Improvement of Three-dimensional Standardization Using Oblique Cephalograms and Application to Diagnosis of Mandibular Displacement

作者发展了一种扫描X光照片并对其图像进行处理的方法，以从斜位头影重建颌面部结构的三维标志，以进行高精度的定量测量。开发和改进扫描仪输入的三维坐标重建(1)在干燥颅骨的每个标志物上附着一个铅球，并在每个侧面填充根管充填剂，然后使用图像扫描仪扫描颅骨的斜位(45°左右)、正位和侧位片，生成图像文件，通过图像分析软件对扫描图像进行过滤，手动识别牙齿、颅骨和上下颌骨的标志物。(2)通过三维计算程序对标志物进行水平检测、原点迁移和三维坐标计算。由于每个测量点识别的难度和误差不同，…根据所用胶片的类型，每个地标的权重分别设置为四种类型的照片，并用于三维坐标计算。(3)三维显示程序允许通过垂直旋转(±90°)、水平旋转(±180°)和垂直或水平方向的平行平移从不同角度自由显示计算出的三维坐标值。显示图像也可以从0.62放大或缩小到1.61。为了在手术前和手术后进行比较，两个三维坐标文件可以重叠的形式同时显示。(4)即使是难以从倾斜(45°左右)头颅侧位片中识别的标志物，也可以通过正位和侧位片准确识别。此外，横向坐标转换将允许使用传统的横向头颅侧位图进行三维分析。应用于下颌骨不对称的诊断上述方法将提高上颌骨不对称的三维显示和直线或角度测量的精度，为诊断和治疗计划提供有效的工具。较少

The authors have developed a method of scanning X-ray photographs and processing their images to reconstruct three-dimensional landmarks in a maxillofacial sttucture from oblique cephalograms for high-precision quantitative measurements.1. Developing and Improving Three-dimensional Coordinate Reconstniction by Scanner Input(1)A lead ball was attached to each landmark in a dry skull and each lateral was filled with a root canal filling agent Then oblique (45°right and left), frontal, and lateral cephalograms of the skull were scanned to produce image files using an image scanner After filtering the scanned images using image analysis software, the landmarks at the teeth, skull, and upper and lower maxillary bones were identified manually.(2)The landmarks were processed in order of horizontal detection, origin migration, and three-dimensional coordinate calculation using a three-dimensional calculation program. Since the difficulty and error of identification at each measuring point diff … More er depending on the type of film used, weighting at each landmark was set individually for the four types of photographs and used for the three-dimensional coordinate calculations.(3)A three-dimensional display program permits free display of the calculated three-dimensional coordinate values from different angles by vertical rotation(±90°), horizontal rotaton(±180°), and parallel translation in the vertical or horizontal direction. The display image can also be enlarged or reduced from 0.62 to 1.61. For comparison before and alter an operation, two three-dimensional coordinate files can be displayed simultaneously in an overlapping form.(4)Even landmarks difficult to identify from oblique (45°right and left) cephalograms can be identified accurately using frontal, and lateral cephalograms. In addition, lateral coordinate conversion will allow three-dimensional analysis with conventional lateral cephalograms.2. Application to the Diagnosis of Asymmetric Lower MaxillaThe above method will improve the precision of three-dimensional display and linear or angular measurement in actual cases of asymmetric maxilla and serve as an efficient tool for diagnosis and therapeutic planning. Less