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The Role of DTI in Evaluating Pathological Characteristic of Gliomas and the State of Adjacent Fiber Tracts

Author: FeiXiaoRui
Tutor: NiuChaoShi；FuXianMing
School: Anhui Medical University,
Course: Surgery
Keywords: Diffusion tenor imaging Glioma fiber tract Pathology Biology
CLC: R739.4
Type: Master's thesis
Year: 2008
Downloads: 57
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Abstract

Diffusion tensor imaging(DTI) is a technique that is sensitive to the ordered anisotropic diffusion of wateralong white matter fiber tracts which is based on diffusion weighted imaging(DWI).It can detect subtle changes in white matter fiber tracts in disease and visualization of individual white matter fiber tracts and their relationships with cerebral neoplasms in vivo.Gliomas are the most common primary neoplasms of the central nervous system that can cause damage to the surrounding brain white matter fiber tracts which lead to their states alteration.The states of white matter fiber tracts are correlated with the malignancy of glioma.Objeetive The role of diffusion tensor imaging in evaluating pathological characteristic of gliomas and the states of adjacent fiber tracts.Methods Regular MRI and DTI were performed in 24 patients(16 men,8 women;mean age,46 years) with histologically confirmed brain gliomas.Regions of interest were placed in the white matter adjacent to the tumor with the lowest FA(FAa) and in the white matter of the contralateral hemisphere(FAc).The values of FAa and FAc were measured.In the regions of the identical layer,the values of ADCa,ADCc were measured.Relative fractional anisotropy ratios(rFA) and relative apparent diffusion coefficient ratios(rADC) were calculated.The fiber tracts adjacent gliomas reconstructed with 3-dimensional,the state of fiber tracts were evaluated with displaced,infiltrated or destroyed.Reflection the infiltration of glioma of MMP-9、CD44 and the proliferative activity of VEGF and Ki-67 expression were evaluated by SP immunohistochemical staining method in surgical specimens.The correlation of rFA,rADC,the expression of MMP-9,CD44,VEGF, Ki-67 and the grade of gliomas were analyzed statistically,including independent samples t test,tendencyχ~2 test,rank sum test and Kruskal-Wallis test.Result Eleven of the 24 tumors were demonstrated as low-grade gliomas(WHO gradeⅠ-Ⅱ) and thirteen were high-grade gliomas(WHO gradeⅢ-Ⅳ).With low-grade gliomas, the values of FAa were slightly lower compared with FA_c and the values of ADCa were higher than ADCc.Median rFA and rADC were 0.648±0.186 and 1.4294±0.498;with high-grade gliomas,the values of FAa were lower compared with FA_c and the values of ADCa were also higher than ADCc.Median rFA and rADC were 0.272±0.059 and 1.8454±0.317.Significant differences of rFA(P＜0.01) and not rADC(P＞0.05) were found between low-grade and high-grade gliomas.The expression of VEGF or Ki-67 was higher in high-grade glimas than low grade(P＜0.05) and a negative correlation(P＞0.05) between MMP-9 or CD44 expression and the grade of gliomas was found.The states of fiber tracts were damaged greatly in the periphery of high-grade gliomas than low grade(P＜0.05). Further,the states of fiber tracts were destroyed heavily in the periphery of gliomas that had higher expression of VEGF or Ki-67(P＜0.05).But there were poor correlation (P＞0.05) between MMP-9 or CD44 expression and the state of fiber tracts adjacent to gliomas.Conclusion DTI can depicts the localization of gliomas and the states of adjacent fiber tracts in the periphery of gliomas,rFA can distinguish between high-grade and low-grade gliomas.The proliferation of gliomas but not the infiltration influences the state of fiber tracts in the periphery of gliomas.It was helpful to estimate the biological behavior of gliomas on imagings and useful in deciding the therapeutic regimen.

The Role of DTI in Evaluating Pathological Characteristic of Gliomas and the State of Adjacent Fiber Tracts

Abstract

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