王子文 楊本強(qiáng) 劉文源 徐猛 張連雪 徐志華 段陽
膠質(zhì)瘤3D ASL灌注指數(shù)與VEGF MVD表達(dá)相關(guān)性研究
王子文①楊本強(qiáng)②劉文源②徐猛③張連雪①徐志華①段陽②
目的:探究膠質(zhì)瘤磁共振三維動脈自旋標(biāo)記成像(three dimensional arterial spin labeling,3D ASL)腫瘤實(shí)質(zhì)相對血流量(rel?ative cerebral blood flow,rCBF)與血管內(nèi)皮生長因子(vascular endothelial growth factor,VEGF)、微血管密度(micro vessel density,MVD)表達(dá)程度的相關(guān)性。方法:回顧性分析沈陽軍區(qū)總醫(yī)院2014年8月至2016年2月53例經(jīng)術(shù)后病理證實(shí)的膠質(zhì)瘤患者,術(shù)前行MR平掃、增強(qiáng)、3D ASL掃描,術(shù)后行VEGF、MVD表達(dá)程度檢測,分析膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF與VEGF、MVD表達(dá)的關(guān)系。結(jié)果:膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF分別與VEGF、MVD表達(dá)呈正相關(guān)(rs值分別為0.728、0.620,P<0.05)。結(jié)論:膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值與VEGF、MVD表達(dá)呈正相關(guān),說明3D ASL灌注成像技術(shù)有助于評估膠質(zhì)瘤微血管生成情況,對臨床制定適當(dāng)?shù)闹委熡?jì)劃和患者預(yù)后評估有一定意義。
膠質(zhì)瘤三維動脈自旋標(biāo)記血管內(nèi)皮生長因子微血管密度血管生成
膠質(zhì)瘤是顱內(nèi)最常見的原發(fā)惡性腫瘤,其邊緣常與瘤周正常腦組織的分界不清[1],膠質(zhì)瘤對周圍正常腦組織的侵襲主要受膠質(zhì)瘤生物學(xué)行為的影響,其中腫瘤新生微血管的生成是最主要的影響因素之一[2-3]。目前臨床上評價(jià)膠質(zhì)瘤血管生成主要依靠檢測血管內(nèi)皮生長因子(vascular endothelial growth fac?tor,VEGF)或腫瘤微血管密度(microvessel density,MVD)。病理檢測是評價(jià)膠質(zhì)瘤新生血管情況的金標(biāo)準(zhǔn),但需術(shù)后對腫瘤組織進(jìn)行病理檢測,而穿刺活檢又不能準(zhǔn)確評估腫瘤整體惡性程度的情況,因此對VEGF、MVD表達(dá)程度的檢測評估膠質(zhì)瘤血管生成情況缺乏術(shù)前指導(dǎo)意義。而膠質(zhì)瘤磁共振三維動脈自旋標(biāo)記成像(three dimensional arterial spin labeling,3D ASL)可以不使用外源對比劑獲得體內(nèi)的血流灌注情況,對術(shù)前評估膠質(zhì)瘤血管生成情況具有一定臨床意義。
本研究通過膠質(zhì)瘤腫瘤實(shí)質(zhì)相對血流量(rela?tive cerebral blood flow,rCBF)與VEGF、MVD表達(dá)程度的相關(guān)性進(jìn)行比較分析,旨在說明3D ASL灌注成像術(shù)前評估膠質(zhì)瘤微血管生成情況,有利于臨床制定更準(zhǔn)確的治療方案和患者預(yù)后的評價(jià)。
1.1病例資料
回顧性分析沈陽軍區(qū)總醫(yī)院2014年8月至2016年2月期間,經(jīng)術(shù)后病理確診為膠質(zhì)瘤的53例患者。其中男性32例,女性21例,年齡為18~78歲,平均年齡為51.6歲。據(jù)世界衛(wèi)生組織(WHO)中樞神經(jīng)系統(tǒng)腫瘤分類標(biāo)準(zhǔn)(2007年),將患者分為低級別組(Ⅰ、Ⅱ級)28例、高級別組(Ⅲ、Ⅳ級)25例。
2.1膠質(zhì)瘤3D ASL灌注成像特征
53例膠質(zhì)瘤患者均獲得滿意的3D ASL CBF圖,其中低級別膠質(zhì)瘤28例,腫瘤實(shí)質(zhì)rCBF值為1.19± 0.29,呈相對低血流量灌注病灶以藍(lán)黑色成分為主(圖1);高級別膠質(zhì)瘤25例,腫瘤實(shí)質(zhì)rCBF值為3.28±0.89,呈相對較高血流量灌注病灶以紅色成分為主(圖2)。
