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.

Postmortem CT pulmonary findings in SARS-CoV-2-positive cases: correlation with lung histopathological findings and autopsy results

“…7 and 8). Lung PMCT patterns 1 and 2 identified in our study population are concordant with the most common findings on PMCT reported in the literature as the expression of severe pulmonary COVID-19 [16][17][18][19][20][21][22][23][24], though a higher prevalence of massive consolidation and GGOs of both lungs (pattern 1) was here detected [21,23,24]. The same pattern 1, attributed to advanced COVID-19 pneumonitis in the clinical setting [8][9][10][11][12][13][14][15], can be interpreted as a common final common pathway in respiratory illness related to severe lung involvement by the pathogen, resembling adult respiratory distress syndrome (ARDS).…”

“…This slight difference might be explained by the different study populations, reflecting different stages of COVID-19 affecting the lungs, with diffuse consolidations in both lungs being similar to ARDS considered in the clinical and postmortem literature as the expression of more advanced stages of lung pathology due to SARS-CoV-2 infection [14,21,23,24]. Pattern 2 of this study (represented by bilateral and multifocal consolidations and GGO with a "crazy-paving pattern"), similar to other PMCT studies, is the most typical imaging alteration of patients who died by the second week after symptom onset [31].…”

“…Complete consolidation of both lungs (indicative of ARDS) has also been reported in severe and advanced pulmonary COVID-19 [14]. In addition to the clinical literature, some postmortem CT (PMCT) imaging findings have been reported, though they are not specific or highly suggestive of lung SARS-CoV-2 infection [16][17][18][19][20][21][22][23][24]. As a consequence, PMCT imaging has been proposed as a useful tool for postmortem investigations in diagnosed or suspected cases of SARS-CoV-2 infection to augment the numbers of postmortem examinations, especially in the first wave [25] or more recently as a screening method for SARS-CoV-2 infection before autopsy [16][17][18][19][20][21][22]24].…”

“…In addition to the clinical literature, some postmortem CT (PMCT) imaging findings have been reported, though they are not specific or highly suggestive of lung SARS-CoV-2 infection [16][17][18][19][20][21][22][23][24]. As a consequence, PMCT imaging has been proposed as a useful tool for postmortem investigations in diagnosed or suspected cases of SARS-CoV-2 infection to augment the numbers of postmortem examinations, especially in the first wave [25] or more recently as a screening method for SARS-CoV-2 infection before autopsy [16][17][18][19][20][21][22]24]. In fact, due to the importance of preautopsy assessment of biological risk and the complexity of properly examining COVID-19 multiorgan involvement through sole autopsy, PMCT has been widely adopted in forensic investigations of SARS-CoV-2 suspected or ascertained-related deaths [16][17][18][19][20][21][22][23][24], especially during the first phase of the pandemic.…”

“…As a consequence, PMCT imaging has been proposed as a useful tool for postmortem investigations in diagnosed or suspected cases of SARS-CoV-2 infection to augment the numbers of postmortem examinations, especially in the first wave [25] or more recently as a screening method for SARS-CoV-2 infection before autopsy [16][17][18][19][20][21][22]24]. In fact, due to the importance of preautopsy assessment of biological risk and the complexity of properly examining COVID-19 multiorgan involvement through sole autopsy, PMCT has been widely adopted in forensic investigations of SARS-CoV-2 suspected or ascertained-related deaths [16][17][18][19][20][21][22][23][24], especially during the first phase of the pandemic. Nevertheless, both to validate PMCT in COVID-19 cases and ensure its diagnostic value-particularly when an autopsy is not performed-it is important to find evidence regarding concordance between data obtained through PMCT and through traditional forensic autopsy.…”