| ObjectivesTransplant renal artery stenosis (TRAS) is one of the relatively frequentcomplication after transplantation, TRAS can cause intractable hypertension,deterioration of renal function and graft failure. Early, accurate diagnosis of TRAScould reverse the pathogenetic condition. But the hypertension and deterioration ofthe transplant kidney can be caused by many factors, among these factor, TRAS isusually the cause. So, to search a accurate, convenient method to detect and diagnoseTRAS is very important. Duplex-Doppler seems to be the ideal screening, but it hasmissed diagnosis. Computed tomography (CT) and Magnetic resonance imaging(MRI) can provide a three-dimensional reconstruction of vessels, but still requiresadministration of intravenous contrast that have nephrotoxicity. The gold standard fordiagnosing stenosis still remains renal angiography, but the expensive of theexamnation, complication of the operation and nephrotoxicity and hypersensitivityreactions of the intravenous contrast restrict it's clinical application. Therefore, thistest applies enhanced ultrasound and acoustic densitometry technique to study thefeasibility of diagnosing transplant renal artery stenosis, meanwhile, to compare theblood perfusion parameter before TRAS with the parameter after TRAS, in order tofind more objective and sensitive index of detection and provide valuable information for the early diagnosis of TRAS after renal transplantation.Materials and Methods1. Animal Experiment1). Establishment of the animal models. Six male dogs(between 10 to 15 kgbody weight) were divided into 3 groups at random, tow dogs each group. Theyunderwent renal allograft transplantation with unilateral native kidney nephrectomy.The donor renal was located in the right iliac fossa mutually. To constrict of theexternal diameter of the renal artery to produce renal artery stenosis of differentextent, 35% slight grade stenosis, 55% medial grade stenosis and 85% severe gradestenosis.2). Equipment and contrast agent. The equipment used was PhilipsIU22color Doppler ultrasound with C5—2 (frequency 2～5MHz) and L9—3 (frequency3～9MHz) transducer. The contrast agent was "Quanfuxian" that provided byNangFang hospital.3). The examination methods. The contrast ultrasound was performed in 4hours before TRAS. It include the main renal artery contrast ultrasound and renalparenchyma contrast ultrasound. The main renal artery contrast ultrasound: the dogwas taken to dorsal decubitus, it's abdominal cavity was opened, the transplant renalwas exposed outside the peritoneum. A water sac was taken to above the main renalartery. The routine ultraphonic examination was performed, then when maximumbipolar length of the main renal artery was obtained, fixuped probe and startupedcontrast ultrasound condition. Intravenous bolus injection of contrast agent, followedby immediate flushing with 5ml saline. The dosage of contrast agent was0.3ml/every time. The dosage of contrast agent was 0.3ml every time. Then,obtained the maximum bipolar length of transplanted kidney, contrast ultrasound wasperformed again, meanwhile, to keep the Equipment's setup in the same. All the courses of contrast were recorded and stored in VCD disk for later analysis. Toanalyze the saved images with AD software after the examination, the time-intensitycurve was delineate automatically. Some parameters related to blood flow such asbase-to-peak ascending slope (A), peak intensity (PI) and the area under thecurve(AUC) were acquired.4). Statistical analysis. Data were expressed as mean±standard deviation.SPSS 10.0 software was used to analyze the date. The means comparison of eachparameter above mentioned among normal group, slight grade stenosis, medial gradestenosis and severe grade stenosis were evaluated statistically by repeatedmeasurement ANOVA and Multiple comparison between means (LSD). The P valuebelow 0.05 was considered statistically significant.2,Clinical research1). Patients. Ten cases who were suspected clinically to suffer from TRASwere examined with contrast ultrasound, eight patients of TRAS was diagnosedfinally by DSA. Contrast ultrasound was performed on 20 patients with normal TKalso. The results of TRAS were compared with those of normal TK.2). Equipment and contrast agent. The equipment used was Acuson 512with 4C1 (frequency1.0～4.0MHz) and 8L15 (frequency8～15MHz) transducer. Thecontrast agent was "Sono Vue" that produced by BRACCO corporation.3). Examination methods. (1) Routine ultraphonic examination. To observethe information of gray-scale mode and CDFI, such as size, morphous, the bloodflow of the reanl artery and so on. (2) Contrast ultrasound: To observe the main renalartery and the Transplant kidney's parenchyma respectively. Intravenous bolusinjection of contrast agent, followed by immediate flushing with 5 ml saline. Thedosage of contrast agent was 0.3m every time. Among the 10 cases, the results of 8patients who suffered from TRAS that confirmed by DSA were analyzed quantitatively. The time-intensity curve was delineate automatically. To calculate thetime enhancement (BT), time to peak intensity (PT), base-to-peak ascending slope(BPAS), half time of descent (HT), peak intensity (PI) and area under curve (AUC).4). Statistical analysis. Data of the 8 patients with TRAS (TRAS group) andthose of 20 patients with normal TK (control group) were expressed as mean±standard deviation. Statistical analysis is aided by SPSS10.0. The means comparisonof each parameter above mentioned between TRAS group and control group wereevaluated statistically by t test. A P value below 0.05 was considered statisticallysignificant.Results1,The 2D images of the normal dogs' transplant renal artery(TRA) wereenhanced after administration of contrast agents, and incomplete fullness were notseen, The renal parenchyma and cortex were greatly enhanced after injection. Thesehad uniform TICs with an early and steep increase of similar magnitude. To the dogswith TRAS, incomplete fullness was seen at the stenosis site of transplant renalartery. The renal parenchyma and cortex showed a less pronounced increase, thesegroups had TICs with slow-moving increase and low hump. There were statisticallysignificant differences between the mean values of these 4 groups. In TRAS group,base-to-peak ascending slope (A) was slower than that in normal group (P＜0.001),peak intensity (PI) and the area under and the curve (AUC) were lower than that innormal group (each P＜0.001).2,2 patients were exclude from suffering from TRAS by contrast ultrasound.The renal artery of 2 patiens was anfractous; 8 patients were confirmed by contrastultrasound, there were 5 cases' stenosis at the anastomosis, 1 cases' stenosis at theproximal to the anastomosis; 2 cases' stenosis at the distal to the anastomosis. Thegrading and localization of the stenosis confirms by contrast ultrasound coincidedwith the results confirmed by digital subtraction arteriography (DSA). We found statistically significant differences between all the values of the 2 groups. In stenoticgroup, BT (P＜0.005) and PT (P＜0.001) were longer than that in normal group; BPAS,HT, PI and AUC (each P＜0.001) were lower than that in normal group.Conclusions1. The neotype contrast enhanced ultrasound technique: pulse inversionharmonic contrast imaging (PIHCI) could significantly enhance the grey scaleimaging of the canine transplant renal arteries and renal parenchyma, we can identifythe stenosis from the incompelet fillness direct-viewing. It can also provide directand complete scenery of the perfusion by acoustic densitometry analysis, contrastultrasound has a good prospect in diagnosis of TRAS.2. Concerning the clinical research, contrast enhanced ultrasound can redeemthe deficient of CDFI, observer the main renal ateray distinctly, the results identifiedby contrast enhanced ultrasound were in reasonable to agreement with DAS;Meanwhile the statistically significant differences between the values of nomalgroup and TRAS group, suggest that contrast ultrasonography could detect thepresence of TRAS, and contrast ultrasonography can be use as an accurate methed todiagnose TRAS. |
PDF Full Text Request