Early CT imaging markers of COVID-19 progression

Background: Early recognition of patients who are prone to develop severe or critical COVID-19 pneumonia may improve its management and modify its outcome by better treatment regimens. Objective: To investigate Computed Tomography (CT)-based early markers of COVID-19 progression. Material and methods: Thirty-two COVID-19 patients were retrospectively enrolled, including 23 moderate cases who remained moderate until being cured and discharged from hospital, and 9 progressive cases who started with moderate pneumonia and later progressed to severe or critical pneumonia. Clinical and CT data in the early course of disease were reviewed and compared. The association between early features and progression of COVID-19 were analyzed. Results: The multivariate logistic regression analysis revealed that the progression of COVID-19 were significantly associated with older age and higher CT score of the right lower lobe in the early CT images. After adjustment for relevant covariates, the relationship between CT score of the right lower lobe and COVID-19 progression persisted (odds ratio 19.28, 95% confidence interval 1.07 - 348.34). Conclusions: Higher CT Score of the right lower lobe in early images and older age appeared to be promising biomarkers for early prediction of COVID-19 prognosis. Extensive involvement of the right lower lobe at the early stage may suggest a high risk of progression. high total CT scores of lymphnode enlargement, pericardial effusion, images showed and fan-shaped consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped GGO, consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped GGO, consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped GGO, consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped GGO, and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped GGO, consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped GGO, and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped GGO, and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped GGO, consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped pure GGO, GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped pure GGO, GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed and fan-shaped GGO, and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal and fan-shaped GGO, and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of right upper lobe and right lower lobe (white arrow). Thickening of pleura and pleural retraction (white arrowhead, A) were also present. E, F. 32-year-old man. Baseline CT images showed round and fan-shaped pure GGO lesions in peripheral area of both lower lobes (white arrow). G, H. 38-year-old woman. Baseline CT images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.CT features of COVID-19 Pneumonia. This figure shows CT features indicating the number, involvement, distribution, shape, and density of the lesions, pleura and interstitial changes caused by COVID-19 Pneumonia. A–D. 15-year-old woman. Baseline CT images showed multifocal round pure ground-glass opacities (GGO), consolidation, and mixed GGO lesions in peripheral and central area of images showed multifocal irregular and fan-shaped pure GGO, mixed GGO and consolidation, and consolidation lesions in peripheral and central area of all the lobes of both lungs (white arrow). I–L. 47-year-old woman. Baseline CT images showed multifocal rectangular, fan-shaped, round, and irregular mixed GGO lesions in peripheral area of all the lobes of both lungs (white arrow). The interlobular septal thickening in regions of lesions and microvascular dilation sign were also present.


Introduction
Emerging in late December 2019 in Wuhan, China, coronavirus disease 2019 (COVID-19) has rapidly spread to 199 countries around the world and become a global health threat. As of March 28, 2020, there had been 522343 confirmed cases and 24531 deaths worldwide [1,2]. The causative agent was identified to be a novel coronavirus currently termed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [3]. Although most of people with COVID-19 have a mild clinical course, severe pneumonia occurred in 15.7% of cases [4]. Severe and critical COVID-19 patients have higher incidences of acute respiratory distress syndrome (ARDS) and serious complications, and have a high likelihood of admission to intensive care [5]. It has been reported that the mortality of severe COVID-19 is high (28%-62%) [6-8], and even higher (81%) among those requiring mechanical ventilation [6,9]. Treatment of severe and critical COVID-19 patients remains an arduous challenge in current clinical practice [6].
Early recognition of patients who are prone to develop severe and critical COVID-19 may improve its management and modify its outcome by better treatment regimens. Therefore, early prediction of progression is of utmost importance. Practicable biomarkers of evolving illness severity are urgently required to enable timely intervention. Chest computerized tomography (CT) provides a powerful noninvasive mean for the diagnosis and treatment monitoring for COVID-19, which shows diverse patterns with both lung parenchyma and interstitium involved. However, the correlation between CT findings and clinical progression, and the predictive value of baseline CT for disease outcome are not well understood as of to date [10][11][12][13]. Therefore, in this study, we compared the differences of baseline CT features of moderate and progressive patients at the onset of COVID-19 pneumonia, exploring potential imaging marker tracking COVID-19 progression since the early stage of the disease.

Material And Methods
This retrospective study was approved by the Institutional Review Board of People's Hospital of Guangxi Zhuang Autonomous Region, and the requirement for informed consent was waived.

