Methods and apparatus for using ultrasound with contrast agent

• US 6,547,738 B2
• Filed: 05/03/2001
• Issued: 04/15/2003
• Est. Priority Date: 05/03/2001
• Status: Expired due to Term

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Lysyansky, Peter
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): Jung, William C
• Application Number:
  US09/681,589
• Publication Number:
  US 20020165455A1
• Time in Patent Office: 712 Days
• Field of Search: 600/437-472
• US Class Current: 600/458
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• 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 8/0883 for diagnosis of the heart
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52039 exploiting the non-linear response of a contrast enhancer, e.g. a contrast agent diagnostic techniques involving the use of contrast agents A61B8/481
• CPC Class Codes: G01S 7/52085 Details related to the ultrasound signal acquisition, e.g. scan sequences control of medical diagnostic ultrasound devices A61B8/54

Abstract

Methods and apparatus for producing zones with different contrast agent concentrations in a contrast agent infused target. An aspect of the method is subjecting the target to an ultrasound flash capable of producing first and second target zones, the first target zone having a higher concentration of contrast agent than the second target zone. Another aspect of the method is forming an ultrasound image of the target, wherein the first and second target zones in the ultrasound image have different ultrasonic responses. An embodiment of the apparatus of the present invention comprises a front-end controller (FEC) for use in a medical imaging system wherein the FEC controls a transducer to selectively radiate, in a single frame, a first beam position at a first energy and a second beam position at a second energy.

Claims

1. A method for detecting movement of contrast agent infused heart tissue, the method comprising the steps of:

subjecting the heart tissue to an ultrasound flash capable of producing a plurality of first and second target zones, the first and second target zones being stripes, the first target zones having a higher concentration of contrast agent than the second target zones;

forming an ultrasound image of the heart tissue, wherein the first target zones appear brighter than the second target zones in the ultrasound image; and

measuring, over time, a width of at least one of the stripes to detect movement of the heart tissue.

2. The method of claim 1 wherein the step of measuring a width of at least one of the stripes over time is performed to measure an amount of heart relaxation or contraction.

3. The method of claim 1, the measuring step further comprising:

measuring a first width of said at least one of the stripes when the heart is in a relaxed state;

measuring a second width of said at least one of the stripes when the heart is in a contracted state; and

calculating a contractility of the heart based upon the first and second widths.

4. The method of claim 1, the measuring step further comprising:

measuring a first width of said at least one of the stripes when the heart is in a relaxed state;

measuring a second width of said at least one of the stripes when the heart is in a contracted state; and

calculating a change in width between said first and second widths, said change in width representing a contractility of the heart tissue represented by said at least one of the stripes.

5. A method for producing an ultrasound image of a contrast agent infused target, the method comprising the steps of:

subjecting the target to an ultrasound flash capable of producing a plurality of first and second target zones, the first and second target zones being stripes, the first target zones having a higher concentration of contrast agent than the second target zones;

forming an ultrasound image of the target, wherein the first target zones appear brighter than the second target zones in the ultrasound image; and

comparing, over time, a brightness of at least one of the second target zones with a brightness of at least one of the first target zones.

6. A method for producing an ultrasound image of a contrast agent infused target, the method comprising the steps of:

subjecting the target to an ultrasound flash capable of producing a plurality of first and second target zones, the first and second target zones being stripes, the first target zones having a higher concentration of contrast agent than the second target zones;

forming an ultrasound image of the target, wherein the first target zones appear substantially brighter than the second target zones in the ultrasound image;

comparing, over time, a brightness of at least one of the second target zones with a brightness of at least one neighboring first target zone; and

measuring an amount of time that elapses from the step of subjecting the target to an ultrasound flash to a time when a ratio between the brightness of the at least one of the second target zones and the brightness of the at least one neighboring first target zone reaches a pre-determined value.

7. The method of claim 6 wherein the target comprises heart tissue.

8. The method of claim 6 further comprising measuring a width of at least one of the stripes over time to detect movement of heart tissue.

9. An ultrasound imaging system for calculating blood perfusion in tissue, the system including:

a keyboard for selecting first and second energies used to radiate contrast agent infused tissue for a first predetermined amount of time and for selecting a third energy used to radiate the tissue for a second predetermined amount of time, said first and third energies destroying a relatively small amount of contrast agent and said second energy destroying a relatively large amount of contrast agent;

a front-end controller (FEC) controlling a transducer to radiate, within said first period of time, a plurality of first beam positions forming first transmission regions at said first energy and a plurality of second beam positions forming second transmission regions at said second energy, said FEC radiating the tissue with said third energy for said second predetermined amount of time; and

a display for displaying the tissue while the FEC is radiating the tissue with the third energy, said keyboard selecting first and second points within the first and second transmission regions, respectively, said first and second points being used to calculate brightness values for each of said first and second transmission regions, said brightness values representing a perfusion rate of the tissue.

10. The ultrasound system of claim 9, said keyboard setting said first energy to be zero energy.

11. The ultrasound system of claim 9, said FEC forming the first and second transmission regions with an unequal number of beam positions.

12. The ultrasound system of claim 9, said FEC forming each of the first and second transmission regions with 2 to 10 beams.

