多平面重建在CT眼内金属异物测量和定位中的应用

The Application of CT Multiplanar Reconstruction to the Measuring and Localizing of Intraocular Metal Foreign Bodies

目的 探讨 CT多平面重建 (MPR)在眼内金属异物测量和定位中的应用。材料与方法 48枚眼内金属异物 ,在横断面上分别于软组织窗和骨窗下进行异物最大径的测量 ;异物在冠状面上的高度分别采用异物两端所在平面床的位置之差和在冠状面或矢状面重建图像上直接测量。将上述结果分别进行比较 ,并与手术所取出异物的测量值比较。将 MPR和传统的坐标定位图 2种定位结果与手术结果进行比较。结果 骨窗和软组织窗下异物大小的测量值有显著性差异 ,在冠状面或矢状面 MPR图像上直接测量异物的高度和异物两端所在平面床的位置之差有显著性差异 ,骨窗下异物的测量值与标本测量值无显著性差异。MPR在观察异物的形态、测量其大小和定位方面较坐标图准确和直观。结论 对眼内金属异物大小的测量应以骨窗为准 ,并适时进行

Objective To evaluate multiplanar reconstruction (MPR) in measuring and localizing of intraocular metal foreign bodies.Materials and Methods Forty two patients, aged 6~50 years, were included in thie study. Forty eight intraocular metal foreign bodies were found in 42 eyes. (1) The largest size of the foreign bodies was measured on bone window (L 500～800, W 1800～2800) and soft tissue window (L 40～50, W 200～250), respectively. (2) The largest size of the foreign body measured on bone window was compared with its actual size obtained from the sample after operation. (3) The size of the foreign body on the coronal plane was obtained by two methods: ① direct measurement of coronal or sagittal MPR, and ② the difference between the two table positions where the two tips of the foreign body were displayed separately. Comparison of the above measurements with the surgical results was made.Results The differences in (1) and (3) were statistically significant, while no significant difference was seen in (2). MPR was superior to coordinate setting in correctly observing, measuring and localizing the foreign body.Conclusion In measuring the size of intraocular metal foreign body, bone window should be used, and MPR is very important for the localization of foreign body.