The Applying Value Of Diffusion Kurtosis Imaging In Grading Of Cerebral Astrocytomas

Objective To evaluate the applying value of diffusion kurtosis imaging parameters in grading of cerebral astrocytomas. Methods Collect34patients of cerebral astrocytomas from Shan Xi NO.1Hospital from Jan2012to Dec2013. Conventional MRI scanning, enhanced scanning and DKI examination were performed and measured the mean kurtosis (MK) values、fractional anisotropy (FA) values and Mean diffusivity (MD) values of the solid part and the tumor contralateral normal-appearing white matter (NAWM), on the MK figure, FA figure and MD figure. MK, FA, MD in solid tumors were also normalized for MK’、FA’、MD’ to the corresponding values in contralateral normal-appearing white matter (NAWM) after age correction and were compared among tumor grades.To evaluate the significance of All the values difference between high-grade (H-GD) and low-grade (L-GD) astrocytomas.(P<0.05significance level, Mann-Whitney-Wilcoxon test). Results MK were significantly higher in H-GD astrocytomas than in L-GD astrocytomas (P=.020).Optimal thresholds for mean kurtosis was0.54. The sensitivity and specificity for discriminating between H-GD and L-GD astrocytomas were found for MK (76.1%and84.6%, respectively),AUC for MK was0.886. FA and MD did not significantly differ between astrocytoma grades (P>0.05). All values normalized to the values in the contralateral NAWM were significantly different between H-GD and L-GD astrocytomas (MK’, P=.024; FA1, P=.033; and MD’, P=.031). Optimal threshold for MK1differentiating H-GD from L-GD astrocytomas was0.50. The sensitivity and specificity for discriminating between H-GD and L-GD astrocytomas were found for MK’((85.7%and76.9%, respectively). AUC was0.897. Optimal thresholds for FA’differentiating H-GD from L-GD astrocytomas was0.62. The sensitivity and specificity for discriminating between H-GD and L-GD astrocytomas were found for FA’(71.4%%and69.2%, respectively). AUC was0.762. Optimal thresholds for MD’differentiating H-GD from L-GD astrocytomas was1.54. The sensitivity and specificity for discriminating between H-GD and L-GD astrocytomas were found for MD1(80.9%and61.5%, respectively). AUC was0.788. Conclusion There were significant differences in kurtosis parameters between H-GD and L-GD astrocytomas; hence, better separation was achieved with these parameters than with conventional diffusion imaging parameters.