Cardiac output is often measured by indicator dilution techniques, usually based on dye or cold saline injections. Developments of more stable ultrasound contrast agents (UCA) are leading to new noninvasive indicator dilution methods. However, several problems concerning the interpretation of dilution curves as detected by ultrasound transducers have arisen. This paper presents a method for blood flow measurements based on UCA dilution. Dilution curves are determined by real-time densitometric analysis of the video output of an ultrasound scanner and are automatically fitted by the Local Density Random Walk model. A new fitting algorithm based on multiple linear regression is developed. Calibration, that is, the relation between videodensity and UCA concentration, is modelled by in vitro experimentation. The flow measurement system is validated by in vitro perfusion of SonoVue contrast agent. The results show an accurate dilution curve fit and flow estimation with determination coefficient larger than 0.95 and 0.99, respectively.
This article is part of the series Advances in Modality-Oriented Medical Image Processing.
Research Article Videodensitometric Methods for Cardiac Output Measurements
1 The Eindhoven Technical University, Electrical Engineering Faculty, Signal Processing Systems Department, Den Dolech 2, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
2 Catharina Hospital Eindhoven, Department of Anaesthesiology and Intensive Care, P.O. Box 1350, Eindhoven 5602 ZA, The Netherlands
EURASIP Journal on Advances in Signal Processing 2003, 2003:862083 doi:10.1155/S1110865703211185
The electronic version of this article is the complete one and can be found online at: http://asp.eurasipjournals.com/content/2003/5/862083
| Received: | 1 May 2002 |
| Revisions received: | 2 October 2002 |
| Published: | 14 April 2003 |
© 2003 Copyright © 2003 Hindawi Publishing Corporation
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