扩散张量成像及扩散张量纤维束成像在颅脑肿瘤诊断中的应用价值

摘要

目的 探讨磁共振扩散张量成像(DTI)及纤维束成像(DTT)在星形细胞瘤、脑膜瘤与转移瘤肿瘤实质区的应用价值,通过对表观扩散系数(ADC)及各向异性分数(FA)的测量分析,观察脑白质与纤维束的关系,为临床提供有价值的信息.方法 对32例经病理证实的脑肿瘤患者,其中不同级别星形细胞瘤12例、良性脑膜瘤10例、转移瘤10例,分别测量肿瘤实质区与对应区正常脑组织的平均ADC值和FA值,分析其ADC值和FA值的差异并观察3种脑肿瘤对白质纤维束的影响.结果 星形细胞瘤、脑膜瘤或转移瘤患者组内肿瘤实质区与对侧正常脑组织FA值差异有统计学意义(P＜0.05),星形细胞瘤、脑膜瘤、转移瘤患者肿瘤实质区的FA值分别为0.07±0.03、0.14±0.05、0.16±0.07,P＜0.05.星形细胞瘤及转移瘤患者肿瘤实质区ADC值较对侧正常脑组织高(P＜0.05)；脑膜瘤患者肿瘤实质区ADC值与对侧正常部位无显著性差异(P＞0.05)；星形细胞瘤、脑膜瘤和转移瘤患者肿瘤实质区ADC值差异有统计学意义(P＜0.05).在DTT图中星形细胞瘤和转移瘤多数表现为纤维束部分中断、受压、偏移或变形移位；脑膜瘤纤维束呈现为稀疏,移位.结论 测量肿瘤实质区ADC值及FA值可用于鉴别脑内和脑外的肿瘤,如星形细胞瘤与脑膜瘤的鉴别或转移瘤与脑膜瘤的鉴别,其中ADC值有显著的鉴别意义；DTT可清晰显示正常白质纤维束和肿瘤的解剖关系,有利于术前方案的制定.%Objective To discuss the value of diffusion tensor imaging ( DTI) and diffusion tensor tractography (DTT) in the solid part of astrocytoma, meningioma and metastasis. To measure and analysis ADC and FA in the tumor parenchyma region, observe the relationship between alba and fiber bundle, and provide more useful information for clinical diagnosis. Methods Thirty-two patients were pathologically proven brain tumor, 12 cases of astrocytomas with various grades, 10 cases of benign meningiomas, 10 cases of solitary metastasis. To measure the ADC value and FA value in the tumor parenchyma and corresponding contralateral normal brain tissue on the average ADC and FA diagrams. To analysis the differences of the average ADC value and FA value between the two kinds of tumors and observe cerebral white matter fiber bundle effect of the three tumors. Results Astrocytoma, meningioma or metastasis tumor parenchyma within the patient group compared with the contralateral normal brain tissue, FA values were significantly different (P < 0.05). In the tumor parenchyma of astrocytoma, meningioma and metastasis patient group, FA value was 0.07 ± 0. 03, 0. 14 ± 0. 05, 0.16 ± 0.07 respectively (P < 0.05). ADC values of astrocytoma and metastasis tumor parenchyma were higher than those of normal brain tissues ( P < 0. 05). Meningioma tumor parenchyma compared with the contralateral normal part of ADC value had no significant difference (P >0.05). ADC value was significantly different in the tumor parenchyma of astrocytoma, meningioma and metastasis patient group ( P < 0. 05). Astrocytoma and metastasis mostly illustrated on DTT map showed partial disruption, compression, deviation and displacement of fiber bundles. Most of the meningioma fiber bundles showed significant rarefaction and displacement. Conclusions Measurement of tumor parenchyma ADC and FA values can be used to identify the astrocytoma and meningioma or metastasis and meniiigioma. ADC values were obvious meanings. DTT can clearly show the normal white matter fiber tracts and tumor anatomy, therefore it is conducive to the development of preoperative program.