Researchers have come a step closer to detecting the very early changes that indicate the beginning of osteoarthritis (OA) in the knee joint. Diagnosing and treating OA before joint damage occurs could prevent pain and disability for many people, and even delay joint surgery or make it unnecessary. However, X-ray, the current “gold standard” for assessing OA damage, can only detect changes in the joint space that occur later in the disease, after significant damage has already been done. Standard magnetic resonance imaging (MRI) scans are also inconclusive in detecting early degeneration of the cartilage.
Supported by grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), Xiaojuan Li, Ph.D., and her colleagues at the University of California at San Francisco used two specialized types of MRI scans to assess the cartilage of 26 volunteers: 10 with OA of the knee and 16 without OA. The MRI measurements used in this study, , T1-ρ (T1-rho) and T2, showed significantly different values in the OA patients than in the healthy volunteers. When compared with images from X-rays and standard MRI scans, it was clear that these T 1ρ and T2 values correlated with more advanced OA in the knee.
The researchers concluded that these measures may be able to detect very early changes in the biochemical structure of cartilage as it begins to deteriorate, but before significant joint damage or pain develop. A change in the T2 measure may indicate increased water and altered collagen network in the cartilage, an early sign of damage. T1ρ measures can show the loss of proteoglycans (biochemicals consisting of protein and carbohydrate) from the cartilage. Measuring these changes in slightly different ways may provide complementary methods of determining whether a patient is in the very earliest stages of OA.
Detecting these subtle molecular changes with a noninvasive test at an early stage holds promise for treating OA before irreversible damage occurs. With the promise of disease-modifying drugs for OA, as well as improved cartilage resurfacing techniques, early treatment could prevent or delay damage and disability from OA.
Other support for this study came from the National Institute on Aging.
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov .
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Li X et al. In vivo T1ρ and T2 mapping of articular cartilage in osteoarthritis of the knee using 3 T MRI. Osteoarthritis and Cartilage 2007;15:789-797.