Neuroimaging findings of COVID-19: a systematic review on longitudinal studies

Background: There is high number of evidence regarding the involvement of the central nervous system (CNS) in patients with severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). The aim of our systematic review study is to evaluate the current state of knowledge regarding neuroimaging findings after COVID-19 by focusing on longitudinal studies. By limiting our review to this type of study design, we aimed to provide a more comprehensive and detailed picture of the long-term effects of COVID-19 on the brain.Methods: Three electronic databases (PubMed, Scopus, and Web of Science) were searched for relevant studies. We included studies that investigated longitudinal brain changes in patients with COVID-19 with available neuroimaging findings at least two different times.Results: After a two-step review, 10 studies were included in our qualitative synthesis. Brain MRI was the only imaging modality in seven studies, whereas one used only FDG-PET, one used CT/MRI, and one used CT/MRI/FDG-PET. Our results demonstrated consistent evidence of lesions, white matter microstructural, grey matter, metabolism, and blood flow alterations in comparison with healthy controls.Conclusion: Our systematic review provides evidence of widespread microstructural, grey matter, metabolism, and blood flow alterations in patients afflicted with COVID-19. The longitudinal nature of the included studies highlights the importance of ongoing monitoring and follow-up imaging in patients after COVID-19 infection.