2.2高、低級別組膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF比較
在53例膠質(zhì)瘤患者中,高級別組膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF高于低級別組,差異具有統(tǒng)計(jì)學(xué)意義(P<0.05,表1)。
表1 高、低級別組膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF的比較Table 1 Comparison of rCBF between the high-and low-grade glioma groups
2.3 高、低級別組膠質(zhì)瘤VEGF、MVD表達(dá)程度的比較
高、低級別組膠質(zhì)瘤之間的VEGF、MVD表達(dá)經(jīng)比較,差異均具有統(tǒng)計(jì)學(xué)意義(P<0.05,表2、3)。
2.4膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值與VEGF、MVD表達(dá)的關(guān)系
腫瘤實(shí)質(zhì)rCBF值與VEGF、MVD的表達(dá)均呈正相關(guān),rs值分別為0.728、0.620,差異均具有統(tǒng)計(jì)學(xué)意義(P<0.05,表4、5)。
表2 高、低級別組膠質(zhì)瘤VEGF表達(dá)的比較Table 2 Comparison of VEGF expression levels between the high-and low-grade
表3 高、低級別組膠質(zhì)瘤MVD表達(dá)的比較Table 3 Comparison of MVD levels between the high-and low-grade glioma groups
表4 膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值與VEGF表達(dá)的關(guān)系Table 4 Correlation between the solid tumor value of rCBF and the VEGF expression levels
表5 膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值與MVD表達(dá)程度的關(guān)系Table 5 Correlation between the solid tumor value of rCBF and the MVD levels
常規(guī)MR掃描圖像和對比增強(qiáng)圖像對評估膠質(zhì)瘤惡性程度具有一定局限性,多項(xiàng)研究[4-6]采用功能性磁共振成像(functional magnetic resonance imaging,fMRI)技術(shù)提高膠質(zhì)瘤惡性程度評價(jià)的精確度,以此來幫助臨床制定治療計(jì)劃和評價(jià)患者預(yù)后。近年來,由于3D ASL灌注成像技術(shù)成熟使其變?yōu)榕R床研究的熱點(diǎn)。3D ASL灌注成像是一種不需要造影劑測定組織循環(huán)灌注的新技術(shù),已有相關(guān)報(bào)道發(fā)現(xiàn)3D ASL灌注成像對于臨床上鑒別診斷膠質(zhì)瘤惡性程度有重要意義[5-6]。Yoo等[7]研究發(fā)現(xiàn)利用3D ASL灌注技術(shù)檢查并測量腫瘤血流量值,結(jié)果顯示3D ASL灌注成像技術(shù)有助于辨別膠質(zhì)瘤的惡性程度。
本研究通過比較高低級別膠質(zhì)瘤3D ASL灌注指數(shù)發(fā)現(xiàn),高級別組膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值顯著高于低級別組,說明3D ASL灌注成像技術(shù)可以對高低級別膠質(zhì)瘤進(jìn)行評估,這與引文一致。Roy等[8]研究比較發(fā)現(xiàn)高級別組膠質(zhì)瘤的灌注高于低級別組,腫瘤的灌注情況與腫瘤實(shí)質(zhì)發(fā)生鈣化、囊變及壞死等有關(guān)。本研究還發(fā)現(xiàn)在MR增強(qiáng)圖像上,高級別膠質(zhì)瘤實(shí)質(zhì)的強(qiáng)化可不顯著,但在CBF圖上呈相對高灌注,這可能是因?yàn)槟[瘤的惡性程度與血管生成有關(guān),惡性程度高的部分并不一定是強(qiáng)化最顯著的區(qū)域。