摘要:目的 探讨磁共振扩散张量成像(DTI)各参数动态评估急性颈髓损伤脊髓功能预后的临床应用价值.方法 2012年10月至2015年12月在滨州医学院烟台附属医院23例急性颈髓损伤首诊常规磁共振成像(MRI)T2WI高信号行DTI检查,临床按照美国脊髓损伤协会(ASIA)残损标准,治疗1个月后根据脊髓功能转归分为无改善组(A组)4例(2例ASIA-A级、2例B级)和改善组(B组)19例(13例ASIA-C级、5例D级、l例B级),15名健康志愿者作为健康对照组(C组).应用配对t检验分别对A组、B组治疗前后DTI各参数中部分各向异性(FA)值、平均表观扩散系数(ADC)值和轴向本征值[λ∥=λ1]、径向本征值[λ⊥=(λ2+λ3)/2]进行比较,采用单因素方差(ANOVA)分析治疗后A组、B组与C组间DTI各参数值差异,两两比较采用LSD检验.治疗前后DTI测量区域一致.扩散张量纤维束示踪技术(DTr)显示A组和B组治疗前后神经纤维束改变.结果 A组治疗前、后FA值分别为0.47±0.07、0.41±0.05,ADC值为(0.92 ±0.15)、(1.09±0.11)×l0-3mm2/s,λ∥值1.46±0.36、1.49±0.22,λ⊥值0.66±0.11、0.82 ±0.09,治疗后FA值低于治疗前、ADC值和λ⊥值均高于治疗前,差异均有统计学意义(t=3.037、-4.183、-4.805,均P<0.05),λ∥值差异无统计学意义(t=-1.160,P>0.05).B组治疗前后FA值分别为0.58±0.06、0.65±0.10,ADC值为(1.08±0.12)、(1.26±0.11) ×10-3 mm2/s,λ∥值为1.78 ±0.22、1.80±0.22,λ⊥值为0.68±0.14、0.56±0.11,治疗后FA值、ADC值均高于治疗前、λ⊥值低于治疗前,差异均有统计学意义(t=-3.344、-3.642、4.694,均P<0.05),λ∥值差异无统计学意义(t=-0.596,P>0.05).治疗前后A组和B组FA值与λ⊥值变化完全相反,A组λ∥值低于B组,ADC值均高于治疗前.C组FA值0.73±0.05,ADC值(0.95±0.08)×10-3 mm2/s,λ#值1.82±0.07,λ⊥值0.44±0.07,组间比较,FA值、λ∥值、λ⊥值、ADC值差异均有统计学意义(F=71.958、70.432、75.902、22.521,均P<0.01).两两比较,FA值低、λ⊥值高差异均有统计学意义(均P<0.05),λ∥值A组低于C组差异有统计学意义(P<0.05)、B组和C组差异无统计学意义(P>0.05),ADC值A组和C组差异无统计学意义(P>0,05),B组和C组差异有统计学意义(P<0.05).DTT显示A组治疗后神经纤维束稀疏、断续,B组神经纤维束完整.结论 FA值、λ⊥值动态变化是评估急性颈髓损伤脊髓功能预后最敏感的指标,λ∥值次之.FA值持续低、λ⊥值持续高、λ∥值低提示脊髓功能预后差.DTT可以直观显示神经纤维束细微改变.%Objective To evaluate the clinical application value of diffusion tensor imaging (DTI) parameter in evaluating the prognosis of spinal cord injury in acute cervical spinal cord injury.Method From October 2012 to December 2015,a total of 23 patients with acute cervical spinal cord injury were examined by routine MRI-T2WI high signal DTI examination,according to the American Spinal Injury Association (ASIA) damage standard.One month later according to the functional outcome of the spinal cord,all patients were divided into non improvement group (group A) 4 cases (2 cases of ASIA-A,2 cases of grade B) and improvement group (group B) 19 cases (13 cases of ASIA-C,5 cases of grade D,1 case of grade B),15 cases of healthy volunteers as the normal group (group C).The FA value,ADC and axial eigen value [λ// =λ1],radial eigen value [λ ⊥ =(λ2 + λ3)/2] of before and after the treatment in group A and group B were compared by paired t test respectively.Single factor analysis of variance (ANOVA) was used to analyze the differences of DTI among the group A,group B and group C,and LSD test was used to compare the differences among the groups.Before and after treatment,the DTI measurement area was consistent.Changes of nerve fiber bundles in group A and group B before and after treatment were displayed in DTT.Results After the treatment,the FA value of group A decreased,ADC value and λ ⊥ value increased than that of before treatment (t =3.037,-4.183,-4.805,all P < 0.05),λ//value increased (t =-1.160,P >0.05).After the treatment,the FA value and ADC value of group B increased,λ⊥ value decreased than that of before treatment (t =-3.344,-3.642,4.694,all P < 0.05),λ// value increased (t =-0.596,P > 0.05).After treatment,there were statistical differences in FA values,λ ⊥ value,ADC values and λ//values among three groups (F =71.958,70.432,75.902,22.521,all P < 0.01).Conclusion The changes of FA value,λ⊥ value are the two most sensitive indicators of acute cervical spinal cord injury of spinal cord function prognosis.It suggests the poor prognosis of spinal cord function when FA value decreases and λ ⊥ value continues to increase.DTT can visually display subtle changes in the nerve fiber bundle.