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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Diagnosis, microemboli detection and hemodynamic monitoring of intracranial atherosclerosis by transcranial Doppler in the ischemic stroke. / CUHK electronic theses & dissertations collection

January 2008 (has links)
Early deterioration and long-term recurrence were common after stroke or transient ischemic attach (TIA), however, it is unclear whether they were correlated with active embolization and the consequent new cerebral infarct in acute phase. By employing TCD and diffusion weighted imaging (DWI), we studied the significance of the progression of MES and infarcts during acute phase on the clinical outcomes. We found that the disappearance of MES was correlated with better improvement on day 7 of recruitment; for the long-term outcome, occurrence of exacerbating infarct tended to predict recurrent stroke. Treatment aiming to reduce MES and prevent infarct exacerbation in acute phase may improve the prognosis after stroke. / Finally, one study was performed to assess the changes of hemodynamic parameters after stenting of severe stenosis in the MCA. We aimed to investigate whether TCD can reflect the lumen changes after revascularization and detect hyperperfusion. The findings showed that the velocity of stented MCA in most patients normalized within 24 hours after procedure, but the role of TCD in detecting restenosis in long run needed to be verified; no one suffered from hyperperfusion during the period of our study. The long-term outcomes of patients with normalized velocity versus those with persistently high velocity needed to be further studied. Apart from the velocity changes, changes of the collateral flow after intervention may also be an important part of hemodynamic changes. (Abstract shortened by UMI.) / It was suggested that anti-platelet therapy can reduce the MES, but little was known about the efficacy of low molecular weight heparin (LMWH) although in theory LMWH can reduce the red fibrin-dependent thromboemboli. As a sub-analysis of Fraxiparine in Ischemic Stroke (FISS)-tris study, our study did not show advantages of LMWH in eliminating MES compared with aspirin. / Previous studies showed the accuracy of TCD in diagnosis of middle cerebral artery (MCA) stenosis was variable and the positive predictive value (PPV) was less than 50% in a recent report. One of the important reasons was that most criteria were based on the velocity-only method, ignoring other non-velocity information. Thus, we tried to establish new diagnostic criteria by means of designing an assessment form which integrated more characteristics apart from the velocity acceleration. A composite score for each MCA was calculated according to following parameters in the form: Velocity Scale (score 0-6 for peak systolic velocities<140 to ≥300cm/s), Hemodynamic Scale (score 0-5 for focal or diffuse velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), Spectrum Scale (score 0-2 for normal spectrum, turbulence and musical murmurs). Our results showed that compared with the previously reported criteria, the score calculated from the assessment form yielded much more balanced accuracy against magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). However, the composition of the assessment form was only based on personal experience and need to be further modified. Multicenter studies with large sample size are also needed to confirm the advantages of this new method. / Second, we performed three studies to investigate the relationship between the progression of MES and the short or long-term outcome and the relationship between MES and different treatments. / Hao, Qing. / Adviser: Ka Sing Wong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3419. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 155-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
32

Neuronavigation-Guided Transcranial Ultrasound: Development towards a Clinical System and Protocol for Blood-Brain Barrier Opening

Wu, Shih-Ying January 2016 (has links)
Brain diseases including neurological disorders and tumors remain undertreated due to the challenge in accessing the brain, and blood-brain barrier (BBB) restricting drug delivery, which also profoundly limits the development of pharmacological treatment. Focused ultrasound (FUS) with acoustic agents including microbubbles and nanodroplets remains as the only method to open the BBB noninvasively, locally, and transiently to assist drug delivery. For an ideal medical system to serve a broad patient population, it requires precise and flexible targeting with simulation to personalize treatment, real-time monitoring to ensure safety and effectiveness, and rapid application, as repetitive pharmacological treatment is often required. Since none of current systems fulfills all the requirements, here we designed a neuronavigation-guided FUS system with protocol assessed in in vivo mice, in vivo non-human primates, and human skulls from in silico preplanning, online FUS treatment and real-time acoustic monitoring and mapping, to post-treatment assessment using MRI. Both sedate and awake non-human primates were evaluated with total treatment time averaging 30 min and 3-mm targeting accuracy in cerebral cortex and subcortical structures. The FUS system developed would enable transcranial FUS in patients with high accuracy and independent of MRI guidance.
33

