Post-mortem CT lung findings at a medicolegal institute in SARS-CoV-2 RT-PCR positive cases with autopsy correlation

Abstract

CoVID-19 is a novel viral infection with now well-established clinical radiological findings. There is limited data on post-mortem imaging. We explore the proposition that PMCT could be used as screening test. In an 11-week period, 39 deceased persons were referred for medicolegal investigation with pre-existing or subsequent nasopharyngeal swabs showing positivity on SARS-CoV-2 RT-PCR testing. All 39 had routine whole-body CT scans on admission and 12 underwent medicolegal autopsy. These cases were contrasted with 4 others which were negative on nasopharyngeal swabs despite PMCT findings suggestive of CoVID-19 pneumonia (designated false positive). Nine of the 12 autopsies showed lung histology consistent with those reported in CoVID-19 pneumonia. Typical clinical CoVID-19 lung findings on PMCT were only detected in 5 (42%). In 3 of the 4 false positive cases, lung findings showed non-COVID-19 histology but in 1, findings were identical. PMCT CoVID-19 findings in the lungs are therefore not specific and may not be detected in all cases due to obscuration by expected agonal CT findings or other pathologies that pre-dated SARS-CoV-2 infection. PMCT findings may otherwise be subtle. Although PMCT may hint at CoVID-19, we believe that nasopharyngeal swabs are still required for definitive diagnosis. Even with positive swabs, clinical CoVID-19 lung findings on PMCT are often not detected. PMCT findings can be subtle, extreme or obscured by agonal changes. Given this range of PMCT changes, the challenge for pathologists is to determine whether death has been caused by, or merely associated with, SARS-CoV-2 infection.