title: Acardiac twinning: High resolution three-dimensional reconstruction of a low resistance case.
abstract: BACKGROUND
  Acardiac twinning is a rare anomaly of monochorionic twin pregnancies. Acardiac fetuses lack a functional heart but are passively perfused by arterial blood from their pump co-twin. Although four acardiac morphological types have been classified, the various paths of anatomical and circulatory acardiac twin development, and the potential influence of acardiac size and perfusion flow as possible predictors of pump twin morbidity and mortality are poorly understood. This report presents the first high resolution three-dimensional reconstruction of the vasculature of an acardiac twin by cryomicrotome imaging.
  
  
  METHODS
  A small, approximately 7.5-cm-diameter ball-shaped acardius amorphous of 30 5/7 weeks had caused pump twin cardiac decompensation that necessitated an emergency cesarian section. The pump twin survived well. The acardiac body had a partially intact vascular system with large diameter arteries and veins and multiple zones that appeared devoid of perfusion. The three-dimensional reconstruction showed neither recognizable organ structures nor identifiable blood vessels except for the umbilical artery and vein.
  
  
  CONCLUSIONS
  Our case showed a small acardiac mass with large diameter vessels and consequential low outflow resistance that caused pump twin complications. This indicates that the development of a method that allows pump twin prognosis is likely more successful if based on the use of acardiac versus pump twin perfusion flows than on body volume ratios.
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Monique G J T B
authors.initials: MG
authors.lastname: van Lier
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden.
authors.forename: Enrico
authors.initials: E
authors.lastname: Lopriore
authors.affiliation: Department of Obstetrics, Leiden University Medical Center, Leiden.
authors.forename: Frank P H A
authors.initials: FP
authors.lastname: Vandenbussche
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Geert J
authors.initials: GJ
authors.lastname: Streekstra
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Siebes
authors.affiliation: Department of Pathology, University Medical Center and Wilhelmina Children's Hospital, Utrecht, The Netherlands.
authors.forename: Peter G J
authors.initials: PG
authors.lastname: Nikkels
authors.affiliation: Department of Obstetrics, Leiden University Medical Center, Leiden.
authors.forename: Dick
authors.initials: D
authors.lastname: Oepkes
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Martin J C
authors.initials: MJ
authors.lastname: van Gemert
authors.affiliation: Department of Biomedical Engineering and Physics, Academic Medical Center-University of Amsterdam, Amsterdam, The Netherlands.|Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jeroen P H M
authors.initials: JP
authors.lastname: van den Wijngaard
mesh_terms: D002585:Cesarean Section; D020285:Cryoelectron Microscopy; D004200:Diseases in Twins / Q000151:congenital / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005260:Female; D005333:Fetus; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008867:Microtomy; D011247:Pregnancy; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal
keywords: 3D reconstruction; TRAP sequence; acardiac twin; circulation; cryomicrotome; hypoxia