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Báo cáo hóa học: " Videodensitometric Methods for Cardiac Output Measurements"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Videodensitometric Methods for Cardiac Output Measurements | EURASIP Journal on Applied Signal Processing 2003 5 479-489 2003 Hindawi Publishing Corporation Videodensitometric Methods for Cardiac Output Measurements Massimo Mischi The Eindhoven Technical University Electrical Engineering Faculty Signal Processing Systems Department Den Dolech 2 P O. Box 513 5600 MB Eindhoven The Netherlands Email m.mischi@tue.nl Ton Kalker The Eindhoven Technical University Electrical Engineering Faculty Signal Processing Systems Department Den Dolech 2 P O. Box 513 5600 MB Eindhoven The Netherlands Email ton.kalker@ieee.org Erik Korsten Catharina Hospital Eindhoven Department of Anaesthesiology and Intensive Care P O. Box 1350 5602 ZA Eindhoven The Netherlands Email Korsten@chello.nl Received 1 May 2002 and in revised form 2 October 2002 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. Keywords and phrases contrast agents local density random walk ultrasound videodensitometry. 1. INTRODUCTION The measurement of cardiac blood flow referred to as cardiac output CO is a .