磁共振彌散張量和波譜成像在缺血性腦小血管疾病中的應(yīng)用研究

張慧麗，李仕紅，張穎冬，周俊山，殷信道

磁共振彌散張量和波譜成像在缺血性腦小血管疾病中的應(yīng)用研究

張慧麗1，李仕紅2，張穎冬3，周俊山3，殷信道4*

目的探討磁共振彌散張量成像(diffusion tensor imaging，DTI)聯(lián)合磁共振波譜成像(magnetic resonance spectroscopy，MRS)對(duì)于缺血性腦小血管疾病(small vessel disease，SVD)的影像評(píng)估價(jià)值。材料與方法對(duì)42例缺血性SVD患者進(jìn)行常規(guī)MRI、DTI和MRS掃描，測(cè)量病灶及健側(cè)對(duì)稱(chēng)正常腦白質(zhì)區(qū)域的平均彌散系數(shù)(average diffusion coefficient，DCavg)值、各向異性分?jǐn)?shù)(fractional anisotropy，F(xiàn)A)值，測(cè)量病灶及其周?chē)ＤX白質(zhì)區(qū)域的N-乙酰天門(mén)冬氨酸(N-acetyl aspartic acid，NAA)、膽堿(choline，Cho)、肌酸(creatine，Cr)、肌醇(myo-inositol，MI)等生化代謝物的濃度值，并計(jì)算NAA/Cho、NAA/Cr、Cho/Cr、MI/Cr的比值。將42例SVD患者的缺血性病灶按照影像學(xué)顯示分組，并對(duì)各組上述測(cè)量指標(biāo)進(jìn)行統(tǒng)計(jì)學(xué)分析。結(jié)果選取42例缺血性SVD患者的42個(gè)病灶并分成慢性缺血組(30例)和慢性期梗死灶組(12例)。SVD病灶的DCavg值和FA值分別較健側(cè)鏡像區(qū)正常腦白質(zhì)的增高和降低(P＜0.01)，而兩組間SVD病灶的DCavg值和FA值差異無(wú)統(tǒng)計(jì)學(xué)意義(P＞0.05)。SVD病灶的NAA、Cho和Cr的均數(shù)都小于周?chē)０踪|(zhì)(P＜0.01)，而兩組間的各項(xiàng)MRS代謝值差異均無(wú)統(tǒng)計(jì)學(xué)意義(P＞0.05)。Pearson相關(guān)性分析，正常腦白質(zhì)的DCavg值與FA值(r=-0.383，P=0.012)呈負(fù)相關(guān)，F(xiàn)A值與NAA/Cho (r=0.420，P=0.006)、NAA/Cr (r=0.382，P=0.012)之間均呈正相關(guān)，而在SVD病灶組無(wú)上述相關(guān)性。Spearman相關(guān)分析，SVD病灶組的DCavg與高血壓呈正相關(guān)(r=0.338，P=0.029)。結(jié)論對(duì)于缺血性SVD，DCavg、FA、NAA、Cho和Cr等檢測(cè)指標(biāo)能夠共同反映神經(jīng)髓鞘結(jié)構(gòu)的微觀變化及其功能的破壞，聯(lián)合應(yīng)用DTI和MRS成像技術(shù)對(duì)缺血性SVD疾病進(jìn)行研究，有助于其臨床診斷及病理機(jī)制的研究。

彌散張量成像；磁共振波譜；腦小血管疾??；磁共振成像

在2013年的中國(guó)腦卒中大會(huì)上，有報(bào)道指出腦血管病已居于中國(guó)居民死亡原因第一位，而由腦小血管疾病(small vessel disease，SVD)引起的腦血管病變約占到1/3[1-2]。SVD是指由直徑小于400μm的腦小血管病變導(dǎo)致的疾病，包括多發(fā)腔隙性腦梗(multiple lacunar infarction，MLI)、皮質(zhì)下動(dòng)脈硬化性腦病(subcortical arteriosclerotic encephalopathy，SAE)、腦白質(zhì)疏松癥(leucoaraiosis，LA)等[3-4]。近年來(lái)國(guó)內(nèi)外多項(xiàng)研究表明[5-9]，SVD與血管性認(rèn)知障礙、血管性癡呆、腦卒中、下肢功能障礙、抑郁癥等疾病有著密切關(guān)系。近年來(lái)，對(duì)于SVD的危險(xiǎn)因素、病理機(jī)制等研究逐漸增多，其中功能磁共振掃描技術(shù)在SVD的研究中得到廣泛應(yīng)用。本研究主要針對(duì)腦SVD中的缺血性病變，運(yùn)用磁共振彌散張量成像(diffusion tensor imaging，DTI)聯(lián)合磁共振波譜成像(magnetic resonance spectroscopy，MRS)對(duì)其臨床診斷及病理變化進(jìn)行研究和探討。

