"Post-hydrocephalus corpus callosum damage is seen both in the setting of, and following treatment for, long-standing hydrocephalus. The exact pathophysiology remains to be fully elucidated, but both compression and rapid decompression with resultant changes in morphology have been implicated. Two patterns are identified:"
"The exact mechanisms of the more pronounced scalloping changes seen following decompression, remain to be fully elucidated. Prolonged compression of the corpus callosum against the falx cerebri appears to be necessary, however, it does not appear to be the actual insult that results in eventual damage as pre-decompression the corpus callosum appears thinned but otherwise normal 1-4."
"Not only that, but in the acute post-shunting period swelling and increased T2 signal of the corpus callosum have been observed 5 indicating that it is the rapid inferior displacement of the corpus callosum that results from ventricular size reduction that is the likely inciting event."
"The term corpus callosum impingement syndrome is encountered in the literature for both patterns 6. However, this suggests that the primary aetiology is compression, which does not appear to be the case in the post-treatment changes encountered (see below)."
"Over time these acute changes abate resulting in a thinned, gliotic and distorted appearance with characteristic upper-surfface scalloping 1-4."