Characterization of high- and low-risk hepatocellular adenomas by magnetic resonance imaging in an animal model of glycogen storage disease type 1A

Purpose: Hepatocellular adenomas (HCA) are benign tumors whose most serious complications are hemorrhage and malignant transformation to hepatocellular carcinoma (HCC). Among various subtypes of HCA, β-catenin-activated (bHCA) are at greater risk of malignant transformation. Magnetic Resonance Imaging (MRI) is an important tool to differentiate benign and malignant hepatic lesions, and preclinical experimental approaches may help develop a method to identify MRI features associated with bHCA. HCA are associated to various pathologies, including Glycogen Storage Disease 1a (GSD1a). We have utilized a mouse model for GSD1a that develops HCA and HCC and analyzed these mice in order to distinguish low-risk from high-risk tumors. Methods: Animals were scanned by MRI using a hepato-specific contrast agent. Mice were sacrificed after MRI and lesions were classified using immunohistochemistry. Results: 45% of the animals developed focal lesions. MRI identified 4 different patterns after contrast administration: isointense, hyperintense, hypointense lesions and lesions with a peripheral contrast enhancement. After contrast administration, only bHCA and HCC were hypointense on T1-WI and mildly hyperintense T2-WI. Conclusions: We show that high-risk adenomas display MRI features clearly distinguishable from those exhibited by low-risk adenomas, indicating that MRI is a reliable method for early diagnosis and classification of HCA, necessary for correct patient management.