METHODS AND APPARATUS FOR ULTRASOUND IMAGING

• US 20110040188A1
• Filed: 08/11/2010
• Published: 02/17/2011
• Est. Priority Date: 08/11/2009
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Aloka Medical, Ltd (Hitachi, Ltd.)
• Inventors: Tamura, Tadashi
• Granted Patent: US 8,480,590 B2
• Time in Patent Office: Days
• US Class Current: 600/454
• 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 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: A61B 8/13 Tomography A61B8/10, A61B8/12 take precedence; tomography for radiation diagnosis A61B6/02
• CPC Class Codes: A61B 8/488 involving Doppler signals

Abstract

Some embodiments include acquisition of color Doppler data, and detection of one or more transitions of the color Doppler data, each of the one or more transitions being between a first area representing flow velocity in a first direction and a second area representing flow velocity not in the first direction. A normalized energy function across one or more of the one or more transitions is calculated, a configuration of flow areas within the color Doppler data is determined, and aliasing corrections for the color Doppler data are determined based on the normalized energy functions and the configuration of flow areas.

Claims

1. A method comprising:

acquiring color Doppler data;

detecting one or more transitions of the color Doppler data, each of the one or more transitions being between a first area representing flow velocity in a first direction and a second area representing flow velocity not in the first direction;

calculating a normalized energy function across one or more of the one or more transitions;

determining a configuration of flow areas within the color Doppler data; and

determining aliasing corrections for the color Doppler data based on the normalized energy functions and the configuration of flow areas.

2. A method according to claim 1, wherein calculating the normalized energy function across a transition comprises:

calculating the sum of the absolute differences between each of one or more pairs of color Doppler values which are located on opposite sides of the transition; and

dividing said sum of the absolute differences by the number of the one or more pairs of color Doppler values.

3. A method according to claim 1, wherein determining the configuration of flow areas comprises:

determining if the color Doppler data includes single-inclusions, double-inclusions or triple-inclusions.

4. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining no aliasing corrections for the color Doppler data if the normalized energy function across one or more transitions is less than a preset threshold.

5. A method according to claim 4, wherein the preset threshold is a velocity corresponding to the Doppler shift frequency of half a pulse repetition frequency associated with the color Doppler data.

6. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining single aliasing correction for the color Doppler data of a flow area in contact with a transition if the normalized energy function across the transition is greater than a preset threshold.

7. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining no aliasing correction for the color Doppler data of a flow area in contact with a zero velocity area.

8. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining single aliasing correction for the color Doppler data of a flow area which is in contact with a zero flow area, and in contact with a transition with an opposite flow velocity area, wherein the normalized energy function across the transition is greater than a preset threshold.

9. A method according to claim 8, wherein the flow area for which single aliasing correction is determined is smaller than the opposite flow velocity area.

10. A method according to claim 8, wherein determining single aliasing correction comprises:

calculating a first total energy function of the color Doppler data based on single aliasing correction applied to one of the two flow areas (area A) and no aliasing corrections applied to the other one of the two flow areas (area B);

calculating a second total energy function of the color Doppler data based on single aliasing correction applied to area B and no aliasing corrections applied to area A; and

determining a smaller of the first and second total energy functions.

11. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining single aliasing correction for the color Doppler data of a flow area representing flow velocity in a first direction which is surrounded by a second flow area representing flow velocity in a second direction which is in contact with a zero velocity area; and

determining no aliasing correction for the color Doppler data of the second flow area.

12. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining single aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by a second flow area representing flow velocity in a second direction which is in contact with a zero velocity area; and

determining no aliasing correction for the color Doppler data of the second flow area if the normalized energy function across a transition between the first flow area and the second flow area is greater than a preset threshold.

13. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining double aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is in turn surrounded by and in contact with a third flow area representing flow velocity in the first flow direction which is surrounded by and in contact with a zero velocity area;

determining single aliasing correction for the color Doppler data of the second flow area; and

determining no aliasing correction for the color Doppler data of the third flow area.

14. A method according to claim 1, wherein, determining the aliasing corrections comprises:

determining double aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is in turn surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a zero velocity area;

determining single aliasing correction for the color Doppler data of the second flow area; and

determining no aliasing correction for the color Doppler data of the third flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is less than a first preset threshold and if the normalized energy function across a transition between the second flow area and the third flow area is greater than a second preset threshold.

15. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining no aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a zero velocity area;

determining single aliasing correction for the color Doppler data of the second flow area; and

determining no aliasing correction for the color Doppler data of the third flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is greater than a first preset threshold and if the normalized energy function across a transition between the second flow area and third flow area is greater than a second preset threshold.

16. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining triple aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a fourth flow area which is surrounded by and in contact with a zero velocity area;

determining double aliasing correction for the color Doppler data of the second flow area;

determining single aliasing correction for the color Doppler data of the third flow area; and

determining no aliasing correction for the color Doppler data of the fourth flow area.

17. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining triple aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a fourth flow area which is surrounded by and in contact with a zero velocity area;

determining double aliasing correction for the color Doppler data of the second flow area;

determining single aliasing correction for the color Doppler data of the third flow area; and

determining no aliasing correction for the color Doppler data of the fourth flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is greater than a preset threshold, if the normalized energy function across a transition between the second flow area and the third flow area is less than a second preset threshold, and if the normalized energy function across a transition between the third flow area and the fourth flow area is greater than a third preset threshold.

