Szulc P, Munoz F, Sornay-Rendu E, Paris E, Souhami E, Zanchetta J, Bagur A, van der Mooren M J, Young S, Delmas P D
INSERM Research Unit 403, Hôpital Edouard Herriot, Lyon, France.
Bone. 2000 Dec;27(6):841-6. doi: 10.1016/s8756-3282(00)00398-7.
The semiquantitative assessment of vertebral deformities is based on visual evaluation. The quantitative approach is based on different morphometric criteria. This study is aimed at comparing the impact of different reference groups to define normal vertebral shape on the diagnosis of verterbral deformities. Reference normal values were obtained in three groups of women: French, mixed European, and Argentinian. All these women had normal lumbar spine bone mineral density and no vertebral deformities according to the semiquantitative assessment. In a group of 135 women having vertebral deformities according to Genant's semiquantitative assessment, three different morphometric criteria were applied. Morphometric diagnosis disclosed a good agreement with semiquantitative assessment. Agreement of diagnosis was higher for a given cutoff using thresholds obtained in different reference groups (kappa = 0.84-0.96) and lower when different criteria were compared using thresholds obtained in the same reference group (kappa = 0. 75-0.85). When fracture thresholds obtained in three different cohorts were compared separately for the three morphometric criteria, agreement was the highest when the cutoff was based only on the arithmetical mean of vertebral heights and was independent of its standard deviation (SD). Average vertebral height ratios did not differ between the three reference cohorts, whereas SDs of vertebral height ratios were the highest in the mixed European cohort and the lowest in the French cohort (F = 7.41, p < 0.001). In the three groups of women of different nationality, SDs of vertebral height ratios, but not the arithmetical means, were significantly higher in the radiographs of poor quality compared with those of good quality. Thus, the main source of difference of diagnosis was related to different SDs whereas average height ratios were not different. Differences in SDs between the three groups were found to be related, at least partly, to poor quality of radiographs. The impact of the differences between populations seems less important, however, only three countries were compared. These findings suggest that those techniques that take into account the SD of vertebral height ratios will provide different reference values for vertebral morphometry. Because differences in SDs depend mainly on the quality of radiographs, they can be reduced by improving the X-ray technique and by the use of standardized protocols. This variability will result in the identification of a variable number of vertebral deformities in osteoporotic women. These results may be of importance especially for multicentric studies.
椎体畸形的半定量评估基于视觉评估。定量方法则基于不同的形态计量学标准。本研究旨在比较不同参照组对定义正常椎体形态的影响，以及其对椎体畸形诊断的作用。在三组女性中获取了参照正常值：法国女性组、欧洲混合组和阿根廷女性组。根据半定量评估，所有这些女性的腰椎骨密度均正常且无椎体畸形。在一组根据Genant半定量评估患有椎体畸形的135名女性中，应用了三种不同的形态计量学标准。形态计量学诊断与半定量评估显示出良好的一致性。对于使用不同参照组获得的阈值，在给定截断值时诊断的一致性较高（kappa = 0.84 - 0.96）；而当使用同一参照组获得的阈值比较不同标准时，一致性较低（kappa = 0.75 - 0.85）。当分别针对三种形态计量学标准比较在三个不同队列中获得的骨折阈值时，当截断值仅基于椎体高度的算术平均值且与其标准差（SD）无关时，一致性最高。三个参照队列之间的平均椎体高度比值无差异，而椎体高度比值的标准差在欧洲混合队列中最高，在法国队列中最低（F = 7.41，p < 0.001）。在不同国籍的三组女性中，与质量良好的X线片相比，质量较差的X线片中椎体高度比值的标准差显著更高，但算术平均值无差异。因此，诊断差异的主要来源与不同的标准差有关，而平均高度比值并无差异。发现三组之间标准差的差异至少部分与X线片质量差有关。然而，由于仅比较了三个国家，人群之间差异的影响似乎不太重要。这些发现表明，那些考虑椎体高度比值标准差的技术将为椎体形态测量提供不同的参考值。由于标准差的差异主要取决于X线片的质量，可通过改进X线技术和使用标准化方案来降低。这种变异性将导致在骨质疏松女性中识别出数量可变的椎体畸形。这些结果可能对多中心研究尤为重要。
