Measurement of propagation of local and minute contractile response in layered myocardium

Abstract

The in vivo measurement of the contractile response caused by electrical excitation has been studied to detect myocardial ischemia in its early stages. In the present study, we used our previously proposed local velocity estimator to measure the two-dimensional distribution of the strain rate using high-density beam scanning to obtain propagation of the local and minute contractile response in the heart walls of healthy humans. Alternate layers of contraction and relaxation were observed around the time phase representing the onset of the conduction of electrical excitation. The contraction propagated along the direction of the myocardial fiber in the myocardial layer. These results indicated that the electrical excitation conducted in each myocardial layer and the transmural shearing deformation occurred at the boundary between alternate layers of contraction and relaxation. The measurement of the propagation of the local and minute contractile response can reveal the effective contraction with the transmural shearing deformation.

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

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Determination of thermal and mechanical indices of an ultrasound probe with an inclined beam-axis in accordance with the new JIS (or IEC Standards)

“…Research on ultrasonic diagnosis [1][2][3][4][5][6][7][8][9][10][11][12][13] and ultrasonic therapy 14,15) are important in developing safe and highperformance medical ultrasonic equipment. As for ultrasonic diagnostic equipment, precise and practical test methods for the determination of thermal and mechanical indices related to medical diagnostic ultrasonic fields are required to ensure the safety of patients in diagnosis.…”

High-speed measurement of two-dimensional displacement of myocardium using element RF data of ultrasonic probe

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