title: Influence of perianeurysmal environment on the deformation and bleb formation of the unruptured cerebral aneurysm: assessment with fusion imaging of 3D MR cisternography and 3D MR angiography.
abstract: OBJECTIVE
  Surface irregularity and bleb formation are anatomical factors that are associated with aneurysm rupture. The perianeurysmal environment has been proposed as one factor that may influence aneurysm morphology. We have developed a fusion imaging technique of 3D MR cisternography and angiography that allows clear visualization of an aneurysm and its environment. This technique may prove useful in further understanding of the natural history of intracranial aneurysms.
  
  
  METHODS
  Fusion images of 3D MR cisternography and angiography were reconstructed by a perspective volume-rendering algorithm from the volume datasets of MR cisternography, obtained by a T2-weighted 3D fast spin-echo sequence, and coordinated MR angiography, by a 3D time-of-flight sequence. On the fusion images, the anatomic relationship of an aneurysm to the perianeurysmal structures was assessed, and the influence of perianeurysmal environment on the deformation and bleb formation of the aneurysm was investigated.
  
  
  RESULTS
  Marked and minor deformation and bleb formation of the aneurysmal dome were found at the areas confronted or adjacent to a certain contact with perianeurysmal structures, including cranial nerves, brain parenchyma, cranial base bones, petroclinoidal dural folds, and dura mater.
  
  
  CONCLUSIONS
  Fusion images of 3D MR cisternography and angiography can depict the contact of an aneurysm with its perianeurysmal environment; this may provide an additional parameter in consideration for the natural history of cerebral aneurysms.
authors.affiliation: Department of Neurological Surgery, Ryofukai Satoh Neurosurgical Hospital, Hiroshima, Japan. ucsfbtrc@urban.ne.jp
authors.forename: Toru
authors.initials: T
authors.lastname: Satoh
authors.forename: Megumi
authors.initials: M
authors.lastname: Omi
authors.forename: Chika
authors.initials: C
authors.lastname: Ohsako
authors.forename: Atsushi
authors.initials: A
authors.lastname: Katsumata
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yoshimoto
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuchimoto
authors.forename: Keisuke
authors.initials: K
authors.lastname: Onoda
authors.forename: Koji
authors.initials: K
authors.lastname: Tokunaga
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugiu
authors.forename: Isao
authors.initials: I
authors.lastname: Date
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001921:Brain / Q000473:pathology; D002946:Cisterna Magna / Q000473:pathology*; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged