A Game of Shadows 2

 

Shadows

A GAME OF SHADOWS, 2/3
by Edison McDaniels, MD

Dandy ultimately discovered that replacing the CSF with air, called pneumoencephalography, did a tolerable job of visualizing the ventricles and any tumor either in the ventricles or large enough to distort the ventricles (hence, most of the tumors discovered this way were quite large). Unfortunately for the patient, pneumoencephalography was a difficult and dangerous test to perform. The brain normally floats in the CSF. Removing most of the CSF for this procedure was no easy feat, and was extremely painful with severe headaches lasting days to weeks afterwards. Not to mention the nausea that accompanied the test. As if these things were not enough, once the air was injected every attempt was made to get it to flow into just about every nook and cranny within the skull. To accomplish this, the patient was placed on sort of tilt-a-whirl chair that spun them every which way—including upside-down. Imagine having the worst headache of your life, being utterly nauseous, probably vomiting, and then being flipped upside-down—repeatedly. Think about that next time you’re having a bad day.

For about 50 years or so, this, cerebral angiography, and plain xray were the only games in town. Today, pneumoencephalography is relegated to the pages of history. There is no real indication for it in this modern era of CT and MRI.

ICA-Angiogram

A cerebral angiogram. The black squiggles are the arteries of the brain, viewed as if looking at the side of the head. The carotid artery is the largest squiggle, coming up from the bottom of the image and branching like a tree.

Cerebral angiography was invented a few years after Dandy’s development of pneumoencephalography, in 1927, by a physician named Egas Moniz. Moniz was looking for a way to visualize the vessels inside the head. He finally settled on a solution containing heavy metals which are dense and easily visible on x-ray (though toxic to the kidneys in large doses). When injected into the arteries of the head and x-rayed, the arteries (and the veins as well) of the brain—the cerebral vasculature—are completely visualized.

This turns out to be useful both directly and indirectly. Directly because one can visualize aneurysms and other vascular malformations of great importance. Indirectly, and here we go back to the shadows again, because of what we can’t see. One of the most important past uses of cerebral angiography, as it is called, was to identify the presence or absence of epidural and subdural hematomas following trauma. This was done by reading the shadows, that is, the shift in the normal position of the blood vessels. If an acute epidural or subdural hematoma was present, it would push the normal vessels away from the side with the hemorrhage. That is, the presence of the hemorrhage would be implied by the lack of any vessels where they should normally exist.

The scenario went something like this: Little Joey gets hit by a car and is rushed to the ER. Finding him to be unconscious, but lacking any other clinical localizing signs to discern whether or not a blood clot was pushing on the brain (after all, he could just have a concussion, or worse, diffuse brain injury which does not respond to or require brain surgery), Little Joey would be rushed over to the radiology room where a neurosurgeon (not a radiologist in those days) would inject the solution of heavy metals directly into Little Joey’s carotid artery in the neck. A few quick x-rays of Little Joey’s head would be taken, and voila, the shadows would show the presence or absence of hematoma.

Or something like that.

SDHacuteShift

An acute subdural hematoma. The hemorrhage is the irregular white pattern on the right side of the image (which, do to the arbitrarily agreed upon conventions of imaging is the LEFT side of the patient’s head). A hemorrhage such as this pushes everything out of its normal place, including the vessels seen on an angiogram.

If Little Joey also had other injuries, he might just as well be whisked off to surgery for an operation on his belly or chest or whatever. Then the neurosurgeon would be left to his own devices in the operating room without any imaging to guide him. This often meant drilling a series of holes at strategic points around the head, sort of like drilling for oil. Problem was, you always got oil. The trick was to determine when you had a normal amount of oil or too much. And of course this was on top of the confusion of whatever other surgery was being conducted on Little Joey as well…

Thank God those days are largely behind us.

Oh, and that Moniz fella? In 1949 he won the Nobel Prize in Medicine for the development of his other great (uh, not so great?) contribution to medicine, the prefrontal lobotomy. Today, of course, lobotomies are rarely—if ever—indicated. But for a brief period in the late 1940s and 1950s, in the era before psychoactive medications, they were all the rage for treating psychiatric disorders. Of course, lobotomy does not treat psychiatric disease, it simply disconnects the emotional, thinking part of the brain—the part that contains little things like personality & makes you you—from everything else. Jack Nicholson’s character Randle Patrick McMurphy in Ken Kesey’s One Flew Over The Cuckoo’s Nest was lobotomized at the end of that great movie, and for once Hollywood got it right. The horrifically vacant, the lights are on but nobody’s home expression on Nicholson’s face when McMurphy returns from surgery was not an exaggeration. Not one of the Nobel committee’s more stellar moments.

As big a bust as lobotomy has proven to be however, cerebral angiography—which lead to the use of angiography throughout the body—has proven to be one of the greatest developments of modern medicine. None of the endovascular interventions for brain aneurysms, aortic aneurysms, heart disease, etc., would be possible without Moniz’s invention. In fact, it is no exaggeration to say much of modern medicine would not be possible without angiography. It saves hundreds of thousands of lives every year. That probably was Nobel worthy.

Edison McDaniels, MD, is a board certified neurosurgeon practicing in the American South. Follow him on twitter @surgeonwriter and read his fiction on Amazon in both paperback and kindle. 

Click here for the final installment. Next time: MRI & CT take over.

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