GlycoCEST using FISPCEST

Introduction: In vivo and non-invasive measures of hepatic and muscular glycogen are needed to effectively study diabetes and metabolism in humans and animals. C13-MRS methods have been shown to accurately measure glycogen levels; however, C13-MRS suffers from relatively poor spatial resolution and is not available on the majority of clinical MRI scanners. More recently, glycogen’s inherent CEST effect has been proposed as an alternative to C13-MRS. While this initial “GlycoCEST” work is promising, the in vivo utility of the GlycoCEST technique is limited because of the long acquisition times (1-3 hours) for quantitative CEST-MRI acquisitions. In this study, we have developed and optimized a rapid GlycoCEST acquisition using our recently developed FISP-CEST technique to obtain quantitative glycogen CEST spectra in phantoms and ex vivo livers in 15-45 minutes.