对比超声定量评价肾髓质血流灌注

Quantification of renal medullary perfusion with contrast-enhanced ultrasound:an experi-mental study

目的定量评价多巴胺(DA)和去甲肾上腺素(NE)对肾脏髓质血流灌注的影响,探讨肾脏髓质内的血流灌注特征。方法分别在基础状态以及不同剂量DA和NE作用下,测量10只实验犬左肾动脉血流量,并进行对比超声(CEU)检查。CEU采用经静脉微泡连续输注法进行,评价肾皮质和髓质,以及外髓、中髓和内髓的平台声强度(A),造影剂再充填速率(β)和Aβ。结果3种剂量DA作用时,肾髓质血流灌注各参数(A值、β值和Aβ值)的变化与相应肾皮质血流灌注各参数的变化相似;各参数的肾皮质/肾髓质比值与静息状态时相应的各参数肾皮质/肾髓质比值之间无显著变化(P>0.05)。在不同剂量NE作用时,肾髓质血流灌注各参数与静息状态时比较无显著差异(P>0.05);各参数的肾皮质/肾髓质比值均较静息状态时明显减少(P<0.05),且剂量越大该比值越小(P<0.05)。在肾髓质内,血液流速显梯度分布,从外髓到内髓,血液流速逐步减慢(P<0.05);而血流容积从外髓到内髓无明显差异(P<0.05)。结论DA作用下肾髓质和肾皮质血流灌注的改变一致;而在NE作用下,肾髓质血流灌注无明显变化。在肾髓质内,血液流速呈梯度分布,从外髓到内髓,流速逐步减慢。

Objective To quantitatively evaluate the effects of dopamine (DA) and noradrenaline (NE) on renal medullary perfusion and the differences in perfusion in the outer and inner medulla using contrast-enhanced ultrasound.Methods and Results Contrast-enhanced ultrasound was performed in 10 dogs with simultaneous renal artery flow (RAF) measurement at the baseline level and during application of 3 different doses of DA and NE.During treatment with the 3 doses of DA,the changes of ultrasound-derived parameters (A,β and A*β) in the medulla were similar to the changes in the cortex.As compared with the baseline level,the ratios between the cortex and medulla exhibited no significant difference in A,β and A*β during DA treatment (P>0.05).No significant difference in ultrasound-derived medullar parameters was noted in dogs with NE treatment from the baseline level (P>0.05).However,a progressive decrease in the ratios of A,β and A*β between the cortex and medulla was noted during NE treatment in comparison with the baseline level (P<0.05).The velocity (β) and perfusion (A*β) of blood flow in the medulla decreased progressively from the outer medulla to the inner medulla at baseline (P<0.05),while the blood volume (A) remained unchanged (P<0.05).Conclusions The changes of blood flow in both the cortex and medulla are identical during DA treatment but different in the presence of NE.The progressive decrease in perfusion from the outer medulla to the inner medulla is attributed to the decrease in the velocity of blood flow.