There is a critical stenosis of the proximal cervical right internal carotid artery and small caliber of the distal vessel compared to the contralateral side and to the external carotid artery. The intracranial right internal carotid artery attenuation is less than that of the left, suggesting differential peak contrast bolus arrival. Together, the findings are consistent with right carotid near-occlusion with partial collapse.
Thin slice (0.625 mm) axial images through the carotid bifurcations and curved planar reformations (CPR) of the right internal carotid artery (RICA) best demonstrate the finding.
The left internal carotid artery origin shows only mild (<50%) stenosis, taking the normal distal vessel diameter as the denominator.