CT appearance of new coronavirus pneumonia in subclinical period and short-term changes

Objective To explore the characteristics and short-term changes of high resolutionCT (HRCT) in subclinical stage of new coronavirus pneumonia (NCP). Methods TheHRCT images of 17 NCP patients in subclinical stage were analyzed retrospectively in Union Hospital of Tongji Medical College, Huazhong University of science and technology and Wuhan JinyintanHospital from January 15 to January 31, 2020. There were 4 males and 13 females, aged from 25.0 to 51.0 (39.8±7.5) years, who were closely contacted with NCP patients. The follow-up CT examination was performed 3 to 6 days after the initial CT examination in all patients. Six patients were treated using anti-virus, anti-inflammation andsymptomatic therapy, while the orther 11 patients were untreated. The CT imaging signs of subclinical and short-term follow-up were analyzed, and the CT image changes of short-term follow-up was summarized. Results Thelesions of 17 NCP patients were mainly located at the lower lobes of both lungs (9 cases at the left lower lobe and 10 cases at the right lower lobe in the subclinical stage, 9 casesat the left lower lobe and 11casesat the right lower lobe in the short-term follow-up). The number of lung segments involved increased from 46 in the subclinical stage to 90 in the short-term follow-up. In the subclinical stage, most of the lesions were multiple (13 cases), while in the short-term follow-up, the number of multiple cases decreased (7 cases), focal (6 cases) and diffuse distribution(4 cases) increased. The lesions were mainly distributed under the pleura (13 cases) or along the bronchovascular bundle (10 cases). In the short-term follow-up, 1 case progressed from subpleural to subpleural and along the bronchovascular bundle. There were 3 main types of lesions, including ground glass nodule, ground glass opacity and crazy-paving pattern. In the subclinical stage and short-term follow-up, ground glass nodules were seen in all the 17 cases. In the short-termfollow-up, ground glass nodules decreased in 4 cases and crazy-paving pattern increased in 4 cases. In 6 patients after treatment, 3 cases were changed from multiple to single ground glass nodule, 3 cases showed multiple ground glass opacity reduced. Therange of lesions in 11 patients without treatment enlarged. Conclusion TheHRCT features of the NCP patients in subcilincal stagehave some charicteristics, such as small ground glass nodule, ground glass opacity along the subpleural or along the bronchovascular bundle, and the great changescan be seen in the short-term follow-up.