基于DTI技术的急性中风患者缺血脑白质纤维束的扩散性与神经功能恢复的相关性研究

目的：通过扩散张量成像(diffusion tensor imaging，DTI)评价急性缺血性中风患者脑白质纤维束的扩散性与神经功能恢复的相关性，预测患者运动功能的恢复情况。材料与方法40例临床诊断并经磁共振扫描证实有单侧急性脑白质梗塞并有运动功能障碍患者行DTI检查后，于治疗后1个月、2个月及3个月末行常规MRI和DTI检查，获得部分各向异性指数(FA)和表观扩散系数(ADC)。分别于缺血白质区域和对侧同名纤维束镜像区域取感兴趣区，测量FA值、A D C值后计算比值(rFA和rADC)以及梗塞体积，观察其与美国国立卫生研究院脑中风评分(NIHSS)的相关性。其中32名1年后随访到的患者，根据其运动力指数(MI)，分成恢复良好组和恢复不良组，运用rFA和rADC判断运动功能的恢复情况。结果 rFA、rADC和梗塞体积于首诊、治疗1个月末、2个月末和3个月末之间均存在统计学差异(F=13.84，P=0.00，F=64.57，P=0.00和F=37.41，P=0.00)。首诊和1个月末rFA与NIHSS评分显著负相关(r=－0.59，t=－4.59，P=0.00和r=－0.34，t=－2.27，P=0.02)；首诊rADC与NIHSS评分显著负相关(r=－0.44，t=－3.04，P=0.00)，1个月末、2个月末、3个月末rADC与NIHSS评分显著正相关(r=0.28，t=1.83，P=0.04；r=0.39，t=2.69，P=0.00；r=0.63，t=4.99，P=0.00)。1月个末、2个月末、3个月末梗塞体积与NIHSS评分显著正相关(r=0.40， t=2.73，P=0.01；r=0.44，t=3.05，P=0.00；r=0.32，t=2.13，P=0.04)。多元回归分析显示首诊rFA和3个月末rADC与患者1年后的MI有显著相关性(t=2.95， P=0.00和t=2.75，P=0.01)，3个月末rADC的ROC曲线峰下面积为0.905。结论 DTI技术能显示急性脑缺血患者脑白质纤维束损伤治疗后的演变，其测定参数与神经功能恢复有一定相关性，3个月末ADC值或可用于预测患者运动功能恢复情况。

A correlation study between diffusivity of ischemic white matter ifber tract and neuro-functional recovery in patients with acute stroke by using DTI technique

Objective:To evaluate the correlation between diffusivity of ischemic white matter ifber tract and neuro-functional recovery in acute stroke patients by using DTI, and try to predict the motor outcome of these patients. Materials and Methods:Forty unilateral cerebral ischemic patients with motor dysfunction underwent MRI and DTI study within three days after the onset of illness. MRI and DTI scans were done one, two and three month after treatment. Fractional anisotropy (FA) and apparent diffusion coefifcient (ADC) maps were obtained. With the reference of DW images,regions of interest (ROIs) were selected on the ischemic white matter ifber tract, and the control ROIs were selected on the contra-lateral homonymic white matter ifber tract. The ratios of FA and ADC (rFA and rADC) within these ROIs and infarction volume were calculated. The relationship between DTI parameters with infarction volume and national institute of health stroke scale (NIHSS) scores were assessed. According to motricity index (MI), a total of thirty-two stroke follow-up patients after one year treatment were divided into no motor deifcit group and motor deifcit group and DTI parameters were used to predict the motor outcome.Results:Signiifcant differences were found regarding rFA, rADC and infarction volume of ischemic white matter ifber tract among the onset, one, two and three months of the stroke patients (F=13.84,P=0.00;F=64.57,P=0.00 andF=37.41,P=0.00). There was signiifcantly negative correlation between rFA and NIHSS scores at the onset and one month (r=-0.59,t=-4.59,P=0.00;r=-0.34,t=-2.27,P=0.02) and between rADC and NIHSS scores at the onset (r=-0.44,t=-3.04,P=0.00). There was signiifcantly positive correlation between rADC and NIHSS (r=0.28,t=1.83,P=0.04;r=0.39,t=2.69,P=0.00;r=0.63,t=4.99,P=0.00) and between the infarction volume and NIHSS scores (r=0.40,t=2.73,P=0.01;r=0.44,t=3.05,P=0.00;r= 0.32,t=2.13,P=0.04) at one, two and three months from the onset. There was signiifcant correlation between the rFA of the onset, the rADC of three months treatment and MI of thirty-two stroke patients after one year (t=2.95,P=0.00 andt=2.75,P=0.01). For rADC at three months, the area under curves of ROC was 0.905.Conclusion:Our results suggest that there could be a signiifcant correlation between the change of diffusivity of the ischemic white matter and the neuro-functional recovery in the acute stroke patients by analyzing DTI metrics. ADC values at three months after onset of the acute stroke patients may be used to predict the motor outcome.