Abstract: Objective The aim of this study was to investigate magnetic resonance imaging proton density fat fraction (MRI-PDFF) in predicting liver steatosis in patients with nonalcoholic fatty liver disease (NAFLD). Methods 96 patients with NAFLD and 55 healthy volunteers were enrolled in our hospital between December 2022 and December 2023, and all underwent MRI scan for MRI-PDFF measurement. Liver stiffness measurement (LSM) AND controlled attenuation parameter (CAP) were detected by transient elastography. Liver biopsy was performed in patients with NAFLD. Results MRI-PDFF, CAPand LSM in patients with NAFLD were (27.5±9.6)%,(297.2±35.2)dB/m and (10.3±2.3)kPa, all significantly higher than [(9.8±3.3)%, (251.7±14.4)dB/m and (5.1±1.3)kPa, respectively, P<0.05] in healthy persons; LSM,CAPand MRI-PDFF in 16 patients with histology-proven severe liver steatosis were (11.8±2.0)kPa, (341.1±32.2)dB/m and (37.3±8.3)%, all significantly higher than [(10.4±1.8)kPa, (284.0±12.7)dB/m and (25.1±3.4)%, respectively, P<0.05] in 29 patients with moderate liver steatosis or [(8.9±1.7)kPa, (263.5±7.7)dB/m and (14.4±3.2)%, respectively, P<0.05] in 51 patients with mild liver steatosis; ROC analysis showed that the AUC was 0.903, with sensitivity of 87.5% and specificity of 93.1%(P<0.05), when MRI-PDFF equal to or greater than 31.4% was set as the cut-off-value in predicting severe liver steatosis in patients with NAFLD. Conclusion Utility of MRI-PDFF could help clinicians for surveillance of liver steatosis in patients with NAFLD in clinical practice, especially for dynamic evaluation in process of intervention.

Key words: Nonalcoholic fatty liver disease, Liver steatosis, Magnetic resonance imaging proton density fat fraction, Diagnosis