Characterizing the spatial distribution of cartilage T2 using texture analysis

Gabrielle Blumenkrantz, Julio Carballido-Gamio, Ben Hyun, John A. Lynch, Thomas M. Link, Sharmila Majumdar

Quantitative T2 relaxation time has been used as a noninvasive marker of cartilage degeneration, as it is sensitive to tissue hydration and biochemical composition. In early cartilage degeneration, changes in the extracellular matrix (e.g., disorganization and breakdown of collagen network) increase the mobility of water, thus increasing T2 relaxation time. Previous studies have demonstrated elevated T2 relaxation time in osteoarthritis (OA) subjects as compared to healthy subjects, have reported spatial variations in T2 values from the radial zone to the articular cartilage surface, and have shown different visual patterns of T2 values in pre-arthritic, early arthritic and healthy hip cartilage. These results demonstrate that the spatial distribution of cartilage T2 values reflect the biochemical changes in OA. Our research aims to quantify the spatial distribution of cartilage T2 values using grey level cooccurrence matrix (GLCM) texture analysis. We aim to characterize the spatial distribution of cartilage T2 in OA patients and age-matched healthy subjects and to analyze the longitudinal changes in the texture of cartilage T2. The figure below shows representative cartilage T2 maps from a patient with severe OA, mild OA and a control. Visually, the spatial distribution of cartilage T2 pixels is more heterogeneous in the OA patients.