I’m fascinated. What makes a great radiologist so much better than the average?

Calling the edge cases correctly, I would think.

I hurt my arm a while back and the ER guy didn't spot the radial head fracture, but the specialist did. No big deal since the treatment was the same either way.

Im not the OP and I’m an MR tech.

I rate techs against non-radiology trained physicians in terms of identifying pathology. However techs aren’t anywhere near the ability of a radiologist.

Persuading junior techs not to scan each other and decide the diagnosis is a reoccurring problem, and it comes up too often.

These techs are trained and are good. I have too many stories about things techs have missed which a radiologist has immediately spotted.

You're specifically trained to look at the scans, and not to do 75 other things as well, only to use scans to aid your whatever you're doing.