A comparison of noninvasive MRI-based methods of estimating pulmonary artery pressure in pulmonary hypertension

Purpose To assess the accuracy of several noninvasive MRI‐based estimators of pulmonary artery pressure by comparing them with invasive pressure measurement. Materials and Methods We compared five MRI methods with invasive pressure measurement by catheterization, in one group of pulmonary hypertension (PH) patients. Doppler echocardiography was included as a reference method. Main inclusion criterion was a mean pulmonary artery pressure above 25 mmHg at catheterization. MRI velocity quantification was used to obtain pulmonary flow acceleration and ejection times, and pulse wave velocity. The ventricular mass index was also assessed on MRI. Two commercially available 1.5‐T systems were used for this study. Results Data from 44 patients were analyzed. Correlation of acceleration time with mean pressure was: r = –0.21, P = 0.21, correlation of the acceleration/ejection time ratio with systolic pressure was: r = –0.26, P = 0.01. The ventricular mass index showed the best correlation with mean pressure, with r = 0.56, P < 0.001. Using the pulse wave velocity and the cross‐sectional area of the pulmonary artery, the mean pressure could not be estimated accurately. Conclusion Accurate estimation of pulmonary artery pressure in PH patients was not feasible by the MRI estimators studied. These noninvasive methods cannot replace right heart catheterization at this moment. J. Magn. Reson. Imaging 2005;22:67–72. © 2005 Wiley‐Liss, Inc.