The study of knee tibiofemoral condyle cartilage relaxation characters based on quantitative MR T2 imaging

Osteoarthritis (OA) is a degenerative joint disease that leads to the articular cartilage (AC) degeneration and joint function loss. Early stage OA is primarily associated with proteoglycan (PG) loss and collagen structure changes. The MR T2 imaging is a promising non-invasive diagnostic tool that has shown the potential to reflect changes in the biochemical composition of cartilage with early OA. T2 relaxation times give a quantitative measure of the molecular interactions occurring within the imaged cartilage tissues. It can represent cartilage tissue biochemical character that can be quantified with the help of specific imaging strategies. The goal of this study was to apply Levenberg-Marquardt curve fitting algorithm for T2 mapping quantification and T2 relaxation time calculation to study T2 relaxation characters based on quantitative MR T2 imaging of the tibiofemoral condyle cartilage. The MR T2 images of a healthy male volunteer´s right knee were generated by a 3T MRI scanner using a spin echo multislice multiecho (MSME) Carr-Purcell Meiboom-Gill (CPMG) sequence. The medial and lateral tibiofemoral condyle cartilage was further subdivided into the regions of interest (ROIs) for identifying variation in T2 values. T2 relaxation times mean and standard deviation of ROIs were calculated using Levenberg-Marquardt curve fitting algorithm with correction and without correction. The results show that the Levenberg-Marquardt curve fitting algorithm was feasible for T2 relaxation time calculation of tibiofemoral cartilage, the CPMG sequence was sensitive to cartilage tissue imaging, and T2 parameter can be used for the characterization of articular cartilage tissue.