本文選題：超聲 + 微泡�。� 參考：《第三軍醫(yī)大學(xué)》2017年博士論文

【摘要】：研究背景:血栓形成及栓塞是大量心腦血管疾病的病理基礎(chǔ)。目前,經(jīng)靜脈給予tPA等藥物溶栓是這類疾病主流的治療方法。經(jīng)靜脈溶栓有嚴(yán)格的時間窗,安全性和有效性也還有較大的提高空間。經(jīng)導(dǎo)管介入治療是當(dāng)前臨床血栓性疾病的另一類治療方法。最近幾年,隨著更有效的新型介入取栓導(dǎo)管的使用,研究表明,機(jī)械取栓聯(lián)合全身或局部注射溶栓藥可以提高梗阻血管的早期再通率、改善預(yù)后,因此,經(jīng)導(dǎo)管介入治療逐漸獲得了臨床越來越多的認(rèn)可。超聲溶栓技術(shù)是溶栓治療的一個重要發(fā)展方向。盡管超聲溶栓的機(jī)制目前仍未得到徹底闡明,但一般認(rèn)為其中一個重要的機(jī)制是超聲激勵體內(nèi)生成的微氣泡或者經(jīng)靜脈注射的微泡產(chǎn)生的空化效應(yīng)。微泡的參與在超聲增強(qiáng)溶栓的過程中起了十分重要的作用,但是由于生物體自身一般缺乏超聲空化需要的空化核微泡,因此,在超聲溶栓過程中引入外源性微泡是非常必要和有利的選擇。經(jīng)體表超聲輔助溶栓研究和應(yīng)用存在的一個重要的問題是臨床上大多數(shù)血栓都是梗阻性的,經(jīng)外周靜脈注射的微泡無法輸送到血栓局部,造成血栓的“空化靶向性”較差。課題組前期研究發(fā)現(xiàn),采用直接血栓內(nèi)注射微泡聯(lián)合體外超聲輻照增強(qiáng)尿激酶溶栓方法產(chǎn)生的溶栓效果,顯著優(yōu)于常規(guī)經(jīng)外周循環(huán)液注射微泡增強(qiáng)的超聲溶栓方法,也優(yōu)于單純血栓內(nèi)注射尿激酶的溶栓效果。血栓內(nèi)注射微泡則可以通過血管內(nèi)導(dǎo)管介入方法實現(xiàn)。經(jīng)體表超聲溶栓存在的另一個問題是大量需要溶栓治療的血栓缺乏合適的體外超聲輻照聲窗。采用血管腔內(nèi)超聲導(dǎo)管溶栓的方法是目前已開始在臨床應(yīng)用的溶栓方法。在歐美,EKOS公司的EkoSonic?血管內(nèi)超聲溶栓導(dǎo)管已獲批準(zhǔn)用于臨床急性肺動脈栓塞和下肢深靜脈血栓等的溶栓治療。但這種超聲溶栓導(dǎo)管由于超聲能量較高,仍可能產(chǎn)生血管壁損傷的副作用,因此需要實時測溫和水冷循環(huán)系統(tǒng)降溫,這就導(dǎo)致導(dǎo)管設(shè)計工藝復(fù)雜,價格昂貴。本課題擬在動物實驗驗證血栓內(nèi)輸注微泡增強(qiáng)超聲溶栓有效性及可行性基礎(chǔ)上,設(shè)計制作一種基于微泡空化的血管腔內(nèi)超聲溶栓導(dǎo)管,綜合血栓內(nèi)微泡超聲溶栓和血管內(nèi)超聲導(dǎo)管聲窗理想的優(yōu)點(diǎn),有望產(chǎn)生更為有效、迅速的溶栓效果。研究目的:1.證實超聲聯(lián)合血栓內(nèi)持續(xù)輸注微泡溶液,可以顯著提高經(jīng)導(dǎo)管介入藥物溶栓效果;2.設(shè)計制作基于微泡空化的新型血管內(nèi)超聲溶栓導(dǎo)管,并證實其可以在持續(xù)輸注微泡溶液的配合下,在體外梗阻性血栓模型中有效增強(qiáng)rt-PA介入溶栓效果。材料與方法:1.主要實驗儀器:⑴改進(jìn)的彩色多普勒超聲診斷儀——VINNO 70(飛依諾科技有限公司,蘇州,中國),配備X4-12L線陣探頭。為溶栓實驗增加的Vflash治療脈沖發(fā)射程序,主要的改進(jìn)為在其常規(guī)的極低機(jī)械指數(shù)(MI=0.04)造影成像軟件的基礎(chǔ)上疊加一個可調(diào)節(jié)治療窗,治療窗內(nèi)治療脈沖受控間斷發(fā)射。本研究中設(shè)定,在每一個治療幀頻時間內(nèi),中心頻率為2.5 MHz、脈沖寬度為5μsec的治療脈沖逐線發(fā)射;治療窗中發(fā)射的治療脈沖線密度約為32/cm,調(diào)整治療窗大小,以完整覆蓋整個血栓栓塞血管節(jié)段。設(shè)定治療脈沖發(fā)射重復(fù)頻率為50 Hz,脈沖作用時間及間歇時間分別設(shè)定為0.5 sec和2.0 sec,MI約為0.50。在水槽微泡空化預(yù)實驗中證實,以上設(shè)置可以有效擊破治療窗中的大部分微泡,而治療窗兩側(cè)的微泡基本無明顯破壞。⑵微量勻速注射泵:Longerpump?TJP-3A,保定蘭格恒流泵有限公司生產(chǎn)。⑶多功能酶標(biāo)儀:型號Varioskan Flash 3001-1723,由美國Thermo Fisher科技公司生產(chǎn)。⑷超聲換能器阻抗分析系統(tǒng):Agilent E4991A,美國Agilent科技有限公司生產(chǎn)。⑸任意信號發(fā)生器:Hantek HDG 2022B,青島漢泰電子有限公司生產(chǎn)。⑹針式水聽器:ONDA HNC-0100,美國ONDA公司生產(chǎn),傳感器直徑為0.1 mm。⑺3D聲場掃描系統(tǒng):英國Precision Acoustics有限公司生產(chǎn)。⑻聲場仿真軟件:COMSOL Multiphysics 4.3a多物理場仿真系統(tǒng),瑞典COMSOL公司開發(fā)。⑼激光共聚焦顯微鏡:萊卡TCS SP5,德國Leica顯微系統(tǒng)有限公司生產(chǎn)。2.主要實驗試劑:⑴微泡:本實驗室自制的包裹全氟丙烷核心氣體的脂膜微泡“脂氟顯”,微泡平均粒徑約為1.95±0.52μm,濃度約為2.0-9.0×109/ml,根據(jù)實驗需要稀釋使用。⑵溶栓藥物:注射用重組組織型纖維蛋白溶酶原激活劑(rt-PA),德國Boehringer Ingelheim藥業(yè)有限公司生產(chǎn)。⑶兔D二聚體酶聯(lián)免疫檢測試劑盒:美國休斯敦Cloud-Clone公司生產(chǎn)。⑷抗凝牛全血:鄭州市九龍生物制品有限公司生產(chǎn),由健康牛全血添加血液保存液抗凝處理制成,4℃保存。⑸抗凝牛新鮮冰凍血漿:鄭州市九龍生物制品有限公司生產(chǎn),由新鮮抗凝牛全血在取血后6 h內(nèi)經(jīng)4℃低速離心取得的血漿,于-30℃以下迅速冰凍制得。試劑存儲于-20℃冰箱,使用前于37℃水浴中快速復(fù)溫。⑹兔抗牛纖維蛋白原抗體:購自北京博奧森生物技術(shù)有限公司。⑺羊抗兔Ig G:購自北京中杉金橋生物技術(shù)有限公司。抗體使用前先用異硫氰酸熒光素(FITC)進(jìn)行標(biāo)記。3.實驗動物:健康新西蘭大白兔40只,均為雄性,體質(zhì)量為2.5-3.0 kg,由第三軍醫(yī)大學(xué)實驗動物中心提供并完成檢疫。4.