A 54-year-old woman who presented with fever. (a) Axial thin-section unenhanced CT images showed multifocal nodular opacities with peribronchial and subpleural distribution (arrows) in both lungs on day 2 of symptoms. (b) Follow-up CT on day 8 showed newly developed ground-glass opacities (arrowheads) and decreasing density of the nodular opacities, with reversed halo sign (arrows). (c) Last follow-up CT on day 11, 3 days after initiation of antiviral treatment, showed significantly improvement of the ground-glass opacities.