Radiological Characteristics of Patients Infected with Coronavirus Disease-2019 (COVID-19): A Retrospective, Observational Study from Iran

Background: Management of Covid-19 patients is key to control the pandemic. In this line, access to chest Computed Tomography (CT) scan findings and investigating changes during initial diagnosis until recovery is of crucial importance. Objectives: The present study aimed to investigate the chest CT-scan findings of patients with a definitive diagnosis of Covid-19 in Guilan, Iran. Methods: In this retrospective study, 1000 patients with a definitive diagnosis of Covid-19, from 20 April to 30 July 2020, were enrolled. Their first and follow-up chest CT-scans were obtained. Total lung involvement was determined by the number of lobes involved and by scoring 0 to 5 for each lobe (5 lobes, lowest score: 0, and highest score: 25). Results: In this study, three CT-scans of all 1000 patients were studied. Patients were classified into 4 stages according to their hospitalization duration (ranging from 0 to 30 days): stage 1 or primary (0 to 7 days): ground-glass opacities (n = 178 or 89%), stage 2 or progressive (8 to 15 days): increased crazy-paving pattern (n = 89 or 44.5%), stage 3 or peak involvement (16 to 22 days): consolidation (n = 78 or 89%), and stage 4 or decreased pulmonary involvement severity (greater than 23 Day): the gradual resolution of consolidation (n = 178 or 89%). Conclusions: Chest CT-scan findings revealed that patients with Covid-19 had a high rate of pulmonary involvement, on average, for the first 15 days, which then declined.