磁共振弥散张量成像联合神经纤维束示踪技术在诊断脑梗死中的应用

目的近年来,磁共振弥散张量成像(diffusion tensor imaging,DTI)在评估脑白质神经纤维方面得到广泛应用。文中分析脑梗死患者磁共振DTI的参数变化,探讨其在脑梗死诊断中的应用价值。方法 36例脑梗死患者根据病程分为超急性期7例(<6h),急性期21例(6～72h)、亚急性期8例(72h～14d)。应用GE1.5T磁共振成像仪行头颅常规磁共振成像(mag-netic resonance imaging,MRI)及DTI检查,测量各期病灶中心区部分各向异性(fractional anisotropy,FA),并与梗死对侧进行对比。运用弥散张量纤维束成像(diffusion tensor tractography,DTT)显示通过病灶的纤维束特征。结果超急性期中心区与对侧FA值分别为(0.454±0.073)vs(0.479±0.050),P>0.05;急性期病灶中心区与对侧FA值分别为(0.353±0.070)vs(0.490±0.039),P<0.01;亚急性期病灶中心区与对侧FA值分别为(0.301±0.061)vs(0.475±0.041),P<0.01。随着病情进展,梗死灶FA值逐渐下降。36例患者中,皮质脊髓束完整(1级)者3例,病灶致使皮质脊髓束受压、移位(2级)者12例,皮质脊髓束中断(3级)者21例,皮质脊髓束的损伤程度与肌力下降程度相关(rs=0.893,P<0.01)。结论 FA测量及皮质脊髓束成像联合应用能更精确地对脑梗死进行分期和定位,在判断患者预后及指导患者康复治疗等方面具有重要作用。

Diffusion tensor imaging combined with fractional anisotropy measurement for the diagnosis of cerebral infarction

Objective In recent years,diffusion tensor imaging(DTI) has been widely applied as a non-invasive method to the evaluation of the structure of brain white matter fibers.This study aimed to analyze the characteristics of magnetic resonance DTI and explore the values of DTI in the diagnosis of cerebral infarction.Methods Thirty-six patients with acute cerebral infarction were classified into three groups according to the disease course: hyperacute(<6 h,n=7),acute(6-72 h,n=21),and subacute(>3-14 d,n=8).Conventional MRI and DTI were performed using GE 1.5T to measure the values of fractional anisotropy(FA) in the infarcted region and corresponding contralateral area.Visualization of the fibertract was achieved by postprocessing the acquired DTI data.Results The FA values of the infarcted region and corresponding contralateral area were 0.454±0.073 and 0.479±0.050 in the hyperacute stage(P>0.05),0.353±0.070 and 0.490±0.039 in the acute stage(P<0.01),and 0.301±0.061 and 0.475±0.041(P<0.01) in the subacute stage.FA decreased gradually with the progression of the disease.Among the 36 patients,there were 3 cases of complete corticospinal tract(CST),12 cases of compressed and shifted CST,and 21 cases of broken CST.The severity of CST involvement was positively correlated with the degree of muscle weakness(rs=0.893,P<0.01).Conclusion DTI combined with FA measurement can precisely stage and localize cerebral infarction,and plays an important role in evaluating the prognosis of the disease and guiding the rehabilitation of the patient.