title: Reference ranges for 2-dimensional sonographic lung measurements in healthy fetuses: a longitudinal study.
abstract: OBJECTIVE
  The purpose of this study was to establish reference ranges for 2-dimensional sonographic measurements of fetal lungs from longitudinal data.
  
  
  METHODS
  A total of 214 fetal lung measurements were longitudinally evaluated in 62 healthy fetuses between 20 and 36 weeks' menstrual age. Both right and left lung areas were measured in the heart 4-chamber view using lung area tracing and axis diameter methods. Multilevel modeling was used to evaluate the expected values and variability with respect to menstrual age and to generate reference ranges for the lung area, lung-to-head ratio, quantitative lung index, and observed-to-expected lung-to-head ratio for both lungs.
  
  
  RESULTS
  The expected values varied with menstrual age for all parameters. Variance was menstrual age dependent for all parameters except the longest diameter area measurements and their lung-to-head ratios.
  
  
  CONCLUSIONS
  Models are presented for expected 2-dimensional sonographic lung size parameters and their variance as a function of menstrual age. These data have been used to generate age-specific reference ranges for both measurements and indices.
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Ingrid Schwach Werneck
authors.initials: IS
authors.lastname: Britto
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Edward
authors.initials: E
authors.lastname: Araujo Júnior
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Haleh
authors.initials: H
authors.lastname: Sangi-Haghpeykar
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Luiz Cláudio Silva
authors.initials: LC
authors.lastname: Bussamra
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Russell L
authors.initials: RL
authors.lastname: Deter
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Michael A
authors.initials: MA
authors.lastname: Belfort
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
authors.forename: Wesley
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.). ruano@bcm.edu rodrigoruano@hotmail.com.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ruano
mesh_terms: D000375:Aging / Q000502:physiology*; D001938:Brazil; D003198:Computer Simulation; D018568:Crown-Rump Length; D005260:Female; D005865:Gestational Age; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards*; D008137:Longitudinal Studies; D008168:Lung / Q000000981:diagnostic imaging* / Q000196:embryology*; D008297:Male; D008954:Models, Biological; D015233:Models, Statistical; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013781:Texas; D016216:Ultrasonography, Prenatal / Q000592:standards*
keywords: congenital diaphragmatic hernia; fetal lung; fetal lung area; lung-to-head ratio; obstetric ultrasound; prenatal diagnosis; pulmonary hypoplasia; sonography