scholarly journals Application of a three-dimensional virtual model to study the effect of fluoroscopic angle on infra-acetabular corridor parameters and screw insertion rates

2021 ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Reference Plane ◽  
Virtual Model ◽  
Screw Insertion ◽  
Pelvic Inlet ◽  
Line Angle ◽  
The Mean ◽  
Type Of Fracture ◽  
Tomography Data

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusions The traditional 45° pelvic inlet radiograph is not suitable as the fluoroscopic angle for IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.

scholarly journals Application of a three-dimensional virtual model to study the effect of fluoroscopic angle on infra-acetabular corridor parameters and screw insertion rates

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nengfeng Ma ◽  
Xufeng Hu ◽  
Zhoushan Tao ◽  
Min Yang
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Reference Plane ◽  
Virtual Model ◽  
Screw Insertion ◽  
Pelvic Inlet ◽  
Line Angle ◽  
The Mean ◽  
Type Of Fracture ◽  
Tomography Data

Abstract Purpose To use three-dimensional (3D) virtual models to study how the parameters and insertion rates of the infra-acetabular corridor (IAC) change under different fluoroscopic angles. Methods The pelvis computed tomography data of 187 patients are imported into Mimics software in DICOM format to generate a 3D model. The anterior pelvis plane is used as the reference plane to measure the diameter of the optimum IAC when the pelvis model is tilted forward by 5°, 15°, 25°, 35° and 45°. The diameter of at least 3.5 mm is defined as the cutoff for placing a 3.5 mm screw, the rate of infra-acetabular screw (IAS) insertion is calculated, and the mean length of the IAC and the mean tilt of the corridor axis in relation to the sagittal midline plane (SMP) are measured. Results The similar diameters of the IAC can be found under fluoroscopy at 5°–35°, with the largest diameter of 4.08 ± 1.84 mm and the highest screw insertion rate of 60.42% at 15° and 25°, whereas the diameter and insertion rate are lowest at 45°. The corridor length increases with increasing fluoroscopic angle, and the angle of the corridor axis to the SMP decreases gradually. Conclusion The conventional fluoroscopic angle of the pelvic inlet is not suitable for the IAS insertion. The parameters of the IAC vary according to a certain rule under different fluoroscopic angles, so a surgeon can select the appropriate fluoroscopic angle in accordance with the type of fracture and the fracture line angle.

scholarly journals Creación de implantes 3D en procesos de conservación y restauración de vidrio arqueológico

2017 ◽  
Vol 8 (16) ◽  
pp. 103 ◽  
Author(s):  
Carmen Díaz-Marín ◽  
Elvira Aura-Castro
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Virtual Model ◽  
Restricted Area ◽  
Non Invasive ◽  
3D Data ◽  
Invasive Method ◽  
Glass Bowl ◽  
Butadiene Styrene

This article describes the restoration of a glass bowl from the 16th-17thcentury by creating its three-dimensional (3D)model. The final purpose is to work with this model in order to avoid damaging situations that are associated with the manipulation of fragile objects. The gap areas, those corresponding to the missing fragments not found in the excavation, were carried out by constructing digital implants. A restricted area of the 3D model has been duplicated in order to accommodate it to confined intervals of the gap. The final implants were printed with acrylonitrile butadiene styrene (ABS) filament. These implants replace the lost areas and give stability back to the item by recovering the original morphology. The result can be compared with the outcome obtained by a traditional process, but differs due to the fact that requires minimum manipulation of the item, so it can contribute to preserve and safeguard the restored object. This is a non-invasive method which is offered as an alternative treatment, where the archaeological object is replaced by its virtual model in the steps of the process after 3D data acquisition. Significant differences have not been found in the 3D printing results obtained with the two types of filaments tested (white and clear).

scholarly journals Application of 3D Computed Tomography Reconstruction Images to Assess the Thickness and Dimensions of the Posterior Palatal Seal Area

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Soeun Lim ◽  
Seoung-Jin Hong ◽  
Joo-Young Ohe ◽  
Janghyun Paek
Keyword(s):  
Computed Tomography ◽  
3D Model ◽  
Three Dimensional ◽  
Ct Images ◽  
Anterior Border ◽  
Lateral Direction ◽  
Mean Dimension ◽  
The Mean ◽  
The Right ◽  
Palatal Mucosa

