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VascularIntermediate 30–45 min

Lower Extremity Venous Duplex (DVT)

Indication: Leg swelling/pain; elevated D-dimer; cancer surveillance; DVT risk

How to Perform

  1. 1

    Patient supine with leg slightly externally rotated. Use linear probe (5–12 MHz).

  2. 2

    Start at CFV in the groin: transverse view, compress fully — walls should touch. Scan proximally to SFJ.

  3. 3

    Sweep distally in transverse with compression every 1–2 cm through the femoral vein in the thigh.

  4. 4

    At the popliteal fossa (patient prone or knee bent): compress popliteal vein transversely from distal thigh to trifurcation.

  5. 5

    Add color Doppler and augmentation (calf squeeze releases): normal response is flow augmentation. Loss = proximal obstruction.

  6. 6

    Assess phasicity: normal venous flow waxes/wanes with respiration. Continuous non-phasic flow = proximal obstruction.

  7. 7

    Document each segment: compressible (normal), non-compressible (DVT), echogenic thrombus characteristics.

Measurement Guide

Common Femoral Vein (CFV) Diameter

Where:Transverse view at the groin, at the level of the saphenofemoral junction. Measure lumen diameter before compression.
Normal:Variable; non-compressibility is more important than diameter alone
Tip:Compress fully — normal vein walls fully touch (compressible = no DVT). Do not rely on diameter alone.

Popliteal Vein Diameter

Where:Posterior popliteal fossa, transverse view, with the knee slightly flexed. Inner wall to inner wall.
Normal:Variable; non-compressibility is diagnostic of DVT
Tip:Patient prone or knee flexed. Apply compression — walls should fully touch. Measure at mid-popliteal fossa.

Views to Obtain

  • Common femoral vein (CFV) — compression + Doppler
  • Femoral vein — mid/distal thigh compression
  • Popliteal vein — compression + Doppler
  • Trifurcation (peroneal, posterior tibial, anterior tibial)
  • GSV at saphenofemoral junction
  • Augmentation maneuvers (calf squeeze)

What to Look For

  • Vein compressibility
  • Intraluminal echogenic material
  • Augmentation response
  • Spontaneous flow pattern
  • Phasicity with respiration

Common Mistakes

  • Duplicate femoral veins — interrogate both
  • Calf DVT limited sensitivity without Doppler augmentation
  • Chronic DVT: thickened, echogenic wall ≠ acute thrombus

Pro Tip

Normal vein fully compresses (walls touch). Non-compressibility = DVT. Compare Doppler phasicity: loss = proximal obstruction.

AI Detects

Acute DVT (non-compressible)Chronic DVT (wall thickening)Partial thrombosisAbsent augmentation (proximal obstruction)
Start Scan — LE Venous Duplex

Protocol pre-selected · AI will use this context for analysis