Bilateral asymmetrical duplicated origin of vertebral arteries: Multidetector row CT angiographic study.

Bilateral duplicated origin of V-1 segment of vertebral arteries is an extremely rare vascular variant and only two such cases have been reported so far. Presence of this vascular abnormality was observed incidentally in a 36-year-old male patient, with a complaint of dizziness, evaluated by multidetector row computed tomography (CT) angiography. Two limbs of the right vertebral artery arose from the right subclavian artery and fused to form a single vessel at the interval between fourth and fifth cervical vertebrae, which entered the foramen transversarium of fourth cervical vertebra. On the left side, the medial limb originated directly from the arch of aorta and the lateral limb from the left subclavian artery, and both united at the interval between fifth and sixth cervical vertebrae to form a single vessel which entered the foramen transversarium of fifth cervical vertebra. No other cerebrovascular pathology like aneurysm, fenestration, dissection, and stenosis was detected, which could be correlated with the symptoms of the patient. This rare congenital vascular anomaly has diagnostic and therapeutic implications in any intervention involving the vertebral artery.