Method and apparatus for three-dimensional reconstruction of coronary vessels from angiographic images and analytical techniques applied thereto

• US 6,501,848 B1
• Filed: 11/20/1999
• Issued: 12/31/2002
• Est. Priority Date: 06/19/1996
• Status: Expired due to Term

• Current Assignee: University Technology Corporation
• Original Assignee: University Technology Corporation
• Inventors: Carroll, John, Chen, Shiuh-Yung James
• Primary Examiner(s): Patel, Jayanti K.
• Application Number:
  US09/444,138
• Time in Patent Office: 1,137 Days
• Field of Search: 382/100, 382/128-134, 382/262, 382/285, 378/4, 378/901, 378/9, 378/8, 128/623.1, 434/272, 600/483
• US Class Current: 382/128
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/404 Angiography

Abstract

A method for in-room computer reconstruction of a three-dimensional (3-D) coronary vascular tree from routine biplane angiograms acquired at arbitrary angles and without using calibration objects. The method includes seven major steps: (1) acquisition of two standard angiogram sequences by use of a single-plane or biplane imaging system, (2) identification of 2-D coronary vascular trees and feature extractions including bifurcation points, directional vectors, vessel centerlines, and construction of vessel hierarchy in the two images, (3) determination of transformation in terms of a rotation matrix R and a translation vector {right arrow over (t)} based on the extracted vessel bifurcation points and directional vectors, (4) establishment of vessel centerline correspondence, (5) calculation of the skeleton of 3-D coronary vascular trees, (6) rendering of 3-D coronary vascular tree with associated gantry angulation, and (7) calculation of optimal view(s) and 3-D QCA as quantitative measures associated with the selected vascular segment(s) of interest. The calculation of optimal views includes determination of 2-D projections of the reconstructed 3-D vascular tree so as to minimize foreshortening of a selected vascular segment, overlap of a selected vascular segment or both overlap and foreshortening of a selected arterial segment.

Claims

1. A method for three-dimensional reconstruction of a target object from two-dimensional images, said target object having a plurality of branch-like vessels, the method comprising the steps of:

a) placing the target object in a position to be scanned by an imaging system, said imaging system having a plurality of imaging portions;

b) acquiring a plurality of projection images of the target object, each imaging portion providing a projection image of the target object, each imaging portion disposed at an unknown orientation relative to the other imaging portions;

c) identifying two-dimensional vessel centerlines for a predetermined number of the vessels in each of the projection images;

d) creating a vessel hierarchy data structure for each projection image, said data structure including the identified two-dimensional vessel centerlines defined by a plurality of data points in the vessel hierarchy data structure;

e) calculating a predetermined number of bifurcation points and directional vectors for each projection image by traversing the corresponding vessel hierarchy data structure, said bifurcation points defined by intersections of the two-dimensional vessel centerlines and said directional vectors defined by tangent vectors on said bifurcation points;

f) determining a transformation in the form of a rotation matrix and a translation vector utilizing the bifurcation points and the directional vectors corresponding to each of the projections images, said rotation matrix and said translation vector representing imaging parameters corresponding to the orientation of each imaging portion relative to the other imaging portions of the imaging system;

g) utilizing the data points and the transformation to establish a correspondence between the two-dimensional vessel centerlines corresponding to each of the projection images such that each data point corresponding to one projection image is linked to a data point corresponding to the other projection images, said linked data points representing an identical location in the vessel of the target object;

h) calculating three-dimensional vessel centerlines utilizing the two-dimensional vessel centerlines and the correspondence between the data points of the two-dimensional vessel centerlines; and

i) reconstructing a three-dimensional visual representation of the target object based on the three-dimensional vessel centerlines and diameters of each vessel estimated along the three-dimensional centerline of each vessel.

2. The method of claim 1 wherein the step of identifying vessel centerlines includes the step of:

identifying two-dimensional vessel centerlines for a predetermined number of landmarks in each of the projection images.

