Table 1.

Quantitative results of HERCULES and PRESS (with respect to total creatine, tCr) for the GM-rich and WM-rich voxels; statistical assessment of GM-WM differences (two-tailed t- test, no correction for multiple comparison); coefficients of variation (CV) for HERCULES, the HERCULES single-spectrum fitting methods, and PRESS; and the fitting method that gave the lowest overall CV. Values in brackets denote standard deviations. All CV values are given in %.

		Asc	Asp	GABA+	GSH	Lac	NAA	NAAG	tCho	Gln	Glu	Ins
HERCULES	GM Met/tCr (SD)	0.171 (0.034)	0.237 (0.049)	0.293 (0.022)	0. 182 (0.028)	0.119 (0.017)	2.182 (0.261)	0.265 (0.077)	0.3G4 (0.057)	0.219 (0.1G2)	1.416 (0.125)	0.965 (0.076)
	CV HERCULES	20	21	8	16	14	12	29	19	46	9	8
	CV A-B+C-D	30	77	134	22	45	89	61	85	75	212	23
	CV A+B-C-D	177	131	14	31	165	14	28	57	35	55	66
	CV SUM	75	146	50	32	118	31	32	11	37	9	12
	WM Met/tCr (SD)	0.181 (0.034)	0.160 (0.071)	0.239 (0.049)	0.208 (0.029)	0.115 (0.021)	2.305 (0.211)	0.520 (0.095)	0.416 (0.088)	0.330 (0.076)	1.093 (0.117)	0.897 (0.138)
	CV HERCULES	19	45	20	14	18	9	18	21	23	11	15
	CV A-B+C-D	43	142	52	21	59	90	44	74	130	243	24
	CV A+B-C-D	143	83	20	36	149	27	58	74	40	63	141
	CV SUM	159	33	53	31	92	57	33	14	79	20	11
	p (GM vs. WM)	0.531	0.019*	0.007**	0.071	0.664	0.295	<0.001***	0.007**	0.027*	<0.001***	0.202
PRESS	GM Met/tCr (SD)	0.168 (0.068)	0.399 (0.112)	0.212 (0.075)	0.305 (0.056)	0.264 (0.068)	1.215 (0.106)	0.362 (0.048)	0.250 (0.016)	0.022 (0.048)	1.285 (0.140)	0.595 (0.170)
	CV	41	28	35	18	26	9	13	6	223	11	29
	WM Met/tCr (SD)	0.261 (0.100)	0.391 (0.127)	0.121 (0.107)	0.277 (0.056)	0.195 (0.075)	1.291 (0.114)	0.418 (0.084)	0.282 (0.019)	0.005 (0.014)	1.001 (0.153)	0.677 (0.105)
	CV	38	33	88	20	38	9	20	7	316	15	16
	p (GM vs. WM)	0.030*	0.893	0.050*	0.275	0.051	0.149	0.093	0.001**	0.295	<0.001***	0.221
MEAN CV	HERCULES	19	33	14	15	16	11	24	20	35	10	12
	A-B+C-D	37	110	93	22	52	90	53	80	103	228	24
	A+B-C-D	160	107	17	34	157	21	43	66	38	59	104
	SUM	117	90	52	32	105	44	33	13	58	15	12
	PRESS	40	31	62	19	32	9	17	7	270	13	23
	Lowest CV	HERC	PRESS	HERC	HERC	HERC	PRESS	PRESS	PRESS	HERC	HERC	HERC

^*P < 0.05;

^**P < 0.01;

^***P < 0.001