QUANTITATIVE ASSESSMENT OF NEOVASCULARIZATION

• US 20130204127A1
• Filed: 01/30/2013
• Published: 08/08/2013
• Est. Priority Date: 01/30/2012
• Status: Active Grant

• Current Assignee: TECHNION RESEARCH AND DEVELOPMENT FOUNDATION, LTD.
• Original Assignee: TECHNION RESEARCH AND DEVELOPMENT FOUNDATION, LTD.
• Inventors: HOOGI, ASSAF, BAR-ZION, AVINOAM, ADAM, DAN
• Granted Patent: US 9,216,008 B2
• Time in Patent Office: Days
• US Class Current: 600/431
• 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 8/085 for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules
• CPC Class Codes: A61B 8/0891 for diagnosis of blood vessels
• 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 8/5207 involving processing of raw data to produce diagnostic data, e.g. for generating an image reconstruction G06T11/00
• CPC Class Codes: A61B 8/5276 due to motion
• CPC Class Codes: G06T 2207/10132 Ultrasound image
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 2207/30096 Tumor; Lesion
• CPC Class Codes: G06T 2207/30101 Blood vessel; Artery; Vein; Vascular
• CPC Class Codes: G06T 7/0012 Biomedical image inspection

Abstract

Systems and methods using contrast enhanced ultrasound imaging for quantitative assessment of neovascularization, such as within a tumor or a plaque. The contrast agent moves in small blotches rather than in continuous flow, but image processing methods enable the detection and quantification of the blood flow, even in the tiny blood vessels of the vasculature tree. The image processing includes compensation for motion of the tissue arising from body movement. The position and extent of the discrete positions of contrast material may be accumulating during a complete heart cycle onto a single 2D image, to enable an indication of a vascular tree based on this local accumulated image. Dynamic processing (DP) of the discrete positions of contrast material enables a complete vascular tree to be obtained. The neovascularization is quantified by the ratio of its total area to that of the plaque in which the neovascularization has grown.

Claims

1. A method of analyzing ultrasound images to provide information regarding neovascularization in a tissue of a subject, said method comprising:

obtaining a series of contrast enhanced ultrasound images of said tissue;

compensating for motion of tissue features between different ones of said contrast enhanced ultrasound images, to generate a series of compensated images;

detecting in at least one of said compensated images discrete segments of imaged contrast material;

constructing a representation of an arterial tree from said detected segments; and

quantifying the level of the neovascularization from the extent of the detected segments in said representation of said arterial tree.

2. A method according to claim 1, wherein said representation of said arterial tree is constructed by superimposing the positions of said discrete segments of said imaged contrast material from at least two sequential ones of said compensated images, to generate an accumulated image, and detecting segments on said accumulated image.

3. A method according to claim 1, wherein said representation of said arterial tree is constructed by performing dynamic programming on at least one of said series of compensated images.

4. A method according to claim 2, wherein said representation of said arterial tree is constructed by performing dynamic programming on said accumulated image.

5. A method according to claim 1, wherein said arterial tree comprises at least one continuous path between said discrete segments.

6. A method according to claim 1, wherein said quantifying is performed by determining the ratio of the extent of said detected segments in said arterial tree to the imaged area of the tissue in which said neovascularization is to be determined.

7. A method according to claim 1, wherein said compensating for motion of features between different ones of said images is performed by either one of forward tracking or particle filtering methods.

8. A method according to claim 7, wherein said forward tracking method utilizes template matching with a normalized cross correlation criterion.

9. A method according to claim 7, wherein said particle filtering method utilizes a Sum of Absolute Differences (SAD) criterion for each particle.

10. A method according to claim 1, wherein said motion of tissue features comprises at least one of translation, rotation and change of scale of said features.

11. A method according to claim 1, wherein said tissue is either of a plaque or a tumor.

12. A system for providing information regarding neovascularization in a tissue of a subject, said system comprising:

an ultrasound system for generating a series of contrast enhanced ultrasound images of said tissue;

a frame analysis unit receiving said images and adapted to designate locations within said images showing the presence of contrast material;

a motion compensating unit, configured to output a series of compensated images in which the effects of motion of imaged features of said tissue between different ones of said images is cancelled;

an image processing system comprising;

a segment detector unit, adapted to detect in at least one of said compensated images discrete segments of imaged contrast material; and

an arterial tree constructor for outputting a representation of an arterial tree from said detected segments; and

an output unit using the extent of said detected segments in said representation of said arterial tree to quantify the level of neovascularization in said tissue.

13. A system according to claim 12, wherein said arterial tree constructor is configured to superimpose the positions of discrete segments of said imaged contrast material from at least two sequential ones of said compensated images, to generate an accumulated image, and to detect segments on said accumulated image.

14. A system according to claim 12, wherein said arterial tree constructor is configured to perform dynamic programming on at least one of said series of compensated images.

15. A system according to claim 13, wherein said arterial tree constructor is configured to perform dynamic programming on said accumulated image.

16. A system according to claim 12, wherein said arterial tree comprises at least one continuous path between said discrete segments.

17. A system according to claim 12, wherein said output unit is adapted to quantify the level of neovascularization in said tissue by determining the ratio of the extent of said detected segments in said arterial tree to the imaged area of the tissue in which said neovascularization is to be quantified.

18. A system according to claim 12, wherein said motion compensating unit is adapted to perform either one of forward tracking or particle filtering methods.

19. A system according to claim 18, wherein said forward tracking method utilizes template matching with a normalized cross correlation criterion.

20. A system according to claim 18, wherein said particle filtering method utilizes a Sum of Absolute Differences (SAD) criterion for each particle.

21. A system according to claim 12, wherein said motion of imaged features of said tissue comprises at least one of translation, rotation and change of scale of said features.

22. A system according to claim 12, wherein said tissue is either of a plaque or a tumor.