Typical and atypical COVID-19 computed tomography findings

Figure 4 Computed tomography Images of halo sign-reversed halo sign. A and B: 50-year woman admitted to the emergency room presenting fever and cough. Chest computed tomography showed nodular consolidations surrounded by a zone of ground glass attenuation in both lower lobes indicating the halo sign (orange arrows); and C: 36-year man admitted to the emergency room presenting fever and dyspnea. Chest computed tomography showed a focal rounded ground glass opacity surrounded by an incomplete ring-like consolidation indicating the reverse halo sign (blue arrow).