Abstract
<title>Abstract</title> <p>Background This study aimed to analyze the correlation between quantitative CT (QCT)-based body composition and the low attenuation area percentage (LAA%), and to evaluate its predictive value for severe emphysema. Methods This retrospective study included 260 individuals who underwent chest CT with concurrent QCT assessment. Clinical data were collected, and they were divided into emphysema grades 0, 1, 2, and 3 based on LAA%. Differences in baseline characteristics and body composition among groups were compared. Spearman correlation analysis and gamma regression using generalized linear models were used to explore the correlation between QCT-related body composition and LAA%. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive value of QCT-related body composition for emphysema grade 3. Results Individuals with grade 3 emphysema had the lowest pectoralis major muscle cross-sectional area (PMcsa), pectoralis major muscle index (PMI), pectoralis major muscle density (PMD), subcutaneous fat content, total muscle area, and L1-2 vertebral volumetric bone mineral density (vBMD), and the highest pectoralis major muscle fat infiltration rate (P < 0.05). LAA% was significantly negatively correlated with PMcsa, PMD, PMI, subcutaneous fat content, total muscle area of the same-layer muscle group, and vBMD, and significantly positively correlated with the overall fat infiltration rate of the pectoralis major muscle (P < 0.05). The area under the receiver operating characteristic curve (AUC) for predicting grade 3 emphysema ranged from 0.733 to 0.887 across body composition parameters. Conclusion QCT-derived body composition parameters are correlated with LAA%, and several parameters show acceptable to good predictive performance for grade 3 emphysema.</p>