實驗方法:⑴改進(jìn)的診斷超聲聯(lián)合血栓內(nèi)輸注微泡提高經(jīng)導(dǎo)管介入藥物溶栓動物實驗:(1)建立實驗兔急性梗阻性下腔靜脈血栓模型:模擬“Virchow三部曲”的過程,主要步驟包括血管內(nèi)皮損傷(目標(biāo)血管局部止血鉗鉗夾損傷)、血流狀態(tài)改變(目標(biāo)血管節(jié)段近端使用血管夾夾閉)和血液凝固狀態(tài)改變(目標(biāo)血管局部管腔內(nèi)注入凝血酶)。(2)隨機(jī)對照實驗:40只實驗兔按隨機(jī)分組順序,分別接受以下四組治療,每組10只:超聲Vflash聯(lián)合微泡增強(qiáng)經(jīng)導(dǎo)管rt-PA溶栓(CDT+UT)組、超聲Vflash聯(lián)合微泡溶栓(UT)組、單純經(jīng)導(dǎo)管rt-PA溶栓(CDT)組、生理鹽水對照(Control)組。(3)有效性評價指標(biāo):基于二維超聲及超聲造影所見的梗阻性血栓溶栓效果評分(治療開始30 min及60 min);ELISA法檢測各組實驗兔溶栓前后血漿D二聚體水平;實驗段下腔靜脈血栓病理檢查。(4)安全性觀察:兔近心段下腔靜脈、右心系統(tǒng)、肺動脈及分支血栓形成及繼發(fā)性栓塞發(fā)生情況。⑵新型血管內(nèi)超聲溶栓導(dǎo)管探頭的設(shè)計及聲學(xué)檢測:(1)選取微型超聲換能器并通過阻抗測試篩選合適的激發(fā)頻率。(2)制備單換能器超聲探頭,并對其進(jìn)行適宜頻率激發(fā)下的聲場掃描、電-聲轉(zhuǎn)換測試。(3)利用COMSOL Multiphysics仿真系統(tǒng)對溶栓導(dǎo)管單換能器、換能器組、多組換能器組合聲場進(jìn)行仿真,并優(yōu)化其組合方案。(4)采用被動空化檢測方法檢測超聲溶栓導(dǎo)管探頭微泡空化能力,并通過對散射信號半定量分析方法確定使介質(zhì)中微泡發(fā)生穩(wěn)態(tài)空化及瞬態(tài)空化的適合激勵電壓,為下一步實驗篩選合適參數(shù)。⑶基于微泡空化的血管內(nèi)超聲增強(qiáng)tPA體外溶栓實驗:(1)制備牛全血血栓:潔凈2.0 ml EP管中加入5%氯化鈣溶液33μL(相當(dāng)于氯化鈣1.11 mg),加入1.0 ml牛全血樣品,混勻后靜置于37℃恒溫水箱中水浴3小時,制備牛全血血栓。(2)構(gòu)建梗阻性血栓體外溶栓實驗系統(tǒng)。(3)隨機(jī)對照實驗:實驗共設(shè)以下5組(n=10),分別為血栓內(nèi)超聲聯(lián)合微泡增強(qiáng)t PA溶栓組(US+MB+TPA)、血栓內(nèi)超聲增強(qiáng)tPA溶栓組(US+NS+TPA)、血栓內(nèi)超聲聯(lián)合微泡溶栓組(US+MB)、單純血栓內(nèi)注射tPA溶栓組(TPA alone)及血栓內(nèi)注射生理鹽水對照組(Control)。(4)有效性評價指標(biāo):各組溶栓率。(5)溶栓機(jī)制探討:殘余血栓石蠟包埋切片HE染色光鏡觀察;纖維蛋白免疫熒光染色激光共聚焦顯微鏡觀察。結(jié)果:1.改進(jìn)的診斷超聲聯(lián)合血栓內(nèi)輸注微泡提高經(jīng)導(dǎo)管介入藥物溶栓動物實驗:⑴所有實驗兔均建模成功并完成整個溶栓實驗。實驗結(jié)束后對摘取的實驗兔近心段下腔靜脈、心臟及肺動脈進(jìn)行檢查,均未發(fā)現(xiàn)有局部血栓形成及繼發(fā)血栓栓塞;⑵治療開始30 min時,CDT+UT組溶栓效果評分顯著高于其他各組(P0.05),單純CDT組、單純UT組及對照組溶栓效果評分差異無統(tǒng)計學(xué)意義(P0.05);治療開始60 min時,CDT+UT組及單純CDT組溶栓效果評分均顯著高于UT組及對照組(P0.05);⑶CDT+UT組治療后兔血漿D二聚體濃度顯著升高(P0.05),而其他各組實驗兔血漿D二聚體水平變化均無統(tǒng)計學(xué)意義;⑷病理檢查見CDT+UT組實驗段下腔靜脈血栓幾乎全部或大部分溶解,僅殘存小片狀血栓附著于受損傷較明顯的IVC血管壁上;單純UT組及單純CDT組實驗段下腔靜脈血栓中部可見不同程度部分溶解,因固定、制片過程中血栓退縮,血栓邊緣部分與血管壁脫離,形成不規(guī)則腔隙;對照組血栓中部見小片狀溶解,血栓邊緣與血管壁之間亦可見因血栓退縮形成小片不規(guī)則腔隙。2.新型血管內(nèi)超聲溶栓導(dǎo)管探頭的設(shè)計及聲學(xué)檢測:⑴阻抗測試顯示1.5 MHz為選取的微型超聲換能器的次最佳諧振頻率。單個微型換能器聲場分布可以表征為點(diǎn)聲源,其聲壓隨與換能器表面距離增大迅速降低。在測量范圍內(nèi)峰值聲壓與換能器外加交變電壓(15-52.5 V)呈良好的線性相關(guān),具有良好的電—聲轉(zhuǎn)換效率。⑵聲場仿真結(jié)果顯示,雙換能器背靠背組合成換能器組,可形成繞換能器組一周的較均勻聲場;兩組、多組換能器組沿導(dǎo)管方向并聯(lián)組合后,沿導(dǎo)管長軸方向可形成疊加聲場;當(dāng)換能器組間距為5.0 mm及以下時,沿導(dǎo)管長軸方向可形成較均勻的聲場。⑶被動空化檢測及散射信號半定量分析顯示,當(dāng)換能器聲壓為0.25 MPa時,僅檢測到較小幅值的微泡諧振信號;換能器聲壓為0.50 MPa時,超諧波信號幅度超過噪聲至少3d B,為穩(wěn)態(tài)空化為主;換能器聲壓為0.75 MPa及以上時,特定噪聲分量幅值上升達(dá)二次諧波信號10dB以內(nèi),提示為瞬態(tài)空化為主。3.基于微泡空化的血管內(nèi)超聲增強(qiáng)tPA體外溶栓實驗:⑴血栓內(nèi)超聲聯(lián)合微泡增強(qiáng)t PA溶栓組(US+MB+TPA)溶栓率顯著高于其他各組(P0.05);US+NS+TPA組、TPA alone組溶栓率也顯著高于血栓內(nèi)注射生理鹽水(Control)對照組(P0.05);但US+MB組與血栓內(nèi)注射生理鹽水對照組溶栓率差異無統(tǒng)計學(xué)意義(P=0.142)。⑵殘余血栓HE染色顯示,除血栓內(nèi)注射生理鹽水對照組外,其余各組均可見血栓殘體內(nèi)部范圍、程度不一的疏松改變,以US+MB+TPA組為著;纖維蛋白免疫熒光染色顯示對照組血栓內(nèi)密集交聯(lián)的纖維蛋白網(wǎng)以及網(wǎng)羅于血栓纖維蛋白網(wǎng)中間的細(xì)胞成分,血栓中部導(dǎo)管插入部位附近由于血塊收縮,纖維蛋白條索較血栓內(nèi)部增粗、密集;使用tPA的各組血栓纖維蛋白網(wǎng)結(jié)構(gòu)均可見不同程度松解、斷裂,以接近血栓中部導(dǎo)管插入部位為著。結(jié)論:1.診斷超聲儀發(fā)射的經(jīng)過適當(dāng)改進(jìn)的中等MI、較長脈沖超聲聯(lián)合血栓內(nèi)微泡,可以顯著提高經(jīng)導(dǎo)管介入的藥物溶栓效果。這種綜合溶栓治療方法有望加速血栓清除、進(jìn)一步降低溶栓藥使用總量,從而降低溶栓相關(guān)并發(fā)癥發(fā)生的風(fēng)險。2.基于微泡空化的新型血管內(nèi)超聲溶栓導(dǎo)管,綜合利用了血栓內(nèi)微泡增強(qiáng)的超聲溶栓作用和血管內(nèi)超聲直接接觸作用于血栓的優(yōu)點(diǎn),可以有效增強(qiáng)rt-PA的溶栓作用。3.超聲聯(lián)合血栓內(nèi)微泡增強(qiáng)藥物溶栓的機(jī)制為空化效應(yīng)促進(jìn)溶栓藥物對血栓的滲透、加速其纖溶進(jìn)程,并促進(jìn)纖維蛋白降解產(chǎn)物向周圍的彌散。
