MR弥散加权成像对胶质瘤分级的临床应用

MR diffusion weighted imaging in the classification of gliomas

目的 评估DWI对胶质瘤分级的临床应用价值。方法 对经手术病理证实的 3 7例胶质瘤患者进行常规MRI序列扫描和DWI检查 ,对照分析病变的实质部分、坏死或囊变区、周围水肿区以及正常脑组织的ADC值、EDC值。结果 高级别胶质瘤瘤体的ADC值和EDC值分别较低级别胶质瘤瘤体低和高 (P≤ 0 .0 5 ) ,且取ADC值 12 .60× 10 -4mm2 /s为阈值时 ,其敏感度为 87.5 1% ,特异度为 73 .17% ,阳性预测值 (PPV)为 91.79% ,阴性预测值 (NPV )为 88.2 4%。高级别胶质瘤周围水肿区的ADC值 (EDC值 )明显低于 (高于 )低级别胶质瘤 (P≤ 0 .0 5 )。若取瘤周水肿ADC值取 14 .5 0× 10 -4mm2 /s作为高、低级别胶质瘤分级的阈值 ,则敏感度为 86.75 % ,特异度为 80 % ,PPV为 76.77% ,NPV为 86.67%。结论 ADC值(EDC值 )结合常规MRI序列的特征 ,对于胶质瘤的分级诊断具有临床应用价值。

Objective To investigate the clinical value of DWI in the classification of gliomas. Methods Thirty seven patients with histologically proved gliomas underwent routine and diffusion weighted imaging. Comparisons of apparent diffusion coefficients (ADC) and exponential diffusion coefficients (EDC) were done among tumor parenchymas, necrosis or cystic areas, peripheral edema regions and normal tissues. Results The ADC or EDC of high grade gliomas were respectively lower or higher than those of low grade ones ( P ≤0.05). When a threshold value of 12.60×10 -4 mm 2/s for ADC was selected for grading of gliomas, 87.51%, 73.17%, 91.79% and 88.24% for the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were achieved, respectively. The ADC (EDC) in peripheral edema regions of high grade gliomas were significantly lower (higher) than those of low grade ones ( P ≤0.05). ADC threshold value of 14.50×10 -4 mm 2/s for differentiation between high and low grade gliomas obtained 86.75%, 80.00%, 76.77% and 86.67% for the sensitivity, specificity, PPV and NPV, respectively. Conclusion The ADC (EDC) combined with routine MRI findings is of clinical application value in the classification of gliomas.