Phase unwrapped velocity display for ultrasound medical imaging

• US 7,682,311 B2
• Filed: 09/22/2005
• Issued: 03/23/2010
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Simopoulos, Constantine, Ustuner, Kutay F.
• Primary Examiner(s): Winakur; Eric F
• Assistant Examiner(s): BOR, HELENE CATHERINE
• Application Number:
  US11/233,550
• Publication Number:
  US 20070066896A1
• Time in Patent Office: 1,643 Days
• Field of Search: 600/453, 600/465, 600/454, 706/76
• US Class Current: 600/454
• CPC Class Codes: G01S 15/584 with measures taken for suppressing velocity ambiguities, i.e. anti-aliasing
• CPC Class Codes: G01S 15/8979 Combined Doppler and pulse-echo imaging systems

Abstract

Phase unwrapping is applied to velocity data to remove aliasing artifacts. Phase unwrapping is applied on multidimensional regions of velocity data. The unwrapped velocity image is displayed. The displayed image may have high sensitivity to slow motion but may also avoid aliasing of fast motion despite being undersampled.

Claims

1. A method of imaging motion with ultrasound, the method comprising:

setting a pulse repetition interval used throughout an entire scan in a first direction;

applying a multidimensional phase unwrapping to a first set of ultrasound motion data representing a multidimensional region;

the phase unwrapping being without data acquired with a different pulse repetition; and

generating an image from phase unwrapped ultrasound motion data.

2. The method of claim 1 wherein applying to the first set of ultrasound motion data comprises applying to a frame of velocity data.

3. The method of claim 1 wherein applying multidimensional phase unwrapping comprises determining a two dimensional phase unwrapping to each value of the first set of ultrasound motion data, the multidimensional region being an area.

4. The method of claim 1 wherein applying multidimensional phase unwrapping comprises determining a three dimensional phase unwrapping to each value of the first set of ultrasound motion data, the multidimensional region being a volume.

5. The method of claim 1 further comprising:

identifying the first set of ultrasound motion data prior to applying the multidimensional phase unwrapping, the identified first set of ultrasound motion data being associated with a systole period of a heart cycle;

wherein applying comprises applying to the identified first set of ultrasound motion data.

6. The method of claim 1 wherein generating the image comprises generating the image without aliasing wherein the ultrasound motion data is undersampled as a function of the pulse repetition interval.

7. The method of claim 1 wherein generating the image comprises mapping the phase unwrapped ultrasound motion data to a color scale.

8. The method of claim 1 further comprising:

applying multidimensional phase unwrapping to a second set of ultrasound motion data representing the multidimensional region, the second set of ultrasound motion data corresponding to a second scan direction different than the first scan direction; and

determining velocity values for each of a plurality of locations in the multidimensional region, each velocity value being a function of phase unwrapped ultrasound motion data from the first and second sets of motion data;

wherein generating the image comprises generating the image from the velocity values.

9. A system for imaging motion with ultrasound, the system comprising:

a first processor operable to unwrap phase representing velocities in a multidimensional region, the phase corresponding to ultrasound motion data acquired by setting a pulse repetition interval used throughout an entire scan, the unwrapping of phase using a velocity value from the scan as having a true phase;

a second processor operable to assign image value to spatial locations associated with the phase unwrapped velocities as a function of the phase unwrapped velocities; and

a display operable to generate an image from the image values.

10. The system of claim 9 wherein the multidimensional region is an area and the first processor is operable to unwrap phase two dimensionally.

11. The system of claim 9 wherein the multidimensional region is a volume and the first processor is operable to unwrap phase three dimensionally.

12. The system of claim 9 wherein the velocities are undersampled as a function of the pulse repetition interval.

13. The system of claim 9 wherein the second processor comprises a look-up table operable to map the phase unwrapped velocities to a color scale of the image values.

14. The system of claim 13 where the color scale corresponds to a fixed velocity range.

15. The system of claim 13 where the color scale is adjustable and spans the range of unwrapped velocities currently being displayed.

16. The system of claim 9 wherein the first processor is operable to unwrap phase multidimensional of velocities representing the same locations of the multidimensional region from different interrogation directions and is operable to determine the velocity vector as a function of two or more unwrapped velocities for each of the locations.

17. In a computer readable storage medium having stored therein data representing instructions executable by a programmed processor for imaging motion with ultrasound, the storage medium comprising instructions for:

correcting velocity values with multidimensional phase unwrapping, each velocity value being a function of phase unwrapped ultrasound motion data acquired at a same pulse repetition interval for a scan and one of the velocity values being used for phase unwrapping as an unaliased velocity; and

generating a display of the corrected velocity values.

18. The storage medium of claim 17 wherein the velocity values are undersampled as a function of the pulse repetition interval.

19. The storage medium of claim 17 wherein generating the display comprises mapping colors to the corrected velocity magnitude.

20. The storage medium of claim 19 where the color scale correspond to a fixed velocity range.

21. The storage medium of claim 19 where the color scale is adjustable and spans the range of unwrapped velocities currently being displayed.

22. The storage medium of claim 18 wherein correcting the velocity values comprises correcting velocities values for a same location associated with different scan directions;

further comprising;

determining a corrected velocity vector for the location as a function of the corrected velocity values;

wherein generating the display comprises generating the display as a function of the corrected velocity vector.