弥散张量成像纤维密度指数和平均纤维长度值在胶质瘤分级诊断中的价值

The study of fiber density index and mean fiber length values by using diffusion tensor imaging on diagnosis of gliomas grading

目的使用纤维密度指数(FDi)和平均纤维长度值作为弥散张量成像(DTI)定量指标分析不同级别胶质瘤瘤内、瘤周及健侧脑区神经纤维结构微观差别。方法使用Diffusion Toolkit及TrackVis软件分析50例胶质瘤(WHOⅡ级12例,Ⅲ级15例,Ⅳ级23例)DTI数据,计算瘤内、瘤周及健侧脑区FDi值和平均纤维长度值,并使用SPSS 17.0软件进行统计学分析。结果Ⅱ、Ⅲ、Ⅳ级胶质瘤肿瘤区FDi值和平均纤维长度值均低于对应级别瘤周区、健侧脑区(P均<0.05);Ⅱ、Ⅲ、Ⅳ级胶质瘤肿瘤区FDi值均无统计学差异(P均>0.05),平均纤维长度值均有统计学差异(P均<0.05);Ⅱ级胶质瘤瘤周区FDi值及平均纤维长度值均高于Ⅲ、Ⅳ级胶质瘤瘤周区(P均<0.05),且Ⅱ级胶质瘤瘤周区FDi值高于健侧脑区(P<0.05);Ⅲ、Ⅳ级胶质瘤瘤周区FDi值无统计学差异(P>0.05),平均纤维长度值有统计学差异(P<0.05);Ⅱ、Ⅲ、Ⅳ级胶质瘤肿瘤区FDi值和平均纤维长度值均低于对应级别瘤周区(P均<0.05)。结论 FDi值和平均纤维长度值联合使用对胶质瘤影像分级诊断有一定的价值。

Objective To investigate the delicate differences of nerve fibers in tumors,peritumoral regions and normally contralateral brain regions between WHO Ⅱ,ⅢandⅣ grade gliomas by using measurable indicators such as fiber density index（FDi）values and mean fiber length values.Methods 50 cases of brain tumors underwent MR and DTI scanning（12 cases were diagnosed asⅡ grade gliomas,15 cases were diagnosed asⅢ grade gliomas,23 cases were diagnosed asⅣ grade gliomas）.We achieve FDi values and mean fiber length values in tumors,peritumoral regions and normally contralateral brain regions by using softwares such as Diffusion Toolkit and TrackVis.Results FDi values and mean fiber length values in tumors were lower than those in peritumoral regions and normally contralateral brain regions at the same grade between WHO Ⅱ,Ⅲ andⅣ grade gliomas（all P〈0.05）.There were statistical differences of mean fiber length values in tumors betweenⅡ,ⅢandⅣ grade gliomas（all P〈0.05）,whereas there were no statistical differences of FDi values in tumors between Ⅱ,Ⅲ and Ⅳ grade gliomas（all P〈0.05）.FDi values and mean fiber length values ofⅡ grade gliomas in peritumoral regions were both higher than those ofⅢandⅣ grade gliomas,and mean fiber length values ofⅡ grade gliomas in peritumoral regions were also higher than those in normally contralateral brain regions（P〈0.05）.There were statistical differences of mean fiber length values in peritumoral regions between ⅢandⅣ grade gliomas（P〈0.05）,whereas there were no statistical differences of FDi values in peritumoral regions between Ⅲ and Ⅳ grade gliomas（P〉0.05）.FDi values and mean fiber length values in tumors were lower than those in peritumoral regions at the same grade betweenⅡ,Ⅲ andⅣ grade gliomas（all P〈0.05）.Conclusion The values of FDi and mean fiber length are helpful to identify different grade gliomas.