Characterisation of the atheromatous plaque in the carotid arteries.

Ultrasound duplex scanning is one of the major methods for the study of the development of the atherosclerotic plaque. The pulsed Doppler flowmeter can be used to investigate the flow disturbance caused by the presence of the atherosclerotic plaque in the flow lumen. The high resolution image capability means that the morphology and structure of the plaque may be studied in detail and comparisons made between the ultrasound appearance and histology, at carotid endarterectomy. The real-time image capability allows the study of the motion of the plaque over the cardiac cycle. The bending and shearing motions observed in some plaques may be a contributory factor to the fissuring and cracking, ulceration and intra-plaque haemorrhage, observed. It is felt that the dynamics of the plaque and its environment have largely been overlooked and that in order to investigate further the natural history of the plaque, it is necessary to investigate plaque morphology and structure, plaque dynamics, and the consequent flow disturbance.