斑點(diǎn)追蹤成像結(jié)合實時心肌超聲造影對心肌不同灌注狀態(tài)的評價

蔣媛媛,徐　洋,任衛(wèi)東

(1.廈門大學(xué)附屬第一醫(yī)院超聲科,福建廈門361001;2.廈門大學(xué)附屬第一醫(yī)院整形外科,福建廈門361001;3.中國醫(yī)科大學(xué)附屬盛京醫(yī)院超聲科,沈陽110004)

斑點(diǎn)追蹤成像結(jié)合實時心肌超聲造影對心肌不同灌注狀態(tài)的評價

蔣媛媛1,徐洋2,任衛(wèi)東3

(1.廈門大學(xué)附屬第一醫(yī)院超聲科,福建廈門361001;2.廈門大學(xué)附屬第一醫(yī)院整形外科,福建廈門361001;3.中國醫(yī)科大學(xué)附屬盛京醫(yī)院超聲科,沈陽110004)

目的定量評價急性心肌梗死(AMI)經(jīng)皮冠狀動脈介入治療(PCI)術(shù)前、術(shù)后左心室局部心肌功能和心肌灌注的動態(tài)變化.方法選取48例接受PCI手術(shù)治療的1周內(nèi)AMI患者(治療組)和30例健康志愿者(對照組),采用斑點(diǎn)追蹤成像(STI)及實時心肌超聲造影(RT-MCE)技術(shù)評價PCI手術(shù)前后局部縱向應(yīng)變及心肌灌注變化特征,并與單光子發(fā)射計算機(jī)斷層掃描術(shù)(SPECT)結(jié)果進(jìn)行相關(guān)性分析.結(jié)果PCI術(shù)前,治療組各應(yīng)變和灌注指標(biāo)均較對照組明顯降低.PCI術(shù)后1個月,與術(shù)前比較,除部分心肌節(jié)段心肌造影劑灌注速率無改善外,其他各指標(biāo)均明顯升高,差異有統(tǒng)計學(xué)意義(P<0.05);術(shù)后1個月,左心室局部縱向峰值應(yīng)變、心肌灌注達(dá)峰強(qiáng)度和局部心肌血流量與單光子發(fā)射計算機(jī)斷層成像術(shù)的心肌灌注量呈正相關(guān)(r分別為0.75、0.72、0.76,均P<0.05).結(jié)論STI技術(shù)結(jié)合RT-MCE技術(shù)能夠準(zhǔn)確評價AMI患者PCI手術(shù)前后的左心室局部功能和心肌灌注的變化特征.

斑點(diǎn)追蹤成像;實時心肌超聲造影;心肌梗死

網(wǎng)絡(luò)出版地址

左心室局部收縮功能與多種因素有關(guān),最為密切的是冠狀動脈狹窄程度,臨床上經(jīng)皮冠狀動脈介入治療(percutaneous trans1umina1 coronary intervention,PCI)能使痙攣或阻塞的血管再通,使受損心肌部分或全部恢復(fù)功能,最終提高左心室整體收縮功能[1],正確評價PCI術(shù)前、術(shù)后左心室收縮功能對于臨床評估療效和給予指導(dǎo)意見具有重要意義[2].本研究聯(lián)合斑點(diǎn)追蹤顯像(speck1e tracking imaging,STI)技術(shù)及實時心肌造影(rea1-time myocardia1 contrast echocardiography,RT-MCE)技術(shù)對擇期PCI患者術(shù)前、術(shù)后的心肌運(yùn)動和心肌灌注進(jìn)行評價,并以單光子發(fā)射計算機(jī)斷層掃描術(shù)(sing1e-photon emission computed tomography,SPECT)作為"金標(biāo)準(zhǔn)"進(jìn)行相關(guān)性分析,旨在進(jìn)一步明確PCI術(shù)后較長時間心肌的變化.

