Quantitative analysis of contrast-enhanced ultrasonography in differentiating acute rejection from acute tubular necrosis of transplant kidney

Abstract

Objective To evaluate the value of quantitative analysis of contrast-enhanced ultrasonography （CEUS） in differentiating acute rejection （AR） from acute tubular necrosis （ATN） of transplant kidney.Methods Total of 67 kidney recipients were examined with conventional US and CEUS. Biopsies were performed in 37 patients, 26 patients were with AR, 11 with ATN, 30 patients as control group.The hemodynamie parameters （PSV and RI） were measured on infrarenal artery with conventional US,while CEUS quantitative analysis was performed on the cortex, pyramid and interlobar artery by time- intensity curve （TIC）.TIC parameters including rise time （RT）, time to peak （TTP）, mean transit time （mTT） were compared among three groups. In addition, the reproducibility of TIC parameters was evaluated.Results The RI in AR group was significantly higher than that in control group,but there were no significant differences of RI between AR and ATN groups.TIC parameters including RT,TTP were with high reproducibility （ICC〉0.75）.Compared to the other two groups, the RT and TTP of the pyramid, △RTm-c, and △TTPm-c were significantly longer in AR group, the receiver operating curves （ROC） analysis demonstrated that △RTm-c had the highest accuracy and RI had the lowest accuracy for detecting AR（areas under the curve were 0.786,0.756,0.749, 0.736 and 0.498, respectively）. High sensitivity and specificity（78.3% and 73.5% ,respectively） were shown when using 4.62 s as a cutoff point of ARTm-c to diagnose AR.Conclusions Quantitative analysis of CEUS could detected the changes of the microcirculation perfusion in kidney grafts with AR and ATN,which might be superior in the diagnosis of AR compared with conventional US. Key words: Ultrasonography; Microbubbles ; Kidney transplantation; Graft rejection; Kidney tubularnecrosis,acute