磁共振成像与CT在眼内非磁性异物诊断和定位中的比较

目的探讨磁共振成像（ｍａｇｎｅｔｉｃｒｅｓｏｎａｎｃｅｉｍａｇｉｎｇ，ＭＲＩ）和ＣＴ在眼内异物诊断和定位中的特点。方法以手术结果作为验证标准，比较２８例（４２枚）眼内非磁性异物在ＭＲＩ和ＣＴ图像上的显示及定位情况。结果４２枚眼内非磁性异物，ＭＲＩ和ＣＴ的检出率分别为９０．５％和９５．２％（ｘ２检验，Ｐ＞０．５）。ＭＲＩ与ＣＴ显示异物位置的准确率分别为８９．５％和６０．０％（ｘ２检验，Ｐ＜０．０５）。结论ＭＲＩ可用于眼内非磁性异物的诊断和定位，检出率高，在揭示异物与眼内组织的位置关系及显示眼内非磁性低密度异物方面优于ＣＴ，但对于眼球壁异物的显示则不如ＣＴ可靠。ＭＲＩ不宜用于眼内磁性异物的检查。

Comparison between magnetic resonance imaging and CT in detection and localization of non magnetic intraocular foreign bodies

Objective To approach the characteristics of magnetic resonance imaging (MRI) and CT in detection and localization of intraocular foreign bodies. Methods Metection and localization of 28 eases (42 foreign bodies) of non magnetic intraocular foreign body were compared in MRI and CT with criteria of operative results. Results The positive rates of MRI and CT in detection of 42 non magnetic intraocular foreign bodies were erspectively 90 5%and 95 2%(x 2test: P >0 5).The Positive rates of MRI and CT in localization were respectively 89 5%AND 60 0%(x 2 test: P <0 05).Conclusion MRI could be used in detection and localization of non magnetic intraocular foreign bodies with high positive rates in detection and superior to CT in demonstrating non magnetic intraocular foreign bodies with low density and the relationship between foreign bodies and intraocular tissues. MRI was not as believable as CT in detection of foreign bodies in eye wall and not an appropriat modality in examinations of magnetic intraocular foreign body.