In this issue the paper by Chowdhury et al (see page 1416)¹ is an important addition to the list of recent publications that challenge traditional concepts on the mechanisms of acute ischaemic stroke. According to conventional teaching, an acute ischaemic stroke is characterised by infarction confined to a single localised (focal) region of the brain. However, new neuroimaging techniques—in particular diffusion weighted magnetic resonance imaging (dw-MRI)—have modified this view.

In a recent study,² scattered lesions in one vascular territory or multiple lesions in multiple vascular territories were actually more common than single …