Table 1. Group Staging Based on Chest CT Findings From a Retrospective Study on 81 Patients.

Groups	Duration of symptoms	CT chest findings
Group 1	Subclinical	Unilateral ground-glass opacities
Group 2	Less than 1 week	Bilateral ground-glass opacities
Group 3	1 - 2 weeks	Decrease in ground-glass opacities
Group 4	2 - 3 weeks	Consolidation and mixed patterns

CT: computed tomography.