13. The ultrasound system of claim 9, said FEC forming each of the first and second transmission regions 4 to 6 beams.

14. The ultrasound system of claim 9, said FEC shaping the first transmission region to create a stripe-shaped first target zone and shaping the second transmission region to create a stripe-shaped second target zone.

15. A method for determining a perfusion rate of contrast agent infused tissue, the method comprising:

subjecting contrast agent infused tissue to an ultrasound flash capable of producing a plurality of first and second target zones, said ultrasound flash destroying a first percentage of contrast agent in said first target zones and a second percentage of contrast agent in said second target zones, said second percentage being greater than said first percentage;

acquiring consecutive image frames comprising said first and second target zones, at least one second target zone being substantially brighter than at least one first target zone;

measuring a brightness of said at least one first target zone for each image frame;

measuring a brightness of said at least one second target zone for said each image frame;

comparing, over time, a brightness of said at least one second target zone with a brightness of at least one first target zone to determine a rate of perfusion of said at least one second target zone; and

determining a perfusion rate for the tissue based on a ratio of said brightnesses for said each image frame.

16. The method of claim 15, further comprising measuring an amount of elapsed time from the step of subjecting the tissue to said ultrasound flash to a time when said second target zones have substantially the same brightness as said first target zones.

17. The method of claim 15, wherein said first percentage of contrast agent in said first target zones is equal to zero.

18. The method of claim 15, further comprising measuring a rate at which said at least one second target zone increases in brightness.

19. The method of claim 15, said at least one first and second target zones being adjacent.

20. The method of claim 15, said at least one first and second target zones being not adjacent to one another.

21. A method for estimating blood perfusion of tissue, the method comprising:

transmitting first and second ultrasound transmissions within one frame, said first ultrasound transmission being transmitted in at least one first region of tissue and said second ultrasound transmission being transmitted in at least one second region of tissue, said at least one first and second regions of tissue being continuously infused with a contrast agent, said first ultrasound transmission destroying a first percentage of the contrast agent in said at least one first region, said second ultrasound transmission destroying a second percentage of the contrast agent in said at least one second region, said first percentage being greater than said second percentage;

acquiring consecutive image frames comprising said first and second regions of tissue, said first and second regions displaying different ultrasonic responses;

measuring said ultrasound response of said first regions of tissue for each, image frame;

measuring said ultrasound response of said second regions of tissue for said each image frame;

measuring an amount of time that elapses from the transmitting step to a time when an ultrasound response of said second regions is substantially the same as an ultrasound response of said first regions; and

determining a perfusion rate for the tissue based on a ratio of said ultrasound responses for said each image frame.

22. The method of claim 21 and comprising the step of:

comparing, over time, the ultrasound response of at least one of the first regions of tissue with the ultrasound response of at least one of the second regions of tissue.

23. The method of claim 21, wherein a number of said first ultrasound transmissions being different from said second ultrasound transmissions is said one frame.

24. A method for identifying an interface between tissue and blood within a contrast agent infused target, the method comprising the steps of:

subjecting a target comprising tissue and blood to an ultrasound flash capable of forming a pattern of acoustic markers, said pattern comprising a plurality of first and second target zones with substantially different brightness levels, said ultrasound flash destroying a first percentage of contrast agent in said first target zones and a second percentage of contrast agent in said second target zones, the first and second percentages being substantially different to produce said first and second target zones;

forming an ultrasound image of the target; and

identifying an interface between the tissue and blood based on said pattern of acoustic markers, said pattern of acoustic markers being absent from target zones being produced in areas of the target comprising blood, said pattern of acoustic markers being present in target zones being produced in areas of the target comprising tissue.

25. The method of claim 24, the identifying step further comprising:

calculating, for each target zone, an amount of time required for said each target zone to become substantially the same brightness;

identifying said first and second target zones being produced in the areas of the target comprising blood, said first and second target zones produced in the areas of the target comprising blood being adjacent and having relatively low said amounts of time; and

identifying an interfacing target zone, said interfacing target zone having a relatively high said amount of time and being adjacent to a single target zone produced in the areas of the target comprising blood.

26. An ultrasound imaging system for detecting motion in tissue, the system including:

a keyboard for selecting first and second energies used to radiate contrast agent infused tissue for a first predetermined amount of time and for selecting a third energy used to radiate the tissue for a second predetermined amount of time, said first and third energies destroying a relatively small amount of contrast agent and said second energy destroying a relatively large amount of contrast agent;

a front-end controller (FEC) controlling a transducer to radiate, within said first period of time, a plurality of first beam positions forming first transmission regions at said first energy and a plurality of beam positions forming second transmission regions at said second energy, said FEC radiating said first and second transmission regions with said third energy for said second predetermined amount of time; and

a display for displaying said first and second transmission regions while the FEC is radiating said first and second transmission regions with the third energy, said keyboard measuring a width of at least one second transmission region over time to detect movement of the tissue.

27. The method of claim 26, further comprising said FEC controlling said transducer to radiate the tissue repeatedly with a sequence comprising said first and second periods of time.

28. The method of claim 26, further comprising:

said FEC controlling said transducer to radiate heart tissue repeatedly with a sequence comprising said first and second periods of time; and

said keyboard measuring a width of at least one second transmission region when the heart is at a peak of contraction and when the heart is at a peak of relaxation.