Preliminary Study Of The Acoustic Radiation Force Impulse Imaging Technology In The Monitoring Of Transplant Kidney Elasticity Changes

Objective1. To investigate the application value of ARFI (Acoustic Radiation Force Impulse) technique in monitoring the elastic change of renal allograft.2. To assess the correlation between renal function alteration and renal allograft postoperative complications by using of ARFI to measure the transplanted kidney elasticity and to obtain the best threshold of ARFI value (Vs) when the renal function was abnormal so as to provide a new clinical observation index.Materials and Method53cases of renal transplantation examed by a Siemens ultrasonic apparatus. From November2010to March2012.A total of149ultrasonic inspections and ARFI value(Vs) measurements have been done3and7days after surgery and when decreased urine output and fever existed.9cases were executed renal graft biopsy. Exclusion standard:ascites, transplant hydronephrosis, peritransplant fluid collection. The upper renal artery embolization occurred in a special case who had a double renal transplant and this case was not included in the statistical analysis.The Siemens ACUSONS2000ultrasound imaging system equipped with ARFI imaging technology software was adopted.4C1 convex array probe with2.0-4.0MHz frequency was selected. We chose renal cortex, renal medulla and renal collecting system close to the abdominal wall side as the regions of interest, directing acoustic beam perpendicular to the kidney surface. Every inspected part was tested and recorded three times and was taken average. Index of the renal function and urinary volume was recorded the next day.RESULTS(1) Between the Vs of renal cortex, renal medulla and Serum creatinine values, there was a negative correlation; while the situation was opposite when it relates to the collection system.(2) Between the Vs of renal cortex and interlobar arterial resistance index, there was a negative correlation;the situation was on the contrary when the collection system was tested; when it relates to the renal medulla, there is no significant correlation.(3) In the serum creatinine normal group, renal parenchyma’s Vs were higher than that in the serum creatinine increased group, while the Vs of collection system of both groups was not statistically different.(4) In the rejection response group, the Vs of renal parenchyma was lower than that in ischemical reperfusion injury group, while the Vs of collection system of both groups was not statistically different.(5) The critical value of Vs in renal cortex, medulla and collection system is2.76m/s,2.33m/s and0.65m/s respectively to distinguish the renal function is normal or not.Conclusion1. ARFI could be quantified to reflect the elasticity of transplanted kidney and a decreased Vs suggested abnormal renal function and increased elasticity.2. ARFI may be important in identification of renal dysfunction caused by acute renal rejection or ischemical reperfusion injury.3. In monitoring the dysfunction of transplanted kidney, ARFI could be more sensitive than hemodynamic parameters and may be taken as a new indicator for the transplanted kidney...