瘤周水肿区扩散加权成像在胶质瘤分级中的应用价值

Application of diffusion weighted imaging in peritumoral edema regions for grading of gliomas

目的通过分析瘤周水肿区相对表观扩散系数(rADC)值,探讨扩散加权成像(DWI)在胶质瘤分级中的应用价值。方法收集我院在治疗前行常规MRI及DWI检查的幕上胶质瘤共28例,其中低级别胶质瘤(Ⅱ级)10例,高级别胶质瘤(Ⅲ～Ⅳ级)18例。以瘤周1cm为界线,将胶质瘤瘤周水肿区划分为近瘤区及远瘤区,分别测量ADC值,并计算相应的rADC值。结果Ⅱ级胶质瘤的近瘤区rADC值(1.74±0.25)与远瘤区rADC值(1.86±0.21)间差异无统计学意义(P=0.14)。Ⅲ～Ⅳ级胶质瘤的近瘤区rADC值(1.61±0.38)明显低于远瘤区rADC值(1.94±0.57),差异有统计学意义(P=0.00)。Ⅱ级胶质瘤与Ⅲ～Ⅳ级胶质瘤的近瘤及远瘤区rADC值差异均无统计学意义(P均>0.05)。结论瘤周水肿区rADC值能反映高级别胶质瘤瘤周渐变浸润现象,但在Ⅱ级与Ⅲ～Ⅳ级胶质瘤分级中的应用价值有限,不能作为瘤周区肿瘤细胞浸润的量化指标。

Objective To assess the application value of diffusion weighted imaging （DWI） in the grading of gliomas by analyzing the relative apparent diffusion coefficient （rADC） values of peritumoral edema regions. Methods Twenty-eight patients with supratentorial tumors, including 10 cases of low grade （ Ⅱ ） glioma and 18 cases of high-grade （Ⅲ-Ⅳ ） glioma before treatment were involved in this study, and all patients underwent conventional MRI and diffusion weighted imaging. The peritumoral edema regions of the glioma were divided into adjacent peritumoral region and distal peritumoral region according to borderline which had 1 centimeter distance from the edge of the tumor. The ADC values in different peritumoral edema regions were measured respectively, and the rADC values were calculated correspondingly. Results The rADC values of grade Ⅱ gliomas indicated no statistically significant difference （P=0. 14） hetween adjacent peritumoral edema regions （1.74±0.25） and distal peritumoral edema regions （1.86±0.21）. The rADC values in adjacent peritumoral edema regions of grade Ⅲ -Ⅳ gliomas （1.61 ±0.38） were significantly lower than that of distal peritumoral edema regions （1.94±.57）, and the difference in the rADC values was statistically significant （P=0.00）. The rADC values in adjacent and in distal peritumoral edema regions of grade Ⅱ gliomas were compared respectively with that of grade Ⅲ -Ⅳ gliomas （both P〉0.05）. Conclusion The rADC values can provide information about biological action of high grade gliomas that the tumor cells gradually infiltrate the peritumoral region, but the application value of rADC in peritumoral edema is limited in the grading of gliomas between grade Ⅱ and grade Ⅲ-Ⅳ. The rADC values in peritumoral edema regions can not be regarded as a quantitative index of the tumor cells infiltrating peritumoral regions.