累及胼胝体区肿瘤的MRI鉴别诊断

MRI Differential Diagnosis of Brain Tumors Involving Corpus Callosum

目的：回顾分析累及胼胝体区各类肿瘤的MRI表现特点;探讨MRI的鉴别诊断价值。方法：收集经病理证实或临床诊断的36例胼胝体区肿瘤的临床及MRI资料,分析各类肿瘤的MRI特征,包括MR常规平扫、增强及DWI的特征;病例按2007年WHO分类标准进行分类。结果：36例肿瘤中累及胼胝体嘴部6例,膝部16例,体部14例,压部17例。其中Ⅱ级胶质瘤12例,相对多见,肿瘤边界显示不清,坏死及强化不明显,12例病变胼胝体与正常胼胝体ADC比值的平均值（以＂α＂表示）为1.73,DWI低信号,4例MRS的Cho/NAA比值的平均值（以＂β＂表示）为2.48;Ⅲ级胶质瘤5例,混合信号,多呈＂蜂窝样＂或＂地图样＂强化,5例α为1.49,DWI为低信号为主的高低混合信号,2例β为2.50;Ⅳ级胶质母细胞瘤7例,较多见,多坏死,可伴出血,多呈不规则＂花环样＂或＂结节样＂明显强化,7例α为0.79,DWI实质区高信号伴坏死区低信号,3例β为4.16;淋巴瘤10例,相对较多见,FLAIR呈等信号的肿瘤与周围高信号的水肿分界清楚似＂褐色巧克力饼干沉入白色奶酪中状＂,显著均质强化,10例α为0.78,DWI明显高信号,1例β为1.45;生殖细胞瘤2例,肿瘤边界清楚,多囊变,实质显著均匀强化,α为0.89,DWI明显高信号。结论：胼胝体区肿瘤以胶质瘤（Ⅱ~Ⅳ级）和淋巴瘤多见,MRI表现各有特点,有一定的鉴别诊断价值。

Purpose：To analyze the MRI features of the corpus callosum tumors retrospectively,and explore the differential diagnostic value of MRI.Methods：Confirmed by pathology or clinical diagnosis,clinical and MRI data of 36 cases of corpus callosum tumors were analyzed.Cases were classified according to WHO 2007 edition.Results：Of all the 36 cases of tumors,involving the corpus callosum rostrum were in six cases,the genu in 16 cases,the body in 14 cases,the splenium in 17 cases.Twelve cases of grade Ⅱ glioma were shown with unclear tumor border,and obvious necrosis.Average ADC ratio of the 12 cases lesions and normal corpus callosum（with ＂α＂ said） was 1.73.Average Cho/NAA ratio of 4 cases（with ＂β＂ said） was 2.48.Five cases of grade Ⅲ glioma were shown with mixed-signal,mostly ＂honeycomb-like＂ or ＂map-like＂ enhanced.＂α＂ of them was α 1.49,DWI showed low level signal-based mixed-signal,β of two cases was 2.50.Seven cases of Ⅳ grade glioblastoma were shown with more necrosis accompanied by bleeding,mostly irregular＂rosette-like＂or＂nodular＂ enhanced.α of them was 0.79.DWI showed parenchyma necrotic area with high signal and low signal.β of the three cases was 4.16.Ten cases of lymphoma were shown FLAIR positive signals,such as tumor and surrounding edema with high signal which was seemed like boundaries brown chocolate biscuits into the white cheese in.They were with homogeneous significantly enhancement.α of the 10 cases was 0.78.DWI showed significantly higher signal.β of one cases was 1.45.Two cases germinoma were shown with clearly tumor border,α was 0.89.DWI showed significantly higher signal.Conclusion：Most of the tumors involving the corpus callosum are gliomas（Ⅱ～ⅣGrade） and lymphomas,their MRI features are helpful for differential diagnosis.