Semi-Quantitative Analysis of Lung Perfusion SPECT/CT for Evaluation of Response to Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension.

Purpose: We aimed to investigate the response to balloon pulmonary angioplasty (BPA) in chronic thromboembolic pulmonary hypertension (CTEPH) using semi-quantitative analysis of lung perfusion SPECT/CT. Methods: This is a single-center retrospective study of patients with CTEPH who underwent BPA and pre- and post-BPA lung perfusion SPECT/CT between 2015 and 2022. Segmental defects on SPECT/CT were visually assessed and semi-quantitatively scored as 1 (large defect) or 0.5 (moderate defect) in accordance with modified PIOPED II criteria. The perfusion defect score was defined as (Σ segmental defect scores/18) × 100 (%). Associations between perfusion defect score and hemodynamic or functional parameters including WHO functional class, six-minute walking distance (6MWD), serum B-type natriuretic peptide (BNP), mean arterial pulmonary pressure (mPAP), pulmonary vascular resistance (PVR), and tricuspid regurgitation pressure gradient (TRPG) on echocardiography were statistically analyzed. Results: A total of 24 consecutive patients were included. The perfusion defect score significantly improved after BPA (median 58.3% vs. 47.2%, P < 0.001), in conjunction with the WHO functional class, 6MWD, serum BNP, mPAP, and TRPG. Perfusion defect scores were significantly correlated with 6MWD (rho = − 0.583, P < 0.001), serum BNP (rho = 0.514, P < 0.001), mPAP (rho = 0.583, P < 0.001), and PVR (rho = 0.575, P < 0.001). The improvement in the perfusion defect score was significantly associated with improvement in mPAP (rho = 0.844, P < 0.001). Conclusion: Our results suggest that semi-quantitative analysis of lung perfusion SPECT/CT can provide a potential imaging biomarker for monitoring the efficacy of BPA. [ABSTRACT FROM AUTHOR]