Differentiation between inflammatory myofibroblastic tumor and colorectal liver metastasis on gadoxetic acid-enhanced MRI

Motivation: Inflammatory myofibroblastic tumors (IMT) of the liver can mimic malignant tumors, yet, they lack definitive radiological characteristics. Goal(s): To identify gadoxetate acid-enhanced MRI (Gd-EOB-MRI) features distinguishing hepatic inflammatory myofibroblastic tumor (IMT) from colorectal liver metastasis (CLM). Approach: This retrospective study included 10 IMT (0.7-7.1 cm) and 28 CLM (0.4-5.4 cm) patients who underwent Gd-EOB-MRI. Two reviewers assessed tumor characteristics. Results: Peripheral hypointense rim on T1WI, and arterial phase and/or portal venous phase, corresponding to the delayed enhanced rim on transitional phase, layered appearance on T2WI, and obscure hypointensity on hepatobiliary phase were commonly in IMTs, but rare in CLMs. Impact: The distinctive imaging features on Gd-EOB-DTPA MRI such as early target appearance and delayed enhanced rim and obscure hypointensity on Hepatobiliary phase, are helpful in differential diagnosis of IMT from colorectal liver metastasis.