摘要目的 评价ADC值在神经上皮肿瘤分级中的诊断价值.方法 回顾性分析70例经病理证实为神经上皮肿瘤患者的临床和影像资料,根据2007年WHO中枢神经系统分类标准,将所有患者分为低级别组40例(WHO Ⅰ或Ⅱ级)和高级别组30例(WHOⅢ或Ⅳ级).患者术前均行MR平扫、DWI及增强扫描,在ADC图上测量肿瘤组织的最小ADC值,术后利用免疫组织化学的方法确定Ki-67指数.两组间最小ADC值的比较采用成组t检验,年龄及Ki-67指数比较采用Mann-Whitney检验,最小ADC值与Ki-67指数的相关性采用Pearson相关性分析,应用ROC曲线来分析评价最小ADC值区分神经上皮肿瘤级别的能力.结果 低级别组平均最小ADC值[(1.08±0.31)× 10~(-3) mm~2/s]大于高级别组[(0.74±0.18)×10~(-3) mm~2/s],差异有统计学意义(t=5.42,P＜0.05＝.低级别组Ki-67指数[范围0～50%,中位数为4%]小于高级别组[范围0～75%,中位数为25%],差异有统计学意义(U=325.50,P＜0.05＝.最小ADC值与Ki-67指数呈负相关(r=-0.30,P＜0.05＝.ROC曲线下面积为0.85,区分高、低级别组肿瘤的最佳截断值为0.86×10~(-3) mm~2/s,此时,诊断高级别神经上皮肿瘤的敏感性为90.0%,特异性为77.5%.结论 最小ADC值有助于神经上皮肿瘤的分级判定.

abstractsObjective To investigate the predictive value of ADC value in grading of neuroepithelial tumors. Methods The clinical data and images of 70 patients with neuroepithelial tumors pathologically proven were collected and analyzed restrospectively. All the patients were classified into low(WHOⅠ or Ⅱ)and high(WHO Ⅲ or Ⅳ)grade groups which included 40 and 30 cases respectively accroding to the 2007 WHO classification of tumours of the central nervous system. All the patients underwent plain and contrast-enhanced MR scan and DWI before surgery. The minimum ADC(MinADC)value was measured postoperatively on ADC maps. The Ki-67 labeling index(Ki-67 LI)of tumor tissue was determined by immunohistochemistry.MinADC values for two groups were analyzed using student t test, while the age and Ki-67 LI for the two groups was analyzed using Mann-Whitney test(P＜0.05 considered to be significant＝.Also the MinADC valHe and Ki-67 LI were analyzed with Pearson correlation. The receiver operating characteristic analysis was used for evaluation for grading neuroepithelial tumors of the patients using MinADC. Results The mean MinADC value[(1.08±0.31)×10~(-3) mm~2/s]of the low grade group was significantly higher than that[(0.74±0.18)×10~(-3) mm~2/s]of the high grade group(t=5.42,P＜0.05＝,and the Ki-67 LI of the low grade group[0-50%,median 4%]was significantly lower than that[0-75%,median 25%]of the high grade group(U=325.50,P＜0.05＝.There was a negative correlation between MinADC value and Ki-67 LI(r=-0.30,P＜0.05＝.The area under the ROC curve was 0.85,and the cutoff MinADC value of 0.86×10~(-3) mm~2/s for the differentiation between high and low grade neuroepithelial tumors provided the best combination of sensitivity(90.0%)and specificity(77.5%)(receiver operatingcharacteristic analysis).Conclusion MinADC value is helpful for prediction of neuroepithelial tumor grade.