[Abstract]:Background: thrombosis and embolism are the pathological basis of a large number of cardiovascular and cerebrovascular diseases. At present, intravenous thrombolytic therapy, such as tPA, is the mainstream treatment for these diseases. There is a strict time window for thrombolytic therapy through venous thrombolysis. The safety and effectiveness of thrombolytic therapy are also greatly improved. Transcatheter interventional therapy is a current clinical thrombotic disease. Another kind of treatment. In recent years, with the use of more effective new interventional embolectomy catheter, it has been shown that the combination of mechanical thrombolysis combined with systemic or local injection of thrombolytic drugs can improve the early repassage rate and improve the prognosis of the obstructed vessels. Therefore, interventional therapy has gradually gained more and more recognition. Although the mechanism of ultrasonic thrombolysis has not been thoroughly clarified, one of the most important mechanisms is that the microbubbles generated by ultrasonic stimulation or the cavitation effect produced by the microbubbles injected through the vein are important. However, the introduction of exogenous microbubbles in the process of ultrasonic thrombolysis is a necessary and beneficial choice because the organism itself generally lacks the need for ultrasonic cavitation. Therefore, an important problem in the study and application of thrombolytic assisted thrombolysis is that most of the thrombus on the bed is obstructive and transstatic through peripheral static. The microbubbles injected into the vein can not be transported to the part of the thrombus, and the "cavitation targeting" of the thrombus is poor. In the previous study, we found that the thrombolytic effect produced by the direct thrombus injection combined with in vitro ultrasound irradiation enhanced the thrombolytic method of urokinase was significantly better than that of the conventional percutaneous injection of microbubble enhanced ultrasound thrombolysis. It is also better than the thrombolytic effect of intravascular injection of urokinase. The intravascular catheter intervention can be achieved by intravascular injection of microbubbles in thrombus. Another problem of thrombolytic thrombolytic therapy is that a large number of thrombolytic thrombolytic patients lack appropriate external ultrasound irradiation windows. The method of thrombolytic therapy by intravascular ultrasound catheter is the goal of the thrombolytic therapy. EKOS's EkoSonic? Intravascular ultrasound thrombolytic catheter has been approved for thrombolytic therapy for acute pulmonary embolism and deep vein thrombosis in the lower extremities in Europe and America. However, the ultrasonic thrombolytic catheter can still produce the side effects of vascular wall injury due to high ultrasonic