title: Differentiation between intradural and extradural locations of juxta-dural ring aneurysms by using contrast-enhanced 3-dimensional time-of-flight magnetic resonance angiography.
abstract: BACKGROUND
  Juxta-dural ring aneurysms of the ICA have different clinical outcomes and risks for SAH, which are dependent on their position in the intradural or extradural space. The aim of this study was to reveal the precise location of such aneurysms by using CE-MRA.
  
  
  METHODS
  Contrast-enhanced MRA studies were performed in 21 patients with 24 juxta-dural ring aneurysms. The locations were evaluated by source images of CE-MRA and MPR images. We evaluated the accuracy of preoperative MRI findings by comparing imaging results with intraoperative findings in 7 cases.
  
  
  RESULTS
  The CS was clearly enhanced in the CE-MRA technique, which allowed the precise identification of these aneurysms as intradural or extradural. Intracavernous aneurysms were diagnosed when the greater hyperintensity of the aneurysm was located within the less hyperintense region of the contrast-enhanced CS. Nine of the cases were diagnosed as intradural aneurysms, and 15 aneurysms were noted as extradural based on the findings of CE-MRA. Surgery was performed in 7 cases, which included 4 intradural and 3 extradural aneurysms, and the preoperative MRI findings corresponded with the intraoperative findings in all cases.
  
  
  CONCLUSIONS
  Contrast-enhanced MRA and MPR are very useful techniques for determining the location of juxta-dural ring aneurysms.
authors.affiliation: Department of Neurosurgery, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan. ttsuboi-nsu@umin.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tsuboi
authors.forename: Koji
authors.initials: K
authors.lastname: Tokunaga
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shingo
authors.forename: Takahiko
authors.initials: T
authors.lastname: Itoh
authors.forename: Shinya
authors.initials: S
authors.lastname: Mandai
authors.forename: Kazushi
authors.initials: K
authors.lastname: Kinugasa
authors.forename: Isao
authors.initials: I
authors.lastname: Date
mesh_terms: D000328:Adult; D000368:Aged; D002343:Carotid Artery, Internal; D003287:Contrast Media; D003937:Diagnosis, Differential; D004388:Dura Mater; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000601:surgery; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA