Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653866
Title: An experimental and theoretical investigation of flow measurement by Doppler ultrasound
Author: Li, Shaofeng
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1995
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Abstract:
The aim of this thesis is to combine experimental and theoretical investigations of the sources of error in flow measurement techniques which use the Doppler principle and to look for possible ways to improve the accuracy. Computer models were developed in this thesis to simulate the Doppler spectrum. Results from the computer models were carefully compared with the experimental data. The effect of factors including geometrical spectral broadening, type and size of the transducer, focusing, depth of the vessel, beam-vessel angle misalignment of the beam and vessel, reflection and refraction at vessel wall were analysed using these models. Experiments showed that the errors in the diameter measurement were significant. Non-linear propagation has no significant effect on the Doppler measurement. It was confirmed experimentally that the mean velocity of pulsatile flow could be estimated by half of the maximum velocity averaged over an integral number of cardiac cycles. It was suggested that the geometrical spectral broadening and transit time spectral broadening were not the same effect as generally believed and should be treated separately. A detailed study of the flow phantom was also made prior to the investigation of the factors resulting in errors. Possible improvements of the accuracy of volumetric flow measurement were sought during these studies. It was found that a half pulse length correction in the diameter measurement can significantly improve the accuracy of the cross-sectional area estimation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.653866  DOI: Not available
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