Few studies have been reported on the scientific measurements of the thickness and dimensions of the posterior palatal seal (PPS) area. The purpose of this study is to measure and analyze the thickness of palatal mucosa by using a three-dimensional (3D) model reconstructed with computed tomography (CT) images and to present objective values by identifying the PPS area. The CT images were reconstructed as a 3D model by separating the maxillary palate mucosa and teeth. Each reconstructed model was analyzed and the thickness was measured at 93 crossing points of each divided plane. The dimension of the PPS area was measured and the right and left dimensions of the PPS area were compared. The thickness of the palatal mucosa was thicker toward the posterior area. The thickness increased in the lateral direction and decreased again. In the PPS area, the mean dimension between the rearmost of anterior border and the most posterior line was 2.19 mm and the mean dimension between the forefront of anterior border and the most posterior line was 5.19 mm in the right side and 5.16 mm in the left side. The mean dimension from the center of the palate to the right most forward point was 6.85 mm, and the left was 7.36 mm. The new measurement method of palatal mucosal thickness is noninvasive, accurate, and easy to store and study, so it can be used effectively in planning and manufacturing the maxillary complete denture in the digital workflows.

3D Model Based Process in Automotive Industry

2018 ◽  
Vol 880 ◽  
pp. 151-156
Author(s):  
George Gherghina ◽  
Dragos Tutunea ◽  
Alexandru Dima ◽  
Dragos Laurentiu Popa
Keyword(s):  
Automotive Industry ◽  
3D Model ◽  
Three Dimensional ◽  
Virtual Model ◽  
3D Cad ◽  
Virtual Engineering ◽  
Software Packages ◽  
Development Processes ◽  
3D Software ◽  
2D Sketch

The three dimensional design of modern auto vehicle through advanced virtual engineering methods is used from early development processes. From over 10 years automotive manufacturers’ have used 3D-CAD software packages following conventional development strategies of the product. These tools offer the possibility to design components through digital mock-up processes reducing time and errors in production. In this paper we evaluate the evolution of 3D-CAD based development processes based on geometry generation, conceptual design and simulations tools. The DMU method allows importing the 2D sketch in 3D software then creates a virtual model which can be optimized and analyzed.

scholarly journals Augmented reality technology for auricular reconstruction in the treatment of microtia

2020 ◽  
Vol 9 (2) ◽  
pp. 78-82
Author(s):  
Аndrey I. Yaremenko ◽  
Anna V. Lysenko ◽  
Elizaveta A. Ivanova ◽  
Oleg V. Galibin
Keyword(s):  
Computer Simulation ◽  
Augmented Reality ◽  
Computer Technology ◽  
Reconstructive Surgery ◽  
3D Model ◽  
Surgical Intervention ◽  
Three Dimensional ◽  
Virtual Model ◽  
Virtual Planning ◽  
Augmented Reality Technology

Facial defects and deformations occupy a significant place in the practice of maxillofacial and dental surgeons. Nevertheless, maxillofacial surgery is developing rapidly and requires improvement of existing treatment methods, and introduction of new approaches to reconstructive surgery. Augmented reality is a promising direction of computer technology development which is actively used in medicine and education. Modern computer technology allows to create a 3D model of a lost organ and use it for preoperative planning, as well as apply a virtual model for intraoperative navigation. Recently, the method of augmented reality has been actively developed, when a virtual image of the zone of the surgical area or a dedicated organ is used, which is compared with its real prototype in static mode, or in real-time using computer devices. The benefits of using augmented reality technologies in reconstructive surgery is associated with preoperative virtual planning, simplification of the surgical intervention itself, as well as with a reduction in the risks of intra- and postoperative complications. The aim of our work was to study the opportunity of using the augmented reality technology in reconstructive surgery for microtia correction based on pre-operative computer simulation. At the preoperative stage, a photometric analysis of the patient was carried out, then a computer simulation of the missing auricle was performed. Using a 3D printer, a virtual model of the reconstructed auricle was obtained. The image in three-dimensional format was loaded into augmented reality glasses, which made it possible to project the shape and position of the simulated auricle to the area of the defect of the auricle when preparing for surgery. During the surgery, a marker was installed near the surgical field, in order to display the three-dimensional model in a destined position. During surgical intervention, an autogenous costal cartilage was taken, from which the auricle was formed using augmented reality approach and three-dimensional modeling. Subsequently, the graft was introduced to the formed bed in the area of the right ear auricle. The obtained 3D model of the auricle before the operation enabled planning of the forthcoming operation and determine the amount of autograft needed for reconstruction. Using the augmented reality glasses, the exact shape of the auricle is reproduced during the operation, and its proper position is assessed in relation to the healthy side. No complications were observed over the postoperative period. Virtual modelling of a lost or absent organ based on a preoperative examination provides important information about its spatial structure. Preoperative virtual planning allows you to predict the individual features of the operation, its difficult stages, to anticipate possible complications. The use of augmented reality technology during reconstructive surgery is a promising method requiring further development and improvement.

