I’ve seen cross-sectional slices of brains confirmed to have CTE (Chronic Traumatic Encephalopathy) and these slices all seem to differ greatly from a normal looking brain. Currently, why can’t a CTE diagnosis be confirmed with medical imaging, but only through autopsy?
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It isn’t really an exciting answer… it’s down to the damage being too small to see in a head CT. The resolution of MRI’s and PETscans are too low and don’t show the damage. When you section the brain and examine it under a microscope, only then does the diffuse axonal injury become apparent.
Medical imaging is great for anything involving altered blood flow, change in the anatomy (tumors, bleeds, changes in overall shape and size), and altered metabolism, but CTE isn’t any of that.
CTE causes brain matter to atrophy, or shrink. A lot of other diseases, like Alzheimer’s, can cause brain matter to atrophy as well, so it’s hard to look at a brain scan and know exactly what the disease is. You can make an educated guess based on patient history (ex. participation in contact sports and a history of concussions makes CTE a likely cause of the damage), but for now, doctors cannot know for certain what disease is causing the atrophy until they can actually sample the diseased tissue.
Source: https://www.nhs.uk/conditions/chronic-traumatic-encephalopathy/
A number of diseases can only be diagnosed at autopsy because it is the only way to be *absolutely* sure. For example, creutzfeld-Jakob disease.
In the case of CJD, even though technically it cannot be diagnosed during life, normal testing such as MRI can make a diagnosis of “probable CJD” with be right nearly 99 times out of 100.
Its the same with CTE, the brain shrinking, bleeds and scarring are obvious, but there other some other things which can cause them, for example, multiple strokes, cerebral amyloid angiopathy, etc. So, the only way to be sure is to examine the brain tissue. However, like CJD, when you look at the whole picture in a severe case (too young for cerebral amylod angiopathy, multiple previous concussions, etc.) you can usually give a diagnosis of “probable CTE” when the disease is severe enough. For early/mild disease, the changes might be too slight and easily missed, so diagnosis at this stage is often not reliable.
Lots of things make your brain look weird at large scale, in largely similar ways. To determine which particular thing made any particular brain look weird, you need microscopic level detail, only available at autopsy.
Let’s ask Herschel Walker to do his patriotic duty and dedicate his live brain to fighting this disease.
My Mum died from CTE yesterday. This is the best guess the doctors have. After CT MRI a lumbar puncture and many blood tests. Still all they can say is, ‘this is our best guess’.
I’m not cross with them.
I found this post informative and strangely comforting.
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