title: Quantification of spatial consistency in the Talairach and Tournoux stereotactic atlas.
abstract: BACKGROUND
  The Talairach-Tournoux (TT) atlas is one of the most prevalent brain atlases. Although its spatial inconsistencies were reported earlier, there has been no systematic quantification of them across the entire atlas, which is addressed here.
  
  
  METHODS
  The consistency of the TT atlas, defined as uniformity of labeling across all three orthogonal atlas orientations, is calculated and presented as maps. It is analyzed in function of discrepancy measuring spatial offset in labeling.
  
  
  RESULTS
  The TT atlas has 27.4% consistency and 37.7% inconsistency. The most consistent structure is the thalamus (85.7% consistency, 5.4% inconsistency). The consistency of the basal ganglia is good. For 3-mm discrepancy, the inconsistency of major subcortical gray matter structures is very low: 0% (globus pallidus medial and putamen), 0.7% (thalamus), 2.2% (globus pallidus lateral), 4.8% (hippocampus) and 4.9% (caudate nucleus). The inconsistency of all subcortical structures is relatively high (16.8%), caused by a very high inconsistency of white matter tracts. The consistency of stereotactic targets is 69.2% (GPi), 50.0% (STN) and 42.9% (VPL). The overall TT consistency increases by 20% for 1-mm discrepancy, constantly grows by 10% for 2-4-mm discrepancy and slows down to 3% for 5-6-mm discrepancy.
  
  
  CONCLUSIONS
  This work enhances our understanding of the TT atlas and its variable spatial consistency. It is helpful in using multiple atlas orientations simultaneously. It also may be useful in atlas interpolation and construction of a fully consistent 3D atlas. As the consistency of the main stereotactic targets is medium, the use of the TT atlas in stereotactic procedures requires a great deal of care and understanding of its limitations.
authors.affiliation: Biomedical Imaging Lab, Agency for Science Technology and Research, 30 Biopolis Street, 07-01, Matrix, Singapore 138671. wieslaw@sbic.a-star.edu.sg
authors.forename: Wieslaw L
authors.initials: WL
authors.lastname: Nowinski
authors.forename: A
authors.initials: A
authors.lastname: Thirunavuukarasuu
mesh_terms: D000716:Anatomy, Artistic / Q000592:standards*; D000886:Anthropometry / Q000379:methods; D001271:Atlases as Topic; D001921:Brain / Q000033:anatomy & histology* / Q000601:surgery*; D001931:Brain Mapping / Q000592:standards*; D003198:Computer Simulation / Q000592:standards; D016208:Databases, Factual; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008953:Models, Anatomic; D012016:Reference Values; D015203:Reproducibility of Results; D012984:Software; D013238:Stereotaxic Techniques / Q000592:standards*