Call Them All Normal

May 2, 2013

These days it’s getting harder to wade through all the negatives to find the positives, and there’s less incentive to do so.

“Kill them all and let God sort them out.”

This is a now-famous paraphrasing of a statement attributed to Arnaud Amalric in 1209 outside Beziers, France. Pope Innocent III had dispatched an army under the command of Simon de Montfort to get rid of the heretic Christian sect known as the Cathars. They peacefully coexisted as a minority group in the town of Beziers when the Pope’s army showed up. Since the Cathars were indistinguishable from the innocent townspeople, a soldier asked Amalric, the Pope’s representative, how they were supposed to know who to kill. Amalric reportedly said, “Kill them all. God will recognize his own.”

Fast forward about 770 years.

When I arrived in West Virginia I began to hear tales of a radiologist who apparently marched to a different drummer. This long-haired, bearded, hippy reportedly always smelled faintly of marijuana and lived a rather unorthodox lifestyle. One of his eccentricities was his transportation. Apparently, he had a number of vehicles parked in his yard and would chose his transportation du jour based on which one would start that day.

One of my partners told me he met with him once at RSNA. They talked for about an hour about a potential job and my friend thought no more about it until he returned home, and one day, a few weeks later, he received a call from said hippy radiologist. He said he had found my friend’s card in his jacket pocket and wondered if he was supposed to call him. So much for lasting impressions or perhaps too much self-medication.

As might be expected, this radiologist’s attitude toward radiology was also a bit unorthodox. He is credited with the theory that if you read all studies as normal, you will only miss about 10 percent or so of the cases. In his opinion, this was an acceptable miss rate.

Naturally, I was shocked and deeply offended when I heard this. On deeper reflection many years later, I think he may have been on to something.

In those days most studies only had a few images - 10 to 20 at most. Nowadays, studies can have hundreds of images and multiple studies on a patient can number a few thousand images. I’m sure if you took all the positive images from these studies and divided them by the total number of images on the patient, the percentage positive would be well below 1 percent. Obviously, you can’t just call everything normal, but there are days when it is hard to wade through all the normal “chaff” to get to the abnormal “wheat.”

For instance, CT angiography for pulmonary embolism seems to have very little “bang for the buck.” In my experience there are very few positives and I wonder if the “return on investment” for this study is worth it.

I once heard a presentation about diagnosing osteomyelitis in patients with diabetic neuropathic foot disease using MRI and labeled white cell scans. The presenter’s conclusion was that it would be cheaper to just treat all of the patients with antibiotics than perform all those expensive imaging studies on them.

Naturally, there was more interest in scouring through the studies for the occasional positive when there was the possibility of getting paid for it. It is getting harder to wade through all the negatives to find the positives and there’s less incentive to do it. Perhaps God can sort it all out.