A Comparative Analysis Of Magnetic Resonance Elastography With Transient Elastography And Diffusion Weighted Imaging In The Diagnosis Of Liver Fibrosis

Part 1 A preliminary study of magnetic resonance elastography in normalliver at 3.0 TObjectives The purpose of this study was to evaluate the application and repeatability of magnetic resonance elastography in normal liver at 3.0 T,and the relationship between the liver stiffness and age,sex,BMI.Methods Nineteen healthy volunteers(8 male and 11 female;mean age 40.8±14.3 years,range 20~71 years;mean BMI 22.4±2.6 kg/m2,range 19.5~28.7 kg/m2)were enrolled in this prospective study.Each volunteer underwent two MRE(Soochow Chuangbo Ltd,Philips Ingenia 3.0T MRI)examinations on the day of empty stomach,the interval of two scanning was at least 5 minutes,both the scanning parameters(60Hz,50%)and the level were the same.The liver stiffness measurements were obtained by two independent raters.The liver stiffness differences were calculated between two raters and sessions.Otherwise,the correlation between the liver stiffness values and the age,BMI and the difference among age,BMI,gender groups were analyzed using statistical methods.Results The intraclass correlation coefficient(ICC)was calculated to assess interrater agreement and intersession agreement.Both the ICCs of interrater agreement and intersession agreement were excellent at 0.907,0.886 and 0.708,0.789,.The two mean liver stiffness values were2.86±0.30 k Pa and 2.84±0.31 k Pa for healthy subjects.There was no significant correlation between the liver stiffness and the volunteers’ age or BMI two times(P=0.150,0.213;P=0.149,0.150).No significant difference was found among age,BMI or gender group two times(P=0.503,0.736;P=0.138,0.128;P=0.121,0.305).Conclusion MRE is a feasible quantitative technique that can be used to evaluate the stiffness of the liver,and the normal liver stiffness is not affected by age,sex and BMI.Part 2 A comparative analysis of MRE with transient elastography and diffusion weighted imaging in the diagnosis of liver fibrosis with chronichepatitis BObjectives The purpose of our study was to compare the utility of MR elastography(MRE)with Transient elastography(TE)and Diffusion weighted imaging(DWI)in characterizing fibrosis in Hepatitis B patients.Methods Twenty-four patients with chronic hepatitis B patients underwent abdominal TE,MRE(Soochow Chuangbo Ltd),and DWI(Philips Ingenia 3.0T MRI)within one week.The frequency of MRE was 60 Hz,and the amplitude was 50%.Otherwise,the b value of DWI was 800s/mm2.The ROIs were obtained by two independent raters in the MRE map and ADC map.Then all patients were divided into three groups: mild and non fibrosis(F0-1),significant fibrosis(F2-3)and cirrhosis(F4),according to the standard of TE.The difference of the MRE liver stiffness and ADC value among the three groups was analyzed using statistical methods.The overall predictive ability of MRE and DWI in assessment of liver fibrosis was analyzed by constructing receiver operating characteristic(ROC)curve.Results The ICCs of interrater agreement were both excellent at 0.963(95% CI: 0.913 to 0.984),0.910(95% CI:0.791~0.961).The significant difference of MRE LS was found among the three groups(F=61.690,P<0.001).For pairwise comparisons,the difference between the groups was significant.However,there was no significant difference of ADC value among the three groups(F=1.074,P=0.360).MRE showed excellent performance for characterizing significant fibrosis and cirrhosis,the AUCs were both above 0.9.While the AUCs of DWI were both less than 0.7.Conclusion MRE has an excellent performance for distinguishing the stages of liver fibrosis in patients with chronic hepatitis B,which is superior to DWI.