1 材料與方法

1.1 研究對(duì)象

選取至鹽城市第三人民醫(yī)院就診的SVD患者共42例，對(duì)其顱腦進(jìn)行常規(guī)磁共振(magnetic resonance imaging，MRI)、DTI和MRS掃描成像。42例患者中，男20例，女22例，年齡41～78歲，平均64.1歲，高血壓患者26例，糖尿病患者13例。所選研究對(duì)象的準(zhǔn)入標(biāo)準(zhǔn)如下：(1)患者顱腦MRI顯示皮層下白質(zhì)內(nèi)單個(gè)病灶直徑小于15 mm；(2)SVD病灶為非對(duì)稱(chēng)性的患者，即病灶為單側(cè)性或病灶鏡像區(qū)無(wú)病灶；(3)曾有SVD病史，同時(shí)無(wú)大血管病變的病灶，本次就診行MRI常規(guī)檢查時(shí)有腦白質(zhì)疏松者。排除標(biāo)準(zhǔn)：(1)腦外傷、腦占位性病變、腦積水、一氧化碳中毒、低血糖等導(dǎo)致顱腦MRI檢查腦白質(zhì)異常表現(xiàn)者；(2)腦灰質(zhì)腔?；颊?；(3)腔梗合并大面積腦梗死患者。

1.2 MRI數(shù)據(jù)采集

MRI檢查儀采用GE 3.0 T Signa HDx，線(xiàn)圈選用8通道頭頸聯(lián)合線(xiàn)圈。所有患者均行顱腦MRI常規(guī)掃DTI及MRS掃描。

1.2.1 常規(guī)MRI掃描

矢狀位行T1WI (TR/TE=2956/24 ms)，軸位行螺旋槳(Propeller) T2WI (TR/TE=5000/93 ms)、液體衰減反轉(zhuǎn)恢復(fù)(fluid affenuated inversion recovery，F(xiàn)LAIR)序列的T1WI (TR/TE=1875/24 ms)和T2WI (TR/TE=8600/165 ms)、彌散加權(quán)成像(diffusion weighted imaging，DWI；TR/TE=5000/75.9 ms)。

1.2.2 DTI掃描

采用平面回波序列(echo planar imaging，EPI)，在15個(gè)方向上行彌散權(quán)重采集，b=1000 s/mm2，取軸位掃描，28層，層厚5 mm，層距0 mm，F(xiàn)OV 24 cm×24 cm，NEX=1，TR/TE=6600/87.6 ms，掃描時(shí)間為2 min 10 s。

1.2.3 MRS掃描

采用磁共振氫質(zhì)子波譜(1H-MRS)檢查，以軸位T2WI作為MRS掃描定位像，采用PROBE-SI144序列，與掃描控制FWHM≤15，水抑制≥98%，掃描感興趣區(qū)(region of interest， ROI)避開(kāi)顱骨和腦脊液。掃描參數(shù)：TR/TE=1000/144 ms，層厚10 mm，F(xiàn)OV 24 cm×24 cm，NEX=1。

1.3 圖像處理

圖像處理采用GE公司SUN Workstation 4.3 工作站的Functool 5.4.07軟件。

1.3.1 DTI圖像處理

對(duì)DTI原始圖像進(jìn)行校正、調(diào)閾值、降噪、計(jì)算后生成平均彌散系數(shù)(average diffusion coefficient，DCavg)圖和各向異性分?jǐn)?shù)(fractional anisotropy，F(xiàn)A)圖。以T2 FLAIR像為參照，在基底節(jié)區(qū)、側(cè)腦室周?chē)?、半卵圓區(qū)和放射冠區(qū)選擇直徑小于15 mm的病灶，ROI大小范圍在20～55 mm2。同時(shí)獲得同等ROI大小的病灶及對(duì)側(cè)腦白質(zhì)鏡像區(qū)正常腦組織的DCavg和FA值。

