Effect of irregular wall surface in models of carotid bifurcations on doppler spectra

Krzysztof Kałużyński , Liepsch D.

Abstract

The properties of ultrasonic Doppler spectra recorded in models of carotid bifurcations with irregular surface were studied. The lesion irregularity (ulceration) increases risk of cerebral embolism and such study is of interest for the assessment of such risk. Silicone rubber models of normal and stenosed bifurcations with smooth and irregular wall and a model in which the severe irregularity was replaced with a stenosis of the same height were studied. Physiological flow was simulated. Laser and ultrasonic Doppler velocity data were recorded. Averaged spatial velocity distribution were computed from the LDA data. The ultrasonic Doppler spectral parameters analysed were: turbulence intensity and spectral broadening indices, coefficient of skewness.In non-stenosed models the velocity distribution in the vicinity of the irregular surface located in the sinus was shifted towards the inner wall and the disturbance zone in the centre differred among models. Precise evaluation of spectral changes required referring to the LDA data. In the severe irregularity stenosed models observed were (with respect to smooth model):- a reduced flow zone (irregularity located at the outer wall), seen in the Doppler spectra as the lack of cyclic evolution, spectrum in lower frequency range.- a flow recirculation zone (irregularity located at the inner wall), seen in Doppler spectra as negative frequencies.- altered values of skewness and turbulence intensity;- the effect of irregularity differred from that of extra stenosis of the same height.Conclusion: Lesion irregularity in stenosed carotid bifurcation models results in reduced flow or recirculation zones downstream the irregular site, which can be seen in the corresponding Doppler spectra.
Author Krzysztof Kałużyński IMIB
Krzysztof Kałużyński,,
- The Institute of Metrology and Biomedical Engineering
, Liepsch D.
Liepsch D.,,
-
Journal seriesEuropean Journal of Ultrasound
Issue year1998
Vol7
No1001
Pages6-6
Publication size in sheets0.3
ConferenceEuroson Congress of EFSUMB, Tours, Francja
DOIDOI:10.1016/S0929-8266(97)80125-5
URL http://www.sciencedirect.com/science/article/pii/S0929826697801255?via%3Dihub
Languageen angielski
Score (nominal)0
Citation count*0 (2016-05-19)
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