Study Subjects
We performed a retrospective review of 32 consecutive patients with COVID-19 in People's Hospital of Guangxi Zhuang Autonomous Region from January 2020 to March 2020. The diagnosis was The patients were grouped based on the illness severity defined by the National Health Commission of China. The severe/critical cases met at least one of the following [14] :1) breathing rate ≥ 30 breaths per minute; 2) pulse oximeter oxygen saturation ≤ 93% in a resting state; 3) arteria oxygen tension (PaO 2 )/inspiratory oxygen fraction (FiO 2 ) ≤ 300 mmHg; 4) respiratory failure (PaO 2 < 60 mmHg when breathing ambient air) occurred and mechanical ventilation required; 5) hemodynamic shock; 6) patients with other organ failure needed intensive care unit monitoring and treatment. Five mild patients with normal CT were not included in the study, so the rest cases were place in moderate group.

Data Collection
Data included age, gender, comorbidities (hypertension, diabetes mellitus, heart disease, cerebrovascular diseases, and chronic obstructive pulmonary disease), symptoms, clinical sign, laboratory findings, and CT images were obtained from medical records. Both clinical and radiological parameters at the initial stage were used to gather information on early features that may be related to COVID-19 progression. Time from initial CT examination to severe/critical pneumonia development, and time from symptom onset to severe/critical pneumonia development were calculated.

Image Viewing And Evaluation
Three chest radiologists with 6, 9 and 11 years of experience who were blinded to the clinical data evaluated the CT findings in consensus. For each of the 32 patients, the initial chest CT images were analyzed for the following points: 1) number of the lesions, indicated as single lesion or multiple lesions; 2) site of the lesions, indicated as right upper lobe (RUL), right middle lobe (RML), right lower lobe (RLL), left upper lobe (LUL), and left lower lobe (LLL); 3) range of lobe involvement: indicated as single lobe involvement, 2 lobes involvement, 3 lobes involvement, 4 lobes involvement, and 5 lobes involvement; 4) transverse distribution of the lesion: described as peripheral, central, and peripheral and central; 5) lesion density, described as ground glass opacity (GGO), consolidation, mixed GGO and consolidation; 6) types of lesion density: classified as 1, 2, and 3; 7) shape of the lesion: described as round, fan-shaped, rectangular, bat-wing, and irregular; 8) other following characteristics: interlobular septal thickening, air bronchogram, microvascular dilation sign, fibrotic streaks, pulmonary emphysema, thickening of pleura, pleural retraction sign, pleural effusion, and lymphadenopathy; 9) extent of lesions: to quantify the extent of lesions and the degree of involvement, a thin section CT score was assigned on the basis of all abnormal areas involved. Each lobe was assigned a score that was based on the following: score 0, denoted no involvement; score 1, < 25% involvement; score 2, 25% to less than 50% involvement; score 3, 50% to less than 75% involvement; and score 4, ≥ 75% involvement. There was a score of 0-4 for each lobe, with a total possible score of 0-20(Figs. 1 and 2).

Statistical Analysis
All statistical analyses were performed with the SPSS 17.0 software package (SPSS Inc., Chicago, IL, United States). Categorical variables were described as frequency rates and percentages, and quantitative variables were described using mean ± SD or median (inter quartile range, IQR) values.
The Fisher exact test were used for categorical variables. For quantitative variables, independent sample t test was used for normally distributed data, and Mann-Whitney U test was used for nonnormally distributed data. Subsequent univariate and multivariate logistic regression analysis were performed to further identify the initial clinical parameters and baseline CT features associated with the progression of COVID-19 pneumonia. P-values < 0.05 were considered significant.

Clinical Characteristics
A total of 32 patients were included in the study, 9 (28.1%) were progressive cases who later progressed from moderate cases to severe/critical cases, and 23 (71.9%) were moderate cases who remained moderate until being cured and discharged. The clinical characteristics of the patients are shown in Table 1. The mean time from initial CT examination to severe/critical pneumonia development was 5 days, and that from symptom onset to severe/critical pneumonia development was 9 days. White blood cell count(× 10 9 /L) 6.6 ± 2.0 6.9 ± 1.8 Hemoglobin ( Compared with the moderate group, the progressive cases were significantly older (mean age 61.1 ± 15.2 years vs 35.8 ± 13.6 years; P < 0.01) and had more comorbidities of hypertension, diabetes mellitus, and cerebrovascular diseases (P = 0.02). No significant differences were observed in gender, oxygenation index, white blood cell count, hemoglobin, neutrophil ratio, lymphocyte ratio, creatinine, and erythrocyte sedimentation rate between the two groups.