scholarly journals Computed tomographic analysis of cervical spine pedicles in the adult Indian population

2021 ◽  
Vol 12 ◽  
pp. 68
Author(s):  
Sanjeev Kumar ◽  
Naresh Kumar Saini ◽  
Devender Singh ◽  
Manish Chadha ◽  
Gopesh Mehrotra
Keyword(s):  
Cervical Spine ◽  
Indian Population ◽  
Three Dimensional ◽  
Pedicle Screws ◽  
Anatomical Variations ◽  
Ct Scans ◽  
Screw Insertion ◽  
Spine Pathology ◽  
Cervical Pedicle ◽  
The Mean

Background: Cervical pedicle screw insertion is a technically demanding procedure that carries the risk of catastrophic damage to surrounding neurovascular structures. Here, we analyzed computed tomography (CT)-based three-dimensional cervical spine pedicle geometry to determine the level and sex-specific morphologic differences in the adult Indian population. Methods: The CT scans of 200 patients (2400 pedicles) without significant cervical spine pathology were collected. The mean pedicle width (PW), pedicle height (PH), pedicle axial length (PAL), and pedicle transverse angle (PTA) from C2 to C7 were measured. Results: The smallest mean PW was at C3 in both males (4.85 ± 0.73 mm) and females (4.31 ± 0.43 mm); 7.08% of all pedicles were found to have mean PW of <4 mm. The smallest mean PH was at C5 in both males (6.25 ± 0.67mm) and females (5.54 ± 0.52 mm). The smallest mean PAL was at C2 in both males (27.46 ± 1.69mm) and females (25.90 ± 1.88 mm). The mean PW, PH, and PAL were significantly greater in males than females at all levels (P < 0.05). The smallest mean PTA was at C3 in males (41.79 ± 2.53°) and at C7 in females (42.40 ± 2.27°). Conclusion: In the adult Indian population, the PW, PH and PAL were smaller than in the typical western population. Females had even smaller PW, PH and PAL as compared to males. We recommend that a small inventory of 3.5mm screws between 20mm to 30mm length be used in most cases where cervical pedicle screws are being used in the Indian population. However, individual vertebrae should be screened preoperatively with CT scans to exclude gross anatomical variations, especially in females and at the C3 and C4 levels.

scholarly journals A Prospective Comparative Study between the Software Models and Clinical Models of Clear Aligner Treatment

2019 ◽  
Vol 9 (1) ◽  
pp. 28-34
Author(s):  
Arisha Izhar ◽  
Gurkeerat Singh ◽  
Varun Goyal ◽  
Rajkumar Singh ◽  
Nishant Gupta ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Three Dimensional ◽  
Prospective Clinical Study ◽  
Virtual Model ◽  
Posterior Teeth ◽  
Planning Stage ◽  
Anterior Crowding ◽  
Tooth Position ◽  
Software Models ◽  
The Mean

Introduction: The purpose of this prospective clinical study was to compare the three dimensional predicted software models with the stage clinical STL models and to evaluate the efficacy of tooth movement with clear aligners. Materials & Method: The sample size included 10 cases with mild anterior crowding treated with aligner therapy. The virtual model of the predicted tooth position was superimposed on the virtual model of the achieved tooth position at various stages over their stationary posterior teeth by using MeshLab software. The amount of tooth movement predicted was compared with the amount of tooth movement achieved. Result: The results of this study have shown that when a comparison was made on the basis of irregularity scores in both the groups, it was seen that the irregularity score was more in Clinical STL group at each stage such as 2.55 at T4, 1.65 at T6 and 1.0 at T8 whereas 2.0 at T4. 0.90 at T6 and 0.25 at T8 in the Software model group. Also, On comparing mean accuracy these three stages, the analysis of data showed the mean accuracy at T4 is 62.5%, mean accuracy at T6 is 68.8% and the mean accuracy at T8 is 78.1%. Conclusion: The predicted software models do not accurately reflect the patient’s tooth position .There is an overestimation by predicted software as compared to actual clinically achieved tooth position. There is a need of overcorrection to be built in the treatment planning stage itself and execution of the anticipated end result.

