Abstract 17826: Demonstration of Abnormal Myocardial Mechanics in Pulmonary Arterial Hypertension Using a Novel Magnetic Resonance Tissue Phase Mapping Technique
Introduction: Cardiac MRI has become the gold standard method of assessing global biventricular function in patients with pulmonary arterial hypertension (PAH). However, there may be additional prognostic benefit from assessing the components of motion. This is difficult with traditional MRI techniques, so we implemented a novel MR tissue phase mapping (TPM) technique that measures biventricular longitudinal and radial velocities.
Methods: Respiratory self-gated TPM was performed using a rotating golden-angle spiral acquisition with retrospective cardiac-gating. TPM of a basal ventricular slice was acquired in 13 PAH patients and 13 age- and sex-matched healthy volunteers. Endocardial and epicardial ventricular borders were manually defined, and myocardial velocities were calculated on in-house software developed on the open source OsiriX platform.
Results: RV longitudinal and radial systolic velocities were lower in PAH compared to controls (radial S: 1.74 cm/s ± 1.13 vs. 2.18 ± 0.89, p<0.04; longitudinal S: 1.09 ± 1.55 vs. 1.99 ± 1.02, p<0.003). In addition, longitudinal E/A ratio was reduced (0.37 ± 1.42 vs. 1.53 ± 3.04, p<0.04) while radial E waves were absent in 5 (38%) PAH patients due to prolonged inward radial motion.
LV systolic and diastolic dysfunction also occurs in PAH (radial S: 1.74 cm/s ± 1.13 vs. 2.18 ± 0.89, p<0.04; radial E/A: 1.64 ± 1.47 vs. 2.3 ± 1.51, p<0.05). Visualization of motion vectors demonstrated obvious abnormalities in septal motion (figure 1).
Conclusions: We have shown that our novel TPM sequence offers a comprehensive assessment of myocardial motion. Biventricular radial and longitudinal systolic and diastolic dysfunction is evident in PAH. In some cases an abnormal period of post-systolic inward radial RV motion further impairs biventricular filling. Further study is required to evaluate the effect of treatment on these parameters, and the possible role for pacing applied to abnormal motion patterns.
- © 2013 by American Heart Association, Inc.