1.3.2 MRS圖像處理

Functool軟件自動(dòng)完成MRS原始圖像數(shù)據(jù)的基線(xiàn)校正、曲線(xiàn)校正、代謝物識(shí)別和代謝物波峰下面積的計(jì)算。依照所選病灶的DCavg圖選擇ROI內(nèi)病灶中心和病灶周?chē)ＤX組織的體素，體素選擇時(shí)盡量避免腦脊液周邊可能勻場(chǎng)不均的體素。1H-MRS采集的數(shù)據(jù)包括：(1)以下代謝值：N-乙酰天門(mén)冬氨酸(N-acetyl aspartic acid，NAA)、膽堿(choline，Cho)、肌酸(creatine，Cr)、肌醇(myoinositol，MI)；(2)計(jì)算NAA/Cho、NAA/Cr、Cho/Cr、MI/Cr的比值。

1.4 數(shù)據(jù)統(tǒng)計(jì)分析

數(shù)據(jù)統(tǒng)計(jì)分析采用SPSS 16.0統(tǒng)計(jì)軟件，計(jì)量資料用均數(shù)±標(biāo)準(zhǔn)差表示，兩組間的均數(shù)比較采用獨(dú)立樣本t檢驗(yàn)，配對(duì)設(shè)計(jì)的計(jì)量資料采用配對(duì)t檢驗(yàn)，計(jì)量資料的相關(guān)性分析采用Pearson相關(guān)分析，對(duì)分類(lèi)變量的相關(guān)分析采用Spearman分析。以P＜0.05表示差異有統(tǒng)計(jì)學(xué)意義。

2 結(jié)果

2.1 病灶的MRI影像表現(xiàn)及分組情況

根據(jù)病灶在T1WI Flair、T2WI Flair及DWI成像序列上的不同信號(hào)表現(xiàn)，將42個(gè)病灶分成兩組(見(jiàn)表1、圖1)。

2.2 兩組DTI數(shù)據(jù)分析

取42個(gè)病灶及其對(duì)側(cè)腦鏡像區(qū)同等大小ROI區(qū)域正常腦白質(zhì)的DCavg值和FA值進(jìn)行配對(duì)t檢驗(yàn)，結(jié)果顯示SVD病灶區(qū)域的DCavg值較正常腦白質(zhì)區(qū)域升高(P＜0.01)，而病灶的FA值較正常腦白質(zhì)區(qū)域降低(P＜0.01)，見(jiàn)表2。對(duì)慢性缺血灶組和慢性期梗死組病灶的DCavg值和FA值進(jìn)行獨(dú)立樣本t檢驗(yàn)，結(jié)果顯示兩組間的DCavg值和FA值差異均無(wú)統(tǒng)計(jì)學(xué)意義(P＞0.05)，見(jiàn)表3。

2.3 兩組MRS數(shù)據(jù)分析

將42個(gè)SVD病灶中心與病灶周?chē)０踪|(zhì)區(qū)域內(nèi)MRS各代謝值進(jìn)行比較，病灶的NAA、Cho和Cr的均數(shù)都小于周?chē)０踪|(zhì)(P＜0.01)，而病灶的MI/Cr比值較正常白質(zhì)高(P＜0.05)。兩組間MI值及其他比值差異無(wú)統(tǒng)計(jì)學(xué)意義(P＞0.05)，見(jiàn)表4。對(duì)慢性缺血灶組和慢性期梗死組病灶的各項(xiàng)MRS代謝值進(jìn)行獨(dú)立樣本t檢驗(yàn)，結(jié)果顯示兩組間的各項(xiàng)MRS代謝值差異均無(wú)統(tǒng)計(jì)學(xué)意義(P＞0.05)，見(jiàn)表5。

表1 42個(gè)病灶的MRI表現(xiàn)及分組情況Tab.1 The group of the 42 lesions by MRI displays

表2 SVD病灶與其對(duì)側(cè)腦鏡像區(qū)正常腦白質(zhì)DCavg值和FA值的比較Tab. 2 The comparsion of DCavg value and FA value in the SVD lesion and the normal white matter on the contra-side

