Assessing the condition of a joint and assessing cartilage loss

• US 7,184,814 B2
• Filed: 09/14/2001
• Issued: 02/27/2007
• Est. Priority Date: 09/14/1998
• Status: Expired due to Term

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford University)
• Inventors: Lang, Philipp, Steines, Daniel
• Primary Examiner(s): Casler; Brian L.
• Assistant Examiner(s): Jung; William C.
• Application Number:
  US09/953,373
• Publication Number:
  US 20020177770A1
• Time in Patent Office: 1,992 Days
• Field of Search: 600/407, 600/410, 600/416, 600/425, 128/920, 128/922, 382/131, 703/11, 703/2, 703/12, 324/307, 324/309
• US Class Current: 600/416
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/107 Measuring physical dimensions, e.g. size of the entire body or parts thereof
• 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 5/4514 Cartilage
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 6/03 Computed tomography [CT] echo-tomography A61B8/14
• CPC Class Codes: A61B 8/0875 for diagnosis of bone A61B5/4504 takes precedence
• CPC Class Codes: G01R 33/50 based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
• CPC Class Codes: G01R 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T
• CPC Class Codes: G06T 2207/10088 Magnetic resonance imaging [MRI]
• CPC Class Codes: G06T 2207/30008 Bone
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/187 involving region growing; involving region merging; involving connected component labelling

Abstract

Methods are disclosed for assessing the condition of a cartilage in a joint and assessing cartilage loss, particularly in a human knee. The methods include converting an image such as an MRI to a three dimensional map of the cartilage. The cartilage map can be correlated to a movement pattern of the joint to assess the affect of movement on cartilage wear. Changes in the thickness of cartilage over time can be determined so that therapies can be provided. The amount of cartilage tissue that has been lost, for example as a result of arthritis, can be estimated.

Claims

1. A method of assessing cartilage damage or disease in a point of a living subject, said joint comprising cartilage and bone on either side of the joint, which method comprises:

(a) obtaining a three-dimensional volumetric representation of cartilage of said joint in which said three-dimensional volumetric representation demonstrates volume or thickness or biochemical contents or relaxation time of both normal and damaged or diseased cartilage of said joint; and

(b) electronically determining at least one margin between damaged or diseased cartilage and normal cartilage in three dimensions.

2. The method of claim 1, wherein said margin is determined by detecting a difference in said thickness, said biochemical contents or said relaxation time between said normal and said damaged or diseased cartilage.

3. The method of claim 1, wherein said margin of said damaged or diseased cartilage is used to determine an area, volume, or thickness of damaged or diseased cartilage in said joint or a percentage of total cartilage surface or of articular surface area or of weight-bearing surface area represented by said damaged or diseased cartilage in said joint.

4. The method of claim 1, wherein the joint is a knee joint.

5. The method of claim 1, wherein said three dimensional volumetric representation is used to devise a treatment for damaged or diseased cartilage or bone.

6. The method of claim 1, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said method includes an analysis of degree of degeneration of the cartilage between T₁ and T₂.

7. The method of claim 1, wherein the three-dimensional volumetric representation of cartilage is obtained by a magnetic resonance imaging (MRI) technique.

8. The method of claim 7, wherein the MRI technique first obtains a series of two-dimensional views of the joint which are then integrated to give three-dimensional images.

9. The method of claim 7, wherein the MRI technique employs a gradient echo, spin echo, fast-spin echo, driven equilibrium Fourier transform, or spoiled gradient echo technique.

10. The method of claim 1, wherein said three-dimensional volume representation demonstrates thickness of both normal and damaged or diseased cartilage.

11. The method of claim 1, wherein said three-dimensional volumetric representation demonstrates biochemical contents of both normal and damaged or diseased cartilage.

12. The method of claim 1, wherein said three-dimensional volumetric representation demonstrates relaxation time of both normal and damaged or diseased cartilage.

13. The method of claim 1, wherein said margin of damaged or diseased cartilage is used to determine an area, volume, or thickness of damaged or diseased cartilage in said joint.

14. The meted of claim 1, wherein said margin of damaged or diseased cartilage is used to determine a percentage of total cartilage surface represented by said damaged or diseased cartilage in said joint.

15. The meted of claim 1, wherein said margin of damaged or diseased cartilage is used to determine a percentage of articular surface represented by said damaged or diseased cartilage in said joint.

16. The method of claim 1, wherein said margin of damaged or diseased cartilage is used to determine a percentage of weight bearing surface area represented by said damaged or diseased cartilage in said joint.

17. A method of assessing cartilage damage or disease in a joint of a living subject, said joint comprising cartilage and accompanying bone on either side of the joint, which method comprises:

(a) obtaining a three-dimensional volumetric representation of cartilage of said joint demonstrating volume or thickness or biochemical contents or relaxation time of both normal and diseased or damaged cartilage of said joint; and

(b) electronically estimating thickness or area or volume of lost cartilage tissue relative to expected cartilage tissue in absence of disease or damage.

