Placental perfusion MR imaging with contrast agents in a mouse model.
OBJECTIVE
To quantitatively analyze placental perfusion by using magnetic resonance (MR) imaging with contrast agents in a mouse model.


METHODS
Study was conducted according to French law and in full compliance with National Institutes of Health recommendations for animal care. Thirty-six pregnant Balb/c mice at 16 days of gestation were injected intravenously with either a conventional or macromolecular gadolinium chelate, and 1.5-T single-section T1-weighted two-dimensional fast spoiled gradient-echo sequential MR imaging was then performed for 14 minutes. Images were analyzed qualitatively, and parametric map analysis was performed in the resultant 25 mice included in the study. Signal intensity was measured in maternal left ventricle (input function), placenta, and fetus on all images. After converting signal intensity into contrast agent tissue concentrations, a three-compartment model was developed with compartmental and numeric modeling software. Placental perfusion was calculated for conventional (n = 12) and macromolecular (n = 13) gadolinium chelates. Finally, placental and fetal gadolinium concentrations were assayed by means of atomic emission spectrophotometry (n = 15). Perfusion values and placental and fetal gadolinium concentrations for conventional and macromolecular chelates were compared by using an unpaired t test.


RESULTS
Based on a constant transfer parameter, estimated placental perfusion did not differ between procedures with conventional and macromolecular gadolinium chelates (0.99 mL/min/g +/- 0.5 [standard deviation] and 1.28 mL/min/g +/- 0.6, respectively, P = .22). Likewise, mean placental gadolinium concentrations did not differ after injection of conventional and macromolecular chelates. In contrast, mean fetal gadolinium concentration was 9.83 micromol/L after conventional chelate injection and below detection limit after macromolecular chelate injection.


CONCLUSIONS
Placental perfusion can be calculated by using dynamic contrast-enhanced MR imaging, as shown in this mouse model.
Salomon
Laurent J
LJ
Laboratoire de Recherche en Imagerie, INSERM U494, Faculté de Médecine Necker, Université Paris 5, 156 rue de Vaugirard, 75015 Paris, France.
Siauve
Nathalie
N
Balvay
Daniel
D
Cuénod
Charles A
CA
Vayssettes
Catherine
C
Luciani
Alain
A
Frija
Guy
G
Ville
Yves
Y
Clément
Olivier
O
D000818:Animals; D003287:Contrast Media; D005260:Female; D006571:Heterocyclic Compounds; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine; D051379:Mice; D008807:Mice, Inbred BALB C; D009942:Organometallic Compounds; D010920:Placenta / Q000033:anatomy & histology / Q000098:blood supply*; D011247:Pregnancy
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine; C435266:contrast agent P792