System and method for image segmentation in generating computer models of a joint to undergo arthroplasty

• US 8,311,306 B2
• Filed: 04/14/2009
• Issued: 11/13/2012
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Otismed Corporation (Stryker Corporation)
• Inventors: Pavlovskaia, Elena, Sarva, Venkata S.
• Primary Examiner(s): FULLER, RODNEY EVAN
• Application Number:
  US12/386,105
• Publication Number:
  US 20090274350A1
• Time in Patent Office: 1,309 Days
• Field of Search: 382/131
• US Class Current: 382/131
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 2034/102 Modelling of surgical devices, implants or prosthesis
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06V 10/24 Aligning, centring, orientation detection or correction of the image
• CPC Class Codes: G06V 10/46 Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56
• CPC Class Codes: G06V 10/471 using approximation functions
• CPC Class Codes: G06V 2201/033 of skeletal patterns

Abstract

Systems and methods for image segmentation in generating computer models of a joint to undergo arthroplasty are disclosed. Some embodiments may include a method of partitioning an image of a bone into a plurality of regions, where the method may include obtaining a plurality of volumetric image slices of the bone, generating a plurality of spline curves associated with the bone, verifying that at least one of the plurality of spline curves follow a surface of the bone, and creating a 3D mesh representation based upon the at least one of the plurality of spline curve.

Claims

1. A method of partitioning an image of a bone into a plurality of regions, the method comprising the acts of:

using a medical imaging machine to obtain a plurality of volumetric image slices of the bone;

employing selective resolution over different areas of the bone in the image slices;

using at least one computer to generate a plurality of spline curves associated with the bone;

verifying that at least one of the plurality of spline curves follow a surface of the bone; and

using at least one computer to create a three dimensional (3D) mesh representation based upon the at least one of the plurality of spline curves.

2. The method of claim 1, wherein a uniform spacing between the plurality of slices is 2 millimeters.

3. The method of claim 1, wherein the plurality with slices are in the sagittal, transversal or coronal directions.

4. The method of claim 1, wherein the volumetric image slices represent a portion of the bone that makes contact with a second bone.

5. The method of claim 1, wherein the plurality of spline curves defines the bone'"'"'s shape and orientation.

6. The method of claim 1, wherein the method yields a planning model of the bone.

7. The method of claim 1, wherein the act of verifying comprises the act of examining neighboring slices in the plurality.

8. The method of claim 1, further comprising the act of integrating a representation of a model bone into the image of the bone.

9. The method of claim 8, where the representation of the model bone has no damaged cancellous or cortical matter.

10. A method of partitioning an image of a bone into a plurality of regions, the method comprising the acts of:

using a medical imaging machine to obtain a plurality of volumetric image slices of the bone;

using at least one computer to generate a plurality of spline curves associated with the bone;

verifying that at least one of the plurality of spline curves follow a surface of the bone; and

using at least one computer to generate a three dimensional (3D) mesh representation based upon the at least one of the plurality of spline curves, wherein at least one image slice within the plurality includes voxels that are distorted through voxel volume averaging.

34. A non-transitory computer readable medium comprising computer executable instructions to perform the method as in any of claims 10, 11, 20, 21, 22, 23 and 29.

11. A method of generating a representation of a model bone, the method comprising the acts of:

obtaining an image scan of the representation as a plurality of slices;

segmenting each slice in the plurality using one or more segmentation curves, wherein the act of segmenting excludes segmenting cartilage associated with the representation of the model bone;

using at least one computer to generate a mesh of the representation;

adjusting each slice in the plurality to include areas where the boundary area of the bone is stable between successive image scans; and

using at least one computer to generate an anchor segmentation such that the anchor segmentation follows a boundary of the representation of the model bone.

12. The method of claim 11, wherein the act of obtaining the image scan occurs through the use of magnetic resonance imaging (MRI).

13. The method of claim 11, wherein Gaussian smoothing is employed.

14. The method of claim 11, wherein the boundary of the representation of the model bone comprises a boundary between cortical and cancellous bone matter.

15. The method of claim 11, further comprising the act of connecting a plurality of cortical and cancellous boundary area together to obtain the anchor segmentation.

