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Objectives The aim of this study was to develop a composite numerical model based on parameters from cardiac magnetic resonance (CMR) imaging for noninvasive estimation of the key hemodynamic measurements made at right heart catheterization (RHC). Background Diagnosis and assessment of disease severity in patients with pulmonary hypertension is reliant on hemodynamic measurements at RHC. A robust noninvasive approach that can estimate key RHC measurements is desirable. Methods A derivation cohort of 64 successive, unselected, treatment naive patients with suspected pulmonary hypertension from the ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Centre) Registry, underwent RHC and CMR within 12 h. Predicted mean pulmonary arterial pressure (mPAP) was derived using multivariate regression analysis of CMR measurements. The model was tested in an independent prospective validation cohort of 64 patients with suspected pulmonary hypertension. Surrogate measures of pulmonary capillary wedge pressure (PCWP) and cardiac output (CO) were estimated by left atrial volumetry and pulmonary arterial phase contrast imaging, respectively. Noninvasive pulmonary vascular resistance (PVR) was calculated from the CMR-derived measurements, defined as: (CMR-predicted mPAP – CMR-predicted PCWP)/CMR phase contrast CO. Results The following composite statistical model of mPAP was derived: CMR-predicted mPAP = –4.6 + (interventricular septal angle × 0.23) + (ventricular mass index × 16.3). In the validation cohort a strong correlation between mPAP and MR estimated mPAP was demonstrated (R2 = 0.67). For detection of the presence of pulmonary hypertension the area under the receiver-operating characteristic (ROC) curve was 0.96 (0.92 to 1.00; p Conclusions CMR imaging can accurately estimate mean pulmonary artery pressure in patients with suspected pulmonary hypertension and calculate PVR by estimating all major pulmonary hemodynamic metrics measured at RHC.

Quantitative magnetic resonance imaging provides a comprehensive and non-invasive assessment of the heart and lungs in patients with suspected pulmonary hypertension with the potential for accurate assessment of disease severity and response to treatment. Magnetic resonance imaging (MRI) can provide detailed reliable information of heart structure and function as the heart responds to elevated right ventricle afterload in patients with progressive pulmonary vascular disease; notably, progressive changes in right ventricle volume and function are of prognostic value independent of established biomarkers. This article reviews the current literature on MRI in pulmonary hypertension and also describes new and exciting developments in imaging of the heart, pulmonary vasculature and lungs, including assessment of myocardial changes with late gadolinium-enhanced imaging and T1 mapping, evaluating changes in the proximal pulmonary vasculature using image-based computational modelling and quantitative assessment of the capillary bed using MRI perfusion analysis.