Abstract: Objective To evaluate the diagnostic value of FibroTouch^® by fat attenuation index（FAI） in patients with non-alcoholic fatty liver diseases（NAFLD）. Methods A total of 86 patients with NAFLD and 90 healthy persons were recruited in this study. NAFLD group was divided into mild,moderate and severe liver steatosis based on B-ultrasonography. Two independent sample t-test was used to compare body mass index （BMI）,FAI and liver stiffness were obtained by FibroTouch^® between NAFLD group and healthy control. One-way analysis of variance was used to compare above parameters among mild,moderate and severe liver steatosis. Pearson correlation was used to analyze the relationship between FAI and BMI or liver stiffness. Receiver operating characteristic（ROC） curves were plotted,and the areas under the curves（AUC） were calculated. The cut-off values were defined by maximizing the sum of sensitivity and specificity（maximum Youden index）. Results Between control group and NAFLD group,BMI were [（22.9±2.1） kg/m² and （27.8±3.4） kg/m²,P<0.001],FAI were [（215.1±16.3） db/m and （263.0±25.1） db/m,P<0.001],liver stiffness were [（5.1±1.1） Kpa and （8.8±5.7） Kpa,P<0.001];Among mild（n=43）,moderate（n=28）,severe（n=15） liver steatosis,FAI showed significant difference [（244.0±9.9） db/m,（273.8±9.7） db/m and（301.9±20.1） db/m,P<0.001];FAI showed positive correlation with BMI （r=0.741,P<0.001） and liver stiffness （r=0.442,P<0.001）;AUC of normal vs. mild,mild vs. moderate, and moderate vs. severe were（0.935,0.986,and 0.969,respectively,P<0.001）;The cut-off values for mild, moderate,and severe liver steatosis were 237 db/m（sensitivity 96.7%, specificity 86.4%）,259 db/m （se. 97.7%, sp. 92.9%）,and 286 db/m（ se. 96.4%,sp. 93.3%）,respectively. Conclusion FAI shows advantages in diagnosing NAFLD,and has a promising diagnostic potential for grading liver steatosis in patients with NAFLD.

Key words: Non-alcoholic fatty liver diseases, FibroTouch®, Fat attenuation index, Liver steatosis