Fig 1.

(A) Timing diagram of the UTE-CEST sequence. τ_p is the duration of the saturation pulses, while τ_mix is the mixing time for saturation transfer between successive saturation pules. (B-E) Flowchart of the drift correction for the ΔST map: (B) typical ST signal intensities as a function of time for four interleaved labeling (offset ±3.6 ppm) and control (offset 8 ppm) images. The first data points before reaching steady state for labeling and control images are indicated by red crosses (x); (C) ST signal after drift correction. (D & E) ΔST maps with and without drift correction.