Development of Automatic Three-dimensional Reconstruction System of Temporomandibular Joint Using Magnetic Resonance Images

颞下颌关节(TMJ)诊断系统是新近发展起来的一种能够从磁共振图像中自动检测出髁突和关节窝骨表面的诊断系统。该系统还可以直观地评价解剖构件的三维形态及其空间关系。骨骼表面检测的过程包括利用活动轮廓模型(Snake)从序列图像中检测轮廓，以及利用活动轮廓模型的三维扩展来检测表面。操作员输入一个穿过TMJ中心的横截面得到初始模型，然后由相邻的横截面自动检测其他横截面，完成轮廓检测。检测到的骨表面代表了它们的解剖特征，三维上是光滑的。通过将该方法的结果与…的结果进行比较，验证了该方法检测轮廓的有效性对髁状突和关节窝进行三维重建，在任意横断面上显示其断层图像，并对髁状突与关节窝之间的距离进行假彩色分级。为了评价该方法的有效性，使用了一例患者(45岁女性)的双侧TMJ的MRI图像，该患者右侧TMJ疼痛，并被诊断为关节盘前移位而无复位。结果：三维重建图像可识别出患侧的骨赘和扁平化，通过对髁状突至关节窝距离的伪彩色分级，可发现患侧关节间隙严重狭窄。结论：该系统在临床上具有临床应用价值，可用于自动检测和直观评价髁状突和关节窝的三维形态及其空间关系。较少

Temporomandibular joint (TMJ) diagnostic system which enables to automatically detect the bone surface of condyle and articular fossa from magnetic resonance (MR) images was newly developed. This system also made it possible to visually evaluate the three-dimensional form of the anatomical components and their spatial relationships.The process of detecting the bone surface consisted of detecting the contour from serial images by active contour model (Snakes) and detecting the surface by active surface model which was the three-dimensional extension of the active contour model. One cross-section through the center of TMJ was input by an operator to gain the initial model and then other cross-sections were automatically detected by the adjacent sections in which detecting contour was completed. Detected bone surfaces represented their anatomical feature and were three-dimensionally smooth. The validity of the detected contour was confirmed by comparing the results of this method and the … More manual trace by dentists.Three-dimensional reconstruction of the condyle and articular fossa, presentation of their tomogram in random cross-sections, and pseudo color grading of the distance between condyle and articular fossa on the condylar surface were performed. To evaluate the validity of this method, MR images of bilateral TMJs in a patient (45 year-female) who had pain in the right side TMJ and was diagnosed Temporomandibular Disorders with anterior disc displacement without reduction were used. As a result, osteophyte and flattening in the symptomatic side were recognized by the image of the three-dimensional reconstruction and heavily narrow articular space was found by the pseudo color grading of the distance between condyle and articular fossa on the condylar surface.In conclusion, this system was clinically valuable in automatic detection of the bone surfaces of condyle and articular fossa and in visual evaluation of three-dimensional form of condyle and articular fossa, and their spatial relationship. Less