目的:分析胼胝体变性的CT和MRI征象.材料与方法:4例胼胝体变性中,3例为急性发病,1例呈慢性过程.4例均行头颅CT扫描,2例行MRI检查,其中1例同时行MRI增强扫描.结果:2例CT示胼胝体膝部和压部呈片状低密度病变,2例病变仅见于膝部.病变的膝部(3例)和压部(2例)呈膨胀性改变,其中1例发病16天后,MRI平扫和强化未见膨胀性改变和异常强化.结论:(1)CT和MRI是诊断胼胝体变性的有效方法,MRI显示胼胝体更全面准确,特别是体部的显示;(2)胼胝体变性CT主要表现是片状低密度灶,急性发病者以膝部和压部常见,可见膨胀性改变,以膝部尤著;(3)晚期胼胝体病变区萎缩,MRI表现为胼胝体中层带状低信号(T1WI),无强化.“,”Objective: To analyze the CT and MRI findings of MarchiafavaBignami disease.Materials and Methods:The clinical features of 4 cases (3 acute form and 1 chronic form) were correlated with the findings on CT (n=4) and MRI (n=2).Results:CT revealed a large lowdensity area in genu and splenium (n=2) or in genu only (n=2). Expansion of the affected genu (n=3) and splenium (n=2) was observed in the early stage. The enlargement and abnormal enhancement of genu in one patient could not demonstrated on both plain and contrastenhanced MRI performed 16 days after onset.Conclusion: (1) Both CT and MRI are effective modalities for diagnosing MarchiafavaBignami disease. MRI shows the corpus callosum, especially its body, more clearly. (2) The main feature of MarchiafavaBignami disease on CT is a lowdensity area. In acute form, enlargement of the splenium, and particularly of the genu, is commonly seen. (3) In the late stage, the lesion becomes atrophied, and abnormal bandshaped low signal zone without enhancement is seen in the middle layer of corpus callosum on T1WI.