title: Utility of CT angiography in the identification and characterization of supraclinoid internal carotid artery blister aneurysms.
abstract: OBJECTIVE
  Blister aneurysms of the supraclinoid ICA represent a rare but potentially catastrophic cause of SAH, often presenting both diagnostic and therapeutic dilemmas. We explore the utility of CTA in the identification and characterization of ICA blister aneurysms.
  
  
  METHODS
  We performed a retrospective review of catheter cerebral angiograms obtained at our institution over a 12-month period for evaluation of SAH, identifying 6 cases of ICA blister aneurysms. All patients underwent CTA and DSA for evaluation of SAH. The reports from the CTA and DSA studies were reviewed to identify aneurysms correctly diagnosed prospectively. Retrospective review of the CTA and DSA images was also performed. Review of the interpretations and images was performed for any follow-up studies.
  
  
  RESULTS
  All 6 patients presented with SAH, diagnosed by head CT. All patients subsequently underwent CTA prior to DSA evaluation. All 6 aneurysms were identified prospectively on initial DSA imaging. Of the 6 blister aneurysms, 4 (67%) were identified prospectively; and 5 (83%), retrospectively on CTA. All 6 patients underwent endovascular treatment with stent placement. Four of the 6 aneurysms underwent follow-up CTA (range, 9-22 days), including the 2 aneurysms that had been unidentifiable preprocedurally. All 4 blister aneurysms were seen postprocedurally by DSA. Three of these 4 (75%) residual aneurysms were detected by CTA (both prospectively and retrospectively).
  
  
  CONCLUSIONS
  In the presence of SAH and otherwise negative findings on CTA, a catheter cerebral angiogram should be performed to absolutely exclude an ICA blister aneurysm.
authors: Department of Radiology, University of Virginia Health System, Charlottesville, USA. jrg4@virginia.edu
authors: J R
authors: JR
authors: Gaughen
authors: P
authors: P
authors: Raghavan
authors: M E
authors: ME
authors: Jensen
authors: D
authors: D
authors: Hasan
authors: A N
authors: AN
authors: Pfeffer
authors: A J
authors: AJ
authors: Evans
mesh_terms: D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000000981:diagnostic imaging* / Q000628:therapy; D015901:Angiography, Digital Subtraction; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000628:therapy; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D003937:Diagnosis, Differential; D004621:Embolization, Therapeutic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D015607:Stents; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000628:therapy; D014057:Tomography, X-Ray Computed / Q000379:methods*