Fenestration of the vertebral artery at the lower cervical segment - Imaging findings and literature review

Fenestrations of the vertebral artery are mostly found at the upper cervical or intracranial segments. We present a rare case of vertebral artery fenestration at the lower cervical (C4-C6) segment, which showed a double-lumen appearance on ultrasonography. Computed tomographic angiography (CTA) and rotational angiography of the vertebral artery with three-dimensional (3D) reconstruction proved the diagnosis and nicely demonstrated the anatomic relationship between two limbs of the fenestrated artery. The embryonic mechanism and possible causes of rareness of this condition are discussed.