Purpose: To retrospectively determine the findings of gadoxetic acid-enhanced magnetic resonance imaging (MRI) to distinguish hemangioma and metastasis of the liver.
Materials and methods: The University's ethics committee approved this retrospective study. We assessed 45 patients without chronic liver disease who underwent gadoxetic acid-enhanced MRI. Diagnosis of 58 metastases and 47 hemangiomas was confirmed using histopathology or multimodality evaluation. Two radiologists independently assessed the following MRI findings of metastasis and hemangioma: their appearance on T2-weighted images (T2WI) and dynamic contrast enhancement patterns after gadoxetic acid administration. The metastasis and hemangioma findings were compared using Fisher exact test. The lesion-to-liver signal intensity ratio on hepatocyte phase was compared using the Mann-Whitney U test. Multivariate analysis was performed to identify independent imaging findings distinguishing the 2 diseases. Receiver operating characteristic analysis was used to estimate the diagnostic ability of gadoxetic acid-enhanced MRI to distinguish metastasis from hemangioma.
Results: The lesion-to-liver signal intensity ratio was comparable in both diseases. Peripheral-dot enhancement, ring-like, geographic, and moderate late-phase enhancement, rapid contrast filling, and bright signal on T2WI could differentiate between the 2 diseases. In multivariate analysis, bright signal on T2WI (94%-98% in hemangioma and 13%-25% in metastasis) and ring-like enhancement (4% in hemangioma and 58%-60% in metastasis) were the independent findings suggesting hemangioma and metastasis, respectively. The areas under the receiver operating characteristic curves to distinguish metastasis from hemangioma were 0.95 and 0.98 for Reader 1 and 2, respectively.
Conclusion: Reliable findings to distinguish hepatic metastasis from hemangioma on gadoxetic acid-enhanced MRI were ring-like enhancement on arterial-phase images and bright signal on T2WI.