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 60 for “"Doppler ultrasound"”.
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Power doppler ultrasound for peripheral perfusion imaging
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Contrast-enhanced Doppler Ultrasound Imaging using Plane Waves
… and vascular imaging simultaneously. In ultrasound, Doppler can visualize veins and arteries, but cannot detect the capillary level perfusion. Conversely, microbubble contrast-enhanced ultrasound imaging enables low velocity perfusion to be detected and separated from the tissue echo, but …
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Channel characterisation and modelling for transcranial Doppler ultrasound.
… (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 been …
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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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Local measurement of the pulse wave velocity using Doppler ultrasound
… from the blood flow waveforms acquired by Doppler ultrasound. The proposed method includes the following steps: first acquire flow waveforms by Doppler ultrasound at two locations within the same artery, next detect the delay or difference in arrival time of the flow wave at the two …
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Development of a method for calculation of cardiac output using Doppler ultrasound
… of blood pumped by the heart in one minute. The Doppler effect can be used to measure cardiac output by measuring the peak frequency, which is directly proportional to the velocity of blood flowing in the aorta, associated with the Doppler shift signal when an ultrasound beam is incident on the …
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Perfusion imaging using power doppler ultrasound without contrast enhancement to diagnose peripheral artery disease
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo terms
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Perfusion imaging using power doppler ultrasound without contrast enhancement to diagnose peripheral artery disease
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2024-09-16 without embargo terms
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Spatiotemporal excitation sequence manipulation and processing for Doppler ultrasound and pulse-echo sound speed imaging applications
… the maximum detectable velocity in pulsed-wave Doppler ultrasound. This is achieved by a reordering of the frames to minimize the relative phase difference between them while preserving spatial resolution that could be expected using a traditional sequence. The second application, and arguably …
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Time-frequency Analysis of Doppler Ultrasound Blood Flow Signals: An Investigation into Automated Diagnosis of Vascular Disease
… classification and diagnosis process for Doppler ultrasound blood flow signals to support clinical decision making. This process is used in this study to diagnose the severity of vascular disease in the lower limb. The study reviewed the existing methods for clinical decision making and …
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Clinical utility of 3D power doppler ultrasound and maternal biomarkers in the prediction of pre-eclampsia in high-risk pregnancies
… screening tool combining medical history, ultrasound parameters and serum biomarkers may be of use in defining the patient-specific risk for pre-eclampsia.<br/><br/>Against this background, this thesis examines the ability of baseline maternal characteristics, placental vascularisation …
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Doppler ultrasound technique used to determine the blood flow viscosity in the middle cerebral artery of a canine animal model
… of an canine animal model was measured using the Doppler Ultrasound technique. A transducer was designed with a 20 MHz piezoelectric crystal and used for the application. An in vitro calibration system was designed and machined for the purpose of testing and calibrating every transducer before …
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An assessment of the role of Doppler ultrasound velocity waveform analysis of the umbilical artery in the diagnosis of fetal distress in labour
Introduction: An assessment of the role of Doppler ultrasound velocity waveform analysis of the fetal umbilical arteries in the diagnosis of fetal distress in labour is made from a review of the literature and clinical study. Study objectives: 1) To determine the value of screening with Doppler …
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Reproducibility of a continuous-wave Doppler ultrasound system for assessment of ascending aortic blood flow responses during graded exercise testing with healthy individuals
Continuous-wave (CW) Doppler recordings of ascending aortic maximal blood flow acceleration (PkA), maximal velocity (PkV) and systolic velocity integral (SVI) were taken at each stage of a graded exercise treadmill test on two separate days with 30 physically active adult males. Signals were …
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Theoretical and technical aspects of using the Doppler umbilical flow waveform to assess compromised foetal circulation
… flow waveform, obtained clinically with Doppler ultrasound, to monitor the condition growth impaired foetuses. This aim was addressed via the following . 1. Survey the literature to obtain information regarding : a) the foetal blood flow distribution for normal foetuses. b) the effect of …
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The use of ultrasound in the prediction of endometrial cancer in women with postmenopausal bleeding
… presented in this thesis was to identify the ultrasound methods and ultrasound features that are most useful for the prediction of endometrial cancer in patients with postmenopausal bleeding and sonographic endometrial thickness 4.5 mm or more. The grey-scale ultrasound variable that best …
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