TABLE II:
Metabolite concentrations in institutional units (I.U.) relative to the reference water signal and quantification error estimates by LCModel (Cramér-Rao lower bound, %) in each brain lobe and tissue type. The values are calculated as the average (standard deviation) across the healthy volunteers who were imaged by 3D ECCENTRCIC at 3.4 mm isotropic with (9min:20s acquisition time). The two bottom rows in the table present the SNR and FWHM mean (standard deviation) values. The last column shows the percentage of voxels inside the brain and FoV that meet the criteria of acceptable quality: CRLB < 20%, FWHM < 0.07ppm, SNR > 5.
| Mean across volunteers (Standard deviation) | Frontal | Limbic | Parietal | Occipital | Temporal | usable voxels mean % (std) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| WM | GM | WM | GM | WM | GM | WM | GM | WM | GM | ||
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| tCre [I.U.] | 3.34 ( 0.34 ) | 3.84 ( 0.04 ) | 3.22 ( 0.35 ) | 4.46 ( 0.28 ) | 3.30 ( 0.28 ) | 3.95 ( 0.28 ) | 3.31 ( 0.30 ) | 3.39 ( 0.19 ) | 3.09 ( 0.25 ) | 3.81 ( 0.19 ) | |
| tCre CRLB [%] | 3.25 ( 0.24 ) | 3.54 ( 0.41 ) | 3.38 ( 0.31 ) | 3.18 ( 0.30 ) | 3.21 ( 0.33 ) | 3.26 ( 0.26 ) | 3.45 ( 0.62 ) | 3.64 ( 0.62 ) | 3.42 ( 0.37 ) | 3.33 ( 0.26 ) | 73.3 (3.3) |
|
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| NAA [I.U.] | 4.16 ( 0.98 ) | 4.51 ( 0.66 ) | 4.07 ( 1.01 ) | 5.38 ( 0.90 ) | 4.31 ( 0.96 ) | 4.84 ( 0.88 ) | 4.33 ( 0.98 ) | 4.18 ( 0.85 ) | 3.91 ( 0.84 ) | 4.35 ( 0.73 ) | |
| NAA CRLB [%] | 3.13 ( 0.34 ) | 3.55 ( 0.64 ) | 3.26 ( 0.33 ) | 3.07 ( 0.36 ) | 2.86 ( 0.26 ) | 3.05 ( 0.37 ) | 3.30 ( 0.54 ) | 3.63 ( 0.64 ) | 3.32 ( 0.39 ) | 3.32 ( 0.34 ) | 73.0 (3.5) |
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| Ins [I.U.] | 3.49 ( 0.52 ) | 3.51 ( 0.35 ) | 3.65 ( 0.60 ) | 4.28 ( 0.48 ) | 3.73 ( 0.66 ) | 3.58 ( 0.29 ) | 3.74 ( 0.65 ) | 3.27 ( 0.57 ) | 3.56 ( 0.65 ) | 3.39 ( 0.51 ) | |
| Ins CRLB [%] | 5.33 ( 0.64 ) | 6.04 ( 0.94 ) | 5.29 ( 0.52 ) | 5.36 ( 0.42 ) | 5.16 ( 0.42 ) | 5.63 ( 0.52 ) | 5.38 ( 0.48 ) | 5.84 ( 0.50 ) | 5.34 ( 0.33 ) | 5.68 ( 0.40 ) | 73.0 (3.5) |
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| GPC+PCh [I.U.] | 1.03 ( 0.10 ) | 0.93 ( 0.05 ) | 1.10 ( 0.10 ) | 1.24 ( 0.08 ) | 1.06 ( 0.11 ) | 0.95 ( 0.09 ) | 0.94 ( 0.12 ) | 0.79 ( 0.06 ) | 0.99 ( 0.07 ) | 0.98 ( 0.12 ) | |
| GPC+PCh CRLB [%] | 3.63 ( 0.34 ) | 4.24 ( 0.59 ) | 3.46 ( 0.31 ) | 3.56 ( 0.27 ) | 3.56 ( 0.29 ) | 3.97 ( 0.33 ) | 4.13 ( 0.57 ) | 4.59 ( 0.64 ) | 3.68 ( 0.29 ) | 3.94 ( 0.25 ) | 73.5 (3.3) |
