Molecular Imaging in Musculoskeletal Research

Musculoskeletal disorders can affect the muscles, joints, tendons, ligaments and nerves. Three of the most commonly occurring musculoskeletal disorders are osteoarthritis, rheumatoid arthritis and osteoporosis.

Osteoarthritis affects the cartilage in the joints and is most commonly found in the knees, neck, and lower back.

Rheumatoid arthritis is the most common form of inflammatory arthritis; in this case the immune system attacks the tissues lining the joints.

Osteoporosis is characterized by bones becoming fragile and breaking easily due to a loss of calcium.

With the development of multi-pinhole SPECT, it is possible to monitor molecular processes in mice and rats at sub-millimeter resolution, as it is combined with a microCT, exact skeletal anatomic information of the location of the SPECT tracers can be obtained. It is, for example, possible to image arthritic inflammation in mouse-models using 111In labeled cyclic RGD peptide or to image the bone metabolism using 99mTc-MDP.

The high-resolution microCT imaging allows the assessment of bone architecture alterations in osteoarthritis and osteoporosis models. So, it is possible to use this modality for longitudinal monitoring of the osteoarthritis disease process in vivo.