Table 2. Means and standard deviations for metabolite ratios and concentrations (mm) in healthy human brain (see Fig. 3 for definition of loci).

			Hippocampus
	1	2	3	4
Cr:NAA	0.79 ± 0.11	0.85 ± 0.06	0.89 ± 0.06	0.93 ± 0.16
Glutamate:NAA	0.62 ± 0.16	0.69 ± 0.08	0.64 ± 0.11	0.67 ± 0.24
NAA	10.2 ± 1.8	10.5 ± 1.1	8.9 ± 0.9	8.0 ± 1.8
Glutamate	6.7 ± 2.2	7.7 ± 1.3	6.0 ± 1.3	5.4 ± 1.7
Creatine	8.8 ± 1.6	9.9 ± 1.2	8.7 ± 1.0	8.4 ± 2.1
Choline	2.5 ± 0.5	3.9 ± 0.5	3.7 ± 0.6	3.5 ± 0.8
Percentage gray matter	62 ± 7	54 ± 5	48 ± 5	61 ± 5
Percentage CSF	21 ± 5	18 ± 6	7 ± 4	8 ± 3