title: Internal carotid aplasia/hypoplasia and intracranial saccular aneurysms: series of three new cases and systematic review of the literature.
abstract: OBJECTIVE
  Abnormal arterial flow dynamics and intracranial collateral pathways can be seen in patients with congenital internal carotid artery (ICA) aplasia or hypoplasia. Here we seek to evaluate whether ICA aplasia/hypoplasia is associated with an increased prevalence of intracranial saccular aneurysm relative to carotid rete mirabile.
  
  
  METHODS
  We combined our experience of three cases with 148 previous publications to form a retrospective series including 132 cases of ICA aplasia, 33 cases of ICA hypoplasia, and 34 cases of carotid rete mirabile.
  
  
  RESULTS
  After excluding cases lacking angiograms, ICA aplasia/hypoplasia was more commonly associated with aneurysm (45/158, 27.8%) compared with rete mirabile (2/34, 5.9%). A significantly greater overall aneurysm prevalence was seen among ICA aplasia/hypoplasia patients age 30 years or older (38/101, 36.6%) than in younger individuals (7/48, 14.6%).
  
  
  CONCLUSIONS
  Intracranial saccular aneurysm is more strongly associated with ICA aplasia/hypoplasia than rete mirabile. An increased aneurysm prevalence among older individuals with ICA aplasia/hypoplasia suggests an acquired etiology. Magnetic resonance angiography (MRA) is recommended in the initial evaluation of ICA aplasia/hypoplasia to evaluate for intracranial saccular aneurysm, particularly after the third decade of life.
authors: Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA. waz2002@nyp.org
authors: Walter E
authors: WE
authors: Zink
authors: Ricardo J
authors: RJ
authors: Komotar
authors: Phillip M
authors: PM
authors: Meyers
mesh_terms: D000328:Adult; D015901:Angiography, Digital Subtraction; D001165:Arteriovenous Malformations / Q000175:diagnosis*; D002340:Carotid Artery Diseases / Q000151:congenital / Q000175:diagnosis* / Q000628:therapy; D002343:Carotid Artery, Internal / Q000002:abnormalities* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000628:therapy; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D018616:Ultrasonography, Doppler, Duplex