What classic CT findings appear on a head CT for a subdural hematoma?
The classic appearance of an acute subdural hematoma is a crescent-shaped homogeneously hyperdense extra-axial collection that spreads diffusely over the affected hemisphere. As the clot starts to retract the density increases typically to >50-60 HU and is thus hyperdense relative to the cortex 4.
What does a subdural hematoma look like on CT?
On noncontrast CT scan, an acute subdural hematoma appears as a hyperdense (white), crescent-shaped mass between the inner table of the skull and the surface of the cerebral hemisphere (see the images below).
How can you tell the difference between a subdural hematoma and an epidural CT?
Subdural hematomas are concave toward the brain and unlimited by suture lines, as opposed to epidural hematomas, which are convex toward the brain and restricted by suture lines. Rarely, a subdural hematoma appears lens shaped (ie, more like an epidural hematoma).
How does hematoma appear on CT?
Pre-contrast CT scan is the imaging procedure of choice to evaluate intracerebral hemorrhage. Acute hematoma is seen by pre-contrast CT imaging as an area of high density. CT can detect acute intracerebral blood as small as 2 mm, due to contrast between high density of blood and low density of surrounding brain.
How do you describe CT findings?
How do we describe abnormalities on CT? When describing findings on CT, we use words that refer to how dense the abnormality is in relation to a reference structure. Reference structures include bone, gray matter, white matter, CSF, fat, air etc.
Where is subdural hematoma found?
A subdural hematoma is a type of bleed inside your head. More precisely, it is a type of bleed that occurs within the skull of head but outside the actual brain tissue. The brain has three membranes layers or coverings (called meninges) that lay between the bony skull and the actual brain tissue.
What does an epidural hematoma look like on CT?
In almost all cases, extradural hematomas are seen on CT scans of the brain. They are typically bi-convex (or lentiform) in shape, and most frequently beneath the squamous part of the temporal bone. EDHs are hyperdense, somewhat heterogeneous, and sharply demarcated.
What appears hyperdense in CT?
Hyperdensity at CT was due to the high hemoglobin content of retracted clot or sedimented blood. The various patterns seen can be related to sequential changes occurring in blood following hemorrhage. Relative hyperdensity and its variations seen on precontrast scans are useful diagnostic signs of recent hemorrhage.
What does a subdural hematoma look like?
Therefore, a subdural hematoma is located between the dura and arachnoid layers of the meninges. It appears as a convex, crescent-shaped hemorrhage on head imaging. Subdural hematomas are typically caused by an accelerating-decelerating type injury that leads to shearing stress of the bridging veins.
What is the role of CT in the diagnosis of subdural hemorrhage?
In the vast majority of cases, CT scans are sufficient to make the diagnosis and manage these patients. Contrast is sometimes helpful if there is the concern of subdural empyema, of the presence of a small isodense subdural, or to try and distinguish enlargement of the extra-axial CSF space from a chronic subdural hematoma.
What is subacute subdural hematoma (SDH)?
Subacute subdural hematoma here was defined as a nonoperated case with acute subdural hematoma, accompanied by subacute exacerbation 1-3 weeks after head trauma. The time from the injury to the onset averaged 13.7 days.
How are subdural haematomas (SDHS) diagnosed?
Common sites for subdural haematomas are frontoparietal convexities and the middle cranial fossa. Isolated interhemispheric/parafalcine subdural haematomas are seen more frequently in children and are common in cases of non-accidental trauma. In the vast majority of cases, CT scans are sufficient to make the diagnosis and manage these patients.