Advanced Technology Laboratories, Inc.

Roy B Peterson

Helen Frances Routh

Jeffry E Powers

Jens Ulrich Quistgaard

Thanasis Loupas

Patrick Rene Pesque

Aline Laure Criton

Marshall T Robinson

Patrick Rene' Pesque

Charles W Powrie, Jr

An ultrasonic diagnostic imaging system and method are described by which a fundamental frequency signal is transmitted into the body and harmonic (nonlinear) echo returns are received from the transmission. The harmonic echo signals are Doppler processed and displayed. The harmonic Doppler signals may be displayed alone, or in combination with a fundamental frequency or harmonic grayscale image. In a preferred embodiment harmonic signals returned from moving tissue are segmented on an intensity or frequency basis and displayed. The inventive apparatus and method provide highly resolved ultrasonic images of moving tissue which are substantially unobscured by image clutter from structures or tissue in the near field.

Ultrasonic harmonic doppler imaging

An ultrasonic imaging system is provided which produces signals representative of tissue motion through amplitude detection of echo signals from which stationary clutter has been removed. Tissue motion may be distinguished from noise and flow signals on the basis of the dynamic range of the detected signals. The tissue motion signals may be displayed in combination with B mode signals to augment images of moving tissue, or in a two dimensional image in combination with B mode and Doppler image information. A sequence of gated tissue motion images of the heart may be displayed with each image of a different phase of the heart cycle displayed in a different color. The sequence may be played in a real time sequence, or the images accumulated in a common static image which overlay and hence mask one another, thereby revealing subtle differences in motion from one phase of the heart cycle to another.

Medical ultrasonic power motion imaging

An ultrasonic diagnostic system simultaneously monitors the Doppler signal of a plurality of sample volumes within the body of a patient which are aligned around a point of diagnostic interest within the body. The Doppler signal of the sample volume which best satisfies a predetermined criterion, such as that exhibiting the greatest Doppler signal power, is displayed to the user. When a different sample volume meets the criterion the Doppler signal display changes to display the Doppler signal of the newly identified sample volume. In one embodiment the spectral Doppler displays of a number of sample volumes are displayed concurrently and that which best satisfies the chosen criterion is identified to the user. In another embodiment the identified sample volume is identified in a B mode display of the sample volume area while the spectral Doppler display from the identified sample volume is displayed. The two dimensional B mode display can also be extended to a three dimensional display of a volume of individual sample volumes.

Multiple sample volume spectral Doppler

A technique for continuously determining and displaying the peak and mean velocities of spectral Doppler information is disclosed. Received spectral Doppler data is examined over a predetermined period to determine the signal to noise ratio of the Doppler signals. Individual instantaneous measurements, or lines, of Doppler spectral information are analyzed in the power versus frequency domain to compare the line information against a noise threshold determined by the signal to noise ratio. The maximum frequency signal component is thereby identified as the peak velocity of the spectral line. Mean velocity is calculated as an intensity weighted mean about the maximum power frequency of the line data. The identified peak and mean velocities are displayed in contrasting colors or shades on a continuously updated and displayed flow velocity versus time spectral display.

Continuous display of peak and mean blood flow velocities

An ultrasonic color flow information processing system receives ultrasonic Doppler information signals which are used to develop a map of color flow display information of fluid flow. The system processes the Doppler information through autoregressive spectral estimation, which models the Doppler information as the output of an all-pole filter driven by white noise. For real-time utilization, the estimation of poles of the filter model is restricted to the estimation of two poles, one representative of tissue and one representative of fluid flow. The two poles and the white noise power parameter of the model are analyzed in accordance with certain criteria to select for display one of the poles as that representative of fluid flow.

Ultrasonic color flow imaging using autoregressive processing

An ultrasonic diagnostic system for measuring fluid flow velocities through Doppler techniques is provided which eliminates the effects of tissue motion from fluid flow velocity information. In a preferred embodiment Doppler information signal are discriminated to determine the presence of signal components resulting from moving tissue, which signal components are located at frequencies of a Doppler spectrum other than the predetermined frequency location of stationary tissue signals. The tissue motion signal components present are shifted to the predetermined frequency location and removed by high pass filtering the Doppler signals. The remaining signals are then shifted back to their original frequency location and transmitted to a Doppler velocity estimator for further processing of the fluid flow velocity information and ultimate display of the information. To overcome problems of Doppler frequency inaccuracies at discrete spatial positions, the Doppler signals from a plurality of neighboring spatial locations are examined in the aggregate to determine the frequency location of tissue motion signal components.

Growing community of inventors

Redmond, WA, United States of America

Roy B Peterson