Assessing the Condition of a Joint and Assessing Cartilage Loss

• US 20070203430A1
• Filed: 02/26/2007
• Published: 08/30/2007
• Est. Priority Date: 09/14/1998
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Lang, Philipp, Steines, Daniel
• Granted Patent: US 9,286,686 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• 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 joint comprising cartilage and accompanying bone on either side of the joint, which method comprises (a) obtaining a three-dimensional map of cartilage of said joint in which said map demonstrates thickness or biochemical contents or relaxation time of both normal and damaged or diseased cartilage of said joint, and (b) determining at least one margin between damaged or diseased cartilage and normal cartilage in said three-dimensional map.

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 area 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 map 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 claim 1, wherein the three-dimensional map 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 mathematically integrated to give a three-dimensional image.

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

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

(a) obtaining a three-dimensional map of cartilage of said joint demonstrating thickness or biochemical contents or relaxation time of both normal and diseased or damaged cartilage of said joint, and (b) estimating thickness or area or volume of lost cartilage tissue relative to expected cartilage tissue in absence of disease or damage.

11. The method of claim 10, 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 map.

12. The method of claim 11, 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.

13. The method of claim 10, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said determination includes a determination of amount of cartilage lost between T₁ and T₂.

14. The method of claim 13, 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.

15. The method of claim 14, 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.

16. The method of claim 13, wherein said change in said diseased cartilage or said cartilage tissue lost is determined without matching data obtained at T₁ and T₂.