Abstract: Objective To explore the value of MR spectroscopy (MRS) in detecting intrahepatic fat infiltration (FF) in the diagnosis of nonalcoholic fatty liver disease (NAFLD). Methods Between December 2016 to December 2019, 138 patients with NAFLD in our hospital received routine CT examination. All patients underwent MRS examination within 3 days after CT examination to obtain FF value. MRS spectrum lines of NAFLD patients with different degrees were analyzed, FF values of NAFLD patients with different degrees were compared, and the correlation between FF values and NAFLD severity and CT_liver/spleen was evaluated. Results 138 patients with NAFLD successfully completed MRS examination.The water peak and lip peak of MRS spectrum in all patients showed double peaks, and the other substances were close to the straight line;Among them, patients with mild and moderate NAFLD showed high anteropotential and low anteropotential, namely high water peak and low lip peak, while patients with severe NAFLD showed low anteropotential and high lip peak, namely low water peak and high lip peak.The FF value of patients with mild NAFLD was significantly lower than that of patients with moderate and severe NAFLD (P<0.05), and the FF value of patients with moderate NAFLD was significantly lower than that of patients with severe NAFLD (P<0.05).FF value was highly positively correlated with NAFLD severity (rank correlation coefficient r_S=0.838, P<0.001).FF value in NAFLD patients was negatively correlated with CT_liver/spleen (r=-0.920, P<0.001). Conclusion The detection of FF by MRS was of great significance to evaluate the severity of NAFLD and should be widely used in clinical practice.

Key words: Magnetic resonance spectroscopy, Intrahepatic fat infiltration, Nonalcoholic fatty liver disease