【作者】 鲍莎莎；

【导师】 刘青蕊；

【作者基本信息】 河北医科大学 ， 神经病学， 2008， 硕士

【摘要】 目的:急性脑梗死是一种严重危害人类健康的常见病,因此,对其早期确诊、明确病变部位、早期评估预后等有着非常重要的意义。磁共振弥散张量成像（diffusion tensor imaging,DTI）是近年来在常规磁共振成像（magnetic resonance imaging,MRI）和弥散加权成像（diffusion weighted imaging, DWI）基础上发展起来一种建立在水分子布朗运动理论基础上的新的成像技术。弥散张量纤维束成像（diffusion tensor tractography,DTT）是三维显示脑白质纤维束的一种无创性成像方法。这为脑梗死的早期诊断,精确定位及早期评估预后提供了可能。本研究通过分析45例急性脑梗死患者发病后MRI、DWI、DTI图像,研究梗死灶弥散张量参数变化,重建双侧皮质脊髓束（corticospinal tract,CST）并观察病灶与其空间关系,探讨DWI、DTI、DTT在急性脑梗死早期诊断、病变定位及早期评估预后的临床应用价值。方法:选自2006.3²007.12于我科住院的急性脑梗死患者45例,均具有不同程度的神经功能缺损,其中男性34例（75.6%）,女性11例（24.4%）,年龄42-87岁之间,平均年龄62.33±12.57岁,就诊时间为发病后4h⁷d。根据患者病程分为:超早期（<12h）7例,急性期（12²4h）18例,亚急性期（>24h⁷d）20例。入院时行头颅CT排除出血,然后应用Siemens Avanto1.5T磁共振机行头颅常规MRI （矢状位T1WI、T2WI,横轴位T1WI、T2WI）平扫、DWI及DTI检查,测量各期病灶和对侧相应脑组织的部分各向异性（fractional anistrophy,FA）、表观弥散系数（apparent diffusion coefficient,ADC）;病灶的中心及周边各取直径为5mm的区域定义为中心区与边缘区,测定病灶中心区与边缘区FA值、ADC值;运用DTT进行CST三维成像,并将CST受累情况分为3级,1级:CST完整;2级:CST完整,但受压移位;3级:CST中断。在患者入院及治疗后2个月由神经内科医师依据美国国立卫生院脑卒中量表（National Institutes of Health Stroke Scale,NIHSS）对患者做神经功能评分,记录为NIHSS_（1）和NIHSS_（2）。所得资料应用SPSS13.0统计软件进行分析,计数资料采用配对χ²检验,计量资料采用配对t检验,相关分析采用Spearman相关。结果:1 DWI及常规MRI检查结果45例急性脑梗死患者均为右利手。DWI序列均发现责任病灶,阳性率为100%;常规MRI发现责任病灶40例,阳性率为88.89%,5例未被发现病灶的均为超早期患者。DWI阳性率较常规MRI高（χ²=5.00,P<0.05）。2 DTI参数在脑梗死不同病期的变化（1）超早期患者7例,其病灶的FA均值为（0.429±0.052）,对侧相应脑组织FA均值为（0.453±0.056）,两侧比较无统计学意义;病灶的ADC均值为（0.354±0.051）×10^-3mm²/s,对侧相应脑组织ADC均值为（0.408±0.045）×10^-3mm²/s,两侧比较有统计学意义（t=6.599,P<0.01）。（2）急性期患者18例,其病灶的FA均值为（0.452±0.028）,对侧相应脑组织FA均值为（0.500±0.030）,两侧比较有统计学意义（t=10.885,P< 0.01）;病灶的ADC均值为（0.328±0.036）×10^-3mm²/s,对侧相应脑组织ADC均值为（0.377±0.029）×10^-3mm²/s,两侧比较有统计学意义（t=14.386,P<0.01）。（3）亚急性患者20例,其病灶的FA均值为（0.398±0.047）,对侧相应脑组织FA均值为（0.477±0.052）,两侧比较有统计学意义（t=14.537,P< 0.01）;病灶的ADC均值为（0.387±0.016）×10^-3mm²/s,对侧相应脑组织ADC均值为（0.395±0.020）×10^-3mm²/s,两侧比较无统计学意义。3 DTI参数在梗死灶的中心区与边缘区的变化（1）超早期患者病灶的中心区FA均值为（0.426±0.070）,边缘区FA均值（0.434±0.049）,两者比较无统计学意义;中心区ADC均值（0.306±0.074）×10^-3mm²/s,边缘区ADC均值（0.362±0.062）×10^-3mm²/s,两者比较有统计学意义（t=3.057, P<0.05）。（2）急性期患者病灶的中心区FA均值为（0.404±0.039）,边缘区FA均值（0.463±0.030）,两者比较有统计学意义（t=9.954,P<0.01）;中心区ADC均值（0.289±0.036）×10^-3mm²/s,边缘区ADC均值（0.374±0.024）×10^-3mm2 /s,两者比较有统计学意义（t=10.153,P<0.01）。（3）亚急性患者病灶的中心区FA均值为（0.360±0.042）,边缘区FA均值（0.384±0.052）,两者比较无统计学意义;中心区ADC均值（0.379±0.038）×10^-3mm²/s,边缘区ADC均值（0.392±0.020）×10^-3mm²/s,两者比较无统计学意义。4梗死灶FA值与患者临床预后所有患者入院时NIHSS_（1）评分在1¹7之间,平均5.57±2.56;治疗后2个月NIHSS_（2）评分在0¹2之间,平均2.33±2.47。梗死灶FA值降低百分比和NIHSS_（1）相关（r=0.500, P<0.05） ,和NIHSS_（2）评分无相关关系。5皮质脊髓束三维成像45例患者均行双侧皮质脊髓束三维成像,其中表现为1级的22例,2级的13例,3级的10例。皮质脊髓束的损伤程度与NIHSS_（2）相关（r=0.812,P<0.05）。结论:1 DWI、DTI可超早期诊断急性脑梗死,并精确定位。2急性脑梗死患者,梗死灶DTI的参数在不同病期有不同的变化趋势,可协助临床分期。3 DTI对缺血半暗带的判断有一定价值。4梗死灶FA值下降幅度越大,患者的临床症状越严重。它可作为判断预后的客观指标之一。5 DTT图像可判断病灶与皮质脊髓束的关系,分析病灶对皮质脊髓束的影响,可以作为早期评估患者预后的客观依据。更多还原

