Abstract: In chemical exchange saturation transfer (CEST) imaging, the relaxation recovery of the longitudinal magnetization during the signal acquisition process results in a decrease in CEST contrast. Consequently, the CEST saturation mode and the corresponding k-space filling method significantly influence both the image quality and quantitative results of CEST. In this paper, simulations and human experiments were conducted to examine the impact of various k-space filling strategies within the fast low angle shot (FLASH) sequence on the quality of brain amide proton transfer (APT) images and on the quantitative analysis of the magnetization transfer ratio asymmetry (MTR_asym). The result indicate that employing segmented saturation techniques with optimized reordered center-out k-space filling technology can effectively mitigate artifacts caused by scalp fat and enhance the accuracy of MTR_asym values. 

Key words: magnetic resonance imaging (MRI), chemical exchange saturation transfer (CEST), fat artifact, segmented acquisition, k-space reordering