title: Effect of antenatal corticosteroid treatment on the fetal lung: a magnetic resonance imaging study.
abstract: OBJECTIVE
  To investigate the effect of antenatal corticosteroid treatment on the fetal lung using magnetic resonance imaging.
  
  
  METHODS
  Prospective evaluation of 30 consecutive singleton pregnancies that received antenatal corticosteroid treatment (12 mg betamethasone i.m. on admission and 24 h later) because of threatened preterm birth. Fetal lungs were assessed using T2-weighted single-shot fast spin-echo images of a whole-body 1.5-T superconducting unit twice: less than 24 h and more than 48 h after the first course of betamethasone. Lung volumes and lung-liver signal-intensity ratios were compared between the two time points.
  
  
  RESULTS
  Nine patients had to be excluded from the analysis because they did not complete the study protocol as required. Ten female and 11 male fetuses with a gestational age between 23.4 and 32.6 weeks were included in the final analysis. The mean gestational age of included fetuses was 27.5 ± 2.8 weeks. Using a linear regression model, a significant influence of gestational age on ln fetal lung volume (r(2)=0.414; P<0.0001) and lung-liver signal-intensity ratios (r(2)=0.271, P<0.0001) was found. Between the two evaluated time points, a significant increase in lung-liver signal-intensity ratios (2.34 ± 0.72 vs. 3.22 ± 1.12, P<0.0001), but not in mean lung volumes (46.6 ± 20.7 cm(3) vs. 48.8 ± 16.0 cm(3) , P=0.292), was observed.
  
  
  CONCLUSIONS
  We demonstrate a significant increase in lung-liver signal-intensity ratios after antenatal corticosteroid treatment for induction of lung maturation which most likely reflects changing properties of the fetal lung parenchyma. This could potentially be useful in non-invasively assessing the effect of antenatal corticosteroid treatment on the lungs of fetuses at risk for preterm birth.
authors.affiliation: Department of Obstetrics and Feto-maternal Medicine, Medical University of Vienna, Vienna, Austria. maximilian.schmid@meduniwien.ac.at
authors.forename: M
authors.initials: M
authors.lastname: Schmid
authors.forename: G
authors.initials: G
authors.lastname: Kasprian
authors.forename: L
authors.initials: L
authors.lastname: Kuessel
authors.forename: A
authors.initials: A
authors.lastname: Messerschmidt
authors.forename: P C
authors.initials: PC
authors.lastname: Brugger
authors.forename: D
authors.initials: D
authors.lastname: Prayer
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D001623:Betamethasone / Q000627:therapeutic use*; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects* / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016014:Linear Models; D008168:Lung / Q000187:drug effects* / Q000196:embryology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies
chemical_list: D000305:Adrenal Cortex Hormones; D001623:Betamethasone