Open Access

Videodensitometric Methods for Cardiac Output Measurements

EURASIP Journal on Advances in Signal Processing20032003:862083

Received: 1 May 2002

Published: 14 April 2003


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.


contrast agents local density random walk ultrasound videodensitometry

Authors’ Affiliations

Electrical Engineering Faculty, Signal Processing Systems Department, The Eindhoven Technical University
Department of Anaesthesiology and Intensive Care, Catharina Hospital Eindhoven


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