COVID‐19: Histopathological correlates of imaging patterns on chest computed tomography

Abstract

Background and objective Patients with coronavirus disease 2019 (COVID‐19) pneumonia present with typical findings on chest computed tomography (CT), but the underlying histopathological patterns are unknown. Through direct regional correlation of imaging findings to histopathological patterns, this study aimed to explain typical COVID‐19 CT patterns at tissue level. Methods Eight autopsy cases were prospectively selected of patients with PCR‐proven COVID‐19 pneumonia with varying clinical manifestations and causes of death. All had been subjected to chest CT imaging 24–72 h prior to death. Twenty‐seven lung areas with typical COVID‐19 patterns and two radiologically unaffected pulmonary areas were correlated to histopathological findings in the same lung regions. Results Two dominant radiological patterns were observed: ground‐glass opacity (GGO) (n = 11) and consolidation (n = 16). In seven of 11 sampled areas of GGO, diffuse alveolar damage (DAD) was observed. In four areas of GGO, the histological pattern was vascular damage and thrombosis, with (n = 2) or without DAD (n = 2). DAD was also observed in five of 16 samples derived from areas of radiological consolidation. Seven areas of consolidation were based on a combination of DAD, vascular damage and thrombosis. In four areas of consolidation, bronchopneumonia was found. Unexpectedly, in samples from radiologically unaffected lung parenchyma, evidence was found of vascular damage and thrombosis. Conclusion In COVID‐19, radiological findings of GGO and consolidation are mostly explained by DAD or a combination of DAD and vascular damage plus thrombosis. However, the different typical CT patterns in COVID‐19 are not related to specific histopathological patterns. Microvascular damage and thrombosis are even encountered in the radiologically normal lung.

Serum LDH: a potential surrogate to chest radiograph in pediatric Covid-19 patients to reduce radiation exposure

“…Most of these observations may be non-specific, and chest radiographs cannot distinguish COVID-19 from any other pediatric lung infection [ 24 ]. The biochemical changes precede the imaging changes in the chest in the COVID-19 infection [ 25 ]. The radiological changes in chest imaging in patients infected with COVID-19 are based on the underlying diffuse alveolar damage (DAD) pathology, and vascular damage and thrombosis are prevalent in the COVID-19-infected lung[ 25 ].…”

“…The biochemical changes precede the imaging changes in the chest in the COVID-19 infection [ 25 ]. The radiological changes in chest imaging in patients infected with COVID-19 are based on the underlying diffuse alveolar damage (DAD) pathology, and vascular damage and thrombosis are prevalent in the COVID-19-infected lung[ 25 ]. In an autopsy series, the researchers confirmed that significant pulmonary vascular damage occurred in radiographically normal lung areas and histologically normal pulmonary parenchyma [ 25 ].…”

Emerging and Established Histological Techniques for the Analysis of Thrombosis in COVID-19 Lungs

“…More recently, Qin et al used H&E staining and immunofluorescence to show histological evidence of endothelial dysfunction (in the form of VCAM1 staining) in an autopsied lung collected from a severe COVID-19 patient, as well as extensive edema, and evidence of viral staining ( 47 ). In H&E-stained lung sections from autopsy cases from COVID-19 patients, Kianzad et al also found histological evidence of edema, neutrophil infiltration, and diffuse alveolar damage ( 32 ). Similarly, Romanova et al ( 33 ), Bryce et al ( 34 ), Bidari Zerehpoosh et al ( 35 ), Mauad et al ( 36 ), Bruce-Brand ( 37 ), and Elsoukkary et al ( 38 ) used H&E staining to demonstrate diffuse alveolar damage and leukocyte infiltration in COVID-19 autopsy samples.…”

“…In a post-mortem examination study of 7 COVID-19 patients, Rapkiewicz et al employed H&E staining, immunostaining, and electron microscopy to demonstrate evidence of platelet-rich thrombi in the pulmonary microvasculature and thrombus formation in large pulmonary arteries ( 31 ). By studying H&E-stained lung sections from 8 autopsy cases from patients with COVID-19, Kianzad et al also found histological evidence of pulmonary thrombosis ( 32 ). Similarly, Romanova et al ( 33 ), Bryce et al ( 34 ), Bidari Zerehpoosh et al ( 35 ), Mauad et al ( 36 ), Bruce-Brand ( 37 ), Elsoukkary et al ( 38 ), and Grosse et al ( 39 ) used H&E staining to show evidence of lung thrombosis in COVID-19 autopsy samples.…”

“…In a postmortem examination study of 7 COVID-19 patients, Rapkiewicz et al employed H&E staining, immunostaining, and electron microscopy to demonstrate evidence of platelet-rich thrombi in the pulmonary microvasculature and thrombus formation in large pulmonary arteries (31). By studying H&E-stained lung sections from 8 autopsy cases from patients with COVID-19, Kianzad et al also found histological evidence of pulmonary thrombosis (32)…”