A fully automated pipeline for the extraction of pectoralis muscle area from chest computed tomography scans

Abstract

CT-derived pectoralis muscle area (PMA) measurements are prognostic in people with or at-risk of chronic obstructive pulmonary disease (COPD), but fully automated PMA extraction has yet to be developed. Our objective was to develop and validate a PMA extraction pipeline that can automatically: 1) identify the aortic arch slice; and 2) perform pectoralis segmentation at that slice.CT images from the Canadian cohort of obstructive lung disease (CanCOLD) study were used for pipeline development. Aorta atlases were used to automatically identify the slice containing the aortic arch by group-based registration. A deep learning model was trained to segment the PMA. The pipeline was evaluated in comparison to manual segmentation. An external dataset was used to evaluate generalizability. Model performance was assessed using the dice-sorensen coefficient (DSC) and PMA error.In total 90 participants were used for training (age=67.0±9.9 years; FEV1=93±21%predicted; FEV1/FVC=0.69±0.10; 47 men), and 32 for external testing (age=68.6±7.4 years; FEV1=65±17%predicted; FEV1/FVC=0.50±0.09; 16 men). Compared with manual segmentation, the deep learning model achieved a DSC of 0.94±0.02, 0.94±0.01 and 0.90±0.04 on the true aortic arch slice in the train, validation and external tests sets, respectively. Automated aortic arch slice detection obtained distance errors of 1.2±1.3 mm and 1.6±1.5 mm on the train and test data, respectively. Fully automated PMA measurements were not different than manual segmentation (p>0.05). PMA measurements were different between people with and without COPD (p=0.01), and correlated with FEV1%predicted (p<0.05).A fully automated CT pectoralis muscle area extraction pipeline was developed and validated for use in research and clinical practice.