Among the epiphenomenon, there are several things that could be going on. We’ve all heard about the vascular risk or the vascular thrombotic risk factors that some have articulated. In this study, they did have two patients – one with large vessel stroke and one with dural sinus thrombosis. But, would these findings described in the article be related to some underlying vascular cause? Certainly, they could. Or, it could be due to some outcome related to the physiology of COVID rather than direct COVID. Among the possibilities, there’s direct neural tropism or direct brain invasion by the bug. That’s relatively unlikely. And, in this case, given the CSF, I still think it could be vascular.
And, remember, sick patients have all kinds of metabolic derangements. They often have seizures, and in critically ill patients with COVID-19, in particular, they certainly have respiratory issues. Relatively pure hypoxia could certainly change the physiology of the brain such that gives rise to some of these findings.
I think this study shows an association between the virus and these findings much in the way that prior clinical studies have shown some association of neurologic symptoms with COVID-19. This shows the association of some imaging findings with COVID. But, there’s no direct causal link. The authors made the statement that prior SARS viruses have been shown to have a neurotropism and have even demonstrated in the autopsy samples of some brains. But, that hasn’t been shown for COVID-19, so we just don’t know.
Diagnostic Imaging: Going forward for radiologists and the providers with whom they collaborate, what’s the value of this study’s findings?
Hess: It’s important to be able to recognize so we don’t make a fallacy of misattribution – of attributing the findings you see to some other disease process. Just knowing that this has been seen in patients with COVID before may provide some diagnostic certainty in terms of understanding what the cause of the imaging finding is. I think there is some scientific value here, as well, and understanding what types of neuro-imaging findings are present in patients with COVID.
I also think, secondarily, this shows the real value of multi-modal evaluation of neurologic disease. It has to be really combined with understanding of symptoms, imaging findings, and CSF together. The CSF especially is a critical piece that is lacking in most of the patients included in this study.
Diagnostic Imaging: Are these findings indicative of a need to scan more patients, particularly with MRI?
Hess: The reasons for scanning a patient are really driven by the clinical situation. A patient in the ICU with neurologic deficits – whether they have COVID-19 or not – should probably have an MRI to evaluate why they’re having neurologic deficits. Will it increase the number of scans or should it increase the number of scans that are being done in COVID patients? I don’t think so because there’s no direct treatment of any of the imaging findings that were shown here. There’s no indication for doing this on a routine screening basis to evaluate them.