Accurate evaluation of viscoelasticity of radial artery wall during flow-mediated dilation in ultrasound measurement

Abstract

In our previous study, the viscoelasticity of the radial artery wall was estimated to diagnose endothelial dysfunction using a high-frequency (22 MHz) ultrasound device. In the present study, we employed a commercial ultrasound device (7.5 MHz) and estimated the viscoelasticity using arterial pressure and diameter, both of which were measured at the same position. In a phantom experiment, the proposed method successfully estimated the elasticity and viscosity of the phantom with errors of 1.8 and 30.3%, respectively. In an in vivo measurement, the transient change in the viscoelasticity was measured for three healthy subjects during flow-mediated dilation (FMD). The proposed method revealed the softening of the arterial wall originating from the FMD reaction within 100 s after avascularization. These results indicate the high performance of the proposed method in evaluating vascular endothelial function just after avascularization, where the function is difficult to be estimated by a conventional FMD measurement.

Artery Wall Viscoelasticity: Measurement, Assessment, and Clinical Implications

“…A harmonic analysis was performed, and dynamic elastic moduli (E d ) were obtained for different frequencies. Sakai et al [29] measured the changes in luminal diameter and pressure simultaneously using B-mode US and tonometry for a silicone phantom and human radial artery. They estimated the transient change in viscoelasticity during a flowmediated dilation.…”

“…Although a highresolution (spatial accuracy of less than 1 μm) US measurement technique using the phased tracking method has been developed [28], its clinical application has not yet been fully established. Tonometry has been frequently used in previous in vivo experiments [26][27][28][29][30] for local pressure measurement, but arterial wall compression can affect the intramural pressure, wall motion, and smooth muscle activity [26]. Another limitation is related to the theory of using a thin-walled tube to compute the wall elasticity.…”

Accurate measurement of elasticity of the radial artery wall considering changes in cross-sectional shape of artery caused by pushing pressure applied by ultrasound probe

“…Sakai et al proposed a method for measuring the blood pressure waveform and the strain of the vessel wall at the same position by a correction determined from the delay between the pressure waveforms measured by two pressure sensors, where the ultrasound probe for the strain measurement was placed at the center of the two pressure sensors. 26,27) However, it was difficult to accurately determine the delay between the two pressure waveforms because it depends on the instantaneous pressure of the pressure waveforms.…”

Enhancement of reflection and backscattering components by plane wave imaging for estimation of surface roughness

“…It uses the ultrasound echo to observe how much the blood vessels dilate after avascularization induced by compression of the arm with a cuff. [21][22][23] Unfortunately, if a patient has undergone shunt surgery for dialysis or lymph node dissection for breast cancer, this test cannot be performed. Owing to this background, there is a need for technology that can diagnose arteriosclerosis early and safely.…”