Abstract: Objective To explore the clinical efficacy of single,double and stretch index model under diffusion weighted imaging （DWI） of MRI in evaluating liver fibrosis in patients with chronic hepatitis B （CHB）.Methods 77 patients with CHB and 20 healthy persons were recruited in this study between February 2014 and September 2017. All patients received liver biopsies and individuals in both groups received MRI examination,and the parameters,e.g. ADCst as surface diffusion coefficient,Dt as real diffusion coefficient,Dp as false diffusion coefficient,f as perfusion related volume fraction,DDC as diffusion distribution index and α as water molecule diffusion heterogeneity index.Results The ADCst,Dt,f and DDC in patients with CHB were（0.899±0.080）×10^-3 mm²/s,（0.591±0.092）×10^-3 mm²/s,（32.374±7.472）×10^-3 mm²/s and（1.103±0.257）×10^-3 mm²/s,significantly lower than【（0.986±0.095）×10^-3 mm²/s,（0.704±0.073）×10^-3 mm²/s,（39.686±5.871）×10^-3 mm²/s and （1.394±0.243）×10^-3 mm²/s,P<0.05】 in healthy persons;there were significantly statistical differences as respect to ADCst,Dt,f and DDC in 25 patients without liver fibrosis,29 with significant liver fibrosis and 23 with liver cirrhosis （P<0.05）;the AUC of ADCst,Dt,f and DDC in diagnosing liver fibrosis were 0.841,0.934,0.770 and 0.926,respectively. Conclusion The application of double and stretch index models in diagnosing liver fibrosis in patients with CHB have a promising results,which might be validated in multicentral clinical trials.

Key words: Hepatitis B, Liver fibrosis, MRI, Double index model, Stretch index model, Diagnosis