FLAIR vascular hyperintensities

Last revised by Khalid Alhusseiny on 8 Jan 2023

FLAIR vascular hyperintensities are hyperintensities encountered on FLAIR sequences within subarachnoid arteries related to impaired vascular hemodynamics 1,2. They are usually seen in the setting of acute ischemic stroke and represent slow retrograde flow through collaterals (and not thrombus) distal to the site of occlusion 3.

Although more studies are needed to confirm their significance and this is somewhat controversial at the time of writing this article, they are mostly thought to represent good collaterals and be associated with a better prognosis in the setting acute ischemic stroke 4-7.

Radiographic features

MRI
  • FLAIR: serpiginous/linear hyperintense signal within an artery in the subarachnoid space

See also

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