doi: 10.1161/01.STR.0000022811.46115.70
(Stroke. 2002;33:1969.)
© 2002 American Heart Association, Inc.
Original Contributions |
Automatic Online Embolus Detection and Artifact Rejection With the First Multifrequency Transcranial Doppler
From the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany, and the Department of Neurology (D.R.), The National Hospital, Oslo, Norway.
Correspondence to David Russell, Department of Neurology, The National Hospital, 0027 Oslo, Norway. E-mail david.russell{at}klinmed.uio.no
Background and Purpose— The goal of this study was to assess the first multifrequency transcranial Doppler system specially developed for online automatic detection of cerebral microemboli.
Methods— The multifrequency Doppler instrumentation insonates simultaneously with 2.0- and 2.5-MHz frequencies. The detection threshold for embolus detection used in this study was a relative Doppler energy increase of >20 dB · ms, at which point the Doppler power increase was at least 5 dB and lasted >4 ms above the background energy. Four parameters were used in an optimized binary decision tree to recognize emboli: quarter Doppler shift, maximum duration limit, reference gate, and bidirectional enhancement. In in vitro studies, 200 plastic microspheres (80 µm), 200 gas bubbles (8 to 25 µm), and 600 artifacts were studied in a pulsatile closed-loop system. In vivo studies were carried out for 1 hour in 15 patients with mechanical heart valves and in 45 patients with carotid stenosis. This gave a total of 60 hours of online automatic monitoring in patients.
Results— All 400 plastic spheres and microbubbles were automatically detected and correctly classified. Of the 600 artifacts, 596 (99.3%) were correctly classified as artifacts, and 4 (0.7%) were incorrectly identified as emboli (
=0.992, P<0.001). The experienced observer detected a total of 554 emboli and 800 artifacts in the heart valve (521 emboli, 400 artifacts) and carotid stenosis (33 emboli, 400 artifacts) patients. With multifrequency Doppler, 546 of these emboli (98.6%) and 791 of these artifacts (98.9%) were automatically detected and correctly classified as embolus or artifact (=0.953, P<0.0001).
Conclusions— We found that multifrequency transcranial Doppler had a relatively high sensitivity and specificity when used to automatically detect cerebral microemboli and reject artifacts online.
Key Words: carotid stenosis • cerebral embolism • mechanical heart valve protheses • ultrasonography, Doppler
This article has been cited by other articles:
 |
|
 |
|
  F. Al-Rashidi, S. Blomquist, P. Hoglund, C. Meurling, A. Roijer, and B. Koul A new de-airing technique that reduces systemic microemboli during open surgery: A prospective controlled study J. Thorac. Cardiovasc. Surg., July 1, 2009; 138(1): 157 - 162. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Y. Tang, S. P.S. Howarth, S. R. Miller, M. J. Graves, A. J. Patterson, J.-M. U-King-Im, Z. Y. Li, S. R. Walsh, A. P. Brown, P. J. Kirkpatrick, et al. The ATHEROMA (Atorvastatin Therapy: Effects on Reduction of Macrophage Activity) Study: Evaluation Using Ultrasmall Superparamagnetic Iron Oxide-Enhanced Magnetic Resonance Imaging in Carotid Disease J. Am. Coll. Cardiol., June 2, 2009; 53(22): 2039 - 2050. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Skjelland, K. Krohg-Sorensen, B. Tennoe, S. J. Bakke, R. Brucher, and D. Russell Cerebral Microemboli and Brain Injury During Carotid Artery Endarterectomy and Stenting Stroke, January 1, 2009; 40(1): 230 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Nowell and M. Jahangiri Solid and gaseous cerebral microembolization after biologic and mechanical aortic valve replacement: Investigation with multirange and multifrequency transcranial Doppler ultrasound. J. Thorac. Cardiovasc. Surg., November 1, 2008; 136(5): 1391 - 1392. [Full Text] [PDF]
|
|
|
|
 |
|
 M. Barak, M. Kabha, D. Norman, M. Soudry, Y. Kats, and S. Milo Cerebral Microemboli During Hip Fracture Fixation: A Prospective Study Anesth. Analg., July 1, 2008; 107(1): 221 - 225. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Skjelland, A. Michelsen, F. Brosstad, J. L. Svennevig, R. Brucher, and D. Russell Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves Stroke, April 1, 2008; 39(4): 1159 - 1164. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Guerrieri Wolf, B. P. Choudhary, Y. Abu-Omar, and D. P. Taggart Solid and gaseous cerebral microembolization after biologic and mechanical aortic valve replacement: Investigation with multirange and multifrequency transcranial Doppler ultrasound J. Thorac. Cardiovasc. Surg., March 1, 2008; 135(3): 512 - 520. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. G. Wolf, Y. Abu-Omar, B. P. Choudhary, D. Pigott, and D. P. Taggart Gaseous and solid cerebral microembolization during proximal aortic anastomoses in off-pump coronary surgery: The effect of an aortic side-biting clamp and two clampless devices J. Thorac. Cardiovasc. Surg., February 1, 2007; 133(2): 485 - 493. