ICA stenosis vs occlusion DSA

ICA stenosis: 

DSAs showing significant ICA stenosis at origin.

Note the sluggish distal filling of the internal carotid artery.








Patients with ICA stenosis often present with transient ischemic attacks, cortical border zone infarcts, amaurosis fugax that is transient monocular blindness which results from reduced blood flow through the ophthalmic artery, the first major branch off the internal carotid artery.
Patient with symptomatic high grade ICA stenosis benefit from stenting compared with conventional medical treatment.



ICA Occlusion: 
DSAs showing complete cut off of ICA at its origin without any distal filling implies to occlusion.

In such patients, the carotid Doppler or MR Angiogram most of the time mentions complete occlusion of ICA. But on DSA there is thin / sluggish distal filling of the internal carotid artery goes in favour of stenosis.
This distinction is important because patients with high grade stenosis benefit from carotid end arterectomy or stenting and those with complete occlusions are not surgical candidates.