EKG driven CT image reconstruction for cardiac imaging

• US 6,438,196 B1
• Filed: 06/28/2001
• Issued: 08/20/2002
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Cesmeli, Erdogan
• Primary Examiner(s): Bruce, David V.
• Assistant Examiner(s): Hobden, Pamela R.
• Application Number:
  US09/681,942
• Time in Patent Office: 418 Days
• Field of Search: 378/8, 378/4, 378/20, 378/95, 600/509, 600/428
• US Class Current: 378/8
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal

Abstract

A method for reconstructing an image of a beating heart includes decomposing at least one electrocardiogram (EKG) RR interval, tagging projection data with cardiac phase information based on the decomposition, and reconstructing an image using the tagged data.

Claims

1. A method for reconstructing an image of a beating heart, said method comprising:

decomposing at least one electrocardiogram (EKG) RR interval;

tagging projection data with cardiac phase information based on the decomposition; and

reconstructing an image using the tagged data.

2. A method in accordance with claim 1 wherein decomposing at least one EKG comprises dividing each RR interval into a plurality of subwaves.

3. A method in accordance with claim 2 wherein dividing each RR interval comprises applying a wavelet transform to the EKG signal to produce a plurality of frequency bands.

4. A method in accordance with claim 2 wherein decomposing further comprises identifying a plurality peaks in a selected one of the frequency bands.

5. A method in accordance with claim 4 wherein decomposing further comprises:

identifying at least one of a P peak, a Q peak, a R peak, a S peak and a T peak using the identified peaks in the selected frequency band; and

determining cardiac phase information based on the at least one of a P, Q, R, S and T peak.

6. A method in accordance with claim 5 wherein tagging projection data further comprises:

collecting a plurality of projection data utilizing a CT scanning device; and

correlating the cardiac phase information with each of the projection data collected.

7. A method in accordance with claim 1 wherein reconstructing an image comprises:

collecting a plurality of projection data for multiple cardiac cycles;

tagging the projection data collected during each cardiac cycle with cardiac phase information; and

combining the projection data tagged with like cardiac phase information.

8. A system for reconstructing an image of a beating heart, said system comprising an electrocardiogram (EKG) device, a computed tomography (CT) device electrically coupled to the EKG device, and a processor electrically coupled to at least one of the EKG device and the CT device, said system configured to:

decompose at least one electrocardiogram (EKG) RR interval;

determine cardiac phase information based on the decomposition; and

reconstruct an image using the phase information.

9. A system in accordance with claim 8 wherein to decompose at least one EKG, said system configured to:

utilize a wavelet transform to produce a plurality of frequency bands; and

identify a plurality of peaks in a selected one of the frequency bands.

10. A system in accordance with claim 9 wherein to decompose at least one EKG, said system further configured to determine at least one of a P wave, a Q wave, a R wave, a S wave and a T wave within the selected frequency band based on the identified peaks.

11. A system in accordance with claim 10 wherein to determine cardiac phase information, said system further configured to determine cardiac phase information based on the at least one of the P, Q, R, S and T peak.

12. A system in accordance with claim 8 wherein said system further configured to tag projection data with the cardiac phase information.

13. A system in accordance with claim 12 wherein to tag projection data, said system further configured to:

collect a plurality of projection data utilizing a CT scanning device; and

correlate at least one of the cardiac phases with each of the projection data collected.

14. A system in accordance with claim 8 wherein to reconstruct an image, said system configured to collect a plurality of projection data for multiple cardiac cycles.

15. A system in accordance with claim 14 wherein to reconstruct an image, said system further configured to:

tag the projection data collected during each cardiac cycle with cardiac phase information; and

combine the projection data tagged with like cardiac phase information.