The Detection of Cognitive Activity within a System-paced Dual-state Selection Paradigm Using a Combination of fNIRS and fTCD Measurements

Faress, Ahmed 22 November 2012 (has links)
Functional neuroimaging techniques such as near-infrared spectroscopy (NIRS) have been studied in brain-computer interface (BCI) development. Previous research has suggested that the addition of a second brain-monitoring modality may improve the accuracy of a NIRS-BCI. The objective of this study was to determine whether the classification accuracies achievable by a multimodal BCI, which combines NIRS and transcranial Doppler ultrasonography (TCD) signals, can exceed those attainable using a unimodal NIRS-BCI or TCD-BCI. Nine able-bodied subjects participated in the study. Simultaneous measurements were made with NIRS and TCD instruments while participants were prompted to perform a verbal fluency task or to remain at rest, within the context of a block-stimulus paradigm. In five of nine (55.6%) participants, classification accuracies with the NIRS-TCD system were significantly higher (p<0.05) than with NIRS or TCD systems alone. Our results suggest that multimodal neuroimaging may be a promising approach towards improving the accuracy of future BCIs.
34

The Detection of Cognitive Activity within a System-paced Dual-state Selection Paradigm Using a Combination of fNIRS and fTCD Measurements

Faress, Ahmed 22 November 2012 (has links)
Functional neuroimaging techniques such as near-infrared spectroscopy (NIRS) have been studied in brain-computer interface (BCI) development. Previous research has suggested that the addition of a second brain-monitoring modality may improve the accuracy of a NIRS-BCI. The objective of this study was to determine whether the classification accuracies achievable by a multimodal BCI, which combines NIRS and transcranial Doppler ultrasonography (TCD) signals, can exceed those attainable using a unimodal NIRS-BCI or TCD-BCI. Nine able-bodied subjects participated in the study. Simultaneous measurements were made with NIRS and TCD instruments while participants were prompted to perform a verbal fluency task or to remain at rest, within the context of a block-stimulus paradigm. In five of nine (55.6%) participants, classification accuracies with the NIRS-TCD system were significantly higher (p<0.05) than with NIRS or TCD systems alone. Our results suggest that multimodal neuroimaging may be a promising approach towards improving the accuracy of future BCIs.
35

Galvos ir kaklo kraujagyslių ultragarsinių tyrimų parametrų vertė prognozuojant lengvo kognityvinio sutrikimo progresavimą į demenciją / The value of head and neck vascular ultrasound parameters to predict the conversion from mild cognitive impairment to dementia

Rutkauskas, Saulius 18 June 2014 (has links)
Demencija yra vienas iš dažniausiai sutinkamų psichikos sutrikimų vyresniame amžiuje. Pastebėta, kad dalis vyresnio amžiaus pacientų, kuriems vėliau išsivysto demencija, dažniau nei bendraamžiai skundžiasi pažinimo sutrikimais, tačiau kasdieninė veikla yra nesutrikusi. Ši būklė buvo pavadinta lengvu kognityviniu sutrikimu (LKS). Neurosonografiniai tyrimai pateikia daug naudingos informacijos apie funkcinius galvos ir kaklo kraujagyslių parametrus. Tyrimo tikslas buvo nustatyti neurosonografinių galvos ir kaklo arterijų parametrų vertę prognozuojant demenciją lengvu kognityviniu sutrikimu sergantiems pacientams. Tyrimo uždaviniai: 1) ištirti LKS turinčių pacientų demografines ir klinikines charakteristikas ir įvertinti jų ir progresavimo į demenciją ryšį; 2) ištirti LKS turinčių pacientų ekstrakranijinės kraujotakos parametrus ir įvertinti jų ir progresavimo į demenciją ryšį; 3) ištirti LKS turinčių pacientų intrakranijinės kraujotakos parametrus ir įvertinti jų ir pogresavimo į demenciją ryšį; 4) ištirti LKS turinčių pacientų miego arterijų sienelių parametrus ir įvertinti jų ir pogresavimo į demenciją ryšį; 5) ištirti LKS turinčių pacientų miego arterijų aterosklerozinius požymius ir įvertinti jų ir pogresavimo į demenciją ryšį; 6) įvertinti bendrą tiriamųjų demografinių ir klinikinių charakteristikų bei neurosonografinių parametrų diagnostinę reikšmę prognozuojant progresavimą iš lengvo kognityvinio sutrikimo į demenciją. / Dementia is one of the most commonly occurring mental disorders in older age. It was noticed that some of the elderly patients who later develop dementia, more often than contemporaries complained of cognitive impairment, but daily activities were not affected. This condition was called mild cognitive impairment (MCI). Neurosonographic studies provide a lot of useful information about the functional head and neck vascular parameters. The aim of our study was to provide more information about the significance of the extra- and intracranial arterial blood flow and carotid arterial wall parameters for prediction of dementia for patients with MCI. Objectives of the study is 1) to investigate the demographic and clinical characteristics of MCI patients and to assess their relation with progression to dementia; 2) to investigate blood flow parameters of the extracranial arteries and to assess their relation with progression to dementia; 3) to investigate blood flow parameters of the intracranial arteries and to assess their relation with progression to dementia; 4) to investigate the intima-media thickness and stiffness of carotid arteries walls and to assess their relation with progression to dementia, 5) to investigate the atherosclerotic changes and to assess their relation with progression to dementia; 6) to assess the value of demographic and clinical characteristics and neurosonographic parameters for prediction of dementia.
36

