Radiological changes of serial CT examinations in patients recovering from coronavirus disease 2019 (COVID-19)

Abstract Purpose: To find the pulmonary CT imaging characteristics in patients recovering from coronavirus disease 2019 (COVID-19).Method: Twenty patients with confirmed COVID-19 were enrolled. We analyzed the changes of four pulmonary CT imaging manifestations (ground glass opacity, consolidation, crazy paving sign and cord/band sign) in patients during hospitalization. The disease course was divided into four stages: early stage (0-4 days), progressive stage (5-8 days), peak stage (9-13 days) and absorption stage (≥14 days).Results: There were 12 male and 8 female with an average age of 45±16 years. In the first three stages, GGO was the most common sign on CT imaging. Then, the proportion of GGO decreased in the absorption stage compared with the first three stages (P<0.05). The proportion of crazy paving sign peaked in the progressive stage and then declined, with statistical difference between the progressive stage and the absorption stage (P<0.05). Cord/band sign was increasing from the early stage to the absorption stage, and statistical differences were found between the early stage and the peak stage (P<0.05), as well as the absorption stage and the first three stages (P<0.05). No statistical differences of consolidation proportion were found among the four stages.Conclusions: CT imaging showed different characteristics during the four stages. The proportion of cord/band sign significantly increased in the third stage, which might be an indicator of COVID-19 improvement.