We do know that radiation can potentially increase your risk of harm of future malignancy, and in the growing brain, potentially even have effects on IQ. The good news is that in Canada, as compared to our neighbours to the south, because of the type of medicine that's practised and less risk of litigation and less defensive medicine, we are doing very well with reducing the number of unnecessary CT scans.
There are studies which have shown that the number of CTs that have been done has significantly decreased up to the point that, for our study, the rate was only approximately 1%, which is a very, very low rate of CT scans. Some of them are certainly indicated. With regard to CT imaging, which has the worrisome radiation, that is one thing on which we can say we've made great progress. That is one thing we address in our comprehensive concussion guidelines. We include recommendations on when a CT scan should be done, or not.
MRI is a different type of picture that does not use radiation. An MRI is done by magnets, with no risk of those X-ray or radiation effects. Unfortunately, MRIs do not show routine changes with concussion. One caveat is that there are now some experimental protocols. I'm involved in some research that is undertaking some of those studies as well, so full disclosure. There are some advanced MRIs that are looking at the way—without getting too technical—water moves through the brain, etc. Terms like ASL, DTI and the whole alphabet soup are ways to see if there are ways to better see how the brain changes with concussion.
What we're doing is also comparing to kids who either are normal or have had other types of injuries, like ankle injuries or others. There may be some promising ways to do that, using those advanced techniques, but they're experimental. If you were to go to your community hospital tomorrow and say, “I want that scan”, first, they wouldn't have written the code to program the computer to do it, and second, there wouldn't be a radiologist who has the expertise on how to interpret it because it's not a clinical test yet. It would be a neuroscientist who has studied those and who would do those.
My hope is that in time we may have some opportunities to use imaging, either through advanced MRI or other even more novel things, for example, fNIRS, which is functional near-infrared spectroscopy, which is just little probes looking at infrared light, without even having to be in a scanner. Are there other things we can use to better detect the brain changes that we can't see or test on our physical exam?