Abstract: Objective The aim of this study was to investigate imaging feature of multi-slice spiral computed tomography (MSCT) and enhanced magnetic resonance imaging (MRI) in the differential diagnosis of focal nodular hyperplasia (FNH) of liver and hepatocellular carcinoma (HCC). Methods A total of 108 patients with intrahepatic space-occupying lesions (SOL) were encountered in our hospital between January 2016 and August 2024, and all underwent dual-source force 256-slice spiral CT and enhanced MAGNETOM Spectra 3.0 T MRI scans. Results Of 108 patients with SOL in our series, the histo-pathological examination proved FNH in 41 cases, with lesion diameter of (3.3±0.9)cm, and HCC in 67 cases, with diameter of (2.9±0.9)cm; MR arterial enhancement fractional (AEF) and lesion/liver AEF ratio in HCC were (67.7±7.6) and (1.4±0.2), both significantly higher than [(53.7±4.5) and (1.2±0.1), respectively, P＜0.05] in FNH; percentage of low signals on T1WI in HCC was 83.6%, much higher than 58.5%(P＜0.05), percentage of low signals on apparent diffusion coefficient (ADC) was 94.0%, much higher than 14.6%(P＜0.05), and percentage of fast in and fast out style of enhancement was 91.0%, much higher than 2.4%(P＜0.05) in FNH; relative ADC in HCC was (0.8±0.2), much lower than [(1.1±0.2), P＜0.05] in FNH. Conclusion Features of MSCT and enhanced MRI could help clinicians make differential diagnosis of FNH from HCC, which might be very important in clinical practice.

Key words: Hepatocellular carcinoma, Focal nodular hyperplasia, Multi-slice spiral computed tomography, Enhanced magnetic resonance imaging, Differential diagnosis