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The magnetic flux density of implantable electromagnetic blood flowmeter can not be made uniform, since the size of flowmeter probe must be very small for physiological reasons. The velocity distribution of blood flow is axially non-symmetrical everywhere in arteries. Mainly for the above reasons the blood flow can not be measured accurately by implantable(More)
BACKGROUND Knowledge of the physical properties of atherosclerotic plaque is essential when evaluating its vulnerability in a clinical setting. Such knowledge, however, is still difficult to obtain with the various approaches developed to date. METHODS AND RESULTS This article describes a noninvasive method for evaluating the regional elasticity (the(More)
High-frame-rate echocardiography using unfocused transmit beams and parallel receive beamforming is a promising method for evaluation of cardiac function, such as imaging of rapid propagation of vibration of the heart wall resulting from electrical stimulation of the myocardium. In this technique, high temporal resolution is realized at the expense of(More)
Noninvasive measurement of mechanical properties, such as elasticity, of the arterial wall, is useful for diagnosis of atherosclerosis. For assessment of mechanical properties, it is necessary to measure the deformation of the arterial wall. In this study, a modification of the previously proposed phased-tracking method was conducted to improve measurement(More)
PURPOSE Echocardiography is a widely used modality for diagnosis of the heart. It enables observation of the shape of the heart and estimation of global heart function based on B-mode and M-mode imaging. Subsequently, methods for estimating myocardial strain and strain rate have been developed to evaluate regional heart function. Furthermore, it has(More)
Mechanical properties of the arterial walls are significantly altered by atherosclerosis, and various studies have been recently conducted to measure the regional elastic properties (radial strain) of the arterial wall. We have developed a phase-sensitive correlation-based method, namely, the phased-tracking method, to measure the regional radial strain. On(More)
BACKGROUND We previously reported the arterial elasticity value we measured to reflect the characteristic features of vessel walls, and to possibly be useful for detecting early stage atherosclerosis in type 2 diabetes. Obesity, especially visceral adiposity, is well known to play a crucial role in the development of metabolic disorders and atherosclerosis.(More)
  • Hiroshi Kanai
  • 2005
Though myocardial viscoelasticity is essential in the evaluation of heart diastolic properties, it has never been noninvasively measured in vivo. By the ultrasonic measurement of the myocardial motion, we have already found that some pulsive waves are spontaneously excited by aortic-valve closure (AVC) at end-systole (T0). These waves may serve as an ideal(More)
Myocardial motion exhibits frequency components of up to 100 Hz, as found by a phased tracking method. To simultaneously measure the rapid and minute velocity signals at multiple points along the surface of the left ventricle (LV), in this study, conventional ultrasonic diagnosis equipment was modified to allow 10 scan lines from a sector scanner to be(More)