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Abstract

For the past decades, new technical develop−
ments in brain imaging have greatly contributed to a better understanding of the pathophysiology of acute stroke und have paved the way for new possibilities in the diagnosis and treatment of acute stroke. Brain imaging provides indispensable information for a specific and effective management of acute stroke patients. Non−contrast CT is the most widely available technique and has its major impact in the diagnosis or exclusion
of intracranial hemorrhage. In addition, early
ischaemic signs can be identified on CT in a large number of patients already within the first hours of stroke. Non−contrast CT is the only imaging modality that is required prior to treatment with intravenous thrombolysis. Multiparametric stroke MRI including diffusion−weighted imaging, perfusion imaging, MR angiography and T2*−weighted imaging also detects intracranial haemorrhage with high sensitivity, and provides additional information on the extent of the ischaemic lesion, hypoperfused tissue and on the vessel status. Stroke MRI allows the identification of tissue at risk of infarction, which is the target for reperfusion therapies beyond the 3−hour time window. Multiparametric CT combining perfusion CT and CT angiography likely provides comparable information. Doppler and
duplex sonography is a reliable method to screen for pathologies of the extracranial arteries. Transcranial sonography additionally enables one to assess large intracranial vessels in the majority of patients. For the future, multiparametric brain imaging with modern CT or MRI techniques is expected to play an increasing role in the management of acute stroke in the routine clinical setting, as well as in clinical trials.