Guidewire Model Research Articles

Design and development of a personalized virtual reality-based training system for vascular intervention surgery

Background and objectivesVirtual training has emerged as an exceptionally effective approach for training healthcare practitioners in the field of vascular intervention surgery. By providing a simulated environment and blood vessel model that enables repeated practice, virtual training facilitates the acquisition of surgical skills in a safe and efficient manner for trainees. However, the current state of research in this area is characterized by limitations in the fidelity of blood vessel and guidewire models, which restricts the effectiveness of training. Additionally, existing approaches lack the necessary real-time responsiveness and precision, while the blood vessel models suffer from incompleteness and a lack of scientific rigor. MethodsTo address these challenges, this paper integrates position-based dynamics (PBD) and its extensions, shape matching, and Cosserat elastic rods. By combining these approaches within a unified particle framework, accurate and realistic deformation simulation of personalized blood vessel and guidewire models is achieved, thereby enhancing the training experience. Furthermore, a multi-level progressive continuous collision detection method, leveraging spatial hashing, is proposed to improve the accuracy and efficiency of collision detection. ResultsOur proposed blood vessel model demonstrated acceptable performance with the reduced deformation simulation response times of 7 ms, improving the real-time capability at least of 43.75 %. Experimental validation confirmed that the guidewire model proposed in this paper can dynamically adjust the density of its elastic rods to alter the degree of bending and torsion. It also exhibited a deformation process comparable to that of real guidewires, with an average response time of 6 ms. In the interaction of blood vessel and guidewire models, the simulator blood vessel model used for coronary vascular intervention training exhibited an average response time of 15.42 ms, with a frame rate of approximately 64 FPS. ConclusionsThe method presented in this paper achieves deformation simulation of both vascular and guidewire models, demonstrating sufficient real-time performance and accuracy. The interaction efficiency between vascular and guidewire models is enhanced through the unified simulation framework and collision detection. Furthermore, it can be integrated with virtual training scenarios within the system, making it suitable for developing more advanced vascular interventional surgery training systems.

Effect of guidewire on the accuracy of trans-stenotic pressure measurement—A computational study

Accurate measurement of trans-stenotic pressure drop is vital for risk stratification in coronary artery disease. Currently, in vivo pressure measurement relies mostly on a pressure guidewire inserted into the artery, which inevitably alters local hemodynamics. To precisely assess the impact of guidewire insertion on the accuracy of pressure measurement, this study conducts numerical simulations with both an idealized straight-tube model and a patient-specific model. Results with and without a guidewire model are compared and analyzed. Results from the idealized model reveal that the insertion of a guidewire shifts velocity distribution, increases resistance, and amplifies the pressure drop across the stenosis. The patient-specific model also demonstrates that the guidewire causes non-negligible flow redistribution among the arterial branches, but the influence on pressure drop remains mostly localized. An analytical model for trans-stenotic pressure drop that takes the guidewire into consideration is also proposed and validated against the 3D simulation results. It is observed that the maximum relative error is around 3.0% in the patient-specific model, indicating the effectiveness of the analytical model in physiologically accurate settings. The proposed model can be used to align computed tomography-derived fractional flow reserve values with clinically recognized FFR standards established through guidewire measurements.

Special Issue: Nonlinear and Computational Dynamics in Biomedical Applications

Special Issue: Nonlinear and Computational Dynamics in Biomedical Applications

Investigation of Guidewire Deformation in Blood Vessels Based on an SQP Algorithm

This paper proposes a solution to the simulated deformation of guidewires when they come in contact with the blood vessel in an interventional surgery simulation training system. Starting from the principle of minimum energy, the guidewire is evenly dispersed into a rigid light bar articulation model. A sequential quadratic programming (SQP) algorithm is used to nonlinearly optimize the deflection angle of each light bar. When the elastic potential energy of the guidewire reaches a minimum, we can get the guidewire deformation we want to solve. The method proposed in this paper avoids necessity of delving into contact deformation caused by the contact force between the guidewire and the blood vessel wall, while solving the problem of the deformation of the guidewire due to the pose of the contact points. We use an ABAQUS (finite element software) simulation to verify that this solution has a theoretical simulation accuracy of 5.11%, and the designed experiments prove that the actual simulation accuracy is about 11%. Moreover, we also simulated the bending stress state of the guidewire by using the deflection angle of each bar. In addition, in order to achieve the most suitable simulation results, we discuss the discrete density of the guidewire model from the perspective of algorithm time consumption and simulation accuracy.

Higher-Order Approximation to the Guidewire Model Used in Simulators of Cardiac Catheterization and Multiple Segment Relaxations

Abstract Cardiac catheterism is important because it offers many advantages in comparison to open surgery, for example, fewer injuries, lower risk of infections, and shorter recovery times. Simulators play a fundamental role in training packages, and virtual learning environments are less stressful. Moreover, they can also be used in certification boards and in performance assessments. A realistic and interactive simulator must be fast. In this work, the physical model of the guidewire used in catheter simulations has been improved. In particular, we determined a simple analytic expression to calculate the direction of a guidewire segment, which minimizes the total energy. The surface energy resulting from the guidewire--artery interaction and the bending energy of the guidewire is approximated up to the second order, which gives rise to interactions between segments. Furthermore, the multiple segment relaxations are introduced, enhancing the convergence especially at the beginning of the relaxation cycle. The formulas are written in matrix form of dimension 4M×4M, where M represents the number of segments varied in the update step. The method results in a more stable static solution.

Blood flow-induced physically based guidewire simulation for vascular intervention training.

