Abstract:

Coronavirus disease 2019 (COVID-19) has reached a pandemic stage in March 2020 and currently more than 220 million patients worldwide are infected. The characteristic findings of COVID-19 pneumonia are bilateral, peripheral, rounded ground-glass opacities (GGO) which are dominantly located in the lower lobes and that may be accompanied by consolidation. The distribution of the parenchymal lesions was reported to be bilateral (88%), multi-lobar (78%) and peripheral (76%), with a tendency to involve the posterior regions of the lungs (80%). Several other chest CT findings, such as interlobular septal thickening, bronchiectasis, “crazy paving” and halo sign, have also been reported but with a lower frequency. RSNA has published consensus statements to reduce report variability among radiologists and defined 4 main categories: typical, indeterminate, atypical, and negative, to provide a relative likelihood that these findings are attributable to COVID-19 pneumonia. It is vital to understand that imaging may be normal in the early stages of COVID-19, and many conditions may present with imaging findings mimicking COVID-19 pneumonia. Chest CT may be also used as a useful tool for better identification of patients who will benefit from more aggressive therapy. In addition, CT may be used to evaluate patency of pulmonary and coronary vascular structures and myocardial damage. Although CT scan is not recommended as a diagnostic and screening tool, it can be helpful to clinician for a fast and accurate decision-making and has a crucial role in the diagnosis, risk stratifying, and follow-up of the progression of COVID-19 pneumonia.

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