Trabecular bone score (TBS): available knowledge, clinical relevance, and future prospects

Abstract

The diagnosis of osteoporosis rests on areal bone mineral density (BMD) measurement using DXA. Cancellous bone microarchitecture is a key determinant of bone strength but cannot be measured using DXA. To meet the need for a clinical tool capable of assessing bone microarchitecture, the TBS was developed. The TBS is a texture parameter that evaluates pixel gray-level variations in DXA images of the lumbar spine. The TBS variations may reflect bone microarchitecture. We explain the general principles used to compute the TBS, and we report the correlations between TBS and microarchitectural parameters. Several limitations of the TBS as it is used now are pointed out. We discuss data from currently available clinical studies on the ability of the TBS to identify patients with fractures and to evaluate the fracture risk. We conclude that this new index emphasizes the failure of the BMD T-score to fully capture the fragility fracture risk. However, although microarchitecture may influence the TBS, today, to the best of our understanding, there is no sufficient evidence that a TBS measurement provides reliable information on the status of the bone microarchitecture for a given patient. The TBS depends on gray-level variations and in a projectional image obtained in vivo, these variations can have many causes. Nevertheless, as clinical studies suggest that the TBS predicts the risk of fracture even after adjustment for BMD, we are encouraged to learn more about this score. Additional studies will have to be performed to assess the advantages and limitations of the TBS, in order to ensure that it is used appropriately in clinical practice.

Short-term Precision Error in Dual Energy X-Ray Absorptiometry, Bone Mineral Density and Trabecular Bone Score Measurements; and Effects of Obesity on Precision Error

“…This is consistent with the 1.45% CV reported by Krueger et al [24] for the L1-L4 ROI in a comparable precision study on GE Lunar Prodigy. The limited information on in vivo reproducibility available from Bousson et al [19] demonstrated a 1.2%…”

“…Higher body mass index (BMI) has been demonstrated to contribute to increased DXA precision error that may be attributable to greater tissue inhomogeneity at the site of the lumbar spine and a reduction in signal to noise ratio in larger participants [17] . Whilst short-term precision has been reported for DXA BMD measurement [18,22] information is very limited regarding in vivo short-term precision error (STPE) for TBS [19] . This study investigated the STPE of TBS and BMD and the effect of obesity on precision error.…”

Bone quality, as measured by trabecular bone score, in patients with primary hyperparathyroidism

“…The trabecular bone score (TBS) is a grey-level texture measurement based on the use of experimental variograms of two-dimensional (2D) projection images acquired during a dual-energy X-ray absorptiometry (DXA) lumbar spine (LS) scan (13). It may be used for the routine evaluation of bone micro-architecture, as it is strongly correlated with bone micro-architecture, regardless of BMD (14,15).…”

A Review of the Mechanisms, Diagnosis and Preventative Treatment of Osteoporotic Fragility Fractures in Patients With Type 2 Diabetes Mellitus

“…TBS provides an alternative measurement of bone architecture using DXA scan images. Using pixel-by-pixel analysis of DXA scans of the lumbar spine, TBS provides an analogue of trabecular bone structure that has been demonstrated to predict fracture risk independently of BMD [30,31]. However, this has been demonstrated to have a higher precision error in an obese population [32].…”