System and method for 3-D visualization of vascular structures using ultrasound

• US 20060241461A1
• Filed: 03/31/2006
• Published: 10/26/2006
• Est. Priority Date: 04/01/2005
• Status: Abandoned Application

• Current Assignee: VisualSonics Inc. (Fujifilm Holdings Corporation)
• Original Assignee: VisualSonics Inc. (Fujifilm Holdings Corporation)
• Inventors: Mehi, James I., Hirson, Desmond, White, Chris A.
• Application Number:
  US11/395,534
• Publication Number:
  US 20060241461A1
• Time in Patent Office: Days
• US Class Current: 600/454
• CPC Class Codes: A61B 2503/40 Animals
• CPC Class Codes: A61B 5/1075 for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer A61B8/0858 takes precedence
• 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 8/13 Tomography A61B8/10, A61B8/12 take precedence; tomography for radiation diagnosis A61B6/02
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61B 8/543 involving acquisition triggered by a physiological signal
• CPC Class Codes: G01S 15/8979 Combined Doppler and pulse-echo imaging systems
• CPC Class Codes: G01S 15/8988 Colour Doppler imaging
• CPC Class Codes: G01S 15/8993 Three dimensional imaging systems

Abstract

A method for quantifying vascularity of a structure or a portion thereof comprises producing a plurality of two dimensional (2-D) high-frequency ultrasound image slices through at least a portion of the structure, wherein the structure or portion thereof is located within a subject, processing at least two of the plurality of 2-D ultrasound image slices to produce a three dimensional (3-D) volume image and quantifying the vascularity of the structure or portion thereof.

Claims

1. A method for determining the percentage vascularity of a vascular structure or portion thereof, comprising:

determining the total volume (TV_s) and the total volume of vascularity (TV_vas) of the structure or portion thereof using ultrasound imaging; and

determining the ratio of TV_vas to TV_s, wherein the ratio of TV_vas to TV_s provides the percentage vascularity of the structure or portion thereof.

2. The method of claim 1, wherein the TV_s of the structure or portion thereof is determined by:

producing a plurality of two dimensional ultrasound slices taken through the structure or portion thereof, each slice being taken at location along an axis substantially perpendicular to the plane of the slice and each slice being separated by a known distance along the axis;

capturing B-mode data at each slice location;

reconstructing a three dimensional volume of the structure or portion thereof from the B-mode data captured at two or more slice locations; and

determining the TV, from the reconstructed three dimensional volume.

3. The method of claim 2, wherein the TV_vas of the structure or portion thereof is determined by:

capturing Doppler data at each slice location, the Doppler data representing blood flow within the structure or portion thereof,

quantifying the number of voxels within the reconstructed three dimensional volume that comprise captured Doppler data and multiplying the number of voxels comprising Doppler data by the volume of a voxel to determine the TV_vas.

4. The method of claim 2, wherein the TV_vas of the structure or portion thereof is determined by:

capturing Doppler data at each slice location, the Doppler data representing blood flow within the structure or portion thereof,

quantifying the number of voxels within the reconstructed three dimensional volume that do not comprise captured Doppler data;

multiplying the number of voxels not comprising Doppler data by the volume of a voxel; and

subtracting the determined multiple from the determined TV_s to determine the TV_vas.

5. The method of claim 3, wherein each voxel that has a measured power that is less than a predetermined threshold value is disregarded in the calculation of TV_vas.

6. The method of claims 3 or 4, further comprising determining the total power of the blood flow within the structure or portion thereof.

7. The method of claim 6, wherein the total power of the blood flow within the structure or portion thereof is determined by the summation of the product of the Power Doppler value of each voxel with a parameter K_v, wherein K_v provides a correction factor for depth dependent signal variation.

8. The method of claim 7, wherein each voxel that has a measured power that is less than a predetermined threshold value is disregarded.

9. The method of claim 3, wherein the captured Doppler data is Power Doppler data.

10. The method of claim 3, wherein the captured Doppler data is Color flow Doppler data.

11. The method of claim 3, wherein the structure is located within a subject.

12. The method of claim 11, wherein the captured Doppler data and the B-mode data are produced using ultrasound transmitted into the subject or portion thereof at a frequency of 20 MHz or higher.

