Non-Contrast CT

Non-contrast computed tomography (CT) is the most readily available imaging technique.

Non-contrast computed tomography (CT) is the most readily available imaging technique.

The main aim is to exclude a bleed as the cause of the focal neurological signs (rather than to see ischaemic changes). Early signs of ischaemia may or may not be seen, for example the loss of differentiation of the grey and white matter interface. CT may also show another cause, such as a brain tumour or subdural haemorrhage.

NICE Guidelines

The current NICE Pathway for acute stroke states that brain imaging should be performed immediately for people with acute stroke if any of the following apply:

• Indications for thrombolysis or early anticoagulation treatment;
• On anticoagulant treatment;
• A known bleeding tendency;
• A depressed level of consciousness (GCS <13);
• Unexplained progressive or fluctuating symptoms;
• Papilloedema, neck stiffness or fever;
• Severe headache at onset of stroke symptoms.

‘Immediately’ is defined as ‘ideally the next slot and definitely within 1 hour, whichever is sooner’ [9].

For all people with acute stroke without one of these indications for immediate brain imaging, scanning should be performed as soon as possible. ‘As soon as possible’ is defined as ‘within a maximum of 24 hours after onset of symptoms.