4D-Flow MRI-Derived Wall Shear Stress as a Non-Invasive Biomarker for the Detection and Hemodynamic Characterization of Pulmonary Hypertension

Ben Statton, Chlöe Armour, Kai'en Leong, Jan Sedlacik, Alaine Berry, Ning Jin, Daniel Giese, Francesco Lo Guidice, Luke Howard, Deepa Gopalan
https://doi.org/10.1002/pul2.70426

Abstract

Invasive right heart catheterization (RHC) remains the reference standard for diagnosing pulmonary hypertension (PH), but there is a pressing need for non-invasive techniques to assess pulmonary hemodynamics. This study evaluates 4D-flow MRI-derived wall shear stress (WSS) for PH detection using the updated 2022 hemodynamic criteria, and the prediction of right ventriculo-pulmonary arterial (RV-PA) uncoupling to assess disease severity. 3D WSS was measured in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in a retrospective validation cohort (41 PH patients, 23 non-PH) and then assessed in a prospective test cohort (23 PH patients, 17 healthy controls). For methodological validation, a patient-specific computational fluid dynamics (CFD) was performed in a subset of 16 patients from the validation cohort. RV-PA uncoupling was assessed on the cine MRI, using RV global longitudinal strain (GLS) < −15.3% and RVSV/RVESV < 1. Both 3D peak and time-averaged WSS were significantly reduced in PH patients compared with healthy controls. Global WSS metrics demonstrated the strongest correlations with invasive hemodynamic parameters, including mPAP (r = −0.75, p < 0.001) and PVR (r = −0.76, p < 0.001). ROC curve analysis identified a peak WSS cutoff of < 0.30 Pa (AUC 0.98) for PH detection, a threshold achieving 90% sensitivity and 100% specificity in the test cohort. Furthermore, a peak WSS threshold of < 0.18 Pa demonstrated excellent discriminative ability for RV-PA uncoupling. These findings support the potential integration of WSS analysis into routine CMR protocols as a non-invasive complement to RHC, showing promise for both diagnosis and a longitudinal biomarker for monitoring PH.

Read the full research article