Clinical Study Of Multiparameter Magnetic Resonance Imaging In The Evaluation Of Renal Transplantation

Chapter ⅠEvaluation of graft artery stenosis by non contrast enhanced magnetic resonance angiographyPurpose To evaluate image quality of non-contrast-enhanced magnetic resonance angiography(NCE-MRA),and compare transplant renal artery stenosis(TRAS)seen by non-contrast-enhanced MRA with the results of the digital subtraction angiography(DSA)as the gold standard.Materials and methods 330 patients receiving 369 non-contrast-enhanced MRA examinations from July 2014 to June 2017 were included.Thirty patients received at least two non-contrast-enhanced MRA examinations.Image quality was independently assessed by two radiologists,and the consistency between them was analyzed.Taking each non-contrast-enhanced MRA examination and each renal artery as the counting unit,the transplanted renal artery stenosis was evaluated and compared with the results of DSA.Results Good or excellent image quality was found in 95.4%(352/369)of examinations,and the consistency between the two radiologists was good(k=0.760).Twenty patients with DSA had 26 non-contrast-enhanced MRA examinations within a 2-month period.Of these,DSA showed that 19 transplanted renal arteries had TRAS,and two patient had a normal transplant renal artery(but in one case,the anastomotic external iliac artery was occluded).Non-contrast-enhanced MRA correctly detected 19 TRAS and nine normal arteries,giving 96.6%diagnostic accuracy on a per-artery basis.Conclusions Non-contrast-enhanced MRA demonstrates a good depiction of the transplanted renal artery and shows high consistency with DSA in cases where there was TRAS.Chapter ⅡThe clinical value of ASL/BOLD in evaluating renal allograft by comparative histopathological analysisObjective:This retrospective study was designed to assess the function and pathological changes of renal allografts using arterial spin labeling(ASL)and blood oxygen level-dependent(BOLD)imaging.Materials and methods:From June 2014 to September 2019,135 renal transplant patients were grouped according to renal function and pathological results,including normal group and insufficiency group,pathological negative group and positive group.Renal blood flow(RBF)and effective transverse relaxation rate(R2*)were calculated by comparing ASL and BOLD imaging.The correlation between BOLD/ASL parameters and clinical data were evaluated.Receiver operating characteristic(ROC)was used to evaluate the combined diagnostic performance of ASL,BOLD and eGFR.The prediction models were based on ASL and BOLD parameters using multivariate logistic analysis.Cox proportional hazards regression model was used to analyze the effects of gender,age,ASL and BOLD on the survival of renal transplant patients.Results:There were significant statistical differences in the correlation between renal transplantation time,eGFR,RBF and R2*(P<0.05).Compared with normal renal function group/negative pathology group,the RBF in renal insufficiency group/positive pathology group decreased significantly,and the R2*increased significantly(P<0.001);Multivariate logistic regression showed that the RBF increased,the risk of pathological positive was significantly reduced(P<0.001),and the risk of renal insufficiency was also significantly reduced(P<0.001);ROC curve shows that both ASL and BOLD can predict renal function impairment and pathological positive results,and the prediction effect of ASL is very good(AUC>0.85),and the prediction effect of bold is general(AUC>0.70).The AUC of combination BOLD and ASL is equivalent to ASL.Therefore,the combination with ASL can improve the diagnostic performance of BOLD;Cox regression showed that the increase of R2*accelerated the progression of renal insufficiency,and the increase of RBF delayed the progression of positive pathological injury.This study also found that the longer time of renal transplantation will lead to the more the loss of renal function and the greater the positive pathological injury.Conclusion:ASL and BOLD values were associated with renal function injury and renal allograft positive pathology.ASL and BOLD have good prospects for predicting renal allograft function and pathological changes.