下颌髁突脱位骨折后颞下颌关节软组织改变的MRI表现

目的 分析下颌髁突脱位骨折后颞下颌关节(TMJ)软组织改变的MRI表现.方法 应用矢状面和冠状面质子密度加权成像(PDWI)和T2WI连续检查103侧(77例)患有下颌髁突脱位骨折的颞下颌关节(TMJ).结果 MRI上,103侧髁突脱位骨折后的TMJ异常表现有:(1)髁突骨折断片向前下(102侧,99.0%)和前(1侧,10%)脱位;(2)关节盘移位(100侧,97.1%),其中矢状面MRI显示关节盘随脱位的髁突向前下移位者99侧,向前移位者1侧;(3)关节腔积液(103侧,100%);(4)关节盘后区信号异常(91侧,88.3%);(5)关节盘下后附着异常(89侧,86.4%);(6)关节囊异常(89侧,86.4%);(7)关节盘上后附着异常(37侧,35.9%);(8)关节盘变形(8侧,7.8%);(9)关节盘撕裂(8侧,7.8%);(10)颞骨关节窝骨折(4侧,3.9%).结论矢状面MRI上,多数下颌髁突脱位骨折以TMJ关节盘随脱位的髁突向前下移位,并伴有关节腔积液为特点.

MRI findings of soft tissue damages involving the temporomandibular joint after dislocated condylar fracture

Objective To document MRI findings of soft tissue damages involwing the temporomandibular joint (TMJ) after dislocated condylar fracture. Methods Seventy-seven subjects (103 TMJs), who suffered from the dislocated condylar fractures, underwent both sagittal and coronal MR imaging including proton density-weighted image ( PDWI ) and TzWI.Results On MR images, the TMJ structural changes after dislocated condylar fractures included : ( 1 ) displacement of the dislocated fragment in the anterior-inferior direction ( 102 TMJs, 99.0% ) and in the anterior direction ( 1 TMJ, 1.0% ) ; (2)disc displacement (100 TMJs, 97.1% ) in the anterior-inferior direction (99 TMJs) and in the anterior direction (1 TMJ) along with the dislocated condylar fragments on sagittal MR images; (3) joint effusion (103 TMJs, 100%);(4) abnormal signal intensity in the retrodiskal tissues of the TMJ ( 91 TMJs ,88.3% ) ; (5) abnormal changes of inferior posterior attachments of disc ( 89 TMJs, 86.4% ) ; ( 6 )abnormal changes of joint capsule ( 89 TMJs, 86.4% ) ; ( 7 ) abnormal changes of superior posterior attachments of disc ( 37 TMJs, 35.9% ) ; ( 8 ) disc deformation ( 8 TMJs, 7.8% ) ; ( 9 ) disc avulsion (8 TMJs, 7.8% ) and ( 10 ) glenoid fossa fractures (4 TMJs, 3.9% ). Conclusion On sagittal MR images, the TMJ soft tissue changes after dislocated condylar fracture were mainly presented as the disc displacement in the same direction (anterior-inferior direction) as the dislocation of the fractured fragments,usually in association with joint effusion.