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Duplex Ultrasound Scanning


Duplex Ultrasound scanning - the test that has revolutionised varicose veins diagnosis and treatment

What is duplex ultrasound scanning?

Most people are aware of ultrasound scanning as it is commonly used during pregnancy to see the fetus, or in the emergency department to see a gallbladder, aortic aneurysm or other medical problem.

This sort of ultrasound scanning is medically known as ‘grey scale’ ultrasound scanning or more correctly ‘B-mode’ ultrasound scanning.

In greyscale or B-mode ultrasound scanning, a black and white picture is seen. The picture is made up of reflections of ultrasound from deep within the body.

Ultrasound cannot travel through air and so a gel is placed on the skin at the point of examination. The ultrasound probe is then placed on the gel and ultrasound is beamed into the body through the probe. The ultrasound bounces off any structures within the body and the ultrasound echoes reflect back to the same probe. These echoes are then transmitted back to the machine and a black and white picture is generated by the computer software inside it.

So what is “duplex” ultrasound?

The word ‘duplex’ means ‘two’ so duplex ultrasound means that there is something added to the top of the grey scale ultrasound picture.

The vein experts at The Whiteley Clinic do not want to see the veins on grey scale ultrasound. They are much more interested in seeing which way the blood is flowing inside the veins. A grey scale ultrasound will only show us where the veins are. It does not show flow within the veins.

There is another ultrasound technique called ‘Doppler’ ultrasound. This is a technique named after a famous scientist called Christian Doppler. The ’Doppler effect’ can be used to see moving blood within veins and other blood vessels in the body.

Ultrasound from the duplex ultrasound machine is beamed into the body through a probe. A black and white picture is made first, exactly as in greyscale ultrasound imaging. Then, in a fraction of a second, the duplex ultrasound machine checks to see whether any of the ultrasound has changed by the Doppler effect in the picture. If it has, then the machine puts a colour of blue or red onto the greyscale image so that the flow can be clearly seen.

This is repeated many times a second so that the flow can be seen as a real time movie.

In addition, due to the physics of the machine, it is possible to measure both the direction and speed of the flow. If needed, a Doppler ‘waveform’ can also be measured.

Duplex ultrasound is the combination of two different sorts of ultrasound ie.a greyscale picture of the area being examined plus an overlying Doppler image in colour to show blood flow.

This is one of the few areas in medicine where we can actually observe exactly what we want to see in real time without any needles, injections or x-rays. It is thanks to duplex ultrasound scanning that the new understanding of vein problems and new treatments championed by The Whiteley Clinic have been possible.

Who should perform duplex ultrasound scans?

As with all electronic devices, advances over the last few years have increased the speed of processing and decreased the costs.

It is now possible to get inexpensive duplex ultrasound machines. As there are no injections or x-rays involved, many doctors or other healthcare professionals have started using them often without a full understanding of the physics and pathophysiology of the condition they are examining. It is not uncommon for doctors to start scanning with no training or only minimal training.

The Whiteley Clinic trained vascular scientists spend several years learning ultrasound physics, how to get the best out of their machine and exactly what they should be scanning to get the information required. Once this level of training has been achieved and an appropriate exam (such as the SVT or RVT) has been attained, The Whiteley Clinic then takes selected vascular scientists and give them additional training in the Whiteley Protocol. Depending on the vascular scientist, this can be anywhere from six months to 2 years extra training on top of the usual ultrasound training for vascular scientists.

Therefore legally, although anyone can perform a venous duplex ultrasound scan, the chances of getting a correct diagnosis and subsequently the correct treatment depends on the skills and experience of the person doing the scan and the duplex ultrasound scan machine itself.

By ensuring that all of our vascular scientists are fully qualified in venous duplex ultrasound scan and then additionally trained in the Whiteley Protocol, we can be certain that the venous duplex ultrasound scans performed at The Whiteley Clinic are accurate and can be used to recommend optimally tailored treatment plans for each patient.

Read more on the reasons why you should be worried if a vein surgeon is doing their own duplex ultrasound scans.