Hepatocellular carcinoma in patients with nonalcoholic fatty liver disease: Helical CT and MR imaging findings with clinical-pathologic comparison

Purpose: To retrospectively evaluate the clinical, pathologic, and helical computed tomographic ( CT) and magnetic resonance ( MR) imaging findings of hepatocellular carcinoma ( HCC) in patients with nonalcoholic fatty liver disease ( NAFLD). Materials and Methods: Institutional review board approval was obtained for this study; the need for patient informed consent was waived. Clinical, pathologic, and imaging findings were retrospectively evaluated in 22 men ( mean age, 64.5 years) with HCC and NAFLD. Helical CT and MR images were reviewed for morphologic features such as tumor size, margins, necrosis, and degree of enhancement. Results: Obesity, diabetes, and hypertension were common findings and were observed in 12 ( 55%), 14 ( 64%), and 13 ( 59%) of the 22 patients, respectively. The serum alpha-fetoprotein level was elevated in eight patients ( 36%). All patients had pathologic evidence of NAFLD. HCC was well-differentiated in seven patients, moderately differentiated in 11, and poorly differentiated in four. Large tumors ( mean diameter, 8.4 cm) were depicted at CT and/or MR imaging in all patients. Twenty-one patients had a solitary or dominant mass. At imaging, tumor margins were well defined in 17 patients, with a smooth surface in 17, and there was evidence of a tumor capsule in 15. Necrosis was depicted in 16 patients. There was no evidence of calcifications, central scar, fat, or abdominal lymphadenopathy. CT was performed in 20 patients. HCC was hypoattenuating on unenhanced CT scans in 14 patients, heterogeneously hyperattenuating in the arterial phase in 20, and hypoattenuating in the portal phase in 14. MR imaging was performed in 16 patients. HCC was hyperintense compared with liver parenchyma at T2-weighted MR imaging in all 16 patients, hypointense at T1-weighted imaging in 14, heterogeneously hyperintense at arterial phase T1-weighted imaging in 16, and hypointense at portal phase T1-weighted imaging in 14. Conclusion: HCC in patients with NAFLD is more likely to manifest as a large solitary or dominant mass characterized by smooth and possibly encapsulated margins, necrosis, and hyper-vascularity. (c) RSNA, 2007.