Carotid Plaque Imaging

Researchers in Medical Physics have collaborated on the development and clinical applications of a number of medical ultrasound imaging techniques including: contrast enhanced imaging; Tissue Doppler Imaging; greyscale image processing; vector Doppler flow imaging; multigate Doppler; shear wave elastography. These enable the measurement of various vascular and physiological parameters with high temporal and spatial resolution. Well equipped labs and ultrasound facilities are available with our collaborators. For example the measurement of flow mediated dilation for assessing endothelial function supports clinical studies in the Department of Cardiovascular Sciences and the Leicester Diabetes Centre. For more information please contact Dr Kumar Ramnarine.

Assessment of Unstable Carotid Plaque

Shear Wave Elastography (SWE)One important clinical application is the use of novel ultrasound techniques to help identify the unstable carotid plaque. A common cause of stroke comes from the build-up of plaque within the carotid artery in the neck. The current process for deciding which patients should be offered surgery to remove the plaque is heavily reliant on ultrasound measurement of blood flow velocity, which is used as a surrogate measure for estimating the degree of narrowing of the artery (stenosis). The degree of stenosis, however, is a poor predictor of individual stroke risk.

In Leicester we are involved in the search for more reliable markers of plaque instability, which we hope will improve clinical decision making for patients with carotid artery disease. Medical Physics researchers work in collaboration with Vascular Surgeons, Stroke Physicians and Clinical Vascular Scientists to develop and evaluate new ultrasound techniques that could help to identify individual patients at risk of plaque rupture by assessing the ultrasonic appearance, dynamic behaviour and elasticity of the plaque. We have acquired a state-of-the-art Supersonic Imagine Aixplorer ultrasound system that utilises a novel technique known as shear wave elastography for assessment of tissue stiffness. Shear wave elastography directly measures Young's Modulus by using ultrafast ultrasound imaging techniques to map the speed of propagation of ultrasonic shear-waves through tissue. We were one of the first centres to investigate possible vascular applications and the first to demonstrate potential clinical benefit to help identify the unstable carotid plaque.

Experimental ultrasound studies

In Leicester we combine clinical in-vivo studies with experimental in-vitro studies to help assess the clinical potential of new ultrasound techniques. Experimental phantoms, test objects, flow models and tissue mimics enable the assessment of novel ultrasound techniques under well controlled laboratory conditions. Researchers in Leicester have developed ultrasound phantoms, test objects and tissue mimicking materials that are well characterised and have been widely adopted in research laboratories worldwide.

For more information please contact Dr Kumar Ramnarine

 

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