3. The method of claim 1 wherein the step of utilizing the data points and the transformation to establish a correspondence comprises the step of:

utilizing the data points and the transformation to establish local and global correspondences between the two-dimensional vessel centerlines corresponding to each of the projection images such that each data point corresponding to one projection image is linked to a data point corresponding to the other projection images, said linked data points representing an identical location in the vessel of the target object.

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

identifying a predetermined number of landmarks in each of the projection images wherein said landmarks are man-made objects identified in the projection images,

wherein the step of determining said transformation comprises the step of;

f) determining a transformation in the form of a rotation matrix and a translation vector utilizing the landmarks and utilizing the bifurcation points and utilizing the directional vectors corresponding to each of the projections images, said rotation matrix and said translation vector representing imaging parameters corresponding to the orientation of each imaging portion relative to the other imaging portions of the imaging system.

5. The method of claim 1 further comprising the step of:

identifying a predetermined number of landmarks in each of the projection images wherein said landmarks are points and curves identified in the projection images,

wherein the step of determining said transformation comprises the step of;

f) determining a transformation in the form of a rotation matrix and a translation vector utilizing the landmarks and utilizing the bifurcation points and utilizing the directional vectors corresponding to each of the projections images, said rotation matrix and said translation vector representing imaging parameters corresponding to the orientation of each imaging portion relative to the other imaging portions of the imaging system.

6. A method for quantitative analysis of a vascular tree comprising the steps of:

providing a 3-D vessel hierarchy data structure describing the vascular tree;

displaying a 2-D projection of said 3-D vessel hierarchy data structure on a user'"'"'s display screen;

receiving input from the user to select a desired segment of said vascular tree wherein said selected segment includes any number of contiguous segments forming a sub-tree of said vascular tree;

receiving input from the user to select a desired quantitative measure of said selected segment wherein said desired quantitative measure is a value determinable from data derived from said 3-D vessel hierarchy data structure;

calculating said quantitative measure using said data derived from said 3-D vessel hierarchy; and

displaying said quantitative measure on the users display screen.

7. The method of claim 6 further comprising the steps of:

receiving input from the user to select an alternate viewing angle of said vascular tree;

computing an updated 2-D projection of said 3-D vessel hierarchy data structure based on said alternate viewing angle; and

displaying said updated 2-D projection on the user'"'"'s display screen.

8. The method of claim 6

wherein the step of receiving input from the user to select said desired quantitative measure includes the step of receiving user input to evaluate a take-off angle of said selected segment, and

wherein the step of calculating includes the step of calculating said take-off angle.

9. The method of claim 8 wherein the step of calculating said take-off angle comprises the step of:

calculating said take-off angle of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having two degrees of freedom.

10. The method of claim 8 wherein the step of calculating said take-off angle comprises the step of:

calculating said take-off angle of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having three degrees of freedom.

11. The method of claim 6

wherein the step of receiving input from the user to select said desired quantitative measure includes the step of receiving user input to evaluate an insertion angle of said selected segment, and

wherein the step of calculating includes the step of calculating said insertion angle.

12. The method of claim 6

wherein the step of receiving input from the user to select said desired quantitative measure includes the step of receiving user input to evaluate a length of said selected segment, and

wherein the step of calculating includes the step of calculating said length.

13. The method of claim 6

wherein the step of receiving input from the user to select said desired quantitative measure includes the step of receiving user input to evaluate tortuosity of said selected segment, and

wherein the step of calculating includes the step of calculating said tortuosity.

14. The method of claim 13 wherein the step of calculating said tortuosity comprises the step of:

calculating said tortuosity in accordance with the F-S theory.

15. The method of claim 13 wherein the step of calculating said tortuosity comprises the step of:

calculating said tortuosity in accordance with the Point-to-Point method.

16. The method of claim 6 wherein the step of receiving input from the user to select said desired quantitative measure includes the step of receiving user input to determine an optimal viewing angle of said selected segment relative to said desired quantitative measure.

