title: The lung to thorax transverse area ratio has a linear correlation with the observed to expected lung area to head circumference ratio in fetuses with congenital diaphragmatic hernias.
abstract: OBJECTIVE
  The purpose of this study was to clarify the relationship between the lung to thorax transverse area ratio (L/T ratio) and the observed to expected lung area to head circumference ratio (O/E LHR), based on the results of a nationwide Japanese survey conducted in 2011, and to evaluate the compatibility of these prognostic predictors of fetal CDH.
  
  
  METHODS
  Two hundred and forty-two prenatally diagnosed isolated CDH patients born between 2006 and 2010 were included in the present analysis. A regression analysis was conducted to investigate the relationship between the L/T ratio and the O/E LHR based on 191 simultaneous measurements of these parameters in 120 patients.
  
  
  RESULTS
  The linear regression equation between the L/T ratio and the O/E LHR was: L/T ratio=0.0233+(0.00222×O/E LHR), (R=0.847, p<0.0001). According to this equation, 25% of the O/E LHR, the cut-off value used in the fetal intervention for CDH, was equivalent to an L/T ratio of 0.08, a commonly accepted cut-off value for identifying the most severe cases of fetal CDH.
  
  
  CONCLUSIONS
  As there is a positive correlation between the L/T ratio and the O/E LHR, these two parameters proved to be used interchangeably according to the linear regression equation.
authors.affiliation: Department of Pediatric Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. Electronic address: usui@pedsurg.med.osaka-u.ac.jp.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Usui
authors.affiliation: Department of Pediatric Surgery, Hyogo College of Medicine, Hyogo, Japan.
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Okuyama
authors.affiliation: Division of Surgery, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kanamori
authors.affiliation: Department of Pediatric Surgery, Kyushu University, Fukuoka, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Nagata
authors.affiliation: Center for Maternal-Neonatal Care, Nagoya University Hospital, Nagoya, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hayakawa
authors.affiliation: Department of Pediatric Cardiology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Inamura
authors.affiliation: Division of Neonatology, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Pediatric Surgery, Kyushu University, Fukuoka, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Taguchi
mesh_terms: D002508:Cephalometry / Q000379:methods*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000453:epidemiology; D005500:Follow-Up Studies; D005865:Gestational Age; D065630:Hernias, Diaphragmatic, Congenital / Q000175:diagnosis / Q000196:embryology* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000196:embryology*; D008176:Lung Volume Measurements; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012372:ROC Curve; D012189:Retrospective Studies
keywords: Congenital diaphragmatic hernia; Predictive parameter; Prenatal diagnosis; Prognostic factor; Pulmonary hypoplasia