Radiological Imaging of Viral Pneumonia Cases Identified Before the COVID-19 Pandemic Period and COVID-19 Pneumonia Cases Comparison of Characteristics (preprint)

ABSTRACT

Background: Thoracic CT imaging is widely used as a diagnostic method in the diagnosis of COVID-19 pneumonia. Radiological differential diagnosis and isolation of other viral agents causing pneumonia in patients gained importance, especially during the pandemic period. Aims: We aimed to investigate whether there is a difference between the CT imaging findings characteristically defined in COVID-19 pneumonia and the findings detected in pneumonia due to other viral agents, and which finding may be more effective in the diagnosis. Study Design: The study included 249 adult patients with pneumonia found in thorax CT examination and positive COVID-19 RT-PCR test and 94 patients diagnosed with non-COVID pneumonia (viral PCR positive, no bacterial/fungal agents were detected in other cultures) from the last 5 years before the pandemic. It was retrospectively analyzed using the PACS System. CT findings were evaluated by two radiologists with 5 and 20 years of experience who did not know to which group the patient belonged, and it was decided by consensus. Methods: Demographic data (age, gender, known chronic disease) and CT imaging findings (percentage of involvement, number of lesions, distribution preference, dominant pattern, ground-glass opacity distribution pattern, nodule, tree in bud sign, interstitial changes, crazy paving sign, reversed halo sign, vacuolar sign, halo sign, vascular enlargement, linear opacities, traction bronchiectasis, peribronchial wall thickness, air trapping, pleural retraction, pleural effusion, pericardial effusion, cavitation, mediastinal/hilar lymphadenopathy, dominant lesion size, consolidation, subpleural curvilinear opacities, air bronchogram, pleural thickening) of the patients were evaluated. CT findings were also evaluated with the RSNA consensus guideline and the CORADS scoring system. Data were divided into two main groups as non-COVID-19 and COVID-19 pneumonia and compared statistically with chi-square tests and multiple regression analysis of independent variables. Results: Two main groups; RSNA and CORADS classification, percentage of involvement, number of lesions, distribution preference, dominant pattern, nodule, tree in bud, interstitial changes, crazy paving, reverse halo vascular enlargement, peribronchial wall thickness, air trapping, pleural retraction, pleural/pericardial effusion, cavitation and mediastinal/hilar lymphadenopathy were compared, significant differences were found between the groups (p < 0.01). Multiple linear regression analysis of independent variables found a significant effect of reverse halo sign ({beta} = 0.097, p <0.05) and pleural effusion ({beta} = 10.631, p <0.05) on COVID-19 pneumonia. Conclusion: Presence of reverse halo and absence of pleural effusion was found to be efficient in the diagnosis of COVID-19 pneumonia.