Chest CT images
Chest CT scan could offer reliable evidence for the detection of SARS-CoV-2 infection. Japanese scholar Inui et.al conduct a study on the chest CT of 112 cases from the cruise ship “Diamond Princess” with COVID-19[34]. They found 73% (82/112) were asymptomatic infections, 54% (44/82) of the asymptomatic cases had lung opacities on CT. They concluded that asymptomatic cases showed more GGO(ground-glass opacity)than consolidation and milder extension of lung parenchymal opacities. Another study is from the Central Hospital of Wuhan, China. Wang et al. make a retrospective analysis on the CT images from 159 asymptomatic cases with COVID-19 and found that the lesions in the lung were mostly peripheral distribution in 142 cases (89.3%) and bilateral distribution in 91 cases (57.2%), as well as more than two lung lobes were involved in 100 cases (62.9%). Most of the lesions were GGO (95%). In short-term follow-up, the majority of asymptomatic patients had a good prognosis (73.7 %) and none of them had extrapulmonary complications[35]. Hu et al. present the characteristics of chest CT images of 24 asymptomatic cases (but 5 cases developed symptoms later) and found that 8/19 cases showed ground-glass or patchy shadows, 4/19 cases showed stripe shadows which seems as an atypical image finding, and the rest 7/19 cases showed normal images[25].
These studies found that the chest CT images of asymptomatic cases were mainly GGO and most of them restored quickly, even though the sample size was small. However, the first two surveys did not indicate whether any of these asymptomatic cases developed symptoms later and what was the prognosis with different chest CT lesions. We expect more data on chest CT findings of the full-course asymptomatic carriers.