Magnetic resonance imaging helps measure osteoarthritis

Researchers from Australia's Monash University have revolutionised knee scans with the development of new technology that harnesses the power of magnetic resonance imaging (MRI).

The new technique measures loss of knee cartilage and is particularly useful in diagnosing osteoarthritis, one of the leading causes of pain and disability in the community and the most common musculoskeletal disorder affecting Australians.

Dr Flavia Cicuttini, who has spent the past five years perfecting the knee MRI scan, says it is a far more precise way of measuring cartilage loss. Until now, determining the extent of osteoarthritis in a patient has been done mainly with X-rays.

"MRI has often been used in assessing knee joints after injuries, such as in the case of footballers and sports stars, but until now it has not been used much in assessing the level of wear and tear in joints," she said. "X-rays can only detect big changes in the wearing out of joints over a long period of time, and until now there has been no other way to measure slight changes in osteoarthritis.

"But the problem is that X-rays only show bone, not cartilage, so it is a highly inaccurate way of determining the rate of cartilage loss."

The new technique focuses on the knee joint and shows the amount of cartilage, which is particularly useful in diagnosis of osteoarthritis.

"Instead of taking half-an-hour for a full MRI scan, our method only takes five minutes, which significantly cuts the cost," she said. "In time, this technology could be used as a screening tool available to the general public to assess cartilage damage, the extent of the damage and the possibility of the patient developing osteoarthritis.

"We expect in the future doctors will want to look at knee cartilage in much the same way as they are currently doing with bone density scans."

Dr Cicuttini said the team had mastered the technique and had already tested several hundred patients. "Already research from our study group has shown that of the people with osteoarthritis, one third who lost cartilage at the fastest rate over a two-year period were seven times more likely to have a knee replacement within four years.

"This gives strong support for using this method to assess drug therapy and preventative strategies for the condition.

"The ultimate goal of the research is for health practitioners to be able to use the technology to identify new methods to prevent and treat osteoarthritis. In addition, we eventually hope to provide individuals with information on how much knee cartilage they have and so give information of a person's risk of developing severe osteoarthritis."

Dr Cicuttini said most cases of osteoarthritis were found in middle-aged and older people, and more than 90 per cent of knee and hip replacements, which equated to about 40,000 new cases every year, were caused by this degenerative joint disease.

She is working with Monash's Associate Professor David Suter from the Institute of Vision Systems Engineering to fully automate the process.