Case Studies in Physiology: Temporal variations of the lung parenchyma and vasculature in asymptomatic COVID-19 pneumonia: a multispectral CT assessment

• Published in: Journal of applied physiology (1985) Vol. 131; no. 2; pp. 454 - 463
• Main Authors: Nagpal, Prashant, Motahari, Amin, Gerard, Sarah E, Guo, Junfeng, Reinhardt, Joseph M, Comellas, Alejandro P, Hoffman, Eric A, Kaczka, David W
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.08.2021
• Subjects: Abnormalities; Asymptomatic; Blood volume; Case Studies in Physiology; Computed tomography; Coronaviruses; COVID-19; COVID-19 Testing; Diagnosis; Heterogeneity; Humans; Image registration; Infections; Lung - diagnostic imaging; Lungs; Male; Males; Mechanics; Mechanics (physics); Microvasculature; Parenchyma; Pathophysiology; Pneumonia; Pulmonary functions; Respiration; Respiratory function; Retrospective Studies; SARS-CoV-2; Temporal variations; Texture; Tomography, X-Ray Computed; Viral diseases; COVID-19; longitudinal analysis; lung parenchyma; dual-energy computed tomography; pulmonary vasculature
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00147.2021

This study reports systematic longitudinal pathophysiology of lung parenchymal and vascular effects of asymptomatic COVID-19 pneumonia in a young, healthy never-smoking male. Inspiratory and expiratory noncontrast along with contrast dual-energy computed tomography (DECT) scans of the chest were performed at baseline on the day of acute COVID-19 diagnosis ( ), and across a 90-day period. Despite normal vital signs and pulmonary function tests on the day of diagnosis, the CT scans and corresponding quantification metrics detected abnormalities in parenchymal expansion based on image registration, ground-glass (GGO) texture (inflammation) as well as DECT-derived pulmonary blood volume (PBV). Follow-up scans on showed improvement in the lung parenchymal mechanics as well as reduced GGO and improved PBV distribution. Improvements in lung PBV continued until . However, the heterogeneity of parenchymal mechanics and texture-derived GGO increased on and . We highlight that even asymptomatic COVID-19 infection with unremarkable vital signs and pulmonary function tests can have measurable effects on lung parenchymal mechanics and vascular pathophysiology, which may follow apparently different clinical courses. For this asymptomatic subject, post COVID-19 regional mechanics demonstrated persistent increased heterogeneity concomitant with return of elevated GGOs, despite early improvements in vascular derangement. We characterized the temporal changes of lung parenchyma and microvascular pathophysiology from COVID-19 infection in an asymptomatic young, healthy nonsmoking male using dual-energy CT. Lung parenchymal mechanics and microvascular disease followed different clinical courses. Heterogeneous perfused blood volume became more uniform on follow-up visits up to 90 days. However, post COVID-19 mechanical heterogeneity of the lung parenchyma increased after apparent improvements in vascular abnormalities, even with normal spirometric indices.