Department of Orthopaedic Surgery, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
Eur J Radiol. 2011 Dec;80(3):805-10. doi: 10.1016/j.ejrad.2010.10.016. Epub 2010 Nov 11.
To retrospectively assess the diagnostic sensitivity of 45° Dunn view and cross-table lateral radiographs for the assessment of cam deformity by comparison with radial MRI.
60 cases with radiographs (38 a-p and 45° Dunn views, 22 a-p and cross-table lateral views) and radial MRI were assessed. Alpha angle measurements were obtained both for radiographs and radial MRI. Statistics included frequency analysis, bivariate linear correlation analyses of MRI and radiograph measurements and cross-table analyses testing for the sensitivity and specificity of radiographs for the detection of an alpha angle larger than 55°.
53.3% had the maximum alpha angle in the superior-anterior aspect of the femoral head-neck junction. Cam deformity was found in 45/60 cases (75%) in radial MRI. Pearson correlation demonstrated the Dunn view was most accurate for the superior-anterior aspect (.772, P<.001). The cross-table lateral views were best suited for the anterior-superior aspect (.511, P<.05). The sensitivity for cam deformity in the Dunn view was 96.4% vs. 70.6% in the cross-table lateral view.
The 45° Dunn view can improve the first line of impingement diagnostics. Radial MRI however remains indispensable for pre-operative planning and the evaluation of symptomatic cases without obvious deformity.
通过与 MRI 对比，回顾性评估 45°Dunn 视图和交叉桌上侧位片对凸轮畸形的诊断灵敏度。
对 60 例患者的影像学资料（38 张前后位片和 45°Dunn 视图，22 张前后位片和交叉桌上侧位片）和 MRI 进行评估。对前后位片和 MRI 均进行 Alpha 角测量。统计学分析包括频率分析、MRI 和 X 线片测量的双变量线性相关分析，以及用于检测 Alpha 角大于 55°的 X 线片的敏感性和特异性的交叉表分析。
53.3%的患者在股骨头颈交界处的前上部位有最大的 Alpha 角。在 60 例患者中，45 例（75%）在 MRI 上发现凸轮畸形。Pearson 相关分析显示，Dunn 视图在前上方面最准确（.772，P<.001）。交叉桌上侧位片最适合前上方面（.511，P<.05）。在 Dunn 视图中，凸轮畸形的敏感性为 96.4%，而在交叉桌上侧位片的敏感性为 70.6%。
45°Dunn 视图可改善撞击症的一线诊断。然而，MRI 对于术前计划和评估无明显畸形的症状性病例仍然是不可或缺的。
