• cartilage
• MRI
• osteoarthritis

Purpose: To prospectively evaluate morphologic and quantitative relaxometry changes of knee articular cartilage using UHF MRI in patients with symptomatic osteoarthritis of the knee within the first 6 months after receiving intra-articular injections of a hyaluronan derivative.
Materials and methods: This an open-label prospective pilot study in 20 patients suffering from symptomatic and radiographically proven knee OA (Kellgren and Lawrence grade II or III) who underwent UHF MRI examinations before and 45 days and 180 days after receiving intra-articular injections of a hyaluronan derivative. UHF MRI protocol included a 3D bSSFP with constructive interference for morphological evaluation and a ME-SE for T2 relaxometry. Each knee was evaluated by means of the Whole Organ Magnetic Resonance Imaging Score (WORMS) at each timepoint. T2 relaxation times and cartilage volumes were computed for each articular cartilage component (medial femoral, medial tibial, lateral femoral, lateral tibial and femoro-patellar) and longitudinally compared using a repeated mesures ANOVA.
Results: 20 patients with symptomatic knee OA were enrolled (5 K&L grade II, 15 K&L grade 15). After treatment, 84% (16 out 20) patients were clinically defined as responders. No significant changes in cartilage volume and average WORMS score were found. A significant (p=0.027) decrease in T2 relaxation times was found in the lateral tibial compartment.
Conclusions: articular cartilage T2 relaxation times have the potential to be a useful biomarker in the evaluation of treatment response after intra-articular injections of a hyaluronan derivative in knee OA.