OBJECTIVE To explore the characteristics of vertebral CT Hounsfield units (HU) in elderly patients with acute vertebral fragility fractures. METHODS A total of 299 patients aged ≥ 65 years with acute vertebral fragility fractures were retrospectively reviewed, and 77 patients of them were age- and sex-matched with 77 control patients without any fractures. The vertebral HU value of L1(L1-HU) was measured, and T12 and L2 were used as alternatives for L1 in the case of L1 fracture. RESULTS There were 460 thoracic and lumbar vertebral fractures in the 299 elderly patients, including 349 acute vertebral fragility fractures and 111 chronic fractures. The average L1-HU value was 66.0 ± 30.6 HU and showed significant difference among patients having different numbers of vertebral fractures (one fracture: 73.3 ± 27.0 HU, two fractures: 58.7 ± 32.5 HU, three or more fractures: 40.7 ± 28.8 HU; P < 0.001). As for the 1:1 age- and sex-matched patients, the L1-HU of the 77 patients with fractures was lower than that of the control patients (70.6 ± 23.4 HU vs. 101.5 ± 36.2 HU, P < 0.001). The area under the receiver operating characteristic curve of using L1-HU to differentiate patients with fractures from controls was 0.77(95% CI 0.70-0.85, P < 0.001). The cutoff value had high specificity of 90% or high sensitivity of 90% to identify patients with fractures of 60 HU and 100 HU, respectively. CONCLUSIONS The elderly patients with acute vertebral fragility fractures have much lower HU values than those without fractures. Moreover, the lower the vertebral HU value is, the more likely the patients have more than one vertebral fracture. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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老年急性椎体脆性骨折患者的CT CT Hounsfield单位的特征。

目的探讨老年急性椎体脆性骨折患者的CT CT Hounsfield单位（HU）的特点。方法回顾性分析299例≥65岁的急性椎体脆性骨折的患者，其中77例患者的年龄和性别均与77例无骨折的对照患者相同。测量L1（L1-HU）的椎骨HU值，并在L1骨折的情况下使用T12和L2替代L1。结果299例老年患者共发生460例胸腰椎骨折，其中349例急性椎体脆性骨折和111例慢性骨折。平均L1-HU值为66.0±30.6 HU，在不同数量的椎体骨折患者中显示出显着差异（其中1处骨折：73.3±27.0 HU，2处骨折：58.7±32.5 HU，三个或三个以上骨折：40.7±28.8 HU；P <0.001）。对于1：1年龄和性别匹配的患者，77例骨折患者的L1-HU低于对照组（70.6±23.4 HU vs. 101.5±36.2 HU，P <0.001）。使用L1-HU区分骨折患者和对照组的受试者工作特征曲线下的面积为0.77（95％CI 0.70-0.85，P <0.001）。该临界值具有90％的高特异性或90％的高敏感性，分别可识别60 HU和100 HU骨折的患者。结论患有急性椎体脆性骨折的老年患者的HU值比没有骨折的老年人低得多。此外，椎骨HU值越低，患者发生一个以上椎骨骨折的可能性就越大。