Improvement in Accuracy of Ultrasonic Measurement of Transient Change in Viscoelasticity of Radial Arterial Wall Due to Flow-Mediated Dilation by Adaptive Low-Pass Filtering

2012 ◽  
Vol 51 (7S) ◽  
pp. 07GF14 ◽  
Author(s):  
Kazuki Ikeshita ◽  
Hideyuki Hasegawa ◽  
Hiroshi Kanai
Keyword(s):  
Arterial Wall ◽  
Ultrasonic Measurement ◽  
Flow Mediated Dilation ◽  
Transient Change ◽  
Low Pass

In Vivo Measurements of Change in Viscoelasticity of Arterial Wall During the Flow-Mediated Dilation

2009 ◽  
Author(s):  
Hiroshi Kanai ◽  
Hideyuki Hasegawa ◽  
Kazuki Ikeshita
Keyword(s):  
Elastic Modulus ◽  
Endothelial Function ◽  
Hysteresis Loop ◽  
Arterial Wall ◽  
Radial Strain ◽  
Least Square ◽  
Flow Mediated Dilation ◽  
Transient Change ◽  
In Vivo Measurements

The present paper introduces in vivo measurements of viscoelasticity of arterial wall developed in our laboratory. The endothelial dysfunction is considered to be an earliest stage of atherosclerosis. Moreover, it was reported that the smooth muscle, which constructs the media of the artery, changes its characteristics due to atherosclerosis. Therefore, it is essential to develop an in vivo measurement method to assess the regional endothelial function and mechanical property (viscoelasticity) of the arterial wall. To evaluate the endothelial function, there is a conventional technique for measuring the transient change in the diameter of the brachial artery caused by flow mediated dilation (FMD) after the release of avascularization. However, this method does not directly evaluate the viscoelasticity of the intima-media region of the arterial wall. In the present paper, therefore, we proposed a method for simultaneous measurement of waveforms of the radial strain and blood pressure at the radial artery, and we developed its measurement system. From in vivo experiments, the viscoelasticity parameters of the arterial wall were estimated from the measured stress-strain relationship (hysteresis loop) using the least-square method and their transient changes after the release of avascularization were revealed. For healthy young persons, the slope of the hysteresis loop decreased due to the FMD, which corresponds to decrease in the elastic modulus. At the same time, the area of the loop increased after recirculation, which corresponds to the increase of the ratio of the loss modulus (viscosity) to the elastic modulus when the Voigt model is assumed. These results show a potential of the proposed method for thorough analysis of the transient change in viscoelasticity due to FMD.

Non-invasive ultrasonic measurement of the relative volume change of the arterial wall - first in vivo trial

2008 ◽  
Author(s):  
Hannes Mogensen ◽  
Tomas Jansson ◽  
Kjell Lindstrom ◽  
Hans W. Persson ◽  
Magnus Cinthio ◽  
...  
Keyword(s):  
Volume Change ◽  
Arterial Wall ◽  
Relative Volume ◽  
Ultrasonic Measurement ◽  
Non Invasive ◽  
Relative Volume Change
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