When your mind tries to verify a preconceived notion you can miss the obvious.

—James Cook

Truer words have infrequently been spoken. Going into a situation and knowing (in your own little head) what you will see can significantly influence what you really do see. The “invisible gorilla” test made that pretty clear. What’s the invisible gorilla test, you ask?

Allow me.

Test subjects were asked to watch people in contrasting gym clothing passing a ball and to count how many times players in the white shirts passed the ball. Midway through, a gorilla came into view, pounded its chest, and walked off. More than half of the observers never saw it.

Radiology angle? Oooh, too easy.

Ever look a second time at a study you (or maybe someone you know) read and see the gorilla in the first glance? Pounding its chest and daring you to miss it? You know exactly what you will do next; you will look at the report to see if the gorilla has made it there. And, sometimes, it has not.

Were you (or they) asleep? Did you have a TIA? Nope, unlikely. You might have been guided to somewhere else in the study, had a reason to question something else, were distracted, or perhaps there was an IT glitch. Who knows? But you didn’t see the gorilla.

I see enough of these to wonder if gremlins may have something to do with it. An evil influence from another dimension. Maybe something to do with the drones over New Jersey. Voodoo.

And don’t think this is unique to radiology. The cutaneous lesion, oral cavity lesion, fill-in-the-blank lesion that was overlooked or just did not reach the supra-gorilla level and slips through being seen by 10 or more well-intended clinicians. We’ve all seen those, too.

Unfortunately, you aren’t going to be forgiven for missing the gorilla. You’ve got to hope that the gorilla was innocuous, because once the gorilla is spotted, the gorilla is as conspicuous as, well, a gorilla parading amongst a few folks in shorts and t-shirts passing a ball. Some people feel it may be evolution hurting us; our eyes and brains were conditioned to things moving at lesser speeds; not hurtling down the interstate at 75 mph, piloting an aircraft flying at 500 mph, or trying to get through 1400 images in the short period of time we have allotted to read a CT. Intuition can mislead you, for sure.

Look out for the gorilla. And keep doing that good work. Mahalo.