Comparisons of MR imaging volume data in different age groups
| Variables | 20–49 y | 50–86 y | P Values | ||
|---|---|---|---|---|---|
| Mean | SD | Mean | SD | ||
| Intracranial (mL) | 1367.3 | 147.4 | 1314.8 | 152.6 | .22 |
| GM (mL) | 717.8 | 96.8 | 626.1 | 84.3 | .001 |
| WM (mL) | 499.9 | 73.7 | 445.3 | 56.0 | .003 |
| % GM | 52.5 | 4.1 | 47.6 | 3.4 | <.0001 |
| % WM | 36.6 | 4.0 | 34.0 | 3.9 | .02 |
| GM/WM | 1.5 | 0.3 | 1.4 | 0.2 | .54 |