常用口腔金属和陶瓷材料在不同场强磁共振上伪影的实验研究

Experimental Measurement of MRI Artifacts Caused by Common Metallic Dental Materials and Common Ceramic Dental Materials on Different Field-strength Mmagnets

[目的]通过对5种口腔常用金属和陶瓷材料在3种场强磁共振成像设备上以T1、T2序列进行扫描、观察、比较其伪影情况,为临床提供指导。[方法]依据标准模型的左上中切牙为牙体标准,用5种金属和陶瓷材料分别制作内冠,作为本次研究的试件。分别在0.35T、1.5T和3.0T磁共振成像设备上进行扫描,得到T1和T2像。依据有关标准和测量面积来分析比较伪影情况。[结果]氧化锆在3种场强磁共振的T1、T2像中均无伪影,铸瓷、贵金属合金、镍铬合金与钴铬合金在3种场强磁共振的T1、T2像中均可产生不同程度的伪影,且伪影面积依次增大。钴铬合金和镍铬合金测定值偏高,其中钴铬合金较其他4种材料偏高(P﹤0.05),镍铬合金较贵金属合金、铸瓷高(P﹤0.05);虽然在各种场强下,同种材料T2像伪影面积较T1像减小,4种材料的均值也是T2像伪影面积较T1像减小,但无统计学意义(P>0.05)。[结论]常用口腔金属材料会引起磁共振成像伪影,1.5T磁共振重于0.35T,3.0T磁共振重于1.5T。常用口腔陶瓷材料基本无伪影或伪影不明显。

[Objective]To measure and compare the MRI artifacts caused by common metallic dental materials and common ceramic dental materials on different field-strength magnets.[Methods] A total of 3 common metallic dental materials and 2 common ceramic dental materials were tested with 0.35T, 1.5T and 3.0T MR imagers. The artifact areas on these 3 different field-strength magnets were measured and statistically compared. [Results]Zirconia in three field magnetic resonance（NMR） in T1 and T2 as no artifacts, casting porcelain, metal alloy, nickel chromium alloy and CoCr-alloy in three fields magnetic resonance（NMR） in T1 and T2 as all can produce different degree of artifacts, and artifacts area increased in turn. Cobalt chromium alloy and nickel chromium alloy measurements on the high side, the cobalt chromium alloy than other four kinds of materials on the high side（P〈0.05）,high nickelchromium alloy was precious metal alloy, casting porcelain（P〈0.05）. [Conclusions]Commordy used metallic dental materials could cause MR artifacts and image degradation. Compared with that on 0.35T, the artifact was increased on 1.5T magnet. Compared with that on 1.5T, the artifact was increased on 3.0T magnet.