Non-Contrast CT: MCA Sign/Loss of insular ribbon

The hyperdense MCA sign refers to the appearance of the middle cerebral artery (MCA) on CT. It has been associated with poor outcome.

There is increased attenuation of the proximal portion of the MCA and it is often associated with thrombosis of the M1 MCA segment. It is one of the early signs of an MCA infarct [10].

The sign is typically seen within 90 minutes of the ischaemic event, and thus, it is very important to recognise this sign. This sign has approx. 100% sensitivity, however only 30% specificity.

It is usually associated with another important sign of acute ischaemia: insular ribbon sign. This is a loss of definition of the grey-white interface in the lateral margin of the insular cortex (“insular ribbon”).