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

Abstract

For the early diagnosis of atherosclerosis, our group developed an ultrasound probe that can simultaneously measure blood pressure and vessel diameter at the same position. However, since the developed probe requires the vessel to be deformed by the pushing to measure the blood pressure, it affects the estimation of the elastic modulus. In the present study, we derived a series of equations to estimate the elastic modulus considering the pushing pressure applied by the ultrasound probe and the resultant deformation of the blood vessel. The validity of the proposed method was verified by numerical calculations, and then it was applied to in vivo measurements. The proposed method reduced the variations in the elastic modulus estimates with the different pushing pressures compared with the conventional method.

Internal pressure dependence on viscoelasticity of arterial wall by ultrasonic measurement

“…Thus, the blood pressure waveform can be measured using the linear probe developed by our research group. [19][20][21] The linear probe was connected to an ultrasonic diagnostic device (Prosound F75; Aloka, Japan). The center frequency, sampling frequency and frame rate were set at 7.5 MHz, 40 MHz and 252 Hz, respectively.…”

“…Therefore, Arakawa et al have developed an ultrasound probe with a center frequency of 7.5 MHz that can measure blood pressure waveform with a central element. [19][20][21] Since the radial artery is close to the skin and just above the radius, the pressure waveform can be obtained by pressing the probe, including the piezoelectric element, against the radial artery through the skin. The thickness change in the radial artery cannot be measured because of the insufficient distance resolution.…”

“…In in vivo experiments, the diastolic blood pressure was varied in the radial artery by altering the height of the radial artery from the heart, the hysteresis loops between the blood pressure and inner diameter were obtained, and the viscoelasticity was estimated using the developed probes. [19][20][21] 2. Experimental method 2.1.…”

Ultrasonic complex vibration source equipped with a step horn with a welding tip and its welding characteristics

“…Ultrasonic vibration is widely used for non-contact and nondestructive inspection and measurement [1][2][3][4][5][6][7][8][9] and for applications including ultrasonic welding and ultrasonic processing. [10][11][12] Ultrasonic welding does not require the application of external heat to the objects for welding; thus, this method is suitable for welding dissimilar metals that cannot be welded by hot welding methods due to their different melting points.…”

Ultrasonic measurement of thickness of carotid arterial wall using its natural longitudinal displacement

“…Ultrasound is effective because it is non-invasive for the diagnosis of lifestyle diseases. [4][5][6] Many studies have assessed ultrasound application to various organs such as the blood vessels, 7) heart, 8,9) liver, 10) blood, 11) skin, 12) and bones. 13) Many research have been conducted on high-intensity focused ultrasound therapy 14) and its safety.…”