儿童胼胝体发育不全的MRI诊断

MRI of Agenesis of the Corpus Callosum in Children

目的阐述脑胼胝体发育不全及相关畸形的ＭＲＩ表现，并提出在不同方位上观察的重点内容。方法胼胝体发育不全的小儿患者１１例，ＭＲ成像仪为１０Ｔ扫描机，采用矢状面、横断面和冠状面成像，横断面为ＳＥＴ１和ＴｕｒｂｏＳＥＴ２ＷＩ，矢状和冠状面成像均为Ｔ１ＷＩ。正常对照组２０例，测量胼胝体的前后径、大脑额枕径及两者比例，其结果和病变组进行比较。结果胼胝体完全缺如２例，部分发育不全９例，胼胝体发育不全的ＭＲ征像包括：胼胝体变小或缺如（Ｐ＜００１）；三脑室扩大、升高并伸入半球间裂；侧脑室扩大，体部平行分离，前角分离；大脑前动脉、大脑内静脉和Ｇａｌｅｎ’ｓ静脉位置和形态异常；边缘系统发育畸形。另外，尚可见颅内脂肪瘤、脑灰质异位、多微脑回畸形和脑回肥厚。结论胼胝体发育不全是一种合并神经系统其他不同程度畸形的复合畸形，ＭＲＩ成像不仅能够明确胼胝体发育不全本身的畸形，而且还能够同时显示边缘系统的异常改变和并发的其他神经系统畸形，是该类疾病最佳的检查方法。

Purpose To evaluate the MR appearance of ACC and its associated maldevelopment,and give us the important signs on three different oriented secions.Methods We retrospectively reviewed the records of 11 patients who underwent MR imaging,with particular attention to its associated malformation.MR imaging was performed with 1.0T Magnetom Impact.Axial,coronal,sagittal planes were routinely obtained.T 1-weighted images were made on all planes,and Turbo spinecho T 2-weighted images only on axial planes.The maximal anterioposterior diameter of the corpus callosum and maximal frontooccipital diameter of the cerebrum were measured in 20 healthy volunteers,the results were compared with those of the patients.Results The corpus callosum was absent totally in 2 patients,and partial ACC was found in 9 patients.MRI features of ACC included:small or absent corpus callosum( P <0 01);dilation and elevation of the third ventricle into the interhemispheric fissure;enlarged lateral ventricles,nearly parallel and separated bodies of lateral ventricles;straightened and separated frontal horns;abnormalities of anterior cerebral arteries,internal cerebral veins and Galen’s veins in morphology and location;associated malformations of the limbic system.Additionally,lipoma,gray matter heterotopias polymicrogyrias,and macrogyrias were also found.Conclusion Agenesis of the corpus callosum(ACC) is a complex malformation that has been associated with varying degrees of the maldevelopment.MR revealed not only the anomalies intrinsic to corpus callosum but also the associated malformations of the limbic system and other malformations of the brain,therefore MRI is the best method in the diagnosis of ACC and its associated abnormalities.[