Typical, rare and atypical CT findings in COVID-19 pneumonia: A pictorial review

Objectives: The objective of this pictorial review is to make radiologists and clinicians familiar with the typical, atypical and rare CT findings of COVID-19 pneumonia to help in diagnosis as well as in monitoring disease. Main text: Bilateral ground-glass opacities, whether isolated or coexisting with consolidations, and typically in basal, posterior and peripheral lungs are the key findings in COVID-19 pneumonia. With further analysis other typical, atypical and rare CT findings are described and we need to keep in mind that the radiological presentation is dynamic with a rapid evolutive phase, peaking at 10-11 days, and a subsequent absorption phase after 14 days with a decrease in opacities and increase in repairing signs. Conclusion: The presence of typical findings of COVID-19 pneumonia on a chest CT scan during the pandemic outbreak of SARSCoV-2 helps in diagnostic analysis. Chest CT scan has a reported sensitivity of 97-98% in times with a high pre-test probability. Some CT findings (crazy paving pattern and pleural effusion) as well as an increasing percentage of lung opacities are associated with a worse patient outcome, emphasizing the role of chest CT in determining the risk of disease progression. Furthermore chest CT scan is also useful in monitoring disease control. With these acknowledgement we want to give a useful overview of the chest CT manifestations in COVID-19 pneumonia to help decision making in daily practice.