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目的 1探讨MR弥散张量成像(diffusion tensor imaging,DTI)及纤维束成像(diffusion tensor tractograghy,DTT)技术显示良、恶性脑肿瘤与周围脑白质纤维束解剖关系在手术前中的临床价值。2探讨DTI在高级别与低级别胶质瘤中的诊断价值。主要为ADC值、FA值及FDi值的应用。3利用DTT定量分析测量正常人的皮质脊髓束(corticospinal tract,CST)的FDi值与FA值,并探讨两者之间的相关性。方法对49例脑肿瘤行常规MRI及DTI检查,应用Philips公司提供的(Fiber track)软件包分析处理,分别获取各自的部分各向异性图(FA图)、彩色编码张量图及脑白质纤维束图,分析肿瘤与瘤周白质纤维束的关系。测量10例低级别胶质瘤与15例高级别胶质瘤肿瘤实质区、瘤周水肿区、邻近白质区及对侧正常白质区的ADC值、FA值及FDi值。对11例健康正常人行DTI检查,通过感兴趣区(region of interest,ROI)的设置得出双侧CST三维示踪图像,并由软件计算获得双侧CST的条目数及FA值,由公式FDi(纤维密度指数)=纤维束条目数/ROI面积或像素,求得相应FDi值。结果1良性及恶性肿瘤,瘤周白质纤维束都可以发生移位;瘤周水肿区白质纤维束表现为浸润和破坏为主,其破坏程度与肿瘤的恶性程度呈正比。2低级别胶质瘤及高级别胶质瘤相应瘤周水肿区的ADC值高于实质区的ADC值;两者的实质区、瘤周白质区及及正常对侧白质区ADC值之间均有统计学意义;而高级别胶质瘤肿瘤实质区的ADC值(1.265±0.064)×10~(-3) mm~2/s高于低级别胶质瘤ADC值(10.75±0.032)×10~(-3) mm~2/s,两者差异具有统计学意义。低、高级别胶质瘤肿瘤实质区FA值与瘤周水肿区FA值之间相比差异无统计学意义,与邻近白质区及对侧白质区FA值差异具有统计学意义。低级别胶质瘤实质区的FA值(0.175±0.036)明显低于高级别胶质瘤肿瘤实质区的FA值(0.223±0.051),且两者之间有显著差异。低级别胶质瘤水肿区FDi值高于高级别胶质瘤,且两者差异具有统计学意义。3正常健康人皮质脊髓束的FA值与FDi值具有正的线性相关,(r=0.773,P<0.05)。结论 1磁共振DTI及DTT技术可在活体中清晰、直观、无创地显示脑肿瘤与周围白质纤维束的关,对术前恶性脑肿瘤的治疗方案的确定提供了重要的依据。2DTI结合常规MRI检查,有助于鉴别高、低级别胶质瘤。3 FDi是白质纤维束定量化指标,是对FA值的量化与补充。
Objective To investigate the clinical value of MR diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) in the preoperative analysis of the anatomic relationship between benign and malignant brain tumors and the surrounding white matter fibers. 2 To investigate the diagnostic value of DTI in high-grade and low-grade gliomas. Mainly ADC value, FA value and FDi value of the application. 3 The DTi quantitative analysis was used to measure the FDi value and FA value of normal human corticospinal tract (CST), and to explore the correlation between the two. Methods Forty-nine patients with brain tumors underwent routine MRI and DTI examinations. The data were analyzed and processed by using the Fiber track software package provided by Philips Company. Their partial anisotropy maps (FA maps), color-coded tensor maps and white matter fibers Beam map, analyze the relationship between tumor and peritumoral white matter fiber bundles. The ADC value, FA value and FDi value were measured in 10 cases of low grade glioma and 15 cases of high grade glioma tumor parenchyma, peritumoral edema area, adjacent white matter area and contralateral normal white matter area. DTI examination was performed on 11 normal healthy subjects. The bilateral CST images were obtained by setting region of interest (ROI), and the number of bilateral CST entries and FA values were calculated by software. The formula FDi (Fiber Density Index) = number of fiber bundle entries / ROI area or pixel to find the corresponding FDi value. Results 1 Benign and malignant tumors, peritumoral white matter fiber bundles can shift; Peritubular edema white matter fiber bundles showed infiltration and destruction of the main, the extent of the damage and tumor malignancy was proportional to. The ADC value of the corresponding peritumoral edema area in low-grade gliomas and high-grade gliomas was higher than that in the real area. The ADC values in the parenchyma, peritumoral white matter and normal white matter (1.265 ± 0.064) × 10 ~ (-3) mm ~ 2 / s in high grade gliomas were higher than that in low grade gliomas (10.75 ± 0.032) × 10 ~ (-3) mm ~ 2 / s, the difference was statistically significant. There was no significant difference between the FA values in the low and high grade gliomas and the FA values in the peritumoral edema area and between the adjacent white matter and the contralateral white matter areas. The FA value of the low grade gliomas (0.175 ± 0.036) was significantly lower than that of the high grade gliomas (0.223 ± 0.051), and there was a significant difference between the two. Low-grade glioma edema area FDi value higher than high-grade glioma, and the difference was statistically significant. There was a positive linear correlation between FA value and FDi in normal healthy human corticospinal tract (r = 0.773, P <0.05). Conclusions 1 Magnetic resonance imaging (DTI) and digital subtraction angiography (DTT) can clearly and intuitively display the relationship between brain tumor and the surrounding white matter fiber bundles in vivo, which provides an important basis for the treatment of malignant brain tumors. 2DTI combined with conventional MRI examination, help identify high and low grade glioma. 3 FDi is a quantitative index of white matter fiber bundle, which is the quantification and supplement of FA value.