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Background and Purpose malignant glioma and metastatic tumors are the two most common adult brain cancer, male and female incidence rate is very. Primary brain tumors gliomas account for 40% to 50%, in 2007 WHO classification of central nervous system tumors will be divided into Ⅳ grade gliomas, where Ⅰ ~ Ⅱ grade of low-grade gliomas, Ⅲ ~ Ⅳ level is high grade gliomas. Brain tumor metastases accounted for 40% of single brain metastases accounted for 25% to 30%. Imaging particular x-ray computed tomography scan (computerized tomography, CT), magnetic resonance imaging (magnetic resonance imaging, MRI) in both tumor localization and qualitative diagnosis plays an important role, particularly magnetic resonance imaging with no ionizing radiation, high soft tissue resolution and multi-dimensional imaging, etc., have become brain tumor lesion routine examination. However, the conventional imaging and brain glioma solitary metastasis in the differential diagnosis has great limitations. Since both the biological behavior of the tumor, clinical course, treatment options and prognosis are different, and therefore both correct preoperative diagnosis and identification of particular importance. In recent years, with the progress of MRI imaging equipment and computer level of progress, advanced MRI imaging techniques and the application of the new sequence is also increasing. Magnetic resonance diffusion tensor imaging (diffusion tensor imaging, DTI) is based on echo planar imaging (echo planar imaging, EPI) technology developed a tissue in vivo observation of microscopic diffusion of water molecules within the imaging methods, imaging speed , the choice of many parameters, including fractional anisotropy (fractional anisotropic, FA), apparent diffusion coefficient (apparent diffusion coefficient, ADC), volume ratio (volume ratio, VR), attenuation index (exponential attenuation, ExAt), each index anisotropy (anisotropy index, AI) and the eigenvalues (eigenvector, E1, E2, E3). Current use of DTI technique to diagnose brain white matter lesions, optic neuropathy and neoplastic lesions become a research hotspot. This paper aims to investigate the multi-parameter values DTI malignant glioma and metastatic brain tumor diagnosis and differential diagnosis of preoperative application value, in order to develop treatment programs for clinical diagnosis. Materials and Methods This study of 43 patients, were supratentorial mass, divided into groups of malignant glioma and metastatic tumor group. There are 27 cases of malignant glioma group, 27 lesions; metastases group of 16 patients, 21 lesions, including 7 cases of solitary metastases, nine cases of multiple metastases in 2 patients with multiple choice supratentorial 3 pieces lesions, 1 patient selection screen on two lesions, more than six cases of multiple metastases of the election on the screen a lesion. 43 cases of patients were based on pathology or medical history and follow-up confirmed. All patients were SIEMENS 3.0T MRI imaging scanners up DTI scans. DTI scanning routine preoperative MRI scan, all patients underwent conventional MRI enhanced scan. After scanning, the post-processing workstation on diffusion tensor image processing, respectively, choose a different area of interest (region of interest, ROI) for FA values, ADC value, VR value, ExAt value, E1, E2, E3 values are measured , including measurement of tumor parenchyma or cystic tumor wall, near peritumoral edema, far peritumoral edema and contralateral limb of internal capsule (or signal and location of the normal ipsilateral limb of internal capsule). Between groups were analyzed using two independent samples t-test, lesions in different groups were compared using ANOVA or KS rank sum test. Results 1. Malignant glioma group of 27 cases, including 11 cases of glioblastoma, 11 cases of astrocytoma WHO Ⅲ ~ Ⅳ grade, two cases of astrocytoma WHO Ⅱ ~ Ⅲ grade, one case of tumor oligodendrocytes WHO Ⅱ ~ Ⅲ grade, one case of mixed glioma WHO Ⅱ ~ Ⅲ grade (oligodendrocytes and astrocytes), one case of gliosarcoma. There are four cases of glioma patients with multiple brain lesions, lesion location and quantity were a total of two bilateral frontal, right frontal lobe and basal ganglia of two, a total of two left temporal occipital lobe, right temporal occipital of 2; due to tumor is too small or another benign tumor foci WHO grade migraine were therefore choose one revenue information. Metastases in 16 cases, 21 lesions, including seven cases of solitary metastases, multiple metastases in 9 cases. 