[Right ventricular function in cardiovascular disease evaluated by magnetic resonance imaging]

The usefulness of ECG-gated magnetic resonance imaging (MRI) in evaluating right ventricular architecture and function was assessed by measuring right ventricular wall thickness, wall motion, and areas of the right ventricular cavities of seven normal subjects and 46 with cardiac disease, including atrial septal defect (ASD: six cases), hypertrophic cardiomyopathy (HCM: 19), dilated cardiomyopathy (DCM: eight), and old myocardial infarction (OMI: 13 cases). A superconductive MRI system was used. Transverse images at the level of the tricuspid valve were obtained for measurements. ECG-gated MRI clearly showed the right ventricular myocardium throughout the cardiac cycles and facilitated measuring wall thickness and cross-sectional areas of the right ventricular cavity in all subjects. In normals the mean value and standard deviation of the anterior wall thickness of the right ventricle and the area index of the right ventricular cavity at end-diastole were 3.4 +/- 0.7 mm and 10.6 +/- 1 cm2/m2, respectively. The anterior and lateral walls and tricuspid annulus moved inward to the right ventricular cavity in systole, and the excursion of the lateral wall and tricuspid annulus was larger than those of the anterior wall. The interventricular septum (IVS), however, moved outward to the left ventricle in systole. The anterior wall thickness of the right ventricle in patients with HCM was 5.8 +/- 1.4 mm thicker than that of normal subjects. In contrast to normals, the area index of the right ventricular cavity was larger in patients with ASD (18.4 +/- 5.4 cm2/m2) and smaller in patients with HCM (9.1 +/- 1.6 cm2/m2). The IVS moved inward in all patients with ASD and in several patients with HCM. The anterior and lateral wall motion was decreased in patients with ASD and DCM.