椎管内髓外囊性病变的MRI诊断及鉴别

MRI diagnosis and differential diagnosis of intraspinal extramedullary cysts

目的探讨椎管内髓外囊性病变的MRI表现。方法回顾分析30例经手术病理证实的椎管内髓外囊性病变的MRI及相关临床资料。结果 30例患者中脊膜囊肿15例,肠源性囊肿8例,胚胎性囊肿5例,囊性神经鞘瘤2例。脊膜囊肿中硬膜外囊肿(Ⅰa)3例,骶管脊膜囊肿(Ⅰb)10例,神经根鞘囊肿2例(Ⅱ);均表现为有薄壁包裹长T1长T2信号,1例神经根鞘囊肿中可见神经纤维走行。肠源性囊肿位于脊髓腹侧的髓外硬膜下间隙,其中颈段椎管5例,颈胸段1例,胸段2例,平扫表现为长或等T1、长T2信号,3例见"脊髓嵌入征"。胚胎性囊肿表现为不同程度T1WI高信号,腰骶段常见。囊性神经鞘瘤强化边缘不规则。结论椎管内髓外囊性病变在发病部位、形态、MRI信号特点及强化等方面有一定特点。

Objective To study the MRI manifestations of intraspinal extramedullary cysts. Methods The MRI findings and clinical data of 30 patients with intraspinal extramedullary cysts proved by surgery and pathology were analyzed. Re- suits Fifteen lesions of 30 patients were meningeal cysts, 8 were enterogenous cysts, 5 were embryonic cyst and 2 were cystic schwannoma. Among spinal meningeal cysts, 3 were intraspinal epidural cyst （ I a）, 2 were meningeal cysts within sacral canal, and 2 were nerve root sheath cysts（ 11 ）. All spinal meningeal cysts showed prolong T1 and T2 signal and with thin capsule and nerve fiber through the cysts were seen in one case. Enterogenous cysts located in ventral spinal cord and intradural extramedullary space, among which 5 cases occurred in the cervical segment, 1 lesion in the junction of cervical and thoracic segments and 2 lesions in the thoracic segments. All the lesions with well-defined margin presented with long T1 and long T2 signal in plain MRI and had no enhancement on the postcontrast images. 3 lesions showed sign of spinal cord incuneation. Embryonic cyst presented high signal on both T1WI and T2WI and occurred in lumbosacral segments were commonly seen. Cystic schwannoma demonstrated irregular borderline enhancement. Conclusion MRI can make the correct preoperative diagnosis according to the appearance, signal features and preferable location of intraspinal extramed- ullary cysts.