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Accessory saphenous vein

The accessory saphenous vein (ASV) is a superficial tributary of the great saphenous vein (GSV). It usually runs along the anteromedial or posteromedial thigh and drains into the GSV near the saphenofemoral junction (SFJ). Variants include the anterior accessory saphenous vein (AASV) and posterior accessory saphenous vein (PASV).

The ASV is clinically significant as a frequent site of venous reflux contributing to varicose veins. Recognition of its anatomy and course is essential in endovenous ablation, ligation, and venous mapping.

Synonyms

  • Anterior accessory saphenous vein (AASV)

  • Posterior accessory saphenous vein (PASV)

  • Tributary of GSV

Function

  • Drains the anteromedial and posteromedial thigh

  • Provides collateral venous return into the great saphenous vein

  • Clinically important in venous reflux, thrombophlebitis, and varicose vein recurrence

MRI Appearance

T1-weighted images:

  • Vein: hypointense tubular lumen

  • Surrounded by hyperintense subcutaneous fat for contrast

T2-weighted images:

  • Flowing blood: signal void

  • Thrombosis: lumen appears hyperintense or heterogeneous

STIR:

  • Suppresses fat, enhancing vein conspicuity

  • Thrombophlebitis: perivenous edema appears bright

T1 Fat-Suppressed Post-Gadolinium:

  • Vein enhances brightly, especially at junction with GSV

  • Highlights varicose tributaries and neovascularization

MRV (Magnetic Resonance Venography):

  • Signal: flowing blood appears bright hyperintense on contrast-enhanced MRV

  • Thrombosed vein: hypointense or non-enhancing lumen

  • Depicts ASV trajectory, size, junction with GSV, and reflux when present

  • Excellent for venous mapping in varicose vein surgery

CT Appearance

Non-contrast CT:

  • Vein usually not visible

  • Appears as faint tubular soft-tissue density in subcutaneous tissue

CT Post-Contrast:

  • Enhances clearly along medial thigh

  • Useful for identifying dilated tributaries, thrombosis, or venous anomalies

CTV (CT Venography):

  • Signal: enhanced lumen appears bright hyperdense relative to surrounding soft tissue

  • Thrombosis: seen as filling defect within enhancing vein

  • Provides 2D and 3D reconstructions of ASV, its junction with GSV, and relation to SFJ

  • Excellent for planning endovenous interventions

CT VRT 3D image

Accessory Saphenous Vein 3D

CT image

Accessory Saphenous Vein CT axial anatomy image-img-00000-00000

MRI image

Accessory Saphenous Vein MRI axial anatomy image-img-00000-00000