energy. On the basis of the effectiveness and feasibility of the intravascular infusion of microbubble enhanced ultrasound thrombolytic thrombolysis, a kind of intravascular supersonic thrombolytic catheter based on microbubble cavitation is designed and fabricated on the basis of the effectiveness and feasibility of the intravascular infusion microbubble enhanced ultrasound thrombolytic thrombolysis. The ideal advantage of the intravascular ultrasound catheter is expected to produce more effective and rapid thrombolytic effects. 1. it is proved that continuous infusion of microbubbles in ultrasound combined with thrombus can significantly improve the thrombolytic effect of transcatheter interventional drugs; (2.) a new intravascular ultrasound thrombolytic catheter based on microbubble cavitation is designed and proved to be possible Under the combination of continuous infusion microbubble solution, the effect of rt-PA interventional thrombolysis was effectively enhanced in the external obstructive thrombus model in vitro. Materials and methods: 1. main experimental instruments: (1) the improved color Doppler ultrasonic diagnostic instrument - VINNO 70 (fleno Technology Co., Suzhou, China), equipped with X4-12L linear array probe. The increase of Vflash for thrombolytic experiments The main improvement is to superimpose an adjustable therapeutic window on the basis of its conventional extremely low mechanical index (MI=0.04) imaging software, and to treat pulse controlled intermittent launch in the treatment window. In this study, a therapeutic pulse with a center frequency of 2.5 MHz and a pulse width of 5 sec within each frame frequency time is set in this study. The pulse line emission of the treatment window was about 32/cm, the treatment window was adjusted to adjust the size of the treatment window to complete the whole thromboembolic vascular segment. The repetition frequency of the pulse emission was set to 50 Hz, the pulse time and the interval time were set to 0.5 sec and 2 sec respectively, and MI was about 0.50. in the trough microbubble cavitation test. In fact, the above setting can effectively break down most of the microbubbles in the treatment window, and the microbubbles on both sides of the treatment window have no obvious damage. 2. Micro speed injection pump: Longerpump? TJP-3A, Baoding Lange constant flow pump Co., Ltd. (3) multi function enzyme scale instrument: model Varioskan Flash 3001-1723, produced by Thermo Fisher technology company in the United States. Acoustic transducer impedance analysis system: Agilent E4991A, American Agilent Technology Co., Ltd. production. Arbitrary signal generator: Hantek HDG 2022B, Qingdao Han Tai Electronics Co., Ltd. production. The needle type hydrophone: ONDA HNC-0100, American ONDA company production, sensor diameter is 0.1 mm. 3D sound field scanning system: UK Precision Limited COMSOL Multiphysics 4.3a multi physical field simulation system, Sweden COMSOL Co., Ltd. development. Laser confocal microscope: Leica TCS SP5, German Leica