A 58-year-old man presents with acute right-sided weakness of 3 hours duration. Non-contrast CT head shows a linear hyperdense vessel in the left sylvian fissure with attenuation greater than adjacent bone. This finding represents:

• A Contrast extravasation from prior angiography
• B Acute parenchymal haemorrhage
• C Calcified atherosclerotic plaque of the sylvian artery
• D Thrombus within the middle cerebral artery (dense MCA sign) ✓

Explanation

The hyperdense MCA sign is thrombus within the first segment of the middle cerebral artery, seen as a serpiginous hyperdensity in the sylvian fissure on non-contrast CT in early ischaemic stroke. Its specificity increases when attenuation exceeds that of adjacent cortical bone. Parenchymal haemorrhage appears as a rounded hyperdense clot within brain tissue, not a tubular vessel-shaped density.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.