高场DWI及FLAIR在诊断颅内表皮样囊肿中的价值

目的比较 3.0 T 高场下扩散加权成像(DWI)及液体衰减反转恢复(FLAIR)在诊断颅内表皮样囊肿中的价值.方法 23例常规MRI检查考虑为颅内表皮样囊肿的患者,术前20例加扫了DWI,21例加扫了FLAIR,二者皆使用者18例,其中4例获得了表观扩散系数(ADC)图.结果 22例为表皮样囊肿,其中19例加扫了DWI,均为高信号,边界清楚;病灶(4例)ADC均值为87.1×10-5mm2/s,明显低于脑脊液,但略高于对侧正常脑组织.而FLAIR(20例)上多为等、低或稍高信号影,仅6例为高信号;其中5例病灶边界欠清楚.结论 DWI和FLAIR对表皮样囊肿的定性均有很大价值,但DWI更敏感、准确,且能提供更多的相关信息.

Evaluation of intracranial epidermoid cysts at 3T: DWI vs FLAIR

Objective To compare MR fast fluid-attenuated inversion recovery (FLAIR) with diffusion-weighted imaging (DWI) in the examination of intracranial epidermoid cysts at 3T. Methods 23 patients with intracranial tumors which strongly resembled epidermoid cysts were examined at a 3.0T-system. After conventional MR sequences, DWI was performed in 20 patients, FLAIR in 21 patients and both in 18 patients in which apparent diffusion coefficient (ADC) of 4 cases were measured. Results Twenty-two of these 23 cases were epidermoid cysts. 19 epidermoid cysts showed remarkably hyperintense relative to the brain and CSF with clear margin. The mean ADC of 4 epidermoid cysts was 87.1×10^-5mm²/s, which was significantly lower than that of CSF but slightly higher than that of brain tissues. On FLAIR, only 6 epidermoid cysts showed obviously hyperintense and the others showed isointense, hypointense or slightly hyperintense.Conclusion Both DWI and FLAIR are good tools for evaluating intracranial epidermoid cysts, but DWI is more sensitive, accurate and efficient than FLAIR.