into determining what the optimal screening population is.
Clinical decision rules are an extremely active part of medical research. Trying to figure out a reasonable predictive model to say “definitely follow up on this” or “definitely don’t” is a huge field in medicine. For instance, in patients ≥35 years old with incidental pulmonary nodules on CT imaging, we have the Fleischner Guidelines for when and which follow-up is appropriate. But it required a number of prospective external validation studies in order to properly validate it, and it’s for one super specific population: under-35 incidental pulmonary nodule on non-cancer-screening CT. So, you can imagine how much work there is to be done for the other 10,000 kinds of incidentalomas.
So, you don’t mammogram every person with a breast. You mammogram people with advanced age, genetic predisposition, etc. so as to select for a population with a reasonable baseline frequency. Various professional bodies and the USPTF put a lot of effort into determining what the optimal screening population is.
Clinical decision rules are an extremely active part of medical research. Trying to figure out a reasonable predictive model to say “definitely follow up on this” or “definitely don’t” is a huge field in medicine. For instance, in patients ≥35 years old with incidental pulmonary nodules on CT imaging, we have the Fleischner Guidelines for when and which follow-up is appropriate. But it required a number of prospective external validation studies in order to properly validate it, and it’s for one super specific population: under-35 incidental pulmonary nodule on non-cancer-screening CT. So, you can imagine how much work there is to be done for the other 10,000 kinds of incidentalomas.
Sitting in the oncology dept right now with my wife who’s gaving complications from a tumor. I’d just be happy with peer reviews of radiology reports so fuckups don’t cost us three months of potential treatment.
I’m sitting bedside wading through pull requests for software installation scripts. How is it the opinions of folks on my team for a bullshit process get more scrutiny than a potentially life-altering assessment that requires expertise, a keen eye and sharp mind every time?
I’m sitting bedside wading through pull requests for software installation scripts. How is it the opinions of folks on my team for a bullshit process get more scrutiny than a potentially life-altering assessment that requires expertise, a keen eye and sharp mind every time?
Radiologist here. Sorry to hear about about your wife's complications. Most radiology departments do participate in a peer review process as part of internal quality assurance. Not every report is necessarily peer-reviewed, largely due to time constraints (radiologists can read hundreds of mammograms in a day), and not all modalities are required to participate (I believe mammography is optional).
Thank you. I think it would be an extremely difficult job, particularly with a high throughput demands. This series was abdominal and i guess i would expect to see some annotation indicating it was reviewed.
In this case we had a scan in Nov. that was marked clear. Scan in Feb that had an unsized spot noted as ‘possibly metastatic’ with a note that ‘in retrospect this focus was present in previous exam’. Oncologist explains lack of measurement as being too small to precisely ascertain. Then two weeks ago we have a scan report indicating (among other new disease) a 4cm mass that was ‘previously 2cm.’
People are guaranteed to make mistakes, and my issue is with the process...not the personnel.
In this case we had a scan in Nov. that was marked clear. Scan in Feb that had an unsized spot noted as ‘possibly metastatic’ with a note that ‘in retrospect this focus was present in previous exam’. Oncologist explains lack of measurement as being too small to precisely ascertain. Then two weeks ago we have a scan report indicating (among other new disease) a 4cm mass that was ‘previously 2cm.’
People are guaranteed to make mistakes, and my issue is with the process...not the personnel.
I've been there and recently, I hope you come through at least as well as we have. My understanding is at minimum several radiologists lay eyes on before you hear anything from any of them. P.S. My wife wife says she wishes you and your wife all the best.
Thank you so much for the well wishes, and please extend our gratitude to your better half as well. I never appreciated the role that the support of others plays in the healing process untill I saw it first hand. It gives my beautiful bride a source of strength and confidence that keeps her stress that much lower and her outlook that much brighter.
But doesn't this approach make it nigh impossible to catch people that don't fit the mold? It almost seems like it becomes a tautology, by not capturing the diseases in people you don't think have them, and only looking in people that you do think have them. And the only way to change the mold is for enough people to likely die that you reevaluate the model.
I am not a doctor, but I cannot fathom why a doctor would ever advocate against more data. Even if that doctor chooses to ignore it, at least let the patient utilize it as he sees fit. As someone who has regularly had to argue with doctors to get a test done, it is incredibly frustrating.
I am not a doctor, but I cannot fathom why a doctor would ever advocate against more data. Even if that doctor chooses to ignore it, at least let the patient utilize it as he sees fit. As someone who has regularly had to argue with doctors to get a test done, it is incredibly frustrating.
Well, that’s part of why there’s constant research into what risk factors / predictive factors are. These aren’t mutually exclusive activities.
“Data” implies something neutral. Nothing about lab tests is neutral. Without contextual information and studies on how to -interpret- a finding, it’s just potentially terrifying noise. And terror usually results in action. Poorly informed action is often harmful. So... we are trying to prevent harm to our patients.
We are earnestly working on all fronts to build the studies to better interpret these findings. But we just aren’t there yet.
“Data” implies something neutral. Nothing about lab tests is neutral. Without contextual information and studies on how to -interpret- a finding, it’s just potentially terrifying noise. And terror usually results in action. Poorly informed action is often harmful. So... we are trying to prevent harm to our patients.
We are earnestly working on all fronts to build the studies to better interpret these findings. But we just aren’t there yet.
For a rational agent the expected value of information is never negative. (Of course it can be less than the cost of the test.) If a system is treating it as negative, that's a problem to fix.
I'm reminded of a recent visit to a doctor who refused to say anything quantitative about a test. Sure, your average client knows little decision theory, but this doctor either didn't either or pretended not to follow. To make a good decision you need both probabilities and utilities; the doctor presumably best knows the former while the client best knows and cares about the latter, so they need to be able to communicate this way.
I'm reminded of a recent visit to a doctor who refused to say anything quantitative about a test. Sure, your average client knows little decision theory, but this doctor either didn't either or pretended not to follow. To make a good decision you need both probabilities and utilities; the doctor presumably best knows the former while the client best knows and cares about the latter, so they need to be able to communicate this way.
Cool, so your serum zorblaxian levels are 300 ng/L. The finding was incidental, so it’s jot tied to existing symptoms / clinical suspicion. It’s a molecule involved in the inflammatory cascade. We don’t know what diseases it’s associated with or not, nor what the change in probability of having the diseases it could be associated with are, not change in prognosis. But, you have a number which your local lab pegs at 1 standard deviation above the mean for the sample they calibrated their measurement technique on.
So, should we now do a work-up for every disease known to man with an inflammatory component? If you have one, if, every test - with their attendant complications and costs - for every disease you don’t have will have net negative effect on your health. You baseline have no symptoms or clinical suspicion for any of these (again, tautology or incidental finding), so the baseline probability is you actually have no disease at all, and this is a spurious value. So, what’s the advantage of this incidental finding?
So, should we now do a work-up for every disease known to man with an inflammatory component? If you have one, if, every test - with their attendant complications and costs - for every disease you don’t have will have net negative effect on your health. You baseline have no symptoms or clinical suspicion for any of these (again, tautology or incidental finding), so the baseline probability is you actually have no disease at all, and this is a spurious value. So, what’s the advantage of this incidental finding?
Framing it as a choice between "have a cookbook decision tree that's been validated by RCTs in exactly this context" and "do a lot of costly (in resources and side effects) followup tests to show we're doing everything we can" is an example of the irrationality that needs fixing. People are capable of actually reasoning with uncertainty when they care about outcomes. When it's you, personally, facing a decision in your life, you don't throw up your hands and say "It's too complicated to decide! There are no actuarial tables about exactly this situation!" Having to decide means having to make a bet. You can be a better or a worse gambler, but we're all gamblers. Medicine as a profession seems to want to pretend they're not, rather like "investors" pretend to be qualitatively different from "speculators".
It’s not “cookbook decision tree”, it’s “data from which to make meaningful inferences about this finding.” It would be nice if we always have that; with incidental findings, we often don’t.
Put it this way: my doctor ordered a test for me, got the results, and made a recommendation. I was ignorant of both the costs (of all sorts) beforehand and of the product of probability and utility on which he (implicitly and unavoidably unless irrationally) based the decision. He did make a meaningful inference from this data, as anyone must to make a decision; he just refused to help me, as a consultant instead of a master, to make my own.
> Cool, so your serum zorblaxian levels are 300 ng/L. The finding was incidental, so it’s jot tied to existing symptoms / clinical suspicion. It’s a molecule involved in the inflammatory cascade.
This isn't that hard. You look at it again in 6 months. And you ask "Did it go up? Did it go down? Is this just your baseline?" And you keep your eyes open a little more strongly for issues that might correlate.
And, you know what, I, the patient, am FAR more invested in keeping tabs on whether things are going right or wrong in my own body than any doctor.
This isn't that hard. You look at it again in 6 months. And you ask "Did it go up? Did it go down? Is this just your baseline?" And you keep your eyes open a little more strongly for issues that might correlate.
And, you know what, I, the patient, am FAR more invested in keeping tabs on whether things are going right or wrong in my own body than any doctor.
> And, you know what, I, the patient, am FAR more invested in keeping tabs on whether things are going right or wrong in my own body than any doctor.
As someone who has had to figure out his health on his own after multiple doctors have failed or many never even attempted to help, I cannot agree with this more.
As someone who has had to figure out his health on his own after multiple doctors have failed or many never even attempted to help, I cannot agree with this more.
We could do an autopsy on you right now if you want. How sure are you that you just stubbed your toe and it's not some highly metastasized cancer?
"Of course it can be less than the cost of the test." includes non-monetary costs. I thought this was clear since the benefit we're talking about is obviously not wholly monetary. (Or even mostly.)
I suppose you're right that the expected value of information, not including the acquisition costs, is never negative.
That feels like cheating though--this information isn't free.
My argument is that the expected value of this information, including acquisition costs, can very easily be negative, since you can't just "ignore" being dead. These costs are extremely large in my snarky autopsy suggestion, but dominate for whole-body MRIs + followups too. The catch is that the scan doesn't have huge benefits and the costs of the followups, while non-trivial, aren't exactly open-heart surgery either, so both are in the neighborhood of zero, except for the monetary expense, which will be crazy high.
That feels like cheating though--this information isn't free.
My argument is that the expected value of this information, including acquisition costs, can very easily be negative, since you can't just "ignore" being dead. These costs are extremely large in my snarky autopsy suggestion, but dominate for whole-body MRIs + followups too. The catch is that the scan doesn't have huge benefits and the costs of the followups, while non-trivial, aren't exactly open-heart surgery either, so both are in the neighborhood of zero, except for the monetary expense, which will be crazy high.
Yup, agreed! In fact I wouldn't have done the test mentioned above if I'd been better informed (an MRI with gadolinium contrast; I was only told the latter bit the day I showed up for it. There seems to be a bit of controversy about possible low-level health effects of this contrast agent, and considering I was very probably fine a priori, I think it was a mistake to do this. But it's kind of another thing to decide this on the spot after making an appointment.)
(To say nothing of the extra $1000 surprise bill...)
Anyway, what is raising my hackles doesn't seem rational in the same way. It seems to have the flavor of "when we look and see certain signs, our system too often takes stupid harmful costly actions on that information. Therefore, don't look!" It'd be reassuring to continue "This is a workaround to an admittedly irrational system while we have the following people researching better ways to improve." But that's not the sort of thing I've read.
(To say nothing of the extra $1000 surprise bill...)
Anyway, what is raising my hackles doesn't seem rational in the same way. It seems to have the flavor of "when we look and see certain signs, our system too often takes stupid harmful costly actions on that information. Therefore, don't look!" It'd be reassuring to continue "This is a workaround to an admittedly irrational system while we have the following people researching better ways to improve." But that's not the sort of thing I've read.
My hunch from reading these comments is that the doctors tend to be experienced and pragmatic, and their experience teaches them what tests matter and when. The problem with this though is they start to believe those tests are useless when they might not be.
It becomes more complicated when you consider doctors have limited time and resources and cannot spend too much time with any single patient, at least the way the US healthcare system is designed. I believe this is a large contributing factor for why they behave the way they do - it's how the system is designed. And it's why I have all but given up on doctors even trying to help me with my bizarre symptoms, where I have been accused of lying multiple times.
It becomes more complicated when you consider doctors have limited time and resources and cannot spend too much time with any single patient, at least the way the US healthcare system is designed. I believe this is a large contributing factor for why they behave the way they do - it's how the system is designed. And it's why I have all but given up on doctors even trying to help me with my bizarre symptoms, where I have been accused of lying multiple times.
Sympathies -- I've had some experience of that sort too. I'd have more sympathy with the doctors' side (it is a very difficult position) if they weren't set up as gatekeepers.
I understand it is not a black-and-white situation, and that data is obviously not perfect. And I certainly am not advocating that doctors should order a gamut of tests unnecessarily. But if there is any doubt, how likely is the added data to harm more than help? And I firmly believe the doctor should not fight the patient on a test unless there is a strong reason not to (apart from an obvious medical disorder such as Munchausen syndrome it is hard for me to think of a reason).
If the added data is noise, it can easily be ignored. If it's not noise, then you're lucky to have it. And figuring out whether or not it is noise is important, but you can't do that without the data.
But again, I am not a doctor, and how much bandwidth they have and where their priorities lie is not something I intimately understand. However something that has become blindingly obvious to me is that most doctors do not have a firm grasp of statistics, and will advocate for new drugs when the actual test results are borderline statistically insignificant and easily explained away by confounding factors (most obviously the placebo effect). Sadly not all trials are double-blind, something else I do not understand.
If the added data is noise, it can easily be ignored. If it's not noise, then you're lucky to have it. And figuring out whether or not it is noise is important, but you can't do that without the data.
But again, I am not a doctor, and how much bandwidth they have and where their priorities lie is not something I intimately understand. However something that has become blindingly obvious to me is that most doctors do not have a firm grasp of statistics, and will advocate for new drugs when the actual test results are borderline statistically insignificant and easily explained away by confounding factors (most obviously the placebo effect). Sadly not all trials are double-blind, something else I do not understand.
You can’t ignore the noise because we don’t know it’s noise. I know I’m failing to get that idea across, but I honestly don’t know how to articulate it better than I have been. I can tell you’re honestly trying to understand, and I feel the blame is likely on me as a communicator.
