Rheumatology department, University Hospital of Nancy, 5 rue du Morvan, 54500, Vandœuvre-Lès-Nancy, France.
Inserm, CIC-1433 Clinical Epidemiology, University Hospital of Nancy, Nancy, France.
Osteoporos Int. 2019 Jun;30(6):1215-1222. doi: 10.1007/s00198-019-04931-w. Epub 2019 Mar 13.
Screening for osteoporosis is crucial in rheumatoid arthritis (RA) patients. The aim of this study was to assess the value of thoraco-abdomino-pelvic CT-derived bone mineral density (BMD) results in L1, compared to dual energy X-ray absorptiometry (DXA) results for osteoporosis screening in rheumatoid arthritis patients.
Consecutive RA patients who underwent a CT-scan and DXA within a 2-year period were retrospectively included. The CT sagittal images were then evaluated for vertebral fractures from T4 to L5 using the Genant classification. The CT-attenuation values (in Hounsfield units (HU)) of trabecular bone in L1 were measured on axial images and compared to the DXA results.
This study included 105 patients (mean age 61.1 years (± 9.5), 78.1% women). There were 28 patients (26.7%) with DXA-defined osteoporosis and 32 (30%) with osteoporotic fractures (vertebral and/or non-vertebral). The CT assessment indicated that the mean (SD) vertebral L1 attenuation was 142.2 HU (± 18.5). The diagnostic performance for the vertebral CT-attenuation measurement was acceptable: the AUC was 0.67 for predicting osteoporotic fractures and of 0.69 for predicting vertebral fractures. Among patients with osteoporotic fractures, there were 23 (74%) patients categorized as osteoporotic with a L1 CT-attenuation of 135 HU or less, whereas there were only 13 patients (42%) identified by DXA.
CT offers a combined opportunistic screening for osteoporosis by assessing both vertebral fractures and bone density on routine CT-scans. This approach may be particularly interesting for RA patients with a high osteoporosis risk.
在类风湿关节炎（RA）患者中，骨质疏松症的筛查至关重要。本研究旨在评估与双能 X 射线吸收法（DXA）相比，基于 CT 测量的腰椎（L1）骨密度（BMD）结果在 RA 患者骨质疏松症筛查中的价值。
回顾性纳入了在 2 年内同时接受 CT 扫描和 DXA 检查的连续 RA 患者。使用 Genant 分类法对 CT 矢状图像进行 T4 到 L5 椎体骨折评估。在轴向图像上测量 L1 松质骨的 CT 衰减值（以亨氏单位（HU）表示），并与 DXA 结果进行比较。
本研究纳入了 105 例患者（平均年龄 61.1±9.5 岁，78.1%为女性）。28 例（26.7%）患者被 DXA 定义为骨质疏松症，32 例（30%）患者存在骨质疏松性骨折（椎体和/或非椎体）。CT 评估表明，L1 椎体平均（SD）衰减值为 142.2 HU（±18.5）。椎体 CT 衰减值测量的诊断性能尚可：预测骨质疏松性骨折的 AUC 为 0.67，预测椎体骨折的 AUC 为 0.69。在骨质疏松性骨折患者中，有 23 例（74%）患者的 L1 CT 衰减值为 135 HU 或更低，被归类为骨质疏松症，而 DXA 仅识别出 13 例（42%）患者。
CT 可在常规 CT 扫描中同时评估椎体骨折和骨密度，为骨质疏松症提供一种联合的机会性筛查方法。对于骨质疏松风险较高的 RA 患者，这种方法可能特别有趣。
