Magnetic resonance imaging in the evaluation of the retroperitoneum.

Magnetic resonance imaging techniques have made it possible to delineate a variety of pathologic processes in the retroperitoneum, including lymphadenopathy, atherosclerotic and aneurysmal disease of the aorta, congenital venous anomalies, and primary and secondary retroperitoneal neoplasms. The availability of multiplanar image display, the excellent soft tissue contrast resolution, and the fact that exogenous contrast materials are not needed are valuable assets of this imaging modality.