title: CT angiography for evaluation of cerebral vasospasm following acute subarachnoid haemorrhage.
abstract: BACKGROUND
  Cerebral vasospasm (CV) is one of the most dreaded complications in patients who survive acute subarachnoid haemorrhage (SAH), and conventional cerebral angiography (DSA) is the gold standard for its diagnosis. We evaluated CT angiography (CTA) as a non-invasive alternative for diagnosis of CV and assessed if CTA could have a role in choosing appropriate treatment.
  
  
  METHODS
  Consecutive patients with SAH and suspected vasospasm were included when DSA was performed within 24 h from CTA. Two neuro-radiologists retrospectively analysed CTA and DSA studies independently. Assessment included presence of central and peripheral vasospasm and grading of severity of central CV. A treatment recommendation based on CTA was compared to actual treatment received.
  
  
  RESULTS
  Final analysis included 34 patients. CTA was more accurate for diagnosis of central then for peripheral CV with high sensitivity (reader 1, 91%; reader 2, 92%), specificity (reader 1, 73%; reader 2, 90%), accuracy, positive predictive value and negative predictive value for central vasospasm. For grading the severity of CV CTA's sensitivity, specificity and accuracy were high for most central arteries. The reader's recommendation of angioplasty according to CTA was significantly predictive of actual receipt of angioplasty but overestimated actual receipt of triple H treatment.
  
  
  CONCLUSIONS
  CTA is adequate for detecting central vasospasm in symptomatic SAH patients. A negative result should not prevent further investigation especially when evaluating arterial segments adjacent to metal artefacts from coils or clips. CTA is helpful in treatment decision making specifically regarding the need for balloon angioplasty.
authors.affiliation: Division of Neuroradiology, Department of Diagnostic Imaging, QEII Health Sciences Center, Dalhousie University, Halifax, Canada. shivajai1@rediffmail.com
authors.forename: Jai Jai Shiva
authors.initials: JJ
authors.lastname: Shankar
authors.forename: Irene Y L
authors.initials: IY
authors.lastname: Tan
authors.forename: Timo
authors.initials: T
authors.lastname: Krings
authors.forename: Karel
authors.initials: K
authors.lastname: Terbrugge
authors.forename: Ronit
authors.initials: R
authors.lastname: Agid
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography / Q000379:methods*; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging* / Q000628:therapy; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000628:therapy
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol