A novel technique for fetal heart rate estimation from Doppler ultrasound signal

Abstract

BackgroundThe 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.MethodsWe 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.ResultsThe 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.ConclusionsThe 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.

Doppler ultrasound compared with electrocardiogram and pulse oximetry cardiac triggering: A pilot study

“…Heart rate detection using DUS is primarily used in prenatal care for monitoring fetal heart rate . Such periodic signals are commonly analyzed using autocorrelation but do not necessarily have real time performance and accuracy for cardiac triggering.…”

Comparison of the effect of different sampling modes on computer analysis of cardiotocograms

“…Therefore, the fact that the quantification of accelerations and decelerations are different, together with the relatively small size of the dataset, may explain the fact that 4 Hz did not exhibit a significant influence on the number of presented decelerations. Previous works analyzed the effect of using internal or external monitoring in the computation of FHR indices [8] including the development of techniques for the improvement of the accuracy of the FHR signal acquired externally [11,13]. The present work focused on the comparison of commercially available different sampling frequencies of FHR signals, acquired using a fetal scalp electrode, which is the mode that provides the FHR signal with better accuracy.…”

A Novel Technique for Fetal Heart Rate Estimation Based on Ensemble Learning

“…Voicu et al (2010) used an ultrasonic multi-channel Doppler system by modifying ACF and proposed a new time and frequency estimator for the audio domain, and thus the miss rate of FHR has reduced to 5%. Jezewski et al (2011) achieved a high accuracy of fetal cardiac intervals measurement by adopting dynamic adjustment of autocorrelation window, adaptive autocorrelation peak detection and the determination method of the beat-to-beat interval, making it possible to reliably and quantitatively evaluate the FHR variability. Marzbanrad et al (2014) proposed an automated estimation of fetal cardiac intervals from a DUS signal based upon a unique combination of empirical mode decomposition (EMD) and hybrid support vector machine-hidden Markov model(SVM/HMM).…”