Submillimeter-pixel MR images of hepatic cavernous hemangiomas.

Several criteria have been used for differentiating hepatic cavernous hemangioma from other tumors at magnetic resonance imaging (MRI). Included are signal intensity and lobulation of the tumor. We counted the frequency of presence of lobulation of liver hemangiomas on T2-weighted images (T2WI), and measured the signal-intensity ratio (SIR) on T1-weighted images (T1WI) and on T2WI with a 0.9 mm x 0.9 mm pixel size using a 0.5 T magnetic resonance system. Eighty-three cavernous hemangiomas in 44 patients and 67 malignant tumors in 44 patients were retrospectively studied. Seventy-five of the cavernous hemangiomas (90%) exhibited lobules of various sizes, and four of the malignant tumors (6%) exhibited lobulations. The cavernous hemangiomas had a significantly higher SIR than the malignant tumors on T2WI: 3.0 +/- 0.7 and 1.9 +/- 0.8 (p < 0.001), respectively. The presence of lobulation together with a high SIR was a useful measure for differentiating cavernous hemangiomas from other liver tumors.