Magnetic resonance imaging of the pericardium: normal and pathologic findings.

Twenty normal subjects and ten patients with pericardial abnormalities underwent ECG-gated magnetic resonance (MR) imaging of the thorax using a 0.35-tesla superconducting system. The patients with pericardial abnormalities were also evaluated with serial chest radiographs, ultrasound, computed tomography, and/or angiography. ECG gating was necessary to identify the normal pericardium, which was visualized as a 1- to 2-mm-wide curvilinear structure of low signal intensity. Pericardial thickening in constrictive pericarditis was clearly delineated on gated MR images. Pericardial inflammation caused a marked increase in signal intensity as well as thickening of the pericardium. Pericardial effusions and pericardial adhesions were also demonstrated. A simple pericardial cyst and a complex pericardial mass were identified and differentiated from pericardial fat and diaphragmatic eventration. MR appears to be an important modality for the evaluation of pericardial disease.