The microstructure of white matter in male to female transsexuals before cross-sex hormonal treatment. A DTI study

J Psychiatr Res. 2011 Jul;45(7):949-54. doi: 10.1016/j.jpsychires.2010.11.007. Epub 2010 Dec 30.


Background: Diffusion tensor imaging (DTI) has been shown to be sensitive in detecting white matter differences between sexes. Before cross-sex hormone treatment female to male transsexuals (FtM) differ from females but not from males in several brain fibers. The purpose of this paper is to investigate whether white matter patterns in male to female (MtF) transsexuals before commencing cross-sex hormone treatment are also more similar to those of their biological sex or whether they are more similar to those of their gender identity.

Method: DTI was performed in 18 MtF transsexuals and 19 male and 19 female controls scanned with a 3 T Trio Tim Magneton. Fractional anisotropy (FA) was performed on white matter of the whole brain, which was spatially analyzed using Tract-Based Spatial Statistics.

Results: MtF transsexuals differed from both male and female controls bilaterally in the superior longitudinal fasciculus, the right anterior cingulum, the right forceps minor, and the right corticospinal tract.

Conclusions: Our results show that the white matter microstructure pattern in untreated MtF transsexuals falls halfway between the pattern of male and female controls. The nature of these differences suggests that some fasciculi do not complete the masculinization process in MtF transsexuals during brain development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / drug effects*
  • Brain / pathology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / pathology
  • Diffusion Magnetic Resonance Imaging*
  • Dominance, Cerebral / physiology
  • Estrogens / administration & dosage*
  • Female
  • Gyrus Cinguli / drug effects
  • Gyrus Cinguli / pathology
  • Humans
  • Image Processing, Computer-Assisted*
  • Male
  • Nerve Fibers / drug effects*
  • Nerve Fibers / pathology
  • Neural Pathways / drug effects*
  • Neural Pathways / pathology
  • Pyramidal Tracts / drug effects
  • Pyramidal Tracts / pathology
  • Reference Values
  • Sex Characteristics
  • Sex Reassignment Procedures*
  • Transsexualism / pathology*
  • Young Adult


  • Estrogens