多形性胶质母细胞瘤MR弥散张量成像应用研究

目的本研究旨在探讨平均扩散系数（ADC）和各向异性指数（FA）在鉴别多形性胶质母细胞瘤肿瘤组织、水肿及正常脑组织,以及探讨ADC值及FA值在对肿瘤浸润范围中的作用。方法14例多形性胶质母细胞瘤在治疗前行常规MRI、增强扫描及弥散张量成像（DTI）,在T1WI增强、T2WI上确定肿瘤组织、水肿及正常脑组织,在ADC图和FA图上测量这些区域的FA值及ADC值,用方差分析评定值之间的差异。结果肿瘤囊变区的ADC值（2.07±0.631）×10^-3mm^2/s最高,其次为水肿区（1.39±0.164）×10^-3mm^2/s、肿瘤强化中心（1.13±0.187）×10^-3mm^2/s、肿瘤强化边缘（1.04±0.254）×10^-3mm^2/s、瘤周正常白质区（0.779±0.088）×10^-3mm^2/s、对侧正常白质（0.748±0.082）×10^-3mm^2/s。对侧正常白质FA值最高（0.538±0.084）×10^-3mm^2/s,肿瘤囊变区最低（0.09±0.028）×10^-3mm^2/s。肿瘤强化边缘与囊变坏死区、水肿区、瘤周正常白质以及对侧正常白质ADC值差别均具有显著性意义（P〈0.05）,瘤周正常白质区与对侧正常白质区ADC值无显著性意义（P〉0.05）。肿瘤强化边缘与囊变坏死区、瘤周正常白质区、对侧正常白质区FA值差别均具有显著性意义（P〈0.05）,瘤周正常白质区与对侧正常白质区FA值有显著性意义（P〈0.05）,肿瘤强化边缘FA值与水肿区FA值差异无显著性意义（P〉0.05）。结论ADC值可用于区分多形性胶质母细胞瘤正常脑白质、水肿和肿瘤强化边缘,FA值对于组织学鉴别无明显意义,FA值对肿瘤浸润范围有重要的意义。

Diffusion tensor MR imaging of glioblastoma multiforme

Objective To evaluate the value of fractional anisotropy (FA) and apparent diffusion coefficients (ADC) measurement in differentiating tumor, edema, and normal white matter regions and whether they are helpful in differentiating tumor invasion. Methods Fourteen patients with glioblastomas multiforme underwent conventional MR, contrast-enhanced structural and diffusion tensor MR imaging before therapy. Tumor, edema, and normal-appearing white matter regions were determined on contrast-enhanced T1-weighted structural images, T2-weighted structural images. FA and ADC were measured in each tissue type in the ADC maps and FA maps. Differences in these values among the tissue types were assessed with a standard analysis of variance. Results ADC was highest in the necrotic tumor core (2.07±0.631)×10^-3 mm²/s, followed by edema region (1.39±0.164)×10^-3 mm²/s, enhancing tumor core (1.13±0.187)×10^-3 mm²/s, enhancing tumor margin (1.04±0.254)×10^-3 mm²/s, the normal-appearing white matter adjacent to the tumors (0.779±0.088)×10^-3 mm²/s and contralateral normal white matter (0.748±0.082)×10^-3 mm²/s. FA was highest in contralateral normal white matter (0.538±0.084)×10^-3 mm²/s, and lowest in the necrotic core (0.09±0.028)×10^-3 mm²/s. Significant differences of ADC were found in enhancing tumor margins compared with necrotic tumor core, edema region, normal-appearing white matter adjacent to the tumors and contralateral normal white matter, while there was no differences between the normal-appearing white matter adjacent to the tumors and contralateral normal white matter. Significant differences of FA were found in enhancing tumor margins compared with necrotic tumor core; the normal-appearing white matter adjacent to the tumors and contralateral normal white matter, and significant differences of FA were also found in the normal-appearing white matter adjacent to the tumors and contralateral normal white matter, while there was no differences between enhancing tumor margins and edematous brain. Conclusion ADC values can be used to differentiate normal white matter, edema region, and enhancing tumor margins. FA values add no benefit to tissue differentiation. FA value is helpful in detecting tumor invasion.