Imaging changes in the corpus callosum after ventricular shunting. Case reports and literature review. We report the cases of two patients with ventricular drainage due to idiopathic hydrocephalus and fourth ventricle cys- ticercosis, respectively. A follow-up MRI demonstrated increased volume of the corpus callosum with areas of pro- longed relaxation without restriction on water diffusion sequences. Pathophysiologic theories include direct mechani- cal effects after the catheter insertion, chronic compression of the corpus callosum against the falx due to hydrocephalus, ischemia due to elongation of perforating pericallosal arteries not detected before shunting due to thinning of the corpus callosum, and decompressive changes leading to corpus callosum expansion and interstitial edema. These findings might be related to the history of ventricular shunt and hydrocephalus with no apparent clinical significance. Keywords. Corpus callosum. Hydrocephalus. Magnetic Resonance.