Hye-Young Heo1,2, Dong-Hoon Lee1, Yi Zhang1, Xuna Zhao1, Shanshan Jiang1, and Jinyuan Zhou1,2
1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States
Amide proton transfer (APT) imaging is a
novel chemical exchange saturation transfer (CEST)-based MRI modality that can
detect various endogenous mobile proteins and peptides in tissue, such as those
in the cytoplasm. The APT quantification results depend on the CEST metrics,
which is undesirable. In this study, four CEST metrics: (i) CEST ratio (CESTR),
(ii) CESTR normalized with the reference value (CESTRnr), (iii)
inverse Z-spectrum-based (MTRRex), and (iv) apparent
exchange-related relaxation (AREX), were compared using five-pool Bloch
equation-based simulations with varied RF saturation powers and magnetic field
strength, and in an in vivo rat tumor
study at 4.7 T.
