摘要
目的:探讨镍铬合金修复体对磁共振检查的安全性及准确性的影响。方法:为猴右侧上颌侧切牙制作、配戴镍铬合金铸造冠,用 2.0T Prestige MR扫描仪按临床常规进行5个常用序列(T1:自旋回波T1加权像;T2:快速自旋回波T2加权像;PD:快速自旋回波质子密度像;GRE:梯度回波T1加权像;GE EPI:单次激发平面回波成像)的头颈部扫描,观察镍铬合金铸造冠对图像的影响。结果:1. 铸造冠未出现脱位;2.铸造冠周围组织的影像在T1、T2、PD、GRE畸变为近似圆形的低信号金属伪影,在GE EPI畸变为大范围的不规则的片状信号失落;T1的影像畸变(伪影)涉及3个扫描层面;T2 、GE EPI波及5个层面;影像畸变在PD、GRE较小,直径约14mm, 在GE EPI畸变最大,约达44mm。结论:1.戴有镍铬合金修复体可安全接受头颈部MRI检查;2. 镍铬合金修复体使其毗邻组织的磁共振成像发生畸变,其累及范围因扫描序列而异,对MR解剖影像影响较小,对MR功能影像影响较大。
Objective: To investigate the effects of the Ni-Cr alloy restorer on MR images. Methods: A casting Ni-Cralloy crown was put on a narcotized monkey's right upper lateral incisor. Then the monkey's head-and-neck was examinedwith a 2.0 T MR scanner. Four clinical routine scan sequences including spin echo (T1); fast spin echo (T2); proton density(PD); gradient echo (GRE) and one functional scan protocol (gradient echo planar image, GE EPI) were used to observethe effects of the Ni-Cr alloy crown on MR images. Results: 1.The casting crown was not dislocated during all the 5 scans.2. Metal artifact around the crown was found on all images with different size and shape. In the T1, T2, PD, GRE images,the artifacts were circular. While in the GE EPI images which were patch-shaped. In T1 images, artifact was found in 3slices, while 4 slices were affected in PD and GRE images. As for the T2 and EPI images, 5 slices were affected. Maximalartifact was found in EPI images with approximately 44mm in diameter. Minimal artifact was found in PD and GREimages with a diameter of approximately 14mm. Conclusions: 1.It is safe to receive a head-and-neck MRI examinationfor the patients with Ni-Cr alloy restorers.2. Ni-Cr alloy restorer results in distortion in all MR images. The distortion wasdifferent according to the scan sequence, which was less in the anatomical MR images than the functional MR images.
出处
《口腔颌面修复学杂志》
2002年第4期205-207,共3页
Chinese Journal of Prosthodontics
