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Lower LimbDemonstration data

Lower-Limb Venous Doppler (DVT)

Compression ultrasound with colour and spectral Doppler is the primary imaging test for suspected lower-limb deep vein thrombosis. The single most reliable sign is loss of full compressibility of the vein under transducer pressure. Doppler augmentation and phasicity provide supportive haemodynamic information, particularly for the deep femoral and iliac segments that are difficult to compress.

Indications

  • Clinically suspected deep vein thrombosis (unilateral swelling, pain, tenderness)
  • Elevated D-dimer or intermediate/high Wells pre-test probability
  • Suspected recurrent DVT or extension of known thrombus
  • Pre-operative or high-risk screening in selected patients
  • Assessment of chronic venous changes and post-thrombotic syndrome

Contraindications & Cautions

  • No absolute contraindications; ultrasound is non-invasive and safe
  • Overlying wounds, casts or severe oedema may limit compression technique
  • Marked obesity or gas can obscure the iliac veins and calf
  • Do not apply firm compression directly over a suspected mobile fresh thrombus if avoidable

Patient Preparation

  • No fasting required
  • Supine with the leg externally rotated and knee slightly flexed
  • Reverse Trendelenburg (10-20 degrees) to distend the deep veins and pool blood
  • For popliteal and calf veins position prone or sitting with the leg dependent
  • Warm the limb to promote venous filling

Technique & Parameters

  • Linear 5-12 MHz probe for common femoral to popliteal veins; curvilinear 3-6 MHz for iliac veins or large limbs
  • Grey-scale transverse compression every 1-2 cm from the common femoral vein to the popliteal and calf veins
  • A patent vein walls fully coapt under gentle pressure; incomplete coaptation indicates thrombus
  • Colour Doppler to demonstrate luminal filling and identify non-occlusive filling defects
  • Spectral Doppler in the common femoral vein to assess spontaneous, phasic (respiratory-varying) flow
  • Distal augmentation (calf squeeze) to confirm patency and unmask non-occlusive proximal thrombus

Systematic Review

  • Common femoral vein: compressibility, spontaneous phasic flow and response to augmentation
  • Femoral (superficial femoral) and deep femoral veins along the thigh at short intervals
  • Popliteal vein and the tibioperoneal trunk
  • Calf veins (posterior tibial, peroneal, gastrocnemius/soleal) where clinically indicated
  • Great and small saphenous veins for superficial thrombophlebitis
  • Assess for extrinsic causes of swelling: Baker cyst, haematoma, mass

Key Findings & Significance

  • Acute DVT: non-compressible, distended vein with hypoechoic/anechoic intraluminal thrombus and absent colour filling
  • Non-occlusive thrombus: partial colour filling defect with a compressible residual lumen
  • Loss of respiratory phasicity or a continuous (non-phasic) common femoral waveform suggests proximal/iliac obstruction
  • Absent or blunted response to distal augmentation indicates intervening occlusion
  • Chronic thrombus: echogenic, retracted, wall-adherent thrombus with recanalisation and collaterals
  • Superficial thrombophlebitis: non-compressible echogenic superficial vein; note proximity to the saphenofemoral junction

Differential Considerations

  • Leg swelling/pain: acute DVT vs chronic post-thrombotic change vs cellulitis vs lymphoedema
  • Non-compressible vein: acute thrombus vs chronic wall-thickened vein vs technical (inadequate pressure)
  • Absent flow: occlusive thrombus vs vein spasm/low flow vs proximal obstruction
  • Extrinsic mass: ruptured Baker cyst, haematoma, abscess, tumour
  • Continuous CFV waveform: iliac/IVC thrombosis vs extrinsic pelvic compression vs pregnancy

Pearls & Pitfalls

  • Compressibility is the primary criterion; colour and spectral Doppler are supportive, not a substitute
  • A continuous, non-phasic or asymmetric common femoral waveform is an indirect clue to non-visualised iliac thrombus
  • Distinguish acute (soft, distended, hypoechoic) from chronic (echogenic, retracted, wall-adherent) thrombus to guide management
  • Isolated distal (calf) DVT may warrant follow-up rather than immediate anticoagulation per local protocol
  • Always look for an alternative cause of symptoms such as a Baker cyst or haematoma when veins are patent

Structured Report

  • State examined segments, probe and whether a complete or limited (2-point/proximal) protocol was used
  • Report compressibility, thrombus presence, extent, acuity and the most proximal and distal levels involved
  • Describe colour filling, phasicity and augmentation response
  • Note incidental findings (Baker cyst, superficial thrombophlebitis, mass)
  • Give an impression stating presence/absence, level and chronicity of DVT and recommend follow-up if limited

References

  • AIUM-ACR-SPR-SRU Practice Parameter for the Performance of Peripheral Venous Ultrasound Examination
  • Needleman L et al. Ultrasound for Lower Extremity DVT: SRU Consensus Conference. Circulation 2018
  • Hamper UM et al. Ultrasound Evaluation of the Lower Extremity Veins. Radiographics
  • ACCP/CHEST Guidelines on Antithrombotic Therapy for VTE Disease

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.