Abstract
Internal carotid artery (ICA) is a rare anomaly of embryologic development. Digital
subtraction angiography examination showed no visualization of the ICA on the right
side in a 30-year-old male patient and on the left side in a 47-year-old female patient.
Computed tomography (CT) revealed the absence of the corresponding bony carotid canal.
Doppler examinations of the common carotid and external carotid arteries on the affected
sides demonstrated high-resistance flow characteristics. Two cases of ICA agenesis
with subarachnoid hemorrhage were presented and the literature is reviewed.