表2 SVD病灶與其對(duì)側(cè)腦鏡像區(qū)正常腦白質(zhì)DCavg值和FA值的比較Tab. 2 The comparsion of DCavg value and FA value in the SVD lesion and the normal white matter on the contra-side

注：采用配對(duì)t檢驗(yàn)，**P＜0.01。

組別DCavg (e-10mm2/s)FA病灶組10.186±1.7500.256±0.086對(duì)側(cè)正常腦白質(zhì)組7.963±0.7350.340±0.108t值8.653-5.393P值0.000**0.000**

表3 慢性缺血灶組與慢性期梗死灶組的DCavg值和FA值的比較Tab. 3 The comparison of DCavg value and FA value between chronic ischemic focus group and chronic lacunar infarctions group

表3 慢性缺血灶組與慢性期梗死灶組的DCavg值和FA值的比較Tab. 3 The comparison of DCavg value and FA value between chronic ischemic focus group and chronic lacunar infarctions group

注：采用獨(dú)立樣本t檢驗(yàn)，P＜0.05為差異有統(tǒng)計(jì)學(xué)意義。

組別DCavg (e-10mm2/s)FA慢性缺血灶組9.863±1.0420.268±0.088慢性期梗死組10.992±2.7500.225±0.075t值-1.9521.624P值0.0580.118

圖1 A：T2 Flair 顯示右側(cè)側(cè)腦室前腳前方的低信號(hào)慢性期梗死灶；B：DWI顯示病灶為低信號(hào)；C：DCavg圖示病灶為高信號(hào)，小圓圈為在病灶及對(duì)側(cè)鏡像區(qū)設(shè)置的同等大小的ROI，測(cè)量DCavg值；D：FA顯示病灶區(qū)域低信號(hào)，小圓圈為在病灶及對(duì)側(cè)鏡像區(qū)設(shè)置的同等大小的ROI，測(cè)量FA值Fig. 1 A: T2 Flair shows a chronic lacunar infarction with low signal in the front of right lateral ventricle forefoot; B: DWI shows the infarction with low signal; C: DCavg shows the infarction with high signal, the circles both in the infarction area and the symmetrical side white matter area are the same size ROI that used to measure DCavg value; D: FA shows the infarction with low signal, the circles both in the infarction area and the symmetrical side white matter area are the same size ROI that used to measure FA value.

表4 SVD病灶與病灶周?chē)ＤX白質(zhì)MRS各代謝值的比較Tab.4 The comparison of MRS metabolites in SVD lesions and the normal white around the lesions

表4 SVD病灶與病灶周?chē)ＤX白質(zhì)MRS各代謝值的比較Tab.4 The comparison of MRS metabolites in SVD lesions and the normal white around the lesions

注：采用配對(duì)t檢驗(yàn)，**P＜0.01表示差異有統(tǒng)計(jì)學(xué)意義。

組別NAAChoCrMINAA/ChoNAA/CrCho/CrMI/Cr SVD病灶9227.262±3047.5395520.143±2023.8874907.881±1517.6471078.619±374.7491.741±0.5181.909±0.5081.152±0.2320.235±0.071病灶周?chē)０踪|(zhì)11448.452±3811.0846725.190±2557.4545799.167±1802.0491138.690±385.2231.755±0.5091.983±0.390 1.152±0.2310.204±0.083t值-6.095-4.885-4.990-1.161-0.259-1.4910.0272.342P值0.000**0.000**0.000**0.2520.7970.1440.9790.024*

表5 慢性缺血灶組與慢性期梗死灶組的MRS各代謝值的比較Tab.5 The comparison of MRS metabolites between chronic ischemic focus group and chronic lacunar infarctions group

表5 慢性缺血灶組與慢性期梗死灶組的MRS各代謝值的比較Tab.5 The comparison of MRS metabolites between chronic ischemic focus group and chronic lacunar infarctions group

