应用ROC曲线评价3.0T ~1H-MRS对脑胶质瘤分级的诊断效能

Evaluation of Diagnostic Efficiency of 3.0T ~1H-MRS in the Histopathological Grading of Brain Gliomas

[目的]分析脑胶质瘤氢质子磁共振波谱(~1H-MRS)表现,通过受试者工作特征曲线(receiver operating characteristic curve,ROC)来确定~1H-MRS各项代谢产物对胶质瘤分级的诊断效能。[方法 ]经病理证实的脑胶质瘤患者55例,按世界卫生组织(WHO)2007年胶质瘤分类分级标准,其中低级胶质瘤(Ⅰ、Ⅱ级)27例,高级胶质瘤(Ⅲ、Ⅳ级)28例;所有患者在术前行3.0T ~1H-MRS检查,检测肿瘤实质部分胆碱复合物(choline,Cho)/肌酸(creatine,Cr)、N-乙酰天门冬氨酸复合物(N-acetyl aspartic acid,NAA)/Cho、NAA/Cr值,并用ROC曲线分析各指标对胶质瘤分级诊断的敏感度、特异性及最佳诊断阈值。[结果]57例胶质瘤Cho/Cr值均较对侧正常脑组织升高,NAA/Cho及NAA/Cr值较对侧降低。低、高级胶质瘤肿瘤实质部分Cho/Cr、NAA/Cho比值差异有统计学意义(P<0.05),而NAA/Cr比值无统计学差异(P>0.05)。脑胶质瘤肿瘤实质部分的Cho/Cr比值与肿瘤级别呈显著正相关(r=0.600,P<0.001),而NAA/Cho比值与肿瘤级别呈显著负相关(r=-0.573,P<0.001),NAA/Cr值与肿瘤级别无明显相关(P>0.05)。Cho/Cr、NAA/Cho、NAA/Cr的ROC曲线下面积(area under curve,AUC)分别为0.847、0.831、0.530。取Cho/Cr=2.796为阈值鉴别不同级别脑胶质瘤,其敏感度为75.0%,特异性为85.2%;取NAA/Cho=0.349为阈值鉴别不同级别脑胶质瘤,其敏感度为85.2%,特异性为78.6%;NAA/Cr值对鉴别不同级别胶质瘤诊断意义不大。[结论]~1H-MRS能反映胶质瘤细胞的生化物质代谢情况,结合ROC曲线分析,Cho/Cr及NAA/Cho比值对胶质瘤分级诊断具有较大价值,可为脑胶质瘤术前分级诊断提供定量指标。

[Objective] To evaluate the diagnostic efficiency of 3.0T multivoxel proton magnetic spectroscopy（^1HMRS） in pathological grading of brain gliomas. [Methods] Fifty-five patients of pathologically proved brain gliomas,including 27 cases of low-grade gliomas（grade Ⅰ-Ⅱ） and 28 cases of high-grade gliomas（grade Ⅲ- Ⅳ）were enrolled in the study. Patients underwent 3.0T^1H-MRS examination before operation. The variety of metabolite peaks were detected,including the ratios of choline/creatine（Cho/Cr）,N-acetyl aspartic acid/Cho（NAA/Cho） and NAA/Cr. The sensitivity,specificity and cut-off value of each index were analyzed by receiver operating characteristic curve（ROC）. [Results] Significant differences were found in the ratios of Cho/Cr and NAA/Cho between low grade gliomas and high grade gliomas（P0.05）,but there was no significant difference in NAA/Cr（P0.05）. Significant correlation was found between the ratios of Cho/Cr,NAA/Cho and the pathological grading of gliomas. Significant positive correlation was found in ratio of Cho/Cr with the pathological grading of gliomas（r=0.600,P0.001）,and negative correlation was found in ratio of NAA/Cho with the pathological grading of gliomas（r =-0.573,P 0.001）. There was no significant correlation between the ratio of NAA/Cr and the pathological grading of gliomas.The area under the curve（AUC） of Cho/Cr,NAA/Cho,NAA/Cr were 0.847,0.831,0.530,respectively. The cut-off value of Cho/Cr for differential diagnosis of high grade and low grade brain gliomas was 2.796,with a sensitivity of75.0% and a specificity of 85.2%. The cut-off value of NAA/Cho for differential diagnosis of high grade and low grade brain gliomas was 0.349,with a sensitivity of 85.2% and a specificity of 78.6%. [Conclusion]^1H-MRS can reflect the metabolic information of brain gliomas. ROC curve analysis shows that the ratio of Cho/Cr and NAA/Cho may be of value in histopathological grading of brain gliomas