Possibly what I’ve failed to communicate is this:
MRI, CXR, etc are not images of the body. It’s not like getting a photograph of a liver and saying, at least we know this is or isn’t going on in the liver. They’re indirect measures of certain attributes of the body, such as tissue density, which we use - coupled with their medical information, and the mechanisms of likely diseases - to infer what’s happening. That’s why reading radiology is a medical specialty, and not something anyone with an anatomy background can do. (There’s a radiologist currently browsing the thread - he’s very welcome to correct me if I’m wrong about what radiology “is”.)
Because of this, every such finding has to be interpreted in a context, and studies tell us how.
Completely out of context findings aren’t a big problem if they’re completely unambiguous: hey, that bone is in two pieces and it should be in one.
What about the finding that isn’t, though? This is equivalent to not having any information on a test’s false positive / false negative rate, only now it’s open-ended to “every condition that could look like that thing” because the defining characteristic of an incidental finding is that it’s -incidental-. It’s not related to any symptoms. So what do I do with “every disease or non-disease process that could potentially look like a spot on the lung, without any accompanying symptoms of that disease”?
What I believe is the responsible answer is: “if I think the pre-test probability isn’t borderline zero, AND the post-test probability would change my course of treatment or diagnosis, order the test. If the pre-test probability is so low that any positive test result would be very likely to be a false positive and thus force me to act in a manner harmful to the patient, don’t order it - it shouldn’t be allowed to change the course of treatment. If the pre-test probability is already so high that any negative result is likely a false negative, don’t order it - it shouldn’t be allowed to change the course of treatment. Only order tests whose results should impact the course of diagnostics or treatment.” What do I do with findings that haven’t been studied in a given context, so I have no clue what their impact on the post-test probability of a diagnosis is? I don’t know. But “test just in case” isn’t the zero-risk option. There aren’t any zero consequence options.
Not every test is an RCT because grant funding agencies don’t provide the budget, plus or minus, many RCTs we’d like to do are unethical (if you have good reason to believe one course of therapy is superior to another, you don’t have the clinical uncertainty to ethically allow randomizing people into an inferior therapy), plus or minus many sub-populations are just too uncommon to build an RCT on without a gigantic budget that facilitates long collection periods across multiple institutions.
Possibly what I’ve failed to communicate is this:
MRI, CXR, etc are not images of the body. It’s not like getting a photograph of a liver and saying, at least we know this is or isn’t going on in the liver. They’re indirect measures of certain attributes of the body, such as tissue density, which we use - coupled with their medical information, and the mechanisms of likely diseases - to infer what’s happening. That’s why reading radiology is a medical specialty, and not something anyone with an anatomy background can do. (There’s a radiologist currently browsing the thread - he’s very welcome to correct me if I’m wrong about what radiology “is”.)
Because of this, every such finding has to be interpreted in a context, and studies tell us how.
Completely out of context findings aren’t a big problem if they’re completely unambiguous: hey, that bone is in two pieces and it should be in one.
What about the finding that isn’t, though? This is equivalent to not having any information on a test’s false positive / false negative rate, only now it’s open-ended to “every condition that could look like that thing” because the defining characteristic of an incidental finding is that it’s -incidental-. It’s not related to any symptoms. So what do I do with “every disease or non-disease process that could potentially look like a spot on the lung, without any accompanying symptoms of that disease”?
What I believe is the responsible answer is: “if I think the pre-test probability isn’t borderline zero, AND the post-test probability would change my course of treatment or diagnosis, order the test. If the pre-test probability is so low that any positive test result would be very likely to be a false positive and thus force me to act in a manner harmful to the patient, don’t order it - it shouldn’t be allowed to change the course of treatment. If the pre-test probability is already so high that any negative result is likely a false negative, don’t order it - it shouldn’t be allowed to change the course of treatment. Only order tests whose results should impact the course of diagnostics or treatment.” What do I do with findings that haven’t been studied in a given context, so I have no clue what their impact on the post-test probability of a diagnosis is? I don’t know. But “test just in case” isn’t the zero-risk option. There aren’t any zero consequence options.
Not every test is an RCT because grant funding agencies don’t provide the budget, plus or minus, many RCTs we’d like to do are unethical (if you have good reason to believe one course of therapy is superior to another, you don’t have the clinical uncertainty to ethically allow randomizing people into an inferior therapy), plus or minus many sub-populations are just too uncommon to build an RCT on without a gigantic budget that facilitates long collection periods across multiple institutions.
I imagine there is a lot of non-optimal decision making going on the patients side because of the emotional salience of cancer, and on the doctors side because of lawsuit risk.
Why is this an issue with testing rather than an issue with the conditions under which treatment is given?
In other words, ISTM the problem isn’t with a full-body scan per se. The problem happens if every little thing found gets treated or tested invasively.
In other words, ISTM the problem isn’t with a full-body scan per se. The problem happens if every little thing found gets treated or tested invasively.
Why can't a doctor see an anomaly and decide not to chase it down based on the same reasoning that they use to not scan for it? Is there some pointless legal trap related to malpractice where the only allowable "don't operate" decision happens when the doctor decides what to test for?
We had a medical student who had her abdomen scanned as part of teaching. They found a cystic looking thing on her pancreas. She ended up getting it excised - it was benign and would've never caused problems, but she had multiple complications and 2 months in hospital as a result of the surgery.
I think Doctors (I am one) definitely err on the side of overtreating in those uncertain situations. Just like politicians, it feels more caring to act than to not act.
If you MRI 1000 people and leave the vague results in the hands of a bunch of physicians, they will tend to be interventional. This will lead to a spate of overtreatment.
Ways around this would be to consent patients for watchful waiting in the case of uncertain lesions. Even so, telling people they have weird looking lumps that you're not going to treat will cause serious anxiety.
I think Doctors (I am one) definitely err on the side of overtreating in those uncertain situations. Just like politicians, it feels more caring to act than to not act.
If you MRI 1000 people and leave the vague results in the hands of a bunch of physicians, they will tend to be interventional. This will lead to a spate of overtreatment.
Ways around this would be to consent patients for watchful waiting in the case of uncertain lesions. Even so, telling people they have weird looking lumps that you're not going to treat will cause serious anxiety.
Why can't a doctor see an anomaly and decide not to chase it down based on the same reasoning that they use to not scan for it?
(1) Because we do not have the body of knowledge that tells us how to predict an anomaly is not worth pursuing. It would require a lot of major, expensive, long-term studies involving non- negligible chemical exposures in$ asymptomatic people in order to get a good idea of what the “healthy” anomaly looks like.
$ many of these MRIs require contrast material.
(2) Malpractice for a missed cancer in most states has an enormous lookback period and an automatic “doctor loses.” It doesn’t matter if the doc made a statistically appropriate call. So docs follow-up on anything but the most unambiguously benign lesions.
$ many of these MRIs require contrast material.
(2) Malpractice for a missed cancer in most states has an enormous lookback period and an automatic “doctor loses.” It doesn’t matter if the doc made a statistically appropriate call. So docs follow-up on anything but the most unambiguously benign lesions.
> statistically appropriate call.
but factually incorrect call is apparently OK, because they are treating "median person", and not the actual patient.
This has to do with money - and nothing else.
but factually incorrect call is apparently OK, because they are treating "median person", and not the actual patient.
This has to do with money - and nothing else.
No, it has to do with avoiding harm to patients. I don’t make one red cent more or less from sending someone to an MRI or not. I do care about wasteful testing that is more likely to stress out a patient and send them down a rabbit-hole of follow-up tests with potential complications and costs (to them), if there’s not a reasonable chance of an outweighing clinical benefit for them.
And of course we make statistical calls! When you’re deciding -prospectively- whether a course of testing or treatment is in a patient’s best interest, you have to look at the stats on likely benefits and harms of various courses of action. I’d love to know what my patients have before hand, so I could avoid dealing with probabilities, but I haven’t been blessed with that particular power. I’d love for the data to exist to tell me how to interpret a result in my precise patient rather than a larger population she belongs to, but “solitary pulmonary nodules in 33-year old men who smoked twice in college and live half a mile from a freeway with two episodes of bronchitis in their teens” is a study that hasn’t been conducted yet. One day perhaps it will be, and if so, I’ll be grateful for it. But right now that data doesn’t exist, so we use what we have, and use our judgment to tailor it to the patient in front of us - imperfectly.
I recommend reading “overdiagnosed” by Gilbert Welch.
And of course we make statistical calls! When you’re deciding -prospectively- whether a course of testing or treatment is in a patient’s best interest, you have to look at the stats on likely benefits and harms of various courses of action. I’d love to know what my patients have before hand, so I could avoid dealing with probabilities, but I haven’t been blessed with that particular power. I’d love for the data to exist to tell me how to interpret a result in my precise patient rather than a larger population she belongs to, but “solitary pulmonary nodules in 33-year old men who smoked twice in college and live half a mile from a freeway with two episodes of bronchitis in their teens” is a study that hasn’t been conducted yet. One day perhaps it will be, and if so, I’ll be grateful for it. But right now that data doesn’t exist, so we use what we have, and use our judgment to tailor it to the patient in front of us - imperfectly.
I recommend reading “overdiagnosed” by Gilbert Welch.
> judgment
> make statistical calls!
Really? Your fuzzy feels are not statistics.
Do you even at least try to know how large is the type 2 error in your guesswork? Is it better than flipping a coin?
> make statistical calls!
Really? Your fuzzy feels are not statistics.
Do you even at least try to know how large is the type 2 error in your guesswork? Is it better than flipping a coin?
I think the pointless trap is often the patient. I worry less than some but more than many, and while I usually defer to my doctor's advice to leave most of life's little lumps and bumps be, it's a challenge for me to accept the unknown. I imagine that many patients will demand answers once they know that any anomaly exists, no matter how likely the benign explanation is.
Yeah, just look at the number of people that demand antibiotics, even if a doctor thinks its viral, and the number of doctors that capitulate to those demands.
Yeah, emotions, money and politics aside, more information is surely better, even if not now, in the long run as processes improve.
>Why can't a doctor see an anomaly and decide not to chase it down based on the same reasoning that they use to not scan for it
Mostly it is just how the medical industry works. A previous co-worker of mine had a wife that ran a small family practice. He was always griping about the money they spent on insurance for the place ($20k a year or quarterly, can't remember). I asked why it was so much, and case in point, he told of a story just in the prior year of a woman that came in for a knot on her breast. She was informed to come back in a month as sometimes hormones can cause them to come and go. Well they never saw her again but a year later they got a malpractice lawsuit from her since she now had breast cancer...
Mostly it is just how the medical industry works. A previous co-worker of mine had a wife that ran a small family practice. He was always griping about the money they spent on insurance for the place ($20k a year or quarterly, can't remember). I asked why it was so much, and case in point, he told of a story just in the prior year of a woman that came in for a knot on her breast. She was informed to come back in a month as sometimes hormones can cause them to come and go. Well they never saw her again but a year later they got a malpractice lawsuit from her since she now had breast cancer...
Most tests are probabilistic and you have to think about the conditional probability given other indicators. Consider a urine culture for detecting UTIs. If you just get urine samples from a general population, some fraction will show positive (bacteria in the culture) falsely. It would be pointless to perform this test on the general population and to treat people that show positive . But if you perform this test conditioned on the fact that the patient is presenting other symptoms (burning sensation, fever etc.) then the same test very useful and the conditional false probability is low enough that it can be used to decide on treatment.
The same idea applies to most tests in medicine. That is why tests are mostly done conditionally.
The same idea applies to most tests in medicine. That is why tests are mostly done conditionally.
But why can't they go the other way? Oh, you had bacteria in your urine, do you feel a burning or have a fever? You'd have to find a way to ask that doesn't incite a false response, but it still seems like it would be useful.
Some folks have raised plenty of practical/medicolegal reasons, but it's also worth noting that patients are often not comfortable being told that they have an "anomaly" that their doc is going to sit back and do nothing about. There's a lot to be said for the psychiatric implications of being aware of benign MRI findings.
Even if you (or anyone, for that matter) might be comfortable with that, I think you'd find that a lot of patients wouldn't be.
Even if you (or anyone, for that matter) might be comfortable with that, I think you'd find that a lot of patients wouldn't be.
It seems like the solution to this would be more frequent scans, so doctors can determine what's a static anomaly, and what is actually changing over time.
Limiting patient information for fear of false positive seems like a backwards step.
You're describing a problem with the doctors, not a problem with the scans. I'm curious to understand the real motivation to avoid information. Is it something in the system, litigation risk?
There are many ways to deal with incidentalomas. If full body scans were more widespread, maybe doctors would have confidence to deal with them properly. For example, watching them over time.
There are many ways to deal with incidentalomas. If full body scans were more widespread, maybe doctors would have confidence to deal with them properly. For example, watching them over time.
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> watching them over time
In my mind this is the key... a way to frequently and conveniently do a full body scan so that anomalies can be detected via the delta. Scanning and detection is a problem that likely could be tackled via machine learning.
I'm hoping it's not too long before a method is developed where a low res MRI like scan is feasible at home (e.g. using radio or ultrasound).
Done on a regular basis the system could detect anomalies like the appearance or enlargement of a growth inside the body.
In my mind this is the key... a way to frequently and conveniently do a full body scan so that anomalies can be detected via the delta. Scanning and detection is a problem that likely could be tackled via machine learning.
I'm hoping it's not too long before a method is developed where a low res MRI like scan is feasible at home (e.g. using radio or ultrasound).
Done on a regular basis the system could detect anomalies like the appearance or enlargement of a growth inside the body.
Obtaining the delta from two different images is actually non trivial. And contrary to what HN thinks, not every problem is trivially solved by machine learning.
Small point aside: an ultrasound scan -- even if it was every feasible at home -- would not be an MRI. MRI means you use the spin echo and relaxation of nucleii (mostly protons for medical MRI). It is not a generic word for "please give me a 3d image". Words have meanings, especially when they are technical jargon, and it is important to not dilute that if we want to be able to communicate efficiently and effectively.
Also: technology that is more mature than software tends to improve at a more measured pace, as all but the hardest breakthroughs have been obtained already. It is therefore unlikely that you will be able to replace a 10 million dollar machine by things in your home any time soon.
Small point aside: an ultrasound scan -- even if it was every feasible at home -- would not be an MRI. MRI means you use the spin echo and relaxation of nucleii (mostly protons for medical MRI). It is not a generic word for "please give me a 3d image". Words have meanings, especially when they are technical jargon, and it is important to not dilute that if we want to be able to communicate efficiently and effectively.
