System for interactive 3D object extraction from slice-based medical images

• US 6,606,091 B2
• Filed: 02/06/2001
• Issued: 08/12/2003
• Est. Priority Date: 02/07/2000
• Status: Active Grant

• Current Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Original Assignee: Siemens Corporate Research Incorporated (Siemens AG)
• Inventors: Liang, Cheng-Chung, Moeller, Thomas
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US09/777,531
• Publication Number:
  US 20010033283A1
• Time in Patent Office: 917 Days
• Field of Search: 345/419, 345/420, 345/424, 345/606, 345/753, 345/757, 345/848, 345/850, 345/851, 345/852
• US Class Current: 345/424
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation

Abstract

The present invention relates to a method and a system for extracting a 3D region of interest from a stack of medical scan slices which is still a challenging task even in this new millennium. One difficulty is that there is no robust automatic algorithm that can handle all the different situations and applications. Human intervention is usually unavoidable for extracting desired area or organs. However, without convenient tools, it is a tedious job for human being to go through hundred or thousand of slices just to extract region of interest. A system combines and modifies several advanced techniques to help a user extract volume of interest very easily and quickly. The technique of livewire for initial-delineate and modify regions of interest from 2D slices is utilized. Then variational interpolation technique is employed to derive a 3D shape from these delineated 2D contours. The 3D shape can be visualized as is or converted to a 3D solid for volume visualization or masking out of the undesirable parts of a data set.

Claims

1. A method for reconstructing shapes in a three dimensional set of image data, the steps comprising:

(a) using a data set of two dimensional images to provide a displayed image wherein at least one image of the set is non-parallel to at least one other image of the set;

(b) applying indications on the displayed image;

(c) developing a surface reconstruction from said indications of the displayed image;

(d) polygonizing the surface reconstruction of the displayed image;

(e) using the polygonized surface of the displayed image to develop the displayed image into a reconstructed shape; and

(f) displaying the reconstructed shape.

2. The method according to claim 1 wherein prior to step (f), the polygonized surface reconstruction of the displayed image is filled in an interior area using voxelization to obtain a solid three dimensional image of said reconstructed surface and said solid three dimensional image is then displayed as the reconstructed shape.

3. The method according to claim 2 wherein said polygonized surface identifies data representative of an obscuring portion of the displayed image and a subtracted data set representative of the obscuring portion is developed so that the obscured portion can be removed and the rest of the displayed image visualized.

4. The method according to claim 3 wherein said rest of the displayed portion is visualized on a display by laying said polygonal patches into a discrete volumetric grid and filling in an interior area of said reconstructed surface using voxelization thereby obtaining a solid three dimensional image of said reconstructed surface.

5. The method according to claim 1 wherein said data set comprises at least one stack of two dimensional image scan slices haying salient features and at least one slice of the stack is non-parallel to at least one other slice of the stack.

6. The method according to claim 1 wherein said developing step (c) includes reconstructing a surface image using subsampled contour points of said data set and a variational implicit function to obtain a set of parameters that describe a three dimensional shape of said reconstructed surface image.

7. The method according to claim 6 wherein said reconstruction is sped up by reducing the number of contour points selected for subsampling.

8. The method according to claim 7 wherein the steps of claim 1 are repeated to obtain a better approximate three dimensional image by increasing the number of contour points selected for subsampling, the contour points being selectable from slices that are non-parallel to other slices having selected contour points.

9. The method according to claim 1 wherein said surface reconstruction of the displayed image in step (d) is approximated utilizing polygonal patches.

10. The method according to claim 1 wherein said solid three dimensional image is displayed as a solid.

11. The method according to claim 1 wherein said solid three dimensional image obtained is used as a mask to constrain a data set.

12. The method according to claim 1 wherein said solid three dimensional image obtained is used as a mask, the method further comprising:

using the mask to remove the data set overlapped by the mask; and

after removing the portion of the data set occupied by the mask, revealing the area of the data set that is outside of the mask but obscured by the mask.

13. A method for reconstructing shapes in a three dimensional set of image data, the steps comprising:

(a) using a data set of two dimensional images to provide a displayed image;

(b) applying indications on the displayed image and drawing two dimensional contours from two dimensional image scan slices utilizing livewire techniques;

(c) developing a surface reconstruction from said indications of the displayed image;

(d) polygonizing the surface reconstruction of the displayed image;

(e) using the polygonized surface of the displayed image to develop the displayed image into a reconstructed shape; and

(f) displaying the reconstructed shape.

14. The method according to claim 13 wherein said livewire techniques include switching between livewire drawing and freehand drawing by a user with a switching mechanism permitting a user to draw a troublesome portion of a contour by freehand and returning to live wire drawing when desired.

