title: Factors affecting the chemical exchange saturation transfer of Creatine as assessed by 11.7 T MRI.
abstract: Chemical exchange saturation transfer (CEST) is a new contrast enhancement approach for imaging exogenous or endogenous substances such as creatine (Cr), amide protons, and glutamate in the human body. An increase in field strength is beneficial for CEST imaging because of the increased chemical shift and longer longitudinal relaxation time (T1). In high-field magnetic resonance imaging (MRI), establishing and evaluating the CEST effect is important for optimizing the magnetization transfer (MT) saturation radio frequency (RF) pulses. In this study, the CEST effect on Cr was evaluated at different concentrations in pH phantoms by appropriately selecting MT saturation RF pulses using 11.7 T MRI. The results showed that the CEST efficiency increased gradually with increasing applied saturation RF pulse power and that it was affected by the number of saturation RF pulses and their bandwidths. However, spillover effects were observed with higher saturation RF pulse powers. In conclusion, we successfully performed in vitro Cr CEST imaging under optimized conditions of MT saturation RF pulses.
authors.affiliation: Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan, saito@sahs.med.osaka-u.ac.jp.
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Saito
authors.forename: Yuki
authors.initials: Y
authors.lastname: Mori
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Tanki
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003287:Contrast Media / Q000737:chemistry*; D003401:Creatine / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D057054:Molecular Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D011522:Protons; D011846:Radio Waves
chemical_list: D003287:Contrast Media; D011522:Protons; D003401:Creatine