Learning Radiology xray montage

Dense Middle Cerebral Artery (MCA) Sign

General Considerations

  • Appearance of increased attenuation of the middle cerebral artery (MCA) on an unenhanced CT of the brain
  • Early sign (within 90 minutes) of ischemic stroke
  • Due to thrombosis of proximal MCA (M1 segment), but also seen in the posterior cerebral artery, vertebral artery and basilar artery
  • May be the only diagnostic feature of early stroke on CT
    • Most have an absolute density of >43 HU
  • But also may be associated with insular ribbon sign

Clinical Findings

  • Initial neurological deficit is more severe in patients with dense MCAs than in those lacking this sign Imaging

 Hyperdense Middle Cerebral Artery Sign (Dense MCA Sign)

 Hyperdense Middle Cerebral Artery Sign (Dense MCA Sign). Unenhanced axial CT of the brain show the right middle cerebral artery (white arrows) is hyperdense. The patient was showing the signs and symptoms of a stroke.


What constitutes a true hyperdense middle cerebral artery sign? CK Koo, E Teasdale E, and KW Muir. Cerebrovasc Dis. 2000 Nov-Dec;10(6):419-23.