| [Objective] Magnetic resonance diffusion tensor imaging(DTI) is an emerging technology in recent years. This technology not only finds processes which hard to find in routine magnetic resonance imaging,but also uses 3D to display courser direction of nerve fiber bundle. This study also uses diffusion tensor tractography to reconstruct chief nerve fiber bundle which surrounding tumors ,to mix together with tumors, and evaluates use value in neurosurgery .[Materials and Methods] 30 cases of neurepithelial tumors including 20 high-grade neurepithelial tumors (WHO grade III-IV) and 10 low-grade neurepithelial tumors (WHO grade I — II).All the cases were proved pathologicallyroved clinically and were performed by precontrast MRI scan(including conventional sagittal T1 -weighted images and coronal T2-weighted images, axial T1/T2/DW images) and postcontrast MRI scan (including sagittal, coronal and axial T1-weighted images). All the cases were underwent precontrast diffusion tensor imaging, the raw data were processed offline on the workstation to form the corresponding maps of color-encoded tensor/DCavg/FA. Used the T1WI/T2WI/ADC/T1WI+C/b=0 images as the reference, DCavg/FA was measured in each region of interest(ROI), including solid part of tumor; cystic part of tumor; peritumoral edema; "normal" appearance white matter surrounding the edema("normal" means no abnormity on conventional MRI); normal white matter distant from tumor; and contralateral corresponding ROIs of the last three. In order to exclude the influence of patients' age and difference of ROIs' anatomic location, we cacultated the ratios to the contralateral corresponding ROI of peritumoraledema and white matter surrounding the edema. To calculate the Pearson correlation and the significant difference between each parameter of bilateral normal white matter distant from tumor, then apply the paired samples t-test. The parameter or parameter ratio of the other parts used the ANOVA.If homogeneity of varianc, we uses independent samples t-test for statistical analysis, otherwise uses rank sum test.P value less than 0.05 was considered significant difference. 9 cases which major white matter bundles of the lesion side was involved with tumor and/or edema performed 3D reconstruction by DTV1.5. By VolumnOne, 3D tumor and/or edema was merged with white matter tract.,furthermore analysis the relationship between major white matter bundles and tumors shape changing of major white matter bundles and the relationship with clinical symptom. [Results]1. DC_avg maps showed the cystic part of tumor and peritumoral edema more clearly, and the gray and white matter demonstrated the similar signal. Compared with the brain parenchyma, solid part of tumor; cystic part of tumor and peritumoral edema demonstrated iso/slightly hyperintense signal; hyperintense signal; hyper/slightly hyperintense signal on the DC_avg maps.Maps of FA provided a much better constract of gray and white matter. Compared with the white matter, solid part of tumor; cystic part of tumor and peritumoral edema demonstrated iso/hypo/slightly hypointense signal; hypointense signal and hypo/slightly hypointense signal on the FA maps, and they could not show the boundary of tumor and edema clearly.2. Calculation of Pearson coefficient demonstrated the high relativity of DCavg/FA of bilateral normal white matter distant from tumor(r was 0.943, 0.732, P<0.0001), and paired samples t-test showed no significant difference between each parameter of bilateral normal white matter(t was 0.1945 0.8823, P>0.05). The parameter or parameter ratio of the other parts which used the ANOVA indicatehomogeneity of varianc,thus t-test should be used to analysis statistical significance.The DCavg of tumor solid part in low-grade neurepithelial tumors and high-grade neurepithelial tumors werel.0339±0.1723 and 0.9265±0.2422 (mean± SD, unit 10~-3mm2/s) respectively, the difference was not significant between two groups( t= 1.2337, P>0.05). The FA of two groups were 0.1563 ±0.06312 和 0.1321 ±0.04351, no significant differences between two groups was found (t=1.9823, P>0.05) .The DC_avg of tumor cystic part in low-grade neurepithelial tumors and high-grade neurepithelial tumors were 2.1878 + 0.2956 和 2.0339±0.4751(mean±SD, unit 10~-3mm2/s) , The FA of two groups were 0.0912 ±0.0412 and 0.07513 ± 0.02374,no significant difference (t=0.9332, P>0.05) and (t= 1.3620, P>0.05) between two groups respectively.Parameter ratio of peritumor edema: The DCavg ratio of in low-grade neurepithelial tumors and high-grade neurepithelial tumors were 1.0519±0.0275 和 1.0440 +0.0160(mean±SD, unit 10'3mm2/s), no significant differences could be found (t=0.9991, P>0.05) .FA ratio of two groups were 0.5328±0.2618 和 0.2151 ±0.1613 respectively, which showed statistical significance between two groups (t =4.1177, P<0.05) .Parameter ratio of "normal" appearance white matter surrounding the edema: The DCavg ratio of low-grade neurepithelial tumors and high-grade neurepithelial tumors were 1.0448 + 0.1391 和 1.0323 ±0.2402(mean±SD, unit 10"3mm2/s), no significant differences could be found (t=0.2000, P>0.05) . FA ratio of two groups were 0.6754 ± 0.2659 和 0.2590 ±0.1942, which showed statistical significance between two groups (t=4.8912, P<0.05) .3. Reconstruction 9 cases with tumors and major white matter bundles using DTT technique.Among the 9 cases ,there are only conpress and displace of white matters of the lesion side in two cases,and signal indensities are not changed .White...
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