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Sodium MRI shows arthritis long before onset of physical symptoms:

Dr Garry Gold, an associate professor of radiology at the Stanford University School of Medicine has improved an old imaging technology called sodium MRI to diagnose osteoarthritis as long as decades before the onset of physical symptoms.

While standard MRI gives a reasonable display of overall cartilage structure, it doesn’t tell a diagnostician much about the quality of that cartilage.

“If you look into a big house and you see that it’s standing up,” Gold said, “you may assume it’s going to be safe in the event of an earthquake. But without closer inspection, you don’t know much about the integrity of the structure.” If standard MRI is akin to a view of standing timber in the house, the version Gold is using, called sodium MRI, enables the visualization of dry rot infecting and weakening the wood.

A key structural material in cartilage, called glycosaminoglycan, occurs in a complex with sodium, an elemental metal that has its own set of excitation and relaxation frequencies and is more restricted to cartilage than water is. Sodium MRI has been around for years, but until recently it couldn’t be used in clinical settings. For one thing, the magnets employed to excite sodium atoms were too puny, making crisp resolution possible only with tiny creatures such as mice. Gold and his colleague Brian Hargreaves, PhD, assistant professor of radiology at Stanford, have designed improved magnets and software to scale up the technology for human application. Gold and Hargreaves’ project is being conducted with funding from the National Institutes of Health and GlaxoSmithKline, an international pharmaceutical company. Neither researcher owns stock in, or receives consulting fees from, the company.

Working with Hargreaves, Gold has imaged the knees of about a dozen volunteers who have suffered a recent ACL injury. In every case so far, significant losses of glycosaminoglycan can be glimpsed under sodium MRI scanning, despite the absence of any sign of damage to cartilage observed with standard MRI.

Almost invariably, sodium MRI scans of the injured knee - but not of the other, uninjured one - reveal glycosaminoglycan deficits within three years of the injury, potentially enabling a vastly accelerated diagnosis.

This ought to speed the development of new therapies, and radically lower the cost of doing so, Gold said. The idea is to be able to use glycosaminoglycan loss as a “surrogate marker” of impending osteoarthritis, much as high LDL levels are used to flag people at risk of heart disease - perhaps years before actual symptoms of heart disease manifest.

Read the entire article here.

The original news release from Stanford School of Medicine is here.