眼内异物MRI临床应用研究

ClinicalapplicationofMRIinintraocularforeignbodies

目的：通过分析４２例５５枚眼内异物的ＭＲＩ表现，并与ＣＴ和Ｘ线平片比较，探讨了ＭＲＩ对眼内异物的诊断价值。材料与方法：男３３例，女９例，年龄５～４５岁。５５枚眼内异物中非磁性异物５３枚，铁磁性异物２枚。每例均在术前１个月内完成Ｘ线平片、ＣＴ和ＭＲＩ检查。结果：（１）ＭＲＩ对５５枚眼内异物检出率（９４％）和ＣＴ（９１％）相仿（Ｐ＞０．２５），均明显高于Ｘ线平片（４２％）（Ｐ＜０．００５）；（２）ＭＲＩ对眼内异物相关并发症的显示优于ＣＴ，而其对巩膜异物的显示差于ＣＴ；（３）ＳＥ序列Ｔ２ＷＩ和ＰＤＷＩ（质子密度加权成像）是检出眼内异物的优选序列；（４）非磁性异物ＭＲＩ呈信号缺失区，无伪迹产生；而铁磁性异物产生大量伪迹，并可致眼部额外损伤。结论：ＭＲＩ是检出眼内非磁性异物的有效方法，特别适用于Ｘ线平片和ＣＴ不能显示的少数非金属异物。眼内铁磁性异物不适于ＭＲＩ。

Purpose:ToevaluateMRIinintraocularforeignbodiesascomparedwithCTaswelasconventionalX-rayfilms.Materialsandmethods:Therewere55intraocularforeignbodiesin42patients,33malesand9femalesagerangedfrom5～45years.Fifty-threeofthe55foreignbodieswerenon-magnetic,andtheremaining2wereferromagneticobjects.ConventionalX-rayfilms,CTandMRIexaminationswereaccomplishedwithinonemonth.Results:(1)Thepositiverateforshowing55intraocularforeignbodieswassimilaronMRI(94%)andCT(91%)(P>0.25),butmuchhigherthanconventionalX-rayfilms(42%)(P<0.005);(2)MRIwassuperiortoCTforthedemonstrationofeyecomplicationsrelatedtotheforeignbodies,butthecontrarywastruewhentheywerelocatedwithinthesclera;(3)T2WIandPDWIofSEsequencewerethemethodofchoiceforthedemonstrationoftheseforeignbodies;(4)non-magneticforeignbodiesusualyshowedsignallosswithoutartifactonMRI,whileferromagneticsubstancesproducedremarkableartifactandmightleadtoaccidentalinjuryoftheeye.Conclusion:MRIwasaneffectivemethodfortheevaluationofnon-magneticforeignbodiesoftheeye,especialyforthenon-metalicforeignbodiesundetectablewithCTorconventionalX-rayfilm.Itwasnotrecommendedforferromagneticforeignbodies.