CPT® Code 77091

The Trabecular Bone Score (TBS) is a sophisticated method utilized for assessing osteoporosis and estimating an individual's risk of fractures. This evaluation is typically performed alongside a separate bone mineral density (BMD) examination. The TBS offers an indirect measurement of the microarchitecture and strength of bone in a non-invasive manner, which is crucial for understanding bone health. The process involves analyzing pixel gray-level variations derived from a previously obtained dual X-ray absorptiometry (DXA) image of the lower spine. DXA imaging operates on the principle that different types of body tissues absorb X-ray photons differently, utilizing both high and low energy X-ray beams. In the context of TBS, a dense trabecular bone structure will exhibit a significant number of pixel-to-pixel gray-scale variations with minimal amplitude, indicating a robust bone microarchitecture. Conversely, a porous bone structure will show fewer variations with greater amplitude, suggesting a weaker bone composition. The TBS calculation is based on a variogram, which quantifies the sum of squared gray-level differences between pixels in the DXA image. A higher TBS score indicates greater trabecular density and a stronger, more fracture-resistant bone microarchitecture, while a lower score suggests a weaker, more fracture-prone structure. The final TBS score is interpreted to provide a comprehensive report on the patient's fracture risk, which is essential for guiding clinical decisions and patient management.