Ten CAD Challenges

Kasik, David J.; Buxton, William; Ferguson, D. R.

doi:10.1109/mcg.2005.48

Cited by 47 publications

(24 citation statements)

References 3 publications

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“…Anatomical three-dimensional shape editing is one of the major challenges of the pre-surgical planning paradigm as cardiovascular geometries involve non-uniform vessel caliber and curvature, and conduits require complex multiple inlet–outlet geometries, which cannot be easily modified by combinations of mathematically simple binary operations or shape primitives offered by state-of-art CAD software 19. We introduced the first generation ‘interactive’ surgical planning tool, SURGEM,36 which incorporates a two-hand haptic interface to freely deform, bend and position 3D surgical baffles real-time.…”

Section: Introductionmentioning

confidence: 99%

Computer-Aided Patient-Specific Coronary Artery Graft Design Improvements Using CFD Coupled Shape Optimizer

Dur

Coskun

et al. 2010

Cardiovasc Eng Tech

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This study aims to (i) demonstrate the efficacy of a new surgical planning framework for complex cardiovascular reconstructions, (ii) develop a computational fluid dynamics (CFD) coupled multi-dimensional shape optimization method to aid patient-specific coronary artery by-pass graft (CABG) design and, (iii) compare the hemodynamic efficiency of the sequential CABG, i.e., raising a daughter parallel branch from the parent CABG in patient-specific 3D settings. Hemodynamic efficiency of patient-specific complete revascularization scenarios for right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX) bypasses were investigated in comparison to the stenosis condition. Multivariate 2D constraint optimization was applied on the left internal mammary artery (LIMA) graft, which was parameterized based on actual surgical settings extracted from 2D CT slices. The objective function was set to minimize the local variation of wall shear stress (WSS) and other hemodynamic indices (energy dissipation, flow deviation angle, average WSS, and vorticity) that correlate with performance of the graft and risk of re-stenosis at the anastomosis zone. Once the optimized 2D graft shape was obtained, it was translated to 3D using an in-house “sketch-based” interactive anatomical editing tool. The final graft design was evaluated using an experimentally validated second-order non-Newtonian CFD solver incorporating resistance based outlet boundary conditions. 3D patient-specific simulations for the healthy coronary anatomy produced realistic coronary flows. All revascularization techniques restored coronary perfusions to the healthy baseline. Multi-scale evaluation of the optimized LIMA graft enabled significant wall shear stress gradient (WSSG) relief (~34%). In comparison to original LIMA graft, sequential graft also lowered the WSSG by 15% proximal to LAD and diagonal bifurcation. The proposed sketch-based surgical planning paradigm evaluated the selected coronary bypass surgery procedures based on acute hemodynamic readjustments of aorta-CA flow. This methodology may provide a rational to aid surgical decision making in time-critical, patient-specific CA bypass operations before in vivo execution.

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Section: Introductionmentioning

confidence: 99%

Computer-Aided Patient-Specific Coronary Artery Graft Design Improvements Using CFD Coupled Shape Optimizer

Dur

Coskun

et al. 2010

Cardiovasc Eng Tech

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“…While these operations were conceptually and geometrically simple (uniform dilatation and linear IVC translation), realizing these in the computer medium with the state-of-the art commercial CAD systems, introduced enormous difficulties due to the complex, highly variable morphologies [26]. Unlike the perfect and uniform geometrical shapes designed in many traditional engineering CAD and computer-aided manufacturing applications, vascular anatomies are patientspecific and cannot be easily constructed as combinations of a small number of mathematically simple shape primitives or created by a sequence of digital counterparts of manufacturing operations [22]. Recent polyhedral modeling paradigms [9,38] and related commercial tools that are developed particularly for inverse engineering design [81] and animation [82] can address the geometric complexity and offer considerable help in patient-specific applications.…”

Section: Introductionmentioning

confidence: 99%

Patient-specific surgical planning and hemodynamic computational fluid dynamics optimization through free-form haptic anatomy editing tool (SURGEM)

Pekkan

Whited

Kanter

et al. 2008

Med Biol Eng Comput

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The first version of an anatomy editing/surgical planning tool (SURGEM) targeting anatomical complexity and patient-specific computational fluid dynamics (CFD) analysis is presented. Novel three-dimensional (3D) shape editing concepts and human-shape interaction technologies have been integrated to facilitate interactive surgical morphology alterations, grid generation and CFD analysis. In order to implement "manual hemodynamic optimization" at the surgery planning phase for patients with congenital heart defects, these tools are applied to design and evaluate possible modifications of patient-specific anatomies. In this context, anatomies involve complex geometric topologies and tortuous 3D blood flow pathways with multiple inlets and outlets. These tools make it possible to freely deform the lumen surface and to bend and position baffles through real-time, direct manipulation of the 3D models with both hands, thus eliminating the tedious and time-consuming phase of entering the desired geometry using traditional computer-aided design (CAD) systems. The 3D models of the modified anatomies are seamlessly exported and meshed for patient-specific CFD analysis. Free-formed anatomical modifications are quantified using an in-house skeletization based cross-sectional geometry analysis tool. Hemodynamic performance of the systematically modified anatomies is compared with the original anatomy using CFD. CFD results showed the relative importance of the various surgically created features such as pouch size, vena cave to pulmonary artery (PA) flare and PA stenosis. An interactive surgical-patch size estimator is also introduced. The combined design/analysis cycle time is used for comparing and optimizing surgical plans and improvements are tabulated. The reduced cost of patient-specific shape design and analysis process, made it possible to envision large clinical studies to assess the validity of predictive patient-specific CFD simulations. In this paper, model anatomical design studies are performed on a total of eight different complex patient specific anatomies. Using SURGEM, more than 30 new anatomical designs (or candidate configurations) are created, and the corresponding user times presented. CFD performances for eight of these candidate configurations are also presented.

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“…Multi-objective optimization (MOO) methods basically search through large design spaces guided by objective functions (Kasik, Buxton, & Ferguson, 2005). The generation of these search spaces in the design field relies on PM by continuously updating the inputs and improving the model, or automatically producing an entire set of all possible alternatives within the range of the parameters.…”

Section: Multi-objective Optimizationmentioning

confidence: 99%

From Parametric to Meta Modeling in Design

Bernal¹

2016

Blucher Design Proceedings

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This study introduces the Meta-Modeling process adopted from the Model Based System Engineering field (MBSE) to explore an approach for the generation of design alternatives beyond the restrictions of the Parametric Models that mainly produce geometric variations and have limitations in terms of topological transformations during the exploratory design tasks. The Meta-Model is the model of attributes and relationships among objects of a particular domain. It describes objects and concepts in abstract terms independent from the complexity of the geometric models and provides mapping mechanisms that facilitate the interfacing with parametric parts. The flexibility of these computerinterpretable and human-readable models can contribute to creatively manipulate the design knowledge embedded in parametric models.

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Ten CAD Challenges

Cited by 47 publications

References 3 publications

Computer-Aided Patient-Specific Coronary Artery Graft Design Improvements Using CFD Coupled Shape Optimizer

Computer-Aided Patient-Specific Coronary Artery Graft Design Improvements Using CFD Coupled Shape Optimizer

Patient-specific surgical planning and hemodynamic computational fluid dynamics optimization through free-form haptic anatomy editing tool (SURGEM)

From Parametric to Meta Modeling in Design

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