title: In vitro high-field magnetic resonance imaging-documented anatomy of a fetal myelomeningocele at 20 weeks' gestation. A contribution to the rationale of intrauterine surgical repair of spina bifida.
abstract: OBJECTIVE
  It remains uncertain if closure of a myelomeningocele at midgestation changes the neurological condition at birth in an infant born with spina bifida. The authors conducted a study to provide a detailed analysis of the morphology of the spinal cord with the myelomeningocele at the time fetal surgery usually is performed.
  
  
  METHODS
  The myelomeningocele of a 20-week-gestation-age fetus was examined, and data were compared with those obtained in a neurologically intact specimen of the same age. In vitro high-field 9.4-tesla magnetic resonance (MR) microscopy was used to examine the fetal material. High-field MR spectroscopy provided images in the three orthogonal planes with a resolution comparable with low-power optical microscopy. The authors observed that the fetal cord of the myelomeningocele specimen was tapered and tethered at S3-4 while the conus medullaris in the normal fetus reaches L-4. No neurulation defects were noted. The axial MR images clearly revealed the nonfusion of the mesodermal structures. The absence of neurulation defects suggests that at least in some cases of spina bifida the spinal cord initially is well developed but is damaged later on chemically and mechanically. This might be an argument in favor of intrauterine myelomeningocele repair. By 20 weeks' gestation, however, the deformation of the cord inside the myelomeningocele is severe. An optimization of the preoperative assessment by means of MR imaging therefore might be considered a valuable contribution to intrauterine surgery. The in vitro high-field MR microscopic findings of this study could be used as references for clinical intrauterine MR imaging.
  
  
  CONCLUSIONS
  The detailed in vitro high-field MR analysis of a 20-week-gestation-age fetus with spina bifida demonstrated that an improvement of the preoperative intrauterine imaging should be pursued to detect those cases without neurulation defects and with minimal deformation of the spinal cord.
authors.affiliation: Department of Anatomy, University of Limburg, Diepenbeek, Belgium. ebeu@snch.azm.nl
authors.forename: Emile A M
authors.initials: EA
authors.lastname: Beuls
authors.forename: Linda
authors.initials: L
authors.lastname: Vanormelingen
authors.forename: Jasper
authors.initials: J
authors.lastname: van Aalst
authors.forename: Marjan
authors.initials: M
authors.lastname: Vandersteen
authors.forename: Peter
authors.initials: P
authors.lastname: Adriaensens
authors.forename: Erwin M J
authors.initials: EM
authors.lastname: Cornips
authors.forename: Hans J S
authors.initials: HJ
authors.lastname: Vles
authors.forename: Jan
authors.initials: J
authors.lastname: Gelan
mesh_terms: D001139:Arnold-Chiari Malformation / Q000175:diagnosis / Q000196:embryology; D005315:Fetal Diseases / Q000175:diagnosis / Q000601:surgery; D005865:Gestational Age; D006801:Humans; D008279:Magnetic Resonance Imaging; D008591:Meningomyelocele / Q000175:diagnosis* / Q000196:embryology*; D013116:Spinal Cord / Q000473:pathology; D016135:Spinal Dysraphism / Q000196:embryology / Q000601:surgery