National Physical Laboratory

Pain-free measurement of leg ulcers

A new device to make non-contact, pain free measurements of leg ulcers.

The Challenge

Ulcers are breaks in the layers of skin that fail to heal, the most common cause being poor blood circulation. Chronic leg and foot ulcers affect up to 1 in 100 people - mainly the elderly and diabetics. The ulcers can be extremely painful and greatly reduce the sufferer's quality of life.

The wounds can heal but only do so very slowly. Doctors typically measure the wound area and volume on a weekly basis to monitor healing. The area may be measured by placing a transparent sheet on top of the wound, tracing the wound perimeter and counting the squares inside the line. The volume may be measured by filling the wound with saline from a syringe - the amount dispensed is the wound volume. These contact methods are inaccurate, slow, carry a cross infection risk, and are painful to the patient.

The Solution

Isotec Imaging developed an inexpensive portable stereo-optical system, 'MAVIS', for non-contact measurement of area, volume and colour that avoids these problems. Colour is important in monitoring the progress of the wound. However it is essential that the instruments are calibrated to give consistent measurements.

Through a Joint Industry Project, Isotec and NPL developed dimensional artefacts with flesh-like textured surfaces to enable calibration. A pilot clinical trial at the Royal National Hospital for Rheumatic Diseases NHS Trust was positive and the feedback was incorporated into the measurement procedure. MAVIS was also appraised at a number of medical institutes in Europe.

The Impact

As a result of the project, Isotec could demonstrate to its customers that the instrument yields more precise measurements than the current clinical practice and its sales more than doubled.

Isotec Ltd has since changed its name to Photometrix Imaging Ltd and has teamed-up with Perry Baromedical Corporation in Florida. Perry Baromedical produce the MAVIS instrument under licence and production started in 2010.

Dr Peter Plassmann, of Photometrix Imaging Ltd says:

"It is now clear to us that the original Mavis-II calibration artefacts were one of the key components in successfully bringing the product to market. Even the most sceptical customers are convinced when they can try a measurement of the hyper-precise NPL artefacts and find that the figures the system produces are actually correct. Everyone has a ruler at home to check length measurements but who has a set of volume benchmarks?"

Find out more about NPL's research in Dimensional Metrology

Do you have a measurement challenge that you'd like NPL's help with? If so, why not apply for NPL's Technology Innovation Fund ?

Last Updated: 18 Nov 2013
Created: 14 Oct 2010

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