Dynamic evolution of lung abnormalities evaluated by quantitative CT techniques in patients with COVID-19 infection

Abstract

Chest CT evaluation is often vital to determine patients suspected of COVID 19 pneumonia The aim of this study was t o determine the evolution of lung abnormalities evaluated by quantitative CT techniques in patients with COVID 19 infection from initial diagnosis to recovery. This retrospective study included 16 patients with COVID 19 infection from 30 January 2020 through 11 March 2020. Re peat chest CT examinations were obtained for three or more scans per patient. We measured total volume and mean CT value of lung lesions in each patient per scan, and then calculated the mass, which equals to volume*(CT value +1000). Dynamic evolution of chest CT imaging as a function of time was fitted by nonlinear regression model in terms of mass, volume, and CT value, respectively. According to the fitting curves, we redefined evolution of lung abnormalities : progressive stage (0-5 days), infection emerged and rapidly aggravated; peak stage (5-15 days), the greatest severity at approximate 7 8 days after onset; and absorption stage (15-30 days), the lesions slowly and gradually resolved.