磁共振弥散张量成像在脑梗死不同时期的诊断价值

目的探讨磁共振弥散张量成像（DTI）在脑梗死不同时期的演变规律及临床诊断价值。方法对55例不同时期脑梗死患者（病例组）及20例健康志愿者（对照组）行磁共振成像（MRI）检查，分析DTI图像、各向异性分数（FA）和表面弥散系数（ADC）的变化，并比较病例组不同部位脑梗死与对照组相应部位脑组织FA值的变化特点。结果患者不同梗死部位与对照组平均FA值比较差异有统计学意义（P〈0．05）。脑梗死在超急性期梗死部位FA值与对照组相应部位比较无明显变化，随后（急性期、亚急性期、慢性期）逐渐降低，2组患者FA值比较差异有统计学意义（P〈0．05）。超急性期、急性期的ADC图表现为低信号，FA图表现为高信号；亚急性期病变区的ADC图为低、等信号；FA图为混杂或低信号；慢性期病变区的ADC图为高信号，FA图为低信号。结论DTI对脑梗死超早期诊断及临床分期有着重要的应用价值。

Diagnostic value of diffusion tensor imaging in different period of cerebral infarction

Objective To explore the evolution law of the magnetic resonance diffusion tensor imaging（DTI） in the dif- ferent periods of the cerebral infarction and its clinical diagnostic value. Methods Fifty-five patients with cerebral infarctions in the different periods were studied as cases group and the 20 healthy volunteers had been chosen as control group for con- trast. The two groups were examined by the DTI. The changes of DTI images ,anisotropic scores（FA） ,apparent diffusion coeffi- cient（ADC） and the FA changing characteristics of the cerebral infarction in the different parts of brain were compared with the corresponding parts of the control group. Results Compared with the corresponding parts of the control group,the FA of the cases group in the different brain parts were different significantly （ P 〈 0.05 ）. Compared with the corresponding parts of the con- trol group,the FA value in the uhra-acute phase of the cases group were not changed obviously and were gradually lower down in acute phase, sub-acute phase and chronic phases, which were different significantly compared with that of control group （P 〈 0. 05 ）. The ADC graph showed low signal and the FA graph showed high signal in the ultra-acute and acute phases ; the ADC graph showed low signal and the FA showed the mixing or low signal in the sub-acute phase;the ADC graph showed high signal and the FA graph showed low signal in the chronic phase. Conclusion DTI has important practical value for the early diagnosis and clinical stages of the cerebral infarction.