间接性TMJ损伤的MRI表现及意义

MRI findings of the TMJ after indirect trauma:A study on MRI diagnosis of the traumatic temporomandibular joints

目的：研究间接性颞下颌关节损伤的MRI表现及其在颞下颌关节病诊断中的意义。方法：用多功能生物撞击机以10MPa的气压推动撞击杆,使0.845kg的钢质圆柱形抛射体以（18.46±0.31）m/s的撞击速度在开口状态下撞击山羊颏部,撞击能量为139.2-148.8J,间接造成幼年山羊双侧颞下颌关节的间接性损伤,分别于3h、7d、2周、1月及3月行MRI检查,采用斜矢状闭、开口位梯度回波T1W/3D/WATS、自旋回波PDW/TSE、T1W/SE和T2W/TSE序列及冠状闭口位T1W/3D/WATS、PDW/TSE扫描观察TMJ结构变化,并进行组织学观察。结果：通过组织学观察可见间接性创伤可导致幼年山羊TMJ损伤,早期表现为髁突表面软骨碎裂,关节盘挫裂和移位,关节间隙减小及关节腔内有出血,损伤后期可见髁突表面软骨破坏,关节盘畸形,关节间隙减小。MRI可较清楚的显示上述改变。结论：间接性颞下颌关节损伤可导致幼年山羊TMJ软、硬组织结构和形态的变化,MRI能全面地观察TMJ损伤后组织改变,对颞下颌关节损伤的诊断有重要价值。

Objective：To discuss the diagnosis value of MRI for observing the structure changes in temporomandibular joints after trauma. Methods：The multi-functional impact system was used in the study. The temporomandibular joints of both sides were all indirectly injured. With the goats＇ mouth open, the injury was induced at the chin. The velocity of the cylindrical projectile（ weight 0.845 kg） was （ 18.46 ±0.31 ） m/s, and the impact energy was 139.2 148.8 J. The goats were examined with MRI in 3 h, 7 d, 2 weeks, 1 month and 3 months after trauma of TMJs. Oblique sagittal of open mouth were performed with T1W/3D/WATS, PDW/TSE, T1W/SE, T2W/TSE sequences and coronal of close mouth with Tt W/3D/WATS, PDW/TSE sequences. All specimens were checked by histological method. Results：By histological examination and MRI, the condylar articular surface was partially lost, and the discs were displaced and ruptured in the early post-trauma stage. The surface of condyles was eroded and eburnated, and the discs were deformed. Conclusion ： MRI can be used to investigate the hard and soft tissue injuries of the tempomandibular joint. It is very useful in diagnosis of the traumatic temporomandibular joints.