儿童弥漫性中线胶质瘤伴H3K27M改变的MRI表现

目的  探讨儿童弥漫性中线胶质瘤伴H3K27M改变的MRI特点。方法  回顾性分析上海市儿童医院2017年7月~2021年11月经手术病理证实为儿童弥漫性中线胶质瘤伴H3K27M改变的7例患儿临床及影像资料，所有患儿术前均行MRI检查，对肿瘤MRI特征进行分析。结果  7例均为单发病灶，其中5例位于脑干，1例位于丘脑，1例位于胸髓。4例肿瘤形态不规则，2例呈类圆形，边界均较清楚；1例胸髓病变呈长条形，边界不清。2例出现囊变、坏死，均未见出血。6例肿瘤实性成分T1WI呈低信号、T2WI呈稍高-高信号、T2-FLAIR呈高信号；1例胸髓内肿瘤实性成分T1WI呈稍高信号、T2WI呈高信号、T2-FLAIR呈高信号。6例肿瘤实性成分扩散加权成像扩散受限，1例未见明显扩散受限。增强扫描，6例呈明显不均匀强化，其中3例呈环形强化，2例呈结节状强化，1例呈斑片状强化；1例未见明显强化。7例未见瘤周水肿，均未发现远处转移及脑脊液播散。结论  儿童弥漫性中线胶质瘤伴H3K27M改变的MRI表现具有一定的特征性，综合分析其发病部位、扩散有无受限和强化方式及范围等情况，有助于提高对该病影像学诊断与鉴别诊断水平。

MRI features of pediatric diffuse midline glioma,H3K27-altered

  Objective  To investigate the MRI features of pediatric diffuse midline gliomas, H3K27-altered.  Methods  A retrospective study was carried out to analyze 7 pediatric patients of diffuse midline gliomas, H3K27-altered confirmed by surgery and pathology in Shanghai Children's Hospital from July 2017 to November 2021. The clinical and MRI data were abstracted from their electronic medical records. All the 7 patients underwent plain and enhanced MRI scan before operation, and the MRI features of the tumors were observed and analyzed.  Results  All the patients showed a unilateral mass. 5 cases were located in brainstem, 1 case was located in thalamus, and 1 case was located in thoracic spinal cord. 4 cases were irregular and 2 cases were round-like with clear boundaries, but the case in thoracic spinal cord was strip with unclear boundary. 2 cases had cystic or necrosis, and all cases had no hemorrhage. In 6 cases, the solid components of tumor showed low signal on T1WI, slightly-high signal on T2WI and high signal on T2- FLAIR; The solid components of thoracic spinal cord tumor showed slightly higher signal on T1WI, high signal on T2WI and high signal on T2-FLAIR. 6 cases of DWI had diffusion restriction and 1 case had no diffusion restriction.MRI enhanced scans showed 6 cases had obvious uneven enhancement and 1 case had no obvious enhancement, of which 3 cases showed circular enhancement, 2 cases showed nodular enhancement and 1 case showed patchy enhancement. There was no obvious edema around the tumors. Distant metastasis and cerebrospinal fluid dissemination were no found in all cases.  Conclusion  There are certain MRI features of pediatric diffuse midline gliomas, H3K27-altered. The location of the tumor, diffusion restriction, and the mode and scope of enhancement will help to improve the level of imaging diagnosis and differential diagnosis of the disease.