Brain changes detected by functional magnetic resonance imaging and spectroscopy in patients with Crohn's disease

Table 2 Metabolites for magnetic resonance spectroscopy and their functions in normal adult human brain[66]

Metabolite	Chemical shift (ppm)	Concentration range (mmol/kgww)	Functions
NAA	2.02	7.9-16.6 (average 10.3)	An osmolite, a storage form of aspartate, a precursor of NAAG, a marker of neuronal density
GABA	3.01	1.3-1.9	A primary inhibitory neurotransmitter
tCho	3.20	0.9-2.5	An essential nutrient that is required for synthesis of the neurotransmitter acetylcholine, and of phosphatidylcholine, a major constituent of membranes
Cr	3.05	5.1-10.6	A concentration reference
Glu	2.04-2.35	6.0-12.5	An excitatory neurotransmitter
Gln	2.12-2.46	3.0-5.8	A precursor and storage form of glutamate
mI	3.56	3.8-8.1	An essential requirement for cell growth, and a storage form for glucose
Lac	1.33-1.35	0.4	The end product of anaerobic glycolysis

Cr: Creatine; GABA: γ-aminobutyric acid; Glu: Glutamate; Gln: Glutamine; Lac: Lactate; mI: Myo-inositol; mmol/kgww: mmol/kg of wet weight; NAA: N-acetylaspartate; ppm: Parts per million; tCho: Choline (total), free choline, glycerophosphorylcholine, and phosphorylcholine.