DWI在幕上原始神经外胚层肿瘤影像诊断中的应用价值

The Diagnostic Value of DWI and ADC Values of the Supratentorial Primitive Neuroectodermal Tumors

目的探讨DWI对幕上原始神经外胚层肿瘤(SPNET)的诊断价值,为临床诊断提供依据。方法回顾性分析18例经手术后病理确诊的SPNET的完整MRI资料,并绘制ADC图,测量瘤体实质及对侧正常脑组织的ADC值,采用配对t检验进行分析。结果成人发生15例,3例发生于儿童,病灶体积大,边界清,瘤周水肿轻或无,囊变多见,可伴出血;MRI上瘤体多呈T1WI等或低信号,T2WI稍高或高信号,增强扫描明显强化;DWI呈等高或高信号,肿瘤实质区平均ADC值[(0.662±0.131)×10-3mm2/s]较正常脑实质[(0.844±0.094)×10-3mm2/s]低,差异有统计学意义(t=10.217,P<0.05)。结论 DWI及ADC值与瘤体内部病理变化相关,是常规MRI的有力补充。

Objective To evaluate the diagnostic value of DWI on the supratentorial primitive neuroectodermal tumors（ SPNET）,and provide the basis for clinical diagnosis. Methods To analyze retrospectively 18 patients with complete MRI data who were pathologically confirmed with SPNET,ADC values were measured in real terms of the tumor and contralateral normal brain tissue,using paired t-test. Results 15 cases occurred in adults,3 cases occurred in children; the tumors were large,clear boundary,more common cystic and with lesser extent peritumoral edema or no edema,sometimes it may be associated with bleeding; solid components of tumors show hypointensity or isointensity in T1 WI,slight hyperintensity or hyperintensity in T2 WI,and enhanced scan showed ＂signet ring-like＂or ＂honeycomb-like＂enhancement. Lesions on DWI showed hypointensity or hyperintensity,tumor parenchymal mean ADC value[（ 0. 662 ± 0. 131） × 10- 3mm2/s]is lower than the normal brain parenchyma[（ 0. 844 ± 0. 094） × 10- 3mm2/ s],and the difference was statistically significant（ t = 10. 217,P 〈 0. 05）. Conclusion DWI and ADC values are associated with the pathological changes of internal tumor closely,which is powerful complement of conventional MRI