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Title
Selection of thrombolytic therapy beyond 3 h using magnetic resonance imaging
Author/Creator
Davis, S. M.;  Donnan, G. A.;  Butcher, K. S.;  Parsons, Mark
Description
Purpose of review Use of intravenous thrombolytic therapy in ischaemic stroke is restricted to a 3-h time window because of the proof of this time window in pivotal clinical trials. Thrombolysis is aimed at recanalization of occluded arteries and reperfusion of the ischaemic penumbra, a region of critically hypoperfused, functionally impaired, but potentially viable brain. There are a number of current prospective trials that are testing the hypothesis that the presence of the penumbra will predict thrombolytic responders beyond 3 h. Recent findings Using magnetic resonance imaging, a mismatch between a larger perfusion-weighted imaging lesion and smaller diffusion-weighted imaging lesion is considered to represent the ischaemic penumbra. Perfusion-weighted imaging provides semiquantitative cerebral blood flow imaging and diffusion-weighted imaging is an index of the largely irreversible ischaemic core. This definition has been modified with the recognition that the perfusion-weighted imaging lesion includes benign oligaemia and that a portion of the diffusion-weighted imaging core is potentially salvageable with rapid reperfusion. Most acute stroke patients have a magnetic resonance imaging-penumbral signature within 6 h of stroke onset. The penumbra is commonly, but not invariably, associated with proximal arterial occlusion and is time-dependent. Preliminary studies have shown benefit from thrombolytic therapy beyond the established 3-h window. Summary Penumbral imaging using magnetic resonance imaging with perfusion over diffusion weighted imaging mismatch can provide a physiological 'tissue clock' in individual patients. Based on this hypothesis, a number of prospective trials are being performed. These include EPITHET, DEFUSE, DIAS, MR RESCUE and ROSIE.
Relation
Current Opinion in Neurology Vol. 18, no. 1, p. 47-52
Date
2005
Publisher
Rapid Science Publishers
Keyword(s)
ischaemic stroke;  magnetic resonance imaging;  mismatch;  penumbra;  stroke outcome;  tissue-plasminogen activator;  perfusion-weighted mri;  acute;  ischemic-stroke;  cerebral blood-flow;  thresholds;  predicts;  tomography;  volumes;  trials
Resource Type
journal article
Rights
*
Identifier
http://hdl.handle.net/1959.13/25183
Identifier
ISSN:1535-3850
Language
eng
Reviewed
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Subject
"Current Opinion in Neurology"
 
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