Presentation
Patient presents with sudden onset visual loss left eye. O/E left retinal arterial occlusion, ? source of embolus
Patient Data
High-grade stenosis due to a calcified plaque at the origin of the left internal carotid artery. Note the internal carotid above this lesion remains patent but of reduced caliber (4.3 v 2.7 mm) and shows reduced enhancement in the terminal L ICA = 287 HU compared with R ICS = 437 HU.
Case Discussion
One indication that I use to determine the severity of internal carotid stenosis is the differential enhancement in the distal carotid lumens (beyond the stenosis). In this case, there is a 34% reduction, in contrast, density on the left c/w the right. The internal carotid artery beyond the stenosis is also of reduced caliber compared with the right due to the reduced blood flow.