Department of Radiology, Mayo Clinic, Rochester, MN, United States of America.
Mayo Clinic Graduate School of Biomedical Sciences, Rochester, United States of America.
Phys Med Biol. 2022 Nov 11;67(22). doi: 10.1088/1361-6560/ac9c3f.
Measuring waves induced with acoustic radiation force (ARF) in arteries has been studied over the last decade. To date, it remains a challenge to quantitatively assess the local arterial biomechanical properties. The cylindrical shape and waveguide behavior of waves propagating in the arterial wall pose complexities to determining the mechanical properties of the artery.. In this paper, an artery-mimicking tube in water is examined utilizing three-dimensional measurements. The cross-section of the tube is measured while a transducer is translated over 41 different positions along the length of the tube. Motion in the radial direction is calculated using two components of motion which are measured from the two orthogonal views of the cross-section. This enables more accurate estimation of motion along the circumference of tube.. The results provide more information to categorize the motion in tube wall into two types of responses: a transient response and a steady state response. The transient response is caused by ARF application and the waves travel along the length of the tube for a relatively short period of time. This corresponds to the axial and circumferential propagating waves. The two circumferential waves travel along the circumference of tube in CW (clockwise) and CCW (counter-clockwise) direction and result in a standing wave. By using a directional filter, the two waves were successfully separated, and their propagation was more clearly visualized. As a steady state response, a circumferential mode is generated showing a symmetric motion (i.e. the proximal and distal walls move in the opposite direction) following the transient response.This study provides a more comprehensive understanding of the waves produced in an artery-mimicking tube with ARF application, which will provide opportunities for improving measurement of arterial mechanical properties.
在过去的十年中,人们一直在研究利用声辐射力(ARF)测量动脉中的波动。迄今为止,定量评估局部动脉生物力学特性仍然是一个挑战。波在动脉壁中传播的圆柱形状和波导行为给确定动脉的机械特性带来了复杂性。在本文中,利用三维测量研究了水模仿管中的动脉。当换能器沿管长移动 41 个不同位置时,测量管的横截面。径向运动是通过从横截面的两个正交视图测量的两个运动分量来计算的。这使得能够更准确地估计管圆周上的运动。结果提供了更多信息,将管壁中的运动分为两种类型的响应:瞬态响应和稳态响应。瞬态响应是由 ARF 应用引起的,波沿管的长度传播相对较短的时间。这对应于轴向和周向传播的波。两个周向波以 CW(顺时针)和 CCW(逆时针)方向沿管的圆周传播,并产生驻波。通过使用定向滤波器,成功地分离了这两个波,并更清楚地可视化了它们的传播。作为稳态响应,在瞬态响应之后产生一个周向模式,显示出对称的运动(即近端壁和远端壁沿相反方向移动)。这项研究提供了对 ARF 应用于动脉模拟管中产生的波的更全面的理解,这将为改进动脉机械特性的测量提供机会。