Diagnostic Methods Magnetic Resonance Imaging

Magnetic resonance (MR) imaging was performed in 14 patients with intracavitary cardiac tumors diagnosed by echocardiography. Except in the patients whose echocardiograms were diagnostic of atrial myxomas, this modality contributed important additional anatomic information regarding the tumor's relationship to the normal intracardiac structures and/or its extension to the adjacent vascular and mediastinal structures. The MR findings correlated extremely well with the findings in all 12 patients who underwent surgical exploration or postmortem examination, and in the other two patients, MR guided the decision to obtain transvenous biopsy samples of their right heart masses. Circulation 77, No. 1, 96-103, 1988. SINCE the characterization of left atrial myxoma by M mode echocardiography as a mobile echogenic density entering the mitral valve orifice in diastole, cardiac ultrasound has been the technique of choice for the evaluation of intracardiac tumors.' The introduction of two-diinensional echocardiography clarified the characteristic relationship of this tumor to the interatrial septum,2 and this ultrasonic imaging modality has provided excellent detail of the origin and extent of other intracavitary tumors arising from and limited to the heart. 3 Magnetic resonance (MR) imaging is a newer technique that enables high-resolution tomography in three dimensions. It is nonionizing, and generates intravascular and soft tissue contrast without the need for contrast mediuin. In the last few years. this modality has become available clinically for noninvasive body imnaging. More recently, electrocardiographic gating has tnade possible the high-resolution depiction of cardiac morphology, making magnetic resonance a promising technique in the evaluation of cardiac neoplasms . While the most common cardiac tumor, left atrial myxoma, is ordinarily exclusively intracavitary, other From the Departments of Medicine and Radiology. New York University Medical Center, New York, and the Department of Radiology, Albert Einstein College of Medicine, Bronx, NY. Address for correspondence: Itzhak Kronzon, M.D.. 560 First Ave. -Suite 2E, New York NY 10016. Rcceived July 30. 1987. accepted Ot 1987 96 tumors may have an extracavitary origin or extension, and may not be visualized in their entirety by standard M mode or two-dimensional echocardiography. We therefore assessed the contribution of MR imaging to the diagnostic evaluation of intracardiac tumors initially detected by echocardiography. Materials and methods Between 1984 and 1987, 14 patients whose intracavitary tumors were detected by echocardiography underwent magnetic resonance imaging. This group included eight men and seven women from 16 years to 74 years of age who were referred to the echocardiography laboratory for the clinical indications that are listed in table l. M mode echocardiograms and two-dimensional images were obtained in the parasternal long-axis, parasternal short-axis, and apical four-chamber views with the use of ATL MK600. and/or Toshiba SSH-65A, commercially available equipment. When the standard views demonstrated an intracavitary mass, attempts were made by use of subxiphoid. suprasternal, and other less standard views to image the entire extent of the tumor, as well as the great arteries, venae cavae, and pulmonary veins. Patients whose masses had the characteristics of thrombus arising from the mural surface of a left ventricular segmental wall motion abnormality, a globally myopathic left ventricle, or an enlarged or fibrillating left atrium with concomitant mitral valve disease6 7 were not included in this study. The MR studies were performed in the 14 patients with a Phillips Gyroscan S5 0.5 tesla superconducting system or a Technicare 0. 15 tesla resistive magnetic imager in the spin-echo mode. The studies were electrocardiographically gated, and all patients in the study were in sinus rhythm without significant ectopy. All 14 patients included in this study had anatomic confirmation and histopathologic diagnosis of their tumor masses by CIRCULATION by gest on A ril 8, 2017 http://ciajournals.org/ D ow nladed from DIAGNOSTIC METHODS-MAGNETIC RESONANCE IMAGINCG surgical resection, percutaneous transvenous biopsy, or postmortem examination.