Edward T. Randtke1, Liu Qi Chen1, Rene Corrales1, Marty Pagel2
1Chemistry and Biochemistry, University of Arizona, Tucson, AZ, United States; 2Biomedical Engineering, University of Arizona, Tucson, AZ, United States
Most CEST MRI methods fail to accurately determine fast exchange rates (> 20% of the chemical shift difference). We have investigated the accuracies of the Bloch fitting, QUEST, QUESP, omega-plot, and concentration-dependent methods using theoretical simulations and experimental measurements. We have also developed new analysis methods and compared these methods with existing analysis methods. Our results show that the Bloch fitting method is most accurate for determining slow and fast exchange rates, the omega-plot method is acceptable for determining slow exchange rates, and the Hanes-Woolf linear QUESP method is acceptable for determining fast exchange rates.