Regional ventilation–perfusion changes after endobronchial valve therapy assessed by single-photon emission computed tomography in adults with severe COPD

Bronchoscopic lung volume reduction (BLVR) is an established treatment for patients with severe chronic obstructive pulmonary disease (COPD), characterized as emphysema and hyperinflation, but current methods of patient selection and lobe identification are limited due to invasiveness, lack of specificity, and poor regional ventilation and perfusion assessments. This study aimed to evaluate lobar changes in ventilation, perfusion, and volume before and after endobronchial valve (EBV) placement using SPECT/CT imaging in patients with severe emphysema, and to assess their association with clinical outcomes. A prospective, single-center, pilot study enrolled six patients with severe COPD (FEV₁ ≤ 50%), and hyperinflation on pulmonary function tests (PFTs). Additionally, participants had severe heterogeneous emphysema (≥ 70% with voxel density ≤ - 910 Hounsfield units), and adequate fissure integrity (≥ 95%), both quantified by StratX™. All participants underwent BLVR in a single target lobe and received pre- and post-procedure SPECT/CT imaging using nebulized ^99mTc inhaled in the upright position to assess ventilation followed by ^99mTc-macroaggregated albumin injection to assess perfusion. Ventilation, perfusion, and volume were quantified at the target, adjacent, and contralateral lobes using AutoLung 3D software. PFTs and six-minute walk tests (6MWT) were obtained before and after BLVR. Treated lobes demonstrated a significant reduction in ventilation (66.7% [IQR 47.1-88.2]), perfusion (71.9% [63.1-78.8]), and volume (26.2% [10.4-35.3]) after BLVR. Adjacent lobes exhibited compensatory increases in ventilation (16.7% [8.5-51.3]), perfusion (+ 22.9% [19.7-33.9]), and volume (+ 12.6% [8.0-17.4]), while changes in contralateral lobes were minimal. These physiological changes weakly correlated with FEV₁ and 6MWT, which may suggest a disconnect between regional physiological adaptation and functional capacity. While prior studies have evaluated baseline physiology with SPECT/CT prior to BLVR, this is the first study to use this novel imaging to assess physiological responses after BLVR. SPECT/CT is a promising tool for evaluating lobar-level physiological responses to BLVR. Larger, multicenter studies with long-term follow-up are needed to validate its utility in patient selection, procedural planning, and outcome prediction following BLVR.