title: The microstructure of white matter in male to female transsexuals before cross-sex hormonal treatment. A DTI study.
abstract: 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.
  
  
  METHODS
  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.
authors.affiliation: Clinical Institute of Neuroscience, Hospital Clínic, Barcelona, Spain.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Rametti
authors.forename: Beatriz
authors.initials: B
authors.lastname: Carrillo
authors.forename: Esther
authors.initials: E
authors.lastname: Gómez-Gil
authors.forename: Carme
authors.initials: C
authors.lastname: Junque
authors.forename: Leire
authors.initials: L
authors.lastname: Zubiarre-Elorza
authors.forename: Santiago
authors.initials: S
authors.lastname: Segovia
authors.forename: Ángel
authors.initials: Á
authors.lastname: Gomez
authors.forename: Antonio
authors.initials: A
authors.lastname: Guillamon
mesh_terms: D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000473:pathology; D002540:Cerebral Cortex / Q000187:drug effects / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D004967:Estrogens / Q000008:administration & dosage*; D005260:Female; D006179:Gyrus Cinguli / Q000187:drug effects / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects* / Q000473:pathology; D009434:Neural Pathways / Q000187:drug effects* / Q000473:pathology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000473:pathology; D012016:Reference Values; D012727:Sex Characteristics; D057829:Gender-Affirming Procedures; D014189:Transsexualism / Q000473:pathology*; D055815:Young Adult
chemical_list: D004967:Estrogens