Spectrum of Vascular Involvement in Coronavirus Disease 2019 Pneumonia-Findings on CT Perfusion

There is accumulating evidence of a distinct coagulopathy in severe acute respiratory syndrome coronavirus 2 infection which is associated with poor prognosis in coronavirus disease 2019. Coagulation abnormalities in blood samples resemble systemic coagulopathies in other severe infections but demonstrate specific features such as a very high d-dimer. These clinical observations are consistent with histopathologic findings of locally disturbed pulmonary microvascular thrombosis and angiopathy in end-stage coronavirus disease 2019. However, exact underlying processes and the sequence of events are not fully understood. CT perfusion may provide insight in the dynamic aspect of the vascularity in pulmonary lesions in coronavirus disease 2019 infection as, in contrast to dual energy CT, a multiphase perfusion pattern is displayed. In six patients with coronavirus disease 2019 pneumonia, findings on additional CT perfusion series were correlated with known histopathologic vascular patterns upon pulmonary autopsy of patients who had died of coronavirus disease 2019. In this case series, we were able to show perfusion changes on CT scans in typical pulmonary lesions illustrating diverse patterns. We demonstrated hyperperfusion in areas with ground glass and a severely decreased perfusion pattern in more consolidated areas often seen later in the course of disease. A combination was also observed, illustrating temporal heterogeneity. These findings provide new insights into the pathophysiology of coronavirus disease 2019 pneumonia and further understanding of the mechanisms that lead to respiratory failure in these patients.