Assessing the condition of a joint and assessing cartilage loss

• US 9,286,686 B2
• Filed: 02/26/2007
• Issued: 03/15/2016
• Est. Priority Date: 09/14/1998
• Status: Expired due to Term

• 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
• Primary Examiner(s): Le, Long V
• Assistant Examiner(s): HOFFA, ANGELA MARIE
• Application Number:
  US11/678,763
• Publication Number:
  US 20070203430A1
• Time in Patent Office: 3,305 Days
• Field of Search: 600/410
• US Class Current: 1/1
• 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 electronically reconstructing cartilage in a patient'"'"'s diseased or damaged joint, which method comprises:

(a) obtaining a volumetric representation of cartilage of said patient'"'"'s diseased or damaged joint in which said volumetric representation demonstrates normal and defective cartilage of said patient'"'"'s diseased or damaged joint;

(b) identifying a volume of interest including a cartilage defect associated with the patient'"'"'s diseased or damaged joint, the cartilage defect being surrounded by normal cartilage;

(c) estimating depth of lost cartilage tissue of the cartilage defect relative to expected cartilage tissue without the cartilage defect, based on the normal cartilage surrounding the cartilage defect; and

(d) electronically reconstructing an estimated normal cartilage surface in the volume of interest, wherein the cartilage defect is eliminated based on the estimated depth of the lost cartilage tissue.

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

3. The method of claim 1 further comprising, devising, based on the estimated depth of the lost cartilage tissue, a treatment for defective cartilage with a therapy selected from the group consisting of one or more chondroprotective or chondroregenerative agents, osteochondral allografting, cartilage transplantation, osteotomy or joint replacement surgery, and any combination thereof.

4. The method of claim 1, wherein said method is carried out on the same volume of interest at an initial time T₁ and at a later time T₂ and said method includes an analysis of degree of degeneration of the cartilage of said patient'"'"'s diseased or damaged joint between T₁ and T₂.

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

6. The method of claim 5, wherein the MRI technique includes first obtaining a series of two-dimensional views of the patient'"'"'s diseased or damaged joint, and mathematically integrating the series to give a three-dimensional image.

7. The method of claim 5, wherein the MRI technique employs a gradient echo, spin echo, fast-spin echo, driven equilibrium fourier transform, or spoiled gradient echo technique.

8. A method of electronically reconstructing cartilage in a patient'"'"'s diseased or damaged joint, which method comprises:

(a) obtaining a volumetric representation of cartilage of said patient'"'"'s diseased or damaged joint demonstrating normal and defective cartilage of said patient'"'"'s diseased or damaged joint;

(b) estimating, based on the normal cartilage in the volumetric representation, depth of lost cartilage tissue relative to expected cartilage tissue without cartilage defect; and

(c) electronically reconstructing an estimated normal cartilage surface of the joint wherein the cartilage defect is eliminated based on the estimated depth of the lost cartilage tissue.

9. The method of claim 8, further comprising estimating thickness, area or volume of lost cartilage tissue by determining a thickness difference between said defective cartilage and said normal cartilage in said volumetric representation.

10. The method of claim 9, wherein said difference is determined by measuring differences in thicknesses of said normal and said defective cartilage, in biochemical content of said normal and said defective cartilage, or in relaxation time of said normal and said defective cartilage.

11. The method of claim 8, wherein said method is carried out at an initial time T₁ and at a later time T₂ and said estimating includes an estimation of volume of cartilage lost between T₁ and T₂.