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Abu-Omar, S. Cader, L. G. Wolf, D. Pigott, P. M. Matthews, and D. P. Taggart Short-term changes in cerebral activity in on-pump and off-pump cardiac surgery defined by functional magnetic resonance imaging and their relationship to microembolization. J. Thorac. Cardiovasc. Surg., November 1, 2006; 132(5): 1119 - 1125. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Maselli, R. Pizio, G. Borelli, and F. Musumeci Endovascular balloon versus transthoracic aortic clamping for minimally invasive mitral valve surgery: impact on cerebral microemboli Interactive CardioVascular and Thoracic Surgery, April 1, 2006; 5(2): 183 - 186. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Liebold, A. Khosravi, B. Westphal, C. Skrabal, Y.H. Choi, C. Stamm, A. Kaminski, A. Alms, T. Birken, D. Zurakowski, et al. Effect of closed minimized cardiopulmonary bypass on cerebral tissue oxygenation and microembolization J. Thorac. Cardiovasc. Surg., February 1, 2006; 131(2): 268 - 276. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Maselli, R. Pizio, and F. Musumeci Multifrequency transcranial Doppler for intraoperative automatic detection and characterisation of cerebral microemboli during port-access mitral valve surgery Interactive CardioVascular and Thoracic Surgery, February 1, 2006; 5(1): 32 - 35. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Russell, R. Brucher, H. S. Markus, and M. Punter Embolus Detection and Differentiation Using Multifrequency Transcranial Doppler * Response: Stroke, February 1, 2006; 37(2): 340 - 342. [Full Text] [PDF]
|
|
|
|
 |
|
 M. Rosenkranz, J. Fiehler, W. Niesen, C. Waiblinger, B. Eckert, O. Wittkugel, T. Kucinski, J. Rother, H. Zeumer, C. Weiller, et al. The Amount of Solid Cerebral Microemboli during Carotid Stenting Does Not Relate to the Frequency of Silent Ischemic Lesions AJNR Am. J. Neuroradiol., January 1, 2006; 27(1): 157 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Skjelland, J. Bergsland, R. Lundblad, P. S. Lingaas, K. A. Rein, S. Halvorsen, J. L. Svennevig, E. Fosse, R. Brucher, and D. Russell Cerebral microembolization during off-pump coronary artery bypass surgery with the Symmetry aortic connector device J. Thorac. Cardiovasc. Surg., December 1, 2005; 130(6): 1581 - 1585. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. S. Markus and M. Punter Can Transcranial Doppler Discriminate Between Solid and Gaseous Microemboli?: Assessment of a Dual-Frequency Transducer System Stroke, August 1, 2005; 36(8): 1731 - 1734. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Lund, R. B. Nes, T. P. Ugelstad, P. Due-Tonnessen, R. Andersen, P. K. Hol, R. Brucher, and D. Russell Cerebral emboli during left heart catheterization may cause acute brain injury Eur. Heart J., July 1, 2005; 26(13): 1269 - 1275. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Altaf, D. P. Auer, J. Gladman, S. T. MacSweeney, O. Wolf, P. Heider, M. Heinz, M. Hanke, H.H. Eckstein, H. Poppert, et al. Microembolization During Carotid Endarterectomy and Diffusion Weighted Imaging * Response: Stroke, June 1, 2005; 36(6): 1110 - 1112. [Full Text] [PDF]
|
|
|
|
|
|
R. Motallebzadeh and M. Jahangiri Distinguishing solid from gaseous emboli during cardiac surgery J. Thorac. Cardiovasc. Surg., May 1, 2005; 129(5): 1194 - 1194. [Full Text] [PDF]
|
|
|
|
|
|
D. Russell and R. Brucher Embolus Detection and Differentiation Using Multifrequency Transcranial Doppler Stroke, April 1, 2005; 36(4): 706 - 706. [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Abu-Omar, A. Cifelli, P. M. Matthews, and D. P. Taggart The role of microembolisation in cerebral injury as defined by functional magnetic resonance imaging Eur. J. Cardiothorac. Surg., September 1, 2004; 26(3): 586 - 591. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. D. Doblar Intraoperative Transcranial Ultrasonic Monitoring for Cardiac and Vascular Surgery Seminars in Cardiothoracic and Vascular Anesthesia, June 1, 2004; 8(2): 127 - 145. [Abstract] [PDF]
|
|
|
|
|
|
Y. Abu-Omar, L. Balacumaraswami, D. W. Pigott, P. M. Matthews, and D. P. Taggart Solid and gaseous cerebral microembolization during off-pump, on-pump, and open cardiac surgery procedures J. Thorac. Cardiovasc. Surg., June 1, 2004; 127(6): 1759 - 1765. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Saqqur, N. Dean, M. Schebel, M. D. Hill, A. Salam, A. Shuaib, and A. M. Demchuk Improved Detection of Microbubble Signals Using Power M-Mode Doppler Stroke, January 1, 2004; 35 (1): e14 - e17. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Lund, P. K. Hol, R. Lundblad, E. Fosse, K. Sundet, B. Tennoe, R. Brucher, and D. Russell Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery Ann. Thorac. Surg., September 1, 2003; 76(3): 765 - 770. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Russell and R. Brucher Online Automatic Discrimination Between Solid and Gaseous Cerebral Microemboli With the First Multifrequency Transcranial Doppler Stroke, August 1, 2002; 33(8): 1975 - 1980. [Abstract] [Full Text] [PDF]
|
|