title: Rebleeding of aneurysmal subarachnoid hemorrhage in computed tomography angiography:  risk factor, rebleeding pattern, and outcome analysis.
abstract: OBJECTIVE
  For patients with subarachnoid hemorrhage (SAH), computed tomography angiography (CTA) has been the first imaging modality for aneurysm detection. We evaluate the rate, time distribution, risk factors, and clinical outcome of aneurysmal rebleeding by CTA findings.
  
  
  METHODS
  Consecutive patients with SAH presenting to our hospital, a tertiary care hospital, were retrospectively included. We reviewed images for all patients receiving an initial noncontrast computed tomography scan and further CTA for nontraumatic SAH surveillance with focus on rebleeding evidence.
  
  
  RESULTS
  A total of 12 patients with early aneurysmal rebleeding (12/110 patients [10.9%]) within 6 hours after emergency room arrival were found with dismal outcome (50% mortality) and 3 rebleeding patterns: pattern 1 of rapid active bleeding with contrast extravasation, pattern 2 of slow active bleeding with contrast leakage in the delayed venous phase, and pattern 3 of hematoma enlargement. The risk factor and poor prognostic sign include larger aneurysm diameter (≧7 mm) and contrast extravasation during CTA.
  
  
  CONCLUSIONS
  Rebleeding rate of aneurysmal SAH in the hyperacute stage at less than 6 hours is 10.9% with poor prognosis in this study, especially in patients with active bleeding demonstrated in CTA.
authors.affiliation: Department of Radiology, Chi-Mei Medical Center, Tainan, Taiwan.
authors.forename: Te-Chang
authors.initials: TC
authors.lastname: Wu
authors.forename: Yu-Kun
authors.initials: YK
authors.lastname: Tsui
authors.forename: Tai-Yuan
authors.initials: TY
authors.lastname: Chen
authors.forename: Chien-Jen
authors.initials: CJ
authors.lastname: Lin
authors.forename: Tai-Ching
authors.initials: TC
authors.lastname: Wu
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Tzeng
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017542:Aneurysm, Ruptured / Q000150:complications* / Q000000981:diagnostic imaging* / Q000401:mortality; D002533:Cerebral Angiography / Q000379:methods*; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000401:mortality; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome