Impact of Clinical Environment on Embolus Detection: A Comparison of Automated and Manual Detection of Doppler Embolic SignalsChung E.M.L.a · Fan L.a · Naylor A.R.b · Evans D.H.a, b
aDepartment of Medical Physics, University Hospitals of Leicester, and bDepartment of Cardiovascular Sciences, Faculty of Medicine and Biological Science, University of Leicester, Leicester, UK
Do you have an account?
- Rent for 48h to view
- Buy Cloud Access for unlimited viewing via different devices
- Synchronizing in the ReadCube Cloud
- Printing and saving restrictions apply
Rental: USD 8.50
Cloud: USD 20.00
Article / Publication Details
Background: Transcranial Doppler ultrasound detection of weak embolic signals is inhibited by intrinsic limitations within the human auditory system. Psychoacoustics effects are likely to be exacerbated in a clinical environment, where automated embolus detection has potential to surpass manual detection. In this study we quantify the impact of clinical environment on manual detection of Doppler embolic signals following carotid surgery. We also discuss the implications of psychoacoustics considerations for the evaluation of automated detection systems. Method: Concurrent monitoring by vascular technologists and an automated embolus detection system were performed for 50 consecutive patients during postoperative recovery. Both detection methods were evaluated against a majority decision human expert panel analyzing under ideal conditions. Results: Clinical environment reduced the overall sensitivity of manual monitoring by ∼23%, mainly due to a ∼2-dB increase in the lower threshold for detection. Clinical environment was also associated with a reduction in positive predictive value for manual detection of ∼9% compared to ideal conditions. Automated monitoring, which is not affected by environment, was marginally more sensitive for detection of weaker embolic signals. Conclusions: One in 4 weak embolic signals was missed during routine clinical monitoring compared to ideal conditions. Automated detection (in this study) performed slightly better than human observers but did not approach the performance of the majority decision panel.
© 2007 S. Karger AG, Basel
- Chung E, Fan L, Degg C, Evans DH: Detection of Doppler embolic signals: psychoacoustic considerations. Ultrasound Med Biol 2005;31:1177–1184.
- Markus HS, Ackerstaff R, Babikian V, et al: Intercenter agreement in reading Doppler embolic signals: a multicenter international study. Stroke 1997;28:1307–1310.
- Dittrich, R, Ritter MA, Kaps M, et al: The use of embolic signal detection in multicenter trials to evaluate antiplatelet efficacy: signal analysis and quality control mechanisms in the CARESS trial. Stroke 2006;37:1065–1069.
- Van Zuilen EV, Mess WH, Jansen C, et al: Automatic embolus detection compared to human experts: a Doppler ultrasound study. Stroke 1996;26:210–213.
- Fan L, Evans DH, Naylor AR: Automated embolus identification using a rule-based expert system. Ultrasound Med Biol 2001;27:1065–1077.
- Brucher R, Russell D: Automatic online embolus detection and artifact rejection with the first multifrequency transcranial Doppler. Stroke 2002;33:1969–1974.
- Cullinane M, Kaposzta Z, Reihill S, Markus H: Online automated detection of cerebral embolic signals from a variety of embolic sources. Ultrasound Med Biol 2002;28:1271–1277.
- Fan L, Evans DH, Naylor AR, et al: Real-time identification and archiving of micro-embolic Doppler signals using a knowledge-based DSP system. Med Biol Eng Comput 2004;42:193–200.
- Devuyst G, Darbellay GA, Vesin JM, et al: Automated classification of HITS into artefacts or solid or gaseous emboli by a wavelet representation combined with dual-gate TCD. Stroke 2001;32:2803–2809.
- Darbellay GA, Duff R, Vesin JM, et al: Solid or gaseous circulating brain emboli: are they separable by transcranial ultrsound? J Cereb Blood Flow Metab 2004;24:860–868.
- Georgiadis D, Wenzel A, Zerkowski HR, et al: Automated intraoperative detection of Doppler microembolic signals using the bigate approach. Stroke 1998;28:137–139.
- Keunen RWM, Stam CJ, Tavy DLJ, et al: Preliminary report of detecting microembolic signals in transcranial Doppler time series with nonlinear forecasting. Stroke 1998;29:1638–1543.
- Consensus Committee of the Ninth International Cerebral Hemodynamic Symposium: Basic identification criteria of Doppler microembolic signals. Stroke 1995;26:1123.
- Chung E, Fan L, Naylor AR, Evans DH: Characteristics of Doppler embolic signals observed following carotid endarterectomy. Ultrasound Med Biol 2006;32:1011–1023.
Moore BCJ: An Introduction to the Psychology of Hearing, ed 4. London, Academic Press, 1997.
- Lennard N, Smith JL, Hayes P, et al: Transcranial Doppler directed dextran therapy in the prevention of carotid thrombosis: three hour monitoring is as effective as six hours. Eur J Vasc Endovasc Surg 1999;17:301–305.
Article / Publication Details
Copyright / Drug Dosage / DisclaimerCopyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.