Individually tailored spatial–spectral pulsed CEST MRI for ratiometric mapping of myocardial energetic species at 3T

PURPOSE: variation across the myocardium leads to spatially variable Cr CEST contrast in healthy myocardium. METHODS: gradient dimension. Complete Z-spectra in the hearts of (n = 10) healthy individuals were acquired using conventional Gaussian saturation and SPSP schemes and supported by phantom studies. RESULTS: values within the myocardium (n = 10) from 0.12 ± 0.02 μT to 0.05 ± 0.01 μT (p < 0.01) and reduced the average SD of Cr CEST contrast in vivo from 10.0 ± 4.3% to 6.1 ± 3.5% (p < 0.05). Results from the hearts of human subjects showed a significant reduction of CEST contrast distribution at 2 ppm, as well as amplitude, when using SPSP saturation. Corresponding phantom experiments revealed PCr-specific contrast generation at body temperature when SPSP saturation was used but combined PCr and Cr contrast generation when Gaussian saturation was used. CONCLUSION: The use of SPSP saturation pulsed CEST resulted in PCr-specific contrast generation and enabled ratiometric mapping of PCr to total Cr CEST contrast in the human heart at 3T.