自发性脊柱硬膜外血肿的非典型MRI表现与鉴别诊断

The atypical MR imaging findings and differential diagnosis of spontaneous spinal epidural hematoma

目的 提高对自发性脊柱硬膜外血肿非典型MRI表现的认识。方法 对2000年至2008年来院的10例自发性脊柱硬膜外血肿非典型MRI表现进行分析，男7例，女3例；年龄12-64岁，平均32．1岁。所有病例均无明显的外伤史。常规行矢状位T1WI、T2WI，横轴位T2WI，8例行增强扫描。结果 血肿呈梭形、椭圆形，位于脊髓的侧后方或后方的硬膜外腔。血肿发生于颈段5例，胸段3例，胸腰段2例。病灶与脊髓之间有一低信号线状影相隔，尤以T2WI显示最佳。血肿范围多在2-4个椎体，总量约5-10ml，均值为（6．9±1．8）ml。在T1WI图像上，6例表现为等信号，4例表现为高信号；在T2WI图像上，6例表现为混杂高信号，4例表现为混杂低信号。5例血肿壁边缘轻度强化。6例血肿MRI信号比较典型。4例血肿MRI信号不典型。活动性出血以及血肿因时间而演变是血肿征象不典型的原因。本组4例误诊的原因：（1）活动性出血所致血肿征象不典型；（2）血肿位于狭窄的腔隙内；（3）临床上无外伤史。结论 根据血肿演变的规律，结合起病时间及可能存在活动性出血对血肿MRI信号进行分析，有利于对非典型血肿的诊断和鉴别诊断。

Objective To improve the understanding of atypical MR imaging findings of patients with spontaneous spinal epidural hematoma. Methods MR imaging findings of 10 cases of spontaneous spinal epidural hematoma consisted of 7 males and 3 females were observed in our hospital from 2000 to 2008. The age was ranged from 12 to 64 years old with average age 32.1. All cases had not injury history. The routine T1WI sagittal, T2WI sagittal and transverse planes were performed with MR scanner. 8 cases were examined by MR enhancement scan. Results The hematomas had shuttle or oval shape, were in lateral posterior or posterior epidural space, including 5 cases at cervical vertebral segment, 3 cases at thoracic vertebral segment, and 2 case at thoracic and lumbar vertebral segment. There was a low signal septum between spinal cord and hematoma on T1WI and T2WI, especially clear on T2WI. The hematomas covered 2 to 4 vertebral bodies mostly, the gross were ranged from 5 ml to 10 ml with average （6.9±1.8） ml. T1-weighted images showed isointensity （6 cases） to spinal cord and high-intensity（4 case）; T2- weighted images revealed mixed high-intensity （6 cases） and mixed low-intensity （4 case）. The wall of hematoma was enhanced in 5 cases on MRI enhancement scan. The hematoma signal was typical on 6 cases and atypical on 4 cases. The cause of atypical MR imaging findings of hematomas were active bleeding and the signal intensity of the hematoma varied with the hematoma age. The reasons of four misdiagnosis cases were： （1） Active bleeding result in atypical MR imaging findings of the hematoma; （2） The hematoma located in the narrow diastema; （3） No traumatic history on clinic. Conclusion It is useful for diagnosis and differential diagnosis of hematoma on the analysis of the MR signal intensity based on the change of the hematoma and the hematoma age and active bleeding.