Intravoxel Incoherent Motion MR Imaging For Evaluation Of Donation After Cardiac Death Hepatic Ischemia Reperfusion Injury Regulating Liver Regeneration

Purpose: Using intravoxel incoherent motion(IVIM)magnetic resonance imaging to evaluate the changes of microcirculation perfusion and diffusion state during ischemia-reperfusion injury(IRI)after DCD liver transplantation,and explore the potential mechanism of IRI in regulating liver regeneration after liver transplantation.Methods and materials: 27 patients who underwent DCD liver transplantation in our hospital from September 2018 to September 2019 were prospectively collected.The gender,age,height,weight,basic liver disease,warm ischemia time and cold ischemia time were recorded.Follow-up examinations were performed at 3 week,3month and 6 month after liver transplantation,which were recorded as 3W,3M and6 M groups,respectively.At the same time,20 healthy volunteers with no underlying liver disease were collected and recorded as group N.Their gender,age,height and weight were recorded.All of the patients and volunteers underwent routine transverse T1 WI,T2WI and IVIM examinations of the liver.All of the patients tested the 1evels of red blood cell(RBC),hemoglobin(HGB),albumin(TP),prothrombin time(PT),alanine aminotransferase(ALT),and aspartate aminotransferase(AST),total bilirubin(TBIL),direct bilirubin(DBIL),indirect bilirubin(IBIL),total bile acid(TBA),alkaline phosphatase(ALP)and γ-glutamyl transpeptidase(γ-GGT).IVIM-derived parameters(Dslow,Dfast and PF)and liver volume of patients at different follow-up times were calculated by two radiologists and the liver regeneration rate(LRR)was calculated.The interclass correlation coefficient(ICC)was used to assess the inter-observer reliability of measurements.All data were performed the normality test.The one-way analysis of variance(ANOVA)or non-parametric Kruskal-Wallis test was used to evaluate whether there were statistical differences of IVIM parameters and LRR between different groups.The Spearman correlation analysis was used to evaluate the correlations between IVIM parameters,LRR,warm ischemia time,cold ischemia time and laboratory indicators.Receiver operating characteristic(ROC)curves for the various IVIM parameters were built to evaluate diagnostic performances.Results: Dslow,Dfast and PF values had good interobserver agreement with ICC of0.572 to 0.937.The differences in Dslow,Dfast,and PF values between the normal and patient groups were statistically significant overall(P<0.05).Dslow,Dfast,and PF values of patient groups were lower than the normal group,and increased gradually with the extend of follow-up time.Pairwise comparison results showed that,for Dslow values,there were significant differences between the N group and 3W and3 M groups(all P<0.05),but there were no significant differences between patient groups(P>0.05);for Dfast values,there were significant differences between the N group and 3W group and also among patient groups(all P<0.05);for PF values,there were significant differences between the N group and 3W groups,3W and 6M groups(all P<0.05).After liver transplantation,LRR showed a gradual decrease trend.The differences in LRR among patient groups were statistically significant overall(P<0.01),and pairwise comparisons showed statistically significant difference between 3W and 6M groups(P<0.05).Spearman correlation analysis results showed that there were significant negative correlations between Dslow values of 3W group,Dfast values of 6M group and LRR(r =-0.514,-0.714,all P<0.05).There were significant negative correlations between Dslow,Dfast and warm ischemia time(r =-0.762,-0.820),cold ischemia time(r =-0.729,-0.834),and PF values were negatively correlated with warm ischemia time(r =-0.471)(all P<0.05).There were significant negative correlations between Dfast values and ALT(r =-0.393),TBA(r =-0.385)and positive correlations between Dfast values and RBC(r = 0.625),HGB(r= 0.627).PF values were negatively correlated with PT(r =-0.389)(all P<0.05).ROC analysis showed that IVIM parameters were useful to evaluate the diagnostic efficacy of liver IRI after DCD liver transplantation,and there were no significant differences among IVIM parameters(P>0.05).Conclusion: IVIM can non-invasively,quantitatively characterize the liver microcirculation changes and IRI effects on liver regeneration after DCD liver transplantation.In the early postoperative period(3 weeks),IRI was heavier and liver volume increased significantly.As the follow-up time prolonged,the LRR gradually decreased and liver function gradually recovered.Up to 6 months after surgery,the liver microstructural changes have returned to normal levels.The results prompt that when the warm ischemia time within 30 minutes and cold ischemia time within 3hours,the more severe IRI is,the more obvious liver regeneration is.