title: Aneurysm permeability following coil embolization: packing density and coil distribution.
abstract: BACKGROUND
  Rates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability.
  
  
  METHODS
  Aneurysm models were coiled using either Guglielmi detachable coils or Target coils. The permeability was assessed by taking the ratio of microspheres passing through the coil mass to those in the working fluid. Aneurysms containing coil masses were sectioned for image analysis to determine surface area fraction and coil uniformity.
  
  
  RESULTS
  All aneurysms were coiled to a packing density of at least 27%. Packing density, surface area fraction of the dome and neck, and uniformity of the dome were significantly correlated (p<0.05). Hence, multivariate principal components-based partial least squares regression models were used to predict permeability. Similar loading vectors were obtained for packing and uniformity measures. Coil mass permeability was modeled better with the inclusion of packing and uniformity measures of the dome (r(2)=0.73) than with packing density alone (r(2)=0.45). The analysis indicates the importance of including a uniformity measure for coil distribution in the dome along with packing measures.
  
  
  CONCLUSIONS
  A densely packed aneurysm with a high degree of coil mass uniformity will reduce permeability.
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Ju-Yu
authors.initials: JY
authors.lastname: Chueh
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Vedantham
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Wakhloo
authors.affiliation: PreClinical Science, Stryker Neurovascular, Fremont, California, USA.
authors.forename: Sarena L
authors.initials: SL
authors.lastname: Carniato
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Ajit S
authors.initials: AS
authors.lastname: Puri
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Conrad
authors.initials: C
authors.lastname: Bzura
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Coffin
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Bogdanov
authors.affiliation: Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gounis
mesh_terms: D002560:Cerebrovascular Circulation; D004621:Embolization, Therapeutic / Q000379:methods*; D006801:Humans; D002532:Intracranial Aneurysm / Q000473:pathology / Q000628:therapy*; D008953:Models, Anatomic; D010539:Permeability; D016896:Treatment Outcome
keywords: Aneurysm; Coil; Intervention