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標題: | 創新複合式血液分流器的設計與開發 Design and Development of Novel Hybrid Flow Diverter |
作者: | Tzu-Yun Chou 周子芸 |
指導教授: | 蕭浩明(Hao-Ming Hsiao) |
關鍵字: | 有限元素法,血液動力學,鎳鈦合金,複合式血液分流器,顱內動脈瘤,壁面剪應力, Finite element analysis,Hemodynamics,Nitinol,Hybrid flow diverter,Intracranial aneurysm,Wall shear stress, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 顱內動脈瘤為血管壁弱化導致局部病理性擴張的腦血管疾病,隨著動脈瘤擴大,其可能壓迫到鄰近組織,或破裂造成嚴重併發症甚至猝死。顱內動脈瘤治療的標準方法為開顱手術及白金線圈栓塞術,目的為阻擋血液進入動脈瘤以降低動脈瘤破裂的風險。近年來新的治療方法「血液分流器」漸漸普及,其部署於母血管以導引血流方向,將動脈瘤阻隔於血液循環外,但仍有許多臨床問題待解。本研究提出治療顱內動脈瘤的創新介入性裝置「Hybrid血液分流器」,此概念乃全球首創,使血液分流器擁有多種密度的網眼,其中密的網眼面向動脈瘤,確保阻斷進入動脈瘤的血流量,與母血管接觸的部分,則為較疏的網眼,避免阻塞母血管。本文著眼於創新性Hybrid血液分流器的開發,從設計最佳化到製程、部署過程的有限元素分析及部署前後的血液動力學分析,並實際製造出雛型品。參數化設計將網眼密度分配進行了最佳化的調整,接著以有限元素模型進行Hybrid血液分流器製造過程及部署至動脈瘤母血管的模擬,以分析Hybrid血液分流器的機械性質,並以Goodman疲勞安全係數分析來評估Hybrid血液分流器的抗疲勞強度。最後本研究建立了血液動力學模型分析Hybrid血液分流器的性能,模擬結果顯示部署Hybrid血液分流器能阻擋75%至95%流入動脈瘤的血液,動脈瘤囊的壁面剪應力大幅下降,動脈瘤內的平均滯留時間也提升為原本的12.47倍,延長淤滯可促進血栓形成,血液流場狀態更穩定,大幅降低動脈瘤破裂的風險;同時母血管的網眼較疏,低壁面剪應力面積也較少,可以避免血管狹窄。模擬結果符合預期後,本研究以鎳鈦合金無縫微管進行雷射切削加工,再進行熱處理定型、噴砂、電解拋光等處理,進行Hybrid血液分流器雛型品的製造,並將雛型品部署於血管模型作為概念展示。 An intracranial aneurysm is a cerebrovascular disorder in which structural weakening of the wall media causes localized pathological dilation of the blood vessel. As an aneurysm grows, it puts pressure on adjacent structures and may eventually rupture, leading to severe complications or even sudden death. The standard treatments for intracranial aneurysms include traditional craniotomy and endovascular coiling. The purpose of these treatments is to stop the blood flow into the aneurysm to reduce the risk of rupture. In recent years, another new device, called “flow diverter”, has gained popularity. It is placed in the parent artery in order to divert the blood flow away from the weakened area, isolating aneurysms from normal circulation. Although flow diverter stents have great potential, there remains clinical issues to be resolved. In this research, a novel interventional device concept for treatments of intracranial aneurysm, called “hybrid flow diverter”, is proposed. The hybrid flow diverter concept is the first of its kind in the world. The hybrid flow diverter is designed to have variable metal densities, with the denser side facing the aneurysm to block the blood supply and the lighter side facing the parent artery to prevent in-stent stenosis. Development of hybrid flow diverter is proposed in this research, including optimal design, finite element analysis of manufacturing and deployment processes, hemodynamic analysis before and after deployment, and manufacturing processes. Parametric design methodology was used to achieve the optimal design. Finite element models were developed to analyze the mechanical behavior of the device during manufacturing and deployment processes. Goodman life analysis was used to evaluate the fatigue resistance of hybrid flow diverter. Hemodynamic models were established to evaluate the performance of hybrid flow diverter. Results show that hybrid flow diverter stops 75%-95% blood flow into the aneurysm. Wall shear stress in aneurysm sac drops significantly after deployment of hybrid flow diverter. Average residence time within the aneurysm is increased by 12.47 times, elongating the stasis and producing thrombogenic conditions. The blood flow field is more stable, significantly reducing the risk of aneurysm rupture. Low wall shear stress area in parent artery is reduced due to the lighter side of hybrid flow diverter, thus preventing in-stent thrombosis or stenosis. After expected results of computational modeling, a pulsed-fiber optic laser, expansions, heat treatments, and polishing technologies were used on nitinol seamless tube to make the first prototype of hybrid flow diverter. The hybrid flow diverter was then deployed in an aneurysm model for demonstration. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/77597 |
DOI: | 10.6342/NTU201802098 |
全文授權: | 未授權 |
顯示於系所單位: | 機械工程學系 |
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