Table 3.
Significant regional grey volume differences between groups (post hoc two-group comparisons).
| Comparison | Brain region | T1 | P2 | Size of cluster3 | Coordinates (x, y, z)4 |
|---|---|---|---|---|---|
| Whole-brain exploratory analysis | |||||
| Cisgender men > cisgender women | Paracentral lobule and SMC bilaterally and L precentral gyrus (BA 6) | 5.92 | 0.002 | 1383 | 0 −9 67 |
| Hormone-treated TW > cisgender women | L medial superior frontal gyrus, extending bilaterally to the SMC and paracentral lobule (BA 6) | 5.29 | 0.023 | 1994 | 0 −8 67 |
| Small-volume correction-based analyses | |||||
| Treatment-naïve TW < cisgender women | L Insula (BA 13) | 4.07 | 0.014 | 828 | −35 −16 13 |
| R Insula (BA 13) | 4.25 | 0.008 | 437 | 36 −9 12 | |
| Hormone-treated TW < cisgender men | L Insula (BA 13) | 4.01 | 0.012 | 67 | −36 5 −14 |
| L Insula (BA 13) | 3.79 | 0.031 | 60 | −42 −7 4 | |
| Hormone-treated TW < cisgender women | L Insula (BA 13) | 4.22 | 0.009 | 755 | −42 −10 6 |
| R Insula (BA 13) | 3.74 | 0.035 | 414 | 45 −4 3 | |
Notes: TW = transgender women with gender dysphoria diagnosis; SMC = supplementary motor cortex; BA = Brodmann area; L = left; R = right. 1T value (post hoc tests) for the voxel of maximal statistical significance within each cluster. 2Statistical significance after correction for multiple comparisons; inferences were made at the level of individual voxels (family-wise error correction) and a minimum extent threshold of 30 voxels. 3Total number of contiguous voxels in each region above an initial cut-off of Z > 3.09. 4MNI coordinates of the voxel of maximal statistical significance within each cluster.