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Findings: Axial CT images of the brain were performed. The first image demonstrates increased density throughout the left middle cerebral artery. The second image taken approximately 13 hours later demonstrates an evolving large infarct involving the left middle cerebral artery vascular territory.
Diagnosis: Hyperdense MCA sign.
Discussion: A hyperdense MCA sign can be seen with acute thrombus formation. A hyperdense MCA sign is indicative of an impending large infarct and is of very poor prognosis. This is a very early CT finding of impending infarction. It should be noted, however, that there are other causes of a hyperdense MCA such as atherosclerotic calcifications.
Other early findings in an acute stroke include loss of the insular ribbon as well as hypodensity within the lentiform nucleus. Loss of the gray/white junction is also an early finding in acute infarction.
The region of infarction can be more accurately located by magnetic resonance imaging. Such findings include absence of the normal "flow void" as well as edema with loss of the gray/white junction.
References:
Osborn AG. Diagnostic Neuroradiology. St. Louis, Mosby 1994;344-349.
Tomsick T, Brott T, Barsan W, et al. Thrombus Localization with Emergency
Cerebral CT, American Journal of Neuroradiology. 1992;13:257-263.
Truwit CL, Barkovich AJ, Jean A, et al. Loss of the Insular Ribbon: Another
CT Sign of Acute Middle Cerebral Artery Infarction. Radiology 1990;176:801-806.
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