Rationale, design and clinical performance of the mechanical response tissue analyser: a non-invasive technology for measurement of long bone bending stiffness.

Prediction of osteoporotic fractures is currently an imperfect science and new tools are desperately needed to identify at-risk patients at an earlier stage in the disease process. The mechanical response tissue analyser (MRTA) is a novel, non-invasive, radiation-free device that measures the bending stiffness of long bones in vivo, an indicator of a bone's ability to resist deformation under a given load and a strong predictor of long bone structural integrity and strength. Bone bending stiffness measured with the MRTA has been consistently shown to be a stronger predictor of post-mortem and ex vivo bone breaking strength compared to bone mineral measured with dual-energy X-ray absorptiometry. Bone bending stiffness measured with MRTA also decreases with advanced age and disease states and increases with chronic physical activity, independent of bone mineral changes. The MRTA measures different parameters than DXA (bone quality vs bone mineral content and density) and may be a more robust tool for identifying those at risk for fracture. Research initiatives focused on improving long-term repeatability and optimizing the signal-to-noise ratio of the measurement are currently underway to further advance the clinical usefulness of this technology.