title: Placental perfusion and permeability: simultaneous assessment with dual-echo contrast-enhanced MR imaging in mice.
abstract: OBJECTIVE
  To assess placental perfusion and permeability in mice with magnetic resonance (MR) imaging.
  
  
  METHODS
  This study was conducted according to French law and National Institutes of Health recommendations for animal care. Twenty-two pregnant BALB/c mice were examined at 1.5 T with a single-section dual-echo fast spoiled gradient-echo sequence. Two injection protocols were used: monophasic injection (double the clinical dose of contrast agent) and biphasic injection (quadruple the clinical dose). Signal intensities (SIs) were measured in the maternal left ventricle, placenta, and fetus (n = 16). At these high gadolinium doses, a T2* effect correction was used. SIs were converted to gadolinium concentrations and were analyzed by using a three-compartment model. Quantitative microcirculation parameters were calculated. Results with the monophasic and biphasic protocols were compared, and final arterial concentrations determined with MR imaging were compared with those determined with atomic emission spectrophotometry by using the unpaired Student t test.
  
  
  RESULTS
  Perfusion and permeability parameters for monophasic and biphasic injections were similar: Mean placental blood flow was 180 mL/min/100 g, mean permeability surface coefficient from maternal placental to fetal placental compartment was 10.3 x 10(-4) sec(-1) +/- 6.81 (standard deviation), mean permeability surface coefficient from fetal placental to maternal placental compartment was 4.65 x 10(-4) sec(-1) +/- 4.37, and mean fractional volume of the maternal vascular placental compartment was 36.5% +/- 0.9. Placental (146 vs 105 micromol/L, P < .004) and fetal (33.3 vs 19.1 micromol/L, P < .001) gadolinium concentrations were higher with the biphasic than with the monophasic protocol. Arterial gadolinium concentrations at MR imaging did not differ significantly from those at spectrophotometry for the monophasic (P = .254) or biphasic (P = .776) injection protocol.
  
  
  CONCLUSIONS
  Placental perfusion and permeability can be measured in vivo by using high gadolinium doses and a dual-echo MR imaging sequence.
authors.affiliation: Université Paris Descartes, Faculté de Médecine, INSERM U494, Laboratory of Research in Imaging, site Necker, 156 rue de Vaugirard, 75015 Paris, France. fab.taillieu@noons.fr
authors.forename: Fabienne
authors.initials: F
authors.lastname: Taillieu
authors.forename: Laurent J
authors.initials: LJ
authors.lastname: Salomon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Siauve
authors.forename: Olivier
authors.initials: O
authors.lastname: Clément
authors.forename: Nathalie
authors.initials: N
authors.lastname: Faye
authors.forename: Daniel
authors.initials: D
authors.lastname: Balvay
authors.forename: Catherine
authors.initials: C
authors.lastname: Vayssettes
authors.forename: Guy
authors.initials: G
authors.lastname: Frija
authors.forename: Yves
authors.initials: Y
authors.lastname: Ville
authors.forename: Charles A
authors.initials: CA
authors.lastname: Cuenod
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine / Q000493:pharmacokinetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D010920:Placenta / Q000098:blood supply*; D011247:Pregnancy
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine