IThey can't even be sure after the MRI. Which again, proves your point. It took one MRI battery and one alert and skilled MRI tech to catch my brain cyst, THEN another whole set, I straight up spend a whole 8hr shift in an MRI machine, Then a TEAM of neurologists studied my custom hand made brain for MONTHS. THEN they had a really good set of educated guesses. Then they did the surgery, and only after they opened up my brain case did the actually see what in the hell was going on. Even after all that, my neurologists was like ''This is what we think is happening'', I asked what it would take to really know factually, he said an autopsy. He didn't recommend it. The point is, Doctors save lives with these scans, and nothing is certain. That's not a barrier to treatment, but no scans Is a barrier to treatment.