title: Disappearance and reappearance of a cerebral aneurysm: a case report.
abstract: BACKGROUND
  The false-negative rate of DSA in the setting of a ruptured cerebral aneurysm is approximately 15% (Topcuoglu M, Ogilvy C, Carter B, et al. Subarachnoid hemorrhage without evident cause on initial angiography studies: diagnostic yield of subsequent angiography and other neuroimaging tests. J Neurosurg 2003;98:1235-1240). Detecting these aneurysms is imperative to avoid repeat hemorrhage. Rarely, one is able to document the phenomenon of the disappearance and subsequent reappearance of the ruptured aneurysm.
  
  
  METHODS
  This is a case report of subarachnoid hemorrhage (SAH) in which a cerebral aneurysm of the M1 segment of the left proximal middle cerebral artery was initially detected by CTA at an outside hospital only to evade detection with both CTA and DSA at our institution. Repeat DSA 1 week later revealed the culprit aneurysm, which was then treated endovascularly.
  
  
  CONCLUSIONS
  Patients with significant SAH and negative DSA findings should be considered for further diagnostic testing including CTA or repeat DSA. The current literature supports the strategy used at our institution of initial CTA and DSA in the setting of SAH, and then subsequent repeat DSA as warranted if the initial studies are nondiagnostic. Timing of repeat examination, as demonstrated in this case, should favor a shorter time course.
authors.affiliation: Department of Neurology, Division of Interventional Neuroradiology, New York-Presbyterian Hospital, Weill Cornell Medical College, New York, NY 10021, USA. edward.greenberg.98@alumni.brown.edu
authors.forename: Edward
authors.initials: E
authors.lastname: Greenberg
authors.forename: Vallabh
authors.initials: V
authors.lastname: Janardhan
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Katz
authors.forename: Howard
authors.initials: H
authors.lastname: Riina
authors.forename: Robert
authors.initials: R
authors.lastname: Zimmerman
authors.forename: Y Pierre
authors.initials: YP
authors.lastname: Gobin
mesh_terms: D000328:Adult; D015901:Angiography, Digital Subtraction / Q000379:methods / Q000592:standards*; D000800:Angioplasty, Balloon; D042241:Early Diagnosis; D004621:Embolization, Therapeutic; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D011237:Predictive Value of Tests; D012008:Recurrence; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000503:physiopathology; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards*; D016896:Treatment Outcome