CT halo sign. A 27-year-old female patient presented with cough, loin to groin pain, and fever. A CT of the abdomen was performed to look for renal calculi. However, in view of her cough, her chest was also scanned for evidence of COVID-19. An axial non-contrast chest CT image demonstrated an example of a halo sign. There was a discrete focal consolidation within the left lower lobe as outlined in the red box. The nodule showed a peripheral rim of ground-glass opacification, halo sign (black arrows)COVID-19: coronavirus disease 2019; CT: computed tomography