title: CT perfusion for detection of delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Delayed cerebral ischemia is a significant cause of morbidity and mortality after aneurysmal SAH, leading to poor outcomes. The purpose of this study was to evaluate the usefulness of CTP in determining delayed cerebral ischemia in patients with aneurysmal SAH.
  
  
  METHODS
  We conducted a systematic review evaluating studies that assessed CTP in patients with aneurysmal SAH for determining delayed cerebral ischemia. Studies using any of the following definitions of delayed cerebral ischemia were included in the systematic review: 1) new onset of clinical deterioration, 2) cerebral infarction identified on follow-up CT or MR imaging, and 3) functional disability. A random-effects meta-analysis was performed assessing the strength of association between a positive CTP result and delayed cerebral ischemia.
  
  
  RESULTS
  The systematic review identified 218 studies that met our screening criteria, of which 6 cohort studies met the inclusion criteria. These studies encompassed a total of 345 patients, with 155 (45%) of 345 patients classified as having delayed cerebral ischemia and 190 (55%) of 345 patients as not having delayed cerebral ischemia. Admission disease severity was comparable across all groups. Four cohort studies reported CTP test characteristics amenable to the meta-analysis. The weighted averages and ranges of the pooled sensitivity and specificity of CTP in the determination of delayed cerebral ischemia were 0.84 (0.7-0.95) and 0.77 (0.66-0.82), respectively. The pooled odds ratio of 23.14 (95% CI, 5.87-91.19) indicates that patients with aneurysmal SAH with positive CTP test results were approximately 23 times more likely to experience delayed cerebral ischemia compared with patients with negative CTP test results.
  
  
  CONCLUSIONS
  Perfusion deficits on CTP are a significant finding in determining delayed cerebral ischemia in aneurysmal SAH. This may be helpful in identifying patients with delayed cerebral ischemia before development of infarction and neurologic deficits.
authors.affiliation: From the Departments of Radiology (D.I.A.M., A.G., L.P., C.L.R., P.C.S.).
authors.forename: D I A
authors.initials: DI
authors.lastname: Mir
authors.affiliation: From the Departments of Radiology (D.I.A.M., A.G., L.P., C.L.R., P.C.S.).
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Public Health (A.D., P.C.S.).
authors.forename: A
authors.initials: A
authors.lastname: Dunning
authors.affiliation: From the Departments of Radiology (D.I.A.M., A.G., L.P., C.L.R., P.C.S.).
authors.forename: L
authors.initials: L
authors.lastname: Puchi
authors.affiliation: From the Departments of Radiology (D.I.A.M., A.G., L.P., C.L.R., P.C.S.).
authors.forename: C L
authors.initials: CL
authors.lastname: Robinson
authors.affiliation: the Samuel J. Wood Library and C.V. Starr Biomedical Information Center (H.-A.B.E.), Weill Cornell Medical College, New York, NY.
authors.forename: H-A B
authors.initials: HA
authors.lastname: Epstein
authors.affiliation: From the Departments of Radiology (D.I.A.M., A.G., L.P., C.L.R., P.C.S.)Public Health (A.D., P.C.S.) pcs9001@med.cornell.edu.
authors.forename: P C
authors.initials: PC
authors.lastname: Sanelli
mesh_terms: D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015984:Causality; D002533:Cerebral Angiography / Q000706:statistics & numerical data*; D015897:Comorbidity; D057210:Delayed Diagnosis / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D038622:Internationality; D008297:Male; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*