Evaluation of Pulmonary Hypertension Using <scp>4D</scp> Flow <scp>MRI</scp>

BACKGROUND Cardiac magnetic resonance imaging (MRI) is becoming an alternative to right heart catheterization (RHC) for evaluating pulmonary hypertension (PH). A need exists to further evaluate cardiac MRI&#39;s ability to characterize PH. PURPOSE To evaluate the potential for four-dimensional (4D) flow MRI-derived pulmonary artery velocities to characterize PH. STUDY TYPE Prospective case-control. POPULATION Fifty-four PH patients (56% female); 25 controls (36% female). FIELD STRENGTH/SEQUENCE 1.5 T; gradient recalled echo 4D flow and balanced steady-state free precession cardiac cine. ASSESSMENT RHC was used to derive patients&#39; pulmonary vascular resistance (PVR). 4D flow measured blood velocities at the main, left, and right pulmonary arteries (MPA, LPA, and RPA); cine measured ejection fraction, end diastolic, and end systolic volumes (EF, EDV, and ESV). EDV and ESV were normalized (indexed) to body surface area (ESVI and EDVI). Parameters were evaluated between, and within, PH subgroups: pulmonary arterial hypertension (PAH); PH due to left heart disease (PH-LHD)/chronic lung disease (PH-CLD)/or chronic thrombo-emboli (CTE-PH). STATISTICAL TESTS Analysis of variance and Kruskal-Wallis tests compared parameters between subgroups. Pearson&#39;s r assessed velocity, PVR, and volume correlations. Significance definition: P