Quantitative Evaluation of Renal Cortex Perfusion using Contrast-enhanced Ultrasound Imaging Parameters in Renal Ischemia-reperfusion Injury in Rabbits

Background: Contrast-enhanced ultrasound (CEUS) can be used as a noninvasive and quantitative diagnostic method to judge the progression of renal ischemia-reperfusion injury. The aim of this study was to evaluate the blood perfusion of renal cortex during ischemia-reperfusion (I/R) injury by quantitative contrast-enhanced ultrasound (CEUS) parameters.Materials: In this experiment, 24 rabbits were randomly divided into following four groups (N=6): sham-operation group, 24-h post-operation of ischemia-reperfusion injury group (24-h I/R), 3-d post-operation of I/R injury group (3-d I/R) and 5-d post-operation of I/R injury group (5-d I/R). The I/R model was surgically established. CEUS was performed via a GE LOGIQ 9 ultrasound machine, and a time-intensity curve (TIC) in the renal cortex was generated for each group. All quantitative CEUS parameters were derived from TIC and included the following: the curve's peak ascending slope (wash-in slope [WIS]),area under the curve (AUC), time-to-peak (TTP), change in perfusion peak intensity (A), and arrival time (AT), Subsequently, we analyzed the changes in these parameters, as well as the correlation between changes in CEUS parameters and pathological parameters.Results: The values of AT, TTP, and WIS of all I/R groups significantly differed from the sham-operation group (P 0.05). The AT and TTP values peaked at 3 d after I/R surgery, which correlated with the most significant pathological changes at the same time point.Conclusions: Among the quantitative CEUS parameters, AT, TTP, and WIS were found to be sensitive indicators reflecting blood perfusion in renal microcirculation. Hence, these parameters may be useful for dynamically monitoring the severity of tissue damage at the early stage of I/R injury. Collectively, our findings provide compelling evidence for further clinical application of quantitative CEUS analysis.