ABSTRACT
BACKGROUND: About 10-20% of patients with Coronavirus disease 2019 (COVID-19) infection progressed to severe illness within a week or so after initially diagnosed as mild infection. Identification of this subgroup of patients was crucial for early aggressive intervention to improve survival. The purpose of this study was to evaluate whether computer tomography (CT) - derived measurements of body composition such as myosteatosis indicating fat deposition inside the muscles could be used to predict the risk of transition to severe illness in patients with initial diagnosis of mild COVID-19 infection. METHODS: Patients with laboratory-confirmed COVID-19 infection presenting initially as having the mild common-subtype illness were retrospectively recruited between January 21, 2020 and February 19, 2020. CT-derived body composition measurements were obtained from the initial chest CT images at the level of the twelfth thoracic vertebra (T12) and were used to build models to predict the risk of transition. A myosteatosis nomogram was constructed using multivariate logistic regression incorporating both clinical variables and myosteatosis measurements. The performance of the prediction models was assessed by receiver operating characteristic (ROC) curve including the area under the curve (AUC). The performance of the nomogram was evaluated by discrimination, calibration curve, and decision curve. RESULTS: A total of 234 patients were included in this study. Thirty-one of the enrolled patients transitioned to severe illness. Myosteatosis measurements including SM-RA (skeletal muscle radiation attenuation) and SMFI (skeletal muscle fat index) score fitted with SMFI, age and gender, were significantly associated with risk of transition for both the training and validation cohorts (P < 0.01). The nomogram combining the SM-RA, SMFI score and clinical model improved prediction for the transition risk with an AUC of 0.85 [95% CI, 0.75 to 0.95] for the training cohort and 0.84 [95% CI, 0.71 to 0.97] for the validation cohort, as compared to the nomogram of the clinical model with AUC of 0.75 and 0.74 for the training and validation cohorts respectively. Favorable clinical utility was observed using decision curve analysis. CONCLUSION: We found CT-derived measurements of thoracic myosteatosis to be associated with higher risk of transition to severe illness in patients affected by COVID-19 who presented initially as having the mild common-subtype infection. Our study showed the relevance of skeletal muscle examination in the overall assessment of disease progression and prognosis of patients with COVID-19 infection.
Subject(s)
COVID-19 , Humans , Retrospective Studies , Area Under Curve , Nomograms , ROC CurveABSTRACT
OBJECTIVES: To analyze the imaging features of coronavirus disease 2019 (COVID-19) in different periods, and summarize the characteristics with itsdevelopment. METHODS: We retrospectively analyzed the CT image data of COVID-19 patients diagnosed by nucleic acid test and CT examination in 57 patients in Zhuzhou Central Hospital and Zhuzhou First People's Hospital, and summarized the characteristics of CT imaging and the development of lesions. RESULTS: Most of the cases were characterized by peripheral distribution of lesions. A total of 37 cases (64.91%) were purely peripherally distributed, 16 cases (28.07%) coexisted with peripheral and mid-internal distribution, and 4 cases (7.02%) had simple mid-inner band distribution. In peripherally distributed cases, the long axis of the lesion was mostly parallel to the pleura in 36 cases (63.16%). In the case of inner-middle zone distribution, the long axis of the lesion was mostly parallel and surrounded the bronchial vascular bundle, or distributed along the lung lobules (31.58%). All cases had ground-glass-density foci, 31 cases (54.38%) had fine grid shadows in the lesions, 46 cases (80.70%) had thick vascular shadows in the lesions, and 23 cases (40.35%) showed signs of bronchial inflation. Among the 10 cases of "wrinkling shape" lesions in the first CT examination, except for 1 case without reexamination, the remaining 9 cases had different degrees of absorption in the second CT examination. Among the 26 cases of "wrinkling shape" lesions in the second CT examination, except for 11 cases without reexamination, the other 15 patients had different degrees of absorption in the third CT examination. CONCLUSIONS: The early CT manifestations of COVID-19 are mostly ground-glass-density foci distributed in the subpleural region, some of which are distributed near the bronchial blood vessel bundle and in the central area of the lobule. As the course of the disease progresses, there may be varying degrees of solid components in the lesion. When the lesions show a "wrinkling shape", it is often suggested that the lesions will evolve towards the direction of absorption. These characteristics are of great value in assisting clinical diagnosis and dynamically observing changes undersuch condition.