Project Summary A growing body of evidence indicates that COVID-19 has neurological manifestations, many of which may persist post-infection. 36% to 67% of COVID-19 patients develop neurological symptoms, including anosmia, headache, and altered consciousness, and many present with severe acute neurological manifestations, including stroke. In one study, 44% of COVID-19 patients with neurological manifestations in an ICU who received an MRI had abnormal imaging findings. Given the number of individuals who have been infected with COVID-19 since early 2020, persistent neurological effects are a critical and growing public health problem. Linking the neurological effects of COVID-19 that persist in recovered patients to specific MRI-visible abnormalities remains a critical unmet need. This information will be extremely valuable in understanding how to best treat, predict, and ultimately prevent long-term neurological effects of COVID-19. 7 Tesla (7T) MRI enables us to produce images with exquisite resolution and contrast, and has revealed subtle structural and functional abnormalities in a range of neurological diseases and disorders, particularly when the abnormalities are below the threshold of detectability of conventional MRI. Highly sensitive, multi-modal neuroimaging techniques could provide new insight into the mechanisms by which SARS-CoV-2 indirectly or directly affects the brain, leading to more informed management of neurological manifestations of COVID-19 in both the acute and chronic phases. Our central hypothesis is that a retrospective analysis of COVID-19 cases with a brain MRI, followed by a prospective study using advanced 7T multimodal MRI of the brain and brainstem, will provide extensive and detailed insight into the neurological manifestations of COVID-19, allowing for improved mechanistic understanding of the chronic neurological effects of the disease and improved treatment of neurological sequelae. In this study, we will apply a 7T structural, vascular, functional, and diffusion MRI protocol to 55 patients who were previously hospitalized for COVID-19, experienced neurological symptoms during their hospitalization, and underwent clinical MRI at that time as a result of these symptoms. Scanning will be performed 6-months post-recovery. 55 age- and gender-matched healthy controls will be studied using an identical 7T protocol. The specific aims of our study are to (1) perform a retrospective analysis of 200 brain MRIs performed on COVID-19 patients with neurological symptoms and tabulate the frequencies of specific neuroimaging findings; (2) perform qualitative and quantitative analysis of 7T structural, vascular, and diffusion images in 55 recovered COVID-19 patients and compare MRI-based metrics to healthy controls; and (3) perform connectomic network analysis on functional and diffusion images to identify network differences in patients versus controls. We expect that frequencies of neurological abnormalities and quantita...