DKI與DTI技術(shù)對(duì)輕度腦外傷定量評(píng)估的研究

摘要：目的探討擴(kuò)散峰度成像(DKI)與擴(kuò)散張量成像(DTI)技術(shù)對(duì)輕度顱腦外傷(mTBI)后腦組織微觀結(jié)構(gòu)變化特點(diǎn)的診斷價(jià)值。方法采用DKI及DTI技術(shù)對(duì)40名正常人以及30例mTBI患者(外傷后3天以內(nèi),常規(guī)CT及MRI檢查腦實(shí)質(zhì)內(nèi)均未見(jiàn)明確出血灶)進(jìn)行掃描。對(duì)正常對(duì)照組DTI掃描得到的各向異性(FA)、平均擴(kuò)散系數(shù)(MD)值與DKI掃描得到的FAk、MDk值進(jìn)行相關(guān)性分析。分別于正常對(duì)照組,病例組頭部撞擊側(cè)(傷側(cè))及對(duì)側(cè)鏡像區(qū)尾狀核頭、內(nèi)囊、丘腦、顳葉皮層、胼胝體膝部、胼胝體壓部測(cè)得FA值、MD值、平均峰度(MK)值、峰度各向異性(Ka)值、徑向峰度(Kr)值,正常組和傷側(cè)、正常組和鏡像區(qū)的DTI及DKI掃描得到的值進(jìn)行對(duì)比。結(jié)果正常對(duì)照組各區(qū)域DTI掃描的FA值、MD值分別與DKI掃描的FAk、MDk值相關(guān)(P<0.05)。正常對(duì)照組與mTBI組相比,mTBI組傷側(cè)白質(zhì)區(qū)FA值降低、MD值降低;MK值及Ka值在所有區(qū)域的傷側(cè)升高,在雙側(cè)丘腦、胼胝體膝部及顳葉皮層均升高;Kr值在尾狀核頭、內(nèi)囊、殼核及顳葉皮層的傷側(cè)降低,差異有統(tǒng)計(jì)學(xué)意義(P<0.05)。結(jié)論DTI及DKI技術(shù)均可敏感地檢測(cè)到mTBI患者腦組織損傷后微觀病理改變,而DKI成像能更好地反映更豐富的組織內(nèi)水分子非正態(tài)分布特征,尤其是對(duì)灰質(zhì)的測(cè)量比DTI成像能顯示更多的組織信息及微觀改變,有助于其從病理生理角度解釋mTBI損傷特點(diǎn)。
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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