动脉瘤射频导管消融中多物理场耦合的计算与实验研究

发布时间：2017-12-31 17:31

  本文关键词：动脉瘤射频导管消融中多物理场耦合的计算与实验研究　出处：《北京工业大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 动脉瘤 射频消融 温度场 有限元仿真

【摘要】：动脉瘤作为一种常见而危险的心脑血管疾病是医学领域的研究热点,特别是复杂动脉瘤的治疗是一个富有挑战性的医学问题。近年来动脉瘤的介入治疗术以其创伤性小、费用低、疗效好等特点已被广泛应用于临床。但对于复杂的动脉瘤,介入治疗会出现支架脱落、生物相容性问题及动脉瘤破裂等严重的并发症。射频导管消融是将很细的导管从颈部、大腿根部植入血管内,到达心脏等靶组织,然后释放射频电流,从而对“病灶”进行一次性的消融。本课题将介入式热疗方法和动脉瘤栓塞机理结合起来,基于射频导管消融术提出了一种新的方法治疗动脉瘤,即采用射频导管消融使动脉瘤瘤腔内的血液快速凝固,形成血栓,阻止血液流向动脉瘤腔内,进而逐步纤维化,最终导致动脉瘤萎缩,从而达到治疗动脉瘤的目的。为了证明该方法的可行性,本研究通过有限元数值仿真和离体模型实验两种方法进行验证。在二维和三维模型的情况下进行数值研究,分别研究了不同治疗参数(包括不同激励方式、电极形状、消融方式等)对动脉瘤射频消融的温度场、流场的影响,分析消融范围是否适合动脉瘤的治疗。数值仿真的结果表明:在直管动脉瘤三维模型中,温度场呈圆形,在加热200s,电场强度为15V/mm时,最高温度为101.52℃,动脉瘤腔的绝大部分都被60℃轮廓图所包围,但动脉瘤左侧的小范围的动脉壁与组织也被60℃轮廓图所涵盖,可能会造成小范围的组织损伤。电极存在时,血管内有电极处的血流速度升高0.04m/s左右,无电极处的流场速度降低0.1 m/s左右。瘤腔内的流速较低有利于动脉瘤瘤腔内温度升高,60℃轮廓图的形状有利于动脉瘤腔内的血液凝固,这从温度场与流场两个方面证明射频消融治疗动脉瘤的可行性。同时本研究利用三维打印构建了理想的三维模型,经过二次倒模得到透明的三维模型。利用微波消融仪自带的水泵创建循环系统,进行离体模型实验,观察动脉瘤的温度上升状况。研究表明,当天线在动脉瘤口颈处时,瘤腔内温度上升较小,在40W和60W,5min时,都约为1.6℃左右;80W时上升高于4℃。当天线在动脉瘤腔内时,瘤腔内的温度上升较快,在40W,5min时,为8℃左右,并且随功率的升高,温升变化不大。当天线在动脉瘤腔内时,在三种功率下温度都上升11℃左右,温度上升较大,有利于动脉瘤的消融。本研究表明类圆形的动脉瘤适合利用射频消融方法进行治疗,且在激励为15V/mm,消融时间为200s时,温度场既能覆盖整个动脉瘤又对外部组织损伤较小且对动脉内的血流动力学状况影响较小,可以作为动脉瘤射频消融的最优治疗参数。在载瘤动脉为弯管时及囊状动脉瘤时,可以利用射频消融联合支架来进行动脉瘤的治疗。
[Abstract]:As a common and dangerous cardiovascular and cerebrovascular disease, aneurysm is a hot topic in the field of medicine. In particular, the treatment of complex aneurysms is a challenging medical problem. In recent years, interventional treatment of aneurysms is less traumatic and less costly. The characteristics of good curative effect have been widely used in clinic, but for complex aneurysms, stent shedding will occur after interventional therapy. Serious complications such as biocompatibility and ruptured aneurysms. Radiofrequency catheter ablation (RFCA) is the implantation of a very thin catheter from the neck and the root of the thigh into the blood vessel to reach the target tissue such as the heart and then release the radiofrequency current. In this paper, we combine interventional hyperthermia with the mechanism of aneurysm embolization, and propose a new method for the treatment of aneurysm based on radiofrequency catheter ablation. That is, radiofrequency catheter ablation can rapidly coagulate the blood in the aneurysm cavity, form thrombus, prevent the blood flow into the aneurysm cavity, and then gradually fibrosis, and finally cause the aneurysm atrophy. In order to prove the feasibility of this method, the treatment of aneurysm can be achieved. This study was verified by finite element numerical simulation and in vitro model experiment. In the case of 2D and 3D models, different treatment parameters (including different excitation modes) were studied. The effect of electrode shape and ablation method on the temperature field and flow field of radiofrequency ablation of aneurysms is analyzed. The numerical simulation results show that the ablation range is suitable for the treatment of aneurysms. The temperature field is circular. When the heating time is 200 s and the electric field intensity is 15 V / mm, the highest temperature is 101.52 鈩，

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