Monday, January 22, 2007

Milestones in medicine: you make the call

For the start of the new year, the British Medical Journal decided to conduct a poll on the most important milestones in the history of medicine. Creating a short list of fifteen from which to choose, BMJ then opened the voting on its web site. Well, the results are in, and readers narrowly voted "sanitation" as the most important advance since 1840 (the year BMJ was established). It edged out antibiotics, which came in second, and anesthesia, which came in with the bronze. Medical imaging only received 4.2 percent of the vote, but if these voters had been at the history of medicine lecture on Friday, they might have thought twice before casting their ballots...

On Friday, Dr. C. Conrad Carter, professor of neurology here at OHSU, delivered a talk to the second-year medical students on the history of neuroradiology. Showing side-by-side comparisons of old-style x-rays versus modern MRIs, Carter illustrated the immense improvements in brain imaging that have developed just in the last sixty years. Back in the day, neurologists would remove cerebrospinal fluid from the brain (Carter assured the audience that, in fact, you could drain every last drop of CSF from the brain without killing the patient, who would nevertheless wind up with a really bad headache), and inject air into the subarachnoid spaces to provide contrast (cerebral ventriculography or pneumoencephalography). This was frequently done without any anesthesia--number three on the BMJ list--so there was no reprieve from that headache, either.

Back in the 1920s, a professor here at the University of Oregon Medical School wrote a paper on the use of methylene blue as a contrast medium; the idea was to inject it into one part of the spinal cord and then tap further down, to check for blockages. Various radioactive substances were later used with a fluoroscope, but these were often irritating to the meninges and would need to be "sucked back out" after the imaging was completed (and Carter's answer to a student's question on how this was done ended with, "Crude, I know." I'll spare you the details.)

Needless to say, these procedures are becoming lost arts. Good riddance, we may say, although we're also losing the art of physical examination apart from high-tech imaging. Carter cautioned the young medics: imaging technology is proceeding so fast that we're not even sure what we're looking at in those images, all those crannies and areas--what are the normal sizes for certain areas, for patients of a certain age? What is indicative of natural variation, and what of disease? The most important corollary to modern neuroimaging is extensive study of neuroanatomy. And did you know that many of our early anatomists here at UOMS were, in fact, neuroanatomists? But that's a topic for another day...

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