Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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November 30, 2009
Internal Carotid Artery Agenesis
- Agenesis, aplasia, and hypoplasia of the ICA are rare congenital abnormalities, occurring in less than 0.01% of the population.
- ICA agenesis is usually diagnosed in asymptomatic patients leading to the assumption that there is adequate collateral circulation. However, patients may be diagnosed after ischemic or hemorrhagic strokes or because of complications resulting from associated abnormalities such as cerebral aneurysms.
- The primordial ICA is well defined by the 4th embryonic week, whereas the skull base does not form until the 5-6th weeks of life. Thus, if the embryonic primordium of the ICA fails to develop no carotid canal develops.
- Agenesis of the carotid canal is diagnostic.