Normal Lower Limb and DVT Scanning Technique

The normal appearance of the lower limb veins are:-o Thin walled, easily compressible with transducer pressure, echolucent lumen

on B-mode.

Normal compressiblility of the Common Femoral Veinhttp://www.acep.org/uploadedImages/ACEP/Bookstore_and_Publications/ACEP_News/2009-

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o Colour Doppler demonstrates good colour filling with spectral augmentation for the distal thigh and calf veins.

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o Spectral Doppler demonstrates phasic response in the common femoral and femoral vein which decreases in the distal thigh.

Figure Six – Spectral trace of CFV demonstrating normal phasic responsehttps://lms.curtin.edu.au/bbcswebdav/pid-1033600-dt-content-rid-9183519_1/courses/310696-

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Deep vein thrombosis (DVT):Deep vein thrombosis (DVT) is a condition in which a blood clot forms in one of your deep veins, usually in your leg.

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Symptoms of DVT o swelling of the affected leg.o pain and tenderness in the affected leg. o localised redness and warmth of skin.o Homan’s Sign – pain in the calf with forced dorsiflexion of the foot.

Scanning Technique

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A detailed patient history must be taken prior to commencement of the examination

The limb(s) to be examined must be easily accessible from the groin to the ankle.

It is often necessary to extend the examination into the pelvis and lower abdomen.

If thrombosis extends past the inguinal ligament or there is loss of phasic/valsalva response in the common femoral vein indicating proximal disease the iliac veins must be examined and the proximal extent of the thrombus noted.

It is often difficult to compress the iliac veins, loss of colour filling and an absent spectral Doppler trace may demonstrate thrombus within the iliac veins.

The common femoral vein distends easily with the Valsalva manoeuvre.

The patient is most often supine with the head raised and the leg slightly externally rotated.

The common femoral vein is imaged in transverse section, in B-mode travelling down the thigh, compressing the vein every 1-2 cm to the profunda femoral and femoral veins.

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The femoral vein is now followed medially down the thigh towards the knee in B-mode using compression to the adductor canal.

The transducer maybe moved from a posterior position to a more anterior position to demonstrate the vein in the adductor canal and compression is often easier using your hand in the popliteal fossa/ posterior thigh.

The transducer is then moved back to the groin and using colour and spectral Doppler the common femoral vein, Greater saphenous vein junction, deep femoral vein (proximal portion only) and femoral vein are assessed for colour filling and normal spectral waveforms.

The common femoral vein shows a phasic response which diminishes distally in the thigh, the adductor canal occasionally requires distal calf augmentation to demonstrate colour and spectral Doppler flow.

The greater saphenous vein is examined using compression from the junction with the common femoral vein to the knee. Colour filling will help demonstrate patency but will not exclude thrombus.

If possible the table is raised and the patient sits on the edge of the table with their legs in a dependant position, usually resting their foot on the examiners knee. Other positions are prone with legs

raised on the table, decubitus with the side being examined uppermost or standing.

The popliteal vein is examined from the adductor canal to the proximal calf in transverse section using B-mode and compression until the posterior tibial and peroneal veins are seen.

The calf veins can either be imaged from a central position on the posterior calf allowing both paired posterior tibial and peroneal veins to be imaged, in transverse using compression to the ankle.

It is occasionally easier to image the posterior tibial veins adjacent to the tibia from the medial aspect of the calf and the peroneal veins adjacent to the fibula from a lateral/posterior position on the calf.

Colour and spectral Doppler are used to demonstrate colour filling and flow (using distal augmentation).

The medial and lateral gastrocnemius veins are examined using B-mode and compression, colour filling is occasionally helpful. The soleal veins (sinuses) are also examined with compression.

The small saphenous vein is compressed from the ankle to its junction with the popliteal vein or as it becomes the Giacomini vein into the distal posterior thigh.

A normal protocol for assessing the lower limb veins: Dual imaging one side normal other side demonstrating compression. B-mode Transverse section

Start at the inguinal canal and display;1. Common femoral vein2. Greater saphenous junction3. Femoral and profunda femoral vein4. Femoral vein proximal5. Femoral vein mid6. Femoral vein distal (adductor canal)

Colour and spectral Doppler images in longitudinal demonstrating,7. Common femoral vein,8. Greater saphenous vein junction,9. bifurcation Deep and Femoral veins,10. Femoral vein proximal, mid and distal.

11. B-mode, transverse images of the popliteal vein, proximal and distaldemonstrating compression. Longitudinal colour and spectral Doppler ofthe popliteal vein.12. B-mode, transverse images of the posterior tibial and peroneal veinsdemonstrating compression. Longitudinal colour and spectral Dopplerimages of the posterior tibial and peroneal veins.13. B-mode images of the medial and lateral gastrocnemius, soleal, longand small saphenous veins demonstrating compression.