因此,在膠質(zhì)瘤的診斷中,單一觀察MR增強(qiáng)圖像中瘤體的強(qiáng)化程度并不能準(zhǔn)確評價(jià)膠質(zhì)瘤的惡性程度,其只反映腫瘤破壞該區(qū)域血腦屏障的程度[9]。腫瘤微血管生成和血管生成因子的產(chǎn)生是腫瘤生長、浸潤和轉(zhuǎn)移等腫瘤生物學(xué)行為的基礎(chǔ)[10]。血管生成是膠質(zhì)瘤生長、進(jìn)展的必要條件[11]。血管生長因子參與膠質(zhì)瘤血管生成,其中VEGF最為重要,其在膠質(zhì)瘤血管生成過程中起驅(qū)動作用[12-15]。本研究的53例膠質(zhì)瘤患者中,高級別組膠質(zhì)瘤VEGF、MVD均呈陽性表達(dá),其表達(dá)程度高于低級別組,差異具有統(tǒng)計(jì)學(xué)意義(P<0.05)。說明VEGF、MVD的表達(dá)既可以反映腫瘤微血管生成情況,又可以作為評估膠質(zhì)瘤惡性程度的依據(jù)[16-17]。本研究還發(fā)現(xiàn),低級別膠質(zhì)瘤VEGF、MVD呈中度表達(dá)、高級別膠質(zhì)瘤VEGF、MVD呈低度表達(dá)的情況。分析原因可能是部分低級別膠質(zhì)瘤惡性程度具有向高級別膠質(zhì)瘤進(jìn)展的趨勢,膠質(zhì)瘤具有組織結(jié)構(gòu)異質(zhì)性的生物學(xué)特征。然而對VEGF、MVD檢測需要在術(shù)后進(jìn)行,穿刺活檢又不能全面評估整個(gè)腫瘤惡性程度的情況。因此,單純依靠檢測VEGF、MVD表達(dá)程度評估膠質(zhì)瘤惡性程度具有局限性,需要結(jié)合其他相關(guān)診斷技術(shù)進(jìn)一步鑒別。所以,探究膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF與VEGF、MVD表達(dá)程度的相關(guān)性,對進(jìn)一步評估腫瘤新生血管情況,辨別膠質(zhì)瘤惡性程度,進(jìn)而幫助臨床制定適當(dāng)?shù)闹委熡?jì)劃和患者預(yù)后的評估是很有必要的。Viel等[18]研究顯示膠質(zhì)瘤的血管生成是評價(jià)膠質(zhì)瘤增殖的關(guān)鍵,膠質(zhì)瘤的生長、侵襲及生物學(xué)行為都依靠血管進(jìn)行。
本研究中53例膠質(zhì)瘤患者的腫瘤實(shí)質(zhì)rCBF值與VEGF、MVD表達(dá)呈顯著正相關(guān),隨著VEGF、MVD表達(dá)程度增加,膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF值也明顯增大,說明腫瘤的生長依賴于新生血管的形成,腫瘤細(xì)胞產(chǎn)生促使VEGF的能力增強(qiáng),腫瘤的新生血管越多,腫瘤生長越迅速,腫瘤細(xì)胞的惡性程度越高??梢娔z質(zhì)瘤腫瘤實(shí)質(zhì)rCBF的高低和VEGF、MVD表達(dá)程度的高低及腫瘤新生微血管活性的高低具有明顯的一致性。
3D ASL灌注成像是一種無創(chuàng)獲得體內(nèi)血流灌注情況的技術(shù),能夠客觀分析瘤體血液動力學(xué)改變,間接反映出腫瘤的生物學(xué)行為,在膠質(zhì)瘤惡性程度的評估中具有一定的臨床應(yīng)用價(jià)值。但目前研究狀態(tài)和進(jìn)展尚需與其他臨床技術(shù)相結(jié)合,并有待于大樣本對照研究。
綜上所述,膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF與VEGF、MVD表達(dá)程度呈顯著正相關(guān),說明3D ASL灌注成像可通過腫瘤血流量的測量預(yù)測腫瘤微血管生成來評估膠質(zhì)瘤的惡性程度,其臨床意義在于提高對腫瘤微血管生成的認(rèn)識,繼而可以幫助臨床醫(yī)生進(jìn)一步對腫瘤微血管生成、腫瘤侵潤等腫瘤生物學(xué)特征的研究,對選擇適當(dāng)?shù)闹委煼桨讣盎颊哳A(yù)后的評估提供幫助。
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2016-03-13收稿)
(2016-06-12修回)
Correlation of 3D ASL perfusion index with the expression of VEGF and MVD in glioma
