Kaiser Jarred, Allaire Brett, Fein Paul M, Lu Darlene, Adams Alexander, Kiel Douglas P, Jarraya Mohamed, Guermazi Ali, Demissie Serkalem, Samelson Elizabeth J, Bouxsein Mary L, Morgan Elise F
Department of Mechanical Engineering, Boston University, Boston, MA, USA.
Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.
J Bone Miner Res. 2020 Apr;35(4):641-648. doi: 10.1002/jbmr.3946. Epub 2020 Jan 16.
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 L 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/cm , 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.
椎体中心小梁骨密度的空间异质性与椎体强度相关，这可以解释为什么体积骨密度（vBMD）在识别骨折风险方面表现出低敏感性。本研究评估小梁vBMD的异质性和空间分布是否与现患椎体骨折相关。我们检查了弗雷明汉心脏研究多探测器CT研究中148名参与者的L椎体的体积定量计算机断层扫描（QCT）图像。在这些个体中，37人被确定为现患骨折病例，111人为对照，按性别和年龄匹配，每个病例有三个对照。在椎体的5毫米连续立方区域内计算vBMD。计算了两种异质性指标：（i）四分位数间距（IQR）；（ii）四分位变异系数（QCV）。还计算了小梁vBMD空间分布的比率：前/后、中央/外周、上/中横、下/中横。使用Wilcoxon秩和检验和t检验比较病例组和对照组之间的异质性和空间分布，并通过独立于整体vBMD的条件逻辑回归检验与现患骨折的相关性。现患骨折病例的平均±标准差整体vBMD较低（134±38对165±42mg/cm，p<.001），QCV较高（0.22±0.13对0.17±0.09，p = .003），前/后rBMD较低（0.65±0.13对0.78±0.16，p<.001）。QCV与现患骨折几率增加呈正相关（OR 1.61；95%CI，1.04至2.49；p = .034），但这种相关性并非独立于整体vBMD（p = .598）。前/后小梁vBMD比率增加与独立于整体vBMD的现患骨折几率降低相关（OR 0.38；95%CI，0.20至0.71；p = .003）。总之，与整体vBMD无关，椎体中心前侧小梁vBMD增加而非小梁vBMD异质性增加与现患骨折风险降低相关。小梁vBMD的区域测量有助于确定椎体骨折的风险和潜在机制。©2019美国骨与矿物质研究学会。
