Comparison of Chest CT Scan Findings of 20- to 50-Year-Old Patients With Mutated COVID-19 and Early COVID-19 (2019 and 2020) in the Southeast of Iran

Background Chest CT is a widely accessible imaging modality that facilitates timely evaluation in patients suspected of COVID-19. As SARS-CoV-2 mutated over time, identifying differences in radiologic presentation can aid clinical management. Methods In this retrospective study, we examined chest CT scans of 360 patients with confirmed COVID-19 via RT PCR, divided into 2 equal groups: 180 with mutated COVID-19 (predominantly Delta variant) and 180 with early (original) COVID-19. All participants were aged 20 to 50 years and had no underlying medical conditions. CT findings were analyzed for ground glass opacities (GGOs), consolidation, nodules, pleural/pericardial effusion, bronchial wall thickening, subpleural banding, number of lobes involved, and estimated lung conflict. Statistical analyses were conducted using SPSS v24. Results GGO was found in 77.2% of mutated COVID-19 patients and 83.3% of early COVID-19 patients ( P = 0.145). Consolidation and reverse halo sign were significantly more frequent in mutated cases (63.3% and 18.3%) than early COVID-19 (48.9%, 9.4%) ( P < 0.05). Conversely, nodules, halo sign, pleural and pericardial effusions, and subpleural banding were more prevalent in early COVID-19 ( P < 0.05). Average number of lobes involved and lung conflict percentage were higher in mutated cases (2.92 lobes, 58.8%) compared to early COVID-19 (2.63 lobes, 34.8%) ( P < 0.001). Conclusions Although GGO and bronchial thickening were common across both groups, mutated COVID-19 showed increased consolidation and lung conflict. Early COVID-19 showed higher rates of nodules, halo signs, and effusions. These findings reflect underlying variations in pathophysiologic response and viral evolution.