Finally, the system of vascular interventional radiology simulator is discussed by integrating all presented techniques and designing a trackball mouse based hardware sensors. Training experiments demonstrate that the presented techniques benefit rapid development of realistic and interactive vascular interventional radiology simulators. / Fourth, in order to clearly visualize vascular networks and the placement of instruments while treating the lesion, a physics-based simulation for angiography procedure is presented based on navier-stokes equation and semi-lagrangian method. The multi-scale vessel grid is reconstructed for flow distribution, and point sprites based rendering is adopted to preserve real-time visualization of the procedure. The experiments demonstrate that our results are more realistic compared to previous methods and are closer to the real angiography procedure. / In order to build a high fidelity interventional simulator for physician training and surgery planning, accurate reconstruction of three dimensional vascular network, real-time simulation of angiographic medium propagation and physics-based simulation of interaction between surgical instruments and vessel wall are absolutely indispensable. Thus, first, a methodology for geometric vascular modeling is proposed. As the reconstructed models are essential for many subsequent applications such as deformable modeling and visualization, a series of methods are proposed based on the parallel transport frames in order to maintain high mesh quality of these models. An improved bifurcation modeling method and two novel trifurcation modeling methods are developed based on 3D Bezier curve segments in order to ensure the continuous surface transition at furcations. To solve the twisting problem caused by frame mismatch of two successive furcations, a frame blending scheme is implemented. A curvature based adaptive sampling scheme combined with a mesh quality guided frame tilting algorithm is developed to construct an evenly distributed, non-concave and self-intersection free surface mesh. In terms of surface mesh quality criteria, our methodology can generate vascular models with better mesh quality than previous methods. / Second, we extend our geometric modeling method for illustrative visualization of vasculature, which is an indispensable component in medical education and training. Illustration of vasculature accentuates depth perception and provides a specific manner to identify the branching pattern and topology of vascular structure, which is crucial for therapy planning and real surgery in order to give an effective treatment. With advanced GPU acceleration techniques including render to texture (RTT) , framebuffer object (FBO) and fast image convolution, a real-time visualization can be achieved. / Third, an interactive simulation of angioplasty procedure is reported. To achieve an efficient modeling of soft tissue deformation and virtual device mechanics, mass spring models are adopted to construct the deformable models of vessel wall and stent. By designing a quasi-equilateral triangular mesh model of blood vessel and stent, a linear spring coefficients setting method is adopted to achieve the same accuracy compared with finite element method. With the employment of Physics Processing Unit (PPU), a real-time simulation of the interaction between blood vessel wall and surgical device is developed for vascular interventional radiology simulation. / Vascular diseases have been the leading cause of death worldwide. Interventional procedures are an increasingly promising therapy for treating vascular diseases, which are usually done by a guidewire-catheter combination under the fluoroscopic guidance. However, due to the complicated vascular network, bending of surgical instruments and the risk of vessel injury, these techniques need to be performed by highly trained and experienced specialists. Virtual reality based training of these procedures offers high flexibility and cost effective alternative. Furthermore, it allows training evaluation and accelerates learning process without risk to patients, therefore has distinct advantages than traditional training methods on animals or cadavers. / Guo, Jixiang. / Advisers: Pheng-Ann Heng; Tien-Tsin Wong. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 97-111). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

A revascularização da oclusão arterial ilíaca crônica com implante de endoprótese vascular é uma nova modalidade terapêutica para os pacientes com aterosclerose obliterante das extremidades. Os objetivos deste trabalho são verificar: os resultados clínico e radiológico do tratamento percutâneo com implante de endoprótese vascular nas oclusões arteriais crônicas do território ilíaco; a influência da aterosclerose e seus principais fatores de risco; os principais sintomas clínicos segundo os estágios de Fontaine e o comportamento das endopróteses vasculares, avaliando as permeabilidades primária e secundária. Foram estudados 67 pacientes, com 69 oclusões arteriais ilíacas crônicas, submetidos a intervenção de janeiro de 1992 a dezembro de 1998, por meio de avaliação clínica, Doppler com medida do índice tornozelo/braço e arteriografia dos membros inferiores. As revascularizações arteriais ilíacas foram realizadas sob anestesia local, utilizando-se as endopróteses tipos Wallstent® e Cragg®. O índice de sucesso técnico foi de 97,10%. A mediana do período de internação foi de dois dias e as complicações mais importantes foram tromboses arteriais (2,99%), roturas arteriais (2,99%) e embolia poplítea (1,49%). O índice tornozelo/braço pré e pós-procedimento demonstrou um incremento, estatisticamente significante, após a intervenção (P = 0,0001), e os eventos durante o seguimento foram as estenoses (5,97%) e tromboses (8,96%) das endopróteses. Houve algum grau de melhora clínica em 92,5% dos pacientes. Os casos que não apresentaram melhora tiveram associação, estatisticamente significante, com cardiopatia associada (P = 0,003) e estágios III e IV de Fontaine (P = 0,022). Não houve associação, estatisticamente significante, entre os fatores analisados e permeabilidade das endopróteses vasculares. A revascularização percutânea com implante de endopróteses vasculares nas