Electron Holographic Nano-Characterization of Gold Catalyst at Interface

2002 ◽  
Vol 727 ◽  
Author(s):  
S. Ichikawa ◽  
T. Akita ◽  
M. Okumura ◽  
M. Haruta ◽  
K. Tanaka
Keyword(s):  
Contact Angle ◽  
Titanium Oxide ◽  
Gold Catalyst ◽  
Three Dimensional ◽  
High Resolution Electron Microscopy ◽  
Electron Holography ◽  
Gold Particles ◽  
Oxide Support ◽  
The Mean ◽  
A Charge

AbstractThe catalytic properties of nanostructured gold catalyst are known to depend on the size of the gold particles and to be activated when the size decreases to a few nanometers. We investigated the size dependence of the three-dimensional nanostructure on the mean inner potential of gold catalysts supported on titanium oxide using electron holography and high-resolution electron microscopy (HREM). The contact angle of the gold particles on the titanium oxide tended to be over 90° for gold particles with a size of over 5 nm, and below 90° for a size of below 2 nm. This decreasing change in the contact angle (morphology) acts to increase the perimeter and hence the area of the interface between the gold and titanium oxide support, which is considered to be an active site for CO oxidation. The mean inner potential of the gold particles also changed as their size decreased. The value of the inner potential of gold, which is approximately 25 V in bulk state, rose to over 40 V when the size of the gold particles was less than 2 nm. This phenomenon indicates the existence of a charge transfer at the interface between gold and titanium oxide. The 3-D structure change and the inner potential change should be attributed to the specific electronic structure at the interface, owing to both the “nano size effect” and the “hetero-interface effect.”

The Influence of Blade Wakes on the Performance of Interturbine Diffusers

1996 ◽  
Vol 118 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. G. Dominy ◽  
D. A. Kirkham
Keyword(s):  
Performance Modeling ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Two Dimensional ◽  
Correct Performance ◽  
Analysis Methods ◽  
Flow Factor ◽  
The Mean ◽  
Lp Turbine

Interturbine diffusers provide continuity between HP and LP turbines while diffusing the flow upstream of the LP turbine. Increasing the mean turbine diameter offers the potential advantage of reducing the flow factor in the following stages, leading to increased efficiency. The flows associated with these interturbine diffusers differ from those in simple annular diffusers both as a consequence of their high-curvature S-shaped geometry and of the presence of wakes created by the upstream turbine. It is shown that even the simplest two-dimensional wakes result in significantly modified flows through such ducts. These introduce strong secondary flows demonstrating that fully three-dimensional, viscous analysis methods are essential for correct performance modeling.

scholarly journals Direct 3D model extraction method for color volume images

2021 ◽  
Vol 29 ◽  
pp. 133-140
Author(s):  
Bin Liu ◽  
Shujun Liu ◽  
Guanning Shang ◽  
Yanjie Chen ◽  
Qifeng Wang ◽  
...  
Keyword(s):  
3D Model ◽  
Clinical Medicine ◽  
Three Dimensional ◽  
Laplacian Matrix ◽  
Segmentation Method ◽  
Human Organs ◽  
Model Segmentation ◽  
Treatment Objective ◽  
Organ Models ◽  
Different Parts

BACKGROUND: There is a great demand for the extraction of organ models from three-dimensional (3D) medical images in clinical medicine diagnosis and treatment. OBJECTIVE: We aimed to aid doctors in seeing the real shape of human organs more clearly and vividly. METHODS: The method uses the minimum eigenvectors of Laplacian matrix to automatically calculate a group of basic matting components that can properly define the volume image. These matting components can then be used to build foreground images with the help of a few user marks. RESULTS: We propose a direct 3D model segmentation method for volume images. This is a process of extracting foreground objects from volume images and estimating the opacity of the voxels covered by the objects. CONCLUSIONS: The results of segmentation experiments on different parts of human body prove the applicability of this method.

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