The spatial heterogeneity in trabecular bone density within the vertebral centrum is associated with vertebral strength and could explain why volumetric bone mineral density (vBMD) exhibits low sensitivity in identifying fracture risk. This study evaluated whether the heterogeneity and spatial distribution of trabecular vBMD are associated with prevalent vertebral fracture. We examined the volumetric quantitative computed tomography (QCT) scans of the L3 vertebra in 148 participants in the Framingham Heart Study Multidetector CT study. Of these individuals, 37 were identified as cases of prevalent fracture, and 111 were controls, matched on sex and age with three controls per case. vBMD was calculated within 5-mm contiguous cubic regions of the centrum. Two measures of heterogeneity were calculated: (i) interquartile range (IQR); and (ii) quartile coefficient of variation (QCV). Ratios in the spatial distributions of the trabecular vBMD were also calculated: anterior/posterior, central/outer, superior/mid-transverse, and inferior/mid-transverse. Heterogeneity and spatial distributions were compared between cases and controls using Wilcoxon rank sum tests and t tests and tested for association with prevalent fractures with conditional logistic regressions independent of integral vBMD. Prevalent fracture cases had lower mean ± SD integral vBMD (134 ± 38 versus165 ± 42 mg/cm3 , p < .001), higher QCV (0.22 ± 0.13 versus 0.17 ± 0.09, p = .003), and lower anterior/posterior rBMD (0.65 ± 0.13 versus 0.78 ± 0.16, p < .001) than controls. QCV was positively associated with increased odds of prevalent fracture (OR 1.61; 95% CI, 1.04 to 2.49; p = .034), but this association was not independent of integral vBMD (p = .598). Increased anterior/posterior trabecular vBMD ratio was associated with decreased odds of prevalent fracture independent of integral vBMD (OR 0.38; 95% CI, 0.20 to 0.71; p = .003). In conclusion, increased trabecular vBMD in the anterior versus posterior centrum, but not trabecular vBMD heterogeneity, was associated with decreased risk of prevalent fracture independent of integral vBMD. Regional measurements of trabecular vBMD could aid in determining the risk and underlying mechanisms of vertebral fracture. © 2019 American Society for Bone and Mineral Research.

中文翻译：

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腰椎椎内小梁骨矿物质密度的异质性和空间分布与普遍的椎体骨折有关。


椎体中心内骨小梁密度的空间异质性与椎体强度相关，并且可以解释为什么体积骨矿物质密度（vBMD）在识别骨折风险方面表现出低敏感性。本研究评估了小梁 vBMD 的异质性和空间分布是否与常见的椎体骨折相关。我们检查了 Framingham 心脏研究多探测器 CT 研究中 148 名参与者的 L3 椎骨体积定量计算机断层扫描 (QCT) 扫描。在这些人中，37 人被确定为普遍骨折病例，111 人为对照，性别和年龄相匹配，每个病例有 3 名对照。 vBMD 是在中心 5 毫米连续立方区域内计算的。计算了两种异质性度量：（i）四分位距（IQR）； (ii) 四分位数变异系数 (QCV)。还计算了小梁 vBMD 空间分布的比率：前/后、中央/外、上/中横向和下/中横向。使用 Wilcoxon 秩和检验和 t 检验比较病例和对照之间的异质性和空间分布，并使用独立于积分 vBMD 的条件逻辑回归测试与常见骨折的关联。常见骨折病例的平均±SD积分vBMD较低（134 ± 38 vs 165 ± 42 mg/cm3，p < .001），较高的QCV（0.22 ± 0.13 vs 0.17 ± 0.09，p = .003），以及较低的前/后位rBMD（0.65 ± 0.13 对比 0.78 ± 0.16，p < .001）高于对照组。 QCV 与骨折发生率增加呈正相关（OR 1.61；95% CI，1.04 至 2.49；p = .034），但这种关联并不独立于积分 vBMD（p = .598）。 前/后小梁 vBMD 比率增加与骨折发生率降低相关，与积分 vBMD 无关（OR 0.38；95% CI，0.20 至 0.71；p = 0.003）。总之，前椎体与后椎体的小梁 vBMD 增加，而非小梁 vBMD 异质性，与普遍骨折风险降低相关，与整体 vBMD 无关。小梁 vBMD 的区域测量有助于确定椎骨骨折的风险和潜在机制。 © 2019 美国骨与矿物质研究学会。