Table II.
Gray/white calibration factors and ICCs of volumes of interest between the different research sites
| Site (Code) | ICC | Cerebrum | ||||||
|---|---|---|---|---|---|---|---|---|
| Intracranium | Total brain | Cerebellum | Lateral ventricles | Third ventricle | GM ICC | WM ICC | f gw | |
| Utrecht, reference (U0) | — | — | — | — | — | — | — | 0.960 |
| London (L)a | 1.00 | 0.99 | 0.99 | 1.00 | 0.85 | 0.91 | 0.92 | 0.980 |
| Heidelberg (H)a | — | 0.96d | 0.92 | 0.96 | 0.21 | 0.74 | 0.78 | 1.026 |
| Jena (J)a | — | 0.97 | 0.95 | 0.99 | 0.81 | 0.93 | 0.95 | 0.970 |
| U0, L, H, J overall | — | 0.98 | 0.96 | 0.98 | 0.42 (0.84e) | 0.86 | 0.90 | — |
| Utrecht, repeated 2 (U2)b | 1.00 | 1.00 | 0.99 | 0.99 | 0.92 | 0.91 | 1.00 | — |
| Helsinki (F)c | — | 0.99 | 0.96 | 0.96 | 0.93 | 0.84 | 0.99 | 0.996 |
a
ICCs with respect to U0 (Subjects c1–c6).
b
ICCs with respect to U1 (Subjects c1–c5).
c
ICCs with respect to U1 (Subjects c1–c4).
d
After calibration (f lb = 0.89); without calibration (default f lb = 0.73) ICC = 0.80.
e
With the Heidelberg volumes excluded from the ICC calculation.
ICC, intraclass correlation; GM, gray matter; WM, white matter.