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. Author manuscript; available in PMC: 2008 Jun 13.
Published in final edited form as: Neuroimage. 2007 Mar 24;36(3):617–629. doi: 10.1016/j.neuroimage.2007.02.050

Table 5.

Means of diffusion signals and diffusivities at each shell.

shell 0 1 2 3 4 5
b-value (s/mm2) 0 375 1500 3375 6000 9375
WM Arithmetic mean 742 ± 197 587 ± 96 301 ± 58 169 ± 40 121 ± 33 97 ± 27
Geometric mean 742 ±197 583 ± 95 282 ± 57 142 ± 37 93 ± 27 72 ± 21
Da (10−6mm2/s) 609 ± 100 410 ± 63 203 ± 49 93 ± 29
Dg (10−6mm2/s) 656 ± 110 468 ± 76 246 ± 58 113 ± 41
GM Arithmetic mean 962 ± 373 727 ± 171 317 ± 95 122 ± 47 70 ± 36 60 ± 32
Geometric mean 962 ± 373 723 ± 170 307 ± 94 103 ± 42 53 ± 28 44 ± 24
Da (10−6mm2/s) 760 ± 153 600 ± 92 341 ± 78 122 ± 44
Dg (10−6mm2/s) 785 ± 161 657 ± 104 396 ± 89 143 ± 57

Da: the diffusivity calculated using a linear least squares fit of a monoexponential model on arithmetic means of three contiguous shells, i.e. shell 0–2, 1–3, 2–4 and 3–5.

Dg: the diffusivity calculated using geometric means of three contiguous shells. Whole brain WM and GM were segmented using Po map and FAST algorithm. The standard deviation is across whole brain ROI of one subject.