弥散加权成像结合表观弥散系数界定脑梗死患者缺血半暗带的价值

目的应用弥散加权成像（DWI）结合表观弥散系数（ADC值）分析超急性、急性期、亚急性期缺血性脑梗死患者半暗带的范围和演变过程。方法测量38例（超急性期10例、急性期16例、亚急性期12例）脑梗死患者梗死灶中央区、边缘区、周围区平均ADC值，计算相对ADC（rADC）值。对不同分期、不同区域进行统计学分析。结果超急性期、急性期缺血灶平均ADC值（3．83±0．89）×10^-4mm。／s、（4．92±0．18）×10^-4mm^2／s，明显低于对侧正常区域（8．29±0．54）×10^-4mm^2／s、（7．86±0．63）×10^-4mm^2／s（P〈0．05），而亚急性期病灶区与对侧正常区域无明显差异（P〉0．05）。超急性期、急性期、亚急性期病变中央区rADC值减低最明显，病变外周区（边缘区和周围区）rADC值下降少于中央区，从梗死中心到周围rADC呈阶梯状升高。结论超急性期、急性期脑梗死缺血灶周边区存在缺血半暗带；DWI结合ADC能快速准确诊断超急性、急性期脑梗死，反映脑组织损伤程度，判断缺血半暗带的范围。

The value of diffusion weighted imagining combined with apparent diffusion coefficient in defining the ischemic penumbra in cerebral infarction

Objective To analyze the infarct ischemic penumbra （IP） range and the evolution process in hyper-acute, acute and sub-acute cerebral infarction by apparent dispersion coefficient （ADC） and diffuse weighed imaging （DWI）. Methods 38 patients （10 hyper-acute, 16 acute and 12 sub-acute cerebral infarction） were examined by DWI, and the average ADC value , relative ADC （rADC） in center and periphery and adjacent to the lesion were calculated. Statistical analy- sis was performed by SPSS 14.0 software packet within each group and among different groups. Results Hyper-acute, acute ischemic lesion mean ADC value （3.83± 0.89） ×10^-4 mm^2/s, （4.92 ±0.18） × 10^-4 mm^2/s, significantly lower in the contralateral normal area （8.29 ± 0.54）× 10-4 mmZ/s, （7.86 ± 0.63） ×10^-4 mm^2/s（ P 〈 0.05） ,while the sub-acute phase and contraateral lesions had no significant difference in the normal region （ P 〉 0.05 ）. Hyper-acute, acute, sub-acute lesions central part rADC reduced most significant, lesion in peripheral zone （edge of the area and the surrounding area） rADC value drops below the central area, from the center to the surrounding rADC infarction stepwise increased. Conclusion Hyper-acute, acute cerebral ischemic lesions surrounding area exist penumbra; DWI combined with ADC can quickly and ac- curately diagnose hyper-acute, acute cerebral infarction, reflecting the extent of brain damage, to determine the scope of the ischemic penumbra.