Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-02-17
2001-02-27
Jaworski, Francis J. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S458000
Reexamination Certificate
active
06193662
ABSTRACT:
This invention relates to ultrasonic diagnostic imaging systems and, in particular, to pulse inversion harmonic ultrasonic diagnostic imaging at high frame rates or line densities of display.
U.S. Pat. No. 5,706,819, of which I am a co-inventor, describes a signal processing technique which separates fundamental and harmonic signal components in received ultrasonic echo signals. This technique, known in ultrasound as “pulse inversion,” is a two pulse technique in which two pulses of opposing polarity (phase) are successively transmitted to the same location in the body. Echoes are received following each transmission in which fundamental signal components are out of phase due to the opposing polarity of the transmit pulses, but the higher order harmonic signal components, being quadratic in nature, are not. Summing the two echoes will cancel the opposing fundamental components and reinforce the harmonic components, leaving a cleanly separated harmonic signal without the need for conventional filters. Subtracting the two echoes will have the opposite result, canceling the harmonic signal components and reinforcing the fundamental (linear) signal components. In a similar manner, subtraction leaves a cleanly separated fundamental echo signal.
Pulse inversion is a two pulse technique, however, meaning it is necessary to scan each acoustic line twice in order to form a single image. This means that the time required to acquire all of the scanlines of an image is approximately doubled as compared to conventional single pulse imaging. The time to acquire all of the scanlines of an image frame determines the frame rate of display, which will approximately halve with a two pulse technique. It is desirable to have as high a frame rate as possible so that realtime imaging is produced which shows tissue motion smoothly and with little interframe discontinuity as a scanhead is moved when surveying a patient's anatomy.
In accordance with the principles of the present invention, pulse inversion harmonic imaging is carried out at a high frame rate of display and a high line density. In the inventive technique transmit pulses of opposing polarity (phase) are transmitted along transmit scanlines at adjacent positions in the image field. The received scanlines are combined to separate harmonic signals on image lines which are intermediate the positions of the transmitted scanlines. In one embodiment transmit scanlines are paired to overlap, enabling the formation of image lines of separated harmonic signals at and between the positions of the transmitted scanlines. The spacing of the transmitted scanlines can be varied to vary both the line density of the ultrasonic image and the image frame rate of display. In another embodiment transmit pulses of opposing polarity (phase) are transmitted and multiple scanlines are received in response to each transmitted scanline. Received scanlines from opposite polarity pulses are combined to produce harmonic images at a high frame rate of display. By combining received scanlines in a temporally consistent manner, motion artifacts are reduced. In yet another embodiment received scanlines are combined both additively and differentially to simultaneously produce separated fundamental and harmonic scanline signals, which may then be variably blended together to form images which take advantage of the characteristics of both fundamental and harmonic signal information.
REFERENCES:
patent: 4549210 (1985-10-01), Dulapa
patent: 5318033 (1994-06-01), Savord
patent: 5390674 (1995-02-01), Robinson et al.
patent: 5431167 (1995-07-01), Savord
patent: 5462057 (1995-10-01), Hunt et al.
patent: 5577505 (1996-11-01), Brock-Fisher et al.
patent: 5623928 (1997-04-01), Wright et al.
patent: 5632277 (1997-05-01), Chapman et al.
patent: 5667373 (1997-09-01), Wright
patent: 5706819 (1998-01-01), Hwang et al.
patent: 5902243 (1999-05-01), Holley et al.
patent: 5980458 (1999-11-01), Clark
patent: 6099471 (2000-08-01), Torp et al.
patent: 6117082 (2000-09-01), Bradley et al.
patent: 99/30617 (1999-06-01), None
ATL Ultrasound
Jaworski Francis J.
Yorks, Jr. W. Brinton
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