Intraoperative Computed Tomography and Finite Element Modelling for Multimodal Image Fusion in Brain Surgery

2019 ◽  
Vol 18 (5) ◽  
pp. 531-541 ◽  
Author(s):  
Marco Riva ◽  
Patrick Hiepe ◽  
Mona Frommert ◽  
Ignazio Divenuto ◽  
Lorenzo G Gay ◽  
...  
Keyword(s):  
Finite Element ◽  
Image Fusion ◽  
Qualitative Evaluation ◽  
Element Model ◽  
Fusion Algorithm ◽  
Registration Accuracy ◽  
Control Structures ◽  
Intraoperative Computed Tomography ◽  
Target Registration Error ◽  
And Control

Abstract BACKGROUND intraoperative computer tomography (iCT) and advanced image fusion algorithms could improve the management of brainshift and the navigation accuracy. OBJECTIVE To evaluate the performance of an iCT-based fusion algorithm using clinical data. METHODS Ten patients with brain tumors were enrolled; preoperative MRI was acquired. The iCT was applied at the end of microsurgical resection. Elastic image fusion of the preoperative MRI to iCT data was performed by deformable fusion employing a biomechanical simulation based on a finite element model. Fusion accuracy was evaluated: the target registration error (TRE, mm) was measured for rigid and elastic fusion (Rf and Ef) and anatomical landmark pairs were divided into test and control structures according to distinct involvement by the brainshift. Intraoperative points describing the stereotactic position of the brain were also acquired and a qualitative evaluation of the adaptive morphing of the preoperative MRI was performed by 5 observers. RESULTS The mean TRE for control and test structures with Rf was 1.81 ± 1.52 and 5.53 ± 2.46 mm, respectively. No significant change was observed applying Ef to control structures; the test structures showed reduced TRE values of 3.34 ± 2.10 mm after Ef (P < .001). A 32% average gain (range 9%-54%) in accuracy of image registration was recorded. The morphed MRI showed robust matching with iCT scans and intraoperative stereotactic points. CONCLUSIONS The evaluated method increased the registration accuracy of preoperative MRI and iCT data. The iCT-based non-linear morphing of the preoperative MRI can potentially enhance the consistency of neuronavigation intraoperatively.

Additional Damping Conditions Analysis and Calculation for Exciting Force and External Load

2013 ◽  
Vol 579-580 ◽  
pp. 507-511
Author(s):  
Yi Xiang Liu ◽  
Yong Mei Wang
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Structure Design ◽  
Exciting Force ◽  
Reduction Gear ◽  
Solid Model ◽  
Gear Noise ◽  
Force Reduction ◽  
And Control ◽  
The Impact

This paper firstly starting mechanism of vibration and noise from gear, gear noise mechanism is explained, and analyze the factors and the impact of noise on the gear reducer. Secondly, the establishment of a complete solid model of gear reducer and reducer model for finite element model, the reduction gear box gear reducer of modal analysis and finite element modal calculation, and points out the dynamic analysis of structure, size and weight factor is proportional to the reciprocal of the modal frequencies of each mode is the with the frequency is low, that is, the greater the weight. Once again, the main measure of load and control of gear noise of gear is analyzed, including the calculation, for exciting force reduction gear reducer gear load computation. The analysis and calculation are the theoretical basis of gear structure design and its performance evaluation.

Increasing bending angle in thick-walled pipes with wide heating

2019 ◽  
Vol 20 (6) ◽  
pp. 616
Author(s):  
Seyed Ehsan Chavoshi ◽  
Seyed Ebrahim Moussavi Torshizi
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Element Model ◽  
Bending Angle ◽  
Circular Zone ◽  
Simultaneous Control ◽  
Simultaneous Heating ◽  
And Control ◽  
Small Deformations ◽  
The Finite Element Model

The spot heating of a metal part leads to many small deformations. The applications of this method are straightening the bridge parts, turbo-machinery shafts, and so forth. The movement of the heat source on a given path (line heating) leads to an increase in the deformation and the possibility of creating complex bends. However, it is complicated to predict and control the path and velocity of the heat source as well as determining the heat intensity. In the pipes, this method requires simultaneous control over the two torches on both sides of the pipe. The present study aims at investigating the mechanism of deformation and increasing the bending angle in thick pipes by means of a simple heating method. At first, the maximum bending in heating a large circular zone (entitled “wide heating”) is obtained by simulating the process using finite element method and optimizing it applying the genetic aggregation algorithm. Then, a new method for simultaneous heating within two zones is introduced. The interaction between two zones leads to the development of the shortening mechanism in the pipe wall and a significant increase in the bending angle. In this method, there is no need to move the torch where the temperature is controlled more accurately. To evaluate the finite element model, several pipe heating tests are performed with their results being agreed well with the simulation results.

