Non-Invasive Cardiovascular Ultrasound

Glen, Stephen Kenneth (1997) Non-Invasive Cardiovascular Ultrasound. MD thesis, University of Glasgow.

Abstract

This thesis describes the use of non-invasive ultrasound in assessing the cardiovascular system. Ultrasound is one of the most widely used imaging techniques in clinical medicine and recent advances suggest an even greater potential. New developments in ultrasound technology include higher image resolution and faster computer processing. Echocardiography is routinely available in clinical practice and can be used to measure both cardiac structure and function. This well validated technique is applied to an original study of hypertension where measures of left ventricular diastolic function are found to support a change in the management of white coat hypertension. Arterial mechanical function can now be studied non-invasively allowing assessment of arterial compliance by measuring small changes in arterial diameter throughout the cardiac cycle. In addition the tensile stress applied during cardiac contraction can be estimated by measuring systolic and diastolic flow velocities within the vessel. The new technique of arterial wall tracking is described and compared to conventional Doppler examination of the arteries. High resolution ultrasound can provide enough detail to measure the separate layers within arterial walls with a resolution of 0.01mm. This technique is used in a study of atherosclerosis and hypertension where measurements of early atherosclerosis (intima-medial thickness) are compared to plasma markers including lipoprotein (a) and fibrinogen. Computer analysis of Doppler waveforms allows digital visual representation of blood flow. The fast Fourier transformation technique is used in transcranial Doppler ultrasound where low MHz frequency ultrasound is used to penetrate bone allowing monitoring of intracranial blood flow velocities. Continuous digital monitoring of arterial blood flow revealed signals caused by circulating microemboli in subjects with carotid artery stenosis. Transcranial Doppler ultrasound is used in this thesis to study commercial air divers and subjects with carotid atherosclerosis. These disparate groups represent sources of gaseous and solid emboli respectively. Overall the thesis describes the original use of established and new ultrasound techniques which are applicable to clinical practice.

• Item Type: Thesis (MD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Henry Elliott
• Keywords: Medicine, Medical imaging
• Date of Award: 1997
• Depositing User: Enlighten Team
• Unique ID: glathesis:1997-75898
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Dec 2019 09:15
• Last Modified: 19 Dec 2019 09:15
• URI: https://theses.gla.ac.uk/id/eprint/75898