Judong Pan MD, Presenter: Nothing to Disclose

Jean-Baptiste Pialat MD, Abstract Co-Author: Nothing to Disclose

Tom Joseph, Abstract Co-Author: Nothing to Disclose

Thomas M. Link MD, Abstract Co-Author: Consultant, General Electric Company

To study the prevalence of osteoarthritis (OA) related knee morphological abnormalities in the normal control cohort using 3T MRI and investigate the characteristics and evolution of cartilage T2 values in relation to morphological abnormalities with a longitudinal study.

100 subjects aged 45 to 78 who are free of OA symptoms and risk factors were selected from the Osteoarthritis Initiative (OAI) control cohort. Both baseline and 2-year follow-up data were analyzed. Knee abnormalities were analyzed using the whole-organ MR imaging score (WORMS) by three musculoskeletal radiologists. Knee cartilage T2 maps were obtained using a standardized segmentation technique. Statistical significance was determined using Student’s t-test, ANOVA, multivariate correlation tests, Χ2 tests, and multiple regression models.

We identified a high prevalence of focal knee abnormalities in these non-symptomatic subjects (90% at baseline and 91% at 2-year follow-up). The prevalence of cartilage lesions was particularly high (85% at baseline and 83% at follow-up) and cartilage T2 values (all compartments combined) were significantly higher at follow-up compared to baseline (p = 0.0002). All cartilage compartments showed significant T2 elevation except for patella and trochlea. Comparison between subjects with lower baseline T2 and those with higher T2 did not show significant difference in WORMS scores or prevalence of morphological abnormalities. However, subjects with greater longitudinal T2 elevation (ΔT2, all compartments combined) had significantly higher cartilage T2 values at follow-up (p = 0.0354). Regression analysis of longitudinal changes in cartilage WORMS scores (ΔWORMS, all compartments combined) using ΔT2 as a predictor showed a significant linear relationship (ΔWORMS = 0.1117401 + 0.0557426 x ΔT2, p = 0.043).

Our data suggested a very prevalence of preclinical OA in healthy subjects as manifested by focal knee abnormalities detected by 3T MRI. A significant longitudinal T2 elevation over two years was detected. Greater T2 elevation was associated with increased progression of OA-related knee morphological abnormalities.

MR-based cartilage T2 quantification may be used as a biomarker for preclinical OA. Specifically, longitudinal T2 changes may be helpful in identifying people who are at risk for developing early OA.

Pan, J, Pialat, J, Joseph, T, Link, T, Knee Cartilage T2 Characteristics and Evolution in Relation to Morphological Abnormalities Detected by 3T MRI: A Longitudinal Study of the Normal Control Cohort from the Osteoarthritis Initiative.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9003170.html