Also: technology that is more mature than software tends to improve at a more measured pace, as all but the hardest breakthroughs have been obtained already. It is therefore unlikely that you will be able to replace a 10 million dollar machine by things in your home any time soon.
You are exaggerating just a bit: https://info.blockimaging.com/bid/92623/mri-machine-cost-and...
Still not something you’d have in your home, but not nearly 10M dollars. Maybe you can have one in your community medical center?
Still not something you’d have in your home, but not nearly 10M dollars. Maybe you can have one in your community medical center?
These are old MRIs using low fields and limited slew rates. They will give you poor resolution, limited dynamic range and long scan durations (Which makes is even harder to avoid artefacts from patient motion). Check the price tags on new 3T or even 7T machines and they come close to the 10M I mentioned.
Sounds like prime territory for machine learning, though I don't know how much variance there can be in the presentation of anomalies and how much training data you'd therefore need.
Do tumors from various cancers typically share any discernable features?
Do tumors from various cancers typically share any discernable features?
I think I was advised once not to take a test for Lyme Disease unless I had other fairly clear indicators because of the cost of a false positive.
Why not employ those fancy new neural networks for analyzing images? Have the doctor and the software identify anomalies separately and compare outcomes.
But this is exactly what an “executive scan” is. I know several CEOs who get full body scans. Two of them caught early stage cancers and credit these scans with vastly improving their prognosis.
A counterpoint to these stories of early diagnosis is that not all cancers are equal, and there are some cancers which may not ever have affected the patient had they not been treated (or detected). Examples include some prostate and breast cancers. Autopsy studies have shown occult prostate cancer in about half of men > 70 years old who were asymptomatic and died of other causes.
Of course it is often impossible to know which cancer will or won't kill you, but it should be recognized that there is a risk to scanning oneself without a proper indication, for example, getting a prostatectomy for indolent prostate cancer and risking impotence.
Of course it is often impossible to know which cancer will or won't kill you, but it should be recognized that there is a risk to scanning oneself without a proper indication, for example, getting a prostatectomy for indolent prostate cancer and risking impotence.
In Canada, these "executive scans" are a service sold by private clinics. As OP pointed out, they will often find things that are entirely benign. However, since in Canada you can't charge money privately for services that are covered under public insurance, guess who ends up paying for the bulk of the inevitable follow-up investigations coming out of these full-body scans that only the wealthy can afford.
A decent portion of my family are MDs. This is accurate.
However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we do receive.
A stream of known false positives is worth its weight in gold in any detection system, it's just that this specific system happens to contain squishy feely human doctors that are susceptible to short-term human 'Please don't spend more money than necessary, we're already in the red for this quarter' kind of pressures from their superiors.
Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree, which would counteract the temporary cost increase in chasing false positives. The fact that we don't want to eat the short term initial cost means some of those things that could be uncovered by the scan, things that could save a person from a malignant deviation, is left unseen, untreated, to its natural end.
However, this is also one of the places where it's quite disappointing to see human squishiness in action. When we opt to not receive data because we know there'll likely be non-malignant anomalies, we are also depriving ourselves of the raw data that allows us to discern non-malignant from malignant, data which would help very much in deciding on the cases we do receive.
A stream of known false positives is worth its weight in gold in any detection system, it's just that this specific system happens to contain squishy feely human doctors that are susceptible to short-term human 'Please don't spend more money than necessary, we're already in the red for this quarter' kind of pressures from their superiors.
Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree, which would counteract the temporary cost increase in chasing false positives. The fact that we don't want to eat the short term initial cost means some of those things that could be uncovered by the scan, things that could save a person from a malignant deviation, is left unseen, untreated, to its natural end.
You're understating the costs.
Determining whether something is (non) malignant isn't trivial. It often requires a more invasive test (e.g., biopsy, exploratory surgery). We try to avoid those procedures not just because we're cheap or afraid, but because they have a real risk of harming us 'squishy humans'.
For example, detecting prostate cancer a few months earlier is often not a huge win on its own. It is even less of a success if doing so requires that four people have allergic reactions to the anesthetic and two others acquire some kind of infection at the biopsy site.
It's certainly possible that more data would eventually let us avoid most invasive followups, that's nowhere near certain. Even if it were, the ethical calculus is still pretty tricky.
Determining whether something is (non) malignant isn't trivial. It often requires a more invasive test (e.g., biopsy, exploratory surgery). We try to avoid those procedures not just because we're cheap or afraid, but because they have a real risk of harming us 'squishy humans'.
For example, detecting prostate cancer a few months earlier is often not a huge win on its own. It is even less of a success if doing so requires that four people have allergic reactions to the anesthetic and two others acquire some kind of infection at the biopsy site.
It's certainly possible that more data would eventually let us avoid most invasive followups, that's nowhere near certain. Even if it were, the ethical calculus is still pretty tricky.
”Determining whether something is (non) malignant isn't trivial. It often requires a more invasive test (e.g., biopsy, exploratory surgery)”
Not necessarily, waiting can in many cases tell you whether something is malignant. If we had, say, a century of monthly full-body MRIs of a million persons, together with their history and cause of death, the technology to align those scans across time, and the technology to analyze such a data set, a retrospective cohort study (https://en.wikipedia.org/wiki/Retrospective_cohort_study) probably could uncover quite some interesting and useful information.
If, at every step, you pick the option with the highest expected QALYs (https://en.wikipedia.org/wiki/Quality-adjusted_life_year), and you manage to make doing the MRI very efficient, I think doing that experiment even might pass an ethics committee (at the cost of making the analysis harder)
(might because one could argue that the patient would be better of if the money spent doing those MRIs were spent on something else)
Unfortunately, doing such an experiment isn’t practical (¿yet?).
Not necessarily, waiting can in many cases tell you whether something is malignant. If we had, say, a century of monthly full-body MRIs of a million persons, together with their history and cause of death, the technology to align those scans across time, and the technology to analyze such a data set, a retrospective cohort study (https://en.wikipedia.org/wiki/Retrospective_cohort_study) probably could uncover quite some interesting and useful information.
If, at every step, you pick the option with the highest expected QALYs (https://en.wikipedia.org/wiki/Quality-adjusted_life_year), and you manage to make doing the MRI very efficient, I think doing that experiment even might pass an ethics committee (at the cost of making the analysis harder)
(might because one could argue that the patient would be better of if the money spent doing those MRIs were spent on something else)
Unfortunately, doing such an experiment isn’t practical (¿yet?).
Two reasons I think this is not the way to go:
First, the cost would be insane. A century of monthly MRIs is 1200 scans per person, or 1.2B scans to finish your hypothetical dataset. We pay about $US 550/hr for scanner time, using a research scanner that's subsidized (i.e., we're just covering costs, not making a profit). The article doesn't say how long the scan is. You can burn as much scanner time as you want chasing resolution/quality, but an hour seems reasonable. That comes out to $660B, which is...a lot, and we haven't even paid staff yet!
Second, we have sorta tried this already. There's a massive neuroscience project to scan tons of brains called the Human Connectome Project. They have 1200 subjects, some scanned multiple times, behavioral measures, health outcomes, the works....
People have certainly found stuff in the data (I'm using some of it right now), but it hasn't lead to wild breakthroughs. There's a ongoing debate about whether this money would have been better spent on hypothesis-driven research instead.
First, the cost would be insane. A century of monthly MRIs is 1200 scans per person, or 1.2B scans to finish your hypothetical dataset. We pay about $US 550/hr for scanner time, using a research scanner that's subsidized (i.e., we're just covering costs, not making a profit). The article doesn't say how long the scan is. You can burn as much scanner time as you want chasing resolution/quality, but an hour seems reasonable. That comes out to $660B, which is...a lot, and we haven't even paid staff yet!
Second, we have sorta tried this already. There's a massive neuroscience project to scan tons of brains called the Human Connectome Project. They have 1200 subjects, some scanned multiple times, behavioral measures, health outcomes, the works....
People have certainly found stuff in the data (I'm using some of it right now), but it hasn't lead to wild breakthroughs. There's a ongoing debate about whether this money would have been better spent on hypothesis-driven research instead.
6B per year to figure out which cancers are malignant with one scan seems like a fairly decent price.
For comparison, the entire NSF budget for next year is around $7B. That would just about cover the imaging component of building a speculative and ethically-questionable data set, assuming someone else pays for the biopsies, analysis, and staff.
(The NIH does have more money, but also funds trials, vaccines, and other stuff that we probably don't want to cancel for a century).
(The NIH does have more money, but also funds trials, vaccines, and other stuff that we probably don't want to cancel for a century).
Why would this be ethically questionable? It is not as if you are scanning people against their will.
> You can burn as much scanner time as you want chasing resolution/quality, but an hour seems reasonable.
Out of curiosity, what determines the speed of the MRI scan? Are massive improvements theoretically possible?
Out of curiosity, what determines the speed of the MRI scan? Are massive improvements theoretically possible?
ML & better imaging algorithms should help a lot. Times could be reduced from 45min to 15min [1]. Scanning a beating heart can be reduced from 4min+ to 25sec [2]. Also ML can aid in comparing past images to current ones [3], which would give you quick insights into what changed.
Two ideas for time reduction I haven't seen discussed but perhaps might also help:
1. Don't scan at the same resolution across the whole body each time. Instead, focus on anomalous places that you wanted to monitor from the first high-res scan, or places that look anomalous in low res in the latest scan. Then dial up the resolution in those areas.
2. If better imaging algorithms existed that could account for very slight movements of the body (ala the heartbeat one above), perhaps prep time could be reduced by changing the physical layout of the scanner itself. The whole process of lying down and getting your head or whatever mounted in their plastic frame, then lifting the gurney and slowly sliding it into the machine.. it's all very slow.
Instead of laying down, what if you could just walk in and be upright and get scanned relatively quickly - basically a slightly longer but similar experience to a chest X-ray. There's upright MRIs right now but they're not very high res (0.7tesla instead of 1-3), very few exist, and I'm sure they still take some time to complete scans and have lots of error correction extra scans to correct for patient movement.
However, even with less time in scanner, there's a lot of fixed time cost of scheduling and patient prep (remove all metal things, wear this gown and these ear plugs, please don't freak out its really claustrophobic patient messaging), as well as still needing technicians.
I'm just a patient who's gotten some MRIs but it definitely feels like there's ways to cut the time down significantly.
[1] http://news.mit.edu/2011/better-mri-algorithm-1101
[2] https://phys.org/news/2017-10-technology-mri-scan.html
[3] http://news.mit.edu/2018/faster-analysis-of-medical-images-0...
Two ideas for time reduction I haven't seen discussed but perhaps might also help:
1. Don't scan at the same resolution across the whole body each time. Instead, focus on anomalous places that you wanted to monitor from the first high-res scan, or places that look anomalous in low res in the latest scan. Then dial up the resolution in those areas.
2. If better imaging algorithms existed that could account for very slight movements of the body (ala the heartbeat one above), perhaps prep time could be reduced by changing the physical layout of the scanner itself. The whole process of lying down and getting your head or whatever mounted in their plastic frame, then lifting the gurney and slowly sliding it into the machine.. it's all very slow.
Instead of laying down, what if you could just walk in and be upright and get scanned relatively quickly - basically a slightly longer but similar experience to a chest X-ray. There's upright MRIs right now but they're not very high res (0.7tesla instead of 1-3), very few exist, and I'm sure they still take some time to complete scans and have lots of error correction extra scans to correct for patient movement.
However, even with less time in scanner, there's a lot of fixed time cost of scheduling and patient prep (remove all metal things, wear this gown and these ear plugs, please don't freak out its really claustrophobic patient messaging), as well as still needing technicians.
I'm just a patient who's gotten some MRIs but it definitely feels like there's ways to cut the time down significantly.
[1] http://news.mit.edu/2011/better-mri-algorithm-1101
[2] https://phys.org/news/2017-10-technology-mri-scan.html
[3] http://news.mit.edu/2018/faster-analysis-of-medical-images-0...
Your first idea is pretty common. There's usually a very coarse "localizer" scan at the beginning of a session, which is used to set the field of view for subsequent runs. The whole body scans are (at least in theory) meant to find tiny things that are asymptotic though, so I'm not sure that searching through (say) 10mm slabs will help much.
Open, upright scanners do exist, but they're lousy. The goal of the (big) magnet is to produce an incredibly strong, uniform magnetic field. Due to physics, this is much, much easier to do with a torus-shaped magnet than a 'U'shaped one. Even so, there's one point ('isocenter') where the magnetic field is maximally flat and the quality will be best. The gurney moves to point the region of interest (e.g., your head) right to the isocenter. That's why the tech often uses a little light or laser to find your position, rather than just asking you to scooch. Motion is also, as you alluded, a huge problem.
I hate to be discouraging, but I am excited to see people actually thinking about MRI on HN!.
Open, upright scanners do exist, but they're lousy. The goal of the (big) magnet is to produce an incredibly strong, uniform magnetic field. Due to physics, this is much, much easier to do with a torus-shaped magnet than a 'U'shaped one. Even so, there's one point ('isocenter') where the magnetic field is maximally flat and the quality will be best. The gurney moves to point the region of interest (e.g., your head) right to the isocenter. That's why the tech often uses a little light or laser to find your position, rather than just asking you to scooch. Motion is also, as you alluded, a huge problem.
I hate to be discouraging, but I am excited to see people actually thinking about MRI on HN!.
Physics, partly.
MRI is all about the protons. Under normal conditions, the protons in your body are all spinning ('precessing') around their own axis, but they're disorganized: each proton's axis is pointing in a different direction. They're like little wobbly tops drifting through space.
In an MRI scanner, the strong static magnetic field (B_0) forces the protons into alignment, so that their rotational axes are now lined up with the field's north-south axis. The field needs to be very strong for this to work, which is why MRI systems usually have expensive superconducting magnets.
Now that we've created a nice organized system, we're going to destroy it. A quick radio frequency burst energizes the protons and 'knocks them over' so they're no longer aligned with the field. Once the pulse ends, they 'relax' and realign themselves with the magnetic field, releasing some of that energy as they do so.