scholarly journals Study on the stress of micro-S-shaped folding cantilever

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092486 ◽  
Author(s):  
Shuangjie Liu ◽  
Yongping Hao ◽  
Xiannan Zou
Keyword(s):  
Finite Element ◽  
Theoretical Model ◽  
Complex Structure ◽  
Element Model ◽  
Theoretical Formula ◽  
Yield Limit ◽  
Force Analysis ◽  
Micro Cantilever ◽  
And Control ◽  
The Finite Element Model

Micro-cantilever has shown wide application prospect in the field of micro-sensors, actuators, gyroscope, and so on. There are abundant research studies on simple cantilever beam models, but there are few on S-shaped folding cantilever with complex structure, although it is widely used. In order to study the deformation failure of S-shaped folding cantilever, the force analysis of S-shaped folding cantilever was carried out in this article, and the stress values of different positions under the external load of the cantilever were deduced. The finite element model about S-shaped folding cantilever was built based on software ANSYS. The theoretical calculation was compared with the finite element calculation, and the results showed that the max stress is 681 MPa based on the derived theoretical formula, the max stress is 673 MPa based on the ANSYS, the error is 1.18%, which can prove formula is accurate. To further validate the stress predicted by the mathematical modeling, a micro-force testing platform was built to test the cantilever. Since the stress value cannot be measured directly in the test, the force corresponding to the stress was taken as standard and compared it with the simulation. The tested external force was corresponding the yield limit. The results showed that the experimental force was 0.06462 N before the plastic deformation occurred, the theoretical outcome was 0.065231 N corresponding the yield limit, the error was 0.94%. Both simulation and experimental results depict that the theoretical model is effective for predicting the stress of the S-shaped folded cantilever. The theoretical model helps to enhance the efficiency, and improve the performance, predictability, and control of the S-shaped folding cantilever.

Understanding and modelling the torsional stiffness of harmonic drives through finite-element method

2009 ◽  
Vol 223 (2) ◽  
pp. 515-524 ◽  
Author(s):  
F-E Rhéaume ◽  
H Champliaud ◽  
Z Liu
Keyword(s):  
Finite Element ◽  
Numerical Model ◽  
Element Model ◽  
Torsional Stiffness ◽  
Geometrical Parameters ◽  
Mechanical Products ◽  
Torque Capacity ◽  
High Reduction ◽  
And Control ◽  
Crucial Characteristic

Torsional stiffness or rigidity is a crucial characteristic in the design of transmission devices, including harmonic drives (HDs). Among the various design aspects constituting a reduction mechanism in robotic systems, torsional stiffness is an important factor for positioning accuracy and control issues. One of the major advantages of HDs is their capacity to present a high reduction ratio while maintaining a small hardware size. However, manufacturing these drives remains a complex and costly process due to the high precision of its machined components; as a result, the use of such drives is still limited only to high-end mechanical products and technologies. Given these costs, numerical analysis becomes an effective alternative for obtaining valuable data through simulations, without the need for prototypes. This article presents a finite-element model to reproduce the behaviour of the torsional stiffness of an HD. The numerical model allows an evaluation of the effects of various geometrical parameters on the torsional stiffness of the HD. The numerical model of the HD can be used for optimization purposes, i.e. to develop an HD with a high torque capacity combined with a high-rated lifespan.

Simulation and Control of Two Side Direction Burr

2011 ◽  
Vol 143-144 ◽  
pp. 428-432 ◽  
Author(s):  
Hai Jun Qu ◽  
J.H. Yang ◽  
Gui Cheng Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Formation Mechanism ◽  
Element Model ◽  
Burr Formation ◽  
Analysis Method ◽  
Physical Insight ◽  
Side Face ◽  
And Control ◽  
Insight Into

A finite element model was developed for simulation of two side direction burr formation process. Based on strain distribution, a two side burr formation mechanism was proposed. Burr form and burr size of simulation are close to that's of experiment. Finite element model generated here provided a numerical analysis method to solve the prediction of burr and chip formation and physical insight into the fundamental burr formation mechanism. The stain in two side direction of material near the side face decides the shape and the size of two side direction. Multi-workpieces are machined at the same time with side face closely by each others can control the formation of two side direction strain and two side direction burr.

