Cloutier G, Allard L, Durand L G
Laboratoire de Génie Biomédical, Institut de Recherches Cliniques de Montréal, Québec, Canada.
Ultrasound Med Biol. 1995;21(1):59-70. doi: 10.1016/0301-5629(94)00093-x.
The main objective of the present work was to investigate, under pulsatile flow, the patterns of variation of the Doppler power backscattered by blood and Sephadex particles upstream and downstream of concentric and eccentric stenoses ranging from 47% to 91% area reduction. Doppler measurements were performed at 5 diameters upstream and 5, 10, 15 and 20 diameters downstream of the constriction. For the concentric 75% and 85%, and the eccentric 79% and 91% area reduction stenoses, a progressive increase of the power backscattered by red cell suspensions at 40% hematocrit was measured downstream of the narrowing. The maximal power usually occurred around 10 diameters after the stenosis and dropped further downstream. In addition to the increase in the power, a cyclic variation of the backscattered intensity was observed within the flow cycle. For the concentric 52% and eccentric 47% area reduction stenoses, no variation of the Doppler power was measured during flow acceleration and deceleration for all recording sites. A coefficient of correlation of 0.82 was measured between the percentage of area reduction and the ratio of the Doppler mean power at 10 diameters downstream to that at 5 diameters upstream of the stenoses. Using Sephadex particles at low concentration, no increase of the Doppler power was found downstream of the 85% and 91% area reduction stenoses. The possible link between the intensity of turbulence and the power backscattered by blood is discussed along with the influence of the correlation between the scattering particles, under turbulent flow.
本研究的主要目的是在脉动流条件下，研究面积减少47%至91%的同心和偏心狭窄上下游血液和葡聚糖颗粒反向散射的多普勒功率变化模式。在狭窄处上游5个管径处以及下游5、10、15和20个管径处进行多普勒测量。对于同心75%和85%、偏心79%和91%面积减少的狭窄，在狭窄下游测量到血细胞比容为40%的红细胞悬液反向散射功率逐渐增加。最大功率通常出现在狭窄后约10个管径处，并在更下游处进一步下降。除了功率增加外，在流动周期内还观察到反向散射强度的周期性变化。对于同心52%和偏心47%面积减少的狭窄，在所有记录部位，在流动加速和减速期间均未测量到多普勒功率的变化。测量到狭窄面积减少百分比与狭窄下游10个管径处的多普勒平均功率与上游5个管径处的多普勒平均功率之比之间的相关系数为?。使用低浓度的葡聚糖颗粒，在面积减少85%和91%的狭窄下游未发现多普勒功率增加。讨论了湍流强度与血液反向散射功率之间的可能联系以及湍流条件下散射颗粒之间相关性的影响。 （注：原文中“系数为0.82”后的表述好像不完整，根据语境添加了“?”）
