DTI技术在早期脑梗死患者治疗前后与肌力功能相关性研究的应用

Application of DTI technology in detecting correlation between early cerebral infarction and muscle strength function

目的评价MRI扩散张量成像(DTI)在脑梗死后早期皮质脊髓束(CST)Wallerian变性(WD)与肌力功能相关性研究中应用价值。方法选择60例单侧大脑CST分布区早期脑梗死伴肌力功能障碍患者,其中男性41例,女性19例;年龄40~76岁,平均年龄65岁;体质量36~80 kg,平均体质量63 kg;病程1~7 d,平均病程5 d。采用GE 1.5 T超导型MRI,在起病后第7天行MRI DTI检查,测量两侧CST下行区平均扩散率(DCavg)、容积比率(1-VR)及分数各向异性系数(FA)。以患侧为观察组、健侧镜面区为对照组,比较两侧DCavg、1-VR及FA值差异。按起病初期患侧肌力受损程度分轻度组、中度组及重度组,按治疗后患侧肌力恢复程度分明显恢复组、部分恢复组及无明显恢复组,比较各组患侧CST的DCavg、1-VR及FA值差异。结果健侧FA值0.800±0.030,1-VR值0.743±0.053,DCavg值7.601±0.630;患侧FA值0.632±0.149,1-VR值0.522±0.164,DCavg值7.407±0.800;肌力受损轻度组、中度组、重度组FA值分别为0.757±0.043、0.647±0.059、0.415±0.100,1-VR值分别为0.663±0.060、0.517±0.095、0.312±0.119,DCavg值分别为7.428±0.627、7.411±0.993、7.367±0.774;肌力明显恢复组、部分恢复组及无明显恢复组FA值分别为0.742±0.053、0.653±0.083、0.425±0.110,1-VR值分别为0.649±0.071、0.526±0.106、0.313±0.121,DCavg值分别为7.579±0.643、7.342±0.934、7.221±0.824。患侧与健侧DCavg值及各组患侧DCavg值差异均无统计学意义(P> 0.05)。患侧与健侧1-VR及FA值差异有显著统计学意义(P <0.01)。患侧肌力受损轻度组、中度组及重度组1-VR、FA值差异有显著统计学意义(P <0.01),且1-VR及FA值与早期肌力受损严重程度呈负相关。治疗后肌力明显恢复组、部分恢复组及无明显恢复组1-VR、FA值差异有显著统计学意义(P <0.01),且1-VR及FA值与肌力恢复程度呈正相关。结论脑梗死后早期CST变性的1-VR、FA值变化与患侧肌力受损程度及所能恢复程度存在相关性,早期DTI可为患者治疗后肌力所能恢复程度的预判提供较为直接有效的量化性指标依据。

Objective To evaluate application value of diffusion tensor imaging(DTI)in detecting correlation between early corticospinal tract(CST)Wallerian degeneration(WD)and muscle strength after cerebral infarction.Methods A total of 60 patients of early cerebral infarction associated with myodynamic dysfunction in distribution area of unilateral cerebral CST were enrolled,which included 41 males and 19 females,aged 40-76 years old with mean age of 65 years old;body weight was 36-80 kg with mean body weight of 63 kg;duration of disease was 1-7 days with mean duration of 5-day.The GE 1.5 T superconducting MRI was used to observe the average diffusivity(DCavg),1-volume ratio(1-VR)and fractional anisotropy coefficient(FA)at 2 sides of CST on duration of day 7.The affected side as observation group and contralateral mirror area as control group.DCavg,1-VR and FA value between 2 groups were compared.According to the degree of impaired muscle strength at the initial stage of onset,patients divided into mild group,moderate group and severe group.Based on recovery degree of ipsilateral muscle strength after treatment,patients were divided into recovery group,partial recovery group and non-obvious recovery group.The differences of DCavg,1-VR and FA value of CST in each group were compared.Results In control group,FA value was 0.800±0.030,1-VR value was 0.743±0.053 and DCavg value was 7.601±0.630.In observation group,FA value was 0.632±0.149,1-VR value was 0.522±0.164,and DCavg value was 7.407±0.800.The FA value of mild group,moderate group and severe group was 0.757±0.043,0.647±0.059 and 0.415±0.100,respectively;1-VR value was 0.663±0.060,0.517±0.095 and 0.312±0.119,respectively;DCavg value was 7.428±0.627,7.411±0.993 and 7.367±0.774,respectively.The FA value of recovery group,partial recovery group and non-obvious recovery group were 0.742±0.053,0.653±0.083,0.425±0.110,and 1-VR value were 0.649±0.071,0.526±0.106,0.313±0.121,respectively.The DCavg value was7.579±0.643,7.342±0.934 and 7.221±0.824,respectively.There was no significant difference in DCavg value between observation group and control group(P>0.05),and there was no significant difference in each group(P>0.05).There was significant difference in 1-VR and FA between observation group and control group(P<0.01).There was significant difference in1-VR and FA in mild group,moderate and severe group(P<0.01),and value of 1-VR and FA was negatively correlated with the severity of early muscle damage.After treatment,there was significant difference in value of 1-VR and FA in recovery group,partial recovery group and non-obvious recovery group(P<0.01),and value of 1-VR and FA was positively correlated with degree of muscle strength recovery.Conclusion It is demonstrated that the changes of 1-VR and FA in early CST degeneration after cerebral infarction are correlated with degree of muscle strength and recovery,early DTI could provide direct and effective quantitative basis for predicting the recovery of muscle strength after treatment.