Magnetic Resonance Imaging of the Perirenal Space and Retroperitoneum.

Retroperitoneal diseases are frequently a great clinical challenge because of their nonspecific presentation. Diseases may be asymptomatic with indolent biological behavior, and often show a large mass at initial imaging evaluation. Magnetic resonance (MR) imaging is a powerful diagnostic technique for assessment of detailed disease location and for characterization of tissue components and vascularization of lesions, with many advantages compared with computed tomography and ultrasonography. This article presents the MR imaging features of common retroperitoneal pathologic processes.