Imaging Method Measures GAG Loss to Diagnose Early Osteoarthritis

A new imaging method could make it easier to diagnose and monitor joint conditions, like osteoarthritis and degenerative disc disease. Previous research suggested that as osteoarthritis progresses in humans, the cartilage padding surrounding joints begins to lose molecules called glycosaminoglycans (GAGs). Now, researchers from New York University and Tel Aviv University have reported a new method for measuring GAG concentration using magnetic resonance imaging (MRI), according to the February 11, 2008 Proceedings of the National Academy of Sciences.

Measuring the concentration of GAGs in cartilage can indicate the progress of joint degeneration, but current methods of estimating the tissue loss have limitations. GAG molecules have proton groups that are not tightly tethered together. The researchers investigated whether MRI could measure proton exchange in GAGs, allowing doctors to estimate the molecule's concentrations in a patient's joints. The researchers used human tissue samples and a normal MRI scanner to demonstrate that GAG protons form a natural contrast agent against water protons in the body, allowing them to assess joint damage relatively easily. Further work with this chemical exchange saturation method (gagCEST) could provide a non-invasive way to diagnose osteoarthritis in its earliest stages.

Related Resources:

• Diagnosis of Osteoarthritis
• X-ray Evidence of Osteoarthritis
• Cartilage: 10 Things You Should Know
• Recognizing Early Osteoarthritis Symptoms

_{Photo by Annett Vauteck (iStockphoto)}