The Value Of Diffusion Tensor Imaging And Susceptibility-weighted Imaging In Grading Gliomas

Objective:To evaluate the grading effectiveness of combined diffusion tensor imaging and susceptibility-weighted imaging in patients with gliomasMaterials and Methods:The MRI data of twenty-nine patients with histologically proved brain gliomas were retrospectively analyzed.According to the2007 World Health Organization classification of tumours of the central nervous system,the patients were divided into high-grade group(15 cases) and low-grade group(14 cases).All patients were underwent MRI,enhanced MRI,DTI,and SWI before surgeon.①We measured maximum fractional anisotropy values(FAmax),minimum fractional anisotropy values(FAmin),mean fractional anisotropy values(FAmean), the range of fractional anisotropy values(FArange),minimum apparent diffusion coefficient values(ADCmin),mean apparent diffusion coefficient values(ADCmean) by placing ROIs within solid tumor components and measured FAmean values, ADCmean values by placing ROIs within peritumoral edema.Then using independent sample t-test analysised whether each parameter value of high- and low-grade group had statistical significant.A ROC curve was further applied to identify the optimal threshold of each parameter value that yielded the best combination of sensitivity and specificity,to distinguish high- from low-grade gliomas.②we counted the classification results of intratumoral susceptibi1 ity signal intensity.Then using Mann-Whitney U test analysised whether the ITSS grading of high- and low-grade group had statistical significant, using Spearman rank correlation analysised the correlation between ITSS grade and pathological grade.A ROC curve was further applied to identify the optimal threshold of ITSS that yielded the best combination of sensitivity and specificity,to distinguish high- from low-grade gliomas.③We combined DTI and SWI to distinguish high- from low-grade gliomas,and obtained the sensitivity and specificity.Results :① FAmax values,FAmean values and FArange values in high-grade group werehigher than the low-grade group within solid tumor components,ADCmin values and ADCmean values in high-grade group were lower than the low-grade group within solid tumor components,there were statistical differences between them(P<0.05).There was no statistical significant between high- and low-grade group in FAmin values(P> 0.05).FAmax values had the best effectiveness of all parameters in solid tumor components,and the area under the ROC curve was 0.871,the best threshold was 0.384,the sensitivity was 93.3%,the specificity was 78.6%.② FAmean values in peritumoral edema of high-grade group was lower than the low-grade group,ADCmean values was higher than the low-grade group,both of them had statistical significant(P<0.05).③ The ITSS grade of high-grade group was mostly in grade of II or III,and the ITSS grade of low-grade group was mostly in grade of 0 or I.There was statistical significance in ITSS grade between high- and low-grade group cerebral glioma((Z =-3.784,P <0.05). 1),there was positive correlation between the grade of ITSS and the histological grade of cerebral glioma(r = 0.703,P <0.05).The area of ITSS grade under the ROC curve was 0.891,threshold value was the grade of II,sensitivity was80%,specificity was 93.3%.④ Sensitivity and specificity for the FAmax and combination ITSS grade were100% and 78.3%.Conclusion:①In DTI and SWI,high- and low-grade gliomas had certain characteristics.Both of them can contribute to the grading of gliomas and work as a supplement to conventional MRI sequences.②Combined DTI and SWI can improve the diagnostic efficacy of cerebral glioma grading.