Role of high-resolution computed tomography in assessment of the pectoralis muscle and correlation with the pulmonary function test in patients with interstitial lung disease

Abstract Background Muscle dysfunction in ILD has been previously documented and observed a more significant decrease in both muscle strength and size among individuals with ILD compared to healthy subjects. The classical pattern on spirometry in ILD is a restrictive ventilator abnormality with decreased FVC and normal or increased FEV1/FVC ratio with preserved FEV. While using quantitative CT measurements in patients with ILD, they demonstrated clinically relevant associations between PMA and indicators of ILD severity. Specifically, they noted that patients with ILD who had the lowest PMA had the most severe restrictive ventilator defect. The special reconstruction algorithm in AI graphics software is used to automatically measure the distribution of skeletal muscle components and adipose tissue in different levels, and individual muscle groups on CT images with high precision, to achieve a quantitative assessment of muscle mass. Aim of the work : This study aims to determine the ability of HRCT assessment of pectoralis muscle area and pectoralis muscle density to determine the severity of ILDs and change in pulmonary function test in patients with ILDs. Patients and methods The study was conducted from November 2024 to July 2025. Fifty patients having ILDs were enrolled in our study. HRCT and PFT were performed for all participants. PMA and PMD were measured from a single axial slice of chest CT above the aortic arch at baseline. The generalized linear model was used to determine the correlation between PMA and PMD measurements and PFT. Results There are statistically significant positive correlations between pulmonary function tests and PMD measurement ( P < 0.05). There are no significant positive correlations between pulmonary function tests and PMA measurement ( P > 0.05). Conclusion HRCT-derived pectoralis muscle density better reflects functional status and pulmonary function than muscle size in ILD, with AI-based analysis providing rapid reproducible assessment.