磁共振弥散加权成像在囊性脑膜瘤诊断中的应用

目的　探讨囊性脑膜瘤的磁共振表现、表观弥散系数（ADC）图的影像特点、ADC值与病理分级的关系及ADC值对判断不同病理亚型脑膜瘤的价值。方法　回顾性分析2003年3月－2007年12月18例经病理证实的囊性脑膜瘤患者的磁共振表现，其中男8例，女10例，平均年龄45.6岁。在ADC图上分别测量肿瘤实质、瘤周水肿、囊变区的平均ADC值（均取4～6个区域，取平均值），比较不同病理亚型、不同病理分级的肿瘤实质、瘤周水肿、囊变区的ADC值差异是否有统计学意义。结果　良恶性脑膜瘤肿瘤实质ADC值差异无统计学意义（P＞0.05）；囊性脑膜瘤各亚型间的肿瘤实质、瘤周水肿的ADC值差异无统计学意义（P＞0.05）；肿瘤实质、囊变区与瘤周水肿平均ADC值相比差异均有统计学意义（P＜0.05）。结论　ADC值可区分肿瘤实质、囊变区及瘤周水肿，但对脑膜瘤亚型及良恶性的甄别需结合常规MRI与增强的征象。Objective　ToexploretheMRIimagingmanifestation,featuresofapparentdiffusioncoefficient(ADC)mapandtherelationshipsamongADCvalue,pathologicgradingandpathologicsubtypeofcysticmeningioma.Methods　Theclinicaldataof18patients(8malesand10females,withanaverageageof45.6years)withcysticmeningiomasconfirmedbypathologicallyexaminationwereretrospectivelyanalyzed.TheADCvaluesoftumorparenchyma,peritumoraledema,cysticregionsandthecontralateralnormalbrainofthetumorparenchymaweremeasuredandanalyzed.TheADCvalueofthetumorparenchyma,peritumoraledema,cysticregionweremeasuredandthencomparedwiththepathologicalfindings.Pvalueoflessthan0.05wasconsideredashavingastatisticallysignificantdifference.Results　TherewasnosignificantdifferenceinADCvaluesbetweenbenignandmalignantmeningiomaandalsoamongthetumorparenchyma,periedemaandcysticregionindifferentpathologicalsubtypes.ThedifferenceinADCvaluesamongsttumorparenchyma,peritumoraledemaandcysticregionwerestatisticallysignificant(P＜0.05).Conclusions　AlthoughADCquantitativemeasurementallowsthedifferentiationofthetumorparenchyma,cysticregionandperi-edema,itisneedtocombinedwithconventionalMRexaminationtoassesstumormalignancyaswellasgradingincysticmeningioma.