photo: arthritis in the knee, MR image
Osteoarthritis is the most common
type of knee arthritis; © wikipedia/
Scuba-limp

Assessing the local variations in GAGs are of significant interest for the study of cartilage biology and for the diagnosis of cartilage disease like osteoarthritis, which afflicts more than 27 million people in the United States.

Articular or joint cartilage is the smooth hydrated tissue in the ends of bones in load-bearing joints, such as knees, hips and shoulders. The loss of GAGs from these joints is the hallmark of osteoarthritis, a degenerative joint disease in which wear or trauma results in damage to the cartilage surface.

To better see the differentiation between healthy and unhealthy cartilage, contrast agents provide the visual tool to assess GAG content. However, the current contrast agents used with computer tomography or magnetic resonance imaging (MRI) rely on limited diffusion of the anionic or negative ion-charged contrast agents into the target tissue, the study noted.

So researchers hypothesized that cationic contrast agents would be electrostatically attracted to anionic GAGs to provide a more sensitive technique for imaging cartilage. And they focused on using the more widely accessible CT equipment because it can image cartilage and bone simultaneously, enable rapid three-dimensional reconstruction of the tissue and achieve higher spatial resolution over shorter acquisition times compared to MRI systems.

The team synthesized three cationic or positive ion-charged iodine-based X-ray contrast agents. Using the femur of a rabbit, they reported gaining better and more specific images for the cartilage tissue than with current negative ion-charged contrast agents.

COMPAMED.de; Source: Boston Medical Center