Trabecular Bone Score for GPs

Trabecular Bone Score (TBS) is a relatively new technology used to assist GPs and specialists in clinical decision-making when it comes to patients who are “on the borderline”, when it comes to bone density. It may not be clear, from a patient’s BMD, whether they are moderate or high risk for future fracture. The lumbar Trabecular Bone Score can be used, in conjunction with the BMD value, to give more of a sense of whether the patient is high risk. A “traffic light system”, seen below, can be used to aid your decision making.

TBS is basically a proxy for bony microarchitecture. Two post-menopausal women with identical BMD values may have very different bony microarchitecture. Thus, one might have a much higher risk of fracture due to trabecular thinning or disintegration, while the other has excellent microarchitecture and a lower risk of fracture. The ability, via TBS, to differentiate between these two ladies should hopefully allow the doctor to increase their clinical certainty, and either reassure the latter patient, or treat the former more aggressively than would otherwise have occurred.

Here are some key points regarding TBS (based on this article– Journal of Bone and Mineral Research, Vol. 29, No. 3, March 2014, pp 518–530):

  • The trabecular bone score (TBS) is a gray‐level textural metric that can be extracted from the two‐dimensional lumbar spine dual energy X‐ray absorptiometry (DEXA) image.
  • TBS is related to bone microarchitecture and provides skeletal information that is not captured from the standard bone mineral density (BMD) measurement. Based on experimental variograms of the projected DXA image, TBS has the potential to discern differences between DXA scans that show similar BMD measurements.
  • An elevated TBS value correlates with better skeletal microstructure; a low TBS value correlates with weaker skeletal microstructure.
  • Lumbar spine TBS has been evaluated in cross-sectional and longitudinal studies, and the following is the consensus, at this point:
    1. TBS gives lower values in postmenopausal women and in men with previous fragility fractures than their non-fractured counterparts;
    2. TBS is complementary to data available by lumbar spine DEXA measurements;
    3. TBS results are lower in women who have sustained a fragility fracture but in whom DEXA does not indicate osteoporosis or even osteopaenia;
    4. TBS predicts fracture risk as well as lumbar spine BMD measurements in postmenopausal women;
    5. Efficacious therapies for osteoporosis differ in the extent to which they influence the TBS;
    6. TBS is associated with fracture risk in individuals with conditions related to reduced bone mass or bone quality.

TBS is only offered on the Central Coast at Riverside Medical Imaging. We have invested heavily in this technology because we believe that it has the potential to assist GPs and endocrinologists to “sort the sheep from the goats” when it comes to how aggressively to treat a patient with low bone density.

For more information, please phone us to discuss an education session. We also have research papers available for GPs and specialists to peruse.

References

Journal of Bone and Mineral Research, Vol. 29, No. 3, March 2014, pp 518–530

Journal of Bone and Mineral Research, Vol. 26, No. 11, November 2011, pp 2762–2769

Anderson, K. B., Holloway‐Kew, K. L., Hans, D. , Kotowicz, M. A., Hyde, N. K. and Pasco, J. A. (2019), Reference Ranges for Trabecular Bone Score in Australian Men and Women: A Cross‐Sectional Study. JBMR Plus, 3: e10133. doi:10.1002/jbm4.10133