Sensitive detectors around the subjects' head detect those emissions and use it to determine how long it took for protons to realign themselves with the different components of the magnetic field. T1 is the time (or formally, the time constant) needed for relaxation parallel to the static field; T2 is the time needed for protons to relax to the transverse component. The T1 relaxation time for fluids is on the order of seconds, while fatty issue is more like 50-150ms. In the brain, grey matter has a relaxation time of 1.3 sec, but the fat-coated white matter relaxes much faster (~0.8), which makes T1 images very useful for examining brain anatomy.
Hopefully, this little crash course has revealed one of the bottlenecks in MRI: the actual signal being measured is slow.
Of course, I've massively oversimplified things and didn't explain at all how we localize these responses. The proton's precession frequency depends on the magnetic field, so by changing the static field slightly (across space), we can measure T1 at different locations, and sometimes even overlap measurements. You can't switch the field too fast though, or you'll start to induce currents in the subjects' nerves, which hurts. This is actually the principle behind a brain stimulation technique called transcranial magnetic stimulation.
There is still tons of room for improvement. Stronger fields lower the relaxation time, so the scans are faster (and the relaxation time estimates are better). Improvements in the RF coils help a lot too: the signal being measured is very faint and there's a lot of self-cancellation. On the software side of things, a lot of effort has already gone into designing clever pulse sequences—and the sophisticated signal processing needed to interpret their results.
Things will obviously continue to get better; I was just looking at some data from ten years ago and it looks awful compared to more recent scans.
That said, the "just use machine learning!!!" tone in some of the comments is kinda frustrating. Most of the people in this field aren't dummies--if it were as easy as downloading PyTorch, someone would have done it already. It turns out that the biology and physics are both stupendously complicated (and fascinating too).
MRI is all about the protons. Under normal conditions, the protons in your body are all spinning ('precessing') around their own axis, but they're disorganized: each proton's axis is pointing in a different direction. They're like little wobbly tops drifting through space.
In an MRI scanner, the strong static magnetic field (B_0) forces the protons into alignment, so that their rotational axes are now lined up with the field's north-south axis. The field needs to be very strong for this to work, which is why MRI systems usually have expensive superconducting magnets.
Now that we've created a nice organized system, we're going to destroy it. A quick radio frequency burst energizes the protons and 'knocks them over' so they're no longer aligned with the field. Once the pulse ends, they 'relax' and realign themselves with the magnetic field, releasing some of that energy as they do so.
Sensitive detectors around the subjects' head detect those emissions and use it to determine how long it took for protons to realign themselves with the different components of the magnetic field. T1 is the time (or formally, the time constant) needed for relaxation parallel to the static field; T2 is the time needed for protons to relax to the transverse component. The T1 relaxation time for fluids is on the order of seconds, while fatty issue is more like 50-150ms. In the brain, grey matter has a relaxation time of 1.3 sec, but the fat-coated white matter relaxes much faster (~0.8), which makes T1 images very useful for examining brain anatomy.
Hopefully, this little crash course has revealed one of the bottlenecks in MRI: the actual signal being measured is slow.
Of course, I've massively oversimplified things and didn't explain at all how we localize these responses. The proton's precession frequency depends on the magnetic field, so by changing the static field slightly (across space), we can measure T1 at different locations, and sometimes even overlap measurements. You can't switch the field too fast though, or you'll start to induce currents in the subjects' nerves, which hurts. This is actually the principle behind a brain stimulation technique called transcranial magnetic stimulation.
There is still tons of room for improvement. Stronger fields lower the relaxation time, so the scans are faster (and the relaxation time estimates are better). Improvements in the RF coils help a lot too: the signal being measured is very faint and there's a lot of self-cancellation. On the software side of things, a lot of effort has already gone into designing clever pulse sequences—and the sophisticated signal processing needed to interpret their results.
Things will obviously continue to get better; I was just looking at some data from ten years ago and it looks awful compared to more recent scans.
That said, the "just use machine learning!!!" tone in some of the comments is kinda frustrating. Most of the people in this field aren't dummies--if it were as easy as downloading PyTorch, someone would have done it already. It turns out that the biology and physics are both stupendously complicated (and fascinating too).
At that scale, scans wouldn’t cost $550 per hour.
“Because it’s too expensive,” seems like a great opportunity for some clever startup to figure out a way to make it less expensive. Computers used to take up entire rooms. Flying across the country used to be insanely expensive. Cell phones used to cost a ton of money per minute. Reducing the cost of scanning, or developing entirely new scanning tech isn’t science fiction, it’s the future.
“Because it’s too expensive,” seems like a great opportunity for some clever startup to figure out a way to make it less expensive. Computers used to take up entire rooms. Flying across the country used to be insanely expensive. Cell phones used to cost a ton of money per minute. Reducing the cost of scanning, or developing entirely new scanning tech isn’t science fiction, it’s the future.
$98/scan in Japan.
https://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/...
https://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/...
The doctor gets $98. The $550/hr price I quoted is for a research scanner where no one is even trying to turn a profit; they just want to pay off the machine and its operating costs.
The machines themselves are not magically cheaper in Japan; they're just being paid for through some other route. If the scanner were somehow free (gov't grant?), 98$ seems pretty reasonable for the labor.
The machines themselves are not magically cheaper in Japan; they're just being paid for through some other route. If the scanner were somehow free (gov't grant?), 98$ seems pretty reasonable for the labor.
A medical grade MRI scanner costs around $1 million, and maintenance costs are circa $100,000/year. With good utilisation, say 3000 hrs/year, the machine costs might be around $70/hr.
The $550/hr you are paying may be because you are using a particularly fancy scanner, or because utilisation rate is low, or because the amount is loaded with overheads, or w/e.
The $550/hr you are paying may be because you are using a particularly fancy scanner, or because utilisation rate is low, or because the amount is loaded with overheads, or w/e.
[deleted]
What does “medical grade” mean?
That’s in the ballpark for a 1.5T, but those are fairly old. About $1M per Tesla used to be a decent rule of thumb, but it’s come down a little at the low end. Still, I would be amazed to see a 3T for anything below $2M.
As for the $550/hr, it’s probably true that research scanners have lower utilization and higher costs to support all the weird stuff researchers want to do. An outpatient clinic specializing in knees can run much leaner. That said, that rate seems to be pretty standard across universities and I maintain that it's a very reasonable estimate of the cost. For example:
* Hopkins $668/hr (3T) or $538 (1.5T) during prime time; cheaper nights and weekend http://www.mri.jhu.edu/div_mri_res/ServCentPolicyFY17.pdf
* Yale: $539/hr (3T) https://medicine.yale.edu/mrrc/users/charges.aspx
* Harvard/MGH: $640/hr https://www.nmr.mgh.harvard.edu/core
* WUSTL: $710/hr (3T) https://www.mir.wustl.edu/Portals/0/Documents/Uploads/CCIR/F...
* McGill: $500/hr (3T) or $500-700/hr (7T) https://mcgill.ca/bic/files/bic/bic-rates-03052018.pdf
Most of these do not include F&A. It’s already coming out of the grants and external users pay a "Dean's Tax" on top of that to cover the missing overhead (which can often double the price).
That’s in the ballpark for a 1.5T, but those are fairly old. About $1M per Tesla used to be a decent rule of thumb, but it’s come down a little at the low end. Still, I would be amazed to see a 3T for anything below $2M.
As for the $550/hr, it’s probably true that research scanners have lower utilization and higher costs to support all the weird stuff researchers want to do. An outpatient clinic specializing in knees can run much leaner. That said, that rate seems to be pretty standard across universities and I maintain that it's a very reasonable estimate of the cost. For example:
* Hopkins $668/hr (3T) or $538 (1.5T) during prime time; cheaper nights and weekend http://www.mri.jhu.edu/div_mri_res/ServCentPolicyFY17.pdf
* Yale: $539/hr (3T) https://medicine.yale.edu/mrrc/users/charges.aspx
* Harvard/MGH: $640/hr https://www.nmr.mgh.harvard.edu/core
* WUSTL: $710/hr (3T) https://www.mir.wustl.edu/Portals/0/Documents/Uploads/CCIR/F...
* McGill: $500/hr (3T) or $500-700/hr (7T) https://mcgill.ca/bic/files/bic/bic-rates-03052018.pdf
Most of these do not include F&A. It’s already coming out of the grants and external users pay a "Dean's Tax" on top of that to cover the missing overhead (which can often double the price).
$105 in Romania then, for most body parts.
<http://www.hiperdia.ro/servicii-medicale/>
<http://www.hiperdia.ro/servicii-medicale/>
Again, that’s what you pay (near as I can tell), but that’s not what it costs.
They’re also “free” (at the point of service) in the UK, but the scanner and helium are not a generous gift from the fey folk, nor does the Queen volunteer as a tech.
These things cost money. Any study you do is going to have to cover expenses—-including their share of a temperamental, multimillion dollar machine (or find a way to dip into the same accounts that cover its clinical use).
They’re also “free” (at the point of service) in the UK, but the scanner and helium are not a generous gift from the fey folk, nor does the Queen volunteer as a tech.
These things cost money. Any study you do is going to have to cover expenses—-including their share of a temperamental, multimillion dollar machine (or find a way to dip into the same accounts that cover its clinical use).
It is actually what I paid at the front desk in cash :) Totally anonymous. I visited as a tourist. It is not a subsidized government hospital.
That is just for your neck. So a tiny imaging volume on a cheaper machine. Using that as a price point for full body imageing is disingenuous.
You're understating the costs.
I think you're correct in the current context. However, this strikes me as a sign of some kind of paradigm shift waiting to happen, enabled by the reduced cost of data gathering, data processing, and improvements in AI.
There was a time when many things which are mass produced now were once handcrafted luxury items. Perhaps, as technology improves, it will one day be cost effective to take a whole body scan into account. I can imagine a day when an AI would digest the information from a full body scan, then autonomously plan robot keyhole surgery to take many of the biopsies.
It's certainly possible that more data would eventually let us avoid most invasive followups, that's nowhere near certain.
I think it's likely to happen in decades, if our civilization doesn't fall soon.
I think you're correct in the current context. However, this strikes me as a sign of some kind of paradigm shift waiting to happen, enabled by the reduced cost of data gathering, data processing, and improvements in AI.
There was a time when many things which are mass produced now were once handcrafted luxury items. Perhaps, as technology improves, it will one day be cost effective to take a whole body scan into account. I can imagine a day when an AI would digest the information from a full body scan, then autonomously plan robot keyhole surgery to take many of the biopsies.
It's certainly possible that more data would eventually let us avoid most invasive followups, that's nowhere near certain.
I think it's likely to happen in decades, if our civilization doesn't fall soon.
Perhaps, as technology improves, it
will one day be cost effective to
take a whole body scan into account.
It's nice that you think those are costs worth remaining ignorant over. However, when the ignorance is about things that literally might kill me, my personal opinion is that it's worth it.
The word 'cost' seems to be confusing things.
Both options have risks and both options can kill you. Namely:
A) Doing nothing may allow a problem to fester until it either kills you or becomes detectable with standard treatments. However, you have no exposure whatsoever to side effects, infections, or medical errors for the things that are missed.
B) Doing whole-body MRI 'fishing expeditions' decreases the risk of missing something, but increases the likelihood of possible false positives. Each thing flagged by the scan now needs to be ruled out (otherwise, why bother?) and this usually requires invasive procedures with their own risks.
With our current imaging and understanding of biology, Option A may be less likely to kill people. Opinion doesn't even have to enter into this--you can literally run the numbers.
It's worth noting that we limit testing FOR EVERYTHING. When you get a blood test, you could be screened for everything from ADH to Zika. You aren't though, because you're almost certainly a perfectly healthy outlier on a few tests; that's just how statistics work (someone has to be 3 sigma above the mean). Instead, tests are picked and interpreted based on your symptoms and circumstances.
Both options have risks and both options can kill you. Namely:
A) Doing nothing may allow a problem to fester until it either kills you or becomes detectable with standard treatments. However, you have no exposure whatsoever to side effects, infections, or medical errors for the things that are missed.
B) Doing whole-body MRI 'fishing expeditions' decreases the risk of missing something, but increases the likelihood of possible false positives. Each thing flagged by the scan now needs to be ruled out (otherwise, why bother?) and this usually requires invasive procedures with their own risks.
With our current imaging and understanding of biology, Option A may be less likely to kill people. Opinion doesn't even have to enter into this--you can literally run the numbers.
It's worth noting that we limit testing FOR EVERYTHING. When you get a blood test, you could be screened for everything from ADH to Zika. You aren't though, because you're almost certainly a perfectly healthy outlier on a few tests; that's just how statistics work (someone has to be 3 sigma above the mean). Instead, tests are picked and interpreted based on your symptoms and circumstances.
Speaking of blood tests - where does the uncertainty come in there? Is the measuring equipment noisy, so they might detect some marker when it is actually not present? Or is it that you can actually have a high concentration of whatever they are looking for in your blood but it somehow just be normal for you because you are an outlier?
I tend to think it is the former but can anyone clarify?
I tend to think it is the former but can anyone clarify?
Uncertainty is everywhere!
The normative values aren't handed down from God, or some definite evidence of health. Instead, they were the typical range (mean ± 3SD, percentiles, etc) from a sample of healthy people, possibly matched for demographics (e.g., sex). Suppose we set each range so that it contains 99/100 healthy people. It would only take about 70 independent tests before you have a 50:50 chance of being outside that range on one of them--and that's assuming you're an exact match for the reference population.
There's also error in the measurements themselves. Some of it is errors in the actual procedure or preparation: cross-contamination between samples, dust blows into the well, etc. However, many of the tests are stochastic too. Some measure binding between stuff in your blood (e.g., antibodies) and a "probe" that's designed to detect them. This usually works, but non-specific binding can cause false positives (the probe binds something that is similar to, but not quite the same as, the target). Other conditions can cause false negatives. The "front line" screenings are usually meant to be cheap, fast, and biased towards false positives.
You might be interested in a fairly common statistics question about screening. Suppose you had a test that is 99% reliable: 99% of sick people test positive; 99% of healthy people test negative. The disease itself is somewhat rare--only 1% of people have it. If you test positive, what are the odds you're actually sick? The answer[0] will explain why we don't test or scan people for tons of rare diseases, even with very reliable (and free) tests.
