Advanced Spatial-Spectral Pulse Design for Metabolite Specific Filtered CEST in the Human Heart

Chemical Exchange Saturation Transfer (CEST) MRI has been used to probe metabolism via total creatine contrast using conventional contrast generation with Gaussian saturation. We developed a spatial-spectral (SPSP) saturation pulsed CEST protocol to separate the contrast generated by metabolic subcomponents creatine and phosphocreatine (PCr) in phantoms and the human heart (n=10). Phantom studies revealed uniform CEST contrast for creatine and PCr following saturation with Gaussian pulses, and selective PCr contrast following saturation with SPSP pulses. Human studies revealed both enhanced B1-uniformity and selective PCr contrast with SPSP saturation, enabling quantitation of the PCr/total creatine ratio in the myocardium.