Patient-specific bronchoscopy visualization through BRDF estimation and disocclusion correction

This paper presents an image-based method for virtual bronchoscope with photo-realistic rendering. The technique is based on recovering bidirectional reflectance distribution function (BRDF) parameters in an environment where the choice of viewing positions, directions, and illumination conditions are restricted. Video images of bronchoscopy examinations are combined with patient-specific three-dimensional (3-D) computed tomography data through two-dimensional (2-D)/3-D registration and shading model parameters are then recovered by exploiting the restricted lighting configurations imposed by the bronchoscope. With the proposed technique, the recovered BRDF is used to predict the expected shading intensity, allowing a texture map independent of lighting conditions to be extracted from each video frame. To correct for disocclusion artefacts, statistical texture synthesis was used to recreate the missing areas. New views not present in the original bronchoscopy video are rendered by evaluating the BRDF with different viewing and illumination parameters. This allows free navigation of the acquired 3-D model with enhanced photo-realism. To assess the practical value of the proposed technique, a detailed visual scoring that involves both real and rendered bronchoscope images is conducted

Modelagem de aparência baseada em biofísica para tecidos do fígado humano

A representação gráfica de tecidos humanos é uma importante demanda para aplicações de áreas como ensino, entretenimento e treinamento médico. Frequentemente, a simulação de tais materiais envolve considerar características dinâmicas vinculadas as suas funções no corpo humano e que influenciam diretamente também em sua aparência. O fígado humano, apesar de um órgão interno, portanto, de difícil acesso, possui diferentes modelos de representação apresentados na literatura da Computação Gráfica (CG). Entretanto, tais modelos desconsideram as influências das propriedades ópticas dos elementos biofísicos que compõem os tecidos hepáticos, fornecendo assim, aproximações cuja parametrização controla apenas um estado específico do material orgânico, em geral, avaliando visualmente o resultado. O presente trabalho apresenta a modelagem dos tecidos do fígado humano através da descrição dos elementos biofísicos que compõem suas camadas estruturais: o parênquima e a cápsula de Glisson. Além disso, tal modelo implementa a interação luz-matéria em termos de eventos como a absorção, dispersão, reflexão e transmissão de luz, como processos biológicos que produzem a coloração específica do material, ou seja, sua resposta espectral. A abordagem matemática do modelo é definida como numérica e estocástica, para a qual é apresentada uma solução para garantir sua convergência. Reunindo recentes descrições sobre a estrutura dos tecidos hepáticos e sua interação com a luz apresentadas na literatura biomédica, o modelo desenvolvido representa a primeira solução baseada em biofísica para um órgão interno do corpo humano. Os resultados de imagens geradas através do modelo são apresentados junto a fotografias de tecidos análogos, assim como, curvas de respostas espectrais e espaciais disponíveis na literatura biomédica são comparadas com as produzidas pelo modelo desenvolvido, evidenciando a capacidade deste na representação gráfica do tecido hepático

Bleeding Control Using Multiple Amputee Trauma Trainer In Medical Simulation Comparison Of Movement Versus Non-movement In Training

Army first responders, specifically Combat Medics and Combat Lifesavers, provide medical intervention while in the field. Didactic as well as hands-on training helps to prepare these first responders, and one module they receive involves bleeding control. First responders are taught to use the Combat Application Tourniquet® (CAT® ) to stop bleeding from limbs subjected to severe injury such as amputation, gunshot, or severe lacerations. A training aid like the Multiple Amputee Trauma Trainer™ (MATT™) simulator provides tourniquet training using a lifelike bilateral lower limb amputee. In addition, MATT™ combines movement and resistance while the first responder applies the tourniquet, mimicking conditions one would see in a real situation. This research describes tourniquet history, appropriate usage, field tourniquet review, surgical tourniquet, CAT® bleeding intervention procedures, bleeding physiology and complications, prehospital tourniquet use in recent conflicts, medical simulation fidelity, and a review of the value of animatronic movement during tourniquet simulation-based training. I then evaluate the effectiveness of animatronic movement during tourniquet training using the Advanced MATT in an experiment using Army first responders. The control group experienced no movement while the experimental group experienced movement when applying a tourniquet during the lab-training. Each group then alternately experienced Advanced MATT movement during an immersive scenario along with fog, strobe lights, and battle sounds. It was hypothesized that 1) In the immersive scenario, the experimental groups (i.e., those who were trained on a moving simulator) would have a faster reaction time as compared to those participants who did not receive training on the moving Advanced MATT simulator; 2) In the iv lab-based training, the experimental groups would have a slower reaction time; 3) In the immersive scenario, the experimental groups would have a faster tourniquet application time when subjected to movement while in the lab-based training, but the experimental groups would also have a slower tourniquet application time when initially subjected to movement in the laboratory-based training; finally, 4, 5, and 6) Participants who completed lab-based tourniquet training on the Advanced MATT simulation with animatronic movement would report higher perceived realism scores than participants who complete the training on a static version of the Advanced MATT and participants who completed a tourniquet training immersive scenario on the Advanced MATT simulation with movement would report higher perceived realism, presence, and self-efficacy scores than participants who complete the training on a static version of the Advanced MATT. The empirical results show a significant overall training effect of the Advanced MATT simulator (with or without movement). For reaction time and tourniquet application time, involving simulator movement was significant over varying scenarios. A small reduction in reaction and tourniquet application time on the battlefield may be extremely beneficial on the battlefield. Participants who received movement generally gave more positive reactions than those who did not received movement, although these results failed to reach statistical significance. Participants who received movement, followed by a scenario without movement rated the subjective ratings the lowest, suggestive of the lack of movement. Furthermore, despite the order movement was received, no large drops in performance occurred in any condition, indicating that negative training was avoide

Development and validation of a hybrid surgical simulator for ultrasound guided laparoscopic common bile duct exploration

This thesis investigates using 3D printing for developing a low-cost, quick, and simple fabrication method for the surgical simulation of the basic skills needed in a laparoscopic common bile duct exploration using ultrasound. This is achieved through a human-centred design methodology where each step of the development is guided by interactions or evaluations with the end users. The specifications are defined by using interviews to understand the needs of surgeons in a simulation practice and to characterise the experience of performing surgery, including the embodied knowledge of surgeons when they manipulate soft tissues. Using an action research methodology combining qualitative and quantitative evaluations in an iterative process, commonly used materials in simulation are thoroughly investigated to identify the most suitable synthetic materials for each type of soft tissue. The synthetic materials identified are silicones because of their tactile properties; moreover, two augmented reality techniques are implemented in addition to the physical model. The first one is style transfer, which aims to improve the appearance of the physical simulator when it is viewed through the laparoscopic camera. The style transfer algorithm used during this research can successfully modify the appearance of the simulator to replicate the diversity of real life. The second technique is marker tracking, which is used to simulate the laparoscopic ultrasound step by overlaying pre-recorded ultrasound images onto the physical model. This technique allows surgeons to practice reading laparoscopic ultrasound images and identifying key anatomical features during the surgery. Through consultations with the surgeons, the outcomes of this research are evaluated using face, content, and construct validations. Throughout this thesis, the research methods and results are explained and discussed to provide a basis for further research. These findings can be used as a framework for future development of surgical simulators