The Value Of R2* Values In Diagnosing Hepatic Warm Ischemia-reperfusion Injury

Objective: By duplicating hepatic warm ischemia-reperfusion injury(WIRI)model in rabbits,combined with clinical laboratory examination indexes and pathology examination result,to investigate the value of 3.0T blood oxygen level dependent(BOLD)MRI R2* values in diagnosing hepatic warm ischemia-reperfusion injury.Providing a new method to early accurately diagnosis hepatic warm ischemia-reperfusion injury.Methods:1.Fifty healthy adult New Zealand white rabbits were randomly divided into five groups(n=8),by Pringle method establishing the model of hepatic WIRI after ischemia for 10,20,30,40 minutes and 6 hours of reperfusion,the remaining 10 rabbits in the normal control group without any surgery.2.All of the experimental rabbits were scanned by 3.0T MRI and BOLD MRI,T2* values were measured by considered radiologist and the R2* values were calculated.3.After MR examination and routine assays were performed for testing the levels of alanine aminotransferase(ALT),lactatedehydrogenase(LDH),aspartate aminotransferase(AST)in the ear vein blood serum.4.Kill the rabbits with air embolism and harvest them after performing the routine assays,cut into 1cm3 small pieces and put them in 10% formaldehyde solution fixed more than 24 hours,the conventional paraffin embedding,5?m serial section,then HE staining and observe the change of liver tissue morphology.5.Take cryopreserved liver tissue,test the contents of the total superoxide dismutase(SOD),malondialdehyde(MDA),myeloperoxidase(MPO)in liver tissue in strict accordance with the kit.6.Analysis of variance(ANOVA)was used to compare the differences in R2* value and the differences of R2* values between two groups were compared with Dunnett T3 test,the R2* values of stages were compared with Mann-Whitney U test,non-parameter Kruskal-Wallis test was used to compare the differences in clinical test index among groups.Correlation between R2* value and clinical test index,stages of HWIRI with non-parameter Spearman test were analyzed.ROC curve was conducted to evaluate R2* values for prediction of hepatic WIRI and its stage.Results:1.Mean R2* values of the normal control group and 10min(T10 group),20min(T20 group),30min(T30 group),40min(T40 group)hepatic WIRI groups were(105.96±10.09)Hz,(126.01±5.02)Hz,(127.40±8.75)Hz,(136.97±7.06)Hz,(183.44±7.66)Hz respectively.Mean R2* values increased during the progression of hepatic IRI progression,and were positively correlated with the stage of hepatic WIRI(r=0.878,P=0.000).There were significant differences of R2* values among the stages of HWIRI(F=133.25,P<0.05)and among all of groups(P<0.05).2.The differences of ALT,AST,LDH,total SOD,MDA and MPO among groups was statistically significant(P<0.05).3.R2* values and ALT,AST,LDH,MDA and MPO were significantly positively correlated(r>0.495,P<0.05),R2* and total SOD were significantly negatively correlated(r=-0.658,P=0.00).4.In microscopically,normal hepatic sinus and liver cells can be seen in the liver tissue of control group;mild edema of liver cells and a small amount of inflammatory cells infiltration in portal area and hepatic lobule can be seen in the liver tissue of T10 group and T20 group;In the liver tissue of T30 group and T40 group can see massive edema and deformed liver cells,a small amount of eosinophilic necrosis foci and point necrosis foci,a large number of inflammatory cells can be seen in the hepatic lobule and portal area.5.The differences of R2* values among S0 or greater,S1 or greater,S2 or greater and S3 or greater,S4 or greater was statistically significant(P<0.05).6.Predictor for S4 or greater is better than predictor for S1 or greater,S2 or greater and S3 or greater,the AUC were 1.000,0.967,0.893,0.955 respectively.The best diagnostic threshold were 159.05 Hz,115.00 Hz,132.00 Hz,133.35 Hz respectively.Conclusion: 1.Mean R2* values increased after hepatic WIRI,BOLD-MRI R2* values can diagnosis hepatic WIRI.2.BOLD-MRI R2* values can reflect the severity of hepatic WIRI,are sensitive and specific in diagnosing hepatic WIRI,and have help to diagnosis hepatic WIRI in further clinical medicine.