title: Anatomy and morphology of giant aneurysms--angiographic study of 125 consecutive cases.
abstract: BACKGROUND
  Giant intracranial aneurysms are rare and heterogeneous lesions with complex vascular anatomy. The aim of this retrospective study was to provide a comprehensive description of the anatomical features of giant aneurysms.
  
  
  METHODS
  We identified 125 patients with 129 giant aneurysms (≥ 25 mm) who were treated between 1987 and 2007 at the Department of Neurosurgery of Helsinki University Central Hospital (HUCH). All the imaging studies and medical records were reviewed for relevant information.
  
  
  RESULTS
  The distribution of the giant aneurysms among regions was as follows: internal carotid artery (ICA) 39%, middle cerebral artery (MCA) 32%, vertebrobasilar and posterior cerebral artery (VB-PCA) region 25%, and anterior cerebral artery (ACA) including the anterior communicating artery 5%. The cavernous ICA segment (n = 21, 16%) and the MCA bifurcation (n = 25, 19%) were the most frequent specific locations. Half (n = 11) of all fusiform aneurysms were found in the VB-PCA region. As many as 41 % of the giant MCA aneurysms were ruptured. Major anatomic variations were found in three (2%) and multiple giant aneurysms in three (2%) patients. Wall calcification was noted in 24% and intraluminal thrombosis in 33% of ruptured giant aneurysms (n = 42).
  
  
  CONCLUSIONS
  The majority of giant aneurysms are located in the ICA and MCA regions, while the ACA region is an exceptional site. The MCA region is the most common site for ruptured giant aneurysms. Associated anatomic variations and the multiplicity of giant aneurysms are a rare finding.
authors.affiliation: Department of Neurosurgery, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260, Helsinki, Finland, ville.nurminen@helsinki.fi.
authors.forename: Ville
authors.initials: V
authors.lastname: Nurminen
authors.forename: Martin
authors.initials: M
authors.lastname: Lehecka
authors.forename: Amit
authors.initials: A
authors.lastname: Chakrabarty
authors.forename: Riku
authors.initials: R
authors.lastname: Kivisaari
authors.forename: Hanna
authors.initials: H
authors.lastname: Lehto
authors.forename: Mika
authors.initials: M
authors.lastname: Niemelä
authors.forename: Juha
authors.initials: J
authors.lastname: Hernesniemi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000473:pathology; D020771:Anterior Cerebral Artery / Q000473:pathology*; D002340:Carotid Artery Diseases / Q000473:pathology; D002343:Carotid Artery, Internal / Q000473:pathology*; D002533:Cerebral Angiography / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology*; D012189:Retrospective Studies; D055815:Young Adult