T1ρ relaxation time of the meniscus and its relationship with T1ρ of adjacent cartilage in knees with acute ACL injuries at 3 T

Objective: The aim of this study was to assess the reproducibility of meniscus T1 rho measurements, and to study T1 rho relaxation time in the lateral meniscus (LM) and its relationship with adjacent cartilage T1 rho in knees with acute anterior cruciate ligament (ACL) injuries at 3 T magnetic resonance imaging. Method. Quantitative assessment of the meniscus and cartilage was performed in 15 healthy controls and 16 ACL-injured patients using a T1 rho mapping technique. All ACL-injured patients were imaged prior to surgery within 1-3 months of injury. The anterior and posterior horns of LM and medial meniscus (MM) were associated with partitioned weight-bearing cartilage sub-compartments (anterior, central, and posterior). Results: T1 rho measurements in the meniscus showed excellent reproducibility (coefficient of variation (CV) < 5%). Significantly elevated T1 rho values were found in the LM in patients compared with controls (P < 0.01). No differences were found in the MM. Significantly higher T1 rho values were found at the posterior horn compared with the anterior horn of patients' meniscus (P = 0.005). At the posterior sub-compartment of lateral tibia (LT), significantly increased cartilage T1 rho values were found in patients compared with controls (P = 0.002). A significant correlation (R-2 = 0.47, P = 0.007) was found between T1 rho values of posterior horn of LM and T1 rho values of posterior sub-compartment of LT cartilage in patients. Conclusion: A strong injury-related relationship was demonstrated between meniscus and cartilage biochemical changes. T1 rho mapping techniques provide tools to quantitatively evaluate meniscus and cartilage matrix in patients with ACL injuries. Published by Elsevier Ltd on behalf of Osteoarthritis Research Society International.