MRI of Glutamate Modulation In-Vivo

Kejia Cai¹, Mohammad Haris¹, Anup Singh¹, Feliks Kogan¹, Walter R.T. Witschey¹, Prianka Waghray¹, Joel H. Greenberg², Hari Hariharan¹, John A. Detre², Ravinder Reddy¹

Glutamate (Glu) is the major neurotransmitter for fast excitatory synaptic transmission in central nervous system (CNS). Traditional magnetic resonance spectroscopy (MRS) for detection of Glu generally provides poor spatial and temporal resolution. This study demonstrates that Glu exhibits a pH-dependent chemical exchange saturation transfer (CEST) effect (GluCEST) in a concentration dependent manner. Glu modulation via intravenous injection in a rat brain tumor model resulted in clear elevation of GluCEST. Future studies using this approach may provide new insights into Glu function and demonstrate its potential as a biomarker for CNS disorders.