[0] ʎʇɟᴉɟ-ʎʇɟᴉɟ
The normative values aren't handed down from God, or some definite evidence of health. Instead, they were the typical range (mean ± 3SD, percentiles, etc) from a sample of healthy people, possibly matched for demographics (e.g., sex). Suppose we set each range so that it contains 99/100 healthy people. It would only take about 70 independent tests before you have a 50:50 chance of being outside that range on one of them--and that's assuming you're an exact match for the reference population.
There's also error in the measurements themselves. Some of it is errors in the actual procedure or preparation: cross-contamination between samples, dust blows into the well, etc. However, many of the tests are stochastic too. Some measure binding between stuff in your blood (e.g., antibodies) and a "probe" that's designed to detect them. This usually works, but non-specific binding can cause false positives (the probe binds something that is similar to, but not quite the same as, the target). Other conditions can cause false negatives. The "front line" screenings are usually meant to be cheap, fast, and biased towards false positives.
You might be interested in a fairly common statistics question about screening. Suppose you had a test that is 99% reliable: 99% of sick people test positive; 99% of healthy people test negative. The disease itself is somewhat rare--only 1% of people have it. If you test positive, what are the odds you're actually sick? The answer[0] will explain why we don't test or scan people for tons of rare diseases, even with very reliable (and free) tests.
[0] ʎʇɟᴉɟ-ʎʇɟᴉɟ
> For example, detecting prostate cancer a few months earlier is often not a huge win on its own. It is even less of a success if doing so requires that four people have allergic reactions to the anesthetic and two others acquire some kind of infection at the biopsy site.
Then the doctor should recommend not attempting that type of detection.
I find it quite hard to believe that, in an ideal world (!), less data would actually be better. The doctor should still have the ability (at least in theory) to decide what information is worth investigating further, and what should be ignored.
Then the doctor should recommend not attempting that type of detection.
I find it quite hard to believe that, in an ideal world (!), less data would actually be better. The doctor should still have the ability (at least in theory) to decide what information is worth investigating further, and what should be ignored.
Sure, in the not-for-profit Vulcan medical system, this would might be grand. Even in our world I'd agree that in isolation, more information is always better.
The issue is that this sort of information isn't free. The full body scan isn't free. Following up on it, which is the whole point, 'costs' increased risks of adverse outcomes (from biopsies), it 'costs' emotional anxiety, and it costs even more actual money.
The argument is that right now, these whole body scans aren't worth the cost. You're more likely to find a few things you should ignore (but will probably worry over) and a few things you should follow up on (but will be benign). You're less likely to catch something deadly and just in the nick of time.
The issue is that this sort of information isn't free. The full body scan isn't free. Following up on it, which is the whole point, 'costs' increased risks of adverse outcomes (from biopsies), it 'costs' emotional anxiety, and it costs even more actual money.
The argument is that right now, these whole body scans aren't worth the cost. You're more likely to find a few things you should ignore (but will probably worry over) and a few things you should follow up on (but will be benign). You're less likely to catch something deadly and just in the nick of time.
In the US system with malpractice lawsuits, there will be followup in most cases. US Doctors are still furious over the amount of unnecessary testing that occurred as a result of the "whole body scan at third party facility" fad from a decade or two ago.
We should focus on the core problem, instead of "this device gives patients too much data."
The core problem is there is zero evidence that a whole-body scan saves more lives than are lost due to the radiation of a whole-body scan.
The idea that lots of full body MRIs will necessarily lead to better discrimination of malignant vs benign anomalies assumes that the imaging is able to detect differences at all, which often is not true. Some benign and malignant abnormalities can look _exactly_ the same on imaging, particularly at an early stage, when you could make a difference, for example lung nodules. Nevermind the fact that many benign entities can undergo malignant transformation at some point in the future. Or that MRI is only a good test for a subset of cancers, CT is better for others. All these issues help explain why doctors are averse to full-body scanning everybody. It is neither cost-effective nor medically sensible.
I think their statement is more general than what you're making it out to be. The goal of receiving better and more data puts pressure to have better imaging technology.
I think there are perverse incentives at work, too. If running the MRI machine cost $100, people would do it. If it can bill insurance $100k, and then any follow up might cost $500k, there is a rational aversion to doing it as it might make the _system_ less good for everyone if insurance cracked down on exploratory imaging as a billable thing (obviously, they already do this to some extent).
Better technology is unlikely to be cheaper, unless it is so new and novel that it can get its own unique billing codes, and if it becomes ubiquitous so it cheaper and more available than existing machines which are not yet depreciated.
Just typing that out depresses me.
Better technology is unlikely to be cheaper, unless it is so new and novel that it can get its own unique billing codes, and if it becomes ubiquitous so it cheaper and more available than existing machines which are not yet depreciated.
Just typing that out depresses me.
>If running the MRI machine cost $100, people would do it.
There are different kinds of MRIs, but the actual direct costs for running an MRI without preparatory procedures is around $100 (preparatory dye injection may be another $50 cost). Marginal costs are lower still.
See also here:
https://www.npr.org/templates/story/story.php?storyId=120545...
https://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/...
There are different kinds of MRIs, but the actual direct costs for running an MRI without preparatory procedures is around $100 (preparatory dye injection may be another $50 cost). Marginal costs are lower still.
See also here:
https://www.npr.org/templates/story/story.php?storyId=120545...
https://www.pbs.org/wgbh/pages/frontline/sickaroundtheworld/...
If you would like a $100 scan, you can do it in Romania.
<http://www.hiperdia.ro/servicii-medicale/>
It's a modern 1.5T MRI.
<http://www.hiperdia.ro/servicii-medicale/>
It's a modern 1.5T MRI.
I am actually an MD.
> Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree
How, pray tell, are we actually determining which are malignant and which are not?? I’ll give you a hint: the charitable explanation is you are completely ignorant, the less charitable one is that you consider Mengele and Ishii modern medicine heroes. And that is even if the determination by imaging alone is even possible.
Once again I have to point out on HN... not everyone in the medical world is an idiot incapable of analytical thinking, it is just that a lot of us care about ethics. Our patients, even in research, are more than just numbers.
> Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree
How, pray tell, are we actually determining which are malignant and which are not?? I’ll give you a hint: the charitable explanation is you are completely ignorant, the less charitable one is that you consider Mengele and Ishii modern medicine heroes. And that is even if the determination by imaging alone is even possible.
Once again I have to point out on HN... not everyone in the medical world is an idiot incapable of analytical thinking, it is just that a lot of us care about ethics. Our patients, even in research, are more than just numbers.
I don't even think it's about the ethics that necessarily make this statement wrong (though, you are correct in that HN needs to consider basic ethics on a much more frequent basis).
In the case of these detections, the ground truth can be very subjective and is certainly not a simple explanation. Is the ground truth read by a radiologist? A radiologist with fellowship training? Multiple radiologists? Biopsied? Followed for 5 years to see if the patient actually died of their tumor?
The complexity is a lot more than the underlying algorithms and computer science (though they are important!).
In the case of these detections, the ground truth can be very subjective and is certainly not a simple explanation. Is the ground truth read by a radiologist? A radiologist with fellowship training? Multiple radiologists? Biopsied? Followed for 5 years to see if the patient actually died of their tumor?
The complexity is a lot more than the underlying algorithms and computer science (though they are important!).
> How, pray tell, are we actually determining which are malignant and which are not?
When people on this forum speculate about things like this, I assume they are thinking of some future ML application. Of course you're right though, that is not doable today. The point of the OP is that if we collected more data perhaps it would be possible.
> the less charitable one is that you consider Mengele and Ishii modern medicine heroes.
The ad hominem attacks against the OP are completely unnecessary.
> I am actually an MD.
The start of your post feels like "appeal to authority."
When people on this forum speculate about things like this, I assume they are thinking of some future ML application. Of course you're right though, that is not doable today. The point of the OP is that if we collected more data perhaps it would be possible.
> the less charitable one is that you consider Mengele and Ishii modern medicine heroes.
The ad hominem attacks against the OP are completely unnecessary.
> I am actually an MD.
The start of your post feels like "appeal to authority."
> The start of your post feels like "appeal to authority."
Sounds like a declaration of fact to me
Sounds like a declaration of fact to me
What I mean is, just because the person is "actually an MD" doesn't mean the person has expertise in this specific area yet the person is using it to claim such. I.E. some might call me a computer scientist, but that doesn't mean I have enough expertise in machine learning, a sub-discipline, to say definitively that the OP's idea about using full body scan data is feasible.
Should I have started my post "I am actually a computer scientist." No, right? That would be an appeal to authority that doesn't prove I know anything about what I'm talking about. Now, if the person had started with "I am a radiologist who has looked at empirical data about full body scans versus more selective scans." that would be a more useful and valid statement.
Should I have started my post "I am actually a computer scientist." No, right? That would be an appeal to authority that doesn't prove I know anything about what I'm talking about. Now, if the person had started with "I am a radiologist who has looked at empirical data about full body scans versus more selective scans." that would be a more useful and valid statement.
It’s not a big deal. I only mentioned as a response because the op started off saying they were from a family of MDs.
Also the vast majority of practicing physicians are expected to have detailed expertise to understand the indications, application, and interpretation of imaging within their speciality. Most imaging orders are issued by medical or surgical staff, not radiologists.
Also the vast majority of practicing physicians are expected to have detailed expertise to understand the indications, application, and interpretation of imaging within their speciality. Most imaging orders are issued by medical or surgical staff, not radiologists.
My problem with your post is not that you're not a radiologist (that was just an example—and maybe I should've just written "person who has experience doing empirical studies of body scans"). It's that you use your status as "an actual MD" but that is clearly not enough and a real "appeal to authority" or "appeal to anecdotes." And then you combined that with some awful things that you compared OP to.
Looking through your post history you often jump to "appeal to authority" combined with name calling and it's a pattern that reeks of arrogance to me.
For example one of your posts starts out along the lines of, I'm not a 747 pilot, but I am a pilot... in a post about something specific to the 747 and you say the other guy was "talking out their ass." Again, not super relevant appeal to authority and some mean-spirited name calling.
> Not a 747 pilot (not sure why that matters here)... but a pilot. The flight positions are equal. The plane is designed to be flown the same from either flight position and this is routinely done. The guy saying otherwise is talking out their ass.
https://news.ycombinator.com/item?id=19675391
Another of your posts both claims you were trained as engineer and manages to call someone "full of crap" in the first two sentences.
> I personally think the gp is full of crap. I’m trained as an engineer and worked in industry a few years.
https://news.ycombinator.com/item?id=19674031
You just seem to love to tell everyone you're super special and smarter than them because of your accomplishments as a means of arguing and then put them down. It gives you instant validity to some of course, but I think it's just lazy. Your arguments should stand on their own merit. Not request to authority or anecdotes from your kind-of-related experience.
Looking through your post history you often jump to "appeal to authority" combined with name calling and it's a pattern that reeks of arrogance to me.
For example one of your posts starts out along the lines of, I'm not a 747 pilot, but I am a pilot... in a post about something specific to the 747 and you say the other guy was "talking out their ass." Again, not super relevant appeal to authority and some mean-spirited name calling.
> Not a 747 pilot (not sure why that matters here)... but a pilot. The flight positions are equal. The plane is designed to be flown the same from either flight position and this is routinely done. The guy saying otherwise is talking out their ass.
https://news.ycombinator.com/item?id=19675391
Another of your posts both claims you were trained as engineer and manages to call someone "full of crap" in the first two sentences.
> I personally think the gp is full of crap. I’m trained as an engineer and worked in industry a few years.
https://news.ycombinator.com/item?id=19674031
You just seem to love to tell everyone you're super special and smarter than them because of your accomplishments as a means of arguing and then put them down. It gives you instant validity to some of course, but I think it's just lazy. Your arguments should stand on their own merit. Not request to authority or anecdotes from your kind-of-related experience.
> How, pray tell, are we actually determining which are malignant and which are not??
A biopsy? Whichever method you would normally use to find this out?
You could even ignore all the information and just train your algorithm on whether the patient died in the next 5 years (after the scan/s).
Obviously you need data before you can determine anything automatically. But I don’t think everyone would be averse to this even if you do tell them it might be more likely to kill them due to excessive testing.
A biopsy? Whichever method you would normally use to find this out?
You could even ignore all the information and just train your algorithm on whether the patient died in the next 5 years (after the scan/s).
Obviously you need data before you can determine anything automatically. But I don’t think everyone would be averse to this even if you do tell them it might be more likely to kill them due to excessive testing.
Had we enforced a full-body MRI for every patient, we would quickly amass enough imaging data to know which anomalies are malignant and which are not to a very high degree
For those interested, I have posted a relevant screening-exam paper on the main thread that asks the question, "what do we find if we scan the brains of 2000 people?":
https://news.ycombinator.com/item?id=19965095
https://news.ycombinator.com/item?id=19965095
It's just more profitable to fob off patients as fast as you can, good for business.
In-depth investigations have massive opportunity costs for someone reimbursed on piece-work basis, takes up way too much time.
In-depth investigations have massive opportunity costs for someone reimbursed on piece-work basis, takes up way too much time.
Then more money needs to be charged or a refusal to perform them.
It is so much more efficient to tell people to go home and rest. That way you can triple book and make 3x the money.
Insurance reimbursement is exactly the same for your appointment, regardless if the patient lives or dies, or even gets correct diagnosis, nevermind correct tests.
/s
Insurance reimbursement is exactly the same for your appointment, regardless if the patient lives or dies, or even gets correct diagnosis, nevermind correct tests.
/s
I've heard this many times before and don't doubt thats the way doctors feel but it's a little like not monitoring production because you don't want developers chasing down minor production issues.
Except there's an entire literature of false positives and the costs associated with these detections [1]. Costs here include not only direct financial costs of potentially unnecessary surgical procedures, but include everything to additional complication due to treatment and patient emotional grief/loss of earnings due to aggressive care.
The lesson a lot of people who are not familiar with public health is that you need to sorta take the long view for these things since we don't make rational decisions.
To bring back your analogy, it's then sorta like requiring an all hands meeting every time your IDE catches a typo. It's still monitoring a something that MAY cause a problem in the future, but to a good enough degree the costs associated with monitering may not be relevant to your actual end goals.
[1]. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079487/
The lesson a lot of people who are not familiar with public health is that you need to sorta take the long view for these things since we don't make rational decisions.
To bring back your analogy, it's then sorta like requiring an all hands meeting every time your IDE catches a typo. It's still monitoring a something that MAY cause a problem in the future, but to a good enough degree the costs associated with monitering may not be relevant to your actual end goals.
