title: The bihemispheric posterior inferior cerebellar artery.
abstract: Rarely, a solitary posterior inferior cerebellar artery (PICA) will supply both cerebellar hemispheres. We report four cases of this variant. We present a retrospective review of clinical information and imaging of patients undergoing angiography at our institution to identify patients with a bihemispheric PICA. There were four patients: three males and one female. One patient presented with a ruptured arteriovenous malformation, and one with a ruptured aneurysm. Two patients had normal angiograms. The bihemispheric PICA was an incidental finding in all cases. The bihemispheric vessel arose from the dominant left vertebral artery, and the contralateral posterior inferior cerebellar artery was absent or hypoplastic. In all cases, contralateral cerebellar supply arose from a continuation of the ipsilateral PICA distal to the choroidal point and which crossed the midline dorsal to the vermis. We conclude that the PICA may supply both cerebellar hemispheres. This rare anatomic variant should be considered when evaluating patients with posterior fossa neurovascular disease.
authors.affiliation: Department of Radiology and Neurosurgery, Brigham and Women's Hospital and Children's Hospital, Boston, MA, USA.
authors.forename: Sean P
authors.initials: SP
authors.lastname: Cullen
authors.forename: Augustin
authors.initials: A
authors.lastname: Ozanne
authors.forename: Hortensia
authors.initials: H
authors.lastname: Alvarez
authors.forename: Pierre
authors.initials: P
authors.lastname: Lasjaunias
mesh_terms: D000293:Adolescent; D000328:Adult; D017542:Aneurysm, Ruptured / Q000175:diagnosis; D001165:Arteriovenous Malformations / Q000175:diagnosis; D002531:Cerebellum / Q000098:blood supply*; D002533:Cerebral Angiography; D002675:Child, Preschool; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D020769:Posterior Cerebral Artery / Q000002:abnormalities*; D012189:Retrospective Studies