1　材料與方法

1.1一般資料

選取2010年2月至2012年2月中國醫(yī)科大學(xué)附屬盛京醫(yī)院超聲科急性心肌梗死(acute myocardia1 infarction,AMI)患者48例(治療組),男35例,女13例,年齡52～77歲,平均(67±19)歲.其中合并高血壓11例,合并糖尿病7例.同時,對48例中的30例患者行術(shù)后SPECT,以此"金標(biāo)準(zhǔn)"來判斷心肌活動恢復(fù)情況.選取同期在我院門診或住院部篩選的健康志愿者30例(對照組),男、女各15例,年齡50～74歲,平均(62±15)歲.經(jīng)仔細(xì)病史詢問、心電圖等檢查明確無器質(zhì)性心臟疾病.以上采集均經(jīng)被研究者本人同意.

1.2儀器與方法

采用GE Vivid7 Dimension彩色多普勒超聲診斷儀,該儀器配備Echo PAC工作站,具有STI及RTMCE分析程序,同時配備M4s心臟探頭,頻率1.5/ 3.1 MHz,幀頻80幀/s.M3s心臟探頭,頻率1.7/3.4 MHz,閃爍幀頻23幀/s,閃爍幀數(shù)20幀,機(jī)械指數(shù)(mechanica1 index,MI)0.08.囑受檢者采取左側(cè)臥位,平靜呼吸,同步記錄胸導(dǎo)聯(lián)心電圖,在采集圖像時盡量保持心率的一致性.常規(guī)超聲檢查后記錄并儲存左心室兩腔、三腔和四腔長軸切面,二維圖像各3個心動周期以備脫機(jī)分析.

1.3統(tǒng)計學(xué)分析

2　結(jié)果

2.1對照組、治療組左心室應(yīng)變和心肌造影結(jié)果比較

對照組左心室節(jié)段縱向應(yīng)變曲線的形態(tài)為負(fù)向單峰曲線,心肌收縮時,應(yīng)變從0向負(fù)值發(fā)展,于收縮末達(dá)到最大負(fù)值;舒張時心肌延長,應(yīng)變從最大負(fù)值向0基線靠近.應(yīng)變值心尖部>基底部,室間隔基底部最低.RT-MCE顯示:經(jīng)靜脈注入造影劑后,左心室各壁心肌灌注良好,心肌灌注曲線中,造影劑灌注達(dá)峰強(qiáng)度(perfusion peak intension,PI)、造影劑峰值聲學(xué)強(qiáng)度(acoustic intensity peak,A)、造影劑灌注速率即微氣泡平均速度(contrast agent perfusion rate,K)和局部心肌血流量(regiona1 myocardia1 b1ood f1ow,MBF)各項指標(biāo)均呈現(xiàn)心尖部灌注略比基底部和大部分中間部高,但差異無統(tǒng)計學(xué)意義(P> 0.05).見表1.

治療組應(yīng)變曲線顯示:心肌梗死室壁節(jié)段縱向收縮期峰值應(yīng)變(the 1ongitudina1 systo1ic peak strain,SLP)值均有減低,曲線形態(tài)紊亂,規(guī)律性消失,T-SLP時間曲線峰值后移;靜脈注入造影劑后,可見缺血心肌節(jié)段灌注緩慢,部分節(jié)段明顯充盈缺損.灌注曲線顯示:灌注強(qiáng)度明顯減低,微泡速度減慢,局部心肌血流量減少,與對照組比較差異均有統(tǒng)計學(xué)意義(P<0.01).見表1,圖1.

2.2PCI術(shù)后各指標(biāo)比較

PCI術(shù)后1個月,應(yīng)變峰值繼續(xù)增高,形態(tài)略規(guī)整,灌注與術(shù)前比較,造影劑充盈略增快,除部分心肌節(jié)段K值改善不明顯外,其余各指標(biāo)升高均有統(tǒng)計學(xué)差異(P<0.05),但仍明顯低于對照組,見表1,圖1、2.

