Abstract Rationale Pneumothorax (PTX) is the most frequent complication following bronchoscopic lung volume reduction (BLVR). Although lobar volume and emphysema severity have been studied, quantitative CT (QCT) parameters that predict PTX remain poorly defined. This study sought to identify pre-procedural QCT metrics, specifically air-trapping parameters, that may predict PTX development from inspiratory and expiratory imaging. We aimed to determine whether the degree of air trapping within ipsilateral non-target lobes—reflecting their potential fragility—was associated with subsequent PTX after BLVR. Methods A retrospective analysis was performed on 59 patients (27 with PTX, 32 without) who underwent BLVR. Pre-procedure inspiratory and expiratory CT scans were analyzed using Coreline software to quantify lobar volumes and air-trapping metrics. Parameters included target lobe absolute and percent volume, fissure completeness, ipsilateral non-target lobe volume, change in ipsilateral non-target volume (ΔVnt), change in mean lung density (ΔMLD), percentage change in low-attenuation area below -950 HU (Δ%LAA-950), and percentage of voxels below -856 HU (%LAA-856). Functional air trapping (fAT) was defined as the proportion of lung voxels demonstrating air retention between paired inspiratory and expiratory CT scans. Group comparisons were assessed using t-tests or Mann-Whitney U tests as appropriate. Variables with significant or near-significant differences were further analyzed with univariate logistic regression. Results Among all evaluated variables, the product of target lobe volume and ipsilateral non-target lobe fAT demonstrated a statistically significant association with post-BLVR PTX (univariate logistic regression p = 0.049; odds ratio 1.014, 95% CI 1.000-1.029). Trends toward higher fAT (p = 0.055) and greater %LAA -856 (p = 0.055) were observed among patients who developed PTX, whereas fissure completeness, ΔVnt, ΔMLD, and Δ%LAA-950 did not differ significantly between groups (p 0.1). Neither target lobe volume nor fAT alone remained significant on multivariate analysis. Detailed variable comparisons are presented in Table 1. Conclusions Pre-procedural QCT analysis identified that the interaction between target-lobe size and air trapping of ipsilateral non-target lobes is the strongest correlate of post-BLVR pneumothorax. This composite metric may represent a physiologic parameter reflecting redistribution of volume into gas-trapped adjacent lobes. Prospective validation in larger cohorts is warranted. This abstract is funded by: None
Albaba et al. (Fri,) studied this question.