Objectives: To evaluate the frequency and time course of RHS on CT in patient with COVID-19 pneumonia. Materials: and methods A total of 147 patients with COVID-19 pneumonia were divided into mild, moderate, severe and critical categories. The number, location, shape, wall appearance of RHS on CT were analyzed. Other parenchymal abnormalities include GGO, consolidation and linear opacity were also recorded. Results: RHS was observed in 37 (25.2%) of 147 patients and it was more common in patients with moderate disease than severe or critical disease (31.3% vs. 13.0%, P = 0.019). Time from symptom onset to appearance of RHS was 9 ± 5 days in moderate patients and 14 ± 8 days in severe/critical patients. A total of 64 RHS lesions were identified and the majority of lesions were located in peripheral aspect of lungs (55, 85.9%) and lower lobes (52, 81.2%). All lesions with RHS were round or oval-shaped. The rim of RHS were smooth in 54 (84.4%) and irregular in 10 (15.6%). Follow-up CT scans of 27 patients (50 lesions) showed 43(86%) lesions gradually resolved or developed into GGO and linear opacities and 7(14%) lesions remained unchanged appearance. Conclusions: RHS occurred sooner after symptom onset and with higher frequency in patients with moderate compared to those with severe or critical disease. RHS may represent a favorable prognostic sign in COVID-19 pneumonia. Key Points • 37 (25.2%) of 147 patients with COVID-19 pneumonia had RHS on at least one CT• RHS was more prevalent in patients with moderate disease than those with severe or critical disease• RHSs (78.4%) mostly occurred within 2 weeks after symptom onset
The Reversed Halo Sign in COVID-19 Pneumonia