Figure 9. Comparing different CEST-MRF acquisition schedules.

A phantom containing three vials of 50 mM L-arginine at pH 4, 4.5, and 5 was imaged using a 9.4T scanner. The dot-product matched L-arg concentration (d-f) and amine proton exchange rate (g-i) are shown for three different acquisition schedules, including the random acquisition schedule used in Coehn et al.⁵⁹ (left column); a different random acquisition schedule of similar length (center column), which also varied the saturation pulse duration, the repetition time, and the readout flip angle; and a schedule based on a z-spectrum obtained using a fixed saturation power of 2uT, at 7 to −7 ppm with 0.25 increments (right column).