Cloutier G, Weng X, Roederer G O, Allard L, Tardif F, Beaulieu R
Laboratory of Biomedical Engineering, Institut de recherches cliniques de Montréal, Québec, Canada.
Ultrasound Med Biol. 1997;23(9):1383-93. doi: 10.1016/s0301-5629(97)00199-3.
The objectives of this study were to detect differences in the Doppler power backscattered by blood in vivo, and to identify factors affecting the backscattered power. The main hypothesis was that variations in the erythrocyte aggregation level between veins and arteries of normolipidemic and hyperlipidemic individuals can be detected with power Doppler ultrasound. Doppler measurements were performed at 5 MHz, with an Acuson 128 XP/10 system, over the carotid artery and jugular vein, external iliac artery and vein, common femoral artery and vein and popliteal artery and vein. Doppler signals were recorded at the center of each vessel to optimize the detection of erythrocyte aggregation, and processed off-line to obtain the backscattered power. The power of each recording was compensated for Doppler gain differences, tissue attenuation with depth and transmitted power variations occurring with pulse-repetition interval modifications. Results showed statistically stronger backscattered power in veins compared to arteries for the iliac, femoral and popliteal sites. In comparison with healthy subjects, stronger powers were observed in hyperlipidemic patients for the femoral and popliteal sites. Power differences were also found between peripheral measurements. On the other hand, no difference was observed between the power measured in the carotid artery and jugular vein for both groups of individuals. Multiple linear regression analyses were performed to identify factors affecting the backscattered power. Results showed a correlation (r) of 71.2% between the Doppler power in the femoral vein and the linear combination of two parameters: an erythrocyte aggregation index S10 measured with a laser scattering method, and the diameter of the vessel measured on B-mode images. Statistically significant linear correlation levels were also found between S10 and the Doppler power in various vessels. In conclusion, this study showed that power Doppler differences exist in vivo in large vessels between veins and arteries of normolipidemic and hyperlipidemic individuals. The Doppler power variations were also shown to be related to erythrocyte aggregation.
本研究的目的是检测体内血液反向散射的多普勒功率差异，并确定影响反向散射功率的因素。主要假设是，通过功率多普勒超声可以检测到正常血脂和高血脂个体的静脉和动脉之间红细胞聚集水平的差异。使用Acuson 128 XP/10系统在5 MHz频率下对颈动脉和颈静脉、髂外动脉和静脉、股总动脉和静脉以及腘动脉和静脉进行多普勒测量。在每个血管的中心记录多普勒信号，以优化红细胞聚集的检测，并进行离线处理以获得反向散射功率。对每次记录的功率进行补偿，以消除多普勒增益差异、组织随深度的衰减以及随着脉冲重复间隔改变而出现的发射功率变化。结果显示，在髂、股和腘部位，静脉的反向散射功率在统计学上比动脉更强。与健康受试者相比，高血脂患者在股和腘部位的功率更强。在外周测量之间也发现了功率差异。另一方面，两组个体的颈动脉和颈静脉测量功率之间没有差异。进行多元线性回归分析以确定影响反向散射功率的因素。结果显示，股静脉中的多普勒功率与两个参数的线性组合之间的相关性（r）为71.2%：一个是用激光散射法测量的红细胞聚集指数S10，另一个是在B模式图像上测量的血管直径。在S10与各种血管中的多普勒功率之间也发现了具有统计学意义的线性相关水平。总之，本研究表明，在正常血脂和高血脂个体的大血管中，静脉和动脉之间在体内存在功率多普勒差异。多普勒功率变化也与红细胞聚集有关。
