磁性附着体的衔铁对磁共振成像的影响

目的：研究磁性附着体的衔铁对磁共振成像的影响。方法：体外实验选用MAGFIT EX400，MAGFIT EX600及MAGNEDISC 800型磁性附着体的衔铁，分别设计为不铸接、与镍铬合金铸接和与金钯合金铸接3种形式，并完成衔铁根帽的制作。体内实验选择需行磁性附着体可摘义齿修复的患者作为研究对象。用Siemens SONATA 1.5-T磁共振仪对所有样本及研究对象进行扫描，对体外样本伪影最大径进行测量和比较，对体内实验的伪影对头颈部解剖结构成像的影响进行分析。结果：MAGFIT EX400型、MAGFIT EX600型及MAGNEDISC 800型衔铁的伪影最大纵径分别为158.94、168.52和173.00 mm。衔铁伪影对颏部、舌、唇、软硬腭、颌骨的磁共振成像造成明显影响，位于后牙区的衔铁对脑及脊髓的成像造成影响。采用SE序列及左右向的频率编码，可以减小衔铁对头颈部MRI的影响。结论：磁性附着体的衔铁对磁共振成像有明显影响。

Impact of magnetic attachment keepers on magnetic resonance imaging examination

Objective:To evaluate the effects of magnetic attachment keepers on MRI images.Me-thods:In in vitro part,keepers of MAGFIT EX 400,MAGFIT EX 600 and MAGNEDISC 800 magnetic attachment systems were cast into standard root-caps with different alloy respectively,including nickel-chromium alloy and gold-palladium alloy,or not be cast for contrast.In in vivo part,volunteers with keepers in different position and amount were included.All the specimens and volunteers were imaged by a Siemens SONATA 1.5-T MRI scanner...