Non-invasive estimation of pulmonary hemodynamics from 2D-PC MRI with an arterial mechanics method.

Pulmonary Hypertension (PH) is a challenging cardiopulmonary disease diagnosed when the mean pulmonary artery pressure (mPAP) is greater than 20 mmHg. Unfortunately, mPAP can only be measured through invasive right heart catheterization (RHC) motivating the development of novel non-invasive estimates. Pulmonary hypertension patients (n = 7) and control subjects (n = 8) had 2D phase contrast (PC) MRI of the main pulmonary artery during rest and moderate exercise. A novel method utilizing arterial mechanics was used to estimate mPAP and other pulmonary hemodynamics measures from the 2D PC images. mPAP estimated from MRI was greater in the PH group than the control group at both rest (24 ± 10 vs 12 ± 5 mmHg) and exercise (40 ± 8 vs 17 ± 9 mmHg). Area under the curve (AUC) calculated from receiver operator curve (ROC) analysis showed MRI estimated mPAP had excellent diagnostic ability to diagnose PH patients vs control subjects at rest and exercise (rest AUC = 0.91 [0.76 - 1.0], exercise AUC = 0.96 [0.88 - 1.0]). These are promising proof-of-concept results that pulmonary hemodynamics could be non-invasively estimated from an MRI and arterial mechanics approach. Future studies to determine the clinical utility of this method are needed.