3.0T 1H-MRS及DTI诊断脑胶质瘤: AA值与FA值的相关性

目的 探讨脑胶质瘤肿瘤外周至肿瘤中心3.0T磁共振氢质子波谱(¹H-MRS)的N-乙酰天门冬氨酸(NAA)值及弥散张量成像(DTI)的各向异性(FA)值的相关性,评价¹H-MRS及DTI对脑胶质瘤的诊断价值。方法 回顾性分析经组织病理学证实的9例低级别(Ⅰ~Ⅱ级)胶质瘤、16例高级别(Ⅲ~Ⅳ级)胶质瘤的常规MRI、DTI及¹H-MRS资料,分析肿瘤不同感兴趣区的部分FA值、NAA与肌酸(Cr)比值、胆碱(Cho)与肌酸(Cr)比值及胆碱(Cho)与NAA的比值,并观察NAA值与FA值的相关性。结果 从肿瘤中心到外周(包括肿瘤邻近脑白质和对侧大脑半球白质)FA和NAA数值持续升高,且两者呈正相关(r=0.90,P<0.05)。低级别、高级别胶质瘤组瘤体的NAA/Cr无明显差异,FA、Cho/Cr和Cho/NAA差异均有统计学意义(P均<0.05)。结论 脑胶质瘤中,从肿瘤外周至肿瘤中心脑胶质瘤对周围组织的浸润程度逐渐增加,而NAA值及FA数值表现为降低趋势,反映了神经元结构和白质纤维的完整性的破坏。肿瘤中心FA、Cho/Cr和Cho/NAA数值对鉴别低级别、高级别胶质瘤具有一定意义。

Application of 3.0T magnetic resonance spectroscopy and diffusion tensor imaging in evaluating cerebral gliomas: Correlation of NAA value and FA value

Objective To investigate the correlation of NAA value and FA value of cerebral gliomas and the periphery with magnetic resonance spectroscopy (¹H-MRS) and diffusion tensor imaging (DTI), and to explore their value in diagnosing classification of cerebral gliomas. Methods ¹H-MRS and DTI data of 25 patients with cerebral gliomas (including 9 low-grade gliomas and 16 high-grade gliomas ) confirmed pathologically were analyzed retrospectively. FA values and NAA/Cr, Cho/Cr and Cho/NAA ratios of different region of interest (ROI) were calculated and the correlations of FA values and NAA ratios were analyzed. Results FA and NAA value from the tumor center to the periphery (the adjacent white matter and the contra-lateral hemisphere) continuously increased, and there was positive correlation (r=0.90, P<0.05). NAA/Cr in low-grade gliomas and high-grade gliomas had no significant difference, while FA, Cho/Cr and Cho/NAA were statistically different (P<0.05). Conclusion In gliomas, the degree of tissue infiltration increases continuously from the surrounding toward the center of the tumor, accompanied with a concordant decrease of NAA and FA value, which reflect a destructing of neuronal structures and white matters' integrity. The value of FA, Cho/Cr and Cho/NAA in tumor center has some significance to identify low-grade and high-grade gliomas.