Volumetric Multislice GagCEST Imaging of Articular Cartilage: Optimization and Comparison With T1rho

Purpose: To develop and optimize a multislice glycosaminoglycan (GAG) chemical exchange saturation transfer (GagCEST) sequence for volumetric imaging of articular cartilage, and to validate the sequence against T-1 rho relaxation times in whole joint imaging of tibiotalar cartilage. Methods: Ex vivo experiments were used to observe the effect of the number of partitions and shot TR on signal-tonoise ratio and measured GagCEST(asym). GagCEST imaging of the entire tibiotalar joint was also performed on 10 healthy subjects. The measured GagCEST(asym) was compared and correlated with T-1 rho relaxation times. Results: Ex vivo studies showed a higher average GagCEST(asym) from articular cartilage on multislice acquisitions acquired with two or more partitions than observed with a single-slice acquisition. In healthy human subjects, an average GagCEST(asym) of 8.860.7% was observed. A coefficient of variation of GagCEST(asym) across slices of less than 15% was seen for all subjects. Across subjects, a Pearson correlation coefficient of +/- 0.58 was observed between the measured GagCEST(asym) and T-1 rho relaxation times. Conclusions: We demonstrated the feasibility and optimization of multislice GagCEST mapping of articular cartilage. Volumetric analysis and decreased scan times will help to advance the clinical utility of GagCEST imaging of articular cartilage. (C) 2016 International Society for Magnetic Resonance in Medicine