[1]. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3079487/
[deleted]
MDs are idiots in this regard. Mainly because they've been thought medicine by other idiots. They have this stupid idea that "too much data" is bad, also stuff being a sign that you're a bad doctor if you order too much tests etc. It's a whole can of worms of crappy rationalizations here, that also hides the fact that doctors are not capable or trained to correctly deal with large volumes of data, so they know they will make mistakes that they will be liable for if they are handed more data!
More data is always better. Period.
Problem is that we lack some kind of protocols of "calculated ignorance" that they could follow, like be allowed to ignore large classes of semi-normal findings that would show up often and lead people on wild goose chases, and be safe from malpractices and stuff if they follow this "calculated ignorance". This is because in the end medicine is not about doing "the best thing at all cost", but at doing the best thing that can be done at population scales, under limits of financial cost and "comfort cost" (there are limits after most of us would prefer (high risk of) death instead of further investigations and treatments and these limits vary (wildly) by individual).
There's two things that should be drilled down into the heads of all domain experts: (1) more data is always better, and (2) it's ok to ignore as much of the data as you want if it doesn't make sense cost-wise to investigate it further. But it's always better to fish in a larger lake!
More data is always better. Period.
Problem is that we lack some kind of protocols of "calculated ignorance" that they could follow, like be allowed to ignore large classes of semi-normal findings that would show up often and lead people on wild goose chases, and be safe from malpractices and stuff if they follow this "calculated ignorance". This is because in the end medicine is not about doing "the best thing at all cost", but at doing the best thing that can be done at population scales, under limits of financial cost and "comfort cost" (there are limits after most of us would prefer (high risk of) death instead of further investigations and treatments and these limits vary (wildly) by individual).
There's two things that should be drilled down into the heads of all domain experts: (1) more data is always better, and (2) it's ok to ignore as much of the data as you want if it doesn't make sense cost-wise to investigate it further. But it's always better to fish in a larger lake!
More data is not always better. The collection process itself can be dangerous or unpleasant for the patient.
Several years ago I worked on a study looking at the spread of bacterial lung infections in long term hospital patient. In order to get the data, we would have to intubate patients that did not need it. In this case, the people who approve these studies rightfully ruled that getting that data would be too painful for the patients to allow.
Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course).
Several years ago I worked on a study looking at the spread of bacterial lung infections in long term hospital patient. In order to get the data, we would have to intubate patients that did not need it. In this case, the people who approve these studies rightfully ruled that getting that data would be too painful for the patients to allow.
Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course).
> The collection process itself can be dangerous or unpleasant for the patient.
That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous.
> Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course).
Both need to be judged on time and cost, but only the biopsy needs to be weighed against risk, not the scan. If people see a scan with anomalies and want dangerous procedures even if the risk is not demonstrated that is a cultural, education, and legal problem. Both for doctors wanting to avoid malpractice ordering unjustified tests, and for patients “wanting it out”.
But if the scan can demonstrate some marginal elevated risk, not the need for immediate intervention but for increased screening, that data could potentially save many lives, and it should be used, not hidden away because of the possibility of overreaction. Researchers need to find how best to use the data and patients and doctors need to be educated in our current best understanding, not pandered to.
That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous.
> Biopsies caused by benign findings from a full body scan are not without pain, emotional distress, risk or cost to the patient. Period. It must be weighed against the benefit that the patient would recieve (all in the aggregate, or course).
Both need to be judged on time and cost, but only the biopsy needs to be weighed against risk, not the scan. If people see a scan with anomalies and want dangerous procedures even if the risk is not demonstrated that is a cultural, education, and legal problem. Both for doctors wanting to avoid malpractice ordering unjustified tests, and for patients “wanting it out”.
But if the scan can demonstrate some marginal elevated risk, not the need for immediate intervention but for increased screening, that data could potentially save many lives, and it should be used, not hidden away because of the possibility of overreaction. Researchers need to find how best to use the data and patients and doctors need to be educated in our current best understanding, not pandered to.
> but only the biopsy needs to be weighed against risk, not the scan.
You're setting an arbitrary boundary because you don't want to consider the downsides. If you set the same boundary on the benefits of the MRI, then you wouldn't be able to include treatment of cancer as part of the upside to doing an MRI scan.
Doctors are far wiser about these things than HN commenters that have never dealt with the complex tradeoffs of dealing not only with populations of people, but also with dealing with the psychology of humans beyond people that prioritize rationality over everything else.
Doctors are responsible for treating all of humanity, not just the subset that behave the way we want them to.
You're setting an arbitrary boundary because you don't want to consider the downsides. If you set the same boundary on the benefits of the MRI, then you wouldn't be able to include treatment of cancer as part of the upside to doing an MRI scan.
Doctors are far wiser about these things than HN commenters that have never dealt with the complex tradeoffs of dealing not only with populations of people, but also with dealing with the psychology of humans beyond people that prioritize rationality over everything else.
Doctors are responsible for treating all of humanity, not just the subset that behave the way we want them to.
People can (and did) make the same case against the thermometer.
In medicine, there are physically harmless tests that can still cause harm. Full body scans are one of them. If something is found, it will likely have an emotional impact on the patient. Not all people are equally rational. Not all people have a good grasp of the statistical nature of the findings. That applies to educated people and medical professionals who deal with this stuff everyday.
My point was not that either side was correct but rather that a simple statement like "more data is always better" is not as simple as they seem to think it is. Those of us who work in this field deal with balancing the risks as best we can so that we can detect the marginal elevated risk of something in a way so that the benefit outweighs the costs (financial, physical and emotional).
My point was not that either side was correct but rather that a simple statement like "more data is always better" is not as simple as they seem to think it is. Those of us who work in this field deal with balancing the risks as best we can so that we can detect the marginal elevated risk of something in a way so that the benefit outweighs the costs (financial, physical and emotional).
It’s perfectly reasonable not to use such a test if medical science doesn’t have strong evidence what the data means. Likely that sort of statistical evidence would require institutions with teams of researchers managing and adjusting screening campaigns rather than the judgement of an individual doctor anyway. I really can’t accept the idea though that any test which is safe, cost and time effective, and produces actionable data shouldn’t be undertaken on the basis of some other judgment of emotional state. Doctors are in no way competent to make such judgements about individuals, and even accepting the premise on the scale of population, it means pandering to ignorance and in so doing damaging people’s health. You might as well limit vaccination programmes because of anti-vaccination PR campaigns.
You are comparing a program where the benefits vastly outweigh the cost to a program where the benefit is mostly speculative and the cost known.
The cost of full body imaging is not just in the scan itself but in the procedures that follow it that require anasthesia (non-zero chance of killing the patient), cause pain and may cause secondary infection. In fact, just being in the hospital or doctors office to get the procedure has a non-zero risk to due to the concentration of sick people there.
The cost of full body imaging is not just in the scan itself but in the procedures that follow it that require anasthesia (non-zero chance of killing the patient), cause pain and may cause secondary infection. In fact, just being in the hospital or doctors office to get the procedure has a non-zero risk to due to the concentration of sick people there.
I agree in the sense that this appears to be the reality of the situation at the moment, that the benefit is speculative because of a lack of evidence for the effectiveness of either the data or our ability to interpret it. I highly doubt that will be the case in the long run, as costs come down, resolution goes up, and analysis software improves.
> That’s asinine, obviously he doesn’t mean more data is always better even if the test is invasive or dangerous.
With him classifying all MDs as idiots, no it is not asinine.
I’ve known few academic physicians that would turn down data if it can be ethically obtained.
The difference between the medical profession and, say Google, is that we as a general rule do not consider the populace one big lab to experiment on as we please. The consequences are more than a little different.
It’s not like things were always this way in medicine either.
With him classifying all MDs as idiots, no it is not asinine.
I’ve known few academic physicians that would turn down data if it can be ethically obtained.
The difference between the medical profession and, say Google, is that we as a general rule do not consider the populace one big lab to experiment on as we please. The consequences are more than a little different.
It’s not like things were always this way in medicine either.
I think the key distinction is that clinical science rather than medicine needs as much data as possible, and then medicine needs to follow clinical science.
And then, that medicine needs to become much more sophisticated in dealing with risk and uncertainty, given the absurd complexity of the problem domain. Doctors are not idiots but they are no more than human while trying to do an impossibly difficult job, and are far too cocksure given that context. They should be asking for as much help as they can get, which is not the reality of the situation. See something as simple as the resistance to checklists in surgery for example, despite the evidence.
I see your point about ethical breaches which have taken place. I would tend to think of those as abuses of power rather than coming from an ideological position, but that may not be correct. You’re certainly right about the dangers of a beta test mentality.
And then, that medicine needs to become much more sophisticated in dealing with risk and uncertainty, given the absurd complexity of the problem domain. Doctors are not idiots but they are no more than human while trying to do an impossibly difficult job, and are far too cocksure given that context. They should be asking for as much help as they can get, which is not the reality of the situation. See something as simple as the resistance to checklists in surgery for example, despite the evidence.
I see your point about ethical breaches which have taken place. I would tend to think of those as abuses of power rather than coming from an ideological position, but that may not be correct. You’re certainly right about the dangers of a beta test mentality.
>In order to get the data, we would have to intubate patients that did not need it. In this case, the people who approve these studies rightfully ruled that getting that data would be too painful for the patients to allow.
I wonder what the patients who died because they had especially fast-spreading infections whose pace was not detected quickly enough would think of these altruists' wise decision to weigh the median level of "emotional distress" more highly than their lives.
I wonder what the patients who died because they had especially fast-spreading infections whose pace was not detected quickly enough would think of these altruists' wise decision to weigh the median level of "emotional distress" more highly than their lives.
People have commited suicide because of medical test results that turned out to be wrong. A decision has to be made about how many tests are performed and under what conditions. Unfortunately, that will cause harm to people no matter where we, as a society, draw that line.
Let’s just assume for sake of argument that that is true, more data is always better. And let’s assume collecting more data is not cost prohibitive on a population scale. In the real world, physicians have a major incentive to practice defensive medicine to avoid litigation.
If you order an unnecessary test and it shows something abnormal, even though in your clinical judgement it is not likely to be worrisome, you now feel a strong impulse to spend thousands more dollars to completely rule out it’s not some 1 in a million rare cancer lest you get sued. So some systemic issues at play here, not that “doctors are idiots.”
In data science, sure more data is always better but you’re not worried that more data is going to lead you to a traumatizing malpractice lawsuit.
If you order an unnecessary test and it shows something abnormal, even though in your clinical judgement it is not likely to be worrisome, you now feel a strong impulse to spend thousands more dollars to completely rule out it’s not some 1 in a million rare cancer lest you get sued. So some systemic issues at play here, not that “doctors are idiots.”
In data science, sure more data is always better but you’re not worried that more data is going to lead you to a traumatizing malpractice lawsuit.
What about having regular full body scans and tracking any anomalies over a period of months or years? You could safely ignore anything that doesn't change, but you would immediately spot any fast growing cancers before it's too late.
> The average cost of a WB-MRI scan for NSCLC patients was £317
Wow! $3000+ here in the US. Ever get the feeling you've been cheated?
Wow! $3000+ here in the US. Ever get the feeling you've been cheated?
If you prepay, costs around $400 to $500, but that is not involving private insurance.
https://www.mdsave.com/
Not affiliated, just interesting to see prices of various diagnostics around the US.
https://www.mdsave.com/
Not affiliated, just interesting to see prices of various diagnostics around the US.
There are others that are less expensive if you do some searching, like https://radiologyassist.com/ (depending on where you live).
Also, if you call independent MRI centers they will usually give you a much lower cash price (but then insurance won't reimburse).
Another point to consider is that hospital MRIs can cost 10x (ten times) more than independent MRI centers.
And while we're talking about MRIs, it's important to mention that the safer contrast agents are the macrocyclics. Avoid the linear agents if you are concerned about possible gadolinium deposits in your brain and other organs, and potential kidney damage.
Also, if you call independent MRI centers they will usually give you a much lower cash price (but then insurance won't reimburse).
Another point to consider is that hospital MRIs can cost 10x (ten times) more than independent MRI centers.
And while we're talking about MRIs, it's important to mention that the safer contrast agents are the macrocyclics. Avoid the linear agents if you are concerned about possible gadolinium deposits in your brain and other organs, and potential kidney damage.
Regarding gadolinium, linear agents are almost never used anymore (and shouldn't be), at least in the US. Also, macrocyclics do also deposit in your brain in very small amounts, however there has never been any negative effect from this shown to date. And lastly, gadolinium is not known to cause any kidney damage. The problem in the past (in particular with linear agents) was nephrogenic systemic fibrosis, which was shown to occur in patients with pre-existing poor kidney function, probably as a result of being unable to quickly clear the gadolinium, which could then deposit in tissues. There is very little risk (if any) of NSF with newer macrocyclic agents.
I've seen Groupons for MRI scans and thought surely it must be a scam. From the reviews, sometimes they pressure you to get a package for periodic scans and use the first as a base line. But interesting indeed!
State of the art MRI machine costs $3 million up front. Would take 20 scans a week, every week, for 10 years to break even on that investment at $300 per scan. Not counting physician & staff time or cost of capital.
NHS isn't a for profit healthcare system; and they'll break even earlier on the early detection and diagnosis as since it covers you for life treating you early is less expensive then treating you later when the treatment costs would be higher.
Considerations would be different if the MRI scanner was running as for profit; or you could switch coverage so the later costs would be borne by someone else.
Considerations would be different if the MRI scanner was running as for profit; or you could switch coverage so the later costs would be borne by someone else.
treating you early is less expensive then treating you later when the treatment costs would be higher.
This is true retrospectively, for anyone who it turns out really has the disease.
But studies show that prospectively (when you don't know if somebody actually has a given disease), the cost of preventative care - including follow-up tests and unnecessary treatments - exceeds the benefit that you outlined.
EDIT: add quote to clarify what I'm responding to.
This is true retrospectively, for anyone who it turns out really has the disease.
But studies show that prospectively (when you don't know if somebody actually has a given disease), the cost of preventative care - including follow-up tests and unnecessary treatments - exceeds the benefit that you outlined.
EDIT: add quote to clarify what I'm responding to.
This is a little circular, in that we do the preventive care that we actually do is the sort that we think is effective.
