Fenestration of the extracranial vertebral artery - Possible misinterpretation as vertebral artery dissection

Fenestration of the vertebral artery is a rare congenital variation which is usually of no clinical significance. However, ultrasonographic findings of fenestration may cause misinterpretation as arterial dissection mimicking a "double-lumen sign". We report a case of vertebral artery fenestration in the lower cervical segment (C6 - C4) and demonstrate typical Doppler criteria in order to differentiate between fenestration and dissection.