注：采用獨(dú)立樣本t檢驗(yàn)，P＜0.05為差異有統(tǒng)計(jì)學(xué)意義。

組別NAAChoCrMINAA/ChoNAA/CrCho/CrMI/Cr慢性缺血組9220.567±2941.3175598.233±2074.5394942.000±1626.8841047.333±348.2891.729±0.5141.903±0.4261.143±0.2260.221±0.066慢性期梗死組9244.000±3436.3515324.917±1965.4494822.583±263.3031156.833±440.7951.770±0.5501.923±0.6931.177±0.2560.270±0.073t值-0.022-0.401-0.254-0.770-0.224-0.110-0.407-2.028P值0.9820.6930.8020.4520.8520.9130.6890.057

2.4 兩組DTI分析指標(biāo)、MRS分析指標(biāo)及高血壓、糖尿病間的相關(guān)性分析

將SVD病灶的DCavg值和FA值，及其MRS的NAA、Cho、Cr、MI的代謝值與患者是否患有高血壓或糖尿病進(jìn)行Spearman相關(guān)分析，其中DCavg與高血壓呈正相關(guān)(r=0.338，P=0.029)，而SVD病灶對(duì)側(cè)腦鏡像區(qū)域的腦白質(zhì)的DCavg值和FA值以及SVD病灶周?chē)ＤX白質(zhì)的NAA、Cho、Cr、MI的代謝值與高血壓和糖尿病無(wú)相關(guān)性(P＞0.05)。將SVD病灶的DCavg值、FA值與MRS的各代謝值之間進(jìn)行Pearson相關(guān)性分析，各檢測(cè)指標(biāo)之間無(wú)任何相關(guān)性(P＞0.05)。然而，在正常腦白質(zhì)測(cè)得的DCavg值與FA值(r=-0.383，P=0.012)呈負(fù)相關(guān)，測(cè)得的FA值與NAA/Ch (r=0.420，P=0.006)，以及FA值與NAA/Cr (r=0.382，P=0.012)之間均呈正相關(guān)。

3 討論

SVD是指由腦的小血管及微血管(直徑＜400μm)病變而引起的一組疾病[10]，它們臨床表現(xiàn)相似、影像表現(xiàn)相近[11]。近10多年來(lái)，眾多研究發(fā)現(xiàn)SVD與腦卒中、認(rèn)知障礙、血管性癡呆、慢性腎臟疾病以及抑郁癥等有著密切關(guān)系[7，12]，從而引起了廣泛關(guān)注及學(xué)者們的研究興趣。隨著功能磁共振技術(shù)的發(fā)展，MRI檢查特別是DTI和MRS技術(shù)被越來(lái)越多地運(yùn)用到對(duì)SVD的臨床診斷以及病理機(jī)制的研究中[13-15]。

DTI成像技術(shù)是利用組織中水分子在人體組織中擴(kuò)散運(yùn)動(dòng)存在的各向異性來(lái)探究組織超微結(jié)構(gòu)的成像方法。常用的測(cè)量參數(shù)是平均彌散系數(shù)和部分FA，分別反映的是水分子擴(kuò)散的能力和神經(jīng)髓鞘的完整性、纖維致密性及平行性，即白質(zhì)纖維束的完整程度。FA值越大，神經(jīng)傳導(dǎo)功能便越強(qiáng)。Van Norden等[16-17]認(rèn)為MD值可作為衡量SVD進(jìn)展的重要指標(biāo)，且DCavg值和FA值與認(rèn)知能力有著較強(qiáng)相關(guān)性，特別是FA值可被看作較T2WI更能反映認(rèn)知能力的指標(biāo)。

MRS是一種分子水平的成像，可以無(wú)創(chuàng)性地通過(guò)MRS掃描來(lái)了解人體一定體積的組織中化學(xué)物質(zhì)的含量和濃度。本次研究所采集的檢測(cè)指標(biāo)是腦組織1H-MRS中較為常用的檢測(cè)指標(biāo)。NAA的含量可以反映成熟神經(jīng)元的數(shù)量和功能狀態(tài)，NAA較少意味著神經(jīng)元發(fā)生不可逆轉(zhuǎn)損傷。Cho是髓鞘形成、細(xì)胞代謝和膠質(zhì)增生的指標(biāo)，也是細(xì)胞膜的重要組成成分，反映了細(xì)胞膜磷脂代謝的情況，Cho增高說(shuō)明細(xì)胞膜更新加快，細(xì)胞密度增大。Cr在腦組織中分布均勻且在各病理狀態(tài)下數(shù)值相對(duì)穩(wěn)定，因此常被用作比較其他代謝物濃度變化的參考值。NAA/Cr、Cho/Cr比值常作為反映神經(jīng)元功能的定量指標(biāo)，可判斷神經(jīng)元及髓鞘的完整性和損傷程度。MI則被認(rèn)為是神經(jīng)膠質(zhì)的標(biāo)志物[18]。

