The CT Epidural vs Subdural Hematoma Differences
The CT Epidural vs Subdural Hematoma Differences Trauma to the brain can result in various types of hematomas, which are localized collections of blood outside of blood vessels caused by injury. Two common intracranial hematomas identified on imaging studies are epidural and subdural hematomas. Although they share some similarities, they differ significantly in their pathophysiology, clinical presentation, imaging characteristics, and management.
An epidural hematoma occurs when blood collects between the dura mater—the outermost layer of the meninges—and the skull. This type of hematoma is often caused by traumatic injury leading to arterial bleeding, most commonly from the middle meningeal artery. Because arteries carry blood at higher pressures, epidural hematomas tend to expand rapidly, often causing a swift increase in intracranial pressure. Patients may experience a characteristic “lucid interval,” where they temporarily regain consciousness after the injury before neurological deterioration occurs. Symptoms include headache, vomiting, confusion, and, in severe cases, coma.
In contrast, a subdural hematoma involves bleeding between the dura mater and the arachnoid mater, which is a layer closer to the brain tissue. Subdural hematomas are primarily venous in origin, often resulting from tearing of bridging veins that drain blood from the brain into the dural sinuses. Because venous bleeding typically occurs at lower pressure, subdural hematomas usually develop more gradually, allowing some patients to be asymptomatic or have mild symptoms initially. As the hematoma enlarges over days or weeks, it can cause increased intracranial pressure, leading to headache, drowsiness, weakness, or neurological deficits.
Imaging studies, particularly computed tomography (CT) scans, are crucial in differentiating these hematomas. An epidural hematoma appears as a biconvex (lens-shaped) collection that does not cross suture lines, making it confined to a specific region of the skull. It often shows a hyperdense (bright) appearance in the acute phase. On the other hand, a subdural hematoma has a crescent-shaped appearance that can extend across suture lines, reflecting its potential to spread over larger areas of the brain surface. The density of the hematoma on CT can vary depending on its age—acute subdural hematomas are hyperdense, while chronic ones may appear hypodense (darker).
Management strategies differ based on hematoma type, size, and the patient’s neurological status. Epidural hematomas often require urgent surgical intervention, such as craniotomy or burr hole evacuation, to prevent brain herniation and further neurological deterioration. Subdural hematomas may also need surgical removal, especially if they are large or causing significant mass effect, but small or chronic subdural hematomas might be managed conservatively with close monitoring.
Understanding these differences is essential for prompt diagnosis and appropriate treatment. Recognizing the typical clinical features and radiological appearances allows healthcare providers to swiftly differentiate between epidural and subdural hematomas, ultimately improving patient outcomes and reducing the risk of long-term neurological deficits.
