Hyperdense MCA sign (brain)
The hyperdense MCA sign refers to focal increased density of the middle cerebral artery on CT and is direct visualisation of thromboembolic material within the lumen. It is thus the earliest visible sign of MCA infarction seen immediately at the time of embolism. It is the longitudinal equivalent of the MCA dot sign and hyperdense basilar tip sign.
The hyperdensity of the arterial content is due to the thrombus having previously formed and contracted, usually within the heart or carotid bulb, prior to embolizing and occluding the MCA.
The proximal portion of the MCA, often extending into the terminal supraclinoid internal carotid artery, is hyperdense compared to the other side and to the basilar tip which is often at a similar level.
Care must be taken not to over call this sign on thick axial slices only as different slice position relative to the MCA can lead to asymmetry. Review of thin-section CT and multiplanar reformats is usually able to confirm it as a true finding.
Treatment and prognosis
Hyperdense MCA sign has been associated with poor outcome, although this is by no means established, especially in light of recent endovascular clot retrieval techniques.
Usually, there is no differential diagnosis, as the clinical context is consistent with ipsilateral middle cerebral artery occlusion.
Occasionally, a similar appearance may be the result of calcified atherosclerotic disease. High haematocrit can lead to elevated intravascular density, however, this is present throughout all visualised vessels.
There are occasional reports of a hyperdense MCA sign seen with HSV encephalitis 4.
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Stroke and intracranial haemorrhage
stroke and intracranial haemorrhage
- general discussions
- scoring and classification systems
- by region
- hemispheric infarcts
- frontal lobe infarct
- parietal lobe infarct
- temporal lobe infarct
- occipital lobe infarct
- internal capsule infarct
- ataxic hemiparesis syndrome: MCA perforators or basilar artery perforators
- lacunar infarct
- thalamic infarct
- cerebellar infarct
- midbrain infarct
- pontine infarct
- medullary infarct
- acute spinal cord ischaemia syndrome
- hemispheric infarcts
- by vascular territory
- anterior cerebral artery infarct
- anterior choroidal artery infarct
- anterior inferior cerebellar artery infarct
- basilar artery infarct
- middle cerebral artery infarct
- posterior cerebral artery infarct
- posterior inferior cerebellar artery infarct
- superior cerebellar artery infarct
- basal ganglia haemorrhage
- cerebellar haemorrhage
- cerebral contusions
- CTA spot sign
- haemorrhagic venous infarct
- haemorrhagic transformation of an ischaemic infarct
- hypertensive intracranial haemorrhage
- intraventricular haemorrhage (IVH)
- lobar haemorrhage
- pontine haemorrhage
- remote cerebellar haemorrhage
- extra-axial haemorrhage
- extradural haemorrhage (EDH)
- intralaminar dural haemorrhage
- subdural haemorrhage (SDH)
- subarachnoid haemorrhage (SAH)
- intra-axial haemorrhage
- ischaemic stroke