磁共振弥散张量成像对脑小血管病变的诊断效能研究

Study on the diagnostic efficacy of MR DTI in cerebral SVD

目的:研究磁共振弥散张量成像(DTI)对脑小血管病变(SVD)的诊断效能。方法:选取医院救治的86例SVD患者,依据成像序列上的不同信号表现将其分为急性期梗死组(12例)、慢性期梗死组(30例)及慢性缺血灶组(56例)3组,所有患者均进行磁共振常规序列及DTI序列检查,测量患者病灶、健灶、双侧内囊后肢及上册大脑脚的平均弥散系数(DCavg)和纤维束各向异性系数(FA)值,利用DTT技术获得患者皮质脊髓束(CST)成像,分析SVD病灶中的CST图像,比较患肢及键肢的DCavg及FA值;分析DCavg及FA值的相关性。结果:在86例患者中发现SVD病灶98个,其中SVD病灶患区的DCavg值明显高于健侧,FA值明显低于健侧,差异有统计学意义(t=3.392,t=25.490;P<0.05);大脑脚患区的DCavg值明显高于健侧,内囊后肢患侧的FA值明显低于健侧,差异有统计学意义(t=4.323,t=11.320;P<0.05);大脑脚两侧FA值及内囊后肢两侧的DCavg值差异无统计学意义。3组患灶DCavg值差异无统计学意义;FA值在3组患灶差异有统计学意义(F=796.360,P<0.05)。DCavg与FA呈明显负相关(r=-0.561,P<0.01)。结论:SVD患者病灶的DCavg值出现一定程度升高,FA值一定程度下降,DTT图像可反应SVD对皮质脊髓束的影响情况,DTI在诊断SVD中具有重要的临床参考价值。

Objective:To study the diagnostic efficacy of magnetic resonance(MR)diffusion tensor imaging(DTI)on cerebral small vessel disease(SVD).Methods:86 patients with SVD who admitted to hospital were selected and were divided into three groups,which included acute phase infarction group(12 cases),chronic phase infarction group(30 cases)and chronic ischemic focus group(56 cases),according to different signal manifestations on imaging sequences.All patients underwent the examinations of conventional MRI sequence and DTI sequence.The values of average diffusion coefficients(DCavg)and fractional anisotropy(FA)of fiber bundle on lesion,healthy focus,bilateral posterior limbs of internal capsule and upper cerebral peduncle of them were further measured.And DTT technique was applied to obtain the imaging results of corticospinal tract(CST),and the CST images in SVD lesions were further analyzed.And the values of DCavg and FA between the limbs with lesion and the health limbs were compared,and then the correlation between DCavg and FA was further analyzed.Results:98 SVD lesions were found in 86 patients,and the DCavg value of the affected area of SVD lesion was significantly higher than that of the healthy side,and the FA value of the affected area of SVD lesion was significantly lower than that of the healthy side(t=3.392,t=25.490,P<0.05).The DCavg value of the cerebral peduncle area was significantly higher than that of healthy side,and the FA value of the affected side of posterior limb of internal capsule was significantly lower than that of healthy side(t=4.323,t=11.320,P<0.05).There were no significant difference in FA value between the two sides of cerebral peduncle and in DCavg value between posterior limb of internal capsule.The difference of DCavg values of lesions among three groups was no significant,and the difference of FA value of lesions among three groups was significant(F=796.360,P<0.05).Pearson correlation analysis showed that DCavg was negatively correlated with FA(r=-0.561,P<0.01).Conclusion:The DCavg value of the lesions in SVD patients appears increase to a certain extent,while the FA value appears decrease to a certain extent.DTT images can reflect the influence of SVD on corticospinal tract.DTI has important clinical reference value in diagnosing SVD.