Placental perfusion and permeability: simultaneous assessment with dual-echo contrast-enhanced MR imaging in mice.
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.
Taillieu
Fabienne
F
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
Salomon
Laurent J
LJ
Siauve
Nathalie
N
Clément
Olivier
O
Faye
Nathalie
N
Balvay
Daniel
D
Vayssettes
Catherine
C
Frija
Guy
G
Ville
Yves
Y
Cuenod
Charles A
CA
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
D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine