CPT® Code 77090

Trabecular bone score (TBS), structural condition of the bone microarchitecture; technical preparation and transmission of data for analysis to be performed elsewhere

The Trabecular Bone Score (TBS) is a diagnostic tool used to assess the structural condition of bone microarchitecture, particularly in the context of osteoporosis evaluation and fracture risk prediction. This score is derived from a previously obtained dual X-ray absorptiometry (DXA) image, which is a standard method for measuring bone mineral density. The TBS provides an indirect measurement of bone strength and microarchitecture without the need for invasive procedures. It operates by analyzing pixel gray-level variations within the DXA image of the lower spine, where different types of bone structures exhibit distinct patterns of x-ray absorption. A dense trabecular bone structure will display numerous pixel-to-pixel gray-scale variations with minimal amplitude, indicating a robust bone architecture, while a porous structure will show fewer variations with greater amplitude, suggesting a weaker bone composition. The TBS is calculated through a variogram, which quantifies the differences in gray levels between adjacent pixels, ultimately yielding a score that reflects the trabecular density. A higher TBS indicates a stronger, more fracture-resistant bone microarchitecture, whereas a lower score suggests a higher susceptibility to fractures. The technical preparation and transmission of data for TBS analysis are captured under CPT® Code 77090, which specifically refers to the work involved in preparing and sending the data for further analysis at a different location.