胚胎发育不良性神经上皮瘤的CT和MRI表现

CT and MRI Features of Dysembryoplastic Neuroepithelial Tumors

目的:探讨胚胎发育不良性神经上皮瘤(DNET)的CT和MRI表现。方法:回顾性分析6例经手术病理证实的DNET的MRI和CT资料。6例均行常规MRI检查,其中4例行液体衰减翻转恢复(FLAIR)序列和扩散加权成像(DWI),3例行MR波谱检查。6例中5例行CT平扫。结果:6例中5例为单发,1例为弥漫性。病灶均位于或主要位于皮层区,单发者呈倒三角型表现。肿瘤以囊性成分为主,于CT平扫上均为低密度影,1例可见钙化;其MRI表现为T1WI低信号,T2WI高信号,FLAIR序列上病灶边缘和分隔呈高信号改变,增强扫描示病灶实质结节或分隔有轻度强化,病灶周围均未见水肿。结论:瘤周无水肿、倒三角征和瘤内分隔为PNET的特异性影像学表现,其影像学表现有助于临床诊断和治疗。

Objective：To study the neuroradiologic features of dysembryoplastic neuroepithelial tumors （DNET） on MR and CT. Methods： CT and MRI appearances of 6 patients with surgery and pathology proved DNET were analyzed retrospectively. The parameters included tumor location, size, MR signal intensities, mass effect, degree of contrast enhance ment and intra-tumoral heterogeneity. All of the 6 patients had routine MRI. Of these, 4 patients had FLAIR and diffuse weighted images （DWI）,3 patients had MR spectroscopy. 5 patients had CT without contrast administration. Results： Five DNET patients showed solitary lesion and one patient had diffuse lesions. Typically,DNET located or mainly located in cortical or sub-cortical white matter. The solitary lesion showed a reversed triangle in shape and a predominant cystic component. On CT,all lesions showed low attenuation and one had calcification. On MR images,tumors appeared as low singal intensity on T1WI and high signal intensity on T2WI. At the periphery and septa of the tumor,high signal intensity was assessed on FLAIR images. After contrast administration,mild enhancement could be found at the intra-tumoral solid nodule or septations. No peri-tumoral edema was found. Conclusion： Findings of intra-tumoral ＂ septations＂, reversed triangle in shape and absence of peri-tumoural edema were the characteristic neuro-radiological features of DNET. Imaging examination might be helpful for the diagnosis of DNET.