18. The method of claim 17, wherein said thickness, area or volume of said cartilage tissue that has been lost is performed by determining a margin between said diseased or damaged cartilage and said normal cartilage in said three-dimensional volumetric representation.

19. The method of claim 18, wherein said margin is determined by measuring changes in said thickness of said normal and said diseased cartilage, in said biochemical content of said normal and said diseased cartilage, or in said relaxation time of said normal and said diseased cartilage.

20. The method of claim 17, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said determination includes a determination of the amount of cartilage lost between T₁ and T₂.

21. The method of claim 20, wherein said amount of cartilage tissue lost is determined as thickness or area or volume or content in one or more biochemical components of said cartilage tissue lost.

22. The method of claim 21, wherein said thickness, area, volume or content of said cartilage tissue lost is determined by determining a margin between diseased or damaged cartilage and normal cartilage.

23. The method of claim 20, wherein said change in said diseased cartilage or said cartilage tissue lost is determined without matching data obtained at T₁ and T₂.

24. The method of claim 17, wherein said three-dimensional volumetric representation demonstrates thickness of both normal and damaged or diseased cartilage.

25. The method of claim 17, wherein said three-dimensional volumetric representation demonstrates biochemical contents of both normal and damaged or diseased cartilage.

26. The method of claim 17, wherein said three-dimensional volumetric representation demonstrates relaxation time of both normal and damaged or diseased cartilage.

27. A method of assessing cartilage damage or disease in a joint of a living subject, said joint comprising cartilage and bone on either side of the joint, which method comprises:

(a) obtaining a three-dimensional volumetric representation of cartilage of said joint in which said volumetric representation demonstrates volume or thickness or biochemical contents or relaxation time of both normal and damaged or diseased cartilage of said joint; and

(b) electronically placing a volume of interest smaller than the articular cartilage surface in or around an area of diseased or damaged cartilage.

28. The method of claim 27, wherein said region of interest is determined by detecting a difference in said volume, said thickness, said biochemical contents or said relaxation time between said normal and said damaged or diseased cartilage.

29. The method of claim 27, wherein said region of interest is used to determine an area, volume, or thickness of damaged or diseased cartilage in said joint or a percentage of total cartilage surface or of articular surface area or of weight-bearing surface area represented by said damaged or diseased cartilage in said joint.

30. The method of claim 27, wherein the joint is a knee joint.

31. The method of claim 27, wherein said volumetric representation is used to devise a treatment for damaged or diseased cartilage or bone.

32. The method of claim 27, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said method includes an analysis of degree of degeneration of the cartilage between T₁ and T₂.

33. The method of claim 27, wherein the three-dimensional volumetric representation of cartilage is obtained by a magnetic resonance imaging (MRI) technique.

34. The method of claim 33, wherein the MRI technique first obtains a series of two-dimensional views of the joint which are then integrated to give three-dimensional images.

35. The method of claim 33, wherein the MRI technique employs a gradient echo, spin echo, fast-spin echo, driven equilibrium Fourier transform, or spoiled gradient echo technique.

36. A method of assessing cartilage damage or disease in a joint of a living subject said joint comprising cartilage and bone on either side of the joint which method comprises:

(a) obtaining a three-dimensional dataset of the articular cartilage that includes information on volume or thickness or biochemical contents or relaxation time of said cartilage;

(b) electronically selecting a subregion of the articular cartilage that is smaller than the cartilage surface; and

(c) performing a quantitative measurement of volume or thickness or biochemical contents or relaxation time of said cartilage in said subregion.

37. The method of claim 36, wherein said region of interest is determined by detecting a difference in said volume, said thickness, said biochemical contents or said relaxation time between said normal and said damaged or diseased cartilage.

38. The method of claim 36, wherein said region of interest is used to determine an area, volume, or thickness of damaged or diseased cartilage in said joint or a percentage of total cartilage surface or of articular surface area or of weight-bearing surface area represented by said damaged or diseased cartilage in said joint.

39. The method of claim 36, wherein the joint is a knee joint.

40. The method of claim 36, wherein said three-dimensional dataset is used to devise a treatment for damaged or diseased cartilage or bone.

41. The method of claim 36, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said method includes an analysis of degree of degeneration of the cartilage between T₁ and T₂.

42. The method of claim 36, wherein the three-dimensional dataset of cartilage is obtained by a magnetic resonance imaging (MRI) technique.

43. The method of claim 42, wherein the MRI technique first obtains a series of two-dimensional views of the joint which are then integrated to give three-dimensional images.

44. The method of claim 42, wherein the MRI technique employs a gradient echo, spin echo, fast-spin echo, driven equilibrium Fourier transform, or spoiled gradient echo technique.