DKI与DTI技术对轻度脑外伤定量评估的研究

DKI与DTI技术对轻度脑外伤定量评估的研究

摘要：目的探讨扩散峰度成像(DKI)与扩散张量成像(DTI)技术对轻度颅脑外伤(mTBI)后脑组织微观结构变化特点的诊断价值。方法采用DKI及DTI技术对40名正常人以及30例mTBI患者(外伤后3天以内,常规CT及MRI检查脑实质内均未见明确出血灶)进行扫描。对正常对照组DTI扫描得到的各向异性(FA)、平均扩散系数(MD)值与DKI扫描得到的FAk、MDk值进行相关性分析。分别于正常对照组,病例组头部撞击侧(伤侧)及对侧镜像区尾状核头、内囊、丘脑、颞叶皮层、胼胝体膝部、胼胝体压部测得FA值、MD值、平均峰度(MK)值、峰度各向异性(Ka)值、径向峰度(Kr)值,正常组和伤侧、正常组和镜像区的DTI及DKI扫描得到的值进行对比。结果正常对照组各区域DTI扫描的FA值、MD值分别与DKI扫描的FAk、MDk值相关(P<0.05)。正常对照组与mTBI组相比,mTBI组伤侧白质区FA值降低、MD值降低;MK值及Ka值在所有区域的伤侧升高,在双侧丘脑、胼胝体膝部及颞叶皮层均升高;Kr值在尾状核头、内囊、壳核及颞叶皮层的伤侧降低,差异有统计学意义(P<0.05)。结论DTI及DKI技术均可敏感地检测到mTBI患者脑组织损伤后微观病理改变,而DKI成像能更好地反映更丰富的组织内水分子非正态分布特征,尤其是对灰质的测量比DTI成像能显示更多的组织信息及微观改变,有助于其从病理生理角度解释mTBI损伤特点。
Objective To explore the clinical value of MR diffusion tensor imaging( DTI) and diffusion kurtosis imaging( DKI) in diagnosing tiny changes of brain tissue after mild traumatic brain injury( mTBI). Methods A total of 30patients with mTBI( study group) and 40 healthy subjects( control group) were enrolled in this study. No definite bleeding site was demonstrated on routine CT or MRI in all 30 patients( 3 days after injury). DTI and DKI MR scanning was employed in all 30 patients and 40 healthy subjects. FA as well as MD values obtained from DTI,and FAk as well as MDk obtained from DKI were determined. The correlation analysis was conducted. FA,MD,MK,Ka and Kr of both DTI parameters and DKI parameters in the caput nucleus caudate,internal capsule,thalamus,cortex of temporal lobe,genu of corpus callosum,splenium corporis callosi at the injured side and the mirror regions were measured,and the results were compared between the two groups. Results In the control group,the FA and MD values obtained from DTI were well correlated with FAk and MDk values obtained from DKI( P < 0. 05). Compared with the control group,in the study group both FA and MD values of cerebral white matter at the injured side were significantly reduced,while MK and Ka values were increased in all traumatic areas,including bilateral thalamus,genu of corpus callosum and cortex of temporal lobe. Kr values in the caput nucleus caudate,internal capsule,thalamus and cortex of temporal lobe at the injured side were decreased,and the differences were statistically significant( P < 0. 05). Conclusion Both DTI and DKI techniques can sensitively detect the tiny pathologic changes of cerebral tissue in mTBI patients. Moreover,DKI imaging can more correctly reflect the characteristics of non-orthostate distribution of free water molecules within the cerebral tissue,which is very helpful in making explanation of mTBI features.


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