Diagnosis is typically by CT scan or MRI. MRIs have greater sensitivity and should be used if there is a high suspicion of<unk>  and a negative CT scan. Differential diagnoses include a transient ischemic attack, intracranial mass, or brain abscess.<unk> s usually appear convex in shape because their expansion stops at the skull's sutures, where the dura mater is tightly attached to the skull. Thus, they expand inward toward the brain rather than along the inside of the skull, as occurs in subdural hematomas. Most people also have a skull fracture.<unk> s may occur in combination with subdural hematomas, or either may occur alone. CT scans reveal subdural or<unk> s in 20% of unconscious people. In the hallmark of<unk> , people may regain consciousness and appear completely normal during what is called a lucid interval, only to descend suddenly and rapidly into unconsciousness later. This lucid interval, which depends on the extent of the injury, is a key to diagnosing an<unk> . File:Epidural hematoma.Nontraumatic<unk>  in a young woman. The grey area in the top right is organizing hematoma, causing midline shift and compression of the ventricle. File:Traumatic acute<unk> .Non-contrast CT scan of a traumatic acute hematoma in the right fronto-temporal area. File:Hematoma.A diagram showing an<unk> .
Epidural hematoma
Subarachnoid hemorrhage
Subdural empyema
Traumatic brain injury
Brain herniation
Brain abscess
Subdural hematoma
Transient ischemic attack