Utility of phase contrast MR imaging for assessment of pulmonary flow and pressure estimation in patients with pulmonary hypertension: Comparison with right heart catheterization and echocardiography

Purpose: To compare the utility of phase contrast MR imaging (PC-MRI) for assessment of pulmonary flow and pressure estimation with that of right heart catheterization and echocardiography (cardiac US) in patients with pulmonary arterial hypertension (PAH). Materials and Methods: Twenty consecutive patients with suspected PAH underwent PC-MRI, cardiac US, and right heart catheterization. In each patient, PC-MRI was acquired by cine 2D-PC method on a 1.5 Tesla scanner, and stroke volume (SV) and pulmonary arterial systolic pressure (PASP) were assessed by using the modified Bernoulli's equation. To evaluate the agreements of SV and PASP among the three methods, correlations and limits of agreement among the three methods were statistically assessed by using the Bland-Altman's analyses. Results: The correlations and limits of agreement for SV and PASP between PC-MRI and catheterization (r = 0.96, r ² = 0.94, 1.1 ± 6.9 mL and r = 0.94, r² = 0.88, -3.2 ± 14.5 mmHg, respectively) were better than between cardiac US and catheterization (r = 0.01, r² < 0.01, 8.9 ± 42.1 mL and r = 0.86, r² = 0.72, -5.9 ± 27.7 mmHg, respectively). Conclusion: PC-MRI is more compatible with right heart catheterization than cardiac US in pulmonary flow and pressure estimation.