18. A method according to claim 1, wherein determining the aliasing corrections comprises:

determining single aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first flow direction which is surrounded by and in contact with a fourth flow area representing flow velocity in the second flow direction which is surrounded by and in contact with a zero velocity area;

determining double aliasing correction for the color Doppler data of the second flow area;

determining single aliasing correction for the color Doppler data of the third flow area; and

determining no aliasing correction for the color Doppler data of the fourth flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is less than a preset threshold, if the normalized energy function across a transition between the second flow area and the third flow area is less than a second preset threshold, and if the normalized energy function across a transition between the third flow area and the fourth flow area is greater than a third preset threshold.

19. A system comprising:

an aliasing correction processor to

acquire color Doppler data;

detect one or more transitions of the color Doppler data, each of the one or more transitions being between a first area representing flow velocity in a first direction and a second area representing flow velocity not in the first direction;

calculate a normalized energy function across one or more of the one or more transitions;

determine a configuration of flow areas within the color Doppler data; and

determine aliasing corrections for the color Doppler data based on the normalized energy functions and the configuration of flow areas.

20. A system according to claim 19, wherein calculation of the normalized energy function across a transition comprises:

calculation of the sum of the absolute differences between each of one or more pairs of color Doppler values which are located on opposite sides of the transition; and

division of said sum of the absolute differences by the number of the one or more pairs of color Doppler values.

21. A system according to claim 19, wherein determination of the configuration of flow areas comprises:

determination of whether the color Doppler data includes single-inclusions, double-inclusions or triple-inclusions.

22. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of no aliasing corrections for the color Doppler data if the normalized energy function across one or more transitions is less than a preset threshold.

23. A system according to claim 22, wherein the preset threshold is a velocity corresponding to the Doppler shift frequency of half a pulse repetition frequency associated with the color Doppler data.

24. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of single aliasing correction for the color Doppler data of a flow area in contact with a transition if the normalized energy function across the transition is greater than a preset threshold.

25. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of no aliasing correction for the color Doppler data of a flow area in contact with a zero velocity area.

26. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of single aliasing correction for the color Doppler data of a flow area which is in contact with a zero flow area, and in contact with a transition with an opposite flow velocity area, wherein the normalized energy function across the transition is greater than a preset threshold.

27. A system according to claim 26, wherein the flow area for which single aliasing correction is determined is smaller than the opposite flow velocity area.

28. A system according to claim 26, wherein determination of single aliasing correction comprises:

calculation of a first total energy function of the color Doppler data based on single aliasing correction applied to one of the two flow areas (area A) and no aliasing corrections applied to the other one of the two flow areas (area B);

calculation of a second total energy function of the color Doppler data based on single aliasing correction applied to area B and no aliasing corrections applied to area A; and

determination of a smaller of the first and second total energy functions.

29. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of single aliasing correction for the color Doppler data of a flow area representing flow velocity in a first direction which is surrounded by a second flow area representing flow velocity in a second direction which is in contact with a zero velocity area; and

determination of no aliasing correction for the color Doppler data of the second flow area.

30. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of single aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by a second flow area representing flow velocity in a second direction which is in contact with a zero velocity area; and

determination of no aliasing correction for the color Doppler data of the second flow area if the normalized energy function across a transition between the first flow area and the second flow area is greater than a preset threshold.

31. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of double aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is in turn surrounded by and in contact with a third flow area representing flow velocity in the first flow direction which is surrounded by and in contact with a zero velocity area;

determination of single aliasing correction for the color Doppler data of the second flow area; and

determination of no aliasing correction for the color Doppler data of the third flow area.

32. A system according to claim 19, wherein, determination of the aliasing corrections comprises:

determination of double aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is in turn surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a zero velocity area;

determination of single aliasing correction for the color Doppler data of the second flow area; and

determination of no aliasing correction for the color Doppler data of the third flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is less than a first preset threshold and if the normalized energy function across a transition between the second flow area and the third flow area is greater than a second preset threshold.

33. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of no aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a zero velocity area;

determination of single aliasing correction for the color Doppler data of the second flow area; and

determination of no aliasing correction for the color Doppler data of the third flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is greater than a first preset threshold and if the normalized energy function across a transition between the second flow area and third flow area is greater than a second preset threshold.

34. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of triple aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a fourth flow area which is surrounded by and in contact with a zero velocity area;

determination of double aliasing correction for the color Doppler data of the second flow area;

determination of single aliasing correction for the color Doppler data of the third flow area; and

determination of no aliasing correction for the color Doppler data of the fourth flow area.

35. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of triple aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first direction which is surrounded by and in contact with a fourth flow area which is surrounded by and in contact with a zero velocity area;

determination of double aliasing correction for the color Doppler data of the second flow area;

determination of single aliasing correction for the color Doppler data of the third flow area; and

determination of no aliasing correction for the color Doppler data of the fourth flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is greater than a preset threshold, if the normalized energy function across a transition between the second flow area and the third flow area is less than a second preset threshold, and if the normalized energy function across a transition between the third flow area and the fourth flow area is greater than a third preset threshold.

36. A system according to claim 19, wherein determination of the aliasing corrections comprises:

determination of single aliasing correction for the color Doppler data of a first flow area representing flow velocity in a first direction which is surrounded by and in contact with a second flow area representing flow velocity in a second direction which is surrounded by and in contact with a third flow area representing flow velocity in the first flow direction which is surrounded by and in contact with a fourth flow area representing flow velocity in the second flow direction which is surrounded by and in contact with a zero velocity area;

determination of double aliasing correction for the color Doppler data of the second flow area;

determination of single aliasing correction for the color Doppler data of the third flow area; and

determination of no aliasing correction for the color Doppler data of the fourth flow area,

if the normalized energy function across a transition between the first flow area and the second flow area is less than a preset threshold, if the normalized energy function across a transition between the second flow area and the third flow area is less than a second preset threshold, and if the normalized energy function across a transition between the third flow area and the fourth flow area is greater than a third preset threshold.