AUTHOR=Chen Qiuying , Chen Lv , Liu Shuyi , Chen Luyan , Li Minmin , Chen Zhuozhi , You Jingjing , Zhang Bin , Zhang Shuixing 

TITLE=Three-Dimensional CT for Quantification of Longitudinal Lung and Pneumonia Variations in COVID-19 Patients

JOURNAL=Frontiers in Medicine

VOLUME=Volume 8 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.643917

DOI=10.3389/fmed.2021.643917

ISSN=2296-858X

ABSTRACT=Objectives: Visual chest CT is subjective with large inter- and intra-observer variability. We aimed to quantify the dynamic changes of lung and pneumonia on three dimensional CT (3D-CT) images in coronavirus disease 2019 (COVID-19) patients during hospitalization.   
Methods: A total of 110 laboratory-confirmed COVID-19 patients who underwent chest CT from January 3 to February 29, 2020, were retrospectively reviewed. Pneumonia lesions were classified as four stages: early, progressive, peak, and absorption stages on chest CT. A computer-aided diagnostic (CAD) system calculated total lung volume (TLV), percentage of low attenuation areas (LAA%), volume of pneumonia, volume of ground-glass opacities (GGO), volume of consolidation plus GGO: consolidation ratio. CT score was visually assessed by radiologists. Comparisons of lung and pneumonia parameters among the four stages were performed by one-way ANONA with post hoc tests. The relationship between CT score and volume of pneumonia, and between LAA% and volume of pneumonia in four stages was assessed by Spearman’s rank correlation analysis.  
Results: The patients underwent a total of 534 chest CT scans with a median interval of 4 days (interquartile range, 3-5 days). TLV, LAA% and GGO: consolidation ratio were significantly decreased while volume of pneumonia, GGO, and consolidation were significantly increased in the progressive and peak stages (for all, P<0.001). CT score was significantly correlated with the pneumonia volume in the four stages (r = 0.731, 0.761, 0.715, and 0.669, respectively, P<0.001).  
Conclusion: 3D-CT could be used as a useful quantification method in monitoring the dynamic changes of COVID-19 pneumonia.