title: MR-PET image coregistration for quantitation of striatal dopamine D2 receptors.
abstract: OBJECTIVE
  Our goal was to assess the utility of MR-PET image coregistration to quantify dopamine D2 receptors in striatum.
  
  
  METHODS
  Twenty-nine normal subjects were investigated with PET and [11C]raclopride and with MRI. D2 receptors were quantified using the ratio of the distribution volume in striatum to that in cerebellum. Measures obtained using regions selected directly from the PET images were compared with those obtained from MR images and then projected to coregistered PET images.
  
  
  RESULTS
  There were no differences between measures selected from the PET images (3.9 +/- 0.5) and those from the MR images (3.9 +/- 0.65). The values for these two measures were significantly correlated and corresponded to r = 0.9, p < 0.0001.
  
  
  CONCLUSIONS
  Regions of interest selected directly from PET images, where there is a large contrast between the region of interest and background, as for the case of dopamine D2 ligands, are almost identical to those obtained from coregistered MR images.
authors.affiliation: Medical Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Wang
authors.forename: N D
authors.initials: ND
authors.lastname: Volkow
authors.forename: A V
authors.initials: AV
authors.lastname: Levy
authors.forename: J S
authors.initials: JS
authors.lastname: Fowler
authors.forename: J
authors.initials: J
authors.lastname: Logan
authors.forename: D
authors.initials: D
authors.lastname: Alexoff
authors.forename: R J
authors.initials: RJ
authors.lastname: Hitzemann
authors.forename: D J
authors.initials: DJ
authors.lastname: Schyler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017448:Receptors, Dopamine D2 / Q000032:analysis*; D014055:Tomography, Emission-Computed
chemical_list: D017448:Receptors, Dopamine D2