What are current preprocedure imaging requirements for carotid artery stenting and carotid endarterectomy: have magnetic resonance angiography and computed tomographic angiography made a difference?

Determination of degree of carotid artery stenosis is of critical importance when deciding whether a patient warrants surgical intervention. While angiography is still considered by some to be the true reference standard for imaging the internal carotid artery (ICA), physicians rely most commonly on duplex imaging when planning for endarterectomy. It is noninvasive, safe, and overall reliable for grading stenosis but is nevertheless user-dependent and can be limited in cases of severe calcification. Moreover, a lack of consensus for duplex criteria can be confounding. In recent years, magnetic resonance angiography (MRA) and computed tomographic angiography (CTA) have assumed a more prominent role in the preoperative planning for treatment of carotid stenosis. Improved resolution and faster acquisition times for both of these imaging modalities have allowed for accurate depictions of degree of stenosis, as well as plaque characterization. CTA and MRA may have special relevance in the era of carotid stenting, since challenging arch anatomy and identification of a high-risk vulnerable plaque may be useful when deciding whether to perform a stent procedure or endarterectomy.