Qualidade da janela transtemporal definida pelo ultrassom transcraniano colorido / Quality Assessment for the Transtemporal Window by Transcranial Color-Coded Sonography

Renata da Silva Almeida Santos 17 October 2016 (has links)
INTRODUÇÃO: O ultrassom transcraniano colorido (UTC) é um eficiente método para avaliação da circulação intracraniana e do fluxo sanguíneo cerebral em diversas condições clínicas incluindo o acidente vascular isquêmico agudo. Uma das principais limitação deste método reside na incapacidade de insonação intracraniana adequada através da janela transtemporal em até 20% dos pacientes. Neste contexto, surge a necessidade do desenvolvimento de uma metodologia estruturada que permitisse caracterizar a qualidade da janela transtemporal de forma mais detalhada e objetiva. No presente estudo, objetivamos: determinar a frequência de visualização dos principais marcos anatômicos pela insonação com UCT utilizando-se a janela transtemporal em pacientes com AVCI agudo; classificar o grau de dificuldade na visualização da primeira porção da artéria cerebral média (ACM) ipsilateral ao lado insonado; determinar a influência da idade, sexo, etnia no na qualidade da janela transtemporal pelo UTC. METODOLOGIA: Avaliamos prospectivamente todos os pacientes adultos, consecutivos, com o primeiro e único episódio de acidente vascular isquêmico no período de julho de 2014 a janeiro de 2015 com um exame de UTC (modo B e Doppler colorido). Dois examinadores classificaram a qualidade da janela transtemporal pelo modo B utilizando uma escore baseado na qualidade da visualização de referencias anatômicas (osso temporal contralateral, asa menor do esfenoide ipsilateral e mesencéfalo) variando de 0 (janela ausente) a 9 (excelente janela). Os preditores independentes de uma boa visualização do sinal da ACM ao UTC foram identificados através de um modelo de regressão logística multivariada selecionado pelo método backward. A acurácia do escore do modo B foi avaliada através dos parâmetro de sensibilidade, especificidade e estatística C (curva ROC). RESULTADOS: entre os 200 paciente incluídos no estudo (55% do sexo masculino e com idade média de 61,17 ± 15,22 anos) o osso temporal contralateral não foi visualizado em 48,5% dos casos, o mesencéfalo foi visualizado em 65% e a asa menor do esfenoide foi visualizada em 66%. A porção proximal da artéria cerebral media (M1) foi visualizada em 62% dos casos. Na análise multivariada, a idade (OR: 0,95; IC95%:0,92 - 0,99; p=0,011) e a pontuação no escore do modo B (OR: 2,97; IC95%:1,93- 4,55; p<0,001) foram preditores independentes de visualização do sinal da ACM ao UTC. A pontuação no escore do modo B mostrou um preditor acudado para subsequente visualização da artéria cerebral médica pelo Doppler colorido com uma área sob a curva ROC de 0,896 (p<0,001). O escore de 2 apresentou uma sensibilidade e especificidade de 80 e 87% para este fim, respectivamente. CONCLUSÃO: O escore do modo B baseado na visualização de referência anatômicas intracranianas pelo modo B do UTC é uma ferramenta útil com boa acurácia para capacidade de visualização do fluxo da artéria