title: Functional imaging of the nonhuman primate Placenta with endogenous blood oxygen level-dependent contrast.
abstract: To characterize spatial patterns of T2* in the placenta of the rhesus macaque (Macaca mulatta), to correlate these patterns with placental perfusion determined using dynamic contrast-enhanced MRI (DCE-MRI), and to evaluate the potential for using the blood oxygen level-dependent effect to quantify placental perfusion without the use of exogenous contrast reagent.
  
  
  
  MRI was performed on three pregnant rhesus macaques 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.
  
  
  
  Local maxima in T2* maps were strongly correlated with spiral arteries identified by DCE-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 oxyhemoglobin concentration [Hbo,f] and a parameter viPS/Φ, reflecting oxygen transport to the fetus. Estimated mean values of [Hbo,f] ranged from 4.25 mM to 4.46 mM, whereas viPS/Φ ranged from 2.80 × 105cm-3to 1.61 × 106cm-3.
  
  
  
  Maternal spiral arteries show strong spatial correlation with foci of extended T2* observed in the primate placenta. A simple model of oxygen 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 76:1551-1562, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Advanced Imaging Research Center, Oregon Health & Science University.|Utah Center for Advanced Imaging Research, University of Utah.
authors.forename: M C
authors.initials: MC
authors.lastname: Schabel
authors.affiliation: Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University.
authors.forename: V H J
authors.initials: VHJ
authors.lastname: Roberts
authors.affiliation: Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University.
authors.forename: J O
authors.initials: JO
authors.lastname: Lo
authors.affiliation: Division of Neuroscience, Oregon National Primate Research Center.
authors.forename: S
authors.initials: S
authors.lastname: Platt
authors.affiliation: Division of Neuroscience, Oregon National Primate Research Center.|Department of Behavioral Neuroscience, Oregon Health & Science University.
authors.forename: K A
authors.initials: KA
authors.lastname: Grant
authors.affiliation: Division of Diabetes, Obesity & Metabolism, Oregon Health & Science University.|Division of Developmental & Reproductive Sciences, Oregon National Primate Research Center.|Department of Obstetrics & Gynecology, Oregon Health & Science University.
authors.forename: A E
authors.initials: AE
authors.lastname: Frias
authors.affiliation: Advanced Imaging Research Center, Oregon Health & Science University.|Division of Neuroscience, Oregon National Primate Research Center.|Department of Behavioral Neuroscience, Oregon Health & Science University.
authors.forename: C D
authors.initials: CD
authors.lastname: Kroenke
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000378:metabolism; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D010920:Placenta / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000502:physiology*; D021041:Placental Circulation / Q000502:physiology*; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D010100:Oxygen
keywords: BOLD MRI; DCE-MRI; Placenta; Pregnancy