磁共振成像诊断脑弥漫性轴索损伤

目的　探讨MRI诊断脑弥漫性轴索损伤 (DAI)的方法及价值。方法　回顾性分析 38例临床诊断脑弥漫性轴索损伤患者的MRI资料 ,对其病灶的分布特点、信号特征及不同序列对病灶的显示能力进行统计分析。结果　 38例DAI患者 ,共发现病灶 1338个 ,其中双侧大脑半球皮髓交界处病灶 4 6 9个 ,脑叶白质 4 6 0个 ,基底节区 2 0 2个 ,胼胝体 89个 ,小脑 70个 ,脑干 4 8个。DAI病灶在不同序列中的信号特征不同 ,所显示病灶T1WI为等、低信号 ,T2 WI及FLAIR为高信号 ,SE EPI弥散像为稍高信号或高信号 ,FLASH为显著低信号。病灶在不同序列的显示程度不同 ,FLASH序列能得到显示的病灶 ,SET1WI仅能显示 15 3% ,FSET2 WI能显示 38 9% ,FLAIR能显示 5 4 7% ,SE EPI能显示 6 3 6 %。DAI合并症的显示各序列有着大致相同的特异性 ,但敏感性略有差异。结论　MRI对DAI有非常高的诊断价值 ,不同序列对DAI病灶的显示能力不同 ,FLASH序列能显示常规序列所不能显示的出血灶 ,可作为MRI诊断DAI的首选序列。

Study on diagnosising diffuse axonal injury of brain with MRI imaging

Objective To explore the methods and value of MRI in the diagnosis of diffuse axonal injury(DAI) of brain.Methods Thirty-two patients with DAI showed on MRI images were analyzed retrospectively and were proven by clinical diagnosis.We statistically analyzed the distribution of DAI lesion,characteristic of signal and display rate of DAI lesion with different sequence.Results There were 1338 lesions in thirty-two patient with DAI,of which 469 lesions were seen in the corticomedullary junction,460 in contex,202 in basal ganglia region,89 in cingulated callosum,70 in cerebellar hemisphere and 48 in brain stem.All lesions showed hypo-or isointensity on T 1WI,hyperintensity on T 2WI and FLAIR imaging,slight hypo-or isointensity or hyperintensity on SE-EPI,obvious hypointensity on FLASH.FLASH was the highest sensitivity sequence in MRI.Compared with FLASH,the detection rate of DAI lesion on SE-T 1WI was 15.3%,which on FSE-T 2WI was 38.9%,on FLAIR was 54.7%,on SE-EPI was 63.6%.Conclusion There was high diagnostic value on DAI with MRI imaging.FLASH sequence MRI imaging can display the pinpoint hemorrhagic lesion well which is invisible on conventional methods and consequently it can be an early diagnosis of DAI.