MRI of perivalvular infectious pseudoaneurysms.

MRI demonstrated perivalvular infectious pseudoaneurysms in three patients who had infective endocarditis that complicated cardiac surgery. In each case the infectious pseudoaneurysm, or abscess cavity, demonstrated absence of MR signal, consistent with the free flow of blood between it and the vessel lumen. Cardiac-gated MR images showed the precise location of the three infectious pseudoaneurysms in relation to the cardiac chambers: One was between the aortic root and left atrium; another was in the outflow portion of the ventricular septum; and the third surrounded the Rastelli conduit. Noninvasiveness, independence from the need for IV contrast material, precision in determining the site of the infectious pseudoaneurysm, and the lack of image artifacts produced by prosthetic valves make MRI a useful technique for detecting infectious cardiac pseudoaneurysms.