Hepatic Hemangiomas with Peritumoral Sparing of Fatty Infiltration in Hepatic Steatosis: Findings on Contrast-enhanced MR Imaging and on Sonography

ABSTRACT

PURPOSE: We wanted to determine the frequency of peritumoral sparing of fatty infiltration (PTSF) around hepatic hemangioma in hepatic steatosis and to evaluate the finding of these tumors on dynamic contrast-enhanced MR imaging and on sonography. MATERIALS AND METHODS: This study included 76 hemangiomas in 67 patients suffering with hepatic steatosis. A diagnosis of hemangioma was based on the histologic findings, hemangioma SPECT or a compatible enhancement pattern on the dynamic contrast-enhanced MR study. For chemical shifting, PTSF was defined when there wasn't any decrease in signal intensity of the liver parenchyma on the opposed-phase images as compared with the in-phase images, and this intensity appeared as a hyperintense area around the tumor. We evaluated the frequency of PTSF and we analyzed if the presence of PTSF was related to the tumor size, the rapidity of enhancement or an associated arterioportal shunt. Among those, sonographic images were available in 55 hemangiomas. We also evaluated the sonographic appearances of hemangiomas with PTSF. RESULTS: Of the 76 hemangiomas, PTSF was noted on the MR chemical-shift images in 57 hemangiomas (75%). There was no significant relationship between tumor size and the presence of PTSF (p=.578). However, this finding was more frequently found in high-flow hemangiomas than in the slow-flow ones (p=.0038) and it was also related to the presence of associated arterioportal shunt (p=.0158). Sonographically, hemangiomas with PTSF were commonly surrounded by a peritumoral low-echoic area (28/41, 68%); these tumors more frequently showed a thin high-echoic rim on sonography than did the tumors without this finding (p=.0055). CONCLUSION: PTSF is commonly seen in hemangiomas in hepatic steatosis patients. Hepatic hemangiomas with PTSF tend to show rapid enhancement on dynamic MR imaging and this is accompanied by arterioportal shunt. They tend to be seen as an iso- or low-echoic mass with a thin high-echoic rim on sonography, and the mass is commonly surrounded by a peritumoral low-echoic area.