Gated MRI of cardiac and paracardiac masses: initial experience.

Ten cardiac and paracardiac masses were studied with magnetic resonance imaging (MRI) to evaluate the utility of this new method for determining the nature, location, and extent of such masses. The masses were intramural lesions (two cases), left atrial thrombus (one case), pericardial cysts (three cases), and mediastinal masses deforming and displacing the left atrium (two cases). ECG-gated images were obtained in all patients. In each of nine cases, MRI determined the location of the mass as intracavitary, intramural, or paracardiac, without the need for exogenous contrast material. It excluded the clinical diagnosis of cardiac tumor in one case. A combination of multislice transaxial, coronal, and sagittal images established the extent of the masses and the degree of impingement on cardiac structures. This initial experience suggests that MRI can provide as much information as echocardiography, computed tomography, and angiography combined in the evaluation of cardiac and paracardiac masses.