Ziwen WANG1,Benqiang YANG2,Wenyuan LIU2,Meng XU3,Lianxue ZHANG1,Zhihua XU1,Yang DUAN2
Correspondence to:Yang DUAN;E-mail:duanyang100@126.com
1Jinzhou Medical University,General Hospital of Shenyang Military Region of PLA Training Base for Graduate,Shenyang 110016,China;2Department of Radiology,General Hospital of Shenyang Military Region of PLA,Shenyang 110016,China;3Department of Imaging,Hospital of Panshi,Panshi 132300,China
Objective:To investigate the correlation of the relative cerebral blood flow(rCBF)of three dimensional arterial spin labeling (3D ASL)with vascular endothelial growth factor(VEGF)expression and microvessel density(MVD)in glioma.Methods:Fifty-three glioma patients confirmed by pathology were subjected to conventional,enhanced MR and 3D ASL imaging before operation to determine VEGF expression and MVD levels in each patient.The correlations of rCBF with VEGF expression and MVD in glioma were evaluated,respectively.Results:rCBF was noted to be positively correlated to VEGF expression and MVD in glioma.The rs were 0.728(VEGF)and 0.620(MVD),respectively(P<0.05).Conclusion:The positive correlation of rCBF with VEGF expression and MVD in glioma implied that 3D ASL is beneficial for evaluating microvessel angiogenesis in glioma prior to surgery.This finding is significant for developing clinical treatment plans and for assessing patient prognoses.
glioma,3D arterial spin labeling,vascular endothelial growth factor,microvessel density,angiogenesis
10.3969/j.issn.1000-8179.2016.13.292
①錦州醫(yī)科大學(xué),中國人民解放軍沈陽軍區(qū)總醫(yī)院研究生培養(yǎng)基地(沈陽市110016);②沈陽軍區(qū)總醫(yī)院放射診斷科;③磐石市醫(yī)院影像科
段陽duanyang100@126.com
1.2方法
1.2.1檢查方法采用GE Discovery MR750 3.0T磁共振掃描儀,頭部8通道專用線圈(美國GE公司)。對53例患者行T1WI、T2WI、T2 FLAIR、3D ASL及靜脈注射釓貝葡胺(Gd-DTPA,0.2 mmoL/kg體質(zhì)量)對比增強(qiáng)掃描(注射流率3.0 mL/s)(圖1、2)。常規(guī)MRI掃描參數(shù):T1WI軸位、矢狀位掃描(TR=1 900 ms,TE=19 ms),T2WI軸位掃描(TR=6 000 ms,TE=96 ms),T2WI FLAIR軸位掃描(TR=8 800 ms,TE=94 ms,TI=2 500 ms),T1WI軸位、矢狀位、冠狀位對比增強(qiáng)掃描(TR=1 860 ms,TE=19 ms),掃描層數(shù)21,層厚5 mm,層間距1 mm,視野(FOV)240 mm×240 mm,激勵(lì)次數(shù)(NEX)1,矩陣256×256。
