Computed tomography features associated with pneumothorax susceptibility in pectus excavatum: a retrospective case-control study of lobar morphometry, attenuation metrics, and machine-learning projection.
Authors
Affiliations (2)
Affiliations (2)
- Department of Thoracic and Cardiovascular Surgery, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Republic of Korea.
- Department of Anesthesiology and Pain Medicine, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu, Republic of Korea.
Abstract
Primary spontaneous pneumothorax (PSP) can occur without visible blebs or bullae, suggesting a broader structural susceptibility. Pectus excavatum (PE) is associated with a high incidence of PSP. We evaluated chest computed tomography (CT)-based lobar signatures of PSP and tested whether PE exhibits a PSP-like phenotype. Young adults aged 20-30 years were retrospectively grouped as first-episode PSP [patients with spontaneous pneumothorax (PT)], PE without prior pneumothorax, or healthy controls (HC). Using 3D Slicer<sup>®</sup>, we extracted lobar morphometric indices [volume, surface area (SA), surface area-to-volume ratio (SA/V), and shape descriptors] and Hounsfield unit (HU)-derived attenuation metrics from CT datasets. Group differences were assessed per lobe and by within-subject upper-lower asymmetry (Δ analysis). Five side-specific machine learning algorithms were trained to discriminate PT from HC using cross-validated predictions. Youden-optimal receiver operating characteristic (ROC) thresholds were applied to the PE cohort without retraining to quantify pneumothorax-like structural susceptibility. A total of 561 (right 282 and left 279) side-specific lobes were analyzed. PT showed higher SA/V and less compact lobar geometry than HC and broader high-attenuation tails. In Δ analyses, attenuation-based deltas consistently separated groups, whereas PE showed more geometry-driven asymmetry, including reduced Δ-flatness. support vector machine (SVM) discrimination was the most excellent [area under the curve (AUC): right 0.937; left 0.953]. At Youden thresholds (right 0.811; left 0.841), high-risk/PT-like classifications were enriched in PE versus HC (right 30/67 <i>vs.</i> 1/158; left 38/67 <i>vs.</i> 1/158; both P<0.001). Quantitative CT identifies distinct morphometric-attenuation phenotypes in PT and reveals a substantial PT-like signature in PE, warranting prospective validation with longitudinal pneumothorax outcomes.