Non-neoplastic Liver Lesions after Biliary Stenting: Gadoxetic Acid-enhanced MRI Findings and Clinical association

Abstract

Background:: Non-neoplastic liver lesions that show low signal intensity in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) after biliary stenting and require differentiation from liver metastases may be seen. Objective:: To evaluate the imaging findings and clinical association of non-neoplastic liver lesions showing hypointensity in the HBP of EOB-MRI after biliary stenting, and assess their differentiation from liver metastases. Methods:: This study included 30 patients who underwent EOB-MRI after biliary stenting for pancreatobiliary malignancies. Among these, 7 patients had pathologically diagnosed non-neoplastic liver lesions which appeared hypointense in the HBP, and were categorized into the non-neoplastic group. The remaining 23 patients without non-neoplastic liver lesions were included in the control group. Additionally, 29 patients with liver metastasis were included as the liver metastasis group. Clinical associations and imaging features were compared between the groups. Results:: A history of cholangitis and two or more biliary interventional procedures were significantly more frequently observed in the non-neoplastic group (p=0.002 and p=0.01, respectively) than in the control groups. Regarding the imaging findings, the liver to lesion signal intensity ratio in the HBP in the liver metastasis group was significantly higher than that in the non-neoplastic group (2.13 vs. 1.53, p=0.002). Additionally, liver metastases were visualized significantly more clearly on diffusion-weighted images (p=0.033) and HBP images (p<0.001) in comparison to non-neoplastic lesions. Conclusion:: Non-neoplastic liver lesions, probably due to biliary inflammation, may be observed in the HBP of EOB-MRI in patients after biliary stenting. These lesions may be associated with a history of cholangitis and repeated biliary intervention procedure, and need to be differentiated from liver metastases.