Hydrocephalus ex vacuo with some extensive white matter atrophy!
Hydrocephalus ex vacuo, also known as compensatory enlargement of the CSF spaces, is a term used to describe the increase in the volume of CSF, characterised on images as an enlargement of cerebral ventricles and subarachnoid spaces, caused by encephalic volume loss. It can be classified as a communicating hydrocephalus without obstruction to CSF absorption, although we usually do not refer to them as a hydrocephalus. It is usually seen in asymptomatic elderly people as a result of ageing brain with related volume loss, as well in pathological conditions that promote brain shrinkage such as in generalised brain degeneration (Alzheimer disease and leukodystrophies) or due to focal damage (stroke and traumatic injuries). These conditions results in progressive cortical atrophy which subsequently leads to compensatory dilation of the cerebral ventricles known as "hydrocephalus ex vacuo".
