Corpus callosum impingement syndrome (CCIS) is caused by impingement of the corpus callosal fibers against inferior free margin of the falx cerebri due to longstanding and severe hydrocephalus and stretching of the lateral ventricles. This results in ischemia and eventually atrophy of the neural fibers in corpus callosum. CCIS does not appear to produce any clinical symptoms but recognition of this is crucial to avoid misinterpretation which can lead to unnecessary intervention.
MRI shows severe hydrocephalus and stretching of the lateral ventricles.
Initially, the corpus callosum appears swollen with low signal on T1w sequences and hyperintensity on T2w/FLAIR sequences. Longstanding changes include hyperintensity of the corpus callosum (CC) on T2w/FLAIR as well as volume loss and atrophy which is most pronounced in the rostral portion and body of the corpus callosum. These findings can persist even after decompression of the ventricles.
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