扩散加权成像在超早期脑梗死诊断中的应用

目的　通过临床病例分析 ,探讨磁共振扩散加权成像 (DWI)在超早期脑梗死诊断中的应用价值。方法　对 15例缺血性脑血管病患者 ,在发病后 6h以内 ,急诊行DWI检查 ,观察不同b值时脑实质信号的改变 ,并测量病灶及正常脑组织的表观扩散系数 (ADC)值。结果　超早期脑梗死在DWI上表现为边界清楚的局灶性高信号 ,且信号强度随b值延长而逐渐增强 ,与脑脊液信号变化趋势相反 ,病灶区域局部ADC值下降 ,平均为 (0 .5 5 8± 0 .0 6)× 10 -3 mm2 /s ,较对侧正常值平均降低 45 .3 % ,DWI诊断脑梗死 11例 ,4例DWI阴性病例影像学及临床随访证实 3例为脑血栓形成 ,1例为TIA发作。结论　DWI对于超早期脑梗死的诊断准确、敏感。

Application of MR Diffusion-Weighted Imaging in the Diagnosis of Hyperacute Cerebral Infarction

Objective To evaluate the clinical value of DWI in the diagnosis of hyperacute cerebral infarction by case analysis.Methods DWI were obtained in 15 emergency cases of cerebral ischemia within 6 hours.The signals between the images with different b value were observed and the ADC values in the area of lesion were calculated.Results The changes in DWI of the patients of hyperacute cerebral ischemia were as below:local high signal area with sharp edge,and the longer the b value was,the higher the signal was,which was reverse to that of the trend of CSF.ADC value decrease in the area of lesion,the average ADC was (0.558±0.06)×10^-3mm²/s,reduced by 45.3% compared to that of normal cerebral tissues.Eleven cases of cerebral infarction were diagnosis by DWI.Four cases with negative DWI findings were clinically proven to be other kinds of cerebral ischemia cases.Conclusion In the diagnosis of hyperacute cerebral infarction,DWI is accurate and sensitive.