Response.

To the Editor:

We thank Rotzinger and Qanadli for the interest in our article on the chest CT imaging signature of coronavirus disease 2019 (COVID-19) infection. In our article, we reported a pooled prevalence of vascular thickening of 72.9% (95% CI, 64.4% to 81.4%) in patients with COVID-19. At the time our article was published, there was a lack of scientific data that correlated chest CT imaging to postmortem pathologic findings in this disease. Recently, Henkel et al published a series of 14 patients who died of COVID-19, in whom a morphologic comparison of antemortem chest CT scans with postmortem gross findings and histopathologic findings was performed. Five of 14 patients in their study also underwent contrast-enhanced CT imaging. Both vascular thickening (vascular enlargement/vascular congestion) and pulmonary arterial enlargement (related to the corresponding bronchus) were present in 12 of 14 patients (86%) on chest CT imaging. Based on their histopathologic correlation and previous autopsy studies, , Henkel et al speculated that the observation of enlarged pulmonary arteries might be related to an increase of parenchymal and predominantly intravascular pressure, due to severe COVID-19 pulmonary microangiopathy that affected the alveolar capillary network. The high incidence of microthrombosis was also thought to be suggestive of a possible underestimation of the vascular alterations associated with COVID-19 with the use of imaging, especially on unenhanced scans. Henkel et al concluded that both severe acute lung injury and vascular complications contribute to fatal outcomes. These considerations largely resonate with the excellent remarks by Rotzinger and Qanadli. Nevertheless, the scientific evidence on the pathophysiologic condition and clinical relevance of vascular changes on chest CT imaging in COVID-19, besides frank pulmonary embolism, is still limited, and the interpretation of this limited evidence remains somewhat speculative. Further studies are warranted to understand the nature of vascular abnormalities seen on chest CT scans and how this can help to improve patient management and outcome.