镍铬合金固定修复体对MRI影像的影响

The effects of the fixed prothesis made of Ni-Cr alloy on MRI

目的 研究镍铬合金固定修复体对MRI影像的影响。方法 用镍铬合金制作冠修复体，分为A组～F组6组。分别戴于志愿者口内。用SIEMENS NOVUS 1．5T磁共振仪，标准SE序列T1加权像对每组修复体进行轴位和矢状住扫描。用GRE序列和EPI序列对F组进行重复扫描。用eFilm分析软件对各组实验的MRI图像作分析。结果 随着镍铬合金修复体体积增加，MRI影像上的伪影面积扩大，产生伪影的层数增多，范围主要在面下1／3。结论 以镍铬合金为材料制作的冠、桥，对MRI影像有一定的影响，伪影范围局限在面下1／3。

Objective To investigate the effect of the fixed prothesis made of Ni - Cr alloy on the MRI images. Methods Firstly, we made crowns with Ni- Cr alloy for a healthy volunteer＇s teeth. The crowns were divided into six groups, from group A to group F. Then they were put on teeth in order. Examined the volunteer＇s head and neck with a SIEMENS NOVUS 1.5T MRI scanner in axial and sagittal position. Standard SE （T1） sequence was used to observe the the effects of each group. GRE sequence and EPI sequence were also used. The size of the artifacts were well recorded and analysed with eFilm medical software. Results As the amount of the crowns increases, the size of the distortion region increases, and the layers with artifacts also increase. The artifacts are limited in the lower maxillofacial area. Conclusion Fixed prothesis made of Ni - Cr alloy do create artifacts in MRI examination. However, the artifacts are limited in the lower maxillofacial area.