磁共振扩散加权成像在脑梗死诊断中的应用

目的研究不同时期脑梗死扩散加权成像的差异，探讨DWI及表观扩散系数值对脑梗死的诊断价值。方法对80例脑梗死患者进行常规MRI及DWI检查，测量不同时期梗死病灶ADC值及相对rADC值，比较各期rADC值的差异。结果@DWI对超急性期、急性期脑梗死梗死灶显示较常规MRI成像更加准确、清晰。②超急性、急性期rADC最低，分别为（63．13±6．39）％、（67．75±7．90）％，亚急性期时rADC逐渐升高，甚至出现假正常化现象，慢性期时明显高于正常水平，rADC与脑梗死病程具有显著相关（r=0．866，P〈0．001）。结论DWI对超急性期及急性期脑梗死诊断敏感；与ADC值联合应用，有助于及时准确判断脑梗死的分期和病理生理改变，为临床治疗及预后判断提供依据。

Application of MR Diffusion Weighted Imaging in Cerebral infarction

Objective To investigate the difference of MR diffusion weighted imaging（DWI） value in cerebral infarction and to explore the diagnostic value of DWI and apparent diffusion coefficient （ADC） in different stages of cerebral infarction. Methods Eighty patients with cerebral infarction were examined by conventional and diffusion weighted imaging（DWI） on 1.5T MRI device. The apparent diffusion coefficient（ADC ） and the relative ADC（rADC ） were calculated. Results Super-acute and acute cerebral infarction on DWI were displayed more accurate and clearer than that of the conventional MRI. The rADC in super-acute and acute stage was minimized,the super-acute type was （63.13 ± 6.39）% and the acute type was（67.75 ± 7.90）%, and increased progressively as time pass and some appeared as ＂pseudonormal＂ values approximately, thereafter,the rADC became greater than normal in chronic stage. There was positive correlation between rADC and time （r = 0.866, P 〈 0. 001 ）. Conclusion DWI is more sensitive than conventional MRI in diagnosing Super-acute and acute cerebral infarction. Combining DWI and ADC can be helpful to assess stage precisely and pathophysiological phase of infarction, and to provide the evidence in guiding the treatment and judging the prognosis in infarction.