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.