Biomedical subjects

Alessandro Faraci

Publications and source records attributed to Alessandro Faraci.

5 recordsLinked to original sources

PubMed2005

Soft tissue deformation using a nonlinear hierarchical finite element model with real-time online refinement.

Simulating soft tissue deformation in real-time is a requirement for realistically rendering the VR interaction between human organs and surgical tools. Finite Element Model (FEM) describes complex mechanical and physiological behaviour but it is computationally too demanding especially when a nonlinear model is to be implemented. For this reason, we introduce a multiresolution approach to FEM that only employs the region of the object under deformation to find the solution of the differential equations of motion. In order to increase the quality of the deformation, refinement of the original mesh is performed with the insertion of new surface nodes in real-time in the region of interaction. To guarantee the stability of the nonlinear model, the presence of flat tetrahedra (slivers) has to be avoided; therefore a sliver elimination technique has been implemented resulting in a more stable simulation.

Clinical Competence↗

PubMed2004

Soft tissue deformation using a Hierarchical Finite Element Model.

Simulating soft tissue deformation in real-time has become increasingly important in order to provide a realistic virtual environment for training surgical skills. Several methods have been proposed with the aim of rendering in real-time the mechanical and physiological behaviour of human organs, one of the most popular being Finite Element Method (FEM). In this paper we present a new approach to the solution of the FEM problem introducing the concept of parent and child mesh within the development of a hierarchical FEM. The online selection of the child mesh is presented with the purpose to adapt the mesh hierarchy in real-time. This permits further refinement of the child mesh increasing the detail of the deformation without slowing down the simulation and giving the possibility of integrating force feedback. The results presented demonstrate the application of our proposed framework using a desktop virtual reality (VR) system that incorporates stereo vision with integrated haptics co-location via a desktop Phantom force feedback device.

Connective Tissue↗

PubMed2004

Segmentation and generation of patient-specific 3D models of anatomy for surgical simulation.

Patient-specific simulation requires detailed 3D anatomical models. This paper describes how using optimised MRI sequences and clear segmentation criteria, together with adequate segmentation tools can produce high fidelity models able to reflect anatomical variability and allow realistic simulation of operative techniques and conditions.

England↗

PubMed2004

Validation of soft tissue properties in surgical simulation with haptic feedback.

Numerous experiments are being conducted to extract soft tissue values for their integration into VR surgical simulations with haptic feedback. Haptic feedback has been shown to be relevant in laparoscopic surgery, however to date no experiments have been conducted to test user sensitivity to changes in soft tissue values in surgical simulations, and how users perception of 'reality' differs from experimentally determined soft tissue values. In this study we conduct a series of experiments investigating haptic sensitivity, haptic differentiation and comparing experimental and empirical values.

Connective Tissue↗

PubMedDate not supplied

Online remeshing for soft tissue simulation in surgical training.

To graphically model and animate the realistic behavior of deformable tissue in surgical simulations, the authors' system adapts tetrahedra resolution by dynamically retessellating the mesh in and around the regions of interest. This technique overcomes limitations of previous methods that made it difficult to modify the mesh's topology online.

Computer Graphics↗