title: Prospective study of intracranial translucency and the posterior brain in normal fetuses at the 11- to 13-week scan.
abstract: OBJECTIVE
  To evaluate the ability of sonographers to prospectively identify intracranial translucency and posterior brain structures at 11 to 13 weeks and to evaluate measurement reproducibility of brain stem and brain stem-occipital bone diameters on stored images.
  
  
  METHODS
  After specific training for intracranial translucency visualization, 10 nonphysician sonographers prospectively identified intracranial translucency at the 11- to 13-week scan, noting whether intracranial translucency was present, absent, or uncertain. If absent/uncertain, they documented the reason as spina bifida or an inadequate image (with reasons for the inadequate image). Measurements of brain stem and brain stem-occipital bone diameters were performed on stored images. Fifty randomly selected cases were reviewed for intraobserver and interobserver variability.
  
  
  RESULTS
  In 313 singleton pregnancies, the posterior brain including intracranial translucency was evaluated; 293 (93.6%) had known pregnancy outcomes. None had open spina bifida, but 7 had chromosomal or congenital abnormalities. In the remaining 286 normal fetuses, intracranial translucency was seen in 275 (96%) and uncertain in 11 (4%), due to inadequate images (top 3 reasons were fetal position [n = 8], obesity [n = 5], and retroverted uterus [n = 4]). Fetal position and gestational age were significantly associated with intracranial translucency visualization (P < .05). Intraobserver and interobserver agreement rates were moderate for measurements of brain stem diameter (intraclass correlation coefficients, 0.59 and 0.57) and substantial for brain stem-occipital bone diameter (intraclass correlation coefficients, 0.76 and 0.61). Bland-Altman analysis revealed negligible intraobserver and interobserver differences in brain stem and brain stem-occipital bone diameter measurements.
  
  
  CONCLUSIONS
  Intracranial translucency can be prospectively identified by trained sonographers in 96% of normal fetuses at 11 to 13 weeks. Measurements of brain stem and brain stem-occipital bone diameters are reproducible.
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.). kfong@mtsinai.on.ca.
authors: Katherine W
authors: KW
authors: Fong
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.).
authors: Jana
authors: J
authors: Dengler
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.).
authors: Ants
authors: A
authors: Toi
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.).
authors: Ravi J
authors: RJ
authors: Menezes
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.).
authors: Yasser
authors: Y
authors: Karimzad
authors: Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada (K.W.F., A.T., R.J.M.); Joint Department of Medical Imaging, Mount Sinai Hospital, University Health Network and Women's College Hospital, Toronto, Ontario, Canada (K.W.F., J.D., A.T., R.J.M., Y.K.); and Department of Obstetrics and Gynecology, Mount Sinai Hospital, Toronto, Ontario, Canada (N.O.).
authors: Nanette
authors: N
authors: Okun
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000196:embryology; D001931:Brain Mapping / Q000379:methods; D005260:Female; D006801:Humans; D008875:Middle Aged; D048208:Nuchal Translucency Measurement / Q000379:methods; D015588:Observer Variation; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult
keywords: brain stem; first-trimester screening; intracranial translucency; obstetric ultrasound; prenatal sonography; spina bifida