Ct Findings
There were significant differences between the two groups in the total CT score of both lungs (P < 0.01), the CT scores of each lung lobe, and incidence of right middle lobe involvement (P < 0.01) and all lobes involvement (P < 0.01).
No significant differences were observed in number of the lesions, transverse distribution of the lesion, lesion density, shape of the lesion, interlobular septal thickening, air bronchogram, microvascular dilation sign, fibrotic streaks, pulmonary emphysema, thickening of pleura, pleural retraction sign, pleural effusion, and lymphadenopathy between the two groups. The CT Features were present in Table 2.

Discussion
The severe/critical patients have worse prognosis and higher mortality than the moderate patients.
Therefore, it is essential to perform active intervention for COVID-19 cases who are more likely to progress before developing into severe/critical stages, and the key lies in the early assessment of potential risk of progression [15]. This study demonstrated that older age and higher CT score of right lower lobe in the early images were risk factors for the progression of COVID-19. They may be promising biomarkers for predicting the progression of COVID-19. Such an early identification of patient at risk of progression would be of paramount clinical importance, because it could allow for the design and implementation of personalized preventive and therapeutic strategies, thereby improving the prognosis and reducing the mortality.
In this study, we found that older age was risk factor for the progression of COVID-19 pneumonia.
Previous studies have generally assumed that the elderly were more seriously ill after infection [1,6,7,16,17]. Older people are more likely to develop disease progression, which may be the result of their weakened immune function [5]. In our study, the rate of underlying disease was significantly associated with the progression based on univariate logistic regression analyses, but subsequent multivariate analysis negated the significance of it. Some previous studies on COVID-19 pneumonia showed that the rate of underlying disease was not significantly different between nonemergency group and emergency group [17]. However, some other previous studies showed that people with underlying disease were more seriously ill after infection [16]. The differences between these studies may have been due to patients selection bias, sample sizes, different research parameters, and different statistical methods (e.g., some of these studies did not use multivariate analysis).
Most patients with COVID-19 pneumonia had GGO or mixed GGO and consolidation, interlobular septal thickening, and vascular enlargement in the lesion, and the lesions were more likely peripheral distribution, bilateral involvement, and multifoca [12, 13, 18-22]. In our study, above CT features of COVID-19 pneumonia were not associated with the progression, indicating that above CT features in early-phase were not risk factors of the progression of COVID-19 pneumonia. Some previous studies showed that the CT findings of consolidation, linear opacities, crazy paving pattern, bronchial wall thickening, high total CT scores of involvement, lymphnode enlargement, pericardial effusion, and pleural effusion were features of severe/critical COVID 19 pneumonia, and were related to the severity of disease [16]. In this study, above CT features of severe/critical COVID-19 pneumonia were not associated with the progression based on initial baseline Chest CT. However, the CT score of right lower lobe in the early images was strongly related to the progression, independently of the age. It is unclear at this time why more severe involvement of right lower lobe in the early images was associated with COVID-19 deterioration. The phenomenon may be related to the deeper location and higher load of the culprit virus. Since the right mainstem bronchus is shorter, wider, and more vertical Previous studies showed that there were many differences in laboratory indicators between COVID-19 pneumonia and non-COVID-19 pneumonia patients, or between the moderate and severe/critical COVID-19 pneumonia patients [1, 5-7, 12, 16]. However, in our study, these initial laboratory indicators of oxygenation index, white blood cell count, hemoglobin, neutrophil ratio, lymphocyte ratio, creatinine, and erythrocyte sedimentation rate were not associated with the progression of COVID-19 pneumonia.
This study has several limitations. Firstly, data of the two groups were not balanced. The sample size of the progressive group was limited because most severe/critical patients presented with rapid deterioration and their early data was unavailable. Further studies with more patients especially progressive cases are warranted. Secondly, we had not performed further investigation of the pulmonary lesions early in the course of the disease, due to the lack of inspection equipment in temporary isolation wards. Bronchoscopy, bronchoalveolar lavage and lung biopsy are required to further confirm the nature of the lesions.

Conclusion
According to our findings, Higher CT Score of the right lower lobe in the early images and older age appeared to be promising biomarkers that may potentially be useful for early prediction of COVID-19 prognosis. Extensive involvement of the right lower lobe at the early stage may suggest a high risk of progression. Further prospective studies are required to confirm and interpret the association.   and 1, respectively. The total CT score of both lungs was 8.