To determine the relationship between changes in the extracellular matrix (ECM) and T1ρ and T2 values in vivo. The ECM is composed of proteoglycan (PG), collagen, and water. It has been unclear which of the ECM constituents affects T1ρ and T2 mapping in living human cartilage.
Materials and Methods:
Sagittal T1ρ and T2 maps were preoperatively obtained from 20 knee osteoarthritis patients. Osteochondral samples harvested from the resected tibial plateaus during total knee arthroplasty were consistent with the MRIs of the patients' knees. Parameters that included histological grading of cartilage degeneration, glycosaminoglycan (GAG) content (which constitutes PG), presence of collagen anisotropy and water content were evaluated along with T1ρ and T2 values, and statistical analysis was performed using multiple regression analysis.
T1ρ and T2 values were significantly correlated with the degree of cartilage degeneration (β = 0.397 and 0.357, respectively) and the GAG content (β = −0.340 and −0.244, respectively).
The present study demonstrated that T1ρ and T2 values reflect the GAG content of the cartilage and can indicate cartilage degeneration in vivo. Use of these parameters can facilitate the noninvasive diagnosis and evaluation of cartilage degeneration. J. Magn. Reson. Imaging 2012;35:147-155. © 2011 Wiley Periodicals, Inc.