骶管内蛛网膜囊肿的MRI表现及诊断价值

MRI Diagnosis of arachnoid cysts in sacral canal

目的探讨骶管内蛛网膜囊肿的MRI特点及其诊断价值。方法28例骶管内蛛网膜囊肿经手术病理证实。其中其中男19例,女9例,年龄16～70岁,平均41.6岁。所有病例均行MR检查。结果囊肿位于骶管内,呈卵圆形、不规则形、串珠形。囊肿境界清楚,囊壁薄,囊液信号与脑脊液信号相似,T1WI囊液呈低信号,T2WI囊液呈高信号,其中4例囊肿内可见细条状神经根影,6例增强扫描囊液、囊壁无强化。结论MRI是最好的影像学诊断方法;骶管内蛛网膜囊肿的发生,主要是先天的硬膜缺陷所致。

Object To study MRI characteristics of sacral arachnoid cysts and to evaluate MRI in its diagnosist. Methods 28 patients with sacral arachnoid cyst proved by operation and pathology,19 cases of male,9 cases of female;the age ranged from 16 to 70 years old,average age is 41.6. All cases were performed on MR examination. Results The shape of cysts were elliptic,irregular and string shape. The edge of cysts is clear and wall of cysts is very thin. MR signal in tensity of fluid in sacral arachnoid cyst exhibits similarity to cerebrospinal fluid,which shows uniform low signal in T1WI and high signal in T2WI. There are 4 cases thin strip nerve root can be found through the cysts in T1WI and T2WI. The antrast enhancement was wade in 6 cases and there no any enhancement both in content and wall of cyst. Conclusion MRI allows us to predict better the arachnoid cyst in sacral canal,and the cyst seems to arise as a result of congenital defeet of thecal dura.