title: Fetal magnetic resonance imaging: exposure times and functional outcomes at preschool age.
abstract: BACKGROUND
  Fetal magnetic resonance imaging (MRI) has been routinely used as a noninvasive diagnostic tool for more than a decade; however, there is a paucity of follow-up studies examining the effects of prenatal exposure to 1.5-T MRI on developmental outcome.
  
  
  OBJECTIVE
  The objective of this study was to assess the safety of 1.5-T fetal MRI by evaluating functional outcomes of preschool children who were exposed in utero.
  
  
  METHODS
  In the context of a prospective observational study, healthy pregnant women underwent a 1.5-T MRI study using single-shot fast spin echo (SSFSE) sequences during the second or third trimester of pregnancy. The study was approved by the institutional review board at our institution, and written informed consent was obtained from all study participants. MRI scanning times were recorded, and prenatal/postnatal clinical data were collected prospectively. Functional outcomes were assessed using the Vineland Adaptive Behavior Scale (VABS), a widely used, norm-referenced and psychometrically sound functional assessment.
  
  
  RESULTS
  We studied 72 healthy pregnant women, who underwent fetal MRI at a mean gestational age of 30.5 ± 3.1 weeks. The cohort of fetuses was composed of 43% females, and 18 fetuses were scanned during the second trimester. All fetuses were born at term with appropriate birth weights (3.54 ± 0.5 kg) for gestational age. Mean age at follow-up testing was 24.5 ± 6.7 months. All children had age-appropriate scores in the communication, daily living, socialization and motor skills subdomains of the VABS (z-scores, P > 0.05). Furthermore, all children passed their newborn otoacoustic emission test and had normal hearing at preschool age. MRI study duration and exposure time to radio frequency waves and SSFSE sequences were not associated with adverse functional outcomes or hearing impairment.
  
  
  CONCLUSIONS
  Prenatal exposure to 1.5-T MRI during the second or third trimester of pregnancy in a cohort of healthy fetuses is not associated with disturbances in functional outcomes or hearing impairment at preschool age.
authors.affiliation: Institute for Biomedical Sciences, George Washington University, Washington, DC, USA.|Advanced Pediatric Brain Imaging Research Laboratory, Departments of Diagnostic Imaging and Radiology, Children's National Health System, 111 Michigan Ave. NW, Washington, DC, 20010, USA.
authors.forename: Marine
authors.initials: M
authors.lastname: Bouyssi-Kobar
authors.affiliation: Fetal and Transitional Medicine, Children's National Health System, Washington, DC, USA.
authors.forename: Adré J
authors.initials: AJ
authors.lastname: du Plessis
authors.affiliation: Department of Radiology, Children's Hospital Boston and Harvard Medical School, Boston, MA, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Robertson
authors.affiliation: Advanced Pediatric Brain Imaging Research Laboratory, Departments of Diagnostic Imaging and Radiology, Children's National Health System, 111 Michigan Ave. NW, Washington, DC, 20010, USA. climpero@childrensnational.org.|Fetal and Transitional Medicine, Children's National Health System, Washington, DC, USA. climpero@childrensnational.org.
authors.forename: Catherine
authors.initials: C
authors.lastname: Limperopoulos
mesh_terms: D002652:Child Behavior / Q000502:physiology*; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006330:Heart Defects, Congenital / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D013997:Time Factors
keywords: Development; Exposure; Fetus; Magnetic resonance imaging; Outcome; Safety