2.4治療組應(yīng)變指標(biāo)與灌注指標(biāo)同SPECT心肌灌注量的相關(guān)性分析

術(shù)后1個月,左心室SLP、PI和MBF與SPECT心肌灌注量呈正相關(guān)(r分別為0.75、0.72、0.76,均P< 0.05);T-SLP、A和K亦與SPECT心肌灌注量呈正相關(guān)(r分別為0.68、0.61、0.70,均P<0.05),但相關(guān)性不如SLP、PI和MBF.

2.5放射性分布結(jié)果

靜息狀態(tài)下,放射性分布減弱或明顯減弱的心肌節(jié)段,在行硝酸甘油介入顯像后,部分心肌節(jié)段有稀疏放射性分布或原放射性分布區(qū)域增強(qiáng),可定義為存活心肌,見圖3.

3　討論

STI技術(shù)所評價的左心室整體收縮功能與心臟磁共振成像的結(jié)果大體一致,具有良好的準(zhǔn)確性和重復(fù)性[3],此技術(shù)不受心室壁運(yùn)動時產(chǎn)生的角度影響,能更客觀地評價左心室局部心肌功能[4,5].所以,STI技術(shù)具有評估心肌局部和整體收縮功能的特點(diǎn)[6,7].

表1　治療組與對照組左心室各指標(biāo)比較(±s)Tab.1 Com parison of the general index between the therapy group and normal group(±s)

表1　治療組與對照組左心室各指標(biāo)比較(±s)Tab.1 Com parison of the general index between the therapy group and normal group(±s)

1)compared with contro1 group,P<0.05;2)compared with preoperation group,P<0.05.SLP,the 1ongitudina1 systo1ic peak strain;T-SLP,the 1ongitudina1 peak strain of time;PI,contrast agent perfusion of peak intensity;A,acoustic intensity peak;K,contrast agent perfusion rate;MBF,regiona1 myocardia1 b1ood f1ow.

Item Contro1 group Treatment group Preoperation One month after operation SLP(%) Bas 22.83±3.27 7.01±1.991)16.98±3.042)Mid 24.56±3.44 7.71±1.931)19.38±2.752)Apex 26.15±2.59 7.66±1.821)17.24±2.442)T-SLP(ms) Bas 116.56±4.21 152.56±4.531)126.94±3.811),2)Mid 111.66±4.11 146.31±3.471)122.34±3.011),2)Apex 106.11±3.65 151.68±3.721)125.54±3.661),2)PI(au) Bas 36.21±0.81 9.91±1.111)30.26±0.972)Mid 36.37±0.85 11.35±0.991)31.36±0.992)Apex 39.27±0.70 11.22±1.011)28.36±0.771),2)A(dB) Bas 20.88±0.52 11.01±1.081)17.26±0.872)Mid 22.86±0.59 11.31±0.911)17.69±0.732)Apex 24.45±0.61 9.28±1.041)16.14±0.901),2)K Bas 2.51±0.22 1.63±0.361)2.23±0.652)Mid 2.55±0.25 1.61±0.351)2.61±0.991),2)Apex 2.55±0.25 1.35±2.111)2.12±1.122)MBF(dB) Bas 52.74±0.49 17.86±0.91)38.36±0.651),2)Mid 58.39±0.47 18.32±0.871)34.01±0.541),2)Apex 63.57±0.42 14.97±0.911)34.33±0.701),2)

圖1　治療組1例患者AM I左心室縱向應(yīng)變曲線Fig.1 Segmental left ventricular longitudina l strain curve of a AMI patient

RT-MCE技術(shù)所使用的微氣泡通過肺循環(huán)到左心系統(tǒng)最終進(jìn)入心肌組織,高機(jī)械指數(shù)可擊破心肌內(nèi)微泡,再轉(zhuǎn)為低機(jī)械指數(shù)觀察心肌血流再灌注的過程,多數(shù)學(xué)者認(rèn)為實時心肌造影能真實準(zhǔn)確地反映心肌灌注情況[8～10].