oclusões arteriais ilíacas crônicas, demonstrou apresentar bons índices de permeabilidades primária (75%) e secundária (95%) durante o período médio de 30 meses de acompanhamento. / Arterial recanalization with percutaneous transluminal angioplasty and implantation of a vascular endoprosthesis in an occluded iliac artery is a ew therapeutic modality for those patients with obliterative atherosclerosis of the extremities. The objectives of this work are to demonstrate the clinical and radiological results of treatment of chronic occlusions of the iliac arteries; to demonstrate the effects of atherosclerosis as well as primary risk factors; to evaluate the primary clinical symptoms using the Fontaine classification and to study the effectiveness of the vascular endoprostheses with primary and secondary patency rates. Sixty-seven patients with 69 chronically occluded iliac arteries underwent percutaneous intervention from January 1992 throught December 1998. Evaluations included clinical assessment, Doppler examinations with ankle/brachial indexes and bilateral lower extremity arteriograms. The iliac artery recanalizations were performed under local anesthesia and using Wallstent® and Cragg® vascular endoprostheses. Technical success rate was 97.10%. The mean hospitalization time was two days and major complications included arterial thrombosis (2.99%), arterial rupture (2.99%) and popliteal embolization (1.49%). The prior and post procedure ankle/brachial indexes demonstrated a statistically significant increase following intervention (P = 0.0001). During follow-up there was 5.97% of stenosis and 8.96% thrombosis of the endoprostheses. There was clinical improvement in 92.42% of patients. Patients that did not show clinical improvement had association with coronary disease (P = 0.003), Fontaine stages III and IV (P = 0.022) and arterial hypertension (P = 0.087). There was no statistically significant factor associated with lower patency of the endoprostheses. Percutaneous revascularization of chronically occluded iliac arteries with utilization of vascular endoprostheses has shown good primary (75%) and secondary (95%) patency rates during 30 months of mean follow-up period.

A revascularização da oclusão arterial ilíaca crônica com implante de endoprótese vascular é uma nova modalidade terapêutica para os pacientes com aterosclerose obliterante das extremidades. Os objetivos deste trabalho são verificar: os resultados clínico e radiológico do tratamento percutâneo com implante de endoprótese vascular nas oclusões arteriais crônicas do território ilíaco; a influência da aterosclerose e seus principais fatores de risco; os principais sintomas clínicos segundo os estágios de Fontaine e o comportamento das endopróteses vasculares, avaliando as permeabilidades primária e secundária. Foram estudados 67 pacientes, com 69 oclusões arteriais ilíacas crônicas, submetidos a intervenção de janeiro de 1992 a dezembro de 1998, por meio de avaliação clínica, Doppler com medida do índice tornozelo/braço e arteriografia dos membros inferiores. As revascularizações arteriais ilíacas foram realizadas sob anestesia local, utilizando-se as endopróteses tipos Wallstent® e Cragg®. O índice de sucesso técnico foi de 97,10%. A mediana do período de internação foi de dois dias e as complicações mais importantes foram tromboses arteriais (2,99%), roturas arteriais (2,99%) e embolia poplítea (1,49%). O índice tornozelo/braço pré e pós-procedimento demonstrou um incremento, estatisticamente significante, após a intervenção (P = 0,0001), e os eventos durante o seguimento foram as estenoses (5,97%) e tromboses (8,96%) das endopróteses. Houve algum grau de melhora clínica em 92,5% dos pacientes. Os casos que não apresentaram melhora tiveram associação, estatisticamente significante, com cardiopatia associada (P = 0,003) e estágios III e IV de Fontaine (P = 0,022). Não houve associação, estatisticamente significante, entre os fatores analisados e permeabilidade das endopróteses vasculares. A revascularização percutânea com implante de endopróteses vasculares nas oclusões arteriais ilíacas crônicas, demonstrou apresentar bons índices de permeabilidades primária (75%) e secundária (95%) durante o período médio de 30 meses de acompanhamento. / Arterial recanalization with percutaneous transluminal angioplasty and implantation of a vascular endoprosthesis in an occluded iliac artery is a ew therapeutic modality for those patients with obliterative atherosclerosis of the extremities. The objectives of this work are to demonstrate the clinical and radiological results of treatment of chronic occlusions of the iliac arteries; to demonstrate the effects of atherosclerosis as well as primary risk factors; to evaluate the primary clinical symptoms using the Fontaine classification and to study the effectiveness of the vascular endoprostheses with primary and secondary patency rates. Sixty-seven patients with 69 chronically occluded iliac arteries underwent percutaneous intervention from January 1992 throught December 1998. Evaluations included clinical assessment, Doppler examinations with ankle/brachial indexes and bilateral lower extremity arteriograms. The iliac artery recanalizations were performed under local anesthesia and using Wallstent® and Cragg® vascular endoprostheses. Technical success rate was 97.10%. The mean hospitalization time was two days and major complications included arterial thrombosis (2.99%), arterial rupture (2.99%) and popliteal embolization (1.49%). The prior and post procedure ankle/brachial indexes demonstrated a statistically significant increase following intervention (P = 0.0001). During follow-up there was 5.97% of stenosis and 8.96% thrombosis of the endoprostheses. There was clinical improvement in 92.42% of patients. Patients that did not show clinical improvement had association with coronary disease (P = 0.003), Fontaine stages III and IV (P = 0.022) and arterial hypertension (P = 0.087). There was no statistically significant factor associated with lower patency of the endoprostheses. Percutaneous revascularization of chronically occluded iliac arteries with utilization of vascular endoprostheses has shown good primary (75%) and secondary (95%) patency rates during 30 months of mean follow-up period.