儿童胚胎发育不良性神经上皮肿瘤的影像诊断

Imaging diagnosis in pediatric patients with dysembryoplastic neuroepithelial tumor

目的探讨儿童胚胎发育不良性神经上皮肿瘤(DNET)CT和MRI的影像诊断。方法选取上海市儿童医院2010年1月~2019年12月7例经手术病理证实的DNET术前患儿的影像学资料,包括颅脑MRI平扫、增强和其中4例MRS检查,6例CT平扫影像进行回顾性分析。结果病变均单发,颞叶2例,额叶2例,枕叶2例,小脑半球1例。4例类圆形,2例楔形,1例不规则形。CT表现5例病灶呈等或稍低密度,1例呈等低密度伴片状钙化灶,1例邻近颅骨受压骨质略变薄。7例MRI平扫T 1WI序列呈低信号或稍低信号,T 2WI序列呈高信号,T 2-FLAIR序列呈稍高信号。在T 2-FLAIR序列中,2例可见边缘呈高信号的“环征”及1例呈“倒三角征”。DWI均未见明显弥散受限征象,增强T 1WI 6例无明显强化,1例呈轻度环形强化。增强T 2-FLAIR 3例,1例边缘不规则强化,2例无明显改变。4例MRS显示病变中心N-乙酰天门冬氨酸(NAA)峰轻微下降、肌酸(Cr)峰和胆碱(Cho)峰无明显变化。结论儿童DNET的CT和MRI表现具有一定的特征性,包括“环征”和“倒三角征”,这些特征有助于做出准确诊断。

Objective To investigate imaging diagnosis of CT and magnetic resonance imaging in pediatric patients with dysembryoplastic neuroepithelial tumor.Methods Imaging findings of 7 pediatric patients with pathologically confirmed DNET of Shanghai Children’s Hospital from January 2010 to December 2019 were retrospectively reviewed in this study.The children were evaluated preoperatively by MR scan,and 4 of them with routines(MRS)and 6 of them with CT scan.Results All focuses of 7 cases were single,located in temporal lobe(2 cases),front lobe(2 cases),occipital lobe(2 cases)and cerebellar hemisphere(1 case).The shapes of the foci presented quasi-circular or oval morphology in 4 cases,wedge shape in 2 cases and irregular shape in 1 case.The image findings with CT scan presented with hypodensity or isodensity in 5 cases,iso-hypodensity with flaky calcification in 1 case and little thinning of the bone was adjacent to the lesion and compressed by the lesion in 1 case.In these 7 cases,they had low signal or slightly low signal on T 1WI,high signal on T 2WI and slightly high signal on T 2-FLAIR.On T 2-FLAIR,peripheral wedge surrounding with high signal ring was found in 2 cases and inverted triangle was seen in 1 case.On diffuse-weighted images(DWI),signs of limited diffusion were not obvious for all the lesions,no obvious enhancement was found in 6 cases and slightly circular enhancement was found in 1 case.3 of 7 cases had taken T 2-FLAIR enhancement scan,1 case showed irregular enhancement of the edge of the lesion and the other 2 cases showed no obvious change of the lesions.On MR spectroscopy(MRS),4 cases showed a slight decline of N-acetylaspartate(NAA)peak and no obvious change in Creatine peak and Choline peak.Conclusion The CT and MR appearances of DNET in pediatric patients have some distinctive characteristics,including ring sign and inverted triangle sign,which is helpful for making an accurate diagnosis.