磁共振弥散张量成像在脑梗死中的应用

摘要

目的 应用磁共振弥散张量成像(DTI)技术分析缺血性脑梗死不同时期的表观弥散系数(ADC)、各向异性分数(FA)变化,并通过弥散张量纤维束成像(DTT)观察梗死灶与皮质脊髓束(CST)位置关系,以评估预后.方法 45例由于皮质脊髓束受损所致运动功能障碍的不同时期脑梗死患者作为研究组,分为超急性期(＜6h)、急性期(6h～3d)、亚急性期(4d～8w)和慢性期(＞8w),分析其DTI参数的变化特点,并与正常组进行比较.结果 患侧FA值在超急性期无明显变化,在急性期、亚急性期及慢性期逐渐降低,与健侧和对照组比较有显著性差异(P值均<0.05);患侧ADC值在超急性期、急性期明显减低,亚急性期逐渐恢复接近于健侧,慢性期再度增高;DTT成像显示CST受损严重其预后较差.结论 不同时期脑梗死病灶其FA、ADC值有一定规律变化,DTT图像可无创性的显示梗死灶与皮质脊髓束的空间位置关系,可作为评估预后的客观依据.%Objective The indexes of FA and ADC in diffusion tensor imaging ( DTI ) were studied and the relationship between infarcted focus and cortical spinal tract ( CST ) was analyzed in the patients with cerebral infarction in order to evaluate clinical prognosis. Methods Forty-five patients who suffered from motor dysfunction were divided into hyperacute phase ( < 6h ), acute phase ( 6h ～ 3d ), subacute phase ( 4d ～ 8w ) and chronic phase ( > 8w ) group. The values of FA and ADC in the infarction and corresponding region were measured and compared to the control group. The values of FA in infarction regions were significantly lower than the corresponding regions in acute,subacute and chronic phases ( P<0.05 ) that didn't change obviously in hyperacute phases; the value of ADC in infarction regions were significantly lower than that of the corresponding in hyperacute and acute phases ( P<0. 05 ), almost the same level in subacute and increased in chronic phase; the more serious CST damaged in DTT, the poorer prognosis in patients. Conclusion The variations of FA and ADC in different phases of cerebral infarction have invariably regularities; DTT can show the relationship between infarcted and CST clearly and as an objective proof for evaluating prognosis.