microsystem Co., Ltd. to produce.2. main experimental reagent: (1) microbubble: lipid membrane microbubble "lipid membrane" made in our laboratory for parcel perfluoropropane core gas The average particle size of the microbubble is about 1.95 + 0.52 m, and the concentration is about 2.0-9.0 x 109/ml, which is diluted in accordance with the needs of the experiment. (2) thrombolytic drugs: recombinant tissue type fibrinolytic enzyme activator (rt-PA) and German Boehringer Ingelheim Pharmaceutical Co., Ltd. (3). (3) the enzyme linked immunoassay kit for rabbit D two polymer: Cloud-C of Houston, USA Lone production. 4. Whole blood of anticoagulant cattle: produced by Zhengzhou Kowloon Biological Products Co., Ltd., made of healthy cattle whole blood with Anticoagulation Solution anticoagulant treatment, preserved at 4 C. Fresh frozen plasma of anticoagulant cattle: Zhengzhou Jiulong Biological Products Co., Ltd., obtained by fresh anticoagulant bovine whole blood in 6 h after taking blood at 4 degrees centigrade after taking blood Plasma, quickly frozen below -30 C. The reagent is stored at -20 centigrade refrigerator and quickly reheated at 37 centigrade water bath before use. The Rabbit anti bovine fibrinogen antibody: purchased from Beijing Boosen Biotechnology Co., Ltd. and purchased from rabbit Ig G: from Beijing Zhongshan Jinqiao Biotechnology Co., Ltd.. Before the use of antibody, isothiocyanate (FI TC test animals: 40 healthy New Zealand white rabbits, all of which were male and body mass of 2.5-3.0 kg, were provided by the laboratory animal center of Third Military Medical University and completed the quarantine.4. experimental method: (1) improved diagnostic ultrasound combined with thrombus infusion microbubbles to improve the experimental thrombolytic experiment of percutaneous thrombolytic therapy: (1) the establishment of experimental rabbit acute stem A model of hindrance inferior vena cava thrombosis: the process of simulating the "Virchow Trilogy", the main steps include vascular endothelial injury (the local hemostasis clamp injury of the target vessel), the change of blood flow state (the use of blood vessel clamp in the near end of the target vascular segment) and the change of blood coagulation state (thrombin injected into the local lumen of the target vessel). (2) random control Experiment: 40 rabbits were treated in the following four groups according to random grouping, 10 in each group: ultrasound Vflash combined with microbubble enhanced transcatheter rt-PA thrombolysis (CDT+UT), ultrasound Vflash combined with microbubble thrombolysis (UT), simple transcatheter rt-PA thrombolysis (CDT), and saline control (Control). (3) based on two-dimensional ultrasound and The thrombolytic effect score of obstructive thrombus (30 min and 60 min) was observed by contrast echocardiography; ELISA method was used to detect the level of plasma D two polymer before and after thrombolysis in the experimental rabbits; the pathological examination of the inferior vena cava thrombus in the experimental