Spectra of Ultrasound Doppler Response Using Plane-Wave Compounding Technique

Abstract

Within the framework of a simple model of the sensitivity function, the Doppler spectra are considered for different ways of generating response signals using plane wave compounding. A Doppler spectrum is obtained for coherent compounding of signals received at different steering angles of waves during their period of changing. Compared to traditional diagnostic systems, the Doppler spectrum width is increased only by limiting the duration of the signals. There is no additional increase in the spectrum width if the compound signals are formed by adding with cyclic permutation, in which signals from each new wave angle are compounded. When a Doppler signal is formed directly from Doppler signals at different steering angles, the spectral width increases both in comparison with the traditional method of sensing with stationary focused ultrasound fields and with the case of coherent signal compouding. The obtained increase in the spectral width has an intrinsic physical meaning. The increase in width is connected with a dynamic change in the Doppler angle, which increases the interval of apparent projections of the velocities of motion of inhomogeneities along the direction of transmitting of a plane wave without inclination.