Repeatability and Reproducibility of Quantitative Sodium MRI of Cartilage in vivo at 3T and 7T

Guillaume Madelin¹, James Babb¹, Ding Xia¹, Gregory Chang¹, Alexej Jerschow², Ravinder R. Regatte¹

Quantitative sodium MRI is highly specific to glycosaminoglycan content and could be used to assess the biochemical degradation of cartilage in early stages of osteoarthritis. The aim of this study is to assess the reproducibility and repeatability for sodium quantification in cartilage in vivo using intra-day and inter-day acquisitions at 3T and 7T, with a 3D radial sequence, with and without fluid suppression. The measured RMS CV are in the range 7-14%, therefore the repeatability and reproducibility CV of sodium quantification using sodium MRI compare favorably with the CV of other proton-based MRI techniques (T2 map, T1rho map, dGEMRIC).