Cerebral ischaemia secondary to arterial occlusion or rupture is known as cerebral stroke. Stroke secondary to atherosclerotic disease is the third leading cause of death in the United States. Many stroke victims survive the catastrophic event with some degree of neurologic impairment. More than 500,000 new cases of cerebrovascular accident are reported annually. Thus early and accurate diagnosis of carotid artery disease is essential for such patients. Non-invasive imaging techniques (namely CT, MR, and Doppler US) are the current methods used for evaluating carotid artery diseases. Yet, these methods show different degrees of specificity and sensitivity regarding: The estimation of the degree of stenosis. The depiction of arterial wall calcification, intimal thickening, ulcers and plaque ; the detection of arterial wall dissection aneurysms and vasculitis ; surgical planning and even post- operative evaluation. The degree of stenosis is best estimated by hard 3D CTA especially using maximum intensity projection method. On the other hand, stenosis was generally over estimated by MRA however MRA has the advantage of scanning the carotid siphon. In conclusion helical CT is versatile imaging system that is gaining increase popularity for the non-invasive imaging of vascular study, its advantage include speed of imaging, standardizing the imaging protocol and in addition because the intravascular data reflect volume of contrast and relatively independent of flow; helical CT is the non-invasive study of choice for extreme stenosis, tortuous vessels, and structures with slow intravascular flow.