T1ρ and T2 relaxation times predict progression of knee osteoarthritis

Objective: To evaluate whether T-2 and T-1 rho relaxation times of knee cartilage determined with 3T magnetic resonance imaging (MRI) at baseline predict longitudinal progression of cartilage degenerative changes. Methods: Quantitative analysis of cartilage was performed using 31 MRI with both T-2 and T-1 rho mapping techniques in 55 subjects without evidence of severe osteoarthritis (OA) [Kellgren-Lawrence (KL) score of 0-3] at baseline. Morphological abnormalities of cartilage, menisci, ligaments and bone marrow were analyzed on sagittal fat-saturated intermediate-weighted fast spin echo (FSE) sequences. Progression of degenerative changes was analyzed over a period of 2 years. Progression was detected in 27 subjects while in 28 subjects no changes were found. Differences between T-2 and T-1 rho relaxation times in these two cohorts were compared using one-way analysis of variance (ANOVA) and t tests. Results: Baseline T-2 and T-1 rho values were significantly higher in the progression cohort in all compartments (P < 0.05) except the lateral tibia (LT) for T-2 and the medial tibia (MT) for T-1 rho. Progression of cartilage degenerative disease was most pronounced at the medial femoral condyles and at the femoro-patellar joint; differences between the two cohorts for T-2 and T-1 rho were also most significant in these compartments. Conclusions: T-2 and T-1 rho measurements were significantly higher at baseline in individuals that showed progression of cartilage abnormalities over a period of 2 years and may therefore serve as potential predictors for progression of degenerative cartilage abnormalities in knee OA. (C) 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.