瘤周区多体素磁共振波谱在脑肿瘤鉴别诊断中的应用

Evaluation of Multivoxel ～1H-MR Spectroscopy in the PeritumoralArea of Human Brain Tumors

目的评价脑肿瘤周围区域多体素氢质子磁共振波谱(1H-MRS)在脑肿瘤诊断及鉴别诊断中的应用价值。方法搜集行常规MRI及多体素1H-MRS检查的脑肿瘤病变患者38例,包括胶质瘤15例、转移瘤9例、脑膜瘤14例(均为良性)。再根据WHO2000年分类标准,将脑胶质瘤分为低级别组(Ⅰ～Ⅱ级)8例,高级别组(Ⅲ～Ⅳ级)7例。所有患者检查前均未接受过化疗或放疗,没有脑外伤或/和脑手术史。常规扫描后增强前采用定点分辨磁共振波谱序列(PRESS)扫描,根据病灶的特征选定感兴趣区(ROI),ROI的大小既要包括肿瘤实质区、肿瘤周围区,也要尽可能涵盖对侧正常脑组织,又要避开骨骼、脑室、血管、坏死、囊变、出血、气体及钙化等区域。后处理应用MR机附带的波谱分析软件自动完成。计算脑胶质瘤、转移瘤及脑膜瘤实质区、周围区及对侧正常脑组织区代谢产物比值的平均值,进行组内、组间比较。P<0.05有统计学意义。结果多体素1H-MRS显示不同脑肿瘤的肿瘤实质区NAA/Cr、Cho/Cr和NAA/Cho平均值与对侧正常脑组织区比较有显著性差异(P<0.05);脑胶质瘤周围区与脑膜瘤、转移瘤的周围区以及高、低级别胶质瘤肿瘤周围区域多组代谢物比值具统计学差异(P<0.05)),高级别与低级别脑胶质瘤肿瘤周围区Glx/Cr的比值有显著性差异(P<0.05)。结论多体素1H-MRS技术可无创观察脑肿瘤患者脑代谢改变,有助于脑肿瘤的诊断、鉴别诊断、预测侵袭性病变的浸润范围以及脑胶质瘤的分级诊断等。

Objective To study the muhivoxel proton magnetic resonance spectroscopy （^1H-MRS） findings in peritumoral area of human brain tumors and to investigate the value of muhivoxel ^1H-MRS in evaluating of peritumoral area of brain tumors. Method A case-control experiment was performed from Dec. 2007 to Sep. 2008. Thirty-eight intracranial tumor patients were recruited in this study with 15 cases of gliomas, 9 cases .of metastases tumor and 14 cases of meningeomas. According to the classification criteria of WHO2000, 15 cases of glioma were divided into low-grade group（ I - II grade） and high-grade group （Ⅲ - IV grade）. All patients were not receiving chemotherapy or radiotherapy, and without injury or surgery before examination. Muhivoxel proton MRS was performed orderly using point-resolved spectroscopy（PRESS） sequence. The ROI was selected according to the feature of the focal. Spectra of three voxels were taken from parenchyma of the tumors, peritumoral region and corresponding contralateral normal appearing white matter, and these regions were evaluated in every patient. The areas of skeleton, brain ventricle, blood vessel, necrosis, bleeding area,gas and calcification were excluded from the voxel. Post-processing was completed with spectral analysis software automatically. Metabolite change of parenchyma, peritumoral region and contra lateral normal appearing white matter in the spectrum was measured. Result In muhivoxel ^1H-MRS from the parenchyma of the lesion, the ratios of NAA/Cho, NAA/Cr and Cho/Cr changed significantly by comparing with those of normal control brain tissues （P〈0.01）. Ratios of NAA/Cho, NAA/Cr and Cho/Cr also showed significant differences in peritumoral areas among different brain tumors and between the low-grade gliomas and high-grade gliomas （P〈0.05）. The low-grade gliomas and high-grade gliomas differed significantly in the ratios of Glx/Cr （P〈0.05）. Conclusion Evaluation of peritumoral region of brain tumors with muhivoxel ^1H-MRS combining with routine MRI scan may be useful in the diagnosis, differentiation, deciding the border of brain tumors and making the classification of glioma.