European Radiology

, 18:822 | Cite as

Prospective navigator-echo-based real-time triggering of fetal head movement for the reduction of artifacts

  • H. BonelEmail author
  • K. A. Frei
  • L. Raio
  • M. Meyer-Wittkopf
  • L. Remonda
  • R. Wiest
Magnetic Resonance


The purpose of this study was to evaluate the neuroimaging quality and accuracy of prospective real-time navigator-echo acquisition correction versus untriggered intrauterine magnetic resonance imaging (MRI) techniques. Twenty women in whom fetal motion artifacts compromised the neuroimaging quality of fetal MRI taken during the 28.7 ± 4 week of pregnancy below diagnostic levels were additionally investigated using a navigator-triggered half-Fourier acquired single-shot turbo-spin echo (HASTE) sequence. Imaging quality was evaluated by two blinded readers applying a rating scale from 1 (not diagnostic) to 5 (excellent). Diagnostic criteria included depiction of the germinal matrix, grey and white matter, CSF, brain stem and cerebellum. Signal-difference-to-noise ratios (SDNRs) in the white matter and germinal zone were quantitatively evaluated. Imaging quality improved in 18/20 patients using the navigator echo technique (2.4 ± 0.58 vs. 3.65 ± 0.73 SD, p < 0.01 for all evaluation criteria). In 2/20 patients fetal movement severely impaired image quality in conventional and navigated HASTE. Navigator-echo imaging revealed additional structural brain abnormalities and confirmed diagnosis in 8/20 patients. The accuracy improved from 50% to 90%. Average SDNR increased from 0.7 ± 7.27 to 19.83 ± 15.71 (p < 0.01). Navigator-echo-based real-time triggering of fetal head movement is a reliable technique that can deliver diagnostic fetal MR image quality despite vigorous fetal movement.


Magnetic resonance imaging Navigator Artifacts Motion Fetal 


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Copyright information

© European Society of Radiology 2007

Authors and Affiliations

  • H. Bonel
    • 1
    Email author
  • K. A. Frei
    • 2
  • L. Raio
    • 2
  • M. Meyer-Wittkopf
    • 2
  • L. Remonda
    • 3
  • R. Wiest
    • 3
  1. 1.Institute of Diagnostic, Interventional and Pediatric RadiologyUniversity Hospital Berne-Inselspital, FreiburgstrasseBernSwitzerland
  2. 2.Women‘s’ HospitalUniversity of BerneBernSwitzerland
  3. 3.Institute of Diagnostic and Interventional Neuroradiology (DIN), InselspitalUniversity of BerneBernSwitzerland

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