2 graphics performance analysis: (1) FA map: Malignant gliomas and metastases group of 48 lesions in a substantial part of the tumor and peritumoral edema showed low signal, the performance of dark color, are visible mass effect. (2) ADC map: ADC map, a substantial part of malignant glioma tumor signal intensity with normal brain behaves differently, in which 19 showed other signals, five showed a slightly lower signal, three showed slightly high signal; peritumoral edema 23 showed high signal intensity than white matter, 4, etc., and showed lower signal. Necrotic tumors showed high signal. Tumor metastases substantial part of the signal intensity changes varied, 12 showed other signals, eight showed slightly lower signal, a slightly hyperintense lesions showed. Peritumoral edema 17 showed high signal, four showed nearly equal and slightly lower signal. (3) VR diagram: The object of study 48 cancer tumor and peritumoral edema in the VR graph showed high signal, while the white matter fiber bundles showed low signal, the tumor area shows no white matter fiber bundles, peritumoral edema District sparse white matter fiber bundles, amputation or because of a sudden change in pressure and direction of travel and displacement. (4) ExAt chart: this study 48 tumors showed a near-solid part of the brain parenchyma or hypointense signal, and cystic necrosis within the tumor and peritumoral edema showed significantly lower signal. Showed high signal within the capsule. (5) E1, E2 and E3 Figure: The research subjects 47 solid part was slightly lower than in the white matter on the map E1 signals, a malignant glioma was equal to the white matter signal; 48 cystic tumors , necrosis and peritumoral edema showed a high signal. E2 and E3 on the map 48 solid part of the tumor was slightly lower than the other, and white matter signal, tumor edema showed significantly higher signal. 3. Parameter Value Analysis (1) ADC ratio: nearly two tumor ADC between peritumoral edema ratio were significantly different, malignant gliomas ADC ratio of 1.985 ± 0.456, metastatic tumor group was 2.289 ± 0.516, t = -2.161 , P = 0.036. For the comparison group, malignant gliomas and metastases of the tumor parenchyma group, near and far peritumoral edema peritumoral edema are present between any two statistical difference, P less than 0.05. (2) FA ratio: the ratio of two tumor parenchyma FA statistically significant difference between, P = 0 lt; 0.001, malignant glioma group FA ratio was 0.243 ± 0.102, metastases group FA ratio of 0.120 ± 0.054 The former was significantly higher than the latter. About the comparison group, malignant glioma group parenchyma, near and far peritumoral edema peritumoral edema ratio between any two of the FA difference was not statistically significant (P values were greater than 0.05); substantial tumor metastases enhancement area, near and far peritumoral edema peritumoral edema FA ratio exists between any two were significantly different (P values less than 0.05). (3) VR ratio can identify malignant glioma and partial tumor metastases (P value equal to 0.038), the former is 2.4714 ± 0.635, which was 3.188 ± 1.592. VR ratio can identify a substantial part of metastases and distant peritumoral edema. (4) ExAt ratios for glioma and metastatic tumors was not statistically significant pairwise comparisons. But ExAt ratio measurement can well distinguish between malignant gliomas and metastases tumor parenchyma, near and far peritumoral edema peritumoral edema. (5) between the two groups of tumor parenchyma and peritumoral edema near E3 ratios were significantly different; far edema tumor groups E1, E2 and E3 ratios were not statistically different. For nearly two cancer tumor and peritumoral edema, far peritumoral edema identification comparison, E1, E2, E3 ratio in gliomas and metastases were statistically different (P less than .05). Conclusion 1. FA ratio, VR ratio, E3 ratio helps to identify malignant gliomas and metastases tumor sections. 2. ADC ratio, E3 ratio can identify malignant glioma and metastatic tumors near peritumoral edema. 3. ADC ratio, ExAt ratio, E1 ratio, E2 ratio, E3 ratio can distinguish malignant glioma brain tumor parenchyma, near and far peritumoral edema peritumoral edema. 4. FA ratio, ADC ratio, ExAt ratio, E1 ratio, E2 ratio, E3 ratio can distinguish brain metastases tumor parenchyma, near and far peritumoral edema peritumoral edema. VR ratio can identify a substantial portion of brain metastases and distant peritumoral edema. 5.DTI help differentiate malignant glioma and metastatic brain tumors
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