LearningRadiology - Subdural Hematoma

Subacute Subdural Hematoma

Contributed by Weiling Chang, M.D.

Findings: Axial CT scan demonstrates that there is a large R parietal subdural hematoma isodense to the brain. There is associated mass effect with effacement of the right lateral ventricle. Enhanced images delineate the exact margins of the hemorrhage. (see below)

Acute hemorrhage on CT scan appears as bright on CT scan. Over a period of time, the blood becomes darker. Attenuation decreases by 1.5 HU per day on average. There is a point when the blood becomes isodense to the brain parenchyma.
Contrast enhancement can help separate the clot and brain parenchyma since there is enhancement of displaced cortical vessels.
Subdural hematomas are usually crescentic shaped and have the capability of crossing the cranial sutures.
The etiology of a subdural hemorrhage occurs from a tearing of the bridging veins in the subdural space.
Subdural hematomas can be lethal with mortality rates ranging from 50-85%.

Reference:

Osborn, Ann, Diagnostic Neuroradiology, pp 159-161.