Abstract: Objective The aim of this study was to summarize magnetic resonance imaging feature of focal nodular hyperplasia (FNH) of liver. Methods 35 patients with FNH were encountered in in our hospital from January 2021 to June 2024, and all underwent MR scan and hepatectomy for removal of the tumors. Diagnosis was confirmed by surgical tissue examination pathologically. Results Of the 35 patients with FNH, 63 nodules were found by MRI, present as lobulated or quasi-circular, main solitary, located in right lobe, with diameters of 0.5-14.3 cm (mean 4.1±0.9)cm, and lesions were ≤3.0 cm in 41 and ＞3.0 cm in 22; MRI sequence showed equal or slightly low signals on T₁WI, while slightly high signals on T₂WI and DWI, without diffusion limitation; multi-phase dynamic enhancement scan showed a fast-in and slow-out enhancement mode; proportions of steatosis, local necrosis, pseudocapsule, no central scar, no obvious enhancement at arterial phase and low signals at hepatobiliary phase in nodules with diameter >3.0 cm were 77.3%,68.2%, 86.4%, 63.6%, 73.7% and 63.6%, all significantly higher than 31.7%, 24.4%, 38.1%, 29.3%, 46.3% and 26.9% (P＜0.05) in those with diameter ≤3.0 cm. Conclusion MRI feature of FNH of liver is typical and some special, which might help clinicians differentiate it from malignant tumors.

Key words: Focal nodular hyperplasia of liver, Magnetic resonance imaging, Feature, Diagnosis