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Effect of non-linearity in predicting doppler waveforms through a novel model

BACKGROUND: In pregnancy, the uteroplacental vascular system develops de novo locally in utero and a systemic haemodynamic & bio-rheological alteration accompany it. Any abnormality in the non-linear vascular system is believed to trigger the onset of serious morbid conditions like pre-eclampsia...

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Autores principales: Gayasen, Aman, Dua, Sunil Kumar, Sengupta, Amit, Nagchoudhuri, D
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2003
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC222923/
https://www.ncbi.nlm.nih.gov/pubmed/14561227
http://dx.doi.org/10.1186/1475-925X-2-16
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author Gayasen, Aman
Dua, Sunil Kumar
Sengupta, Amit
Nagchoudhuri, D
author_facet Gayasen, Aman
Dua, Sunil Kumar
Sengupta, Amit
Nagchoudhuri, D
author_sort Gayasen, Aman
collection PubMed
description BACKGROUND: In pregnancy, the uteroplacental vascular system develops de novo locally in utero and a systemic haemodynamic & bio-rheological alteration accompany it. Any abnormality in the non-linear vascular system is believed to trigger the onset of serious morbid conditions like pre-eclampsia and/or intrauterine growth restriction (IUGR). Exact Aetiopathogenesis is unknown. Advancement in the field of non-invasive doppler image analysis and simulation incorporating non-linearities may unfold the complexities associated with the inaccessible uteroplacental vessels. Earlier modeling approaches approximate it as a linear system. METHOD: We proposed a novel electrical model for the uteroplacental system that uses MOSFETs as non-linear elements in place of traditional linear transmission line (TL) model. The model to simulate doppler FVW's was designed by including the inputs from our non-linear mathematical model. While using the MOSFETs as voltage-controlled switches, a fair degree of controlled-non-linearity has been introduced in the model. Comparative analysis was done between the simulated data and the actual doppler FVW's waveforms. RESULTS & DISCUSSION: Normal pregnancy has been successfully modeled and the doppler output waveforms are simulated for different gestation time using the model. It is observed that the dicrotic notch disappears and the S/D ratio decreases as the pregnancy matures. Both these results are established clinical facts. Effects of blood density, viscosity and the arterial wall elasticity on the blood flow velocity profile were also studied. Spectral analysis on the output of the model (blood flow velocity) indicated that the Total Harmonic Distortion (THD) falls during the mid-gestation. CONCLUSION: Total harmonic distortion (THD) is found to be informative in determining the Feto-maternal health. Effects of the blood density, the viscosity and the elasticity changes on the blood FVW are simulated. Future works are expected to concentrate mainly on improving the load with respect to varying non-linear parameters in the model. Heart rate variability, which accounts for the vascular tone, should also be included. We also expect the model to initiate extensive clinical or experimental studies in the near future.
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spelling pubmed-2229232003-10-24 Effect of non-linearity in predicting doppler waveforms through a novel model Gayasen, Aman Dua, Sunil Kumar Sengupta, Amit Nagchoudhuri, D Biomed Eng Online Research BACKGROUND: In pregnancy, the uteroplacental vascular system develops de novo locally in utero and a systemic haemodynamic & bio-rheological alteration accompany it. Any abnormality in the non-linear vascular system is believed to trigger the onset of serious morbid conditions like pre-eclampsia and/or intrauterine growth restriction (IUGR). Exact Aetiopathogenesis is unknown. Advancement in the field of non-invasive doppler image analysis and simulation incorporating non-linearities may unfold the complexities associated with the inaccessible uteroplacental vessels. Earlier modeling approaches approximate it as a linear system. METHOD: We proposed a novel electrical model for the uteroplacental system that uses MOSFETs as non-linear elements in place of traditional linear transmission line (TL) model. The model to simulate doppler FVW's was designed by including the inputs from our non-linear mathematical model. While using the MOSFETs as voltage-controlled switches, a fair degree of controlled-non-linearity has been introduced in the model. Comparative analysis was done between the simulated data and the actual doppler FVW's waveforms. RESULTS & DISCUSSION: Normal pregnancy has been successfully modeled and the doppler output waveforms are simulated for different gestation time using the model. It is observed that the dicrotic notch disappears and the S/D ratio decreases as the pregnancy matures. Both these results are established clinical facts. Effects of blood density, viscosity and the arterial wall elasticity on the blood flow velocity profile were also studied. Spectral analysis on the output of the model (blood flow velocity) indicated that the Total Harmonic Distortion (THD) falls during the mid-gestation. CONCLUSION: Total harmonic distortion (THD) is found to be informative in determining the Feto-maternal health. Effects of the blood density, the viscosity and the elasticity changes on the blood FVW are simulated. Future works are expected to concentrate mainly on improving the load with respect to varying non-linear parameters in the model. Heart rate variability, which accounts for the vascular tone, should also be included. We also expect the model to initiate extensive clinical or experimental studies in the near future. BioMed Central 2003-09-18 /pmc/articles/PMC222923/ /pubmed/14561227 http://dx.doi.org/10.1186/1475-925X-2-16 Text en Copyright © 2003 Gayasen et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.
spellingShingle Research
Gayasen, Aman
Dua, Sunil Kumar
Sengupta, Amit
Nagchoudhuri, D
Effect of non-linearity in predicting doppler waveforms through a novel model
title Effect of non-linearity in predicting doppler waveforms through a novel model
title_full Effect of non-linearity in predicting doppler waveforms through a novel model
title_fullStr Effect of non-linearity in predicting doppler waveforms through a novel model
title_full_unstemmed Effect of non-linearity in predicting doppler waveforms through a novel model
title_short Effect of non-linearity in predicting doppler waveforms through a novel model
title_sort effect of non-linearity in predicting doppler waveforms through a novel model
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC222923/
https://www.ncbi.nlm.nih.gov/pubmed/14561227
http://dx.doi.org/10.1186/1475-925X-2-16
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