Lux Christopher J, Starke Jens, Rübel Jan, Stellzig Angelika, Komposch Gerda
Department of Orthodontics, University of Heidelberg, Heidelberg, Germany.
Cleft Palate Craniofac J. 2002 May;39(3):341-52. doi: 10.1597/1545-1569_2002_039_0341_voigrc_2.0.co_2.
An approach based on Euclidean distances between cephalometric landmarks is presented (1) to visualize and localize the individual shape changes of the complex craniofacial skeleton during growth and (2) to depict the individual dynamic behavior of developmental size and shape changes.
Growth-related craniofacial changes were investigated exemplarily for two male orthodontically untreated subjects from the Belfast Growth Study on the basis of lateral cephalograms at 7, 9, 11, 13, and 15 years. The interlandmark distances among seven skeletal cephalometric landmarks served as a database for the study. A modified Karhunen-Loève decomposition based on orthogonal modes and time-dependent scalar amplitudes was used to describe the growth process. The individual shape changes of the various craniofacial regions were visualized by allocation of colors to the respective distances, and overdrawn representations were reconstructed by means of multidimensional scaling.
This visualization technique allows anatomical regions to be characterized with respect to reduced or strengthened growth, compared with pure size changes. The clinically relevant mechanisms of craniofacial changes are visualized (e.g., shifts in the anteroposterior or vertical dimensions of the jaws in relation to cranial base and structural imbalances during development). In addition, overdrawing the effects of shape change on the skeletal structures gives a more readily comprehensible impression of the growth process. Taking account of the methodical limitations of this approach (e.g., the restrictions concerning the number of landmarks), the clinician may take advantage of this technique in orthodontic or surgical diagnostics to gain additional insight into the individual complex size and shape changes during development along with their dynamic behavior.
提出一种基于头影测量标志点之间欧几里得距离的方法，（1）用于可视化和定位复杂颅面骨骼在生长过程中的个体形状变化，以及（2）描绘发育过程中大小和形状变化的个体动态行为。
基于贝尔法斯特生长研究中两名未经正畸治疗的男性受试者在7、9、11、13和15岁时的头颅侧位片，对与生长相关的颅面变化进行了示例性研究。七个骨骼头影测量标志点之间的标志点间距作为该研究的数据库。使用基于正交模式和随时间变化的标量幅度的改进型卡尔胡宁 - 洛伊夫分解来描述生长过程。通过为各个距离分配颜色来可视化不同颅面区域的个体形状变化，并借助多维缩放重建叠加表示。
与单纯的大小变化相比，这种可视化技术能够根据生长减弱或增强来表征解剖区域。颅面变化的临床相关机制得以可视化（例如，颌骨相对于颅底的前后或垂直维度的移位以及发育过程中的结构失衡）。此外，叠加形状变化对骨骼结构的影响能更直观地呈现生长过程。考虑到该方法的方法学局限性（例如，关于标志点数量的限制），临床医生在正畸或外科诊断中可利用此技术，以深入了解个体在发育过程中复杂的大小和形状变化及其动态行为。