17. The method of claim 16

wherein the step of receiving input from the user to select said desired quantitative measure further includes the step of receiving user input to determine said optimal viewing angle relative to foreshortening of said selected segment, and

wherein the step of calculating comprises the step of calculating foreshortening of said selected segments for all possible viewing angles, and

wherein the method further comprises the steps of:

determining said optimal viewing angle from said all possible viewing angles so as to minimize said foreshortening;

computing an updated 2-D projection of said 3-D vessel hierarchy data structure based on said optimal viewing angle; and

displaying said updated 2-D projection on the user'"'"'s display screen.

18. The method of claim 17 wherein the step of calculating said foreshortening comprises the step of:

calculating said foreshortening of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having two degrees of freedom.

19. The method of claim 17 wherein the step of calculating said foreshortening comprises the step of:

calculating said foreshortening of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having three degrees of freedom.

20. The method of claim 17 wherein the step of determining said optimal view comprises the step of:

displaying a color coded map having a plurality of points on the user'"'"'s display screen wherein the color of each said point indicates the magnitude of said foreshortening at a corresponding viewing angle;

receiving input from the user to select a desired to select a point of said plurality of points; and

determining said optimal viewing angle as the viewing angle corresponding to the selected point.

21. The method of claim 16

wherein the step of receiving input from the user to select said desired quantitative measure further includes the step of receiving user input to determine said optimal viewing angle relative to overlap of said selected segment, and

wherein the step of calculating comprises the step of calculating overlap of said selected segments for all possible viewing angles, and

wherein the method further comprises the steps of:

determining said optimal viewing angle from said all possible viewing angles so as to minimize said overlap;

computing an updated 2-D projection of said 3-D vessel hierarchy data structure based on said optimal viewing angle; and

displaying said updated 2-D projection on the user'"'"'s display screen.

22. The method of claim 21 wherein the step of calculating said overlap comprises the step of:

calculating said overlap of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having two degrees of freedom.

23. The method of claim 21 wherein the step of calculating said overlap comprises the step of:

calculating said overlap of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having three degrees of freedom.

24. The method of claim 21 wherein the step of determining said optimal view comprises the step of:

displaying a color coded map having a plurality of points on the user'"'"'s display screen wherein the color of each said point indicates the magnitude of said overlap at a corresponding viewing angle;

receiving input from the user to select a desired to select a point of said plurality of points; and

determining said optimal viewing angle as the viewing angle corresponding to the selected point.

25. The method of claim 16

wherein the step of receiving input from the user to select said desired quantitative measure further includes the step of receiving user input to determine said optimal viewing angle relative to a combination of foreshortening and overlap of said selected segment, and

wherein the step of calculating comprises the steps of:

calculating overlap of said selected segments for all possible viewing angles; and

calculating foreshortening of said selected segments for all possible viewing angles, and

wherein the method further comprises the steps of;

determining said optimal viewing angle from said all possible viewing angles so as to minimize the combination of said overlap and said foreshortening;

computing an updated 2-D projection of said 3-D vessel hierarchy data structure based on said optimal viewing angle; and

displaying said updated 2-D projection on the user'"'"'s display screen.

26. The method of claim 25

wherein the step of calculating said overlap comprises the step of:

calculating said overlap of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having two degrees of freedom, and

wherein the step of calculating said foreshortening comprises the step of;

calculating said foreshortening of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having two degrees of freedom.

27. The method of claim 25

wherein the step of calculating said overlap comprises the step of:

calculating said overlap of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having three degrees of freedom, and

wherein the step of calculating said foreshortening comprises the step of;

calculating said foreshortening of said selected segment wherein said 3-D vessel hierarchy is reconstructed using data generated by an imaging system having three degrees of freedom.

28. The method of claim 25 wherein the step of determining said optimal view comprises the step of:

displaying a color coded map having a plurality of points on the user'"'"'s display screen wherein the color of each said point indicates the magnitude of said overlap and the magnitude of said foreshortening at a corresponding viewing angle;

receiving input from the user to select a desired to select a point of said plurality of points; and

determining said optimal viewing angle as the viewing angle corresponding to the selected point.