15. The method according to claim 14 wherein the switching mechanism is disposed relative to a mouse device.

16. The method according to claim 13 wherein said livewire technique includes overlaying one scan slice with another scan slice and clicking a point on a contour to move it to a desired location in order for all neighboring pieces to be moved into registration when said slices are aligned well on an area of interest in said slices.

17. The method according to claim 13 wherein said livewire technique includes inputting a contour by using a graphical wireframe cube and cutting planes through said cube so that an accompanied multiplanar projection image of the culling plane through said data set is displayed along side said cube and that by rotating said cube and moving said cutting plane an appropriate viewing plane can be selected that provides a significant contour and shape features of an area of interest.

18. A system for reconstructing shapes in a three dimensional set of image data, comprising:

(a) a data set of two dimensional images to provide a displayed image wherein at least one image of the set is non-parallel to at least one other image of the set;

(b) means for applying indications on the displayed image;

(c) means for developing a surface reconstruction from said indications of the displayed image;

(d) means for polygonizing the surface reconstruction of the displayed image;

(e) means for developing the displayed image into a reconstructed shape using the polygonized surface of the displayed image; and

(f) means for displaying the reconstructed shape.

19. The system according to claim 18, further comprising voxelization means for obtaining a solid three dimensional image of said reconstructed surface prior to displaying the reconstructed shape by filling the polygonized surface reconstruction of the displayed image in an interior area and then displaying said solid three dimensional image as the reconstructed shape.

20. The system according to claim 19 wherein said polygonized surface identifies data representative of an obscuring portion of the displayed image and a subtracted data set representative of the obscuring portion is developed so that the obscured portion can be removed and the rest of the displayed image visualized.

21. The system according to claim 20 wherein said rest of the displayed portion is visualized on a display by laying said polygonal patches into a discrete volumetric grid and filling in an interior area of said reconstructed surface using voxelization to thereby obtain the solid three dimensional image of said reconstructed surface.

22. The system according to claim 19 wherein said solid three dimensional image obtained is displayed as a solid.

23. The system according to claim 19 wherein said solid three dimensional image obtained is used as a mask to constrain a data set.

24. The system according to claim 19 wherein said solid three dimensional image obtained is used as a mask, the method further comprising:

using the mask to remove the data set overlapped by the mask; and

after removing the portion of the data set occupied by the mask, revealing the area of the data set that is outside of the mask but obscured by the mask.

25. The system according to claim 18 wherein said data set comprises at least one stack of two dimensional image scan slices having salient features and at least one slice of the stack is non-parallel to at least one other slice of the stack.

26. The system according to claim 18 wherein said means for developing includes reconstructing a surface image using subsampled contour points of said data set and a variational implicit function to obtain a set of parameters that describe a three dimensional shape of said reconstructed surface image.

27. The system according to claim 18 wherein said reconstruction is sped up by reducing the number of contour points selected for subsampling.

28. The system according to claim 18 further comprising repetition means for obtaining a better approximate three dimensional image by increasing the number of contour points selected for subsampling.

29. The system according to claim 18 wherein said surface reconstruction of the displayed image is approximated utilizing polygonal patches.

30. A system for reconstructing shapes in a three dimensional set of image data, comprising:

(a) a data set of two dimensional images to provide a displayed image;

(b) means for applying indications on the displayed image wherein said means for applying includes drawing the two dimensional contours from two dimensional image scan slices utilizing livewire techniques;

(c) means for developing a surface reconstruction from said indications of the displayed image;

(d) means for polygonizing the surface reconstruction of the displayed image;

(e) means for developing the displayed image into a reconstructed shape using the polygonized surface of the displayed image; and

(f) means for displaying the reconstructed shape.

31. The system according to claim 30 wherein said livewire techniques are provided by a means for switching between a livewire drawing and a freehand drawing by a user with a switching mechanism for permitting a user to draw a troublesome portion of a contour by freehand and returning to the livewire drawing when desired.

32. The system according to claim 31, further comprising a mouse device disposed relative to the switching mechanism.

33. The system according to claim 30 wherein said livewire techniques includes overlaying one scan slice with another scan slice and clicking a point on a contour to move it to a desired location in order for all neighboring pieces to be moved into registration when said slices are aligned well on an area of interest in said slices.

34. The system according to claim 30 wherein said livewire techniques includes providing a graphical wireframe cube and cutting planes through said cube to input a contour so that an accompanied multiplanar projection image of the cutting plane through said data set is displayed along side said cube and that by rotating said cube and moving said cutting plane an appropriate viewing plane can be selected that provides a significant contour and shape features of an area of interest.