title: High-resolution MRI and diffusion-weighted imaging of the human habenula at 7 tesla.
abstract: OBJECTIVE
  To investigate the feasibility of discriminating the habenula in human brain using high-resolution structural MRI and diffusion-weighted imaging at 7 Tesla (T).
  
  
  METHODS
  MRI experiments included a MP2RAGE and GRE sequence to acquire quantitative parameter maps of T1, T2*, and a calculated proton density map and the combined approach of zoomed and parallel imaging (ZOOPPA) to obtain dw images. Probabilistic tractography algorithms were used to identify multiple fiber orientations in submillimetre voxels, and constrained spherical deconvolution to resolve orientations in regions where fibers cross.
  
  
  RESULTS
  Maps of T1, T2*, and proton density showed high contrast of the human habenula. The lateral habenula and its commissure can be distinguished from medial habenula and adjacent tissue. DWI data with 0.7 mm isotropic resolution revealed that fiber populations differ in medial and lateral habenula and two major fiber bundles that connect habenular nuclei with forebrain structures and brainstem.
  
  
  CONCLUSIONS
  High resolution 7T MR imaging of the human habenula provides sufficient signal-to-noise and contrast to enable identification of the lateral and medial nuclei. In vivo high resolution DWI at 7T is able to distinguish between lateral and medial habenula, and to detect major fiber tracts that connect the habenula with other brain areas.
authors.affiliation: Department of Neurophysics, Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Strotmann
authors.forename: Robin M
authors.initials: RM
authors.lastname: Heidemann
authors.forename: Alfred
authors.initials: A
authors.lastname: Anwander
authors.forename: Marcel
authors.initials: M
authors.lastname: Weiss
authors.forename: Robert
authors.initials: R
authors.lastname: Trampel
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Robert
authors.initials: R
authors.lastname: Turner
mesh_terms: D000368:Aged; D000465:Algorithms; D002102:Cadaver; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D019262:Habenula / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 7T; diffusion-weighted imaging; habenula; structural MRI