16. The method of claim 15, wherein the plurality of cortical and cancellous boundaries are disjoint.

17. The method of claim 11, wherein at least one cancellous voxel is within the anchor segmentation and at least one cortical voxel is external to the anchor segmentation.

18. The method of claim 11, wherein at least one cortical voxels lies along the boundary of the representation of the model bone and at least one cancellous voxel lies adjacent the boundary of the representation of the model bone.

19. The method of claim 11, further comprising the act of generating a 3D mesh representing the representation of the model bone.

20. A method of generating a representation of a model bone, the method comprising the acts of:

obtaining an image scan of the representation as a plurality of slices;

segmenting each slice in the plurality using one or more segmentation curves;

using at least one computer to generate a mesh of the representation;

adjusting each slice in the plurality to include areas where the boundary area of the bone is stable between successive image scans; and

using at least one computer to generate an anchor segmentation such that the anchor segmentation follows a boundary of the representation of the model bone, wherein at least a portion of the representation of the model bone exists between two segmentation curves.

21. A method of generating a representation of a model bone, the method comprising the acts of:

obtaining an image scan of the representation as a plurality of slices;

segmenting each slice in the plurality using one or more segmentation curves;

using at least one computer to generate a mesh of the representation;

adjusting each slice in the plurality to include areas where the boundary area of the bone is stable between successive image scans; and

using at least one computer to generate an anchor segmentation such that the anchor segmentation follows a boundary of the representation of the model bone, wherein osteophytes are excluded from the anchor segmentation.

22. A method of generating a representation of a model bone, the method comprising the acts of:

obtaining an image scan of the representation as a plurality of slices;

segmenting each slice in the plurality using one or more segmentation curves;

using at least one computer to generate a mesh of the representation;

adjusting each slice in the plurality to include areas where the boundary area of the bone is stable between successive image scans;

using at least one computer to generate an anchor segmentation such that the anchor segmentation follows a boundary of the representation of the model bone; and

repositioning a point on the one or more segmentation curves by comparing point placement of adjacent segmentation curves.

23. A method of segmenting a target bone using a representation of a model bone, the method comprising the acts of:

registering a segmented form of the representation to an image scan of the target bone;

refining the registration of the segmented form of the representation near a boundary of the target bone;

using at least one computer to generate a mesh from the segmented form of the representation; and

using at least one computer to generate a plurality of spline curves that approximate the intersection of the mesh and one or more slices from the image scan of the target bone, wherein the act of refining comprises averaging one or more voxels of adjacent slices.

24. The method of claim 23, wherein the method is performed on a joint.

25. The method of claim 23, further comprising applying a transform within one or more slices.

26. The method of claim 25, wherein the act of applying the transforms includes moving points within a plane of the slices but not transversal to the slices.

27. The method of claim 23, further comprising the act of verifying that at least one of the pluralities of spline curves follows a surface of the target bone.

28. The method of claim 27, wherein the act of verifying comprises the act of comparing at least two adjacent slices.

29. A method for refining registration of a representation of a model bone to a target bone, the method comprising the acts of:

using at least one computer to transform an anchor segmentation mesh;

using at least one computer to generate a plurality of random points around the transformed anchor segmentation mesh;

determining if each point in the plurality lies inside one or more of the following meshes;

Inpark-OutLight, InLight-Outpark, or Dark-In-Light determining whether one or more of the plurality of points lie within a threshold distance of the surface of the transformed anchor segmentation mesh; and

adding each point in the plurality as a dark point or light point depending upon whether the point lies within the Inpark-OutLight, InLight-Outpark, or Dark-In-Light meshes and to determine of the point lies inside or outside of the transformed anchor segmentation mesh, wherein the act of determining if each point lies within a threshold distance comprises the acts of;

intersecting the anchor segmentation mesh with each image slice;

noting one or more pixels of the image slice that intersect with the anchor segmentation mesh; and

filtering the one or more pixels outside the threshold distance.

30. The method of claim 29, wherein the plurality of points are within image slices.

31. The method of claim 29, wherein the act of filtering occurs using a Dilate filter.

32. The method of claim 29, wherein the threshold distance is 0.75 millimeters.

33. The method of claim 29, wherein the act of transforming comprises the act of generating one or more spline curves.