title: Ex vivo delineation of placental angioarchitecture with the microbubble contrast agent Levovist.
abstract: OBJECTIVE
  The aim of this study was to delineate placental vasculature with the microbubble contrast agent Levovist (99.9% galactose and 0.1% palmitic acid; Schering AG, Berlin, Germany), with the ultimate goal of delineating placental vascular anatomy in utero.
  
  
  METHODS
  A placental lobule from each of 11 term human placentas was perfused on the fetal side of the circulation under physiologic conditions. Randomly assigned dose-concentration combinations of Levovist were administered through a chorionic artery into the corresponding placental lobule, and the resultant echoenhancement with power Doppler imaging was recorded for digital analysis. Interplacental variability was corrected for by averaging the results of three injections at each dose-concentration combination.
  
  
  RESULTS
  Echoenhancement was seen at all dose-concentration combinations in the injected lobule but not in adjacent control lobules. The three dose-concentration combinations that achieved optimal maximal integrated intensity and duration of action for both chorionic vessel and villus enhancement were 100 microL/kg of 400-mg/mL Levovist, 200 microL/kg of 400-mg/mL Levovist, and 400 microL/kg of 200-mg/mL Levovist.
  
  
  CONCLUSIONS
  Microbubble contrast injection into the fetal vasculature enabled power Doppler imaging echoenhancement both in chorionic vessels and within the villus tree. We speculate that fetal injection of contrast agent may be applied to the delineation of placental lesions or areas of interfetal transfusion, although its applicability will be hindered by the need for fetal blood sampling.
authors.affiliation: Centre for Fetal Care, Institute of Obstetrics and Gynaecology, Imperial College School of Medicine, Queen Charlotte's and Chelsea Hospital, London, United Kingdom.
authors.forename: M L
authors.initials: ML
authors.lastname: Denbow
authors.forename: R
authors.initials: R
authors.lastname: Eckersley
authors.forename: A W
authors.initials: AW
authors.lastname: Welsh
authors.forename: M J
authors.initials: MJ
authors.lastname: Taylor
authors.forename: R C
authors.initials: RC
authors.lastname: Carter
authors.forename: D O
authors.initials: DO
authors.lastname: Cosgrove
authors.forename: N M
authors.initials: NM
authors.lastname: Fisk
mesh_terms: D001808:Blood Vessels / Q000033:anatomy & histology; D003287:Contrast Media; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008863:Microspheres; D009994:Osmolar Concentration; D010477:Perfusion; D010920:Placenta / Q000098:blood supply* / Q000000981:diagnostic imaging; D011134:Polysaccharides / Q000008:administration & dosage; D011247:Pregnancy; D011897:Random Allocation; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508