Venugopal Prem, Malcevic Ivan, Pastouchenko Nikolai, Seeley Charles E, Zhang Xuefeng, DeMarco J Kevin, Foo Thomas K
Annu Int Conf IEEE Eng Med Biol Soc. 2020 Jul;2020:2658-2661. doi: 10.1109/EMBC44109.2020.9175422.
The sound generated by diseased carotid arteries was investigated through computational means using three-dimensional, idealized, stenosed carotid bifurcation models. Stenosis levels of 50% and 70% with axi-symmetric and asymmetric stenosis shapes were considered. The hemodynamic flow field was obtained by solving the incompressible, Navier-Stokes equations. The resulting pressure fluctuations at the vessel walls were then used as input for a linearized wave equation for the propagation of vibrations through the modeled surrounding tissue. As observed in prior studies, the sound spectra obtained at the tissue surface indicate a 'break frequency', i.e. a frequency beyond which there is a drop-off in sound spectra intensity. This frequency was found to scale with stenosis diameter and average velocity at the stenosis throat, provided the stenosis shape remained the same. This has important implications on past attempts to estimate stenosis diameter from the break frequency.
通过使用三维理想化的颈动脉狭窄分叉模型，以计算方式研究了病变颈动脉产生的声音。考虑了50%和70%狭窄水平的轴对称和非对称狭窄形状。通过求解不可压缩的纳维-斯托克斯方程获得血流动力学流场。然后将血管壁上产生的压力波动用作线性化波动方程的输入，用于模拟振动在周围组织中的传播。如先前研究中所观察到的，在组织表面获得的声谱表明存在一个“截止频率”，即超过该频率后声谱强度会下降。发现该频率与狭窄直径和狭窄喉部的平均速度成比例，前提是狭窄形状保持不变。这对过去从截止频率估计狭窄直径的尝试具有重要意义。
