title: A Potential Magnetic Resonance Imaging Technique Based on Chemical Exchange Saturation Transfer for In Vivo γ-Aminobutyric Acid Imaging.
abstract: OBJECTIVE
  We developed a novel magnetic resonance imaging (MRI) technique based on chemical exchange saturation transfer (CEST) for GABA imaging and investigated the concentration-dependent CEST effect ofGABA in a rat model of brain tumor with blood-brain barrier (BBB) disruption.
  
  
  METHODS
  All MRI studies were performed using a 7.0-T Agilent MRI scanner. Z-spectra for GABA were acquired at 7.0 T, 37°C, and a pH of 7.0 using varying B1 amplitudes. CEST images of phantoms with different concentrations of GABA solutions (pH, 7.0) and other metabolites (glutamine, myoinositol, creatinine, and choline) were collected to investigate the concentration-dependent CEST effect of GABA and the potential contribution from other brain metabolites. CEST maps for GABA in rat brains with tumors were collected at baseline and 50 min, 1.5 h, and 2.0 h after the injection of GABA solution.
  
  
  RESULTS
  The CEST effect of GABA was observed at approximately 2.75 parts per million(ppm) downfield from bulk water, and this effect increased with an increase in the B1 amplitude and remained steady after the B1 amplitude reached 6.0 μT (255 Hz). The CEST effect of GABA was proportional to the GABA concentration in vitro. CEST imaging of GABA in a rat brain with a tumor and compromised BBB showed a gradual increase in the CEST effect after GABA injection.
  
  
  CONCLUSIONS
  The findings of this study demonstrate the feasibility and potential of CEST MRI with the optimal B1 amplitude, which exhibits excellent spatial and temporal resolutions, to map changes in GABA.
authors.affiliation: Department of Radiology, Affiliated Hospital, Jiangnan University, Wuxi, 214062, China.|Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Gen
authors.initials: G
authors.lastname: Yan
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Zhuozhi
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Meizhi
authors.initials: M
authors.lastname: Yi
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Nie
authors.affiliation: The Mental Health Center, Medical College of Shantou University, Shantou, China.
authors.forename: Handi
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Mathematics and Statistics, Hanshan Normal University, Chaozhou, 521041, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Xiao
authors.affiliation: Department of Medical Imaging, The 2nd Affiliated Hospital, Shantou University Medical College, Shantou, 515041, China.
authors.forename: Renhua
authors.initials: R
authors.lastname: Wu
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging / Q000378:metabolism; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D051381:Rats; D017207:Rats, Sprague-Dawley; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D005680:gamma-Aminobutyric Acid