Infarction: focal hypodense area, in cortical, subcortical, or deep gray or white matter, following vascular territory, or watershed distribution. Early subtle findings include obscuration of gray/white matter contrast and effacement of sulci, or "insular ribbon."

Hemorrhage: hyperdense image in white or deep gray matter, with or without involvement of cortical surface (40 to 90 HU). Petechial refers to scattered hyperdense points, coalescing to form irregularly hyperdense areas with hypodense interruptions. Hematoma refers to a solid, homogeneously hyperdense image.

Hyperdense image in major intracranial artery: suggestive of vascular embolic material.

Calcification: hyperdense image within or attached to vessel wall (>120 HU).

Incidental: silent infarct, subdural collection, tumor, giant aneurysm, arteriovenous malformation.

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References:

1. Culebras A, Kase CS, Masdeu JC, Fox AJ, Bryan RN, Grossman CB, Lee DH, Adams HP, Thies W. Practice guidelines for the use of imaging in transient ischemic attacks and acute stroke. A report of the Stroke Council, American Heart Association. Stroke. 1997 Jul;28(7):1480-97. [Medline]

Created: April 19, 2005