From Hitachi Medical Corporation (HMC), sales, marketing and service in the US by Hitachi Medical Systems America Inc.;
Powerful, flexible, and fast, the HI VISION™ 8500 - EUB-8500 diagnostic ultrasound scanner combines leading edge technologies with user-oriented operation for exceptional imaging and functionality.
Available exclusively on the 8500, SonoElastography provides a new perspective on the physical properties of tumors and masses by determining and displaying the relative stiffness of tissue.

From Hitachi Medical Corporation (HMC);
The HI VISION™ 6500 - EUB-6500 high resolution digital ultrasound system offers advanced clinical imaging, enhanced operating efficiency, and remarkable clinical flexibility, all in robust and versatile configuration that simply represents a better clinical solution in a variety of real-world, real-work arenas.

The M-mode (Motion-mode) ultrasound is used for analyzing moving body parts (also called time-motion or TM-mode) commonly in cardiac and fetal cardiac imaging. The application of B-mode and a strip chart recorder allows visualization of the structures as a function of depth and time. The M-mode ultrasound transducer beam is stationary while the echoes from a moving reflector are received at varying times.
A single beam in an ultrasound scan is used to produce the one-dimensional M-mode picture, where movement of a structure such as a heart valve can be depicted in a wave-like manner. The high sampling frequency (up to 1000 pulses per second) is useful in assessing rates and motion, particularly in cardiac structures such as the various valves and the chamber walls.

The matrix size is the number of data points collected in one, two or three directions. Normally used for the 2D in plane sampling. The display matrix may be different from the acquisition matrix, although the latter determines the resolution.

The Nyquist frequency describes the highest frequency that can be sampled in a pulsed ultrasound system. To record higher frequencies the zero baseline can be shifted in the desired direction.

See also Nyquist Limit, and Sampling Rate.