椎管内硬膜外出血的影像学诊断和检查策略

Spinalepidural hemorrhage:imaging diagnosis and examination strategy

目的:探讨椎管内硬膜外出血(SEDH)的影像学表现及对其早期诊断的漏诊和误诊原因,提高对早期SEDH的影像诊断水平。方法:回顾性分析我院2014年1月-2018年6月收治的经手术或影像学证实的21例SEDH患者的临床和影像资料(MRI检查21例,CT检查12例)。分析SEDH患者的临床特点及出血部位、形态、信号或密度和继发改变等影像学特征,对比不同影像学技术对SEDH的早期诊断价值。结果:21例患者共检出22个SEDH,其中10例为自发性,11例继发于外伤和穿刺术。急性疼痛和进行性肢体无力为自发性SEDH患者的主要临床首发症状。胸段(33%)为SEDH最好发部位,其次是颈胸段(23.8%)。急性期血肿5个(5/22),CT平扫呈高密度灶,MR T1WI上呈低信号,T2WI上呈高信号;亚急性早期血肿12个(12/22),MR T1WI上呈高信号,T2WI上呈低信号;亚急性晚期血肿5个,T1WI上呈高信号,T2WI上呈高信号。22个SEDH表现为长条线状(40.91%)、长条棒状(13.64%)和梭形(45.45%)三种形态。CT终审报告的漏诊率为75%,以继发性SEDH和以急性疼痛为首发症状的自发性SEDH为主。长条线状和急性期血肿的MRI初步报告漏诊率为100%。同侧的蛛网膜下腔受压变窄,硬脊膜及脊髓受压向健侧移位为重要的间接征象。MR压脂序列T1WI的应用显著降低了对亚急性期SEDH患者的漏诊率(0vs 57.14%,P<0.05)。结论:椎管内硬膜外出血的影像表现有一定规律性,急性期血肿的最佳成像方式是CT,亚急性期血肿的最佳成像方式是MR压脂序列T1WI,多方位仔细观察硬脊膜的移位和蛛网膜下腔的变化等间接征象有助于早期诊断。

Objective:To analyze the imaging findings of the SEDH and the causes of misdiagnosis at the early stage,thus to improve the diagnostic accuracy of imaging examination for SEDH at the early stage.Methods:The clinical and imaging data of 21 cases with SEDH confirmed by surgical operation or imaging exmination in our institution from January 2014 to June 2018 were analyzed retrospectively.All patients underwent MRI exams and 12 of them had CT exams also.For each patient with SEDH,the clinical characteristics and the imaging features including the location,shape,signal intensity or density of hemorrhage and the secondary changes were reviewed.Early diagnostic accuracy of different imaging techniques for SEDH were compared,and the optimal strategy of imaging examination in SEDH were analyzed.Results:In 21 patients with SEDH(totally 22 lesions),10 cases were spontaneous,11 cases were secondary to trauma or puncture.Acute pain and progressive lower limbs weakness were the major first-onset symptoms in the patients with spontaneous SEDH.The thoracic segment(33%)was the most common site of SEDH,followed by the cervicothoracic segment(23.8%).Five acute hemorrhage presented as high density on plain CT images,hypo-intensity on MR T 1WI and hyperintensity on T 2WI.Twelve hemorrhage in early subacute stage presented as hyper-intensity on T 1WI and hypo-intensity on T 2WI.Five hemorrhage in late subacute stage presented as hyper-intensity on T 1WI and T 2WI.SEDH of 21 cases presents as 3 types of shape,including long liner(40.91%),long stick-like(13.64%)and fusiform(45.45%).The rate of missed diagnosis of CT was 75%,mainly in the secondary SEDH and spontaneous SEDH suffered from the acute pain as initial symptom.All long liner hemorrhage and all acute hemorrhage on MRI were missed in the first diagnosis by junior doctors.Compression and narrowing of the ipsilateral subarachnoid space,displacement of the dural and spinal cord were significant indirect signs.The fat saturation sequence significantly decreased the misdiagnositic ratio of subacute SEDH(0 vs 54.17%,P<0.05).Conclusion:There are some specific features in the imaging finding of SEDH.The optimum imaging modalities for acute hematoma and subacute hematoma are CT and fat saturation sequence MR T 1WI respectively.The indirect signs of dural displacement and the subarachnoid space changes would contribute to the early diagnosis of SEDH.