title: Reference range for the fetal intracranial translucency measurement between 11 and 14 + 2 weeks of gestation in a Brazilian population.
abstract: OBJECTIVE
  To establish a reference range for the fetal intracranial translucency (IT) measurement between 11 and 14 + 2 weeks in a Brazilian population.
  
  
  METHODS
  A retrospective cross-sectional study was performed with 199 low-risk singleton pregnancies during the first trimester ultrasound exam. The IT (fourth ventricle width) measurement was performed in a mid-sagittal view of fetal profile defined by two echogenic borders - the dorsal part of the brain stem anteriorly and the choroid plexus of the fourth ventricle posteriorly. Polynomial regression was used to obtain the best fit using fetal IT measurements and crown-rump length (CRL). Percentiles 5th, 50th and 95th were determined for each gestational age.
  
  
  RESULTS
  The mean of fetal IT ranged from 1.6 mm at CRL 45 to 2.0 mm at CRL 84 mm. A best fit curve was a first-degree polynomial regression: IT measurement = 1.001 + 0.0124 × CRL (R(2)=0.09).
  
  
  CONCLUSIONS
  Reference range for the fetal IT measurement between 11 and 14 + 2 weeks of gestation in a Brazilian population was established.
authors.affiliation: a Mario Palmério University Hospital, University of Uberaba (UNIUBE) , Uberaba , MG , Brazil .|b Radiologic Clinic of Uberaba (CRU) , Uberaba , MG , Brazil .
authors.forename: Alberto Borges
authors.initials: AB
authors.lastname: Peixoto
authors.affiliation: a Mario Palmério University Hospital, University of Uberaba (UNIUBE) , Uberaba , MG , Brazil .|b Radiologic Clinic of Uberaba (CRU) , Uberaba , MG , Brazil .
authors.forename: Taciana Mara
authors.initials: TM
authors.lastname: Caldas
authors.affiliation: a Mario Palmério University Hospital, University of Uberaba (UNIUBE) , Uberaba , MG , Brazil .
authors.forename: Larrisa Abu
authors.initials: LA
authors.lastname: Lasmar
authors.affiliation: c Department of Obstetrics and Gynecology , Ribeirão Preto Medical School, University of São Paulo (DGO-FMRP-USP) , Ribeirão Preto, SP , Brazil , and.
authors.forename: Wellington P
authors.initials: WP
authors.lastname: Martins
authors.affiliation: d Department of Obstetrics , Paulista School of Medicine - Federal University of São Paulo (EPM-UNIFESP) , São Paulo, SP , Brazil.
authors.forename: David Baptista
authors.initials: DB
authors.lastname: Pares
authors.affiliation: d Department of Obstetrics , Paulista School of Medicine - Federal University of São Paulo (EPM-UNIFESP) , São Paulo, SP , Brazil.
authors.forename: Edward
authors.initials: E
authors.lastname: Araujo Júnior
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil; D002552:Cerebral Ventricles / Q000000981:diagnostic imaging* / Q000196:embryology*; D003430:Cross-Sectional Studies; D018568:Crown-Rump Length; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D012016:Reference Values; D012044:Regression Analysis; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D055815:Young Adult
keywords: Brazilian population; first trimester; intracranial translucency; reference range; screening