Even with the best, most efficient search pattern, as a mere mortal one is not going to be 100-percent attentive to and appreciative of every little detail as one’s eyes pass over it. Missing or misinterpreting an abnormality, or failing to recognize a pertinent negative that would rule out a particular diagnosis, is to be expected.
It’s happened more than once to me that I briefly mistook a prominent wave — or a rock just breaking the water’s surface — as my very own sighting. Then, even when I recognize my error, I, not uncommonly, continue to scan the area because some part of my brain isn’t quite ready to let go of it. I’ve done the same with imaging “lesions.” I thought I saw something in the liver, realized there wasn’t anything there…but I go back and look in the area a few more times before I sign off and close the case.
The observer (rad, whale-watcher, or whatever else) is also not the only factor. Just as a whale-watching boat might not happen to be in the right place at the right time, maybe the imaging study that was ordered by the referrer wasn’t the best modality to use, or it focused on the wrong body part as result of referred symptoms. Maybe the study was ordered when the patient was having symptoms two weeks ago, but he’s since recovered, and now there’s nothing to see. And, of course, technical limitations on studies have been known to impair our diagnostic work.
But, when we do make a diagnostic difference—just like happening to see a whale poke its head above water to “spyhop”—that can more than make up for the boredom, even frustration of having searched fruitlessly on other cases for half of the day thus far. It’s why many of us got into this biz in the first place, and hitting a little paydirt goes a long, satisfying way.