本研究中兩組缺血性SVD病灶的DCavg值較健側(cè)正常腦白質(zhì)升高，而FA值則降低，MRS也檢測(cè)到病灶區(qū)代謝物NAA、Cho和Cr較正常腦白質(zhì)減低，這均提示兩組SVD病灶都存在神經(jīng)髓鞘的破壞，白質(zhì)纖維束結(jié)構(gòu)不完整，因此髓鞘對(duì)水分子垂直于神經(jīng)纖維束方向上的運(yùn)動(dòng)限制減小，水分子彌散速度加快，這與相關(guān)文獻(xiàn)報(bào)道一致[13，15]。而慢性缺血組和慢性期梗死灶組病灶的DCavg值和FA值之間差異沒(méi)有統(tǒng)計(jì)學(xué)意義，同樣，兩組的MRS各代謝物數(shù)值及代謝物比值之間差異無(wú)統(tǒng)計(jì)學(xué)意義，原因可能有以下幾個(gè)方面：(1)慢性缺血灶和慢性期梗死灶在病理變化上無(wú)明顯差別或存在交叉病理變化；(2) DCavg值、FA值、NAA值及其他代謝物值只能反映神經(jīng)髓鞘結(jié)構(gòu)遭到破壞，結(jié)構(gòu)不完整，而與結(jié)構(gòu)破壞的程度無(wú)關(guān)[19]；(3)可能與本研究中所選樣本個(gè)體差異及抽樣誤差有關(guān)。

本研究中還發(fā)現(xiàn)缺血性SVD病灶的DCavg值與高血壓因素呈正相關(guān)，而正常腦白質(zhì)的DCavg與高血壓無(wú)相關(guān)性，可能提示高血壓對(duì)缺血性SVD病灶病理變化有影響。其次，正常腦白質(zhì)區(qū)的DCavg值與FA值呈負(fù)相關(guān)，且FA值與NAA/Ch和NAA/Cr呈正相關(guān)，然而SVD病灶的上述指標(biāo)并無(wú)明顯相關(guān)性，提示上述DTI及MRS檢測(cè)指標(biāo)之間的相關(guān)性可以為SVD的診斷提供影像學(xué)依據(jù)，但其準(zhǔn)確性還有待進(jìn)一步研究。

綜上所述，磁共振DTI和MRS兩種功能成像技術(shù)分別從水分子彌散變化及組織代謝兩個(gè)方面反映了腦白質(zhì)神經(jīng)纖維髓鞘結(jié)構(gòu)的病理變化，對(duì)于缺血性SVD在臨床診斷及病理機(jī)制研究等方面較傳統(tǒng)MRI檢查有著明顯的優(yōu)越性。

[References]

[1] Blanco-Rojas L, Arboix A, Canovas D, et al. Cognitive profile in patients with a first-ever lacunar infarct with and without silent lacunes: a comparative study. BMC Neurol, 2013, 13(1): 203.

[2] Fang M, Feng C, Xu Y, et al. Microbleeds and silent brain infarctions are differently associated with cognitive dysfunction in patients with advanced periventricular leukoaraiosis. Int J Med Sci, 2013, 10(10):1307-1313.

[3] Potter GM, Marlborough FJ, Wardlaw JM. Wide variation in definition, detection, and description of lacunar lesions on imaging.Stroke, 2011, 42(2): 359-366.

[4] Zhang HL, Zhang YD, Yin XD, et al. A preliminary study of diffusion tensor iimaging in cerebral small vessel disease. Journal of Nanjing Medical University (Natural Sciences), 2013, 33(11): 1604-1607,1612.張慧麗, 張穎冬, 殷信道, 等.磁共振彌散張量成像在腦小血管病變的應(yīng)用初步研究. 南京醫(yī)科大學(xué)學(xué)報(bào)(自然科學(xué)版), 2013, 33(11):1604-1607,1612.