cerebral media ipsilateral ao UTC. Este escore permite descrever de forma mais detalhada a qualidade de janela transtemporal ao UTC, em suas diferentes aplicações. / INTRODUCTION: Transcranial Color-Coded Sonography (TCCS) is an widely-used method to assess the intracranial circulation and cerebral blood flow in several clinical conditions including acute ischemic stroke. One of the main limitations of this technic is related to the quality of the transtemporal window, which is poor in about 20% of cases. In this context, it is important to develop an structured approach to better define the quality of the transtemporal window. In this study we aimed to evaluate how frequently the main anatomic landmarks can be adequately visualized by TCCS in acute stroke patients using the transtemporal window; to assess the proportion of patients in which the ipsilateral middle cerebral artery of visualized by TCCS; and to identify the main predictors of a poor transtemporal window on TCCS. METHODS: We examined 200 consecutive acute ischemic stroke (AIS) patients, from July 2014 to January 2015. All patients underwent prospective TCCS evaluation. Visualization of the contralateral temporal bone (CTB), midbrain (MB) and lesser sphenoid wing (LSW) was scored on B-mode images. The resulting B-Mode Score varied from 0 (poor visualization) to 9 (perfect window). A multivariate logistic regression model (backward selection) was used to identify the independent predictors of visualization of the MCA signal by TCCS. The relationship between these B-Mode Score and visualization of the proximal portion of the ipsilateral MCA was assessed in terms of sensitivity, specificity, ROC curve and C statistics. RESULTS: Among 200 AIS patients (male 55%; mean age, 61.17 ± 15,22 years), CTB was invisible\' in 48,5%, the MB was visualized in 65%; and the LSW was seen in 66%. The M1 segment of the MCA was detected in 62% of cases. After multivariate analysis, age (OR: 0.95; 95CI%:0.92-0.99; p=0.011) and B-Mode score (OR: 2.97;95CI%:1.93-4.55; p<0.001) were independente predictors of visualization of MCA signal by TCCS. The BMode Score show good accuracy for the prediction of MCA visualization with an AUC of 0,896. (p<0,001) on the respective ROC curve. A cut-off of 2 on the B-mode score showed a sensitivity of 80% and a specificity of 87% for adequate MCA visualization by TCCS. CONCLUSION: The B-mode Score, which is based on the visualization of intracranial anatomical landmarks on B-Mode, appears to be a reliable way to characterize the quality of the transtemporal window, with a good accuracy as predictor for visualization of the ipsilateral MCA on TCCS. This score may allow more detailed characterization of the transtemporal window for different clinical applications of TCCS.
37

Predicting Vigilance Performance Under Transcranial Direct Current Stimulation

Bridges, Nathaniel Reese 05 July 2011 (has links)
No description available.
38

Acurácia da ultrassonografia transcraniana colorida no diagnóstico de forame oval patente / Transcranal color coded sonography for detection of patent foramen ovale in young patients with stroke

