title: Diagnosing delayed cerebral ischemia with different CT modalities in patients with subarachnoid hemorrhage with clinical deterioration.
abstract: OBJECTIVE
  Delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage worsens the prognosis and is difficult to diagnose. We investigated the diagnostic value of noncontrast CT (NCT), CT perfusion (CTP), and CT angiography (CTA) for DCI after clinical deterioration in patients with subarachnoid hemorrhage.
  
  
  METHODS
  We prospectively enrolled 42 patients with subarachnoid hemorrhage with clinical deterioration suspect for DCI (new focal deficit or Glasgow Coma Scale decrease >or=2 points) within 21 days after hemorrhage. All patients underwent NCT, CTP, and CTA scans on admission and directly after clinical deterioration. The gold standard was the clinical diagnosis DCI made retrospectively by 2 neurologists who interpreted all clinical data, except CTP and CTA, to rule out other causes for the deterioration. Radiologists interpreted NCT and CTP images for signs of ischemia (NCT) or hypoperfusion (CTP) not localized in the neurosurgical trajectory or around intracerebral hematomas, and CTA images for presence of vasospasm. Diagnostic values for DCI of NCT, CTP, and CTA were assessed by calculating sensitivities, specificities, positive predictive values, and negative predictive values with 95% CIs.
  
  
  RESULTS
  In 3 patients with clinical deterioration, imaging failed due to motion artifacts. Of the remaining 39 patients, 25 had DCI and 14 did not. NCT had a sensitivity of 0.56 (95% CI, 0.37 to 0.73), specificity=0.71 (0.57 to 0.77), positive predictive value=0.78 (0.55 to 0.91), negative predictive value=0.48 (0.28 to 0.68); CTP: sensitivity=0.84 (0.65 to 0.94), specificity=0.79 (0.52 to 0.92), positive predictive value=0.88 (0.69 to 0.96), negative predictive value=0.73 (0.48 to 0.89); CTA: sensitivity=0.64 (0.45 to 0.80), specificity=0.50 (0.27 to 0.73), positive predictive value=0.70 (0.49 to 0.84), negative predictive value=0.44 (0.23 to 0.67).
  
  
  CONCLUSIONS
  As a diagnostic tool for DCI, qualitative assessment of CTP is overall superior to NCT and CTA and could be useful for fast decision-making and guiding treatment.
authors.affiliation: Department of Radiology, Rudolf Magnus Institute for Neuroscience, University Medical Center, Utrecht, The Netherlands. j.w.dankbaar@umcutrecht.nl
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Dankbaar
authors.forename: Nicolien K
authors.initials: NK
authors.lastname: de Rooij
authors.forename: Birgitta K
authors.initials: BK
authors.lastname: Velthuis
authors.forename: Catharina J M
authors.initials: CJ
authors.lastname: Frijns
authors.forename: Gabriel J E
authors.initials: GJ
authors.lastname: Rinkel
authors.forename: Irene C
authors.initials: IC
authors.lastname: van der Schaaf
mesh_terms: D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*