There is a thin-walled cystic lesion located within and expanding the third ventricle, measuring approximately 16 x 21 x 17 mm (L x AP x T). The contents are T1 hypointense (slightly hyperintense relative to CSF) and T2 hyperintense (slightly hypointense relative to CSF). In the posterior aspect of the cystic cavity is well-circumscribed focus of different signal, T1 hyperintense and T2 hypointense. No associated enhancement. The lesion causes obstruction of the Monro foramina bilaterally leading to hydrocephalus, which is overall unchanged compared to the CT from yesterday. Bifrontal EVD are in situ. Small rim of transependymal fluid shift is present. Small amount of blood within the posterior horn of the left lateral ventricle and in a subarachnoid distribution in the frontal lobe are likely related to the EVD placement. The remainder of the brain has unremarkable appearances. No cerebral herniation.