超声造影评价兔肾皮质血流灌注

摘要

Objective To explore the value of the ultrasound contrast agent in conjunction with advanced contrast imaging techniques in the evaluation of the renal cortical perfusion. Methods The animal model was established with ligating renal artery to cause the renal cortical perfusion decrease of rabbits. Real-time harmonic gray scale imaging was performed to visualize the contrast enhancement of the renal cortex. After bolus injection of contrast agent SonoVue, dynamic image was observed and recorded during the first three minutes. According to the time-intensity curve (TIC), accelerating time (AT),Peak intensity (A), time to half of peak intensity (T), difference between peak and base (PBD), slope rate of the curve (β) and the product of A and β (A·β) were obtained before and after the renal artery operation. The t test and correlation analysis was used to examine the above parameters. Results Before the renal artery operation, renal cortex enhanced rapidly and obviously, the way of the enhancement was renal artery-cortex-pyramids. After ligation of renal artery, AT prolonged evidently (P<0.001), A decreased obviously (P<0.001), T obviously shortened (P<0.001), PBD decreased markedly (P<0.001), while the decline of βinduced (P<0.002) and A·βobvious dropped(P<0.001). AT, BPD and A·βcorrelated with stenosis level of renal artery. Compared with 31%－69% group, AT prolonged evidently (P<0.001). A decreased obviously (P<0.029), PBD decreased obviously (P<0.001), A·β was dropped markedly (P<0.02) in 70%-93% stenosis group. Conclusions Contrast agent combining with developed contrast specific imaging is able to detect changes of renal cortical microcirculation sensitively with the help of analysis of TIC.%目的 探讨超声造影评价兔肾皮质血流灌注状态的价值.方法 通过结扎肾动脉建立不同程度家兔肾皮质血流减少的模型.经耳缘静脉团注SonoVue(0.05 ml/kg体质量)进行肾灌注超声造影,观察并采集注射造影剂后0～3 min的动态图像,通过时间-强度曲线(TIC)软件分别计算肾动脉结扎前后肾皮质TIC的加速时间(AT)、峰值背向散射强度(A)、峰值减半时间(T)、峰值基础视频强度差(PBD)、TIC斜率(β)以及A·β值,并对以上指标进行t检验及相关分析. 结果 实时观察发现肾动脉结扎前,肾皮质表现为快速明显强化,增强顺序为各级肾动脉-皮质-锥体.结扎后AT明显延长(P<0.001),A显著减小(P<0.001), T明显缩短(P<0.001), PBD明显减低(P<0.001),β明显下降(P<0.002), A·β值显著降低(P<0.001).肾动脉狭窄程度与AT、PBD及A·β呈明显的相关;肾动脉狭窄率在31%～69%之间组与70%～93%之间组比较,后者较前者AT延长(P<0.001),A减小(P<0.029), PBD减低(P<0.001), A·β值降低(P<0.02). 结论超声造影剂和造影专用成像技术可灵敏地反映肾皮质微小血管的血流变化,在评价肾皮质的血流灌注状态方面有很高的应用价值.