Subdural hematoma is one form of extra-axial collection.

It is typically identified on CT head, which is the first line investigation for concerns over intracranial hemorrhage and unspecified CNS symptomatology.

This MRI illustrates the ability of aging blood on MRI, in this case the collection being subacute in nature.

In this case the subdural hematoma is causing severe mass effect, for which the patient proceeded promptly for surgical evacuation.

Imaging requesting after sound clinical assessment remains the most effective, satisfying and cost effective form of clinical medicine.