Final answer:
On a CT scan, an acute subdural hematoma appears as a high-density crescent adjacent to the skull, may cause a midline shift, and requires urgent medical attention.
Step-by-step explanation:
An acute subdural hematoma on a computed tomography (CT) scan appears as a crescent-shaped biconvex layer of high density adjacent to the inner table of the skull. This happens because blood is denser than brain tissue and cerebrospinal fluid. On the scan, the hematoma can cause a midline shift due to the increased pressure and accumulation of blood, which may displace brain structures. This is often associated with a fracture in the skull such as the pterion, which, when damaged, can lead to an arterial rupture and the subsequent hematoma.
Additionally, acute subdural hematomas can cause compression of the ventricular system and local brain tissue. The appearance of an acute subdural hematoma on a CT scan is critical for diagnosing and guiding the treatment plan, which often requires urgent medical attention to reduce intracranial pressure and to prevent further brain injury or death.