3D ASL成像掃描為TR=4 674 ms,TE=10.5 ms,視野(FOV)240 mm×240 mm,激勵(lì)次數(shù)(NEX)3,層厚5 mm,標(biāo)記后延遲時(shí)間(post label delay time)1 525 ms,根據(jù)常規(guī)T2WI上病變的范圍采用多層采集的方式,共采集21幅灌注原始圖像。
1.2.2圖像分析方法應(yīng)用GE ADW 4.6后處理工作站Functool軟件進(jìn)行圖像后處理,獲得3D ASL腦血流量(cerebral blood flow,CBF)圖,觀測每位患者的CBF圖,并結(jié)合常規(guī)序列掃描圖像,測量層面為腫瘤實(shí)質(zhì)在軸位的最大層面,選定感興趣區(qū)域(region of interest,ROI)。腫瘤實(shí)質(zhì)ROI定位避開腫瘤的壞死或瘤內(nèi)出血區(qū)域。鏡像區(qū)腦組織ROI定位應(yīng)避開顱骨、動靜脈、腦池等解剖部位,ROI面積為30~40 mm2,在膠質(zhì)瘤瘤體取灌注最高的區(qū)域測量最大腫瘤血流量(the maximal tumor blood flow,TBFmax),在對側(cè)腦組織測量鏡像區(qū)CBF。因個(gè)體性差異,不同患者的CBF會產(chǎn)生差別,為消除個(gè)體性差異,本研究采用TBFmax相對標(biāo)準(zhǔn)化,經(jīng)標(biāo)準(zhǔn)化獲取腫瘤實(shí)質(zhì)rCBF。標(biāo)準(zhǔn)化公式為:rCBF=TBFmax/CBF。
1.2.3免疫組織化學(xué)染色方法選取患者存檔的石蠟標(biāo)本,連續(xù)切片5張,層厚2 μm,采用免疫組織化學(xué)鏈霉菌抗生物素蛋白-過氧化物酶法(streptavi?din-peroxidase method,SP法)對切片行免疫組織化學(xué)染色。VEGF、MVD陽性表達(dá)均為棕黃色。任意確定3個(gè)高倍可視范圍(×200倍),在每個(gè)可視范圍內(nèi)統(tǒng)計(jì)陽性細(xì)胞的數(shù)目。計(jì)算陽性百分率取平均值,陽性表達(dá)的百分率=陽性表達(dá)細(xì)胞數(shù)/視野區(qū)總細(xì)胞數(shù)。分別將VEGF、MVD表達(dá)程度分為4組:陰性及低中高組分別為0、<25%、25%~50%、>50%(圖3、4)。
圖154歲女性患者左側(cè)顳葉膠質(zhì)瘤(WHOⅠ級)
Figure 154-year-old female with glioma in the left temporal lobe (WHO gradeⅠ)
圖244歲女性患者右側(cè)額葉膠質(zhì)瘤 (WHOⅢ級)
Figure 244-year-old female with glioma in the right frontal lobe(WHO gradeⅢ)
1.3統(tǒng)計(jì)學(xué)方法
采用SPSS 17.0軟件進(jìn)行統(tǒng)計(jì)學(xué)分析。數(shù)據(jù)以x±s表示,對高低級別組膠質(zhì)瘤腫瘤實(shí)質(zhì)rCBF比較采用t檢驗(yàn);對高低級別組之間的VEGF、MVD表達(dá)程度的比較采用秩和檢驗(yàn);分析腫瘤實(shí)質(zhì)rCBF與VEGF、MVD表達(dá)程度的關(guān)系采用Spearman相關(guān)系數(shù)分析法。統(tǒng)計(jì)結(jié)果均以P<0.05為差異具有統(tǒng)計(jì)學(xué)意義。
圖3膠質(zhì)瘤VEGF表達(dá) (SP×200)
Figure 3VEGF expression levels in glioma(SP×200)
A.Low VEGF expression;B.Moderate VEGF expression;C.High VEGF expression
圖4膠質(zhì)瘤MVD表達(dá) (SP×200)
Figure 4MVD expression levels in glioma(SP×200)
A.Low MVD expression;B.Moderate MVD expression;C.High MVD expression
王子文專業(yè)方向?yàn)橹袠猩窠?jīng)系統(tǒng)腫瘤影像學(xué)診斷。E-mail:wangziwen101@126.com