Wagner Scott C, Dworak Theodora C, Grimm Patrick D, Balazs George C, Tintle Scott M
1Department of Orthopaedics, Walter Reed National Military Medical Center, Bethesda, Maryland 2Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, Maryland 3Department of Orthopaedic Surgery, University of Pennsylvania Health System, Philadelphia, Pennsylvania.
J Bone Joint Surg Am. 2017 Apr 19;99(8):e38. doi: 10.2106/JBJS.15.01244.
Hounsfield unit (HU) measurement obtained from computed tomography (CT) scans of the wrist is a potential new screening method for low bone mineral density (BMD). We hypothesized that HU measurements of the ulnar head obtained from CT scans would correlate with BMD assessed with dual x-ray absorptiometry (DXA) scans of the forearm.
Patients with both upper-extremity CT and DXA scans performed at a single institution were included in the study. Hounsfield units were manually measured in the distal part of the ulna by 1 author blinded to the DXA results. Average values were then compared with forearm BMD values as determined with a DXA scan.
Seventy-seven CT scans of 74 patients were included. Average HU values were significantly lower in the osteoporotic and osteopenic groups in comparison with the normal BMD group. The upper limit of the 95% confidence interval for osteopenic patients was 145.9 HU. The average forearm T-score for patients with an HU value at or below the cutoff of 146 was significantly lower than the average T-score for those with an HU value of >146 HU (p < 0.0001). Sensitivity and negative predictive value for low BMD using this cutoff value were calculated to be 91% and 89%, respectively.
Distal ulnar HU measurements accurately reflect the BMD of the forearm as diagnosed with a DXA scan. Our results suggest that distal ulnar HU measurements of ≤146 HU are strongly associated with low BMD and that values above this cutoff accurately rule out low forearm BMD with a high degree of sensitivity and negative predictive value. Utilizing this technique may improve the capture of at-risk patients and streamline the screening process for osteoporosis.
Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.
通过腕部计算机断层扫描（CT）获得的亨氏单位（HU）测量值是一种用于筛查低骨密度（BMD）的潜在新方法。我们假设，从CT扫描获得的尺骨头HU测量值将与通过双能X线吸收法（DXA）扫描评估的前臂骨密度相关。
本研究纳入了在同一机构进行了上肢CT和DXA扫描的患者。由一名对DXA结果不知情的作者在尺骨远端手动测量亨氏单位。然后将平均值与DXA扫描确定的前臂骨密度值进行比较。
纳入了74例患者的77次CT扫描。与正常骨密度组相比，骨质疏松组和骨量减少组的平均HU值显著更低。骨量减少患者的95%置信区间上限为145.9 HU。HU值等于或低于146这个临界值的患者的平均前臂T值显著低于HU值>146 HU的患者的平均T值（p < 0.0001）。使用这个临界值计算出的低骨密度的敏感性和阴性预测值分别为91%和89%。
尺骨远端的HU测量值准确反映了通过DXA扫描诊断的前臂骨密度。我们的结果表明，尺骨远端HU测量值≤146 HU与低骨密度密切相关，而高于这个临界值的值能以高度的敏感性和阴性预测值准确排除低前臂骨密度。利用这项技术可能会改善对高危患者的筛查，并简化骨质疏松症的筛查流程。
诊断性III级。有关证据水平的完整描述，请参阅作者指南。
