胚胎发育不良性神经上皮瘤的常规MRI与DWI特征

Conventional MRI and DWI characteristics of dysembryoplastic neuroepithelial tumors

目的探讨胚胎发育不良性神经上皮瘤(DNT)的常规MRI、DWI特征及其病理基础。方法回顾性分析24例经手术病理证实的DNT的常规MRI、DWI及病理学表现。在ADC图上测肿瘤及对侧正常脑实质ADC值,并进行比较。结果常规MRI上肿瘤多见于额叶和顶叶。11例肿瘤呈尖端指向脑室的三角形或扇形,8例呈类圆形,4例呈脑回状,1例为大脑半球内弥漫结节状病变。17例肿瘤位于大脑半球凸面,9例肿瘤邻近颅骨受压变薄。23例单发肿瘤呈T1WI低信号,T2WI均呈高信号。18例患者接受T2W FLAIR序列检查,其中12例肿瘤周围见薄环状高信号。13例肿瘤未见明显强化,9例肿瘤内见强化。肿瘤周围未见明显水肿。20例肿瘤平均ADC值(1.98×10-3 mm2/s)大于对侧正常脑实质(0.83×10-3 mm2/s,t=20.44,P<0.01)。24例肿瘤内均见特殊的胶质神经元成分,7例病理诊断为单纯型DNT,17例为复杂型DNT。结论 DNT的常规MRI表现具有一定特征性,与肿瘤内特殊的胶质神经元成分有关;DNT的ADC值明显增高,有助与其他脑皮质区肿瘤相鉴别。

Objective To analyze conventional MRI and DWI characteristics of dysembryoplastic neuroepithelial tumors（DNT） and their pathological foundations.Methods Conventional MRI,DWI and pathological manifestations of 24patients with pathologically confirmed DNT were analyzed retrospectively.ADC values of DNT and the contralateral normal brain parenchyma were measured and compared.Results On conventional MRI,the tumors mostly located in the frontal lobe and parietal lobe.Eleven tumors showed triangular pattern pointing towards the cerebral ventricle,8showed nodular pattern,4showed gyriform configuration,and 1showed diffuse nodules in cerebral hemisphere.Deformity of the overlying skull was observed in 9of the 17patients with cortical tumors of the convexity.The tumor displayed hypointense on T1WI,hyperintense on T2WI in 23cases.On FLAIR T2WI,thin ring sign at the periphery was found in 12of 18tumors.The tumor did not enhance in 13cases,while enhanced in 9cases.No prominent peritumoral edema was detected around the tumors.The average ADC value of the tumors was（1.98×10-3 mm 2 / s）,higher than that of the contralateral normal parenchyma（0.83×10-3 mm 2 / s,t=20.44,P〈0.01）.On pathologic examination,the tumors were composed of specific glioneuronal element,7were simple DNT,17were complex DNT.Conclusion DNT usually presented characteristic appearances on conventional MRI,correlating with specific glioneuronal element of tumors.Significant high ADC value may be helpful to the diagnosis and differential diagnosis of DNT.