Splenic lymphoma: ferrite-enhanced MR imaging in rats.

Ferrite, a new magnetic resonance (MR) contrast agent, was evaluated in the detection and diagnosis of splenic lymphoma. Before administration of ferrite, normal rat spleens and spleens with diffuse lymphoma showed similar in vitro relaxation times and in vivo MR imaging signal-to-noise ratios (S/N). After the administration of ferrite (50 mumol Fe/kg), the T2 time of lymphomatous spleen was 27.0 msec +/- 2.9 (mean +/- standard deviation), which was significantly greater than that of normal spleen (10.7 msec +/- 1.5, P less than .005). The S/N of ferrite-enhanced in vivo MR images of lymphomatous spleen was 12.4 +/- 0.9, which was significantly greater than normal (5.7 +/- 0.2, P less than .005). Similar experiments with animal models of micronodular lymphoma also demonstrated that ferrite-enhanced MR imaging can distinguish micronodular lymphoma from normal spleen. Benign splenomegaly, studied with an animal model of erythroid hyperplasia, showed ferrite-enhanced MR tissue characteristics that were indistinguishable from those of normal spleen.