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Analysis of the Auditory Perception of Ultrasound Doppler Signals to Improve Pregnancy Risk Assessment

Ewerlof, M.; Thuring, Ann LU ; Marsal, Karel LU and Jansson, Tomas LU (2011) 15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC 2011) In 15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (IFMBE Proceedings) 34. p.81-84
Abstract
In high-risk pregnancies, the transport of oxygen and nutrients from maternal to fetal blood via the placenta is often impaired. To assess the risk, pulsed Doppler ultrasound (US) is used to evaluate the flow velocity waveform in the umbilical artery with the pulsatility index (PI), which is derived from the velocity envelope of the Doppler power spectrum. However, simply listening to the Doppler signal can indicate to an experienced sonographer that the type of the blood flow is worse than the PI suggests. This is however dependent on the operator's experience and it may be difficult to estimate what influences the subjective judgement. Motivated by the description of the Doppler sounds by an experienced operator (AT) as having a... (More)
In high-risk pregnancies, the transport of oxygen and nutrients from maternal to fetal blood via the placenta is often impaired. To assess the risk, pulsed Doppler ultrasound (US) is used to evaluate the flow velocity waveform in the umbilical artery with the pulsatility index (PI), which is derived from the velocity envelope of the Doppler power spectrum. However, simply listening to the Doppler signal can indicate to an experienced sonographer that the type of the blood flow is worse than the PI suggests. This is however dependent on the operator's experience and it may be difficult to estimate what influences the subjective judgement. Motivated by the description of the Doppler sounds by an experienced operator (AT) as having a "timbre", this study describes an analysis of Doppler sounds in search for an index or method with capacity to better evaluate the blood flow in the umbilical artery in high-risk pregnancies. A test was designed, where synthetically produced Doppler sounds with various spectral contents were played together with a variable sinusoidal sound signal. The task for the five test persons was to match the frequency of the sinusoidal signal to the Doppler sounds. The tests indicated that the human ear is most sensitive to the lower frequencies of Doppler sounds. An analysis of prerecorded sounds showed a difference in the lower frequencies of a sound considered to emanate from the umbilical blood flow of healthy fetuses with normally functioning placenta as compared to a pathological one. This might explain the difference between the sounds experienced by an operator. As a suggestion to extract more information than the maximum envelope, the minimum frequency envelope was extracted from pre-recorded clinical sounds. Based on the pilot tests presented here, this shows to be a promising strategy. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
synthetic Doppler signal, pulsatility index, flow velocity waveform, umbilical artery blood flow
in
15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (IFMBE Proceedings)
editor
Dremstrup, Kim; Rees, Steve; ├ślgaard Jensen, Morten; ; and
volume
34
pages
81 - 84
publisher
Springer
conference name
15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC 2011)
external identifiers
  • wos:000308452500020
  • scopus:79959947561
ISSN
1680-0737
ISBN
978-3-642-21682-
DOI
10.1007/978-3-642-21683-1_20
language
English
LU publication?
yes
id
743fe765-40bb-4dcd-9bdd-79974c013c7d (old id 3470394)
date added to LUP
2013-02-25 12:25:56
date last changed
2017-10-08 03:55:46
@inproceedings{743fe765-40bb-4dcd-9bdd-79974c013c7d,
  abstract     = {In high-risk pregnancies, the transport of oxygen and nutrients from maternal to fetal blood via the placenta is often impaired. To assess the risk, pulsed Doppler ultrasound (US) is used to evaluate the flow velocity waveform in the umbilical artery with the pulsatility index (PI), which is derived from the velocity envelope of the Doppler power spectrum. However, simply listening to the Doppler signal can indicate to an experienced sonographer that the type of the blood flow is worse than the PI suggests. This is however dependent on the operator's experience and it may be difficult to estimate what influences the subjective judgement. Motivated by the description of the Doppler sounds by an experienced operator (AT) as having a "timbre", this study describes an analysis of Doppler sounds in search for an index or method with capacity to better evaluate the blood flow in the umbilical artery in high-risk pregnancies. A test was designed, where synthetically produced Doppler sounds with various spectral contents were played together with a variable sinusoidal sound signal. The task for the five test persons was to match the frequency of the sinusoidal signal to the Doppler sounds. The tests indicated that the human ear is most sensitive to the lower frequencies of Doppler sounds. An analysis of prerecorded sounds showed a difference in the lower frequencies of a sound considered to emanate from the umbilical blood flow of healthy fetuses with normally functioning placenta as compared to a pathological one. This might explain the difference between the sounds experienced by an operator. As a suggestion to extract more information than the maximum envelope, the minimum frequency envelope was extracted from pre-recorded clinical sounds. Based on the pilot tests presented here, this shows to be a promising strategy.},
  author       = {Ewerlof, M. and Thuring, Ann and Marsal, Karel and Jansson, Tomas},
  booktitle    = {15th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (IFMBE Proceedings)},
  editor       = {Dremstrup, Kim and Rees, Steve and ├ślgaard Jensen, Morten},
  isbn         = {978-3-642-21682-},
  issn         = {1680-0737},
  keyword      = {synthetic Doppler signal,pulsatility index,flow velocity waveform,umbilical artery blood flow},
  language     = {eng},
  pages        = {81--84},
  publisher    = {Springer},
  title        = {Analysis of the Auditory Perception of Ultrasound Doppler Signals to Improve Pregnancy Risk Assessment},
  url          = {http://dx.doi.org/10.1007/978-3-642-21683-1_20},
  volume       = {34},
  year         = {2011},
}