[Study of the carotid artery bifurcation using a helical scanner].

Helical CT is a new technology leading to a rapid acquisition of a large volume during the peak of intravascular enhancement. Indications are large in vascular pathology due to the possibilities of three dimensional (3D) reconstructions providing angiogram-like images. To assess carotid bifurcations, this examination needs the choice of multiple parameters for acquisition (collimation, table speed, can time), injection (volume of contrast material, rate, scan delay) and reconstruction (increment, field of view). Post processing is performed on an independent workstation. Helical CT provides a reliable analysis of carotid artery stenosis. Voluminous calcified plaques constitute the main limiting factor preventing image analysis on the 3D reconstructions. Furthermore, image reconstructions require a long time, study of carotid siphons remains inefficient and examination of the circle of Willis cannot be performed in the same time.