氢质子磁共振波谱在脑星形细胞瘤强化区中的应用

Proton magnetic resonance spectroscopy of enhancement regions in brain astrocytomas

目的探讨氢质子磁共振波谱(1H-MRS)在脑星形细胞瘤强化区中代谢物特点及其与病理分级的相关性。方法选择26例脑星形细胞瘤患者,经病理证实的低级别星形细胞瘤(LGA)12例、间变性星形细胞瘤(AA)7例和胶质母细胞瘤(GBM)7例,并分成LGA组、AA组和GBM组3组。所有患者术前均行磁共振(MR)常规扫描和增强扫描,随后行二维多体素1H-MRS检查,检测肿瘤强化区及对侧正常参照区N一乙酰天冬氨酸(NAA)、胆碱(Cho)、肌酐(Cr)、乳酸(Lac)和肌醇(mI)代谢物浓度,比较3组间肿瘤强化区和各组内肿瘤强化区与对侧正常参照区NAA/Cr、Cho/Cr及NAA/Cho比值平均值变化情况。结果脑星形细胞瘤强化区波谱表现NAA下降,Cho升高,22例出现Lac峰,24例出现mI峰。脑星形细胞瘤3组各组内肿瘤强化区与对侧正常参照区NAA/Cr、Cho/Cr及NAA/Cho比值差异均有统计学意义(P<0.05)。强化区Cho/Cr比值在LGA组与AA组、GBM组之间差异均有统计学意义(P<0.05),Lac和mI在各组间差异均无统计学意义(P>0.05)。结论1H-MRS可提高对脑星形细胞瘤诊断及分级的准确性,并提供了一个定量分析的方法。

Objective To evaluate the proton magnetic resonance spectroscopy （^1H-MRS） pattern of metabolites in enhanced regions of brain astrocytoma, which may be helpful for pathological tumor grading. Methods Twenty-six cases of pathologically confirmed astrocytomas including 12 of low-grade astrocytoma （group LGA）, 7 of anaplastic astrocytoma （group AA） and 7 of glioblastoma muhiforme （group GBM） were studied, Prior to surgery, all the patients underwent routine and enhanced MRIs, followed by ^1H MR spectroscopy of the enhanced tumor regions and contralateral reference regions to measure the levels of N-acetylaspartate （NAA）, Choline （Cho）, Creatine （Cr）, Lactate （Lac） and myo-inositol （mI）. Ratios of NAA/Cr, Cho/Cr and NAA/Cho of both the enhanced tumor regions and contralateral reference regions were compared among the three groups. Results Decreased NAA and increased Cho levels were shown by 1H MR in regions of enhancement, Lac peaks were detected in 22 patients and ml peaks in 24. In all the three groups, the NAA/Cr, NAA/Cho and Cho/Cr ratios of enhanced regions changed significantly compared with those of contralateral reference regions. A significant difference in Cho/Cr ratios of the enhanced regions was found among the three groups of astrocytoma （P〈0.05）, but the differences in mI and Lac of the three groups were statistically unremarkable （P〉0.05）. Conclusion ^1H MRS may improve diagnostic accuracy of astroeytoma and provide a helpful technique of quantitative analysis for tumor grading on MR images.