Automatic classification of HITS into artifacts or solid or gaseous emboli by a wavelet representation combined with dual-gate TCD.
Background and Purpose: Transcranial Doppler (TCD) can detect high-intensity transient signals (HITS) in the cerebral circulation. HITS may correspond to artifacts or solid or gaseous emboli. The aim of this study was to develop an offline automated Doppler system allowing the classification of HITS...
| Publicado en: | Stroke (00392499) Vol. 32; no. 12; pp. 2803 - 2810 |
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| Autores principales: | , , , , , , , , , , , , , , , , , , , |
| Formato: | research tables/charts tracings Journal Article |
| Publicado: |
Lippincott Williams & Wilkins
2001 Dec
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=106931473&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 106931473 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 00392499 1FT jtl: Stroke (00392499) issn: 00392499 maglogo: N pubinfo: dt: 2001 Dec vid: 32 iid: 12 pid: 433 pub: Lippincott Williams & Wilkins place: Baltimore, Maryland artinfo: ui: 106931473 106931473 NLM11739977 2002063225 10.1161/hs1201.099714 NLM11739977 106931473 ppf: 2803 ppct: 7 formats: tig: atl: Automatic classification of HITS into artifacts or solid or gaseous emboli by a wavelet representation combined with dual-gate TCD. aug: au: Devuyst G Darbellay GA Vesin J Kemény V Ritter M Droste DW Molina C Serena J Sztajzel R Ruchat P Lucchesi C Dietler G Ringelstein EB Despland P Bogousslavsky J Devuyst, G Darbellay, G A Vesin, J M Kemény, V Ritter, M affil: Department of Neurology, CHUV, the Signal Processing Laboratory, Swiss Federal Institute of Technology, Lausanne, Geneva, Switzerland sug: subj: Ultrasonography, Doppler, Transcranial Methods Intracranial Embolism and Thrombosis Diagnosis Intracranial Embolism and Thrombosis Classification Algorithms Signal Processing, Computer Assisted Sensitivity and Specificity Cerebral Arteries Ultrasonography Artifacts Reproducibility of Results Predictive Value of Tests kappa Statistic Human ab: Background and Purpose: Transcranial Doppler (TCD) can detect high-intensity transient signals (HITS) in the cerebral circulation. HITS may correspond to artifacts or solid or gaseous emboli. The aim of this study was to develop an offline automated Doppler system allowing the classification of HITS.Methods: We studied 600 HITS in vivo, including 200 artifacts from normal subjects, 200 solid emboli from patients with symptomatic internal carotid artery stenosis, and 200 gaseous emboli in stroke patients with patent foramen ovale. The study was 2-fold, each part involving 300 HITS (100 of each type). The first 300 HITS (learning set) were used to construct an automated classification algorithm. The remaining 300 HITS (validation set) were used to check the validity of this algorithm. To classify HITS, we combined dual-gate TCD with a wavelet representation and compared it with the current "gold standard," the human experts.Results: A combination of the peak frequency of HITS and the time delay makes it possible to separate artifacts from emboli. On the validation set, we achieved a sensitivity of 97%, a specificity of 98%, a positive predictive value (PPV) of 99%, and a negative predictive value (NPV) of 94%. To distinguish between solid and gaseous emboli, where positive refers now to the solid emboli, we used the peak frequency, the relative power, and the envelope symmetry of HITS. On the validation set, we achieved a sensitivity of 89%, a specificity of 86%, a conditional PPV of 89%, and a conditional NPV of 89%.Conclusions: An automated wavelet representation combined with dual-gate TCD can reliably reject artifacts from emboli. From a clinical standpoint, however, this approach has only a fair accuracy in differentiating between solid and gaseous emboli. pubtype: Academic Journal doctype: research tables/charts tracings Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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