title: Prevalence of arterial branches arising from the extracranial internal carotid artery on CT angiography.
abstract: Although it is well known that arterial branches may rarely arise from the cervical internal carotid artery (ICA), their incidence has not been adequately evaluated on computed tomography angiography (CTA). We investigate the prevalence of congenital and non-congenital anomalous branches arising from the cervical ICA by a 5 year retrospective review of neck CTAs performed on 2,602 patients. We found a higher frequency of arteries arising from the ICA than suggested by the existing literature, including a 0.49 % prevalence of the occipital artery origin and a 6.25 % prevalence of the superior pharyngeal branch of (the pharyngeal trunk of) the ascending pharyngeal artery. In addition, six cases of recanalized intersegmental arteries providing collateral flow to the cervical ICA from the cervical vertebral artery were identified. This is the first large, retrospective CTA study evaluating the incidence of these anomalous vessel origins.
authors.affiliation: Tufts University School of Medicine, Lahey Clinic, 41 Mall Road, Burlington, MA, 01805, USA, Juan.E.Small@Lahey.org.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Small
authors.forename: Justin
authors.initials: J
authors.lastname: Harrington
authors.forename: Evan
authors.initials: E
authors.lastname: Watkins
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000000981:diagnostic imaging; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed