UCSF

Knee osteoarthritis (OA) is a multifaceted diseases affecting many older adults. A main physiological characteristic of OA is the progressive loss of articular hyaline cartilage. Recently, there have been many proposed techniques that attempt to quantify early hyaline cartilage breakdown associated with OA. Preliminary stages of OA are marked by a reduction in PG and GAG followed by the degradation of the collagen network. Many techniques utilizing magnetic resonance imaging (MRI) have been proposed to noninvasively probe biochemical changes in human osteoarthritic cartilage. T1ρ and T2 relaxation time mapping may be useful as a noninvasive quantification of cartilage degradation. Moreover, osteoarthritic cartilage has displayed elevated voxel spatial heterogeneity of cartilage T1ρ and T2 relaxation time, as calculated by the grey-level co-occurrence (GLCM).

In this study we monitored cross-sectional and longitudinal evaluation of T1ρ and T2 relaxation times, GLCM spatial heterogeneity (texture analysis) of T1ρ and T2 relaxation, and cartilage volume and thickness in OA subjects versus healthy controls. Our results display significant increases over time in GLCM entropy in the medial tibia for both T1ρ and T2 relaxation and in the medial femoral condyle for T1ρ relaxation. A significant decrease in volume and thickness was observed in the medial tibia was also noted. These results indicate medial knee OA cartilage experiences a heightened level of spatial heterogeneity, possibly suggesting a predicative utility of T1ρ and T2 relaxation time texture analysis in the development of medial knee OA.