Quantitative Assessment Of Liver Fibrosis Based On Gd-EOB-DTPA Enhanced MRI

Part 1 Evaluation of liver fibrosis in CCl4 modeled New Zealand rabbits based on Gd-EOB-DTPA enhanced volume multi-flip angle T1 mapping and 18F-FDG PET/MRObjective:To investigate the feasibility of PET/MR as a quantitative tool to estimate liver fibrosis,T1 measurement using a multiple flip angle volume acquisition(VFA)of liver with Gd-EOB-DTPA-enhanced magnetic resonance imaging(MRI)sequence and 18 FFDG PET were carried out in this study.Methods:We prospectively included 56 male New Zealand rabbits in present study.Carbon tetrachloride(CCl4)was injected intraperitoneal in fibrotic group rabbits to induce different stages of liver fibrosis(total number=48),while the control group(n=8)received normal saline.The experimental scan was performed using an integrated PET/MR scanner(Signa PET/MR,GE Healthcare,WI,USA)with a special rabiit coil.All rabbits after modeling were subjected to 18F-FDG PET image acquisition(before Gd-EOB-DTPA injection)and 5 multi-turn angle T1 mapping scans(plain period and 5minutes/10min/15min/20 min after Gd-EOB-DTPA injection).The images were processed by GE post-processing workstation to obtain the SUVmean of the region of interest and the T1 decreasing rate of different injection durations(?T1-5min%,?T1-10min%,?T1-15min% and ?T1-20min%).The rabbits were put to death within 4 hours after the magnetic resonance examination to evaluate the pathological stage of liver fibrosis.Oneway ANOVA was performed on the imaging parameters of rabbits with different degrees of fibrosis by SPSS 25.0 software and multiple comparisons(LSD)were performed.A receiver operating characteristic analysis using the area under the receiver operating characteristic curve(AUC)was used to compare the diagnostic performance in predicting liver fibrosis between different parameters.P <0.05 was statistically significant.Results:A total of 34 rabbits had both pathological results and MRI information.The rabbits included in the analysis were divided into three groups according to the METAVIR grade of liver fibrosis: no fibrosis(F0),n = 10(29.4%);early fibrosis(F1-2),n = 16(47.1%);advanced fibrosis(F3-4),n = 8(23.5%).? T1-15min% and ? T1-20min%calculated by 15 minutes and 20 min VFA T1 maps after injection of Gd-EOB-DTPA have a good effect in the diagnosis of different degrees of liver fibrosis,and ?T1-20min% has better diagnostic effect.SUVmean has a better diagnostic effect on distinguishing between early fibrosis(F1-2)and severe fibrosis(F3-4),which is similar to ?T1-20min%.In terms of functional diagnosis,?T1-20min% has a significant diagnostic advantage over SUVmean.Conclusion:In the evaluation of liver fibrosis,the T1 mapping technique after Gd-EOBDTPA enhancement has a good diagnostic value in the delay of 15 min and 20 min,and ?T1-20min% is the best parameter.?T1-20min% and 18F-FDG PET SUVmean combined diagnosis of liver fibrosis has a good diagnostic value,and can be used as an important diagnostic basis for the assessment of liver fibrosis.Part 2 Quantitative assessment of hepatic fibrosis in chronic hepatitis B and C: T1 mapping on Gd-EOB-DTPA-enhanced liver magnetic resonance imaging Objective:T1 measurement of the liver using a Look-Locker inversion recovery sequence with Gd-EOB-DTPA-enhanced magnetic resonance imaging(MRI)is a newly emerging noninvasive method for assessing liver fibrosis.We investigated its feasibility as a quantitative tool to estimate liver fibrosis,and compared it with using measurement of the reduction rate of T1 relaxation time(RE).Methods:We prospectively included 109 patients with CHB or CHC who underwent a3.0-Tesla MRI examination,including T1-weighted and Look-Locker sequencesfor T1 mapping.Hepatocyte fractions(He F)andrelaxation time reduction rate(RE)were measured forstaging liver fibrosis.A receiver operating characteristicanalysis using the area under the receiver operating characteristic curve(AUC)was used to compare thediagnostic performance in predicting liver fibrosis between He F and RE.Results:A total of 73 patients had both pathological results and MRI information.The number of patients in each fibrosisstage was evaluated semiquantitatively according to the METAVIR scoring system: F0,n = 23(31.5%);F1,n = 19(26.0%);F2,n = 13(17.8%);F3,n = 6(8.2%),and F4,n =12(16.4%).He F by EOB enhancement imaging wassignificantly correlated with fibrosis stage(r =-0.81,P <0.05).AUC values for diagnosis of any(? F1),significant(? F2)or advanced(? F3)fibrosis,and cirrhosis(F4)using He F were 0.84(0.73-0.91),0.89(0.80-0.95),0.96(0.88-0.99),and 0.96(0.88-0.99),respectively.He F measurement was more accurate thanuse of RE in establishing liver fibrosis staging,suggesting that calculation of He F is a superior noninvasive liverfibrosis staging method.Conclusion:A T1 mapping-based He F method is an efficient diagnostic tool for the staging of liver fibrosis.