Focal lesions of the spleen: preliminary results with fast MR imaging at 1.5 T.

Sixteen patients with splenic lymphoma and six with nonlymphomatous splenic lesions underwent magnetic resonance (MR) imaging, ultrasound (US), and dynamic CT. All patients were studied at 1.5 T with gradient echo sequences using a repetition time of 80 ms, echo time of 16 ms, and two pulse angles of 30 and 60 degrees. In 14 patients with lymphomatous lesions fast MR showed circumscribed areas of low signal intensity at both pulse angles. The lesion-to-spleen contrast was better on images acquired with a pulse angle of 30 degrees. For fast MR with pulse angles of 30 degrees, the mean lesion-to-spleen contrast was similar to US and contrast-enhanced CT. However, with fast MR the contrast showed a lower variability and was considerably better than with unenhanced CT. In one patient fast MR showed splenic involvement that was missed on both CT and US. The signal characteristics of lymphomatous, leukemic, and sarcoid involvement and of healed infarcts were similar and indistinguishable on fast MR images. Recent splenic infarctions (three cases) were, however, distinctly different, characterized by regions of high signal intensity at both pulse angles. The results of this preliminary study suggest that fast MR imaging is a promising diagnostic tool for the assessment of splenic disorders.