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Images in Neurology
June 2008

The “OK” Sign: An Unusual Angiographic Appearance of Basilar Artery Fenestration

Arch Neurol. 2008;65(6):836. doi:10.1001/archneur.65.6.836

A 22-year-old woman with a history of headaches underwent brain imaging to exclude structural causes of headache. After magnetic resonance angiography suggested a basilar artery aneurysm, she was referred to our institution for further diagnostic workup. A conventional angiogram was performed and showed a possible aneurysm of the midbasilar segment (Figure A, arrow). Three-dimensional reconstructed images, however, demonstrated that this abnormality was clearly a fenestrated basilar artery without aneurysm. The image simulated an “ok” hand sign (Figure B, arrow) and no further intervention was taken.

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