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Varicose Vein Assessment

Proper treatment of venous disease is dependent upon an accurate diagnosis. A clinical examination is essential in assessing the extent of the venous problem. A variety of methods may be employed, including duplex ultra sound imaging which is used to obtain pictures of the deep and superficial veins.
Ultrasound is a non-invasive test that uses high frequency sound waves to produce an image on a screen.

Ultrasound is perfectly safe and there is no need for the use of sedative, needles or harmful radiation; and it can be done in an out-patient setting with no need for special preparations.

Ultrasound gel is placed on the skin to create a good contact and an ultrasound probe (transducer) is passed over the area to be examined. The transducer sends sounds waves into the tissue and then receives the returning echoes. The echoes are reflected back differently from bone, muscle, fat and other surfaces. The computer processor within the ultrasound machine then turns this information into a black and white picture. This is why ultrasound is often called "Grey Scale Ultrasound". Ultrasound examination has become a well known technique with in the UK, predominantly as a result of its widespread use in pregnancy monitoring.

Venous ScanDuplex ultrasound is a refinement of the technique, which started to appear in the UK towards the end of the 1980’s and has continued to grow since. Duplex ultrasound uses two display elements (hence the word duplex), grey scale imaging and the use of colour to demonstrate blood flow and its direction.

To determine the colour aspect of the display, the ultrasound equipment looks at the frequency of the returning echo in comparison to the ultrasound that was sent in to the body. As the ultrasound bounces off a moving target its frequency changes, either increasing if the target is moving towards the probe, or decreasing if it is moving away.
In fact, colour duplex scanning has revolutionised the investigation of the lower limb venous system as a result of its ability to instantly visualise blood flow and its direction. Thus, reflux at the saphenofemoral junction, at the saphenopopliteal junction, and within the deep venous system, including the popliteal vein beneath the knee and the gastrocnemius veins, can be detected without invasive techniques. Although venous reflux can be assessed with a pencil Doppler, this technique misses 12% of saphenofemoral and 20% of saphenopopliteal junction reflux compared with colour duplex scanning.

Colour duplex scanning of saphenopopliteal junctionThis shift in frequency is known as the “Doppler shift” and is named after the Austrian physicist, Christian Doppler, who first described the phenomenon long before ultrasound was thought of. An analogy is to think of the change in tone as a siren gets closer and then moves away from you. This change is tone is the result of a Doppler shift. By noting the magnitude of the Doppler shift, the Ultrasound unit can determine if a target is in motion, its relative direction and speed. The image can then be create to show this graphically, using colour to show direction and colour intensity to show speed.

Note: The Ultrasound does not determine if it is venous or arterial flow, only its direction. So, contrary to popular belief, red colouring does not depict arterial flow and blue venous.

The information can also be displayed as a graph of frequency shift against a time line. This allows quantitative assessment of blood flow to be made, as well as the qualitative assessment of the graphical duplex display.

The current practice for assessment of varicose veins using all three Ultrasound techniques; grey scale, colour imaging and Doppler graphs to provide a comprehensive assessment of blood flow.

In this way, the blood flow with in the veins can be seen, areas of reverse flow assessed and occlusion of veins demonstrated.

The test is generally performed by Vascular Scientists (Sonographers specialising in Vascular Ultrasound).  The vascular scientist will construct a detailed report of the leg(s), not only assessing whether or not the veins are working; but also commenting on the size of veins, how superficial the veins are and their tortuosity. This is known as “vein mapping”.

In this way you can be certain that the correct veins are treated, in the most appropriate manner for that particular vein

Continue here to read about Varicose Vein treatment options