Siderotic nodules in the spleen: MR imaging of portal hypertension.

The authors retrospectively evaluated magnetic resonance (MR) images obtained at 1.5 T in 233 patients with portal hypertension and 91 subjects without it and pathologic findings in four resected spleens (one normal). Multiple, tiny (3-8 mm in diameter), low-intensity spots in the spleen were observed in 21 of 233 patients. Among the imaging studies performed in these 21 patients, the spots were seen on five of 14 T1-weighted images, 11 of 20 proton density images, and 12 of 20 T2-weighted images obtained with spin-echo techniques and on 14 of 14 fast-scan images obtained with gradient-echo rephasing. MR images in the 91 subjects did not show such lesions. MR images of the three spleens resected from patients with portal hypertension showed the low-intensity spots, which corresponded to siderotic nodules found at pathologic analysis. Despite limited pathologic confirmation, siderotic nodules (so-called Gamna-Gandy nodules) are considered the most likely cause of multiple low-intensity spots in the spleen.