CEST MRI of Human Knee Cartilage at 3T and 7T

Anup Singh¹, Mohammad Haris¹, Kejia Cai¹, Victor Babu¹, Feliks Kogan¹, Hari Hariharan¹, Ravinder Reddy¹

The sensitivity of gagCEST in human knee cartilage is evaluated at 3T and 7T field strengths. Calculated gagCEST values without accounting for B0 inhomogeneity (~0.6 ppm) were > 20%. After B0 inhomogeneity correction, calculated gagCEST values were negligible at 3T and ~6% at 7T. Results obtained with varying saturation pulse durations and amplitudes as well as the consistency between numerical simulations and our experimental results indicate that the negligible gagCEST observed at 3T is due to direct saturation effects and fast exchange rate. At high fields such as 7T, this method holds promise as a viable clinical technique.