title: New anatomical landmarks to study the relationship between fetal lung area and thoracic circumference by three-dimensional ultrasonography.
abstract: OBJECTIVE
  To evaluate the relation between total lung area (TLA) and thoracic circumference (TC) ratio by three-dimensional (3D) ultrasonography applying new anatomical landmarks as the fetal aorta and inferior angle of the scapula.
  
  
  METHODS
  A longitudinal prospective study was conducted with 56 uncomplicated pregnancies between 24 and 32 weeks of gestation. Polynomial regressions were used to evaluate the correlation between TC and gestational age (GA) as well as TC and estimated fetal weight (EFW). A simple linear regression was used to evaluate the correlation between TLA and Total thoracic area (TTA) and GA. The intraclass correlation coefficient (ICC) was used to assess the intra and interobserver variability.
  
  
  RESULTS
  127 examinations were performed. TC values ranged from 150 to 174 mm (mean 166 mm) at 24 weeks and 215-248 mm (mean 231 mm) at 32 weeks. The TLA/TC ratio ranged from a mean of 0.64 at 24 weeks (range 0.56-0.70) to 0.90 at 32 weeks gestation (range 0.79-1.01). The intraobserver variability using the ICC was of 0.919 for TC; 0.916 for TTA; 0.860 for right lung area (RLA) and 0.910 for left lung area (LLA). Interobserver reproducibility was with an ICC of 0.970 for TC; 0.984 for RLA and 0.910 for LLA.
  
  
  CONCLUSIONS
  Measurement of fetal TC and the relationship between TLA and TC by 3D-ultrasonography applying new anatomical landmarks shows good reproducibility and allows a new assessment of thoracic and lung growth.
authors.affiliation: Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo (FCMSCSP), São Paulo, SP, Brazil.
authors.forename: Ingrid Schwach Werneck
authors.initials: IS
authors.lastname: Britto
authors.forename: Giselle Darahem
authors.initials: GD
authors.lastname: Tedesco
authors.forename: Sandra Rejane Silva
authors.initials: SR
authors.lastname: Herbst
authors.forename: Luiz Cláudio Silva
authors.initials: LC
authors.lastname: Bussamra
authors.forename: Fernando Moreira
authors.initials: FM
authors.lastname: de Andrade
authors.forename: Edward
authors.initials: E
authors.lastname: Araujo Júnior
authors.forename: Luciano Marcondes Machado
authors.initials: LM
authors.lastname: Nardozza
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Ruano
authors.forename: Antonio Fernandes
authors.initials: AF
authors.lastname: Moron
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Aoki
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D047109:Fetal Development; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D021621:Imaging, Three-Dimensional; D016014:Linear Models; D008137:Longitudinal Studies; D008168:Lung / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000196:embryology*; D015588:Observer Variation; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D013909:Thorax / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000196:embryology*; D016216:Ultrasonography, Prenatal; D055815:Young Adult