If it were obvious that these whole-body scans were cost effective, the NHS would have people lining up.
If it were obvious that these whole-body scans were cost effective, the NHS would have people lining up.
Which makes sense intuitively. You're trading away risk.
For reference, I recently went to an MRI ‘center’ and their business hours are 7:30am to 10pm 7 days a week.
So, even charging $500 and booking every 30 minutes, payback on investment is much less than a year.
So, even charging $500 and booking every 30 minutes, payback on investment is much less than a year.
That sounds so ridiculous compared to Germany, where grocery stores aren’t even open 7 days a week.
Only 20 scans a week?
A scan takes 30-60 minutes. So even if they only work 8 hour days and assume an hour for lunch/flex that's 35 scans per 5 day week. If they use it on weekends at all or run it for more than eight hours, that's just gravy.
I'm not sure where you got the 20 scans a week number.
A scan takes 30-60 minutes. So even if they only work 8 hour days and assume an hour for lunch/flex that's 35 scans per 5 day week. If they use it on weekends at all or run it for more than eight hours, that's just gravy.
I'm not sure where you got the 20 scans a week number.
Yep, places I've work with have usually two shifts and at least one scan an hour. So, easily, 20 scans a day.
Because scans are not booked wall to wall every hour of every day. Needs more likely follow a poisson distribution with ample waits in between uses.
To try and pack it that densely, with the large variation in how people show up at the hospital, would cause bottlenecks and loss of service.
20 a week is a more common number for most places.
Here's actual data [1] measured on site. The usage is indeed around 50%, so the 20 is a much better answer.
[1] https://www.researchgate.net/figure/MRI-scanner-utilization-...
To try and pack it that densely, with the large variation in how people show up at the hospital, would cause bottlenecks and loss of service.
20 a week is a more common number for most places.
Here's actual data [1] measured on site. The usage is indeed around 50%, so the 20 is a much better answer.
[1] https://www.researchgate.net/figure/MRI-scanner-utilization-...
Utilization is less in a hospital, especially when you're measuring "active scanning time" and not all the time that you're really using a room. Hospitals also don't book scans so aggressively since someone might need a scan pronto- in an emergency, or near-emergency- and it can't be scheduled weeks in advance like you do in outpatient settings.
Complex cases where you need anesthesia, especially, may involve a lot of mucking about before and after the "active scanning" period, where the room is being used, but the scanner is not actively scanning anyone. Also, paediatrics cases.
Utilization is a lot higher in outpatient settings where you can line patients up and turn the room around in a few minutes.
Complex cases where you need anesthesia, especially, may involve a lot of mucking about before and after the "active scanning" period, where the room is being used, but the scanner is not actively scanning anyone. Also, paediatrics cases.
Utilization is a lot higher in outpatient settings where you can line patients up and turn the room around in a few minutes.
This is data from a hospital. In the U.S. at least, a lot of MRI scans are done in outpatient centers, scheduled well in advance, and so utilization can be much higher. This would certainly be true of prophylactic scans.
The utilization could also be much lower. If not enough people need to sign up for each and every day, then it will not be full. It's extremely unlikely the needs in a region match the capacity anywhere near 100%. Such a tight capacity would result in many problems, so reasonable planning would have excess capacity to deal with busy seasons/holidays/weekends/etc.
Just like the hospital case, things like this likely follow a Poisson distribution, and it is therefore reasonable to assume similar usage patterns.
Have a link with data for your claim? I looked and found none.
Just like the hospital case, things like this likely follow a Poisson distribution, and it is therefore reasonable to assume similar usage patterns.
Have a link with data for your claim? I looked and found none.
>Because scans are not booked wall to wall every hour of every day. //
I had a scan in the UK, and this is exactly how it was done. Mine was actually in a mobile unit set up in a car park (for several months).
It took about 20mins and I was in the ante-room getting prepped as someone else was in the scanner, someone else was in the waiting room waiting to go next. At least a couple an hour and there were a couple of shifts of workers too (I asked).
As an aside the workers were all foreign, how fortunate we were/are and how sad for those countries to lose their talent to us.
I had a scan in the UK, and this is exactly how it was done. Mine was actually in a mobile unit set up in a car park (for several months).
It took about 20mins and I was in the ante-room getting prepped as someone else was in the scanner, someone else was in the waiting room waiting to go next. At least a couple an hour and there were a couple of shifts of workers too (I asked).
As an aside the workers were all foreign, how fortunate we were/are and how sad for those countries to lose their talent to us.
A lot has changed since 2011 but even back then the MR scanner should always have been full and the next patient should have been waiting outside. If a scanner is very early or late you call the next patients and alter scheduling. Anything else is a waste of time and money.
There's a reason we design roads, electric grids, food supply, and so on, to not perfectly match needs. It's impossible and foolish to assume constant rates of needs.
For the same reason, no hospital would assume MRI scanners are 100% in use all the time. You cannot schedule people needs that perfectly without fail, on holidays, summer versus winter, day and night, weekends versus Mondays, and so on.
For the same reason, no hospital would assume MRI scanners are 100% in use all the time. You cannot schedule people needs that perfectly without fail, on holidays, summer versus winter, day and night, weekends versus Mondays, and so on.
40% utilization means that it was in use for 67 hours per week. I don't think an MRI takes three hours.
(In the case of the study listed, the utilization figures might be out of ~35 hours, which would make things different - but they also exclude scans scheduled in advance)
(In the case of the study listed, the utilization figures might be out of ~35 hours, which would make things different - but they also exclude scans scheduled in advance)
MRIs take as long as you can afford.
I have actually run ~3 hour MRIs for experiments, but we're being very fussy and trying to get the best possible image with the smallest possible voxel, which you do by acquiring tons of volumes and averaging them. Obviously, you can be in and out of there much quicker if you're just looking for a gaping hole.
I have actually run ~3 hour MRIs for experiments, but we're being very fussy and trying to get the best possible image with the smallest possible voxel, which you do by acquiring tons of volumes and averaging them. Obviously, you can be in and out of there much quicker if you're just looking for a gaping hole.
The link states "As a result, in our study the maximum hours per week on each scanner was limited to 35 h for the Vision (no hours on Tuesdays), 39 h for the Harmony, 32 h for the Sonata (no hours on Wednesdays) and 38 h for the Avanto."
Why guess 67 when you can look at the answer?
Why guess 67 when you can look at the answer?
Because from my reading that's not the number of hours they used the machines, but the number of hours in which the machines were available to be used. And since they also state that their utilization figures only include emergency cases (and exclude scheduled scans) I don't consider it a particularly relevant source in the first place.
>I don't consider it a particularly relevant source in the first place.
Care to provide a relevant source?
Care to provide a relevant source?
10-20 scans per day is a full days work in MRI for an 8-9 hour day. I’m an MR radiographer.
Yes but you don't do 20 scans a week, you do that per day
Looks like you're pretty close: https://www.radiologybusiness.com/topics/business-intelligen...
>Ultimately, UVI increased appointment slots to 407 a week, efficiency was boosted to about 82%, and it is averaging 433 examinations per week.
That's for four machines.
>Ultimately, UVI increased appointment slots to 407 a week, efficiency was boosted to about 82%, and it is averaging 433 examinations per week.
That's for four machines.
Isn't 20 scans a day something like 15 hours of continuous, back-to-back scanning?
Are you saying that you wouldn't have your multi-million dollar imager running as much as possible?
I'm saying that it seems like a most optimistic, best-case scenario, and not the average case.
When my partner needed an outpatient MRI, we got it done the next day by accepting the 11pm time slot. This was at a private hospital in Australia in 2006. We were super impressed by everything that department did to maximise utilisation. It was like a production line!
Some scans are very fast. For a basic knee scan done well it’s 10-15 minutes of imaging time and lumbar spine scans are a couple of minutes longer. With 2 staff the changeover can be a minute of 3. With good scheduling the scans that are similar are booked back to back and equipment changes are minimal.
My insurer pays like $450. The hospitals seem to be doing ok, if anything there are way too many MRIs out there.
A few years back that was the "japanese problem": the price of MRI machines started falling but the act itself (whose price is set by policy / negotiations) hadn't been revised yet, so every clinic started getting one, which contributed to the price falling, and a price revision or two later the price was revised to ~$100, but the cheap MRIs and habit to use them remained.
We're talking circa 2010, around the time of the obamacare debate in the US.
We're talking circa 2010, around the time of the obamacare debate in the US.
Well if you are not including external costs, you can get a MRI machine at around $100k to $500 depending on your needs[0].
[0]:https://www.alibaba.com/product-detail/IN-16CT-Hospital-Medi...
[0]:https://www.alibaba.com/product-detail/IN-16CT-Hospital-Medi...
Not only that, but it's also an X-Ray and CT scanner. What a bargain!
In all seriousness the product linked is a CT scanner, which are way less expensive in general.
In all seriousness the product linked is a CT scanner, which are way less expensive in general.
Not all MRI machines are equal, though, so it's hard to tell without specifics.
A low field 0.2T machine might be $150k. A full bells+whistles 3T machine might be $3M.
A low field 0.2T machine might be $150k. A full bells+whistles 3T machine might be $3M.
1.5T or 3T is where imaging gets useful and then you’re back at the high end of the pricing.
Don't forget the price increase when the MR software developers sprinkle in the machine learning pixie dust!
(Source: am a MR software developer)
(Source: am a MR software developer)
I’d love there do be more interaction between radiographers and devs. There are some strange bugs on all the major platforms (my GE experience is now probably too old to be relevant) and removing them would be so excellent.
What is your area/role?
Without outing my specific company and location: I do primarily operating system and associated plumbing level development for a platform supporting MR applications as well as some application work atop that.
The 'bells and whistles' model is starting to move to 7T, and the price scales accordingly.
I've had this idea floating in my head for a while. Provide free annual full body MRIs to people, including being read by a radiologist, which they can take to anyone they want (doctor, lawyer, whatever). In exchange, they agree to send the org a copy of all their past and future medical records. The records are anonymized and tied to the MRIs.
The MRIs and medical data is then pumped through machine learning algorithms to attempt to identify early signs of disease. The data of course would be most useful to future people, because we won't know someone has something until a doctor diagnoses it, but if the AI model can look at the MRI from five years ago on everyone with disease X and find a common early warning sign, then we could apply it to future cases where it might be possible someone has X and catch X much earlier.
Basically, I want to create a charity that gives free full body MRIs in exchange for a bunch of medical data for training an AI.
The MRIs and medical data is then pumped through machine learning algorithms to attempt to identify early signs of disease. The data of course would be most useful to future people, because we won't know someone has something until a doctor diagnoses it, but if the AI model can look at the MRI from five years ago on everyone with disease X and find a common early warning sign, then we could apply it to future cases where it might be possible someone has X and catch X much earlier.
Basically, I want to create a charity that gives free full body MRIs in exchange for a bunch of medical data for training an AI.
That's not a charity, it's the good ole model of paying with data.
You might as well show ads to the patients while they're in the machine and evaluate their brainwaves to see which they like best.
You might as well show ads to the patients while they're in the machine and evaluate their brainwaves to see which they like best.
Except no profit would be made on data. All the findings would be given away for free. So we'd need donations to pay for the machine, its upkeep, and the staff to run it.
So not really anything like the pay with data model.
So not really anything like the pay with data model.
I've had the same idea for a long time, and I'd also like to see a charity start doing this. It's crazy that so many people are saying this is a bad idea. I think it has the potential to save millions of lives.
I was very tempted to join an AI startup in a similar space, but I decided to turn down their offer because they were a for-profit company, and that just didn't feel right. The offer was also too low, but I would have probably joined if they were a non-profit.
I was very tempted to join an AI startup in a similar space, but I decided to turn down their offer because they were a for-profit company, and that just didn't feel right. The offer was also too low, but I would have probably joined if they were a non-profit.
Not to be too snarky, but...you know about universities right?
I can almost guarantee there's a university or research institute near you doing some kind of research that's trying to improve or understand human health via MRI.
I can almost guarantee there's a university or research institute near you doing some kind of research that's trying to improve or understand human health via MRI.
I actually never considered working with universities. I'm not too sure what that would look like.
My plan was to start a non-profit organization and hire some radiologists, AI experts, and software engineers. I would also need a lot of help from lawyers and healthcare experts to make sure we're complying with laws and regulations. Then I wanted to purchase a few second-hand MRI machines and start a pilot program somewhere.
I would probably start in New Zealand (my home country), and then move to other countries with universal healthcare (Australia, Canada, UK.) Early detection of cancer should end up saving a lot of money (compared to treating cancer in the later stages), so in the future it should be possible to get government funding that covers the entire program.
I'm not too interested in starting a for-profit company, but it's probably the only way to do something in the US. So I'd leave that to someone else.
But yes, it definitely makes sense to work with a university or hospital. Maybe the Centre for Advanced MRI at Auckland University [1].
(P.S. This is just a project I would want to tackle if I ever sell a company and end up with a ton of money. There's no chance that I'll be doing something soon.)
[1] https://www.fmhs.auckland.ac.nz/en/faculty/camri.html
My plan was to start a non-profit organization and hire some radiologists, AI experts, and software engineers. I would also need a lot of help from lawyers and healthcare experts to make sure we're complying with laws and regulations. Then I wanted to purchase a few second-hand MRI machines and start a pilot program somewhere.
I would probably start in New Zealand (my home country), and then move to other countries with universal healthcare (Australia, Canada, UK.) Early detection of cancer should end up saving a lot of money (compared to treating cancer in the later stages), so in the future it should be possible to get government funding that covers the entire program.
I'm not too interested in starting a for-profit company, but it's probably the only way to do something in the US. So I'd leave that to someone else.
But yes, it definitely makes sense to work with a university or hospital. Maybe the Centre for Advanced MRI at Auckland University [1].
(P.S. This is just a project I would want to tackle if I ever sell a company and end up with a ton of money. There's no chance that I'll be doing something soon.)
[1] https://www.fmhs.auckland.ac.nz/en/faculty/camri.html
The thing you're describing is almost exactly a university medical center: a non-profit staffed with doctors and researchers running research projects. They also have the technical and administrative staff to run them properly.
