It is increasingly recognised that both stroke and transient ischaemic attacks (TIA) are medical emergencies and that rapid clinical and radiological evaluation underpin the urgent management of cerebrovascular disease. The arbitrary duration based separation of stroke from TIA is felt by many to be redundant in the era of stroke treatment, and the term acute ischaemic cerebrovascular syndromes (AICS) is a suggested alternative analogous to cardiological terminology changes. However, presentation with an acute stroke syndrome diagnosed clinically is not synonymous with an AICS, since there are a number of pathologies that can produce identical clinical pictures, and many stroke mimics. Imaging is an essential component of diagnosis.

The need for increasingly early imaging has led to new emphasis on hyperacute changes on plain computed tomography (CT) and has also seen the widespread use of more complex imaging modalities in acute stroke.

Immediate brain imaging with CT for all stroke patients on admission is more cost effective than deferred imaging, even when the possible interventions are limited to aspirin use and stroke unit care. A cost effectiveness analysis has not yet been done to take into account thrombolytic treatment or modalities other than routine CT.

ACUTE STROKE

Around 85% of cases of stroke fulfilling the 1976 World Health Organization definition are ischaemic in origin, with 10% caused by focal haemorrhage and 5% by subarachnoid haemorrhage (SAH). Since SAH rarely presents with sudden focal symptoms, this review will ignore SAH.

Many ischaemic strokes exhibit rapid early improvement, leading clinicians to apply the term “TIA” when strictly speaking this label is attached only when symptoms resolve entirely within 24 hours. Most true TIAs last minutes, and the longer the symptoms last, the greater the likelihood of a causative lesion being identified on imaging.

Haemorrhage

Computed tomography

Non-contrast CT (NCCT) remains the gold standard means of detecting intracranial haemorrhage …