title: Screening for fetal spina bifida at the 11-13-week scan using three anatomical features of the posterior brain.
abstract: OBJECTIVE
  To evaluate the contribution of examination of specific anatomical features of the fetal posterior brain on mid-sagittal first-trimester ultrasound examination to the early detection of open spina bifida.
  
  
  METHODS
  Four independent observers reviewed a series of 260 mid-sagittal first-trimester ultrasound images from 52 cases of open spina bifida and 208 normal fetuses. The following analysis was performed by each reviewer for each image: Herman score calculation, intracranial translucency score (CFEF-IT) calculation and determination of presence or absence of three anatomical criteria: intracranial translucency (IT), caudal displacement of the brainstem and cisterna magna. The sensitivity and the false-positive rate for spina bifida detection were calculated for each of the latter three criteria. A secondary analysis was performed on the subset of images achieving a Herman score ≥ 7.
  
  
  RESULTS
  The highest detection rate for spina bifida was achieved by non-visualization of the cisterna magna, with associated sensitivity of 50-73% and 39-76%, respectively, for all images and for the subset of images achieving a Herman score ≥ 7. Posterior shift of the brainstem achieved the highest detection rate (86%), but for a single reviewer only. The level of variation in performance between observers was also greatest for this sign. Absence of IT was associated with a lower detection rate for all observers. Overall, an abnormal posterior brain presenting at least one of these three criteria was associated with a detection rate ranging from 50 to 90%.
  
  
  CONCLUSIONS
  In the detection of spina bifida, non-visualization of the cisterna magna achieved the best screening performance. Both non-visualization of the IT and posterior shift of the brainstem were associated with acceptable but lower detection rates. A prospective evaluation of changes in the posterior brain is needed to allow assessment of the most pertinent criteria for first-trimester screening for spina bifida.
authors.affiliation: Collège Français d'Echographie Foetale (CFEF), Paris, France; Polyclinique Bordeaux Nord Aquitaine, Department of Women Imaging, Bordeaux, France.
authors.forename: R
authors.initials: R
authors.lastname: Mangione
authors.forename: F
authors.initials: F
authors.lastname: Dhombres
authors.forename: N
authors.initials: N
authors.lastname: Lelong
authors.forename: S
authors.initials: S
authors.lastname: Amat
authors.forename: F
authors.initials: F
authors.lastname: Atoub
authors.forename: S
authors.initials: S
authors.lastname: Friszer
authors.forename: B
authors.initials: B
authors.lastname: Khoshnood
authors.forename: J-M
authors.initials: JM
authors.lastname: Jouannic
mesh_terms: D001921:Brain / Q000196:embryology*; D001933:Brain Stem / Q000196:embryology / Q000648:ultrastructure; D002946:Cisterna Magna / Q000000981:diagnostic imaging / Q000196:embryology; D004453:Echoencephalography; D005260:Female; D006801:Humans; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016137:Spina Bifida Cystica / Q000000981:diagnostic imaging*; D016216:Ultrasonography, Prenatal / Q000379:methods
keywords: first trimester; intracranial translucency; posterior brain; prenatal diagnosis; spina bifida; ultrasound