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Cartilage Composition in OAI Cohort

T2 Relaxation Time in the OAI Normal, Incidence and Progression Cohorts

Background

  • T2 relaxation time mapping has been established as one of these techniques and has been shown to be sensitive to water concentration, collagen architecture, and biomechanical characteristics of the hyaline cartilage.
  • This technique has shown promising results in differentiating individuals with and without OA and in characterizing the hyaline cartilage and the menisci in different stages of degeneration.
  • However, these studies were mostly performed at single centers with relatively small patient numbers and only limited information is available on the longitudinal evolution of T2 relaxation times.
  • Given these limitations, yet promising results, T2 relaxation time measurements were included in the Osteoarthritis Initiative (OAI). The OAI is an ongoing 8-year, multi-center, longitudinal cohort study, focusing on knee OA, which currently offers the best available resource to study the role and importance of T2 relaxation time in osteoarthritis.


Aims

  • The overall goal of this project is to study the longitudinal evolution of T2 relaxation time measurements in the OAI in relation to clinical and morphological findings at the knee.
  • To study the prevalence and grade of cartilage and meniscal lesions using the semi-quantitative Whole Organ Magnetic Resonance Imaging Score (WORMS) in normal individuals (n=100), as well as in individuals from the incidence (n=300)* and progression (n=300) cohorts of the OAI, who are 45-70 years old, and to analyze the relationship of these scores with T2 parameters (mean, spatial distribution, and laminar organization) and assess interrelationships between these three groups
  • To determine whether baseline T2 parameters will predict after 2 and 4 years change in WORMS scores and increase in Western Ontario and McMasters (WOMAC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) indices
  • To assess the longitudinal change in T2 parameters, cartilage, and meniscal lesion progression in relation to changes of pain and function scales (WOMAC, KOOS), physical activity (PASE) and physical performance over a period of 2 and 4 years. (Incidence cohort data will be available for 45- to 60-year old individuals from funded U01, AR059507-01).

Semi-quantitative WORMS Grading for the Knee.


Significance and Translational Aspect

  • The overall impact of this project will be to thoroughly investigate and propose imaging biomarkers that will identify individuals at high risk for OA and progression of OA.
  •  The unique study design of the OAI will provide, for the first time, T2 measurements of the cartilage matrix in a large study population that was obtained longitudinally with rigorous quality assurance using the same type of MR scanners.
  • The results of this project obtained in the normal, incidence, and progression cohorts of the OAI will investigate in a large study population, whether T2 measurements may be used as a biomarker to predict development of OA, with concurrent assessments of physical activity, development of pain, as well as radiographic signs of OA and abnormalities on morphological MR sequences.
  • Ultimately these findings will assist in better characterization of patients by clinically using T2 measurements, and these findings will also impact follow-up studies for Project 2.