COVID-19 progression in hospitalized patients using follow-up in vivo CT and ex vivo microCT.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease-19 (COVID-19) which can lead to acute respiratory distress syndrome (ARDS) and evolve to pulmonary fibrosis. Computed tomography (CT) is used to study disease progression and describe radiological patterns in COVID-19 patients. This study aimed to assess disease progression regarding lung volume and density over time on follow-up in vivo chest CT and give a unique look at parenchymal and morphological airway changes in "end-stage" COVID-19 lungs using ex vivo microCT.
Methods: Volumes and densities of the lung/lobes of three COVID-19 patients were assessed using follow-up in vivo CT and ex vivo whole lung microCT scans. Airways were quantified by airway segmentations on whole lung microCT and small-partition microCT. As controls, three discarded healthy donor lungs were used. Histology was performed in differently affected regions in the COVID-19 lungs.
Results: In vivo , COVID-19 lung volumes decreased while density increased over time, mainly in lower lobes as previously shown. Ex vivo COVID-19 lung volumes decreased by 60% and all lobes were smaller compared to controls. Airways were more visible on ex vivo microCT in COVID-19, probably due to fibrosis and increased airway diameter. In addition, small-partition microCT showed more deformation of (small) airway morphology and fibrotic organization in severely affected regions with heterogeneous distributions within the same lung which was confirmed by histology.
Conclusions: COVID-19-ARDS and subsequent pulmonary fibrosis alters lung architecture and airway morphology which is described using in vivo CT, ex vivo microCT, and histology.
Competing Interests: Conflicts of Interest: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-22-1488/coif). BMV, GGR, WAW, and WJ report funding from KU Leuven (No. C16/19/005). WAW reports funding from Roche, Boehringer Ingelheim, and Galapagos. GMV and DEVR report funding from the Broere Charitable Foundation. LJC reports funding from Medtronic. RV reports funding from UZ Leuven (No. STG15/023). RV, VG, JK, A Vanstapel, TG, MV, and IG report funding from the Research Foundation-Flanders (FWO) (No. 12G8715N to RV, No. 11L9822N to VG, No. 1198920N to JK, No. 1102020N to A Vanstapel, No. 1S73921N to TG, No. 1SE4322N to MV, and No. 11N3922N to IG). MNB reports funding from the Ghent University Special Research Fund for the UGCT Centre of Expertise BOF.EXP.2017.0007. The other authors have no conflicts of interest to declare.
(2023 Journal of Thoracic Disease. All rights reserved.)