Imaging Features and Dynamic Changes of Chest Computed Tomography in Patients Infected with SARS-CoV-2 Omicron Variants

Objective: To investigate the chest computed tomography (CT) findings and dynamic changes in patients infected with SARS-CoV-2 Omicron variants. Methods: 200 patients infected with SARS-CoV-2 Omicron variants were collected in Beijing Ditan Hospital, Capital Medical University from November 2022 to January 2023. These patients were divided into mild group, moderate group and severe/critical group according to the clinical classification. All patients’ clinical, laboratory and chest CT data were retrospectively analyzed. Results: Among 200 cases infected with SARS-CoV-2 omicron variant, the main clinical manifestations were fever, cough, sore throat and fatigue. There was a statistically significant difference in white blood cell count between the mild group and the medium group, and between the mild group and the severe/critical group. There were significant differences in erythrocyte sedimentation rate between mild and moderate groups, and between mild and severe/critical groups. Most of the lesions in mild group were subpleural (53.6%), while most of the lesions in moderate group (77.9%) and severe/critical group (88.9%) were mixed. The crazy-paving sign was statistically significant between the mild and severe/critical groups, and between the mild and moderate groups. There were significant differences in air bronchogram sign between the mild and the severe/critical groups, the mild and severe/critical groups , and the mild and moderate groups. The frequency of Ground Glass Opacity (GGO) was the highest at different intervals between the onset and the first chest CT. The proportion of GGO with consolidation/consolidation and air bronchogram sign gradually increased when the interval was more than 4 days. The proportion of GGO with consolidation/consolidation and air bronchogram sign gradually increased when the interval was more than 4 days. The highest proportion (95.4%) of crazy-paving sign appeared within the interval of 5-9 days, after which the proportion decreased. The frequency of irregular linear opacities, the proportion of pleural thickening and pleural effusion increased in patients with an interval more than 14 days. The median times to occurrence of GGO, GGO with crazy-paving sign, GGO with consolidation or consolidation and irregular linear opacities respectively were 4 days (2 days, 7 days), 9 days (7 days, 11 days), 13 days (10 days, 16 days) and 16 days (13 days, 19 days). Conclusions: Chest CT can reflect the distribution, morphology, dynamic imaging development and outcome of lesions in patients infected with SARS-CoV-2 Omicron variant, which is helpful for clinical treatment decision-making and efficacy evaluation.