Last week, researchers from Turkey published an article in Radiology that outlined brain abnormalities detected on MRI scans of patients, positive for COVID-19, who are also in the intensive care unit (ICU). While those results garnered significant attention throughout the industry, the findings also prompted speculation from many in the specialty about the strength of the study and what information it actually provided about the neurological impact of COVID-19.
To gain some perspective on how radiologists – and other healthcare providers – should view the study results, Diagnostic Imaging spoke with Christopher Hess, M.D., Ph.D., distinguished professor and chair of radiology and biomedical imaging at the University of California-San Francisco. He offered insights on what the findings of the investigation mean and the potential value they provide.
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Diagnostic Imaging: What are your thoughts on this research?
Hess: There has been a lot of interest in whether and how COVID-19 affects the central nervous system, and there have been different ways of going about that – studying clinical neurological symptoms, studying cerebrospinal fluid (CSF), and studying imaging. There have been a lot of studies that are mostly case reports or single isolated events that describe what findings might be present in COVID-19. But, the reality is that, without a systematic study, it is difficult to understand what actually is caused by COVID-19 and what is an epiphenomenon of COVID-19 just from being sick and being in the intensive care unit (ICU) and having a severe illness.
Diagnostic Imaging: Given that, then, what does this study actually tell us that could be potentially actionable?
Hess: This study was unique in the sense that it was a relatively large cohort. They took 749 patients, and apparently 200 of them – about 30 percent – ended up in the ICU. About 50 of those – around 20 percent – had neurological symptoms, and 27 of that group went for an MRI. So, the size of the group is good. But, anytime you have a design like that where you’re not enrolling everyone for an MRI, you’re not studying everyone. You have to be aware of bias in selection to make sure what you’re seeing on the MRI reflects the greater group, not just the selected small group.
We know through all the various existing studies that there is a neurological impact of disease. We don’t know the precise anatomy or physiology of that at all. This study showed several imaging findings, but it didn’t really answer the question of why these findings occur. In particular, the number of patients who had CSF – which is really critical to the evaluation of a lumbar puncture is really critical to the evaluation of infectious illness. And, that number was very small, and there was no infection in the CSF. So, again, we’re stuck with the question of whether this is an epiphenomenon of people being sick or is it directly related to COVID-19? We didn’t really answer that because we were not able to directly show COVID in the CSF of any of the patients.