DWI与ADC值在不同时期脑梗塞的临床应用研究

目的：探讨三向同性扩散加权成像（DWI）表观扩散系数图（ADC mapping）在不同时期脑梗塞的诊断以及在判断脑梗塞的转归和分期中的应用价值。方法：应用单次激发平面回波三向同性扩散加权成像（DWI）和常规MRI平扫对90例脑梗塞患者进行检查,其中超急性期30例（起病至检查前时间〈6 h）,急性期30例（7～72 h）,亚急性期30例（3～10 d）,在ADC图上测量梗塞灶ADC平均值,同时测定对侧相应区域ADC值,并由此计算相对ADC值（rADC=病变区ADC/对侧相应区域ADC×100%）,分析梗塞不同时期rADC值随时间变化的规律。结果：超急性期、急性期脑梗塞灶在DWI上表现为高信号,其ADC值较对侧相应区域明显下降,平均ADC值分别为超急性期：0.342×10^-3mm^2/s,急性期：0.462×10^-3mm^2/s,对侧相应区域ADC值分别为超急性期：0.744×10^-3mm^2/s,急性期：0.817×10^-3mm^2/s。超急性期,急性期病灶rADC值最低,分别为超急性期：45%,急性期：59%,随时间延长rADC由低到高,即rADC值与时间具有显著相关性。结论：梗塞灶ADC值具有特征性演变规律,结合DWI、T2WI,ADC图可以对脑梗塞进行分期诊断,还可以动态观察进行疗效评价。

Aclinic Application Research on DWI and ADC in Different stages Cerebral Infarction

Objective： To study the roles of is＇otropic diffusion weighted imaging and apparent diffusion colficients （ ADC ） mapping in diagnosing cerebral infarction , monitoring the development of cerebral infarction and defining the infarction stages. Methods：90 patients with cerebral infarction （ 30 hyperacute 〈 6 hours 30 acute 7-72 h ours 30 subacute 3-10 days ） were imaged with both conventional MRI and single- shot echoplanar isotropic diffusion weighted imaging . The average ADC, relative ADC on ADC mapping and calculate rADC . Analyze rADC became rule with time at Brain infarction. Result： Hyperacute and acute infaracts appeared as areas of hyperintensing on DWI, and their average ADC was significantly depressed compared with that of homologous contralatera tissue. （ hyperacute ： 0. 342× 10^-3 mm^2/s, acute： 0. 462×10^-3 mm^2/s ）, versus（ hyperacute： 0. 744 ×10^-3 mm^2/s,acute：0. 817×10^-3 mm^2/s ）, rADC in hyperacute and acute stage was minized, （ hyperacute： 45% , acute：59% ） and increasd progressively as time passed. Thereafter, rADC became greater than normar in chronic stage. There was posive correlation between rADC and time. Conclusion： Combined with DWI, T2WI, and ADC, hyperacute and acute stage of cerebral infarction could be rapidly and accurately. ADC values have specific evolving rule on ADC mapping.