Objective: To explore the evolution of imaging findings on dynamic chest high resolution CT (HRCT) in patients with mild COVID-19.
Methods: The data of epidemiology, clinical data and continuous dynamic chest high-resolution CT images of the patients with mild COVID-19 were analyzed retrospectively . Twenty-five patients (including 24 common type and 1 mild) were enrolled in the group, including 14 males and 11 females, with age of (42±12) years and hospital stay of (19±5) days . The basic images and dynamic images of HRCT were analyzed and compared by the radiologists .
Results: The clinical manifestations were fever (22 cases), cough (18 cases), expectoration (8 cases), pharyngeal pain (6 cases). Most laboratory tests lacked specificity . There were no significant abnormalities on chest CT of one mild patient . HRCT findings of the common type were as follows: (1) the distribution of the lesions: most of the multiple lesions involved both lungs (19 cases), with average of 3 (3±1) lobes, located in the peripheral pulmonary zone near the pleura (22 cases); (2) the morphology and density of the lesions: most of the lesions were ground glass density foci (22 cases), which were patchy and massive (18 cases), nodular (10 cases) and arc broadband (7 cases); with the development of the disease, the density of some lesions increased with localized pulmonary consolidation (10 cases), accompanied by air bronchus sign (5 cases) and halo sign (5 cases). Dynamic changes of HRCT images in the chest: the positive manifestations were found on the 5th (5 , 6) day after the onset of the disease, the progressive time of CT lesions was 5 (5 , 7) days, the peak time of CT lesions was 11 (10 , 13) days, and the turning time of CT lesions was 9 (8 , 11) days .
Conclusions: Dynamic chest HRCT can monitor the basic evolution process of the disease in patients with mild COVID-19, and provide a more intuitive basis for clinical early diagnosis and treatment.