Jacobsen Petra A, Becker Devra, Govier Daniel P, Krantz Steven G, Kane Alex
Washington University School of Medicine, St. Louis, Missouri, USA.
Cleft Palate Craniofac J. 2009 Sep;46(5):487-93. doi: 10.1597/06-194.1. Epub 2008 Apr 11.
The purpose of this research was to develop a novel quantitative method of describing calvarial shape by using ellipsoid geometry. The pilot application of Ellipsoid Analysis was to compare calvarial form among individuals with untreated unilateral coronal synostosis, metopic synostosis, and sagittal synostosis and normal subjects.
The frontal, parietal, and occipital bones of 10 preoperative patients for each of the four study groups were bilaterally segmented into six regions using three-dimensional skull reconstructions generated by ANALYZE imaging software from high-resolution computed tomography scans. Points along each segment were extracted and manipulated using a MATLAB-based program. The points were fit to the least-squares nearest ellipsoid. Relationships between the six resultant right and left frontal, parietal, and occipital ellipsoidal centroids (FR, FL, PR, PL, OR, and OL, respectively) were tested for association with a synostotic group.
Results from the pilot study showed meaningful differences between length ratio, angular, and centroid distance relationships among synostotic groups. The most substantial difference was exhibited in the centroid distance PL-PR between patients with sagittal synostosis and metopic synostosis. The measures most commonly significant were centroid distances FL-PR and FL-PL and the angle OR-FR-PR. Derived centroid relationships were reproducible.
Ellipsoid Analysis may offer a more refined approach to quantitative analysis of cranial shape. Symmetric and asymmetric forms can be compared directly. Relevant shape information between traditional landmarks is characterized. These techniques may have wider applicability in quantifying craniofacial morphology with increase in both specificity and general applicability over current methods.
本研究的目的是开发一种利用椭球体几何形状来描述颅骨形状的新型定量方法。椭球体分析的初步应用是比较未经治疗的单侧冠状缝早闭、额缝早闭、矢状缝早闭患者与正常受试者之间的颅骨形态。
使用ANALYZE成像软件从高分辨率计算机断层扫描生成的三维颅骨重建，将四个研究组中每组10名术前患者的额骨、顶骨和枕骨双侧分割为六个区域。使用基于MATLAB的程序提取并处理每个节段上的点。将这些点拟合到最小二乘最近椭球体。测试六个所得的左右额、顶和枕椭球体质心（分别为FR、FL、PR、PL、OR和OL）之间的关系与缝早闭组的相关性。
初步研究结果显示，缝早闭组之间在长度比、角度和质心距离关系方面存在有意义的差异。矢状缝早闭和额缝早闭患者之间质心距离PL - PR的差异最为显著。最常具有显著性的测量指标是质心距离FL - PR和FL - PL以及角度OR - FR - PR。得出的质心关系具有可重复性。
椭球体分析可能为颅骨形状的定量分析提供一种更精细的方法。可以直接比较对称和不对称形式。表征了传统地标之间的相关形状信息。这些技术在量化颅面形态方面可能具有更广泛的适用性，与当前方法相比，特异性和普遍适用性均有所提高。
