title: Prenatal diagnosis of fetal respiratory function: evaluation of fetal lung maturity using lung-to-liver signal intensity ratio at magnetic resonance imaging.
abstract: OBJECTIVE
  The purpose of this retrospective study is to determine the fetal lung-to-liver signal intensity ratio (LLSIR) on T2-weighted images for the prediction of neonatal respiratory outcome.
  
  
  METHODS
  One hundred ten fetuses who underwent magnetic resonance imaging (MRI) examination for various indications after 22 weeks of gestation participated in this study. LLSIR was measured as the ratio of signal intensities of the fetal lung and liver on T2-weighted images at MRI. We examined the changes of the ratio with advancing gestation and the relations between LLSIR and the presence of the severe respiratory disorder (SRD) after birth. The best cut-off value of the LLSIR to predict respiratory outcome after birth was calculated using receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  Lung-to-liver signal intensity ratio correlated significantly with advancing gestational age (R = 0.35, p < 0.001). The non-SRD group had higher LLSIR compared with the SRD group (2.15 ± 0.30 vs. 1.53 ± 0.40, p < 0.001). ROC curve analysis showed that fetuses with an LLSIR < 2.00 were more likely to develop SRD [sensitivity: 100%, 95% confidence interval (CI): 52-100%; specificity: 73%, 95% CI 54-88%].
  
  
  CONCLUSIONS
  The fetal LLSIR on T2-weighted images is an accurate marker to diagnose the fetal lung maturity.
authors.affiliation: Department of Obstetrics and Gynecology, Kanazawa Medical University, Uchinada, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Oka
authors.forename: Mosfequr
authors.initials: M
authors.lastname: Rahman
authors.forename: Chihaya
authors.initials: C
authors.lastname: Sasakura
authors.forename: Tomoo
authors.initials: T
authors.lastname: Waseda
authors.forename: Yukio
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Ryota
authors.initials: R
authors.lastname: Fujii
authors.forename: Satoru
authors.initials: S
authors.lastname: Makinoda
mesh_terms: D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D008099:Liver; D008168:Lung; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012129:Respiratory Function Tests; D012131:Respiratory Insufficiency / Q000175:diagnosis*; D012189:Retrospective Studies
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