在本研究中,左心室術(shù)前梗死節(jié)段應(yīng)變值均較對照組明顯減低.無論對于ST段抬高患者還是非ST段抬高患者,在超聲圖像上均表現(xiàn)為縱向應(yīng)變運(yùn)動減弱,達(dá)峰時間延長.文獻(xiàn)[11,12]表明兩者的病死率無明顯差異.梗死區(qū)心肌MCE曲線灌注強(qiáng)度峰值明顯降低,灌注速度減慢,心肌血流量減少,與STI所得的心肌運(yùn)動減慢結(jié)果一致.本研究結(jié)果顯示,雖然術(shù)后1個月各項指標(biāo)均較術(shù)前明顯恢復(fù),但與正常人比較仍具有一定的差距,所有患者雖行再灌注治療,但為擇期手術(shù),其效果遠(yuǎn)不如急診PCI術(shù)顯著,再次證實了心肌細(xì)胞的壞死是不可逆的.當(dāng)然,由于隨訪時間有限,不能完全排除部分心肌仍處于冬眠狀態(tài)的可能.

圖2　治療組1例患者AM I左心室心肌灌注曲線Fig.2 Segmental left ventricular myocardial perfusion curve of a AMI patient

圖3　SPECT放射性分布比較Fig.3 SPECT radioactive distribution

結(jié)果顯示,PCI術(shù)后1個月各指標(biāo)改善明顯(P< 0.05),可能與缺血區(qū)微循環(huán)血管的改變有關(guān).本研究中術(shù)后1個月MCE曲線顯示代表局部微血管血流狀態(tài)的PI、A、K和MBF值均增高,PI和MBF增高較明顯,這與微循環(huán)的動態(tài)變化一致,側(cè)枝循環(huán)的開放和頓抑心肌的激活可使局部微血管密度增加,雖然血管的擴(kuò)張及側(cè)枝循環(huán)血流遠(yuǎn)遠(yuǎn)不如正常供血量,但仍可增加一定范圍內(nèi)的MBF和PI,PI與微血管密度、毛細(xì)血管密度、毛細(xì)血管面積相關(guān),但與小動脈密度和膠原含量成反比[13].由于微血管床的壓力仍然很高,當(dāng)微泡進(jìn)入微血管時,A和K始終保持低水平增高.以上心肌灌注曲線變化同STI的縱向應(yīng)變測量值一致,說明這種較長時間微循環(huán)灌注的改善能夠推測心肌形變特點(diǎn),而局部心肌運(yùn)動狀態(tài)也同樣能預(yù)測微循環(huán)灌注水平.

本研究中各灌注指標(biāo)隨時間延長逐漸增加,證明缺血區(qū)具有一定量的微血管儲備,心肌功能逐漸恢復(fù),可認(rèn)為是存活心肌.反映心肌組織形變的STI技術(shù)較少受到心臟整體運(yùn)動以及鄰近節(jié)段剪切力的影響[14],心肌梗死節(jié)段SLP、T-SLP隨時間延長改善明顯,可以認(rèn)為有存活心肌存在.缺血區(qū)仍具有部分微血管完整性,本研究中各灌注指標(biāo)隨時間延長逐漸增加,證明缺血區(qū)具有一定量的微血管儲備,心肌功能逐漸恢復(fù),可以認(rèn)為是存活心肌. SPECT用來評價心肌的灌注和細(xì)胞膜完整性,被稱為檢測存活心肌的"金標(biāo)準(zhǔn)".本研究48例PCI患者在術(shù)后1個月進(jìn)行了核素心肌灌注斷層顯像檢查,結(jié)果顯示運(yùn)動和灌注良好的心肌攝取基本正常,運(yùn)動不良和灌注缺損的心肌攝取明顯減弱或局部放射性分布嚴(yán)重減弱,與STI技術(shù)和MCE結(jié)果一致.

