title: Magnetic resonance imaging of the active second stage of labour: proof of principle.
abstract: OBJECTIVE
  To prove that magnetic resonance imaging of foetal anatomy during the active second stage of vaginal delivery is feasible.
  
  
  METHODS
  Initially, five pregnant volunteers around the 30th week of gestation were examined in an open MRI. Based on the findings, one vaginal delivery was acquired under real-time imaging. To monitor the birth status during image acquisition, an MR-compatible wireless cardiotocography (CTG) system was built. Single-shot sequence parameters were optimised to compensate motion artefacts during labour.
  
  
  RESULTS
  Safety requirements to monitor the birth process under real-time MR imaging were met. High-resolution MR images were acquired immediately before and after delivery. In one patient, TSE single-shot cinematic sequences of the active second stage of labour were obtained. All sequences were adapted to tolerate movement of the mother and infant, as well as residual noise from the CTG. Furthermore, the MR imaging during labour showed only minor image artefacts.
  
  
  CONCLUSIONS
  CTG-monitored acquisition of MRI series during the active second stage of delivery is feasible. Image quality should allow various further studies to improve models for birth simulation as well as potential investigation of obstructed labour and obstetric complications.
authors.affiliation: Department of Radiology, Charité University Hospital, Charitéplatz 1, 10117 Berlin, Germany. felix.guettler@charite.de
authors.forename: F V
authors.initials: FV
authors.lastname: Güttler
authors.forename: A
authors.initials: A
authors.lastname: Heinrich
authors.forename: J
authors.initials: J
authors.lastname: Rump
authors.forename: M
authors.initials: M
authors.lastname: de Bucourt
authors.forename: B
authors.initials: B
authors.lastname: Schnackenburg
authors.forename: C
authors.initials: C
authors.lastname: Bamberg
authors.forename: B
authors.initials: B
authors.lastname: Hamm
authors.forename: U K
authors.initials: UK
authors.lastname: Teichgräber
mesh_terms: D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007748:Labor Stage, Second; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010865:Pilot Projects; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity