Atl Ultrasound, Inc.

Koninklijke Philips Corporation N.v.

Sunnybrook Health Science Centre

Peter N Burns

David N Roundhill

Jeffry E Powers

Michalakis Averkiou

Juin-Jet Hwang

David Hope Simpson

Jeremy D Wiggins

David Hope-Simpson

An ultrasonic diagnostic imaging apparatus and method are provided for segmenting signals from nonlinear targets such as microbubble contrast agents. Received echo signals are separated into their constituent linear and nonlinear components by a Doppler filter using pulse inversion separation. A threshold level is derived from an estimate made of the contributions to the echo signal from linear scattering and noise. Echo signals which exceed the threshold level are segmented as nonlinear (microbubble-originating) signals and displayed as such, whereas signals not exceeding the threshold are suppressed in the image display.

Ultrasonic harmonic image segmentation

An ultrasonic diagnostic imaging system and methods are described which produce tissue harmonic ultrasonic images from harmonic echo components of a transmitted fundamental frequency. Fundamental frequency waves are transmitted by an array transducer to focus at a focal depth. As the transmitted waves penetrate the body, the harmonic effect develops as the wave components begin to focus. The harmonic response from the tissue is detected and displayed, while clutter from the fundamental response is reduced by excluding fundamental frequencies. The technique is especially useful for imaging the endocardial tissue of the heart.

Ultrasonic tissue harmonic imaging

An ultrasonic diagnostic imaging method and apparatus are presented which separates broadband linear and nonlinear echo signal components while simultaneously distinguishing the effects of motion. The inventive method maps ultrasonic echo signals in the r.f. (time) domain to Doppler shift frequencies in the Doppler domain in a way that depends upon the linearity of the echoes. The inventive method does this by analyzing the phase shifts between successive echoes. Apparatus is described in which a Doppler echo ensemble is acquired by a transmit sequence of cyclically phase-varying waveforms. When the echoes of the ensemble are combined during Doppler processing, the resulting Doppler spectrum is divided into separate regions, with odd harmonics (e.g., linear signal components) residing in one region and even harmonics (e.g., second harmonic signal components) residing in another region. In a preferred embodiment a Doppler wall filter is used to delineate a particular type of signal information for processing, such as tissue motion, harmonic contrast agent, or tissue harmonic imaging information.

Pulse inversion doppler ultrasonic diagnostic imaging

An ultrasonic diagnostic imaging system and methods are described which produces ultrasonic images from harmonic echo components of a transmitted fundamental frequency. Preferably, a programmable digital filter is used to pass harmonic echo components for image processing to the exclusion of fundamental frequency signals. In a preferred embodiment, artifacts are removed by producing decorrelated replicas of the harmonic signals, which are then combined and used for imaging. To produce an image in the presence of depth dependent attenuation of high frequency echo signals, both fundamental and harmonic echo signals are processed and used to produce an image blended from components of both fundamental and harmonic echo signals.

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Toronto, Canada

Peter N Burns