Libardi, Milena Carvalho 26 January 2016 (has links)
Introdução:O Forame Oval Patente (FOP) é a comunicação direita-esquerda (CDE) ou shunt direita-esquerda (SDE) mais comum e frequentemente encontrada em adultos jovens com Acidente Vascular Cerebral (AVC) relacionado ao mecanismo de embolia paradoxal. A Ecocardiografia Transesofágia (ETE) é considerada o padrão para visualização direta do FOP. O Doppler Transcraniano com o teste de microbolhas é frequentemente usado para detectar CDE com boa correlação com o ETE para o diagnóstico de FOP. Mais recentemente, a Ultrassonografia Transcraniana Colorida (TCCS) com inclusão do modo-B e fluxo de cor tem superado o DTC (que é realizado \"as cegas\") em muitas aplicações clínicas mas a acurácia do TCCS para a detecção de CDE e FOP não tem sido sistematicamente avaliada. Objetivo: Determinar se o TCCS é uma ferramenta acurada para identificar tanto FOP quanto CDE. Métodos: Foram recrutados 106 pacientes prospectivamente com Acidente Vascular Cerebral Isquêmico menores de 55 anos admitidos na Unidade de Emergência do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto (HCFMRP). Os pacientes foram submetidos aos exames de ETE, DTC e TCCS e todos os exames incluíram a técnica do teste de microbolhas. Os examinadores foram cegos para os resultados desses exames e foi calculado a concordância Kappa de Cohen inter-examinadores para o TCCS e DTC. A acurácia para o TCCS foi calculada em comparação ao ETE. Resultados: Foram detectados CDE em 54 (50.9%) dos pacientes (idade média 43.9 ± 8.2 anos) com Kappa de Cohen de 0.92 (IC 95% 0.78-1.0) quando realizados TCCS e TCD. TEE e TCSS foram positivos em 23/98 (23.4%) e ETE negative em 20/98 (20.4%). Em 30 (28.3%) o ETE revelou FOP. O TCSS teve uma sensibilidade de 88.4%(IC 95% 0.68-0.97) e especificidade de 72.2%(IC 95% 0.60-0.81) e uma razão de verossimilhança positive de 3.18 (IC 95% 2.14-4.73) para o diagnóstico de FOP. Conclusão: TCCS e DTC tiveram excelente concordância. TCCS tem uma boa acurácia para a detecção de FOP e CDE em pacientes jovens com Acidente Vascular Isquêmico / Introduction: Patent Foramen Ovale (PFO) is the most common right-to-left shunt (RLS) and is often found in young patients with stroke related to paradoxical embolism. ContrastEnhanced Transesophageal Echocardiography (TEE) is considered a gold standard to visualize PFO. Transcranial Doppler (TCD) with bubble test is often used to detect RLS with good correlation to TEE for the diagnostic of PFO. More recently, Transcranial Color Coded Sonography (TCCS) which included B-mode and color coded imaging has overcome blind TCD in many clinical applications but the accuracy of TCCS for detection of RLS and PFO has not been systematically evaluated. Hypothesis: To determine if the TCCS is an accurate tool to identify both PFO and RLS. Methods: We investigate 106 patients with ischemic stroke under 55 years-old admitted from 2012 to 2014 in a tertiary academic hospital. Patients were evaluated with TEE, TCD and TCCS, and all exams included a saline bubble test. The examiners were blinded for the other tests results. Kappa agreement was calculated inter-examiners for TCCS and TCD. Accuracy of TCCS was calculated in comparison to TEE. Results: We detected a RLS in 54 (50.9%) patients (age mean 43.9 ± 8.2) with kappa agreement 0.92 (95%CI 0.78-1.0) when performed TCCS and TCD. TEE and TCSS were positive in 23/98 (23.4%) and TEE did not reveal contrast in 20/98 (20.4%). In 30 (28.3%) patients only TEE revealed a PFO. TCSS had a sensitivity of 88.4% (95%CI 0.68-0.97), specificity of 72.2% (95%CI 0.60-0.81) and positive likelihood ratio of 3.18 (2.14-4.73) of the diagnosis of PFO. Conclusion: TCCS and TCD had an excellent agreement. TCCS has a good accuracy for the detection of PFO and RLS in young patients with stroke
39

Visuell evozierte Flussgeschwindigkeitänderungen in der A. cerebri posterior bei Normalprobanden und Patienten mit Leitungsverzögerungen im Sehbahnbereich

