三维CT成像在小儿寰枢椎旋转性移位中的应用

Clinical Application of 3D CT in Atlanto-axial Rotatory Displacement in Children

目的 探讨三维CT成像 ( 3DCT)对小儿寰枢椎旋转性移位 (atlanto axialrotatorydisplacement,AARD)的诊断价值。材料与方法 分析和比较 6例小儿AARD在普通CT扫描 ( 2DCT)和 3DCT中的影像表现。结果 ( 1) 2DCT和 3DCT测量 6例患儿寰齿前间距和齿状突侧距的结果基本相同 ;( 2 ) 3DCT显示 6例患儿侧块均有不同程度的移位和旋转 ,2DCT不能显示侧块有无移位和旋转 ;( 3) 6例中 ,2DCT显示 1例同时有寰椎 (C1)和枢椎 (C2 )的异常旋转 (分别为 8°和 35°) ,3例有C2 异常旋转 ( 7°～ 30° ,平均 18.7°) ,2例未发现寰枢椎的旋转异常。 3DCT显示 2例同时有C1和C2 旋转异常 (分别为 11°、30°和 11°、40°) ,4例有C2 旋转异常 ( 9°～ 34° ,平均 16 .5°)。相同病例 ,2DCT对C1和C2 旋转程度的测量低于 3DCT所测得的结果 ;( 4 ) 3DCT发现 1例齿状突发育不良 ,表现为齿状突短平和齿突尖消失 ,2DCT不能观察齿状突的发育状况。结论 3DCT对AARD的诊断作用明显优于 2DCT。 3DCT不仅能准确地、直观地评估齿状突和侧块的移位程度、方向以及寰枢椎的旋转程度 ,而且能发现伴发的寰枢椎尤其是齿状突发育畸形 。

Objective To evaluate 3D CT reconstruction in diagnosing atlanto axial rotatory displacement (AARD) in children.Materials and Methods Imaging findings of AARD on 2D CT and 3D CT in 6 children were analyzed and compared with each other.Results (1) The anterior atlanto odontoid distance and the distance between odontoid process and lateral mass of the atlas on 2D CT and 3D CT were the same. (2) 3D CT clearly revealed displacement of lateral mass in 6 cases, while 2D CT couldn't. (3) On 2D CT, abnormal rotation of C 1 (8°) and C 2 (35°) was seen in one case, abnormal rotation of C 2 (7°～30°, mean 18.7°). On 3D CT, abnormal rotation of C 1, C 2 was seen in 2 cases, with the rotating angel of 11°, 30° and 11°, 40°, respectively. Abnormal rotation of C 2 was seen in 4 cases (9°～34°, mean 16.5°). The rotation angle of C 1, C 2 measured on 2D CT was lower than that measured on 3D CT in same patient. (4) Hypoplasia of the odontoid process, which presented as shortened process and absence of apex, was found in one case on 3D CT, while these changes couldn't be demonstrated on 2D CT.Conclusion 3D CT is superior to 2D CT in diagnosing AARD. 3D CT can not only accurately and directly evaluate the severity, direction of the displacement of the odontoid process and lateral mass, but also can reveal the developing malformation of C 1 and C 2, therefore, 3D CT has great value in diagnosing AARD and in guiding its management.