A realistic guidewire behavior simulation is a vital component of a virtual vascular intervention system. Such systems are a safe, low-cost means of establishing a training environment to help inexperienced surgeons develop their intervention skills. Previous attempts to simulate the complex movement of a guidewire inside blood vessels have rarely considered the influence of blood flow. In this paper, we address this problem by integrating blood flow analysis and propose a novel guidewire simulation model. The blood flow distribution inside the arterial vasculature was computed by separating the vascular model into discrete cylindrical vessels and modeling the flow in each vessel according to Poiseuille Law. The blood flow computation was then integrated into a robust Kirchhoff elastic model. With hardware acceleration, the guidewire simulation can be run in real time. To evaluate the simulation, an experimental environment with a 3D-printed vascular phantom and an electromagnetic tracking system was set up, with clinically used guidewire sensors applied to trace its motion as the standard for comparison. The virtual guidewire motion trace was assessed by comparing it to the comparison standard. The root-mean-square (RMS) value of the newly proposed guidewire model was 2.14mm±1.24mm, lower than the value of 4.81mm±3.80mm for the previous Kirchhoff model, while maintaining a computation speed of at least 30fps. The experimental results revealed that the blood flow-induced model exhibits better performance and physical credibility with a lower and more stable RMS error than the previous Kirchhoff model.

Fast and stable guidewire simulator for minimally invasive vascular surgery.

In recent years, minimally invasive vascular surgery is widely applied in treatment of cardiovascular diseases, and the manipulation of the guidewire is the essential skill for this surgery. Lots of time and money have to be taken to achieve the skill. In this paper, we present a multithreading guidewire simulator which can help the apprentice to gain the skill and modeling the guidewire is the core technique of the simulator. The guidewire is modeled by a fast and stable method based on the Cosserat theory of elastic rods. The method describes the behavior of the guidewire with the Lagrange equations of motion and it uses the penalty method to maintain constraints. We further propose a simplified solving procedure for the guidewire model. Finally, some experiments are conducted to evaluate the effectiveness of this model.

Numerical analysis and experimental observation of guidewire motion in a blood vessel model

We have developed a computer-based system to simulate a guidewire in blood vessels for surgical planning, intra-operative assistance, and to facilitate the design of new guidewires. In this study, we compared simulation results with experimental results for validation of the simulation system. First, we inserted a commercial guidewire into a poly (vinyl alcohol) hydrogel blood vessel model using a two-axis automatic stage and measured the position of the guidewire tip and the contact force between the guidewire and the vessel. The experimental apparatus can be used not only for the validation of numerical analyses, but also as a simulation system. Second, similarly to the experiment, the motion of the guidewire in the blood vessel model was calculated when the proximal part of the guidewire model was pushed and twisted. The model of the guidewire is constructed with viscoelastic springs and segments, and the proximal part of the guidewire model is constrained by the fixed catheter model. Collisions between the guidewire and the vessel are calculated, and the contact forces are determined according to the stiffness of the vessel wall. The same tendency was seen in the trajectories and the contact force of both the experimental and simulated guidewire tips.

Numerical Analysis of Palpation in vivo Using Tactile Sensor Composed of Organic Ferroelectrics

Tactile sensors using organic ferroelectrics are promising from the viewpoint of palpation because poly(vinylidene fluoride) [PVDF] tactile sensors have already been developed to evaluate living tissue. Moreover, vinylidene fluoride (VDF) oligomer is a new substance with a smaller number of VDF units than PVDF. As the piezoelectric coefficient of VDF oligomer is great and its film is thin and uniform, it is suitable for preparation of thinner film tactile sensor. On the other hand, in our previous study, we also developed a computer-based surgical simulator to simulate a catheter and guidewire in blood vessels of the brain. In this study, we investigated the palpation in vivo by the tactile sensor composed of organic ferroelectrics using our catheter/guidewire simulator. Using this simulator, the output of the sensor attached on the guidewire tip was calculated when the proximal part of the guidewire model was pushed and pulled. We used the blood vessel model where the friction coefficient or the stiffness was changed partially assuming that these changes occur by a disease. When the friction coefficient between the guidewire and the vessel was large, the sensor outputs became large. When the stiffness of the vessel was small, the sensor outputs became small.

Simulation of endovascular guidewire behaviour and experimental validation

Guidewire manipulation is a core skill in endovascular interventional radiology procedures. Simulation-based training offers a valuable alternative for mastering these skills, but requires a faithful replication of complex guidewire behaviour inside the vasculature. This paper presents the integration of real flexural modulus (FM) measurements into our guidewire model that mimics the flexibility of standard guidewires. The variation of FM along the length of each wire was determined for seven commonly used guidewires using a three-point bending test for the main body and a two-point bending test for the flexible end. Guidewire FM values were then attributed to seven different models, each formed by a series of particles connected by links of variable FM and replicating the flexible end shape. The FM integration was done through a trial and error process matching real FM to virtual bending coefficient. This mass-spring representation captures the required range of behaviour and enables accurate deformation within virtual vasculature.

Development of Computer-Based Simulator for Catheter Navigation in Blood Vessels (2nd Report, Evaluation of Torquability of Guidewire)

We have developed catheter simulation system in blood vessels for surgical planning and intraoperative assistance. In this study, we evaluated the torquability of the guidewire model for the simulation system. The model of the guidewire is constructed with viscoelastic springs and segments as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness and friction of the vessel wall. Using these models, the trajectory of the guidewire tip was calculated when the proximal part of the guidewire model was twisted at a constant speed. When the friction coefficient between the guidewire and the vessel is large, the guidewire tip vibrates. When the guidewire is twisted, there is a lag before the guidewire tip starts rotating and friction obstructs this rotation. Besides the friction coefficient, the shape of the blood vessel also affects the motion of the guidewire tip. When the guidewire becomes stiffer, the torquability of guidewire tip increases. This simulator would be useful for the analysis of the structure of the guidewire and may help guide the design of new guidewire.