Functional imaging of the nonhuman primate Placenta with endogenous blood XXXX level-dependent contrast.

@entity2608 @entity26 @entity9243 @entity7672
PURPOSE: To characterize spatial patterns of T2* in the placenta of the @entity2608 ( @entity2608 ), to correlate these patterns with placental perfusion determined using dynamic contrast-enhanced MRI (DCE-MRI), and to evaluate the potential for using the blood @entity26 level-dependent effect to quantify placental perfusion without the use of exogenous contrast reagent. METHODS: MRI was performed on three pregnant @entity2608 at gestational day 110. Multiecho spoiled gradient echo measurements were used to compute maps of T2*. Spatial maxima in these maps were compared with foci of early enhancement determined by DCE-MRI. RESULTS: Local maxima in T2* maps were strongly correlated with spiral arteries identified by @entity9243 -MRI, with mean spatial separations ranging from 2.34 to 6.11   mm in the three animals studied. Spatial patterns of R2* (   =   1/ T2*) within individual placental lobules can be quantitatively analyzed using a simple model to estimate fetal arterial @entity7672 concentration [Hbo,f] and a parameter viPS/  , reflecting @entity26 transport to the fetus. Estimated mean values of [Hbo,f] ranged from 4.25   mM to 4.46   mM, whereas viPS/   ranged from 2.80   *   10(5) cm(-3) to 1.61   *   10(6) cm(-3) . CONCLUSIONS: Maternal spiral arteries show strong spatial correlation with foci of extended T2* observed in the primate placenta. A simple model of @entity26 transport accurately describes the spatial dependence of R2* within placental lobules and enables assessment of placental function and oxygenation without requiring administration of an exogenous contrast reagent. Magn Reson Med, 2015.    2015 Wiley Periodicals, Inc.
