Congenital absence of the internal carotid artery with associated aneurysms
Presentation
Headache.
Patient Data
The petrous, cavernous, and terminal segments of the right internal carotid artery are not clearly identified in the axial T2. The distal A1 segment of the left anterior cerebral artery appears mildly dilated.
Bilateral cerebral white matter mainly the centra semiovale and high frontoparietal regions multiple nonspecific foci of abnormal signal elicit high signal in T2 and FLAIR with no surrounding edema or associated mass effect.
The right common carotid artery is relatively smaller than the left artery.
The cervical segment of the right internal carotid artery appears markedly hypoplastic/ aplastic. The remaining arterial segments couldn’t be clearly visualized consistently with a congenital absence.
The right external carotid artery and its branches look normal.
Two small aneurysms are seen bilaterally at the A1/ACOM junction measure about 5mm.
The annotated images highlight the aneurysms.
Case Discussion
Congenital absence of the internal carotid artery (ICA) is a rare anomaly that occurs in less than 0.01% of the population. It encompasses agenesis, aplasia, and hypoplasia.
Although many of these cases remain asymptomatic and go undetected, it is associated with cerebral aneurysms like in this case.
Vascular assessment should be done routinely in the conventional MRI of the brain. For arteries, T2 is the best.
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