The CT Epidural vs Subdural Hematoma Diagnosis Tips
The CT Epidural vs Subdural Hematoma Diagnosis Tips Trauma to the head often raises immediate concern about possible intracranial hemorrhages, with epidural and subdural hematomas being two critical types that require prompt diagnosis and treatment. Despite sharing some clinical features, these hematomas differ significantly in their origin, presentation, and imaging characteristics. Recognizing these differences is essential for clinicians to initiate appropriate interventions swiftly.
An epidural hematoma (EDH) occurs when blood accumulates between the dura mater and the skull, typically due to arterial bleeding, often from the middle meningeal artery. It frequently results from skull fractures, especially in the temporal region. Patients with EDH may initially present with a brief loss of consciousness, followed by a period of lucidity, and then rapid neurological deterioration. The classic “talk and deteriorate” pattern underscores the urgency in diagnosis. Conversely, subdural hematomas (SDH) develop beneath the dura mater, within the subdural space, often from tearing bridging veins due to acceleration-deceleration injuries. Symptoms tend to be more insidious, with gradual onset of confusion, headache, and worsening neurological signs over hours to days.
Computed tomography (CT) remains the cornerstone for diagnosing these hematomas. In EDH, the hallmark is a biconvex, lens-shaped hyperdense lesion that does not cross suture lines due to the dural attachments at sutures. Its shape reflects the confined nature of the epidural space. Often, there is a characteristic “swelling” of the underlying skull fracture site, and a midline shift can be evident if the hematoma is large.
In contrast, SDH appears as a crescent-shaped, or concave, hyperdense or isodense collection that extends over a hemisphere, often crossing suture lines but typically confined by dural reflections such as the falx cerebri. This shape results from blood pooling beneath the dura and can be more diffuse. Chronic SDH may appear hypodense due to liquefaction of blood, making differentiation more challenging.
Clinical context and mechanisms of injury greatly aid diagnosis. A linear skull fracture with rapid neurological decline suggests EDH, especially if a lucid interval is observed. Conversely, a slow onset of symptoms after a minor fall in elderly patients or those on anticoagulants points toward SDH. Additionally, the presence of midline shift, brain compression, and the size and shape of hematomas on CT help determine urgency and surgical planning.
In summary, understanding the distinctions between epidural and subdural hematomas on CT imaging—biconvex versus crescent shape, skull fracture association, and crossing suture lines—is critical. Timely recognition of these features, combined with clinical history, can significantly improve patient outcomes by guiding rapid intervention.