13. The method of claim 11, wherein the subject is a small animal.

14. The method of claim 13, wherein the small animal is selected from the group consisting of a mouse, rat, and rabbit.

15. The method of claim 11, wherein the structure is a tumor.

16. The method of claim 3, wherein each location along the axis corresponds to a predefined area of a portion of the subject'"'"'s anatomy where the B-mode data and Doppler data is captured from the subject.

17. The method of claim 3, wherein the structure is located within a subject and wherein the B-mode data and the Doppler data are captured when the subject'"'"'s movement due to breathing has substantially stopped.

18. The method of claim 17, further comprising:

monitoring a respiration waveform of a subject and detecting a peak period in the waveform, wherein the peak corresponds to a time when the subject'"'"'s bodily motion caused by its respiration has substantially stopped;

capturing the B-mode data and Doppler data from the subject, wherein the capturing is performed during the waveform peak period corresponding to the time when the subject'"'"'s bodily motion caused by its respiration has substantially stopped.

19. The method of claim 18, further comprising, prior to the step of capturing the B-mode data and Doppler data from the subject,

generating ultrasound at a frequency of at least 20 megahertz (MHz);

and

transmitting ultrasound at a frequency of at least 20 MHz into the subject, wherein the steps of generating, transmitting and capturing are performed during the waveform peak period corresponding to the time when the subject'"'"'s bodily motion caused by its respiration has substantially stopped.

20. The method of claim 19, wherein the steps of generating, transmitting and capturing are incrementally repeated at each location along the axis to capture the B-mode data and the Doppler data.

21. The method of claim 17, further comprising:

monitoring a respiration waveform of a subject and detecting at least one peak period in the respiration waveform, each peak period corresponding to a time when the subject'"'"'s bodily motion caused by its respiration has substantially stopped, and at least one non-peak period of the respiration waveform, each non-peak period corresponding to a time when the subject'"'"'s body is in motion due to its respiration;

generating ultrasound at a frequency of at least 20 megahertz (MHz);

transmitting ultrasound at a frequency of at least 20 MHz into a subject;

capturing the B-mode data and Doppler data from the subject during the least one peak period of the subject'"'"'s respiration waveform and during the at least one non-peak period of the subject'"'"'s respiration waveform, wherein the steps of generating, transmitting and capturing are incrementally repeated at each location along the axis;

compiling the captured ultrasound data at each slice location to form an initial data frame comprising a B-mode data and Doppler data;

identifying at least one portion of the initial data frame comprising data received during a non-peak period of the subject'"'"'s respiration waveform;

processing the initial data frame to produce a final data frame for each slice location, wherein the final data frame is compiled from B-mode and Doppler data received during the incremental peak periods of the subject'"'"'s respiration waveform; and

reconstructing the three dimensional volume from a plurality of final data frames.

22. The method of claim 21, wherein the processing step comprises:

removing data from the initial data frame that was received during non-peak periods of the subject'"'"'s respiration waveform at location along the axis to produce a partially blanked out data frame having at least one blanked out region; and

substituting data received during the peak of the subject'"'"'s respiration waveform from at least one other initial data frame taken at the same location along the axis into the at least one blanked out region of the partially blanked out image to produce the final date frame.

23. The method of claim 22, wherein the substituted data received during the peak of the subject'"'"'s respiration waveform is from a region of its data frame that spatially corresponds to the blanked out region of the partially blanked out region of the partially blanked out image.

24. A system for determining the percentage vascularity of a vascular structure or portion thereof, comprising:

a transducer for generating ultrasound at a frequency of at least 20 MHz, for transmitting at least a portion of the generated ultrasound into the vascular structure or portion thereof, and for capturing ultrasound energy; and

a processor for determining the total volume (TV_s) and the total volume of vascularity (TV_vas) of the structure or portion thereof from the captured ultrasound energy and for determining the ratio of TV_vas to TV_s, wherein the ratio of TV_vas to TV_s provides the percentage vascularity of the structure or portion thereof.

25. The system of claim 24, further comprising means for monitoring a respiration waveform of a subject and for detecting a peak period in the waveform, wherein the peak corresponds to a time when the subject'"'"'s bodily motion caused by its respiration has substantially stopped.

26. The system of claim 24, wherein the processor is configured for determining the total power of the blood flow within the vascular structure or portion thereof.