title: Effectiveness of diagnostic strategies in suspected delayed cerebral ischemia: a decision analysis.
abstract: OBJECTIVE
  Delayed cerebral ischemia (DCI) is a serious complication after aneurysmal subarachnoid hemorrhage. If DCI is suspected clinically, imaging methods designed to detect angiographic vasospasm or regional hypoperfusion are often used before instituting therapy. Uncertainty in the strength of the relationship between imaged vasospasm or perfusion deficits and DCI-related outcomes raises the question of whether imaging to select patients for therapy improves outcomes in clinical DCI.
  
  
  METHODS
  Decision analysis was performed using Markov models. Strategies were either to treat all patients immediately or to first undergo diagnostic testing by digital subtraction angiography or computed tomography angiography to assess for angiographic vasospasm, or computed tomography perfusion to assess for perfusion deficits. According to current practice guidelines, treatment consisted of induced hypertension. Outcomes were survival in terms of life-years and quality-adjusted life-years.
  
  
  RESULTS
  When treatment was assumed to be ineffective in nonvasospasm patients, Treat All and digital subtraction angiography were equivalent strategies; when a moderate treatment effect was assumed in nonvasospasm patients, Treat All became the superior strategy. Treating all patients was also superior to selecting patients for treatment via computed tomography perfusion. One-way sensitivity analyses demonstrated that the models were robust; 2- and 3-way sensitivity analyses with variation of disease and treatment parameters reinforced dominance of the Treat All strategy.
  
  
  CONCLUSIONS
  Imaging studies to test for the presence of angiographic vasospasm or perfusion deficits in patients with clinical DCI do not seem helpful in selecting which patients should undergo treatment and may not improve outcomes. Future directions include validating these results in prospective cohort studies.
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.). sapna.rawal@uhn.ca.
authors.forename: Sapna
authors.initials: S
authors.lastname: Rawal
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.).
authors.forename: Carolina
authors.initials: C
authors.lastname: Barnett
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.).
authors.forename: Ava
authors.initials: A
authors.lastname: John-Baptiste
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.).
authors.forename: Hla-Hla
authors.initials: HH
authors.lastname: Thein
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.).
authors.forename: Timo
authors.initials: T
authors.lastname: Krings
authors.affiliation: From the Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada (S.R., T.K.); Division of Neurology, Department of Medicine, Toronto General Hospital, University of Toronto, Toronto, Canada (C.B.); Department of Anesthesia and Perioperative Medicine, Schulich School of Medicine and Dentistry, Western University, London, Canada (A.J.-B.); Women's College Research Institute, Women's College Hospital, University of Toronto, Toronto, Canada (A.J.-B.); Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada (H.-H.T.); Ontario Institute for Cancer Research, Toronto, Canada (H.-H.T.); Institute for Clinical Evaluative Sciences, Toronto, Canada (H.-H.T.); and Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center, Utrecht, The Netherlands (G.J.E.R.).
authors.forename: Gabriel J E
authors.initials: GJ
authors.lastname: Rinkel
mesh_terms: D017542:Aneurysm, Ruptured / Q000150:complications*; D015901:Angiography, Digital Subtraction; D001921:Brain / Q000000981:diagnostic imaging*; D002545:Brain Ischemia / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D002533:Cerebral Angiography; D002544:Cerebral Infarction / Q000209:etiology / Q000517:prevention & control; D003661:Decision Support Techniques; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications*; D008390:Markov Chains; D008875:Middle Aged; D055420:Perfusion Imaging; D019057:Quality-Adjusted Life Years; D012422:Rupture, Spontaneous; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D020301:Vasospasm, Intracranial / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology
keywords: angiography; brain ischemia; decision support techniques; diagnostic imaging; perfusion imaging; subarachnoid hemorrhage; vasospasm, intracranial