FLASH-T2＊WI序列MR磁敏感加权成像对脑海绵状血管瘤的诊断价值

Magnetic susceptibility weighted imaging of FLASH-T_2～*WI sequence in diagnosing cerebral cavernous malformation:a comparison with TSE-T_2WI

目的:通过与TSE-T2WI对比,评价FLASH-T2*WI序列MR磁敏感加权成像(MSWI)在脑海绵状血管瘤(CCM)诊断中的价值和准确性。方法:回顾性分析27例经常规颅脑MR检查、加扫双回波FLASH-T2*WI(TE=15、35ms)磁敏感序列后诊断为CCM的病例,所有病例均经手术病理或临床证实。结果:①所有病灶在SE-T1WI及TSE-T2WI上呈低、中等、高或混杂信号;TSE-T2WI上共检出病灶99个,其中84个有磁敏感伪影,表现为"铁环征"63个(75%),完全低信号21个(25%);双回波FLASH序列TE=15ms加权像上检出病灶234个,TE=35ms共检出423个,病灶均呈显著磁敏感伪影,表现为"铁环征"14个、完全低信号分别为220个(94.02%)和409个(96.69%);三加权像上病灶内伪影的表现、大小及对比噪声比有显著差别。②19例病灶内的伪影区经病理证实17处为机化的血栓、含铁血黄素沉积及脑胶质增生。结论:"铁环征"或磁敏感伪影是诊断CCM的重要依据;FLASH-T2*WI序列MSWI对CCM的显示能力、准确性优于TSE序列,适当延长TE对CCM显示效果更好。

Objective： To evaluate the value and accuracy of magnetic susceptibility weighted imaging （MSWI） of FLASH- T2＊WI sequence in the diagnosis of cerebral cavernous malformation （CCM） by comparing with TSE-T2WI. Methods： Twenty- seven patients performed with routine MR examination and dual echo FLASH-T2＊WI （TE=15, 35ms） were analyzed retrospec- tively, all cases were confirmed by pathology or other methods. Results： （1All lesions on SE-TIWI and TSE-T2WI were depicted iso-, hyper-, hypo- or heterogeneous signal intensity, 99 lesions were detected by TSE-T2WI, and magnetic susceptibil- ity artifact（MSA） was found in 84 lesions, 63（75%） of them were depicted as ＂hoop sign＂ and 21（25%） were completely hypo- intense; 234 and 423 lesions were found orderly by dual echo FLASH-T2＊WI （TE=15, 35ms）, MSA was present in all focus, 14 lesions were described as ＂hoop sign＂ and 220（94.02%）, 409（96.69%） were absolutely hypo-intense, there were great difference of image signs, size and contrast to noise ratio （CNR） of MSA between the three weighted imagings. （2）Seventeen le- sions of 19 patients with ＂hoop sign＂ or MSA were confirmed as thrombus, hemosiderin or gliosis by pathology. Conclusion： ＂Hoop sign＂ or MSA was one of the important signs for CCM, MSWI of FLASH-T2＊WI sequence is helpful in the diagnosis of CCM, and FLASH with long rITE is better than short TE to show small lesions.