Hoyt Benjamin W, Lundy Alex E, Clark DesRaj M, Colantonio Donald, Tintle Scott M, Potter Benjamin K
Department of Surgery, Orthopaedics, USU-Walter Reed National Military Medical Center, Bethesda, MD.
J Orthop Trauma. 2021 May 1;35(5):e158-e164. doi: 10.1097/BOT.0000000000001980.
To correlate femoral neck Hounsfield units (HUs) measured on a computed tomography (CT) scan to dual-energy x-ray absorptiometry (DEXA) T-scores allowing evaluation of bone mineral density (BMD) over time after lower extremity trauma-related amputation.
Retrospective cohort study.
United States military trauma referral center.
Military combat-related lower extremity amputees with both DEXA and CT scans within 6 months of each other.
None.
Correlation between femoral neck comprehensive mean HUs and BMD and HUs threshold for low BMD.
Regression model correlation (r) between CT HU and DEXA T-score was r = 0.84 [95% confidence interval (CI) 0.52-0.94] and r = 0.81 (95% CI 0.57-0.92) when CT imaging was separated from DEXA by less than 4 and 5 months, respectively. Beyond 5 months separation, correlation decreased to r = 0.60 (95% CI 0.29-0.80). Using a receiver operator characteristic curve for mean comprehensive HUs to determine low BMD with 4-month cut-off, a threshold of 151 HUs was 97% sensitive and 84% specific to identify low BMD, whereas 98 HUs was 100% sensitive and 100% specific to identify osteoporosis.
Using opportunistic CT, clinicians can reliably estimate BMD in trauma-related amputees. This information will inform providers making decisions regarding weightbearing and bisphosphonate therapy to limit further loss. Future phases of this study will aim to use this correlation to study the effects of weightbearing advancement timing, bisphosphonate therapy, and interventions on the natural history of bone density after amputation.
Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
将计算机断层扫描（CT）上测得的股骨颈亨氏单位（HU）与双能X线吸收法（DEXA）T值相关联，以便评估下肢创伤相关截肢术后随时间变化的骨密度（BMD）。
回顾性队列研究。
美国军事创伤转诊中心。
在彼此6个月内同时进行DEXA和CT扫描的与军事战斗相关的下肢截肢者。
无。
股骨颈综合平均HU与BMD之间的相关性以及低BMD的HU阈值。
当CT成像与DEXA的间隔分别小于4个月和5个月时，CT HU与DEXA T值之间的回归模型相关性（r）分别为r = 0.84 [95%置信区间（CI）0.52 - 0.94]和r = 0.81（95% CI 0.57 - 0.92）。间隔超过5个月时，相关性降至r = 0.60（95% CI 0.29 - 0.80）。使用受试者工作特征曲线，以平均综合HU确定4个月截断值时的低BMD，151 HU的阈值识别低BMD的敏感度为97%，特异度为84%，而98 HU识别骨质疏松的敏感度和特异度均为100%。
利用机会性CT，临床医生可以可靠地估计创伤相关截肢者的BMD。这些信息将为医疗服务提供者在做出关于负重和双膦酸盐治疗的决策时提供参考，以限制进一步的骨质流失。本研究的后续阶段旨在利用这种相关性来研究负重进展时机、双膦酸盐治疗以及干预措施对截肢后骨密度自然病程的影响。
诊断性IV级。有关证据水平完整描述，请参阅《作者须知》。
