What is the best imaging strategy for acute stroke?

Wardlaw JM, Keir SL, Seymour J, Lewis S, Sandercock PAG, Dennis MS, et al
Record ID 32004000091
English
Authors' objectives:

- To determine the cost-effectiveness of computed tomographic (CT) scanning after acute stroke. - To assess the contribution of brain imaging to the diagnosis and management of stroke. - To estimate the costs, benefits and risks of different imaging strategies. - To provide data to inform national and local policy on the use of brain imaging in stroke.

Authors' results and conclusions: Clinicians disagree on the clinical diagnosis of stroke (versus not stroke) in about 20% of patients. It is impossible to differentiate infarct from haemorrhage by clinical examination. CT is very sensitive and specific for haemorrhage within the first 8 days of stroke only. Suboptimal scanning used in epidemiology studies suggests that the frequency of primary intracerebral haemorrhage (PICH) has been underestimated. Aspirin increases the risk of PICH. There was no evidence that a few doses of aspirin given inadvertently to patients with acute PICH significantly increased the odds of death [odds ratio (OR) 0.96, 95% confidence interval (CI) 0.62 to 1.5] or recurrent intracranial haemorrhage (OR 1.02, 95% CI 0.5 to 1.8), so long as only a few doses were given. There were no reliable data on functional outcome or on the effect of antithrombotic treatment given long term after PICH. In 60% of patients with recurrent stroke after PICH, the cause is another PICH and mortality is high among PICH patients. Among 232 patients (mainly outpatients) with mild stroke, 3% had a PICH and 15% had haemorrhagic transformation of an infarct. CT did not reliably detect PICH after 8 days. A specific MR sequence (gradient echo) is required to identify prior PICH reliably.
Authors' recomendations: In general, strategies in which most patients were scanned immediately cost least and achieved the most QALYs, as the cost of providing CT (even out of hours) was less than the cost of inpatient care. Increasing independent survival by even a small proportion through early use of aspirin in the majority with ischaemic stroke, avoiding aspirin in those with haemorrhagic stroke, and appropriate early management of those who have not had a stroke, reduced costs and increased QALYs. Sensitivity analyses to vary the cost of scanning, different age ranges, proportions of infarcts, haemorrhages or tumours/infections, accuracy of CT, utility weights, and length of stay assumptions did not alter the ranking of strategies. However, although, the model was sensitive to reducing the cost of inpatient care, scan all immediately remained the dominant strategy.
Authors' methods: Decision-analysis model
Details
Project Status: Completed
URL for project: http://www.hta.ac.uk/1073
Year Published: 2004
English language abstract: An English language summary is available
Publication Type: Not Assigned
Country: England, United Kingdom
MeSH Terms
  • Costs and Cost Analysis
  • Diagnostic Imaging
  • Stroke
Contact
Organisation Name: NIHR Health Technology Assessment programme
Contact Address: NIHR Journals Library, National Institute for Health and Care Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK
Contact Name: journals.library@nihr.ac.uk
Contact Email: journals.library@nihr.ac.uk
Copyright: 2009 Queen's Printer and Controller of HMSO
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