Hepatic Hemangioma and Metastasis: Differentiation With Gadoxetate Disodium-Enhanced 3-T MRI

OBJECTIVE. The purpose of this study was to evaluate the gadoxetate disodium-enhanced MRI findings of hepatic hemangioma and to investigate the diagnostic performance in differentiating hepatic hemangioma and metastasis. MATERIALS AND METHODS. Images of 32 hepatic hemangiomas in 25 patients and of 29 hepatic metastatic lesions in 20 patients were retrospectively reviewed. Two independent readers interpreted hepatobiliary phase images alone, dynamic extracellular phase images alone, and combined hepatobiliary and dynamic extracellular phase images. MRI findings and performance with respect to the differential diagnosis of hemangioma and metastasis were assessed. RESULTS. During the hepatic arterial phase, 11 of the 32 hemangiomas (34%) exhibited early total enhancement, and nine (28%) exhibited peripheral nodular enhancement. A bright dot sign or minimal peripheral enhancement during the late dynamic phase was observed for a small number of lesions (6% and 28%, respectively). Twenty-three of the 29 metastatic lesions (79%) exhibited ring enhancement during the hepatic arterial phase. Twenty-nine hemangiomas (91%) and all of the metastatic lesions exhibited homogeneous or heterogeneous hypointensity during the hepatobiliary phase. The sensitivity, specificity, and area under the receiver operating characteristic curve for the detection of hemangioma were 76%, 81%, and 0.87 for the hepatobiliary phase alone; 97%, 88%, and 0.97 for the dynamic extracellular phase alone; and 97%, 88%, and 0.98 for the combination. Five nodules smaller than 1 cm (four hemangiomas, one metastatic lesion) that exhibited no enhancement during the arterial phase and minimal enhancement during the late dynamic phase were not differentiated. CONCLUSION. Gadoxetate disodium-enhanced MRI was found useful for differentiating hepatic hemangiomas and metastatic lesions, especially during the dynamic extracellular phase. Only a limited number of lesions smaller than 1 cm in diameter, which exhibited minimal enhancement on late dynamic phase images, were difficult to diagnose.