[5] Lam A, Hamilton-Bruce MA, Jannes J, et al. Cerebral small vessel disease: genetic risk assessment for prevention and treatment. Mol Diagn Ther, 2008, 12(3): 145-156.

[6] Prins ND, van Dijk EJ, den Heijer T, et al. Cerebral small-vessel disease and decline in information processing speed, executive function and memory. Brain, 2005, 128(Pt 9): 2034-2041.

[7] Pantoni L. Cerebral small vessel disease: from pathogenesis and clinical characteristics to therapeutic challenges. Lancet Neurol,2010, 9(7): 689-701.

[8] Verdelho A, Madureira S, Moleiro C, et al. White matter changes and diabetes predict cognitive decline in the elderly: the LADIS study.Neurology, 2010, 75(2): 160-167.

[9] Lin Q, Huang WQ, Teng CM. Genetic associations of leukoaraiosis indicate pathophysiological mechanisms in white matter lesions etiology. Rev Neurosci, 2015, 26(3): 343-358.

[10] Schmidtke K, Hull M. Cerebral small vessel disease: how does it progress?. J Neurol Sci, 2005, 229-230(3): 13-20.

[11] Liu N, Gao PY. Research situation on magnetic resonance imaging of cerebral small vessel disease. Chin J Stroke, 2014, 9(5): 450-454.劉妮, 高培毅. 腦小血管病磁共振影像研究概況. 中國(guó)卒中雜志,2014, 9(5): 450-454.

[12] Zhang AJ, Yu XJ, Wang M. The clinical manifestations and pathophysiology of cerebral small vessel disease. Neurosci Bull,2010, 26(3): 257-264.

[13] Liu J, Zhang LL, Zhang XP, et al. MRS and DTI study of cerebral white matter in small vessel ischemic disease. J Community Med,2014, 12(21): 1-4.劉晉, 張魯臨, 張小鵬, 等. 腦白質(zhì)小血管缺血性病變的MRS、DTI研究. 社區(qū)醫(yī)學(xué)雜志, 2014, 12(21): 1-4.

[14] Wen CY, Wang SY, Wang MH, et al. DTI study of relativity between cerebral small vessel disease and cognitive impairment. J Med Res,2013, 42(2): 174-177.聞彩云, 王溯源, 王美豪, 等. 腦小血管病變與認(rèn)知功能損害相關(guān)性的DTI研究. 醫(yī)學(xué)研究雜志, 2013, 42(2): 174-177.

[15] Yuan Y, Gu JP, Yin XD. Study of cerebral white matter in small vessel ischemic disease with MRS and DTI. Pract Geriatr, 2014,28(11): 941-944.袁勇, 顧建平, 殷信道. 腦白質(zhì)小血管缺血性病變的MRS、DTI研究. 實(shí)用老年醫(yī)學(xué), 2014, 28(11): 941-944.

[16] van Norden AG, de Laat KF, van Dijk EJ, et al. Diffusion tensor imaging and cognition in cerebral small vessel disease: the RUN DMC study. Biochim Biophys Acta, 2012, 1822(3): 401-407.

[17] Charlton RA, Schiavone F, Barrick TR, et al. Diffusion tensor imaging detects age related white matter change over a 2 year followup which is associated with working memory decline. J Neurol Neurosurg Psychiatry, 2010, 81(1): 13-19.

[18] Rango M, Cogiamanian F, Marceglia S, et al. Myoinositol content in the human brain is modified by transcranial direct current stimulation in a matter of minutes: a1H-MRS study. Magn Reson Med, 2008,60(4): 782-789.

[19] Nitkunan A, McIntyre DJ, Barrick TR, et al. Correlations between MRS and DTI in cerebral small vessel disease. NMR Biomed, 2006,19(5): 610-616.

