兔慢性肾衰竭肾血流灌注的超声造影研究

Study on renal perfusion of chronic renal failure in rabbits with contrast-enhanced ultrasound

目的应用超声造影定量评价兔慢性肾衰竭不同阶段肾皮质血流灌注的变化。方法15只家兔注射阳离子化牛血清白蛋白（C—BSA）共8周，建立慢性肾衰竭模型。分别于注射C-BSA前、注射后2周、4周、6周、8周化验血肌酐、尿素氮；并于各时间点超声测量肾大小，之后对兔双肾进行超声造影，应用时间强度曲线定量分析肾皮质血流灌注。结果肾皮质血流灌注从注射C-BSA后4周起减低，表现为时间强度曲线参数中峰值强度减低（P〈0．05或P〈0．01），同时灌注速度和廓清速度均减低，表现为达峰时间和峰值强度减半时间延迟（P〈0．05或P〈0．01）。曲线下面积在2周、4周、6周时与注射前比较，差异无统计学意义（P〉0．05），8周时减小（P〈0．05或P〈0．01）。血肌酐、尿素氮自6周起明显升高（P〈0．05或P〈0．01）。肾体积从2周到6周增大，皮质增厚（P〈0．05或P〈0．01），8周时肾体积减小（P〈0．05），上述变化与病理表现相吻合。结论超声造影结合时间-强度曲线可定量分析慢性肾衰竭不同阶段肾皮质血流灌注情况；肾血流灌注的下降早于常规实验室检查指标的异常；慢性肾衰竭血流动力学的变化与病理变化密切相关。

Objective To assess renal perfusion of chronic renal failure（CRF） at different stages in rabbits by contrast-enhanced ultrasound. Methods Fifteen rabbits were injected cationic bovine serum albumin（C-BSA） intravenously for 8 weeks to establish CRF models. Serum creatinine（Scr） and blood urea nitrogen（BUN） were determined before injection and 2,4,6,8 weeks after C BSA injection respectively. The size of kidney was measured by two-dimensional ultrasound and contrast enhanced ultrasound was performed on bilateral kidneys at the same time points. Renal perfusion was analyzed quantitatively with the time intensity curve. Results Renal cortical perfusion reduced started at 4weeks after injection,manifested as the peak signal intensity（PSI） of the time-intensity curve parameters decreased（ P 〈0.05 or P 〈0.01 ）. The speeds of perfusion and clearance of kidney were slower,showed as the time to peak intensity（PIT） and the time to half of peak intensity（HPT） delayed （ P 〈0.05 or P〈0.01）. Compared with pre-injection,there were no differences in terms of the area under the curve（AUC） at 2,4 and 6 weeks after injection （all P〉 0.05）. And compared with pre-injection,2,4,6 weeks after injection, the AUC decreased at 8 weeks （ P 〈0.05 or P 〈0.01）. The level of Scr and BUN of rabbits had increased since 6 weeks after injection （ P〈 0.05 or P 〈0.01）. Two dimensional ultrasound showed the renal volume was enlarged and the cortex was thickened from 2 weeks to 6 weeks after injection （ P〈0.05 or P 〈0.01）. At 8 weeks after injection,the renal size had decreased as well （P 〈 0.05）. These ultrasound changes were in accordance with its pathological changes. Conclusions Contrast-enhanced ultrasound in combination with time intensity curve can quantitatively analyze the renal perfusion of CRF at different stages. The reduction of renal perfusion was earlier than the changes of routine laboratory indexes in rabbits with CRF. The haemodynamic changes of CRF rabbit were closely related with its pathological changes.