Phase-Resolved Functional Lung (PREFUL)-MRI-derived parameters in evaluating chronic thromboembolic pulmonary disease: a prospective study

<bold>Background:</bold> Medical imaging is crucial in evaluating chronic thromboembolic pulmonary disease (CTEPD). Phase-resolved functional lung magnetic resonance imaging (PREFUL-MRI) is a radiation-free, contrast-agent-free, free-breathing, pulmonary functional imaging technique that provides information on pulmonary perfusion and ventilation. <bold>Objectives:</bold> To compare PREFUL-MRI-derived lung perfusion and ventilation metrics between patients with chronic thromboembolic pulmonary hypertension (CTEPH) and CTEPD without pulmonary hypertension (PH) and investigate the correlation between functional metrics and clinical severity. <bold>Methods and Main Results:</bold> Patients with CTEPD were prospectively enrolled and underwent PREFUL-MRI and right heart catheterization. We enrolled 118 patients with CTEPD, including 86 with CTEPH (median age 62 years [range, 42–67]) and 32 without PH (median age 46 years [range 33–67]). Among perfusion metrics, total perfusion defect percentage (QDPtotal) was highly correlated with pulmonary vascular resistance (ρ=0.63, P<0.001) and moderately correlated with 6‐minute walking distance (ρ=0.55, P<0.001), N-terminal pro-brain natriuretic peptide (ρ=0.58, P<0.001) and World Health Organization functional class (ρ=0.55, P<0.001). CTEPH patients had higher QDPtotal compared with CTEPD without PH (36.4% [21.7%–57.0%] vs 7.6% [5.1%–16.3%]; P<0.001). Areas under receiver operating characteristic curves showed QDPtotal for CTEPH diagnosis and risk stratification were 0.860 and 0.804, respectively. And a QDPtotal cutoff value of 19.3% indicated PH. <bold>Conclusions:</bold> PREFUL-MRI quantified the regional perfusion metrics, exhibiting its potential value in evaluating CTEPD. <fig><object-id>erj;64/suppl_68/OA5554/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <fig><object-id>erj;64/suppl_68/OA5554/F2</object-id><object-id>F2</object-id><object-id>F2</object-id><graphic></graphic></fig>