segment. (4) safety observation: the inferior vena cava, the right heart system, the pulmonary artery and branch thrombosis and secondary embolism in the rabbit The design and acoustic detection of the new intravascular ultrasound thrombolytic catheter probe: (1) select the micro ultrasonic transducer and select the appropriate excitation frequency through the impedance test. (2) the single transducer ultrasonic probe is prepared, and the sound field scanning under the appropriate frequency excitation, the electrical acoustic conversion test. (3) using the COMSOL Multiphysics simulation system The single transducer, transducer group, multi group transducer combination sound field is simulated and its combination scheme is optimized. (4) the passive cavitation detection method is used to detect the microbubble cavitation ability of ultrasonic thrombolytic probe, and a suitable method for determining the steady cavitation and transient cavitation of microbubbles in the medium is determined by the method of semi quantitative analysis of the scattered signal. Stimulating voltage, selecting suitable parameters for the next experiment. (3) intravascular ultrasound enhanced tPA thrombolytic experiment based on microbubble cavitation: (1) preparation of bovine whole blood thrombus: 5% calcium chloride solution 33 mu L (equivalent to calcium chloride 1.11 mg) in a clean 2 ml EP tube, and 1 ml bovine whole blood samples, and after mixing at 37 centigrade constant temperature water tank for 3 hours, To prepare whole blood thrombus of cattle. (2) construct an in vitro thrombolytic experimental system for obstructive thrombus. (3) randomized controlled experiment: the following 5 groups (n=10) were set up, including thrombus ultrasound combined with microbubble enhanced T PA thrombolysis group (US+MB+TPA), thrombolytic thrombolytic thrombolysis group (US+NS+ TPA), thrombolytic ultrasound combined with microbubble thrombolysis group (US+MB), and simple intravascular injection TPA thrombolytic group (TPA alone) and thrombolytic injection of physiological saline control group (Control). (4) evaluation index of effectiveness: thrombolytic rate in each group. (5) thrombolytic mechanism: residual thrombus embedded section HE staining light microscopy; fibrin immunofluorescence staining laser confocal microscope observation. Results: 1. improved diagnostic ultrasound combined thrombus infusion The microbubbles improved the thrombolytic experiment of transcatheter interventional drugs: (1) all experimental rabbits were successfully modeled and completed the whole thrombolytic experiment. After the experiment, the inferior vena cava, heart and pulmonary arteries of the rabbits were examined. No local thrombus formation and secondary blood Se were found. (2) group CDT+UT thrombolysis at the beginning of 30 min treatment The score of effect was significantly higher than that of other groups (P0.05). There was no significant difference in thrombolytic effect between simple CDT group, simple UT group and control group (P0.05). The