magnetic resonance imaging in the investigation of stroke
Last reviewed 01/2018
MRI is used less routinely than CT for investigation in neurology primarily because of its higher cost and lower availability. Ischaemia is seen as hypointensity in relation to white and grey matter - TI prolongation.
An important advantage over CT is its ability to image clearly the posterior fossa and its structures; hence, posterior circulation strokes are more readily identified.
Additionally, it can detect ischaemic changes within 45 minutes of their onset. However, these very early changes are not very specific and there may be difficulty in distinguishing between haemorrhage and ischaemia.
MRI is more reliable in detecting sagittal sinus thrombosis and small cavernous haemangiomas.