Lasik and discrete MRIs are really awful examples. The former is elective, the latter is an oddball.
In reality one needs to shop around for the things that happen after the positive MRI such as the radiologist who reads the MRI, physical therapy, medications, anesthetist, recovery room, OR, OR supplies, recovery room supplies, expendable surgical device costs, and a mass of other things I forgot about even though I just had one of these.
Everything is itemized and the actual end cost cannot practically be shopped.