綜上所述,應(yīng)用STI技術(shù)結(jié)合RT-MCE技術(shù)可以定量評價AMI后存活心肌,能夠較好反映PCI術(shù)后短期和長期療效,兩者結(jié)合評價AMI后存活心肌與SPECT心肌灌注量呈正相關(guān),其中SLP、PI和MBF相關(guān)性良好.2種技術(shù)的結(jié)合能夠準(zhǔn)確評價心肌缺血再灌注后的心肌運(yùn)動狀態(tài),為臨床評估心臟功能提供了一種有效的方法.但本研究存在一定的局限性,未排除其他疾病,可能會對研究結(jié)果造成一定偏倚;僅隨訪至術(shù)后1個月,對于術(shù)后更長期的變化有待于進(jìn)一步研究;研究樣本量較小,對于研究結(jié)果可能存在一定的偏差.因此,在以后的工作中將結(jié)合三維超聲,并進(jìn)行組織活檢,同時延長隨訪時間,對不同狀態(tài)下的心肌灌注進(jìn)行更深入的研究.

[1]Chen M,Wang J,Xie MX,et a1.Rea1-time three-dimensiona1 echocardiographic assessment of 1eft ventricu1ar remode1ing index in patients with hypertensive heart disease and coronary artery disease [J].J Huazhong Univ Sci Techno1og Med Sci,2009,29(1): 122-126.

[2]Miyoshi T,Doi M,Hirohata S,et a1.Cardio-ank1e vascu1ar index is independent1y associated with the severity of coronary atherosc1erosis and 1eft ventricu1ar function in patients with ischemic heart disease[J].J A therosc1er Thromb,2010,17(3):249-258.

[3]Laurent M,O1ivier L,Ju1ien N,et a1.Impact of acoustic window on accuracy of 1ongitudina1 g1oba1 strain:a comparison study to cardiac magnetic resonance[J].Eur J Echocardiogr,2011,12(5):394-399.

[4]Tsai WC,Liu YW,Huang YY,et a1.Diagnostic va1ue of segmenta1 1ongitudina1 strain by automated function imaging in coronary artery disease without 1eft ventricu1ar dysfunction[J].J Am Society Echocardiogr,2010,23(11):1183-1189.

[5]陳劉平,鄧又斌,劉紅云,等.斑點(diǎn)追蹤超聲心動圖技術(shù)評價肺切除患者早期左心室局部及整體心肌收縮功能[J].中國介入影像與治療學(xué),2010,7(3):292-295.

[6]陳明,謝明星,王新房.實時三維超聲心動圖測量左心功能評價冠狀動脈搭橋術(shù)的效果[J].中國介入影像與治療學(xué),2010,7 (3):281-284.

[7]范潔,田家瑋,杜國慶,等.超聲二維應(yīng)變技術(shù)對不同術(shù)式二尖瓣置換前后左心室收縮功能的研究[J].中華超聲影像學(xué)雜志, 2012,21(1):1-5.

[8]Abde1moneim SS,Dhob1e A,Bernier M,et a1.Quantitative myocardia1 contrast echocardiography during pharmaco1ogica1 stress for diagnosis of coronary artery disease:a systematic review and meta-ana1ysis of diagnosis accuracy studies[J].Eur J Echocardiogr,2009,10 (7):813-825.

[9]Che1iah RK,Hickman M,Kinsey C,et a1.Myocardia1 contrast echocardiography versus sing1e photon emission computed tomography for assessment of hibernating myocardium in ischemic cardiomyopathy:pre1iminary qua1itative and quantitative resu1ts[J].J Am Soc Echocardiogr,2010,23(8):840-847.

[10]Li DY,Liang L,Xu TD,et a1.The va1ue of quantitative rea1-time myocardia1 contrast echocardiography for detection of angiographica11y significant coronary artery disease[J].C1in Cardio1,2013,36 (8):468-474.

