Radiologic evaluation of the carotid arteries.

In recent years the radiologist has been faced with a host of new imaging modalities which provide structural as well as physiologic information about the carotid arteries. Although conventional intra-arterial angiography is considered the standard of comparison for precise anatomic definition of the cervical and intracranial carotid arteries, it is being replaced in many instances by other techniques. CT scanning may provide valuable information regarding the relationship of the carotid arteries to soft tissue structures in the neck, and dynamic CT scanning has been used to measure cerebral blood flow. Other noninvasive techniques, such as B-mode scanning and Doppler imaging and spectral analysis, can provide accurate information about carotid stenoses and occlusions, although mostly limited to the region of the common carotid bifurcation. The recent development of digital subtraction intravenous angiography provides a revolutionary new and safe way to evaluate the entire carotid arteries, from their origins to their intracranial branches. The advantages and disadvantages, as well as the current roles of these modalities in the radiologic evaluation of the carotid arteries, will be discussed.