thrombolytic effect score of group CDT+UT and pure CDT group was significantly higher than that of group UT and control group (P0.05) at the beginning of 60 min treatment. (3) the concentration of D two polymer in rabbit plasma after treatment was significantly higher (P0.05). There was no significant difference in the level of D two polymer in the plasma of the rabbits in other groups. (4) pathological examination showed that the inferior vena cava thrombus was almost all or most dissolved in the experimental segment of group CDT+UT, only the remnants of small fragment thrombosis were attached to the more obvious IVC vascular wall of the injured group, and the central part of the inferior vena cava thrombus in the pure UT group and the single pure CDT group was seen in the middle of the vena cava thrombus. With the same degree of dissolution, the thrombus was reduced and the thrombus was separated from the vessel wall in the process of production. The central part of the thrombus in the control group was small dissolving, and the design and sound of the new intravascular ultrasound thrombolytic probe probe between the thrombus edge and the blood vessel wall was also seen between the thrombus and the blood vessel wall formed in the irregular lacunae of.2.. Test: (1) the impedance test shows that 1.5 MHz is the second best resonant frequency of the selected micro ultrasonic transducer. The sound field distribution of a single micro transducer can be characterized as a point sound source, and the sound pressure decreases rapidly with the surface distance of the transducer. The peak sound pressure in the measurement range is in good linearity with the applied alternating voltage (15-52.5 V) of the transducer. The results of sound field simulation show that the double transducer is combined into a transducer group with back to back, which can form a more uniform sound field around the transducer group for a week. The two groups of transducer groups can form superposition sound field along the direction of the catheter along the direction of the catheter in parallel, and the interval between the transducers is 5 mm and the two groups are in the direction of the transducer. At the next time, a more uniform sound field can be formed along the long axis of the duct. (3) the semi quantitative analysis of passive cavitation detection and scattering signal shows that when the transducer's sound pressure is 0.25 MPa, only a small amplitude microbubble resonant signal is detected. When the transducer's sound pressure is 0.50 MPa, the amplitude of the super harmonic signal exceeds the noise at least 3D B, which is the main steady cavitation; the transducer is the main transducer. When the sound pressure is above 0.75 MPa and above, the amplitude of the specific noise component rises to two times the harmonic signal within 10dB, suggesting that the transient cavitation is the main.3.

【學(xué)位授予單位】：第三軍醫(yī)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：R454.3

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