Mazzetti Gillian, Berger Claudie, Leslie William D, Hans Didier, Langsetmo Lisa, Hanley David A, Kovacs Christopher S, Prior Jerrilyn C, Kaiser Stephanie M, Davison K Shawn, Josse Robert, Papaioannou Alexandra, Adachi Jonathan R, Goltzman David, Morin Suzanne N
Department of Medicine, McGill University, Montréal, Québec, Canada.
CaMos National Coordinating Centre, McGill University, Montréal, Québec, Canada.
J Clin Densitom. 2017 Apr-Jun;20(2):233-238. doi: 10.1016/j.jocd.2016.11.003. Epub 2016 Dec 26.
Trabecular bone score (TBS) is a gray-level texture measure derived from lumbar spine dual-energy X-ray absorptiometry (DXA) images that predicts fractures independent of bone mineral density (BMD). Increased abdominal soft tissue in individuals with elevated body mass index (BMI) absorbs more X-rays during image acquisition for BMD measurement and must be accommodated by the TBS algorithm. We aimed to determine if the relationship between BMI and TBS varied between 2 major manufacturers' densitometers, because different densitometers accommodate soft tissues differently. We identified 1919 women and 811 men, participants of the Canadian Multicentre Osteoporosis Study, aged ≥40 yr with lumbar spine DXA scans acquired on GE Lunar (4 centers) or Hologic (3 centers) densitometers at year 10 of follow-up. TBS was calculated for L1-L4 (TBS iNsight® software, version 2.1). A significant negative correlation between TBS and BMI was observed when TBS measurements were performed on Hologic densitometers in men (Pearson r = -0.36, p <0.0001) and in women (Pearson r = -0.33, p <0.0001); significant correlations were not seen when TBS was measured on GE Lunar densitometers (Pearson r = 0.00 in men, Pearson r = -0.02 in women). Age-adjusted linear regression models confirmed significant interactions between BMI and densitometer manufacturer for both men and women (p < 0.0001). In contrast, comparable positive correlations were observed between BMD and BMI on both Hologic and GE Lunar densitometers in men and women. In conclusion, BMI significantly affects TBS values in men and women when measured on Hologic but not GE Lunar densitometers. This finding has implications for clinical and research applications of TBS, especially when TBS is measured sequentially on DXA densitometers from different manufacturers or when results from different machines are pooled for analysis.
小梁骨评分（TBS）是一种从腰椎双能X线吸收测定法（DXA）图像中得出的灰度纹理测量值，可独立于骨矿物质密度（BMD）预测骨折。体重指数（BMI）升高的个体腹部软组织增加，在进行BMD测量的图像采集过程中会吸收更多X射线，TBS算法必须对此加以考虑。我们旨在确定BMI与TBS之间的关系在2家主要制造商的骨密度仪之间是否存在差异，因为不同的骨密度仪对软组织的处理方式不同。我们纳入了1919名女性和811名男性，他们均为加拿大多中心骨质疏松研究的参与者，年龄≥40岁，在随访第10年时用GE Lunar（4个中心）或Hologic（3个中心）骨密度仪进行了腰椎DXA扫描。使用TBS iNsight®软件2.1版计算L1-L4的TBS。当在Hologic骨密度仪上对男性（Pearson相关系数r = -0.36，p <0.0001）和女性（Pearson相关系数r = -0.33，p <0.0001）进行TBS测量时，观察到TBS与BMI之间存在显著负相关；而在GE Lunar骨密度仪上进行TBS测量时未观察到显著相关性（男性Pearson相关系数r = 0.00，女性Pearson相关系数r = -0.02）。年龄调整后的线性回归模型证实，男性和女性的BMI与骨密度仪制造商之间均存在显著交互作用（p <0.0001）。相比之下，在男性和女性中，Hologic和GE Lunar骨密度仪上的BMD与BMI之间均观察到类似的正相关。总之，在Hologic骨密度仪上测量时，BMI对男性和女性的TBS值有显著影响，而在GE Lunar骨密度仪上则不然。这一发现对TBS的临床和研究应用具有启示意义，尤其是当在不同制造商的DXA骨密度仪上依次测量TBS时，或者将不同机器的结果汇总进行分析时。