Most professors at a medical school don't lecture very much, but are instead responsible for running research programs like the one you're describing. They either do this on their own, or as part of bigger consortiums. I'm mostly interested in brain stuff, where there are some big imaging+analysis collaborations. The Human Connectome Project collected about 1200 subjects' MRIs, plus a bunch of related health data. The Alzheimer's Disease Neuroimaging Initative is doing something similar, with a focus on neurodegeneration. I would imagine there are similar ones for the rest of the body.
Most people start on these projects as grad students, coming from biomedical programs (Neuro, Bio, Psych), engineering, physics, CS, or even math, depending on exactly what you want to do. There are other career tracks though--some people get hired on as research assistants or staff programmers, either attached to large programs or as permanent staff at big universities or institutes. These positions are a little harder to find, especially since RA can mean anything from "will train" to "needs PhD + 5 years experience". They often pay a bit better (though not tech industry levels), but have a bit less freedom.
The US actually funds a ton of biomedical research through the NIH (and NSF and DARPA), and is probably one of the better bets for running large, expensive studies.
Most professors at a medical school don't lecture very much, but are instead responsible for running research programs like the one you're describing. They either do this on their own, or as part of bigger consortiums. I'm mostly interested in brain stuff, where there are some big imaging+analysis collaborations. The Human Connectome Project collected about 1200 subjects' MRIs, plus a bunch of related health data. The Alzheimer's Disease Neuroimaging Initative is doing something similar, with a focus on neurodegeneration. I would imagine there are similar ones for the rest of the body.
Most people start on these projects as grad students, coming from biomedical programs (Neuro, Bio, Psych), engineering, physics, CS, or even math, depending on exactly what you want to do. There are other career tracks though--some people get hired on as research assistants or staff programmers, either attached to large programs or as permanent staff at big universities or institutes. These positions are a little harder to find, especially since RA can mean anything from "will train" to "needs PhD + 5 years experience". They often pay a bit better (though not tech industry levels), but have a bit less freedom.
The US actually funds a ton of biomedical research through the NIH (and NSF and DARPA), and is probably one of the better bets for running large, expensive studies.
> annual full body MRIs to people
So, these are not medically indicated scans which means you're going to be causing huge amounts of over-diagnosis and thus over-treatment, which cause harm.
Hypothetical Bob has his first scan, and it returns a few shadows on his lung. The doctors ask if he's ever had chicken pox and he doesn't think so but he's not sure. So, these shadows are probably just scaring from chicken pox. But maybe they're cancer. The only sure way to tell is for a biopsy. Every medical intervention carries risk, and because you've increased the numbers of interventions you've increased the numbers of people falling victim to that risk.
Bob got a scare; he got an unnecessary medical intervention; he was subjected to risk: what did Bob gain from this?
The only thing this extra data tells us is "chicken pox sometimes scars the lungs and they sometimes show up on MRI", which is something we already know.
You do have a good point about the difficulty in getting hold of data to train AI. Sadly, because of recent missteps in England that's going to continue to be difficult unless the company can show rigorous protections.
So, these are not medically indicated scans which means you're going to be causing huge amounts of over-diagnosis and thus over-treatment, which cause harm.
Hypothetical Bob has his first scan, and it returns a few shadows on his lung. The doctors ask if he's ever had chicken pox and he doesn't think so but he's not sure. So, these shadows are probably just scaring from chicken pox. But maybe they're cancer. The only sure way to tell is for a biopsy. Every medical intervention carries risk, and because you've increased the numbers of interventions you've increased the numbers of people falling victim to that risk.
Bob got a scare; he got an unnecessary medical intervention; he was subjected to risk: what did Bob gain from this?
The only thing this extra data tells us is "chicken pox sometimes scars the lungs and they sometimes show up on MRI", which is something we already know.
You do have a good point about the difficulty in getting hold of data to train AI. Sadly, because of recent missteps in England that's going to continue to be difficult unless the company can show rigorous protections.
> So, these are not medically indicated scans which means you're going to be causing huge amounts of over-diagnosis and thus over-treatment, which cause harm.
What if we did something like set up a system where Bob's doctor can put in other symptoms, and only if one shows up that would indicate a lung MRI would the doctor be told, "Oh hey, we already did that, here's the MRI, and there was some shadow on the lung"?
What if we did something like set up a system where Bob's doctor can put in other symptoms, and only if one shows up that would indicate a lung MRI would the doctor be told, "Oh hey, we already did that, here's the MRI, and there was some shadow on the lung"?
> agree to send the org a copy of all their past and future medical records..
Even ignoring the issue of false positives, which alone is serious enough to make this a dubious idea... that is an extreme thing to ask of people. All my future records? I have no idea what my future holds, and what I may feel about that as I age and experience new problems. Nor how my family might feel about it on my deathbed.
I applaud new ways to for early detection of problems, but not like this.
Even ignoring the issue of false positives, which alone is serious enough to make this a dubious idea... that is an extreme thing to ask of people. All my future records? I have no idea what my future holds, and what I may feel about that as I age and experience new problems. Nor how my family might feel about it on my deathbed.
I applaud new ways to for early detection of problems, but not like this.
Well if you didn't like the terms you wouldn't have to get your free scan. :) I hear where you're coming from, but the data isn't nearly as useful if we don't get to find out what diseases you get later in life. The whole point is to train an AI so we need the future data to make it work.
My wife has had full body scans every 3 months for the past 3 years. She currently has multiple active sites of bone mets, from the spine to shoulders and hips. A single scan is much more convenient and keeps the oncologist up to date with the state of her cancer.
In our experience sometimes a new cancer site isn't diagnosed quickly, especially if it's asymptomatic and slow growing. Having past scans and reviewing them overtime has found multiple tumors so far.
Seems the radiographers err on the side of caution when feeding back to the Oncologist. Her last cancer in her neck (c2) had been tracked over 3 scans (because it was small and slow growing), before it was reported back to us and subsequently treated with cyberknife.
In our experience sometimes a new cancer site isn't diagnosed quickly, especially if it's asymptomatic and slow growing. Having past scans and reviewing them overtime has found multiple tumors so far.
Seems the radiographers err on the side of caution when feeding back to the Oncologist. Her last cancer in her neck (c2) had been tracked over 3 scans (because it was small and slow growing), before it was reported back to us and subsequently treated with cyberknife.
What's the primary Cancer type? I'm assuming multiple myeloma?
Breast Cancer HER2+ Currently being treated with Trastuzumab and Pertuzumab every 3 weeks. Seems to be doing its job keeping down the cancer growth rate. She also used to have Zoledronic acid at the same time but that caused osteonecrosis of the jaw, so has been stopped.
Strangely, we're relatively happy with the bone mets. The two times the cancer hit soft tissue it grew alarmingly quickly. First in the breast, then when it came back and broke out the L2 vertebrae and wrapped the nerve. At least in the bone it grows slowly. When it eventually starts to break out, the next treatment is Trastuzumab emtansine, which is a chemo drug, so will have many more side effects to manage.
Strangely, we're relatively happy with the bone mets. The two times the cancer hit soft tissue it grew alarmingly quickly. First in the breast, then when it came back and broke out the L2 vertebrae and wrapped the nerve. At least in the bone it grows slowly. When it eventually starts to break out, the next treatment is Trastuzumab emtansine, which is a chemo drug, so will have many more side effects to manage.
I'm curious what affects this will have on false diagnosis and well...patient sanity. It seems like the majority of people have some sort of benign growth: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5008738/
MRI are generaly considered safe but my personnal experience contradict this. I passed a 3T brain MRI (with gadolinium injection for angiography) ~80 days ago and my life has been seriously painful since then. I have experienced hypertension (often >170 of systole, seem unrelated but never had high tension of my life and like the rest of theses issues it appeared exactly after the MRI), sleep issues, head difficulties to think and head "rigidity", sexual/erectile disfunction (other side-effets started to dim a bit since then, but not this one), continuous heat on of my face up to 3 weeks after the exam. I am not trying to spread FUD but this has unfortunately been my experience. I'm a fragile kind of person, though I didn't expected it would be (so) unsettling. YMMV but you may reconsider passing one if you don't have confidence it would help you diagnosis or find issues (stenosis, neoplasm...).
Make sure you report this to both your GP and to the company that makes the machine. All major MRI machine makers watch for adverse reactions like hawks, and if there's any way that your experience is an adverse reaction to either the contrast or the scan they are going to want the details to prevent it from happening to somebody else.
Thanks for the advice, I will send an email to GE.
GE's hotline for suspected adverse reactions is 1-800-654-0118
You can also report to the FDA at 1-800-FDA-1088
(Both of these were the third hit searching for 'report ge mri adverse reactions' on Google.)
You can also report to the FDA at 1-800-FDA-1088
(Both of these were the third hit searching for 'report ge mri adverse reactions' on Google.)
Friend of mine recently got diagnosed with cancer. Has over a dozen golf-ball sized tumors in his brain, bones, lungs, liver, etc. After 6 months of nagging pain and pneumonia they finally did a small MRI and saw something odd. Then they did a full-body MRI and it was very very obvious.
Taking an image can help catch things? No shit Sherlock! I don't care if doctors can't agree imaging diagnoses sometimes. Time to get better at doing that. Computers can help. Yes there's a helium shortage, but since when does healthcare get short-changed?
Aside: there's at least one company looking to make whole-body imaging more available: https://q.bio/ The founder is a little crazy, but a good kind of crazy.
Taking an image can help catch things? No shit Sherlock! I don't care if doctors can't agree imaging diagnoses sometimes. Time to get better at doing that. Computers can help. Yes there's a helium shortage, but since when does healthcare get short-changed?
Aside: there's at least one company looking to make whole-body imaging more available: https://q.bio/ The founder is a little crazy, but a good kind of crazy.
Here's the NIHR blog: https://www.nihr.ac.uk/blogs/does-how-we-detect-the-spread-o...
And here's the paper: https://www.journalslibrary.nihr.ac.uk/programmes/hta/106801...
These are worth reading, they're in more detail than the submitted site. I recommend NIHR because they're usually short and very readable.
And here's the paper: https://www.journalslibrary.nihr.ac.uk/programmes/hta/106801...
These are worth reading, they're in more detail than the submitted site. I recommend NIHR because they're usually short and very readable.
With sufficient software and computational horsepower, a single whole-body MRI could replace most diagnostic imaging systems, I'd wager. Computer models regularly outperform radiologists in diagnosing several conditions involving structural abnormalities.
Gonna have a hard time with bones....
On to driving down the cost of MRIs and eliminating their need for helium.
Phillips and GE both have new models that use a lot less (10-20L vs. 1000L) of helium. I think they're only 1.5T though.
The Phillips model is called "BlueSeal"; I can't remember GE's, but it's something goofy.
The Phillips model is called "BlueSeal"; I can't remember GE's, but it's something goofy.
GE's name for this tech is Freelium[1].
[1] https://www3.gehealthcare.com/~/media/rsna-2016-press-kit-as...
[1] https://www3.gehealthcare.com/~/media/rsna-2016-press-kit-as...
Yes! Thanks! (I knew it was slightly goofy)
CT scans still have higher resolution than MRI for certain vascular and cardiac imaging studies. The down side is radiation exposure.
The new digital CTs are crazy.
We have one that goes down to 90 µm resolution for the whole head.
We have one that goes down to 90 µm resolution for the whole head.
they could still probably do a whole hell of a lot better with automated diagnosis.
> preferred by patients and involving less exposure to radiation
I thought MRIs didn't have any radiation exposure as opposed to X-Rays and CT scans; unsure about this benefit of less exposure to radiation from 1 whole-body MRI vs multiple MRIs (should be the same IMO)
I thought MRIs didn't have any radiation exposure as opposed to X-Rays and CT scans; unsure about this benefit of less exposure to radiation from 1 whole-body MRI vs multiple MRIs (should be the same IMO)
Not the greatest article. From another one:
"Standard NHS pathways often involve different imaging techniques - such as CT, PET-CT or focused MRI scans - which vary in accuracy in different organs."
... so they do targeted scans (with radiation risk) as their normal practice. That kind of makes sense, since the resolution of those scans is much better than WB-MRI.
... so they do targeted scans (with radiation risk) as their normal practice. That kind of makes sense, since the resolution of those scans is much better than WB-MRI.
What is the state of cancer detection through blood samples?
There are some cancers where blood biomarkers give us more information than others, but save for leukemia, I'm unaware of any that are sufficient for diagnosis.
While still widely, the effectiveness of some blood biomarkers like PSA (prostate cancer) can be controversial.
So, while I could be wrong since this isn't my area of expertise, there's a long way to go for most cancers when it comes to blood testing.
While still widely, the effectiveness of some blood biomarkers like PSA (prostate cancer) can be controversial.
So, while I could be wrong since this isn't my area of expertise, there's a long way to go for most cancers when it comes to blood testing.
The buzzword you want is 'liquid biopsy', though the results are currently underwhelming.
How can I get a full body exploratory MRI done? Is this even possible? I've tried bribing with tens of thousands of dollars and I still get denied.
If you're likely to benefit from one (e.g., you had cancer), your doctor should be able to make that happen. Otherwise, it's unlikely to do much for your health.
If you're just curious to see what your own brain (liver, etc) looks like, you might want to volunteer for a study at a local university and ask them if you can get a copy of your own scan. I know one lab that will even show you how to 3D print your brain, if you want.
If you're just curious to see what your own brain (liver, etc) looks like, you might want to volunteer for a study at a local university and ask them if you can get a copy of your own scan. I know one lab that will even show you how to 3D print your brain, if you want.
Someone should start a 23andMe but for whole body MRIs (To be clear: I'm kidding, this is a joke and a terrible idea.)
i actually did this a month ago. found no cancer but some surprises that i have had to react to... you have to be very careful because they can pick up irrelevant stuff, but i think this will be a huge field in the future.
There is no mentioning of exposure during MRIs. Is there none? I would have thought, CTs as well as MRIs are a problem because of exposure.
Because CT scans and MRI scans are very different technologies....
CT = xray
MRI = Magnetic resonance imaging
There is no exposure in an MRI to radiation. The only danger would be having bits of metal on you or inside you.
CT = xray
MRI = Magnetic resonance imaging
There is no exposure in an MRI to radiation. The only danger would be having bits of metal on you or inside you.
Specifically ferromagnetic metal. Surgical implants are largely okay, but there are some neurostimulators that can be a problem.
I have a hard time with reporting like this that doesn't quantify cost of biopsy on false-positives as well as cost of complications from examining false-positives.
Source: worked in clinical research for 2 years.