title: Monitoring serial change in the lumen and outer wall of vertebrobasilar aneurysms.
abstract: OBJECTIVE
  Estimation of the stability of fusiform aneurysms of the basilar artery requires precise monitoring of the luminal and outer wall volumes. In this report we describe the use of MR imaging and 3D postprocessing methods to study the evolution of those aneurysms.
  
  
  METHODS
  Nine patients with fusiform basilar artery aneurysms underwent MR imaging studies covering at least 2 different time points (mean delay between studies, 7.1 +/- 4.6 months). Imaging included multisection 2D T1-weighted fast spin-echo and/or 3D steady-state imaging to assess the outer wall and contrast-enhanced MR angiography to study the lumen. The outer and inner walls were extracted using, respectively, a manual delineation (made by 2 observers) and a thresholding technique. The 2 studies were subsequently coregistered at each time point, as well as between differing time points. Volumes of each vessel component were calculated.
  
  
  RESULTS
  Mean volume was 6760 +/- 6620 mm(3) for the outer wall and 2060 +/- 1200 mm(3) for the lumen. Evolution of the lumen and outer wall was highly variable from 1 patient to another, with a trend toward increase of the vessel wall for the largest aneurysms. Interobserver reproducibility for outer wall delineation was on the order of 90%.
  
  
  CONCLUSIONS
  Combining MR imaging methods to study both the outer wall and lumen with 3D registration tools provides a powerful method for progression of fusiform basilar aneurysmal disease.
authors.affiliation: Radiology Service, VA Medical Center, San Francisco, CA 94121, USA. loic.boussel@gmail.com
authors.forename: L
authors.initials: L
authors.lastname: Boussel
authors.forename: M
authors.initials: M
authors.lastname: Wintermark
authors.forename: A
authors.initials: A
authors.lastname: Martin
authors.forename: B
authors.initials: B
authors.lastname: Dispensa
authors.forename: R
authors.initials: R
authors.lastname: VanTijen
authors.forename: J
authors.initials: J
authors.lastname: Leach
authors.forename: V
authors.initials: V
authors.lastname: Rayz
authors.forename: G
authors.initials: G
authors.lastname: Acevedo-Bolton
authors.forename: M
authors.initials: M
authors.lastname: Lawton
authors.forename: R
authors.initials: R
authors.lastname: Higashida
authors.forename: W S
authors.initials: WS
authors.lastname: Smith
authors.forename: W L
authors.initials: WL
authors.lastname: Young
authors.forename: D
authors.initials: D
authors.lastname: Saloner
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014715:Vertebrobasilar Insufficiency / Q000175:diagnosis*