Frequency of atypical pulmonary manifestations of COVID-19 patients on chest CT-scan: a cross-sectional study

Background Chest CT is a crucial diagnostic tool in COVID-19 due to its high sensitivity. Typical chest CT findings such as reversed halo sign, vascular enlargement, and air-bronchogram are commonly recognized in the pandemic, but finding atypical signs is essential to diagnose. We aimed to investigate the prevalence of the atypical manifestations during the two months of 2022 and compare the results to studies conducted before its outbreak.Methods Those patients with positive, positive RT-PCR tests were reevaluated to see if they met the inclusion and exclusion. Demographic information of patients, including age and sex, was recorded. The computed tomography (CT) examination was carried out using a 100-slice scanner (Philips Brilliance 6 CT Scanner). Two radiology specialists evaluated SARS-CoV-2 RT-PCR-positive patients for atypical pulmonary CT findings separately. The obtained data were evaluated using R software version 4.1.1.Results 606 confirmed COVID-19 cases were included in this study based on inclusion and exclusion criteria during January and February 2022. 55% of patients were female, and the median age was 56 (IQR: 42, 69). More than half of the patients (59%) had atypical findings on their pulmonary CT examination. These findings showed that pleural abnormalities were the most frequent atypical finding. Among pleural abnormalities, pleural thickening was the most common (17%). The double halo sign represented the least frequent atypical sign (0.2%).Conclusions Atypical findings were more prevalent in this study than its predecessors, while we acknowledge that other factors, such as study design and patient population, could have impacted it. The presence of atypical signs generally was not correlated with specific demographic groups, while some of these signs were more frequent in particular groups.