title: Characterizing the mesencephalon using susceptibility-weighted imaging.
abstract: OBJECTIVE
  The mesencephalon is involved in a number of human neurodegenerative disorders and has been typically imaged with T1-, T2- and T2*-weighted methods. Our aim was to collect high-contrast susceptibility-weighted imaging (SWI) data to differentiate among and within the basic mesencephalic structures: namely, the red nucleus, substantia nigra, and crus cerebri.
  
  
  METHODS
  High-resolution SWI, 3D T1-weighted, and T2-weighted data were collected to study contrast in the mesencephalon at 1.5T and 4T. Contrast between structures was calculated for SWI high-pass (HP)-filtered-phase, T1 gradient-echo, and spin-echo T2-weighted data.
  
  
  RESULTS
  SWI HP-filtered-phase data revealed similar contrast for the red nucleus and substantia nigra when compared with T2-weighted imaging. However, SWI was able to show structures within the red nucleus, substantia nigra, and medial geniculate body that were invisible on T2-weighted imaging. T1-weighted imaging, on the other hand, did not reveal measurable contrast for any of the structures of interest. SWI HP-filtered-phase data at 4T agreed well with india ink-stained cadaver brain studies, which appear to correlate with capillary density.
  
  
  CONCLUSIONS
  With SWI, it is possible to create better anatomic images of the mesencephalon, with improved contrast compared with conventional T1- or T2-weighted sequences.
authors.affiliation: Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Manova
authors.forename: C A
authors.initials: CA
authors.lastname: Habib
authors.forename: A S
authors.initials: AS
authors.lastname: Boikov
authors.forename: M
authors.initials: M
authors.lastname: Ayaz
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: W M
authors.initials: WM
authors.lastname: Kirsch
authors.forename: D K
authors.initials: DK
authors.lastname: Kido
authors.forename: E M
authors.initials: EM
authors.lastname: Haacke
mesh_terms: D000328:Adult; D005829:Geniculate Bodies / Q000033:anatomy & histology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008636:Mesencephalon / Q000033:anatomy & histology*; D008875:Middle Aged; D011712:Pyramidal Tracts / Q000033:anatomy & histology; D012012:Red Nucleus / Q000033:anatomy & histology; D013378:Substantia Nigra / Q000033:anatomy & histology; D055815:Young Adult