Topics

Topic

design image
Left subclavian artery

The left subclavian artery is a major artery arising from the aortic arch, supplying blood to the left upper limb, neck, thoracic wall, and portions of the brain. Its anatomical course, clinical significance, and imaging appearance are critical in vascular, neuro, and thoracic radiology. Understanding its features aids in the evaluation of vascular diseases, trauma, and planning for interventions.

Synonyms

  • Subclavia sinistra

  • Arteria subclavia sinistra

  • Left SCA (common abbreviation)

  • Left upper limb main artery (descriptive, less common)

Function

  • Supplies oxygenated blood to the left upper limb, shoulder, and parts of the neck.

  • Provides branches (vertebral, internal thoracic, thyrocervical trunk, costocervical trunk, dorsal scapular artery) important for cerebral, thoracic, and cervical perfusion.

  • Critical for collateral circulation in cases of proximal vascular obstruction.

MRI Appearance

  • T1-weighted:

    • Vessel lumen appears as a flow void (black), with the artery wall and perivascular fat as hyperintense.

  • T2-weighted:

    • The artery itself remains a flow void; surrounding edema or pathology appears hyperintense.

  • STIR (Short Tau Inversion Recovery):

    • Suppresses fat signal; artery still visualized as a flow void; enhances detection of perivascular edema or inflammation.

  • TOF (Time-of-Flight MRA):

    • Excellent for non-contrast visualization.

    • Flowing blood appears hyperintense (bright), delineating the artery clearly.

    • Useful for identifying stenosis, occlusion, or aneurysm without intravenous contrast.

CT Appearance

  • Non-contrast CT:

    • Appears as a soft tissue structure, difficult to distinguish from surrounding tissues.

    • Lumen not well visualized unless calcified atherosclerotic plaque is present.

  • CT Angiography (CTA):

    • Artery opacifies brightly following contrast administration.

MRI images

Left subclavian artery MRI CORONAL IMAGE