On Some Information Metrics of Intelligent Material Systems

2008 ◽  
Author(s):  
Fabio P. Bonsignorio
Keyword(s):  
Finite Element ◽  
Statistical Physics ◽  
Computational Models ◽  
Element Model ◽  
Physical Structure ◽  
Material System ◽  
Intelligent Material ◽  
Improved Performance ◽  
And Control ◽  
Information Metrics

In this paper it is proposed a theoretical model of an ‘intelligent material’ system. An ‘intelligent material’ body is seen as a flexible body capable to manage energy, deformations and information. In any finite element dynamical, material and information processing properties are coexisting and interacting. On the basis of some Shannon and Kolgomorov theory and network statistical physics relations, it is shown how such a material is actually able to store and process information in itself physical structure. Some relations linking the dynamical characteristics to the information metrics are shown. A finite element model for intelligent materials is outlined. The aim of this approach is, on one side, to explain why the payload ratio of, for example, an human arm is much higher than that of a (current) robotic arm, on the other end, to suggest that deeper relations between material dynamics computational models, information and control theory could help design new artifacts with new improved performance, closer to what we can see in natural biological examples.

scholarly journals Navigated 3D Ultrasound in Brain Metastasis Surgery: Analyzing the Differences in Object Appearances in Ultrasound and Magnetic Resonance Imaging

2020 ◽  
Vol 10 (21) ◽  
pp. 7798
Author(s):  
Benjamin Saß ◽  
Barbara Carl ◽  
Mirza Pojskic ◽  
Christopher Nimsky ◽  
Miriam Bopp
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Brain Metastasis ◽  
3D Ultrasound ◽  
Resonance Imaging ◽  
Registration Accuracy ◽  
Registration Method ◽  
Intraoperative Computed Tomography ◽  
Target Registration Error ◽  
Dural Opening

Background: Implementation of intraoperative 3D ultrasound (i3D US) into modern neuronavigational systems offers the possibility of live imaging and subsequent imaging updates. However, different modalities, image acquisition strategies, and timing of imaging influence object appearances. We analyzed the differences in object appearances in ultrasound (US) and magnetic resonance imaging (MRI) in 35 cases of brain metastasis, which were operated in a multimodal navigational setup after intraoperative computed tomography based (iCT) registration. Method: Registration accuracy was determined using the target registration error (TRE). Lesions segmented in preoperative magnetic resonance imaging (preMRI) and i3D US were compared focusing on object size, location, and similarity. Results: The mean and standard deviation (SD) of the TRE was 0.84 ± 0.36 mm. Objects were similar in size (mean ± SD in preMRI: 13.6 ± 16.0 cm3 vs. i3D US: 13.5 ± 16.0 cm3). The Dice coefficient was 0.68 ± 0.22 (mean ± SD), the Hausdorff distance 8.1 ± 2.9 mm (mean ± SD), and the Euclidean distance of the centers of gravity 3.7 ± 2.5 mm (mean ± SD). Conclusion: i3D US clearly delineates tumor boundaries and allows live updating of imaging for compensation of brain shift, which can already be identified to a significant amount before dural opening.

Test Research on Loading Safety and Space Finite Element Analysis of Existing Buildings Reconstruction

2012 ◽  
Vol 204-208 ◽  
pp. 3580-3583
Author(s):  
Zhong Qiang Wang ◽  
Tao Ouyang
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Visual Inspection ◽  
Flexural Rigidity ◽  
Element Model ◽  
Existing Buildings ◽  
Element Analysis ◽  
Main Structure ◽  
Finite Element Software ◽  
And Control

Existing buildings continue to use, maintenance or reconstruction, are required to appraisal and evaluation the security of structure[3], to ensure the in-service safety. Combing with a practical example of Better-life Commercial Chain Share Co,. Ltd in Changsha Red Star shop add billboard, have a visual inspection to the billboard support structure, investigate the use of the current situation and analyze the type of disease; using the finite element software MIDAS to establish finite element model of billboard and the main structure of its support, have a large number of numerical simulation; the results showed that the billboard design is reasonable, the flexural rigidity and carrying capacity of the main structure is acceptable, but the disease is more, endanger the use of safe, should carry out prevention and control processing.

3-D FE Simulation and Analysis on Radial-Axial Large Ring Rolling

2007 ◽  
Vol 561-565 ◽  
pp. 1903-1906 ◽  
Author(s):  
Li Bo Pan ◽  
Lin Hua ◽  
Jian Lan
Keyword(s):  
Finite Element ◽  
Fe Simulation ◽  
Element Model ◽  
Rolling Process ◽  
Ring Rolling ◽  
Explicit Finite Element ◽  
Finite Element Technology ◽  
Axial Ring ◽  
Guide Roller ◽  
And Control

An effective method was proposed to simulate and control the motion track of guide roller during radial-axial ring rolling in FE simulation. The 3-D finite element model was constructed according to the principle and feature of rolling technology. The rolling process was simulated and analyzed by using dynamic explicit finite element technology. The different rolling processes with different technology parameter were simulated. The width spreads and rolling forces under different parameters are compared and analyzed. The results indicated that high quality ring product could be obtained when rational parameters in radial and axial were assigned.

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