Ex vivo delineation of placental angioarchitecture with the microbubble contrast agent Levovist

OBJECTIVE: The aim of this study was to delineate placental vasculature wit h the microbubble contrast agent Levovist (99.9% galactose and 0.1% palmiti c acid; Schering AG, Berlin, Germany), with the ultimate goal of delineatin g placental vascular anatomy in utero. STUDY DESIGN: A placental lobule from each of 11 term human placentas was p erfused an the fetal side of the circulation under physiologic conditions. Randomly assigned dose-concentration combinations of Levovist were administ ered through a chorionic artery into the corresponding placental lobule, an d the resultant echoenhancement with power Doppler imaging was recorded for digital analysis. Interplacental variability was corrected for by averagin g 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-co ncentration combinations that achieved optimal maximal integrated intensity and duration of action for both chorionic vessel and villus enhancement we re 100 mu L/kg of 400-mg/mL Levovist, 200 mu L/kg of 400-mg/mL Levovist, an d 400 mu L/kg of 200-mg/mL Levovist. CONCLUSION: Microbubble contrast injection into the fetal vasculature enabl ed power Doppler imaging echoenhancement both in chorionic vessels and with in 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 fe tal blood sampling.