Broadband blended fundamental and harmonic frequency ultrasonic diagnostic imaging

Abstract

An ultrasound system is described which produces blended fundamental and harmonic frequency images. Successively transmitted, differently modulated pulses are transmitted by an ultrasound probe and both fundamental and harmonic frequencies are received in response. The echo signals received from the two pulses are processed by pulse inversion, producing cleanly separated bands of fundamental and harmonic signals in which undesired components have been cancelled. Since the two bands have been separated by signal cancellation rather than filtering, the two bands are allowed to overlap, providing broadband signals in each band. The bands are filtered by bandpass filtering to define the fundamental and harmonic signals to be imaged. The signals are detected, and the detected signals are combined after weighting to produce a blended fundamental / harmonic image.

Description

[0001] This application claims the benefit of priority to US Application No. 62 / 109121, filed January 29, 2015, which is hereby incorporated by reference in its entirety. technical field [0002] The present invention relates to ultrasonic diagnostic imaging systems, and in particular to the use of hybrid fundamental and harmonic frequency ultrasound images. Background technique [0003] Harmonic imaging is used in ultrasound imaging to image ultrasound contrast agents and overcome reverberant clutter that can occur at the fundamental frequency. Although echo signals at higher harmonic frequencies will exhibit the attenuating effect of depth-dependent frequency attenuation, today's ultrasound systems are sensitive enough to largely overcome the attenuation at shallower depths in the body. The downside. This effect is prevalent only in tissue harmonic imaging, where near-field clutter from rib artifacts is avoided by a slower development of the harmonic signal components wit...

AI Technical Summary

Problems solved by technology

However, the filtering necessary to separate the fundamental and harmonic frequencies creates an undesirable trade-off

In order to cleanly separate the signals into their two distinct bands, the bandwidth of the filters must be narrowly defined so that there is no band overlap, which especially disadvantageously limits the fundamental signal to a narrow band and the resulting limited resolution

Broadening the bands for wider-band imaging can cause the two bands to overlap and reduce the unique characteristics and benefits of each signal type

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