Nuclear magnetic resonance imaging in retroperitoneal fibrosis.

Three patients with biopsy-proven idiopathic retroperitoneal fibrosis were studied by computed tomography (CT) and nuclear magnetic resonance (NMR). The nuclear magnetic resonance images revealed the extent of the fibrous mass or plaque and showed that it involved the periaortic area in each case. The diagnostic information regarding the extent of the disease was similar to that derived from the x-ray CT. The NMR images demonstrated the relation of the fibrosis to the major retroperitoneal vessels in a fashion superior to CT. Furthermore, variation in intraluminal signals on multiple spin-echo parameters suggested the presence of abnormal flow in the vessel constricted by retroperitoneal fibrosis.