HEART RATE DEMODULATION OF PERIODIC MOVEMENT IN ULTRASOUND DATA FOR OBJECT IDENTIFICATION

• US 20080119736A1
• Filed: 11/22/2006
• Published: 05/22/2008
• Est. Priority Date: 11/22/2006
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: DENTINGER, AARON MARK
• Granted Patent: US 8,050,476 B2
• Time in Patent Office: Days
• US Class Current: 600/455
• CPC Class Codes: A61B 8/02 Measuring pulse or heart rate
• CPC Class Codes: A61B 8/06 Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

A system and method for enhancing and displaying a target object, that generally comprises: a processor that demodulates the rate of movement of the target object to produce a demodulated signal; computes the power of the demodulated signal; creates an image sequence, based on the power of the demodulated signal, that comprises the enhanced periodic motion pixels; and forms an image sequence of the enhanced periodic motion pixels to form an image display of at least the target object; and an image display device to display the target object.

Claims

1. A method for enhancing a signal of a target object comprising the steps of,

Providing a rate of movement of said target object;

and

Demodulating said rate of said target object.

2. The method of claim 1, wherein said rate of movement is expressed as an autocorrelation sequence and wherein said step of demodulating comprises the step of down-mixing said autocorrelation sequence.

3. The method of claim 2, wherein said step of down-mixing comprises the steps of:

providing a complex phasor having a unity amplitude that is rotating at a constant frequency substantially equal to said heart rate; and

multiplying said autocorrelation sequence by said complex phasor.

4. The method of claim 3, wherein said down-mixing is in part accomplished using the following algorithm:

$R_{\mathrm{mixed}}<br><br>\left[n_t\right]=R<br><br>\left[n_t\right]<br><br>{\mathrm{<br><br>}}^{-\mathrm{j2\pi <br><br>}<br><br><br><br>f_{\mathrm{HR}}<br><br>n_t<br><br>T_s}$

5. The method of claim 3, wherein said autocorrelation sequence comprises one or more real and imaginary components.

6. The method of claim 1, wherein said pulsating rate is expressed as an autocorrelation sequence and wherein said step of demodulating comprises the step of applying a low pass filter to said autocorrelation sequence.

7. The method of claim 6, wherein said low pass filter comprises a digital, frequency selective filter.

8. The method of claim 1, wherein said rate of movement corresponds to a heart rate.

9. The method of claim 8, wherein said target object is an artery.

10. The method of claim 8, wherein said target object is a fetal heart.

11. The method of claim 1, wherein said rate of movement comprises a raw complex autocorrelation function.

12. The method of claim 1, wherein said rate of movement is provided by an external source.

13. The method of claim 1, further comprising the steps of:

calculating one or more statistics of one or more pixels corresponding to one or more non-moving noises;

determining an adaptive threshold for a magnitude of one or more object pixels based on one or more properties of said noise;

identifying said object pixels that correspond to one or more positive and negative velocities based on said threshold;

assigning labels to one or more of said object pixels that are substantially adjacent; and

locating said adjacent object pixels that define one or more objects based on one or more size and power criteria.

14. A system for automatically detecting an object associated with a rate of movement, comprising,

a processor for:

filtering a complex autocorrelation signal corresponding to said rate of movement;

demodulating said filtered complex autocorrelation signal;

calculating one or more statistics of one or more pixels corresponding to one or more non-moving noises;

determining an adaptive threshold for a magnitude of one or more object pixels based on one or more properties of said noise;

identifying said object pixels that correspond to one or more positive and negative velocities based on said threshold;

assigning labels to one or more of said object pixels that are substantially adjacent;

locating said adjacent object pixels that define one or more of said objects based on one or more size and power criteria; and

creating an image that comprises a location of one or more of said detected objects; and

a display device for displaying said image of said detected object.

15. A method for displaying a target object, comprising the steps of,

providing a rate of movement of said target object;

demodulating said rate of movement of said target object to produce a demodulated signal;

computing a power of said demodulated signal;

creating an image sequence, based on said power of said demodulated signal,

that comprises one or more enhanced periodic motion pixels; and

combining said image sequence of said enhanced periodic motion pixels with a second image sequence to form an image display.

16. The method of claim 15, wherein said step of computing comprises taking a magnitude of one or more autocorrelation pixels using the expression

A[n_x,n_v]=|R_demod[n_x,n_v]².

17. The method of claim 15, wherein said second image comprises a B-Mode image from an ultrasound scanner.

18. The method of claim 15, wherein said display comprises a duplex display.

19. The method of claim 15, further comprising the step of displaying said image display on a monitor.

20. A system that carries out the method of claim 15, comprising,

a processor that:

demodulates said provided rate of movement of said target object to produce a demodulated signal;

computes said power of said demodulated signal;

creates said image sequence, based on said power of said demodulated signal, that comprises said enhanced periodic motion pixels; and

combines said image sequence of said enhanced periodic motion pixels with a second image sequence to form an image display; and

an image display device.