Intracranial hemorrhage

Acute hematoma is seen by non-contrast imaging as an area of high density. CT can detect acute intracerebral blood as small as 2mm, due to contrast between high density of blood and low density of surrounding brain.

Epidural hematoma

Defined as bleeding between the inner region of the skull and the dura mater, they are most commonly associated with head trauma.
80% occur with fractures across the middle meningeal artery or a dural sinus and are therefore located in the temporoparietal area.
Classically they are said to present as an alteration of consciousness followed by a “lucid” interval. In actuality, however, only about 30% of cases present classically.
Patients will frequently complain of mental status changes, severe headache, nausea, and vomiting.

CT

Epidural Hematoma

Arrowheads point to the epidural hematoma, which is a collection of blood between the skull and the dura.
Arrow points to shift of midline to the right.

MRI

Epidural Hematoma

Subdural Hematomas (SDH)

Defined as bleeding between the dura and the arachnoid mater, they are usually caused by movement of the brain relative to the skull—as in acceleration-deceleration type injuries—resulting in injury to an artery or vein within or over the brain surface.
Subdurals are more common in patients with brain atrophy such as alcoholics or the elderly. Why?
- The superficial veins of those with brain atrophy are stretched over greater distances and are therefore more prone to rupture with rapid head movement.
Subdurals are more common than epidural hematomas.
They are classified by the time to clinical presentation as acute, subacute or chronic.
Since SDHs are usually caused by injury to venous structures which bleed more slowly, development of clinical signs and symptoms can be delayed.
Clinical presentation will vary depending on the amount of brain injury at the time of trauma and the rate of SDH expansion.

It can range from asymptomatic to altered levels of consciousness or paralysis.

NNNoncontrast CT

CT density of blood is 74 HU consitant with acute blood

Diagnosis: Acute Subdural Hematoma

Acute subdural hematoma covering the right cerebral hemisphere (arrows), more prominent posteriorly.

Patient with history of recent fall.

N-

Diagnosis: Chronic Subdural Hematoma

55 year-old patient with chronic myelogenous leukemia with low platelet count.

A: Left frontal chronic subdural hematoma (arrows) seen as an area of low-density with crescentic inner margin, compressing the adjacent brain.
B: Left frontal subdural hematoma was completely evacuated using burr holes in the skull, but the right chronic subdural hematoma has increased in size in the follow-up CT done 19 days later (arrows) which was also subsequently evacuated.

Subarachnoid hemorrhage (SAH)

Defined as blood within the CSF subarachnoid space, it likely results from tears of small subarachnoid vessels—either spontaneously or post trauma.
SAHs classically present as atypical headaches which are abrupt in onset and severe (“worst headache of my life”).
Spontaneous subarachnoid hemorrhages are most often caused by rupture of arterial aneurysms which releases blood directly into the CSF. The most common cause of SAH overall is trauma.
This rapidly increases intra cranial pressure.

Subarachnoid Hemorrhage / Subdural Hemorrhage

Arrowheads point to subarachnoid blood in the sulci and SA space.
Black arrow points to subdural blood.
White arrow points to shift of midline to right.

Intracerebral Hemorrhage (ICH)

Intra cerebral hemorrhage is usually derived from arterioles or small arteries.
The most common causes of ICH are hypertension, trauma, bleeding diatheses, amyloid angiopathy, illicit drug use, and vascular malformations.
Defined as hematomas deep within the brain tissue, they may be caused by shearing or tensile forces that stretch and tear small- caliber arterioles (traumatic) or ruptured micro-aneurysms (chronic uncontrolled hypertension).
While the clinical effects vary, many patients exhibit impaired consciousness.

Diagnosis: Acute Intracerebral Hematoma

Acute intracerebral hematoma within the right temporal lobe (arrow) with surrounding edma (E).

60 year-old patient with melanoma. Hemorrhage is from metastatic tumor bleed. Acute hematoma is seen by non-contrast imaging as an area of high density. CT can detect acute intracerebral blood as small as 2mm, due to contrast between high density of blood and low density of surrounding brain (arrows).

Intraventricular hemorrhage

Shunt induced Intraventricular Hemorrhage

Arrow points to shunt.
V: Intraventricular blood
Arrowheads point to normal CSF density.