Longitudinal analysis of MRI T(2) knee cartilage laminar organization in a subset of patients from the osteoarthritis initiative.

The purpose of this pilot study was to longitudinally quantify the T(2) laminar integrity of knee cartilage in a subset of subjects with osteoarthritis from the Osteoarthritis Initiative at baseline, 1-year follow-up, and 2-year follow-up. Cartilage from 13 subjects was divided into six compartments and subdivided into deep and superficial layers. At each time point, mean T(2) values in superficial and deep layers were compared. Longitudinal analysis included full-thickness mean T(2), mean deep T(2), mean superficial T(2), mean T(2) laminar difference, mean percentage T(2) laminar difference, and two-dimensional measures of cartilage thickness. More compartments showed significantly higher superficial T(2) than deep T(2) values at baseline and 1-year follow-up compared to 2-year follow-up. No significant longitudinal changes of full-thickness mean T(2) and superficial T(2) values were observed. Significant longitudinal changes were observed in the deep T(2) values, T(2) laminar difference, and percentage T(2) laminar difference. Cartilage thickness had no influence on T(2) analysis. Results of this study suggest that laminar analysis may improve the sensitivity to detect longitudinal T(2) changes and that disruption of the T(2) laminar organization of knee cartilage may be present in knee osteoarthritis progressors. Further investigation is warranted to evaluate the potential of the presented methodology to better characterize evolution and pathophysiology of osteoarthritis.