Magnetic Resonance Imaging Manifestations of Focal Fatty Infiltration and Focal Fatty Sparing Lesions of Liver

Abstract

Objectives: To evaluate the manifestations of dynamic gadolinium-enhanced MR imaging for focal fatty infiltration and focal fatty sparing. Methods: Eighteen patients with focal fatty sparing and 13 patients with focal fatty infiltrations were prospectively included in the study. The lesions were detected by sonography and the patients were referred to receive MR imaging. Results: All of the 18 focal sparing lesions showed hyperintense in the opposedphase T1WI FFE images; while 16 showed isointense and 2 showed hypointense in the inphase images. In the 13 focal fatty infiltrations, 11 of them showed hypointense, 2 showed isointense in opposed-phase T1WI; while 4 showed hyperintense and 9 showed isointense in in-phase. The enhancement of focal fatty sparing is higher and focal fatty infiltration is lower than the adjacent liver parenchyma, but no significant difference is found. None of the 31 lesions showed contrast washout phenomenon in all the three phases of contrast enhanced dynamic MR study. Conclusions: The characteristics of focal fatty infiltration and focal fatty sparing in dual echo T1WI and no ”washout phenomenon” in gadolinium-enhanced dynamic T1WI could provide useful information in differential diagnosis among hepatic tumors and reduce unnecessary liver biopsy.