ADC和3D-ASL不同感兴趣区勾画及测量方法对胶质瘤分级的影响

The Effect of Different ROI Placing and Measuring Methods on ADC and 3D-ASL for Grading of Gliomas

目的探讨表观扩散系数(ADC)和3D动脉自旋标记(3D-ASL)不同感兴趣区(ROI)勾画和测量方法对胶质瘤分级的影响。方法回顾性分析经病理证实的胶质瘤患者27例(低级别胶质瘤9例,WHOⅡ级;高级别胶质瘤18例,WHOⅢ、Ⅳ级),术前行磁共振常规序列平扫和增强扫描、扩散加权成像(DWI)、3D-ASL扫描,通过手动勾画肿瘤整体容积(WT)、最大代表性层面(RS)的实性部分作为ROI,测量ADC、相对脑血流量(rCBF)的均值(ADCmean、rCBFmean)和直方图参数(ADC 20th、rCBF 90th)。两组间参数比较采用独立样本t检验,采用受试者工作特征曲线(ROC)和Binary逻辑回归分析诊断效能,利用Delong法比较曲线下面积(AUC)。结果两种ROI勾画法所得的四组ADC参数在高、低级别胶质瘤组间具有显著统计学差异(P<0.01),组间AUC均无统计学差异(P>0.05),RS-ADC 20th诊断效能最佳(AUC=0.907)。RS-rCBF 90th组间差异具有统计学意义(P<0.05),其余rCBF参数均无统计学差异(P>0.05)。RS-ADC 20th联合RS-rCBF 90th的诊断效能最高,AUC=0.944(0.863~1.000)。结论测量胶质瘤最大层面实性部分的ADC 20th和rCBF 90th分级效能最佳,且两者联合的分级效能优于单一成像技术。

Objective To explore the effect of different ROI placing and measuring methods on ADC and 3 D-ASL for grading of gliomas.Methods Twenty-seven patients with pathologically proven gliomas(lowgrade,WHOⅡ,n=9;highgrade,WHOⅢ、Ⅳ,n=18)were analyzed retrospectively.3 D-ASL,DWI,and routine MRI sequences were performed on all patients before surgery.The mean values and histogram parameters on ADC and rCBF were measured by manually sketching the whole tumor region and representative-tumor region.The independent sample t-test was used to compare the parameters of each group.Binary logistic regression and receiver operating characteristic(ROC)curve analyses were used to assess the diagnostic effciency,Delong method was used to compare AUC.Results The ADC values of two ROI setting methods of HGG group were significantly higher and had significant difference in comparison to LGG group(P<0.05).Although the area under the curve(AUC)of different ADC values had no significantdifference(P>0.05),RS-ADC 20 th showed the best diagnostic performance of glioma grading(AUC=0.907).The difference between groups of RS-rCBF 90 th had statistical significance(P<0.05),but the other rCBF parameters had no(P>0.05).The diagnostic efficiency of RS-ADC 20 th combined with RS-rCBF 90 th were highset(AUC=0.944).Conclusion The diagnostic efficiency of RS-ADC 20 th and RS-rCBF 90 th measured by representative-tumor ROI was highest and the combination of the two was better than one parameter.