Spontaneous spinal epidural hematoma: findings at MR imaging and clinical correlation.

PURPOSE: To evaluate radiologic findings and clinical data in patients with spontaneous spinal epidural hematoma (SSEH). MATERIALS AND METHODS: Thirteen patients (10 men aged 28-71 years; three women aged 40-65 years) with SSEH from 1986 to 1995 underwent magnetic resonance (MR) imaging; six also underwent spinal angiography. Patients with minor trauma, anticoagulant therapy, increased bleeding tendency, or vascular lesions were included. RESULTS: The incidence was estimated to be 0.1 patients per 100,000 patients per year. On MR images, the hematoma was in the anterior (n=8) or posterior (n=4) epidural space or both (n=1). The most common location was the upper thoracic region. T1-weighted images were most useful owing to the pathognomonic signal shift from isointensity with the cord in the early period to hyperintensity in the intermediate stage. Five patients had minor trauma, and four were receiving anticoagulant therapy. CONCLUSION: A rough estimation of the incidence of SSEH is provided,and the results confirm the previously described association with minor trauma and anticoagulant therapy and low frequency of arteriovenous malformations.