[11]Young A1tahan R,Go1denberg I,Kim ron L,et a1.Timing of coronary angiography and outcome in patients with non-ST e1evation acute coronary syndromes Israe1i survey[J].Cardio1ogy,2011,119 (4):224-234.

[12]Navarese EP,De Servi S,Gibson CM,et a1.Ear1y vs.de1ayed invasive strategy in patients with acute coronary syndromes without ST-segment e1evation:a meta-ana1ysis of randomized studies[J].QJM, 2011,104(3):193-200.

[13]Shimoni S,Frangogiannis NG,Agge1i CJ,et a1.Microvascu1ar structura1 corre 1ates of myocardia1 contrast echocardiography in patients with coronary artery disease and 1eft ventricu1ar dysfunction imp1ications for the assessment of myocardia1 hibernation[J].Circu1ation,2002,106(8):950-956.

[14]Urheim S,Edvardsen T,Torp H,et a1.Myocardia1 strain by dopp1er echocardio-graphy:va1idation of a new method to quantify regiona1 myocardia1 function[J].Circu1ation,2000,102(10):1158-1164.

(編輯武玉欣)

Evaluation of DifferentPerfusion StatusofM yocardium Using Speckle Tracking Imagingand Real-timeM yocardialContrastEchocardiography

JIANGYuan-yuan1,XUYang2,RENWei-dong3
(1.DepartmentofU1trasound,TheFirstAffi1iated Hospita1ofMedicine,XiamenUniversity,Xiamen361001,China;2.DepartmentofP1asticSurgery,TheFirstAffi1iated Hospita1ofMedicine,XiamenUniversity,Xiamen 361001,China;2.Department ofU1trasound,ShengjingHospita1,ChinaMedica1University,Shenyang110004, China)

Objective To quantitative1y eva1uate the 1eft ventricu1ar regiona1 myocardia1 function and myocardia1 perfusion in patients with acute myocardia1infarction(AMI)beforeand afterpercutaneouscoronary intervention(PCI)usingspeck1e trackingimaging(STI)and rea1-timemyocardia1 contrast echocardiography(RT-MCE).Methods LV 1ength-axis images were acquired in 48 patients with AMI who underwent successfu1 PCI within 1-month of AMI onset(treatment group),as we11 as 30 hea1thy individua1s as contro1 group.Conventiona1 echocardiography,STI and RTMCEweredone in both 2groupsbeforeand 1month after PCI.Thecorre1ation ana1ysisbetween theaboveindexand sing1e-photon emission computed tomography(SPECT)after PCI 1 month was a1so studied.Results Before PCI,a severe reduction in strain and perfusion was observed in treatment group compared to the contro1 group.One month after PCI,there were obvious changes in strain and perfusion index in treatment group,except partia1 myocardia1 region in K.Even.A1though there were marked1y improvement of the most index,significant differences were found between the twogroups(P<0.05).Onemonth postoperation,1oca11ongitudina1peak strainof1eftventricu1ar,myocardia1perfusionofpeak intensityand regiona1 myocardia1 b1ood f1ow were positive1y corre1ated with sing1e photon emission computed tomography amount of myocardia1 perfusion imaging (SPECT)(r were 0.75,0.72,0.76,P<0.05).Conclusion STI combined with RT-MCE can accurate1y eva1uate the regiona1 myocardia1 motion and perfusion ofAMIpatientsbeforeand after PCIand canmonitor theimprovementofmyocardia1function after revascu1arization.

speck1e tracking imaging;rea1-time myocardia1 contrast echocar diography;myocardia1 infarction

R540.45;R542.22

A

0258-4646(2016)03-0264-05

10.12007/j.issn.0258-4646.2016.03.018

蔣媛媛(1980-),女,醫(yī)師,博士.

任衛(wèi)東,E-mai1:renwd01@163.com

2015-07-27

網(wǎng)絡(luò)出版時間: