title: Quantification of iron-labeled cells with positive contrast in mouse brains.
abstract: OBJECTIVE
  To quantify small amounts of iron-labeled cells in mouse brains with magnetic resonance imaging (MRI).
  
  
  METHODS
  Iron-labeled cells (from 500 to 7,500) were stereotaxically transplanted into the brain of living mice that were subsequently imaged with MRI at 4.7 T. We compared four quantitative methods: (1) T2 relaxometry, (2) T2* relaxometry, (3) the volume of the cloverleaf hypointense artifact generated on T2*-weighted images, and (4) the volume of the cloverleaf hyperintense artifact generated on positive contrast images.
  
  
  RESULTS
  The methods based on relaxometry, whether T2 or T2*, did not correlate with the number of injected cells. By contrast, those based on measurement of cloverleaf artifact volume, whether using negative or positive enhancement, showed a significant linear relationship for the given range of cells (R [0.92-0.95], p < 0.05).
  
  
  CONCLUSIONS
  T2* artifact volume imaging (negative or positive) appears promising for the quantification of magnetically labeled cells following focal injection in the brain.
authors: Université de Lyon, Lyon 1, Lyon, France.
authors: Jean-Christophe
authors: JC
authors: Brisset
authors: Monica
authors: M
authors: Sigovan
authors: Fabien
authors: F
authors: Chauveau
authors: Adrien
authors: A
authors: Riou
authors: Emilie
authors: E
authors: Devillard
authors: Virginie
authors: V
authors: Desestret
authors: Monique
authors: M
authors: Touret
authors: Serge
authors: S
authors: Nataf
authors: J
authors: J
authors: Honnorat
authors: Emmanuelle
authors: E
authors: Canet-Soulas
authors: Norbert
authors: N
authors: Nighoghossian
authors: Yves
authors: Y
authors: Berthezene
authors: Marlene
authors: M
authors: Wiart
mesh_terms: D000818:Animals; D016477:Artifacts; D001921:Brain / Q000166:cytology* / Q000378:metabolism*; D003287:Contrast Media / Q000378:metabolism*; D005260:Female; D005290:Ferric Compounds / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007501:Iron / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D007501:Iron