There are some non-ML based approaches for ultra low field MRI that are starting to work: https://drive.google.com/file/d/1m7K1W--UOUecDPlm7KqFYzfkoew... . You can still add AI on top of course, but at least you get a better signal to noise ratio to start with!
Zama uses TFHE, which allows any operation (eg comparisons) with unlimited depth.
So if you only need add/mul, BFV, BGV and CKKS are good options. For anything else, you better use TFHE