Magnetic resonance evaluation of mitral stenosis.

In order to study magnetic resonance (MR) abnormalities in mitral stenosis, electrocardiogram (ECG)-gated MR imaging was performed with a 2.0 T MR system in 41 patients with mitral stenosis before catheterization. Mean transverse diameter of the left atrium was 8.9 +/- 1.4 cm and anteroposterior diameter was 5.1 +/- 1.0 cm, indicating significant enlargement. Homogeneous or inhomogeneous flow-related signals in ventricular diastole were detected in the left atrial cavity in 32 cases (78%), and in the atrial appendage in 35 cases (85%). In 21 patients having a mean wedge pulmonary arterial pressure higher than 20 mm Hg, 20 patients (95%) showed flow-related signals in ventricular diastole. Other MR findings were mitral valve doming in diastole, flow-related signal in the pulmonary artery during systole, and left atrial thrombi.