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Human replicant aids MRI research

6 October 2014

PhD candidate Steven McCabe, the phantom case and Professor Jonathan Scott

Looking for solutions for MRI scanning: PhD candidate Steven McCabe, the phantom case and Professor Jonathan Scott.

It may just look like a clear acrylic human-shaped box, but it is hoped this replicant – or phantom case - will play a vital role in the future of magnetic resonance imaging (MRI) scanning.

The phantom case was built by Technical Officers Martin Gore and Michael Hoogeveen in the University of Waikato’s Science and Engineering Workshop. It is designed to be filled with a phosphate buffered saline jelly into which electrodes will be inserted before the case is run through an MRI scanner.

Looking for a new solution

Engineering Professor Jonathan Scott is on the search for a new and safer design for implantable electrodes, so that people with medical implants to which the electrodes are connected can have MRI scans, something that can’t be done at present.

“So many people are fitted with medical equipment such as spinal cord, deep brain and cochlear implants and pacemakers, but if you have one of these devices, you can’t go into an MRI machine because of the electromagnetic and magnetic risks. Most people are aware of the magnetic risk, where an object can be pulled out of place in the body. However, an MRI machine also has 10 times the Radio Frequency (RF) heating power of a microwave oven. This RF field strength is so great that an electrode attached to an implant can heat up and cook the area surrounding it. Our goal is to find a non-magnetic material for the electrode that won’t be affected by the RF fields.”

The need for electrodes that were MRI-safe

It was by chance that Professor Scott became involved in this project, during a three-month study leave project in Sydney in 2012/13 at National ICT Australia (NICTA), Australia’s Information Communications Technology Research Centre of Excellence. While at NICTA, Professor Scott got to know staff at Saluda, a spin-off company from NICTA, who said they had a problem with recipients of their spinal cord implants not being able to undergo MRI scans.

 “I’d never heard of this before,” says Professor Scott. “They told me they’d love to be able to use electrodes that were MRI-safe, but that nothing like this had been developed before. I knew I just had to follow that up.”

Providers of MRI facilities such as Midland MRI and River Radiology in Hamilton are equally concerned with the problem. They turn away virtually all patients carrying medical implants.

Starting electrode trials

Professor Scott and PhD candidate Steven McCabe are about to start electrode trials in the phantom case in the next couple of months. “We will try out a number of ideas in the hope of finding something that works, something that has a clever twist to it. We’re very excited about being involved in solving this problem as it will open up MRI scans for people who can’t have them at the moment.”

Professor Scott says one of the major assets of the University is the Science and Engineering Workshop. “The guys in there can make anything we need, from the strange to the merely unusual. We’re extremely lucky to have such a well-equipped workshop run by such creative guys.”