GE Introduces Imaging for Patients with Metal Implants

GE Healthcare has developed new technology that addresses the need for imaging patients with metal implants. The Mavric SL technology recently was unveiled at the Hospital for Special Surgery in New York City, N.Y.

According to GE, the clinical need to more accurately image soft tissue and bone in patients with joint replacements and other implanted devices is expected to grow significantly in the next twenty years, accelerated by gains in life expectancy and a desire to remain active in later years. Each year 2.9 million joint replacements take place worldwide with 1 million Americans receiving a hip or knee replacement. In the U.S., by 2030, the annual demand for primary total hip arthroplasties will grow to 572,000. Knee arthroplastic procedures are expected to rise to 3.48 million.

“This was driven by clinical need,” said Hollis Potter, M.D., chief of magnetic resonance imaging (MRI) at Hospital for Special Surgery and a lead member of the development team. “My orthopedic colleagues have said, I have patients who have orthopedic implants, and they hurt. I’ve done an X-ray, I’ve examined them, I’ve done everything I think I can to help them and I can’t figure out how to help this patient.”

While the vast majority of joint replacement procedures are successful, complications that can arise include infection, dislocation, blood clots, and nerve and blood vessel injury. Patients also may develop pain and/or a change in the way they walk or run. This can be due to inflammation of the joint lining (synovitis) in patients with metal-on-metal hip implants. This may occur long before symptoms appear. MRI is able to detect inflammation in both symptomatic and asymptomatic patients, helping to identify those patients who need revision surgery before tissue sustains further damage that makes a revision more difficult.

This rising need for imaging around implants presents a challenge for MRI. It long has been considered the most effective technique in which to assess soft tissue response and bone loss around metallic implants. However, MRIs operate through a very high-powered magnet. As a result, physicians only can use MRI to image implants made from carefully selected alloys—and still, paramagnetic metal used in joint replacements and implanted devices can cause magnetic field distortion and signal void, producing images that are of non-diagnostic quality.

Mavric SL is designed to address this gap and minimize image distortion in the areas near MRI- conditional metal implants by using a technique to collect multiple snapshots taken at different frequencies. These individual snapshots are then combined to form the final image. A deblurring post-processing technique then is implemented to optimize the volume combination process.

The technology, GE hopes, will save both human and economic costs by providing previously inaccessible clinical information, speeding up diagnosis. Such images could be used to help explain to patients why they are in pain, and patients also will benefit from this non-invasive procedure that allows treatment decisions to be made in less time and also may reduce the need for exploratory surgery.

Mavric SL will be available in two months as a software upgrade for use with GE 1.5T and 3.0T MRI systems.

Headquartered in the United Kingdom, GE Healthcare is a unit of General Electric Company.