Guhr, Susanne 24 July 2002 (has links)
In der vorliegenden Arbeit werden am Beispiel visuell evozierter Flussgeschwindigkeitsänderungen die Anpassung der zerebralen Hämodynamik an Änderungen der Gehirnaktivität untersucht. Dazu wurde das nichtinvasive Verfahren der transkraniellen Dopplersonographie angewendet. Ziele der Arbeit waren das Erstellen von Normwerten der Latenzen und Amplituden visuell evozierter Geschwindigkeitsänderungen an einer Gruppe von Normalprobanden sowie die Prüfung der Sensitivität der zeitlichen Auflösung dieses Verfahrens. Die Untersuchungen wurden an einer Gruppe von 20 Normalprobanden und an einer Gruppe von 16 Patienten, welche eine Leitungsverzögerung im vorderen Sehbahnbereich (nachgewiesen mit den Visuell Evozierten Potentialen anhand der P100) zeigten, vorgenommen. Die Lichtstimulation erfolgte mit einer LED-Blitzbrille und einer Stimulationszeit von jeweils 10 s "on" und "off" mit einer Frequenz von 15 Hz bei konstanter Lichtintensität. In der Kontrollgruppe ermittelten wir einen reaktiven Geschwindigkeitsanstieg von 16 %. Der Anstieg der Flussgeschwindigkeit erfolgte nach 1,4 s bzw. nach 1 s bei Flussantworten, die gleich mit einem Anstieg der Geschwindigkeit begannen. Das initiale Maximum wurde nach 5,6 s erreicht, 2,9 s nach Stimulationsende begann die Geschwindigkeit wieder abzufallen. Außer bei den Latenzwerten bis zum Anstieg ohne vorherigen Abfall der Flussgeschwindigkeit gab es keine signifikanten Unterschiede zwischen den beiden untersuchten Gruppen. Die von uns ermittelten Werte lagen in den Größenordnungen der Ergebnisse anderer Studien mit ähnlichem Versuchsaufbau. Auch die unterschiedlichen Verläufe der Flussantworten wurden bis auf das "initiale undershoot" auch von anderen Autoren beschrieben. Als Erklärung dafür diskutierten wir Aktivierungen anderer Hirnareale und eine Umverteilung des Blutflusses dorthin zu Beginn. Die zeitliche Auflösung der Dopplersonographie ist gut geeignet zeitliche Abläufe der zerebralen Hämodynamik zu untersuchen. Sie ist aber nicht sensitiv genug Leitungsverzögerungen im vorderen Sehbahnbereich zu erfassen. Die Möglichkeiten der Anwendung in der klinischen Routine liegen daher in der Untersuchung von Störungen der neurovaskulären Kopplung. / In this paper we present an investigation about the adaption of the cerebral hemodynamic to changing of the brain activation at the example of visual evoked blood flow response. Therefore we used the transcranial Doppler sonography as a noninvasive method. The aim of the work was to determine normal values of the latencies and amplitudes of visual evoked flow changing and to investigate the sensitivity of the temporal resolution of this method. We examined a group of 20 healthy volunteers and a group of 16 volunteers who had a conduction disturbance in the anterior part of the visual pathway (shown with a prolongation of the latency P100 in the visual evoked potentials). The light stimulation was performed with a LED-goggle and a stimulation time each of 10 s "on" and "off" with a frequency of 15 Hz and constant light intensity. We found a reactive increase of the flow velocity of 16% in the control group. The increase begun after a latency of 1,4 s and 1s respectively in this cases who had an increase of flow velocity at the beginning of the flow response. The initial maximum was reached after 5,6 s. Flow velocity begun to decrease 2,9 s after end of light stimulation. There were no significant differences between both groups except for the latencies with increase of flow velocity at the beginning but without initial decrease. Our values were comparable to the values of other studies with similar experimental conditions. Similar patterns of the flow response were described except of the phenomen of the "initial undershoot". We discussed activation of other areas of the brain and a distribution of blood flow there as an explanation. The time resolution of the functional Doppler sonography is suitable to investigate the time course of the cerebral hemodynamic. But it is not sensitive enough to get conduction disturbances in the anterior part of the visual pathway. The method might be used to investigate disturbances in the neurovascular coupling.
40

Acurácia da ultrassonografia transcraniana colorida no diagnóstico de forame oval patente / Transcranal color coded sonography for detection of patent foramen ovale in young patients with stroke

