title: A novel technique for fetal heart rate estimation from Doppler ultrasound signal.
abstract: BACKGROUND
  The currently used fetal monitoring instrumentation that is based on Doppler ultrasound technique provides the fetal heart rate (FHR) signal with limited accuracy. It is particularly noticeable as significant decrease of clinically important feature - the variability of FHR signal. The aim of our work was to develop a novel efficient technique for processing of the ultrasound signal, which could estimate the cardiac cycle duration with accuracy comparable to a direct electrocardiography.
  
  
  METHODS
  We have proposed a new technique which provides the true beat-to-beat values of the FHR signal through multiple measurement of a given cardiac cycle in the ultrasound signal. The method consists in three steps: the dynamic adjustment of autocorrelation window, the adaptive autocorrelation peak detection and determination of beat-to-beat intervals. The estimated fetal heart rate values and calculated indices describing variability of FHR, were compared to the reference data obtained from the direct fetal electrocardiogram, as well as to another method for FHR estimation.
  
  
  RESULTS
  The results revealed that our method increases the accuracy in comparison to currently used fetal monitoring instrumentation, and thus enables to calculate reliable parameters describing the variability of FHR. Relating these results to the other method for FHR estimation we showed that in our approach a much lower number of measured cardiac cycles was rejected as being invalid.
  
  
  CONCLUSIONS
  The proposed method for fetal heart rate determination on a beat-to-beat basis offers a high accuracy of the heart interval measurement enabling reliable quantitative assessment of the FHR variability, at the same time reducing the number of invalid cardiac cycle measurements.
authors: Department of Biomedical Signal Processing, Institute of Medical Technology and Equipment, Roosevelta 118, 41-800 Zabrze, Poland.
authors: Janusz
authors: J
authors: Jezewski
authors: Dawid
authors: D
authors: Roj
authors: Janusz
authors: J
authors: Wrobel
authors: Krzysztof
authors: K
authors: Horoba
mesh_terms: D000465:Algorithms; D004562:Electrocardiography / Q000379:methods; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D006334:Heart Function Tests / Q000379:methods*; D006340:Heart Rate, Fetal; D006801:Humans; D008991:Monitoring, Physiologic; D011247:Pregnancy; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D018608:Ultrasonography, Doppler / Q000379:methods*