 Elderly patients with marked cerebral atrophy, and secondary widened subarachnoid CSF spaces, can also cause confusion on CT. To distinguish chronic subdural hygromas from simple brain atrophy and CSF space expansion, a gadolinium-enhanced MRI can be performed.Visualization of cortical veins traversing the collection favors a widened subarachnoid space as seen in brain atrophy, whereas subdural hygromas will displace the cortex and cortical veins.Most subdural hygromas that are asymptomatic do not require any treatment.