title: Intrinsic, Transitional, and Extrinsic Morphological Factors Associated With Rupture of Intracranial Aneurysms.
abstract: BACKGROUND
  As diagnosis and treatment of unruptured intracranial aneurysms continues to increase, management principles remain largely based on size. This is despite mounting evidence that aneurysm location and other morphologic variables could play a role in predicting overall risk of rupture. Morphological parameters can be divided into 3 main groups, those that are intrinsic to the aneurysm, those that are extrinsic to the aneurysm, and those that involve both the aneurysm and surrounding vasculature (transitional).
  
  
  OBJECTIVE
  We present an evaluation of intrinsic, transitional, and extrinsic factors and their association with ruptured aneurysms.
  
  
  METHODS
  Using preoperative computed tomographic angiography, we generated 3-dimensional models of aneurysms and their surrounding vasculature with Slicer software. Using univariate and multivariate analyses, we examined the association of intrinsic, transitional, and extrinsic aspects of aneurysm morphology with rupture.
  
  
  RESULTS
  Between 2005 and 2013, 227 cerebral aneurysms in 4 locations were evaluated/treated at a single institution, and computed tomographic angiographies of 218 patients (97 unruptured and 130 ruptured) were analyzed. Ruptured aneurysms analyzed were associated with clinical factors of absence of multiple aneurysms and history of no prior rupture, and morphologic factors of greater aspect ratio. On multivariate analysis, aneurysm rupture remained associated with history of no prior rupture, greater flow angle, greater daughter-daughter vessel angle, and smaller parent-daughter vessel angle.
  
  
  CONCLUSIONS
  By studying the morphology of aneurysms and their surrounding vasculature, we identified several parameters associated with ruptured aneurysms that include intrinsic, transitional, and extrinsic factors of cerebral aneurysms and their surrounding vasculature.
authors.affiliation: *Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts; ‡Harvard Medical School, Boston, Massachusetts; §Department of Neurological Surgery, New York-Presbyterian Hospital/Weill Cornell Medical Center, New York, New York.
authors.forename: Allen L
authors.initials: AL
authors.lastname: Ho
authors.forename: Ning
authors.initials: N
authors.lastname: Lin
authors.forename: Kai U
authors.initials: KU
authors.lastname: Frerichs
authors.forename: Rose
authors.initials: R
authors.lastname: Du
mesh_terms: D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000601:surgery; D002533:Cerebral Angiography / Q000379:methods; D019468:Disease Management; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012307:Risk Factors