The application research of diffusion tensor imaging and magnetic resonance spectroscopic imaging in ischemic cerebral small vessel disease

ZHANG Hui-li1, LI Shi-hong2, ZHANG Ying-dong3, ZHOU Jun-shan3, YIN Xin-dao4*1School of Radiology, Jiangsu Vocational College of Medicine, Yancheng 224000,China
2Department of Radiology, Yancheng Fumin hospital, Yancheng 224000, China
3Department of Internal Neurology, Nanjing Hospital Affiliated to Nanjing Medical University, Nanjing 210006, China
4Department of Radiology, Nanjing Hospital Affiliated to Nanjing Medical University,Nanjing 210006, China
Co-first Author: LI Shi-hong

Objective:To investigate the medical imaging evaluative value of diffusion tensor imaging combined with magnetic resonance spectroscopy in ischemic cerebral small vessel disease.Materials and Methods:Forty-two cases of ischemic SVD were imaged with conventional MRI, DTI and MRS. Average diffusion coefficient (DCavg) and fractional anisotropy (FA) were measured symmetrically,which in the lesion regions and the contralateral normal white matter area. Then the absolute metabolite concentrations of N-acetylaspartate (NAA), total cholines (Cho),total creatines (Cr) and myo-inositol (MI) in SVD lesion regions and the normal white matter regions around the lesions were detected, and the ratios of NAA/Cho, NAA/Cr, Cho/Cr, MI/Cr were calculated. To divide the 42 lesions of ischemic SVD into groups according to the imaging display, all the indexes above mentioned of each group were statistically analyzed.Results:The 42 lesions of ischemic SVD were divided into chronic ischemic focus group (30 cases) and chronic lacunar infarction group (12 cases). The DCavg values of SVD lesions significantly raised compared with those of the contralateral normal white matter area(P＜0.01), while the FA values of SVD lesions reduced (P＜0.01). Neither DCavg nor FA values between chronic ischemic focus group and chronic lacunar infractions group were significantly different (P＞0.05). The mean values of NAA, Cho and Cr of the SVD lesions were all less than those of the normal white matter regions around the lesions (P＜0.01), but there was no significant difference of MRS metabolic values between chronic ischemic focus group and chronic lacunar infarctions group (P＞0.05).Pearsoncorrelation analysis showed that there was a negative correlation between DCavg value and FA (r=-0.383,P=0.012) in normal white matter, the FA value was positively correlated with NAA/Cho (r=0.420,P=0.006), NAA/Cr (r=0.382,P=0.012),but there was no correlation in the SVD lesions. The DCavg value was actively associated with hypertension in SVD lesions bySpearmancorrelation analysis (r=0.338,P=0.029).Conclusion:For the ischemic SVD, the values of DCavg, FA, NAA, Cho and Cr can reflect the micro variations and the functional damages of nerve neurolemma. Combined application of DTI and MRS could have a great contribution to clinical diagnose and pathological mechanism in ischemic SVD.

Diffusion tensor imaging; Magnetic resonance spectroscopy; Small vessel disease; Magnetic resonance imaging

29 Nov 2016, Accepted 25 Jan 2017

作者單位：
1.江蘇醫(yī)藥職業(yè)學(xué)院醫(yī)學(xué)影像學(xué)院，鹽城 224000
2.鹽城阜民醫(yī)院醫(yī)學(xué)影像科，鹽城224000
3.南京醫(yī)科大學(xué)附屬南京醫(yī)院神經(jīng)內(nèi)科，南京 210006
4.南京醫(yī)科大學(xué)附屬南京醫(yī)院醫(yī)學(xué)影像科，南京 210006

南京市衛(wèi)生青年人才培養(yǎng)工程項(xiàng)目(第一層次)(編號(hào)：QRX11035)；南京市2015年度科技發(fā)展計(jì)劃項(xiàng)目(編號(hào)：201503021)；鹽城市2014年度科技計(jì)劃項(xiàng)目(編號(hào)：YK2014056)

并列第一作者：李仕紅

殷信道，E-mail：y.163yy@163.com

2016-11-29

接受日期：2017-01-25

R445.2；R743.9

A

10.12015/issn.1674-8034.2017.06.004

張慧麗, 李仕紅, 張穎冬, 等. 磁共振彌散張量和波譜成像在缺血性腦小血管疾病中的應(yīng)用研究. 磁共振成像, 2017,8(6): 418-423.

*Correspondence to: Yin XD, E-mail: y.163yy@163.com