16. A computer readable medium encoded with a program executable by a computer for reconstructing images of a beating heart utilizing data gathered using a computed tomography (CT) device and an electrocardiogram (EKG) device, said program configured to instruct the computer to:

decompose at least one EKG RR interval into at least one of a P wave, a Q wave,

a R wave, a S wave, and a T wave; and

tag projection data with cardiac phase information based on the decomposition.

17. A computer readable medium in accordance with claim 16 wherein to decompose at least one EKG RR interval, said program further configured to instruct the computer to utilize a wavelet transform to extract a plurality of frequency bands from the EKG signal.

18. A computer readable medium in accordance with claim 17 wherein to decompose, said program further configured to instruct the computer to:

determine peaks in a selected one of the frequency bands; and

identify at least one of a P peak, a Q peak, a R peak, a S peak, and a T peak based on the determined peaks.

19. A computer readable medium in accordance with claim 18 wherein to tag projection data, said program further configured to instruct the computer to determine cardiac phase information based on the at least one of a P, Q, R, S, and T peak.

20. A computer readable medium in accordance with claim 19 wherein to tag projection data, said program further configured to instruct the computer to correlate the phase information with projection data.

21. A method for determining cardiac phase information used to reconstruct an image of a beating heart, said method comprising:

decomposing at least one EKG RR interval; and

determining cardiac phase information based on the decomposition.

22. A method in accordance with claim 21 wherein decomposing comprises applying a wavelet transform to an EKG signal to determine a plurality of frequency bands.

23. A method in accordance with claim 22 wherein decomposing further comprises determining a plurality of peaks within a selected one of the frequency bands.

24. A method in accordance with claim 23 wherein decomposing further comprises identifying at least one of a P peak, a Q peak, a R peak, a S peak, and a T peak based on the plurality of peaks.

25. A method in accordance with claim 21 wherein determining cardiac phase information comprises utilizing the at least one of a P, Q, R, S, and T peak to determine the cardiac phase information.

26. A system for reconstructing an image of a beating heart, said system comprising:

an electrocardiogram (EKG) device configured to collect EKG data;

a computed tomography (CT) device electrically coupled to the EKG device configured to acquire projections data; and

a processor electrically coupled to at least one of the EKG device and the CT device, said processor configured to;

utilize a wavelet transform to decompose at least one electrocardiogram (EKG) RR interval into a plurality of frequency bands;

identify a plurality of peaks in a selected one of the frequency bands;

determine cardiac phase information based on the identified peaks;

tag projection data with the cardiac phase information; and

reconstruct an image using the phase information.

27. A system in accordance with claim 26 wherein to utilize a wavelet transform to decompose said processor further configured to determine at least one of a P wave, a Q wave, a R wave, a S wave and a T wave within the selected frequency band based on the identified peaks.

28. A system in accordance with claim 27 wherein to determine cardiac phase information, said processor further configured to determine cardiac phase information based on the at least one of the P, Q, R, S and T peak.

29. A system in accordance with claim 26 wherein to reconstruct and image, said EKG device further configured to acquire a plurality of projection data for multiple cardiac cycles.

30. A system in accordance with claim 26 wherein said system further comprises a reconstructor electrically coupled to at least one of the processor, the CT device, and the processor, wherein to reconstruct an image, said reconstructor configured to combine the projection data tagged with like cardiac phase information.

31. A computer readable medium encoded with a program executable by a computer for reconstructing images of a beating heart utilizing data gathered using a computed tomography (CT) device and an electrocardiogram (EKG) device, said program configured to instruct the computer to:

utilize a wavelet transform to extract a plurality of frequency bands from the EKG signal;

determine peaks in a selected one of the frequency bands; and

identify at least one of a P peak, a Q peak, a R peak, a S peak, and a T peak based on the determined peaks; and

tag projection data with cardiac phase information based on the decomposition.

32. A computer readable medium in accordance with claim 31 wherein to tag projection data, said program further configured to instruct the computer to:

determine cardiac phase information based on the at least one of a P, Q, R, S, and T peak; and

correlate the phase information with projection data.