title: Agenesis of the internal carotid artery with paraclinoid-supraclinoid anastomosis and basilar artery-posterior communicating artery anastomosis diagnosed by magnetic resonance angiography.
abstract: The several types of agenesis of the internal carotid artery (ICA) are classified based on the aplastic segment of the ICA and types of collateral circulation. On magnetic resonance angiography, we incidentally found an extremely rare case in which the patient had 2 types of collateral circulation-anastomosis between the paraclinoid and supraclinoid segments of the contralateral ICA and anastomosis between the tip of the basilar artery and the posterior communicating artery. This is the first report of a case of ICA agenesis with 2 such types of collateral circulation.
authors.affiliation: Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama, 350-1298, Japan, auchino@saitama-med.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Uchino
authors.forename: Naoko
authors.initials: N
authors.lastname: Saito
authors.forename: Shinya
authors.initials: S
authors.lastname: Kohyama
mesh_terms: D000328:Adult; D001488:Basilar Artery / Q000002:abnormalities*; D002343:Carotid Artery, Internal / Q000002:abnormalities*; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D033162:Incidental Findings; D018810:Magnetic Resonance Angiography