Published online before print October 13, 2005, doi: 10.1161/01.STR.0000185933.44619.1b
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(Stroke. 2005;36:2333.)
© 2005 American Heart Association, Inc.
Editorials |
Imaging the Clot
Does Clot Appearance Predict the Efficacy of Thrombolysis?
From the Unitat Neurovascular, Hospital Vall d’Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain.
Correspondence to Carlos A. Molina, MD, PhD, Unitat Neurovascular, Hospital Vall d’Hebron. Universitat Autonoma de Barcelona, Passeig vall d’Hebron 119-129, 08035 Barcelona, Spain. E-mail cmolina@vhebron.net
Key Words: brain imaging • reprefusion • stroke
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
See related article, pages 2379–2383.
Unlike in acute myocardial infarction, the underlying pathophysiological mechanism of vascular arterial occlusion in acute stroke is heterogeneous. Composition of cerebral embolic material may vary, depending on specific endothelial and flow conditions of the embolic source. Old, platelet-rich, and well-organized thrombi formed under flow conditions have been shown to be more resistant to thrombolysis than fresh, fibrin- and red cell–rich clots formed under conditions of stasis.1 Moreover, clot structure may differ depending on whether the embolic source is a thrombus engrafted in a proximal atherosclerotic lesion or a clot formed in cardiac cavities. In this context, stroke subtypes may represent a surrogate of the composition of offending clot.
Efforts to image intravascular thrombus in acute ischemic stroke have been increasingly done in the last years. In acute ischemic stroke, the presence of hyperattenuated middle cerebral artery sign on computed tomography indicates intraluminal clot with a high specificity but low sensitivity (47%).2 On MRI, vessel signs of arterial occlusion have been described as hyperintense vessel sign on fluid-attenuated inversion recovery images and as susceptibility vessel sign on gradient-echo (GRE SVS) images.3,4 The basis for the detection of GRE SVS in patients with an acute intracranial artery occlusion is paramagnetic deoxyhemoglobin causing signal loss. In patients with acute ischemic stroke imaged at <6 hours of stroke onset, GRE SVS has been shown to have a high sensitivity for detecting an acute intracranial occlusion compared with vessel status on magnetic resonance (MR) angiography.3 Sensitivity and specificity of
Related Article:
Stroke 2005 36: 2379-2383.