Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"transcranial Doppler"”.
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Channel characterisation and modelling for transcranial Doppler ultrasound.
… signals (MES) is a mature application of transcranial Doppler (TCD) ultrasound. It involves the identification of abnormally highpitched signals within the arterial waveform as a method of diagnosis and prediction of embolic complications in stroke patients. More recently, algorithms have …
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An electronically steered, wearable transcranial doppler ultrasound system
This thesis details the design of a transcranial Doppler (TCD) ultrasound system to measure cerebral blood flow velocity (CBFV) at the middle cerebral artery (MCA). TCD sonography has been clinically indicated in a variety of neurovascular diagnostic applications. Acceptance of conventional TCD …
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A wearable Transcranial Doppler ultrasound phased array system
Transcranial Doppler (TCD) sonography is a specialized ultrasound technique that enables measurement of blood ow velocity from the basal intracerebral vessels. Use of TCD sonography is highly compelling as a diagnostic modality due to its safety in prolonged studies, high temporal resolution, and …
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NON-INVASIVE MONITORING OF INTRACRANIAL PRESSURE USING TRANSCRANIAL DOPPLER ULTRASONOGRAPHY
… the assessment, applications and development of transcranial Doppler (TCD)-based non-invasive methods for ICP and cerebral perfusion pressure (CPP) monitoring. The thesis is divided into three sections: I) The accuracy of existing TCD-based nICP estimators in various scenarios of varying ICP …
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Transcranial Doppler sonography: a new noninvasive method for measuring toxicant-induced alterations in cerebral blood flow
<p>The purpose of this experiment was to use transcranial Doppler sonography (TCD) in the dog to noninvasively measure changes in cerebral blood flow (CBF) resulting from a low-level exposure to the commonly used pyrethroid insecticide deltamethrin. Deltamethrin has previously been shown to …
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Multimodality monitoring in paediatric severe traumatic brain injury : the contributions of brain oxygen, transcranial doppler and autoregulation monitoring to conventional methods on monitoring
Traumatic brain injury (TBI) is a highly complex clinical condition in the most complex organ of the body. The foundation of care of the patient with severe TBI is the prevention of secondary insults to the brain. This relies on conventional monitoring tools to identify patients at risk, but often …
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Lipid Micro Emboli in Cardiac Surgery
… registering micro embolic signals from a transcranial Doppler and counting lipid micro emboli in blood samples taken from the arterial line, we found a strong correlation between the two phenomena. Lipid material was also tagged by beta radioactivity and found to end up in different …
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Deep Multimodal Physiological Learning of Cerebral Vasoregulation Dynamics on Stroke Patients Towards Precision Brain Medicine
… database like Electrocardio-gram (ECG), Transcranial Doppler (TCD), Electromyogram (EMG), and Blood Pressure(BP) as stroke or non-stroke subjects. The effectiveness of these algorithms is demonstrated by a classification accuracy of 90% for the combination of ECG and EMG signals. …
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The impact of ischaemic preconditioning on cerebrovascular function in healthy individuals.
… to a pressure of 10 mmHg. CBF was measured using transcranial Doppler ultrasonography. Cerebral autoregulation was assessed using the squat to stand technique (5 second squat-5 second stand) while cerebral CO2 reactivity was assessed via a period of hypercapnia involving inhalation of 5% CO2. …
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When working towards an optimised Carotid stenting procedure does patient, procedural and pharmacological selection impact on outcome.
… in response to clopidogrel on outcomes. Using transcranial Doppler detected embolic events as a clinical endpoint for comparison with the clopidogrel dependant pathways of platelet activation the study hoped to show a direct effect of the degree of platelet inhibition on the number of emboli …
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Effect of head elevation on intracranial blood flow velocity following acute ischemic stroke
… patients presenting with acute ischemic stroke. Transcranial Doppler (TCD) sonography mounted by head frame was used to measure MCA MFV. Patients were on average 59.5 years of age (SD = 15.4), with a mean National Institutes of Health Stroke Scale score of 11.95 (SD = 6.46) indicating moderate to …
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Do abnormalities in dynamic cerebral auto-regulation underlie the pathophysiological processes behind syncope in older people?
… PPH study maximum 60 minutes per visit). All had Transcranial Doppler ultrasound, beat-to-beat BP, ECG and CO2 monitoring. Baseline autonomic function, arterial stiffness, cardiac baroreceptor sensitivity (BRS) were calculated and dynamic cerebral auto-regulation (as the autoregulatory index ARI) …
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Clinical Applications of Neuromonitoring Following Acute Brain Injury
… (ICP), arterial blood pressure (ABP), and transcranial Doppler ultrasonography (TCD) recordings. Data analysis focused on ICP microsensor accuracy, compensatory reserve, the pulsatility of brain signals (ICP and TCD), and cerebral arterial blood volume (CaBV) based on TCD. The main results …
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The effect of sedentary behaviour on cardiovascular biomarkers in active, healthy adults
… were assessed via applanation tonometry and transcranial Doppler ultrasonography respectively. Continuous blood pressure and carotid artery reactivity (via ultrasound) were recorded during the cold pressor test (CPT). During visit two, cardiorespiratory fitness (CRF; VO2peak) was assessed …
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Cerebral Hemodynamics in High-Risk Neonates Probed by Diffuse Optical Spectroscopies
… in the middle cerebral artery acquired by transcranial Doppler ultrasound. In patients with congenital heart defects DCS-measured relative changes in CBF due to hypercapnia agree strongly with relative changes in blood flow in the jugular veins as measured by phase-encoded velocity mapping …
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Impact of Hydroxyurea on Neurocognitive Function and Quality of Life in Children with Sickle Cell Anemia
… recognized. Early screening for stroke risk with Transcranial Doppler ultrasound (TCD) and initiation of monthly red blood cell transfusions in children with SCA and abnormal TCD velocities has been proven to substantially decrease the risk of overt stroke; however, chronic transfusion is …
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Cerebral autoregulation in children with traumatic brain injury: Comparing the autoregulatory index (ARI) to pressure reactivity index (PRx) and their associations with cerebral physiological parameters
… of blood pressure to evaluate changes in transcranial Doppler-derived flow velocity of the middle cerebral artery. Concomitant recordings were made of ICP, PbtO2, and loCBF. Secondly, we also calculated the PRx as a moving correlation co-efficient between slow changes in blood pressure and …
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Continuous Multi-Modal Monitoring of Cerebrovascular Reactivity in Adult Traumatic Brain Injury
… various populations of adult TBI patients. Transcranial Doppler (TCD) based systolic flow index is most closely associated with ICP indices, while cortical autoregulation (measured using laser Doppler) is more closely linked to mean flow index. Given these relationships and the potential for …
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Intracranial hypertension in Kenyan children with cerebral malaria
… the basal cranial arteries were monitored with transcranial Doppler (TCD) sonography. Three children with severe intracranial hypertension (maximum ICP > 60 mmHg and minimum cerebral perfusion pressure (CPP) < 40 mmHg) had a poor outcome despite aggressive therapy with mannitol. One child with a …
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Neurovascular implications of life-long exposure to contact in rugby union; the link to cognition
… and S-nitrosothiols [RSNO]) were obtained. Transcranial Doppler (TCD) ultrasonography was used to determine cerebral perfusion via middle cerebral artery velocity (MCAv). The range of cerebrovascular reactivity to changes in end tidal carbon dioxide (CVRCO2RANGE) was assessed using …
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