Magnetic resonance imaging in the diagnosis and followup of idiopathic retroperitoneal fibrosis.

Four cases of idiopathic retroperitoneal fibrosis are reported. Magnetic resonance and computerized tomographic images were obtained for diagnosis in each case, and followup scans were obtained at various intervals after therapy. In all 4 cases magnetic resonance imaging was equal or superior to computerized tomography in the diagnosis of retroperitoneal fibrosis, outlining the extent of involvement, preoperative planning and assessing response to medical or surgical therapy.