Noninvasive evaluation of spatial distribution of thickness change in myocardium

For the noninvasive diagnosis of heart disease based on movability of the myocardium in the heart wall, the authors have already developed a new method. By the method, velocity signals of the heart wall with small amplitudes less than 10 micrometer on the motion resulting from a heartbeat with large amplitude of 10 mm can be successfully detected with sufficient reproducibility in the frequency range up to several hundred Hertz. The method is applied to multiple points which are set in the heart wall on a ultrasonic beam so that the spatial (depth) distributions of the velocity at these points are obtained. In this paper, from the spatial distributions, the spatial distribution of instantaneous change in thickness is noninvasively evaluated. From in vivo experimental evaluation, clear differences are obtained between healthy subjects and patients with cardiomyopathy, which cannot be obtained by the previously proposed tissue Doppler imaging. This new method offers potential for research on noninvasive acoustical diagnosis of myocardial local movability.