Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, China.
Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medicine Sciences and Peking Union Medical College, Beijing, China.
J Clin Densitom. 2020 Jul-Sep;23(3):395-402. doi: 10.1016/j.jocd.2018.09.004. Epub 2018 Sep 15.
Bone mineral density measured by dual-energy X-ray absorptiometry (DXA) is the gold standard for diagnosis of osteoporosis. However, DXA interpretation can be influenced by analytic errors which can, in turn, interfere with diagnostic accuracy. One such source of potential error is the accurate identification of specific lumbar vertebrae on lumbar spine DXA images. Although the International Society for Clinical Densitometry has introduced several approaches to aid with this process, there remain individuals whose lumbar vertebrae cannot be labeled with certainty using these approaches. We designed the present study to systematically evaluate lumbar spine DXA images among a large cohort of Chinese patients and present an additional simple strategy for identifying L5 named the "em dash"-shaped L5 or "-"-shaped L5, based upon the two-dimensional relationship between the bilateral pedicles with the central spinous process on DXA images.
Lumbar spine posteroanterior DXA images from adult patients receiving care at a large tertiary hospital in Beijing, China from May to August 2016 were retrospectively reviewed. For each patient, data were collected regarding key anatomic features seen on DXA (positions of the most superior portions of the iliac crests, the lowest vertebra with ribs, and the longest transverse processes) and the proportion of patients presenting with "H"-shaped L4 and "-"-shaped L5. Chi-squared analyses were used to compare proportions across age strata.
DXA images from 1125 patients (79.6% female) were evaluated. The mean age of patients was 52.5 ± 14.8 yr (range: 19-90 yr). A horizontal line drawn across the superior-most portions of the iliac crests crossed the disk space between L4 and L5 among 78.3% of patients. The lowest ribs were most frequently (83.9%) observed at T12. Almost 80% of individuals had the longest transverse processes at L3. L4 was predominantly "H"-shaped (73.3%), however we found that the proportion of individuals with "H"-shaped L4 decreased steadily after 50 yr of age (p < 0.001). By contrast we observed that L5 was predominantly "-"-shaped (80.3%), with no significant differences in proportions across all age strata (p = 0.063).
The "-"-shaped L5 can be incorporated as an additional reference tool for lumbar spine DXA image analysis and may be particularly helpful for lumbar vertebrae identification among patients over 50 yr of age.
双能 X 射线吸收法（DXA）测量的骨密度是诊断骨质疏松症的金标准。然而，DXA 解读可能受到分析误差的影响，这反过来又会影响诊断的准确性。潜在误差的一个来源是在腰椎 DXA 图像上准确识别特定的腰椎。尽管国际临床密度测定学会已经提出了几种方法来辅助这一过程，但仍有一些人的腰椎无法使用这些方法确定。我们设计了本研究，对中国一个大型患者队列的腰椎 DXA 图像进行了系统评估，并提出了一种简单的附加策略，根据双侧椎弓根与 DXA 图像上中央棘突的二维关系，将 L5 标记为“破折号”形 L5 或“-”形 L5。
回顾性分析 2016 年 5 月至 8 月在中国北京一家大型三级医院接受治疗的成年患者的腰椎前后位 DXA 图像。对于每位患者，收集 DXA 上可见的关键解剖特征的数据（髂嵴最上部的位置、带肋骨的最低椎骨和最长的横突）以及呈现“H”形 L4 和“-”形 L5 的患者比例。卡方分析用于比较不同年龄组的比例。
评估了 1125 名患者（79.6%为女性）的 DXA 图像。患者的平均年龄为 52.5±14.8 岁（范围：19-90 岁）。一条穿过髂嵴最上部的水平线穿过 L4 和 L5 之间的椎间盘间隙，在 78.3%的患者中穿过。最低肋骨最常（83.9%）观察到 T12。几乎 80%的人最长的横突在 L3。L4 主要是“H”形（73.3%），然而，我们发现，50 岁以后，具有“H”形 L4 的个体比例稳步下降（p<0.001）。相比之下，我们观察到 L5 主要是“-”形（80.3%），在所有年龄组中，比例没有显著差异（p=0.063）。
“-”形 L5 可作为腰椎 DXA 图像分析的附加参考工具，对于 50 岁以上患者的腰椎识别特别有帮助。
