Echoplanar magnetic resonance imaging in acute stroke

Echoplanar magnetic resonance imaging (EPI) enables rapid, non-invasive ima ging and analysis of cerebral pathophysiology in acute stroke. It represent s an important clinical advance over computed tomography (CT) and conventio nal magnetic resonance (MR) scanning. It can rapidly delineate infarcted ce rebral tissue and distinguish acute from chronic stroke. In addition, EPI h as the potential to quickly determine the presence and degree of potentiall y viable brain tissue in the ischaemic penumbra. Thrombolysis is thought to reperfuse the penumbra and hence reduce infarct size. The thrombolytic age nt tissue plasminogen activator (t-PA) improves outcome in ischaemic stroke when administered within the first 3 hours of onset. However, there is a s ignificant risk of haemorrhage, and the time window for benefit may well ex ceed 3 hours in some patients. Hence, by facilitating diagnosis of 'at-risk ' tissue in the ischaemic penumbra, a major clinical role of EPI may well b ecome the rational selection of patients for acute interventional stroke th erapy. (C) 2000 Harcourt Publishers Ltd.