【Abstract】 Objective: Acute cerebral infarction is a baneful common disease. So coming to diagnosis early and prognosis rationally play an important role in acute cerebral infarction. Magnetic resonance diffusion tensor imaging （DTI） based on conventional magnetic resonance imaging（MRI） and diffusion weighted imaging（DWI） is the water diffusion imaging technique devel- oped in rencent years. Diffusion tensor tractography（DTT）,a new noninvasive technique, can help estimate the structural connectivity of the briar. Analyzing the characteristics of MRI、DWI and DTI in 45 patients with acute cerebral infarction in different phases, measuring the values of fractional anistro- phy（FA）、apparent diffusion coefficient（ADC） in different regions of interests（ROI） and performing bilateral corticospinal tract（CST） to explore the values of DTI in acute cerebral infarction.Methods: Forty-five patients （mean age 62.33±12.57 years, range 42 to 87years old; male 34, female 11） presenting within 7days of the onset were studied. All the patients have neuro- logical impairment in some degree. According to the visiting time, hyper acute phase（<12h）n=7,acute phase（12²4h）n=18, subacute phase（>24h⁷d）n=20. Patients with primary cerebral hemorrhage assessed by computed tomography（CT） were exclu- ded from the study. Conventional MRI （anteroposterior axes T1WI T2WI, abscissa axis T1WI T2WI）、DWI and DTI were performed on a Siemens Avanto 1.5T using a standard. The values of FA and ADC were measured in the infarcted regions, corresponding contralateral regions, and the central and peripheral parts in lesions. CST performed by DTT showed disrupted whose myodnamia was not or not completely recovered. The injured degree of CST in grade 1 was complete, grade 2 was complete but compression shift, grade 3 was break. All the patients were measured according to National Institutes of Health Stroke Scale（NIHSS） when on admission and two months after the onset. The statistics were made by SPSS 13.0, and P<0.05 is considered to have statistical difference. The difference between measurement data was decided by compared t-test, the difference between numeration data was assessed byχ² test, and the correlation analysis was taken by spearman correlation.Results:1 The comparison of the positive result between DWI and MRI（T2WI）All of the 45 patients’are right handedness. All the lesions can be seen on DWI sequence, the positive rate of DWI in infarction detection was 100%. At the same time,only 40 patients were detected through T2WI and the positive rate was 88.89%. The other 5 patients who’s lesions were not undetected were in hyperacute phase. The contrastion showed that the posi- tive rate of DWI was higher than conventional MRI （χ²=5.00, P<0.05）.2 The variation of the FA and ADC in different phases in infarctionADC of lesions were significant in hyperacute and acute phase（P<0.01）. FA of lesions were significant in acute and subacute phase（P<0.01）.3 The variation of the FA and ADC between the central and peripheral parts in lesionsDifference of FA between central and peripheral parts of lesions were significant in acute phase（P<0.01）. Difference of ADC between central and peripheral parts of lesions were significant in hyperacute and acute phase（P<0.05）.4 The relationship between the value of FA and prognosisAll the patients’ NIHSS score was average 5.57±2.56（rage 1 to 17） when on admission and was average 2.33±2.47（rage 0 to 12） two months after the onset. The decreasing percentage of FA value in infarctions has significant positive correlation with NIHSS_（1）（r=0.500,P<0.05）, and has no correlation with NIHS S_（2）.5 The condition of CSTThe CST was created in each patient,and there were 22 cases of grade 1,13 cases of grade 2,10cases of grade 3.Injured degree of CST has significant positive correlation with NIHSS_（2） （r=0.812, P<0.05）. Conclusion:1 DWI、DTI are more sensible than conventional MRI in the diagnosis of hyperacute phase in cerebral infarction.2 There is characteristic discipline in charges of FA and ADC in different phases of stroke and it is useful for staging.3 DTT has important value to detect the ischemic penum- bra.4 The larger the decreasing percentage of FA is, the more serious the clinical manifestation is. It can be considered as an objective index of prognosis.5 Observing the condition of CST in patients with acute cerebral infarction and analyzing the relationship between the impairment of CST and lesions can prognosis early and object- ively.更多还原