Internal pressure dependence on viscoelasticity of arterial wall by ultrasonic measurement

Abstract

Previously, we proposed an ultrasonic measurement method of arterial wall elasticity for the early detection of arteriosclerosis. Since vascular wall elasticity depends on blood pressure, in this study, the elasticity and viscosity were estimated using the hysteresis loop determined between the incremental strain in the wall and internal pressure by altering the internal pressure in the phantom and in vivo experiments. Consequently, both the estimated elasticity and viscosity increased with the internal pressure. Moreover, the slope of each hysteresis loop was larger than that of the approximated curve for the lowest blood pressures of the hysteresis loops with different internal pressures, as the blood pressure changed in the order of several hertz within a single heartbeat. Hence, we conclude that measuring both the blood pressure and the elastic and viscous moduli would be beneficial in comprehensively investigating more vessel wall properties that change with the progression of arteriosclerosis.

Robust adversarial learning model to segment non-speckle regions in blood flow echo

“…1) Ultrasonic measurement is one of the methods that can measure the cardiovascular function and in vivo blood properties noninvasively. Previous studies have developed in ultrasonic cardiovascular characterization such as vector flow [2][3][4] wall shear stress [5][6][7] wall roughness 8,9) wall displacement 10,11) and red blood cell (RBC) aggregation. [12][13][14] In cardiovascular ultrasound imaging, weak blood flow echo is obscured by clutter components from blood vessel walls and surrounding tissues, which are seen as stationary signals.…”

Detection of free-swimming fish passing through a narrow passage using MHz-band ultrasonic reflected and transmitted waves

“…Low-frequency ultrasound with long wavelengths is usually used in underwater measurement and communication to propagate ultrasound over long distances with little attenuation. [7][8][9][10][11][12] HF ultrasound, such as MHz-band ultrasound with short wavelengths, has been used for a variety of purposes, including medical applications [13][14][15][16][17][18] and nondestructive testing. [19][20][21][22] Some studies in the field of hydroacoustics have used HF ultrasound, which can be used to measure shorter distances compared with low-frequency ultrasound.…”