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Left vertebral artery

The left vertebral artery (LVA) is a major branch of the left subclavian artery that ascends through the transverse foramina of the cervical vertebrae to supply blood to the posterior circulation of the brain, including the medulla, cerebellum, and posterior cerebral hemispheres. It is one of the two vertebral arteries that converge to form the basilar artery at the pontomedullary junction.

The artery is divided into four segments:

  • V1 (pre-foraminal): Originates from the subclavian artery to the C6 transverse foramen

  • V2 (foraminal): Ascends within the transverse foramina of C6 to C2

  • V3 (atlantic or extradural): Loops around the atlas (C1) and passes posterior to the lateral mass

  • V4 (intradural): Pierces the dura and enters the posterior cranial fossa, joining the basilar artery

The LVA is crucial for posterior cerebral perfusion, and its pathology can lead to vertebrobasilar insufficiency, strokes, or aneurysms. It is a key structure for radiologists, neurosurgeons, and interventionalists during imaging, endovascular procedures, and cervical spine surgery.

Function

  • Supplies posterior brain structures, including brainstem, cerebellum, and occipital lobes

  • Contributes to the vertebrobasilar circulation

  • Provides collateral circulation in cases of internal carotid artery compromise

Synonyms

  • Left VA

  • Left vertebrobasilar artery

  • Left cervical vertebral artery

MRI Appearance

T1-weighted images:

  • The artery appears as a small tubular structure of intermediate signal intensity, best visualized in high-resolution MR angiography

  • Flow voids are typically seen as signal loss in conventional T1 sequences, especially in V2–V4 segments

  • Vessel wall pathology, like dissection or mural hematoma, may appear as eccentric high signal within the wall

T2-weighted images:

  • Normal vertebral artery lumen may appear as a flow void (hypointense)

  • Surrounding cerebrospinal fluid (CSF) provides hyperintense contrast

  • Vessel wall irregularities or thrombus may appear hyperintense within the lumen

STIR (Short Tau Inversion Recovery):

  • Used primarily to highlight perivascular edema or inflammation

  • Normal artery remains signal void; pathological changes (vasculitis, dissection) appear hyperintense

T1 Post-Contrast (Gadolinium-enhanced):

  • Lumen enhances brightly in contrast-enhanced MRA sequences

  • Wall enhancement indicates dissection, vasculitis, or intramural thrombus

  • Excellent for assessing aneurysms or stenosis

CT Appearance:

  • On CT angiography, the artery appears as a contrast-filled tubular structure ascending through the transverse foramina

  • Bone landmarks (C1–C6 transverse processes) help trace the course of the artery

  • Pathologies such as stenosis, dissection, thrombus, or aneurysm are easily identified

  • Non-contrast CT may demonstrate calcified plaques along the vessel wall

MRI images

left vertebral artery mri coronal image -img-00000-00000

MRI images

Left vertebral artery mri axial image

MRI images

MRI Left vertebral artery axial anatomy image -img-00000-00000

MRI images

MRI Left vertebral artery coronal anatomy image -img-00000-00000