Kaluzynski K, Lesniak B, Mikolajczyk K, Liepsch D
Institute for Precision and Biomedical Engineering, Warsaw University of Technology, Poland.
Technol Health Care. 1997 Jul;5(3):199-206.
In this study properties are concerned of ultrasonic Doppler spectra recorded distal to an irregularity localised in the internal carotid artery of a true-to-scale elastic model of a severely stenosed carotid bifurcation. Four models differing in irregularity were obtained by melting graded holes in the original wax cast, about 5-7 mm distal to the bifurcation. Velocity data were collected using an HP Sonos 2500 ultrasonograph working in pulsed Doppler mode. The observed effect of the irregularity with respect to the smooth wall model consisted in: (1) presence of a reduced flow zone 15 mm distal to the severe irregularity situated at the outer wall of the model in the ICA branch; (2) presence of a recirculation zone 15 mm distal to the severe irregularity situated at the inner wall of this model; (3) negative values of the measure of symmetry of the Doppler spectrum and (4) decreased values of relative width of Doppler spectra obtained 25 mm distal to the bifurcation in models with severe irregularity. The alterations of flow distribution and Doppler spectra depend on the geometry of the model under investigation and this study provides an indication as to what phenomena can happen in a model of stenosed carotid bifurcation with irregular lesion surface and how these phenomena may affect the ultrasonic Doppler spectra. Such information could be used in the evaluation of the risk of cerebral embolism.
在本研究中，关注的是在严重狭窄的颈动脉分叉处真实比例弹性模型的颈内动脉中，位于不规则处远端记录的超声多普勒频谱的特性。通过在原始蜡铸模型中距分叉约5 - 7毫米处熔化渐变孔，获得了四种具有不同不规则性的模型。使用工作在脉冲多普勒模式下的惠普Sonos 2500超声仪收集速度数据。相对于光滑壁模型，观察到的不规则性的影响包括：（1）在颈内动脉分支模型外壁的严重不规则处远端15毫米处存在血流减少区；（2）在该模型内壁的严重不规则处远端15毫米处存在再循环区；（3）多普勒频谱对称性测量值为负值；（4）在具有严重不规则性的模型中，在分叉远端25毫米处获得的多普勒频谱相对宽度值降低。血流分布和多普勒频谱的改变取决于所研究模型的几何形状，本研究表明在具有不规则病变表面的狭窄颈动脉分叉模型中可能发生哪些现象，以及这些现象如何影响超声多普勒频谱。此类信息可用于评估脑栓塞风险。
