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Geryes M, Ménigot S, Charara J, Nasserdine M, Mcheick A, Girault JM. Enhanced weak Doppler micro-embolic signal detection using energy fluctuations. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2018.08.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Detection of Doppler Microembolic Signals Using High Order Statistics. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:3243290. [PMID: 28096889 PMCID: PMC5206863 DOI: 10.1155/2016/3243290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/17/2016] [Indexed: 11/18/2022]
Abstract
Robust detection of the smallest circulating cerebral microemboli is an efficient way of preventing strokes, which is second cause of mortality worldwide. Transcranial Doppler ultrasound is widely considered the most convenient system for the detection of microemboli. The most common standard detection is achieved through the Doppler energy signal and depends on an empirically set constant threshold. On the other hand, in the past few years, higher order statistics have been an extensive field of research as they represent descriptive statistics that can be used to detect signal outliers. In this study, we propose new types of microembolic detectors based on the windowed calculation of the third moment skewness and fourth moment kurtosis of the energy signal. During energy embolus-free periods the distribution of the energy is not altered and the skewness and kurtosis signals do not exhibit any peak values. In the presence of emboli, the energy distribution is distorted and the skewness and kurtosis signals exhibit peaks, corresponding to the latter emboli. Applied on real signals, the detection of microemboli through the skewness and kurtosis signals outperformed the detection through standard methods. The sensitivities and specificities reached 78% and 91% and 80% and 90% for the skewness and kurtosis detectors, respectively.
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Goldberg I, Auriel E, Russell D, Korczyn AD. Microembolism, silent brain infarcts and dementia. J Neurol Sci 2012; 322:250-3. [PMID: 22429666 DOI: 10.1016/j.jns.2012.02.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 02/22/2012] [Indexed: 10/28/2022]
Abstract
Cognitive decline becomes more prevalent than ever in parallel with the increasing life expectancy of the population. Alzheimer' disease (AD) and cerebral vascular lesions are common in the elderly and represent, with increased age, the most frequent contributors to cognitive decline. It is now believed that these pathologies frequently coexist in the same brain. The border discriminating vascular dementia from AD is blurred and challenges our understanding of these clinical entities. Further research, at both basic and clinical levels, is mandatory in order to better understand the interactions of vascular ischemic injury and primary degenerative physiopathologies of the brain, in order to prevent and better manage patients with cognitive decline. We review recent published clinical evidence of silent brain ischemia as a contributor to cognitive decline and dementia. Microemboli, from both cardiac and vascular origins, have been shown to be associated with structural changes in the brain. The role of transcranial Doppler as an objective tool for detecting and quantifying microemboli is discussed in light of recent clinical evidence.
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Affiliation(s)
- I Goldberg
- Department of Neurology, Hadassah Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel.
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Lipperts MGA, Sauren LDC, Maessen JG, Hoeks APG, Mess WH. Quantification of embolic showers using radio-frequency based TCD analysis. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:395-402. [PMID: 19084324 DOI: 10.1016/j.ultrasmedbio.2008.09.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 07/21/2008] [Accepted: 09/17/2008] [Indexed: 05/27/2023]
Abstract
During cardiac surgery and cardiology interventions, microemboli may be generated and disperse in the systemic circulation. The amount of microemboli that ends up in cerebral blood vessels is associated with postoperative neurologic complications. During cardiac surgery a large amount of cerebral microemboli can occur at once and create so-called "cerebral embolic showers." To correlate postoperative neurologic outcome to cerebral embolic load, a quantitative evaluation of these embolic showers is necessary. The standard monitoring technology to visualize cerebral microemboli is transcranial Doppler (TCD). Although the conventional TCD systems are equipped with software claiming to detect microembolic signals, none of the existing TCD systems is capable of an accurate estimation of the number of cerebral microemboli in embolic showers. In this study, an algorithm with a high temporal resolution, based on the radiofrequency (RF) signal of a TCD system, has been designed to quantify these showers. Evaluation by three independent observers of a training set demonstrates that the proposed method has a sensitivity of at least one order of magnitude better than the automatic detection algorithm on the existing Doppler device used. RF-based emboli detection can possibly become a standard addition to conventional Doppler methods, considering that accurate estimation of the embolic load supports quantification of neurologic risk during various surgical procedures.
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Affiliation(s)
- M G A Lipperts
- Department of Cardiothoracic Surgery, Cardiovascular Research Institute Maastricht, Academic Hospital Maastricht, Maastricht, The Netherlands
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Skjelland M, Michelsen A, Brosstad F, Svennevig JL, Brucher R, Russell D. Solid Cerebral Microemboli and Cerebrovascular Symptoms in Patients With Prosthetic Heart Valves. Stroke 2008; 39:1159-64. [DOI: 10.1161/strokeaha.107.493031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Mona Skjelland
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Annika Michelsen
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Frank Brosstad
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Jan L. Svennevig
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - Rainer Brucher
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
| | - David Russell
- From the Department of Neurology (M.S., D.R.), the Research Institute for Internal Medicine (A.M., F.B.), and the Department of Thoracic and Cardiac Surgery (J.L.S.), Rikshospitalet-Radiumhospitalet Medical Center, University of Oslo, Oslo, Norway, and the Department of Medical Engineering (R.B.), University of Applied Sciences, Ulm, Germany
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Keunen RWM, Hoogenboezem R, Wijnands R, Van den Hengel ACM, Ackerstaff RGA. Introduction of an embolus detection system based on analysis of the transcranial Doppler audio-signal. J Med Eng Technol 2008; 32:296-304. [DOI: 10.1080/03091900701541265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Chung EML, Fan L, Naylor AR, Evans DH. Characteristics of Doppler embolic signals observed following carotid endarterectomy. ULTRASOUND IN MEDICINE & BIOLOGY 2006; 32:1011-23. [PMID: 16829315 DOI: 10.1016/j.ultrasmedbio.2006.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Revised: 02/20/2006] [Accepted: 03/01/2006] [Indexed: 05/10/2023]
Abstract
Postoperative Doppler embolic signals following carotid endarterectomy (CEA) are associated with an increased risk of stroke, but the characteristics of these signals are rarely reported. In this study, we survey signals from 1485 emboli, assumed to consist predominantly of thrombus. Data were obtained by monitoring the middle cerebral arteries of 100 consecutive CEA patients during postoperative recovery. The distribution of embolic signal frequencies, intensities and durations revealed that embolic signals do not occur randomly in the sonogram. In particular, we find that the signals possess a characteristic distribution of velocities reflecting the preferred path of the embolus through the artery (at approximately 75% of the distance between the centre of the artery and the artery wall). Embolic signals were more likely to be observed at cardiac cycle positions between 35% and 80% from the start of systole than elsewhere. After eliminating other considerations, we hypothesized that this peak in the distribution of signals in the sonogram arose due to the localization of emboli trajectories and a strong tendency for emboli to detach from the carotid bifurcation during systole.
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Affiliation(s)
- Emma M L Chung
- Department of Medical Physics, University Hospitals of Leicester, Leicester, UK
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