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| Glu [I.U.] | 3.86 ( 0.53 ) | 4.50 ( 0.29 ) | 3.72 ( 0.49 ) | 5.24 ( 0.46 ) | 3.86 ( 0.39 ) | 4.61 ( 0.39 ) | 3.80 ( 0.36 ) | 3.82 ( 0.38 ) | 3.50 ( 0.35 ) | 4.29 ( 0.44 ) | |
| Glu CRLB [%] | 4.51 ( 0.51 ) | 5.01 ( 0.85 ) | 4.72 ( 0.59 ) | 4.37 ( 0.47 ) | 4.31 ( 0.53 ) | 4.48 ( 0.55 ) | 4.82 ( 1.14 ) | 5.22 ( 1.32 ) | 4.80 ( 0.74 ) | 4.71 ( 0.64 ) | 72.8 (3.8) |
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| Gln [I.U.] | 0.89 ( 0.06 ) | 1.24 ( 0.25 ) | 0.83 ( 0.06 ) | 1.33 ( 0.16 ) | 0.80 ( 0.16 ) | 1.08 ( 0.26 ) | 0.87 ( 0.22 ) | 0.91 ( 0.21 ) | 0.80 ( 0.09 ) | 1.07 ( 0.22 ) | |
| Gln CRLB [%] | 15.93 ( 2.45 ) | 14.81 ( 2.22 ) | 17.72 ( 2.68 ) | 14.38 ( 2.48 ) | 17.92 4.78 ) | 16.22 ( 3.24 ) | 18.99 5.14 ) | 18.77 ( 4.11 ) | 18.30 ( 2.95 ) | 16.45 ( 2.60 ) | 56.3 (4.6) |
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| GABA [I.U.] | 1.34 ( 0.09 ) | 1.48 ( 0.29 ) | 1.34 ( 0.10 ) | 1.79 ( 0.37 ) | 1.37 ( 0.14 ) | 1.58 ( 0.30 ) | 1.33 ( 0.18 ) | 1.37 ( 0.18 ) | 1.21 ( 0.16 ) | 1.39 ( 0.32 ) | |
| GABA CRLB [%] | 8.68 ( 1.10 ) | 9.61 ( 1.51 ) | 8.86 ( 1.50 ) | 8.52 ( 1.74 ) | 8.54 ( 2.08 ) | 8.78 ( 1.76 ) | 9.48 ( 2.34 ) | 9.90 ( 2.22 ) | 9.60 ( 2.16 ) | 9.52 ( 2.09 ) | 68.3 (1.5) |
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| GSH [I.U.] | 1.07 ( 0.24 ) | 1.22 ( 0.05 ) | 1.11 ( 0.26 ) | 1.45 ( 0.20 ) | 1.10 ( 0.20 ) | 1.17 ( 0.07 ) | 1.05 ( 0.18 ) | 1.00 ( 0.09 ) | 1.02 ( 0.17 ) | 1.14 ( 0.12 ) | |
| GSH CRLB [%] | 8.20 ( 0.88 ) | 8.77 ( 1.15 ) | 8.29 ( 0.93 ) | 7.96 ( 0.79 ) | 8.04 ( 1.00 ) | 8.43 ( 0.87 ) | 9.12 ( 2.01 ) | 9.80 ( 1.90 ) | 8.65 ( 1.23 ) | 8.81 ( 1.17 ) | 71.5 (3.1) |
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| NAAG [I.U.] | 0.82 ( 0.14 ) | 0.39 ( 0.12 ) | 0.90 ( 0.13 ) | 0.49 ( 0.17 ) | 0.96 ( 0.17 ) | 0.34 ( 0.13 ) | 0.78 ( 0.16 ) | 0.41 ( 0.12 ) | 0.76 ( 0.11 ) | 0.35 ( 0.10 ) | |
| NAAG CRLB [%] | 14.11 ( 4.10 ) | 19.02 ( 5.07 ) | 12.43 ( 3.87 ) | 17.35 ( 6.07 ) | 12.01 ( 3.14 ) | 18.03 ( 5.15 ) | 15.51 ( 5.08 ) | 19.40 ( 6.62 ) | 15.36 ( 5.01 ) | 20.13 ( 6.40 ) | 45.3 (11.6) |
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| SNR | 24.64 ( 4.41 ) | 23.67 ( 3.84 ) | 22.92 ( 4.50 ) | 24.53 ( 4.02 ) | 25.64 ( 4.82 ) | 24.73 ( 4.17 ) | 22.48 ( 6.13 ) | 21.32 ( 5.56 ) | 22.07 ( 4.23 ) | 22.40 ( 3.37 ) | ∅ |
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| FWHM [Hz] | 11.43 ( 0.91 ) | 12.09 ( 0.77 ) | 11.28 ( 1.15 ) | 11.13 ( 1.13 ) | 10.21 0.79 ) | 11.02 ( 0.84 ) | 11.64 ( 0.91 ) | 12.33 ( 1.04 ) | 12.26 ( 1.23 ) | 12.38 ( 1.22 ) | ∅ |