高级别胶质瘤和转移瘤的磁共振波谱及灌注成像研究

Magnetic Resonance Spectroscopic and Perfusion MRI in High Grade Gliomas and Metastases

目的通过磁共振波谱(MRS)及灌注成像(PI)研究肿瘤强化区域、肿瘤周围区域的细胞代谢和血管分布特点,探讨MRS及PI对高级别胶质瘤和转移瘤的鉴别诊断价值。资料与方法23例颅内肿瘤患者,包括高级别胶质瘤(Ⅲ～Ⅳ级)13例,转移瘤10例,行常规MRI、PI和单体素MRS检查。MRS检查主要观察的代谢物有:氮-乙酰天门冬氨酸(NAA),胆碱(Cho),肌酸(Cr/PCr),计算NAA/Cr,Cho/Cr,NAA/Cho比值。PI观察指标为相对脑血容量(rCBV)。采用SPSS10.0软件进行统计学分析。结果MRS提示高级别胶质瘤和转移瘤肿瘤强化区域均出现NAA/Cr与NAA/Cho降低,Cho/Cr升高;两种肿瘤强化区域各项比值之间的比较差异均无统计学意义(P>0.05);高级别胶质瘤肿瘤周围组织亦出现NAA/Cr与NAA/Cho降低,Cho/Cr升高,与转移瘤肿瘤周围组织相比差异均有统计学意义(P<0.05)。高级别胶质瘤和转移瘤肿瘤强化区域的rCBV值分别为4.05±2.04,3.84±2.44,两者之间差异无统计学意义(P>0.05),肿瘤周围组织的rCBV值分别为1.31±0.14,0.56±0.22,两者之间差异有统计学意义(P<0.05)。结论结合肿瘤强化区域与肿瘤周围区域的MRS和PI,有助于提高对高级别胶质瘤和转移瘤的鉴别能力。

Objective To discuss whether magnetic resonance spectroscopy and perfusion MRI can be used to differentiate high grade gliomas and metastases on the basis of the differences in metabolite levels and vascularity in the pefitumoral zone and enhancing regions of tumors. Materials and Methods 33 patients with brain tumor （ 13 high grade gliomas （WHO Ⅲ - Ⅳ） and 10 metastases） were performed with conventional MRI, perfusion MRI, single voxel MRI spectroscopy. The metabolites of N acetylaspartate （NAA） ,choline （Cho） ,and creatine （Cr） were analyzed in MRS examination. The peak area ratio of NAA/Cr,Cho/Cr,NAA/Cho were calculated, rCBV were analyzed in perfusion MRI. SPSS10.0 software was used to analyze the significant difference between the two kinds of tumors. Results All the enhancing region of the two kinds of tumors were characterized by reduced NAA/Cr , NAA/Cho and increased Cho/Cr, which had no significant difference. Reduced NAA/Cr, NAA/Cho and increased Cho/Cr were also found in the pefitumoral zone of high grade gliomas, which difference were statistically significant in the pefitumoral zone between the two kinds of tumors （P 〈 0.05 ）. The measured rCBV in the enhancing region of high grade gliomas and metastases were 4.05 ±2.04 and 3.84 ± 2.44 respectively, which had no significant difference （ P 〉 0.05 ）. rCBV of the peritumoral zone of high grade gliomas and metastases were 1.31 ± 0. 14and0.56 ± 0.22, respectively, which had significant difference （ P 〈 0.05 ）. Conclusion Conventional MR imaging combined with perfusion MRI and single voxel MRS can improve the differential diagnostic ability between high grade gliomas and metastases.