Milena Carvalho Libardi 26 January 2016 (has links)
Introdução:O Forame Oval Patente (FOP) é a comunicação direita-esquerda (CDE) ou shunt direita-esquerda (SDE) mais comum e frequentemente encontrada em adultos jovens com Acidente Vascular Cerebral (AVC) relacionado ao mecanismo de embolia paradoxal. A Ecocardiografia Transesofágia (ETE) é considerada o padrão para visualização direta do FOP. O Doppler Transcraniano com o teste de microbolhas é frequentemente usado para detectar CDE com boa correlação com o ETE para o diagnóstico de FOP. Mais recentemente, a Ultrassonografia Transcraniana Colorida (TCCS) com inclusão do modo-B e fluxo de cor tem superado o DTC (que é realizado \"as cegas\") em muitas aplicações clínicas mas a acurácia do TCCS para a detecção de CDE e FOP não tem sido sistematicamente avaliada. Objetivo: Determinar se o TCCS é uma ferramenta acurada para identificar tanto FOP quanto CDE. Métodos: Foram recrutados 106 pacientes prospectivamente com Acidente Vascular Cerebral Isquêmico menores de 55 anos admitidos na Unidade de Emergência do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto (HCFMRP). Os pacientes foram submetidos aos exames de ETE, DTC e TCCS e todos os exames incluíram a técnica do teste de microbolhas. Os examinadores foram cegos para os resultados desses exames e foi calculado a concordância Kappa de Cohen inter-examinadores para o TCCS e DTC. A acurácia para o TCCS foi calculada em comparação ao ETE. Resultados: Foram detectados CDE em 54 (50.9%) dos pacientes (idade média 43.9 ± 8.2 anos) com Kappa de Cohen de 0.92 (IC 95% 0.78-1.0) quando realizados TCCS e TCD. TEE e TCSS foram positivos em 23/98 (23.4%) e ETE negative em 20/98 (20.4%). Em 30 (28.3%) o ETE revelou FOP. O TCSS teve uma sensibilidade de 88.4%(IC 95% 0.68-0.97) e especificidade de 72.2%(IC 95% 0.60-0.81) e uma razão de verossimilhança positive de 3.18 (IC 95% 2.14-4.73) para o diagnóstico de FOP. Conclusão: TCCS e DTC tiveram excelente concordância. TCCS tem uma boa acurácia para a detecção de FOP e CDE em pacientes jovens com Acidente Vascular Isquêmico / Introduction: Patent Foramen Ovale (PFO) is the most common right-to-left shunt (RLS) and is often found in young patients with stroke related to paradoxical embolism. ContrastEnhanced Transesophageal Echocardiography (TEE) is considered a gold standard to visualize PFO. Transcranial Doppler (TCD) with bubble test is often used to detect RLS with good correlation to TEE for the diagnostic of PFO. More recently, Transcranial Color Coded Sonography (TCCS) which included B-mode and color coded imaging has overcome blind TCD in many clinical applications but the accuracy of TCCS for detection of RLS and PFO has not been systematically evaluated. Hypothesis: To determine if the TCCS is an accurate tool to identify both PFO and RLS. Methods: We investigate 106 patients with ischemic stroke under 55 years-old admitted from 2012 to 2014 in a tertiary academic hospital. Patients were evaluated with TEE, TCD and TCCS, and all exams included a saline bubble test. The examiners were blinded for the other tests results. Kappa agreement was calculated inter-examiners for TCCS and TCD. Accuracy of TCCS was calculated in comparison to TEE. Results: We detected a RLS in 54 (50.9%) patients (age mean 43.9 ± 8.2) with kappa agreement 0.92 (95%CI 0.78-1.0) when performed TCCS and TCD. TEE and TCSS were positive in 23/98 (23.4%) and TEE did not reveal contrast in 20/98 (20.4%). In 30 (28.3%) patients only TEE revealed a PFO. TCSS had a sensitivity of 88.4% (95%CI 0.68-0.97), specificity of 72.2% (95%CI 0.60-0.81) and positive likelihood ratio of 3.18 (2.14-4.73) of the diagnosis of PFO. Conclusion: TCCS and TCD had an excellent agreement. TCCS has a good accuracy for the detection of PFO and RLS in young patients with stroke

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