scholarly journals 3D-Volume Rendering of the Pelvis with Emphasis on Paraurethral Structures Based on MRI Scans and Comparisons between 3D Slicer and OsiriX®

2021 ◽  
Vol 45 (3) ◽  
Author(s):  
C. M. Durnea ◽  
S. Siddiqi ◽  
D. Nazarian ◽  
G. Munneke ◽  
P. M. Sedgwick ◽  
...  
Keyword(s):  
Image Processing ◽  
Secondary Analysis ◽  
Three Dimensional ◽  
3D Models ◽  
Clinical Role ◽  
Cross Sectional ◽  
3D Slicer ◽  
Mri Scans ◽  
3D Volume ◽  
Good Agreement

AbstractThe feasibility of rendering three dimensional (3D) pelvic models of vaginal, urethral and paraurethral lesions from 2D MRI has been demonstrated previously. To quantitatively compare 3D models using two different image processing applications: 3D Slicer and OsiriX. Secondary analysis and processing of five MRI scan based image sets from female patients aged 29–43 years old with vaginal or paraurethral lesions. Cross sectional image sets were used to create 3D models of the pelvic structures with 3D Slicer and OsiriX image processing applications. The linear dimensions of the models created using the two different methods were compared using Bland-Altman plots. The comparisons demonstrated good agreement between measurements from the two applications. The two data sets obtained from different image processing methods demonstrated good agreement. Both 3D Slicer and OsiriX can be used interchangeably and produce almost similar results. The clinical role of this investigation modality remains to be further evaluated.

Analysis of Insole Geometry and Deformity by Using a Three-Dimensional Image Processing Technique: A Preliminary Study

2019 ◽  
Vol 109 (2) ◽  
pp. 98-107
Author(s):  
Kit-lun Yick ◽  
Wai-ting Lo ◽  
Sun-pui Ng ◽  
Joanne Yip ◽  
Hung-hei Kwan ◽  
...  
Keyword(s):  
Image Processing ◽  
Cross Sections ◽  
Plantar Pressure ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Diabetic Patients ◽  
Clinical Practices ◽  
Cross Sectional ◽  
Orthotic Treatment

Background: Accurate representation of the insole geometry is crucial for the development and performance evaluation of foot orthoses designed to redistribute plantar pressure, especially for diabetic patients. Methods: Considering the limitations in the type of equipment and space available in clinical practices, this study adopted a simple portable three-dimensional (3-D) desktop scanner to evaluate the 3-D geometry of an orthotic insole and the corresponding deformities after the insole has been worn. The shape of the insole structure along horizontal cross sections is defined with 3-D scanning and image processing. Accompanied by an in-shoe pressure measurement system, plantar pressure distribution in four foot regions (hallux, metatarsal heads, midfoot, and heel) is analyzed and evaluated for insole deformity. Results: Insole deformities are quantified across the four foot regions. The hallux region tends to show the greatest changes in shape geometry (17%–50%) compared with the other foot regions after 2 months of insole wear. As a result of insole deformities, plantar peak pressures change considerably (–4.3% to +69.5%) during the course of treatment. Conclusions: Changes in shape geometry of the insoles could be objectively quantified with 3-D scanning techniques and image processing. This investigation finds that, in general, the design of orthotic insoles may not be adequate for diabetic individuals with similar foot problems. The drastic changes in the insole shape geometry and cross-sectional areas during orthotic treatment may reduce insole fit and conformity. An inadequate insole design may also affect plantar pressure reduction. The approach proposed herein, therefore, allows for objective quantification of insole shape geometry, which results in effective and optimal orthotic treatment.

A Hybrid Model for Predicting Gas Entrainment in a Small Branch From a Co-Current Flowing Gas-Liquid Regime

2010 ◽  
Author(s):  
Robert Bowden ◽  
Wael Saleh ◽  
Ibrahim Hassan
Keyword(s):  
Digital Imaging ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Critical Conditions ◽  
Inertial Effects ◽  
Cross Sectional ◽  
Gas Entrainment ◽  
Small Branch ◽  
Dip Angle ◽  
Good Agreement

An analytical model was developed to predict the critical conditions at the onset of gas entrainment in a single downward oriented branch. The branch was installed on a horizontal square cross-sectional channel having a smooth stratified co-currently flowing gas-liquid regime in the upstream inlet region. The branch flow was simulated as a three-dimensional point-sink while the downstream run flow was treated with a uniform velocity at the critical dip location. A boundary condition was imposed in the model whereby the flow distribution between the branch and run was obtained experimentally and digital imaging was used to quantify the critical dip location through the dip angle. Three constant dip angles were evaluated in the model and results showed the dip height to have good agreement with experiments between angles of 50 and 60 degrees. The predicted upstream height, however, did not match well with the experimentally determined height due to the omission of shear and inertial effects between the upstream location and critical dip.

scholarly journals Accuracy of 2D modeling approach for performance simulation of noncircular single- and dual-layer monolithic catalysts

2021 ◽  
Author(s):  
Behnam Mozaffari
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Single Layer ◽  
Flow Region ◽  
3D Models ◽  
Catalytic Performance ◽  
Cross Sectional ◽  
2D Modeling ◽  
Modeling Approach ◽  
Monolithic Catalysts

This study aims to evaluate the accuracy of widely applied approach of modeling noncircular channels and washcoats of monolithic catalysts with equivalent circular geometrical shapes. For this purpose, catalytic performance of equivalent circular and square channel cross-sectional shapes with single-layer Pt/Al2O3 and dual-layer Fe-ZSM-5+Pt/Al2O3 washcoats are investigated. For the noncircular cross-sections, three-dimensional computational fluid dynamics models that consider species gases convection inside the channel bulk flow region, and reaction and diffusion of species inside the washcoat layer(s) are utilized to simulate the performance of one channel of the monolithic catalytic converters. In addition, in order to investigate the amount of inaccuracy of 2D modeling approach for noncircular channels, 2D models are applied to simulate the equivalent monolithic catalysts with circular cross-sections, and the results of the 2D and 3D models are compared together, and also, with the experimental and 1D+1D modeling technique results available in the literature.

scholarly journals Numerical Investigation on Steel Square HSS Columns Strengthened with Polymer-mortar

2019 ◽  
pp. 1-25
Author(s):  
Khaled M. El-Sayed ◽  
Ahmed S. Debaiky ◽  
Nader N. Khalil ◽  
Ibrahim M. El-Shenawy
Keyword(s):  
Three Dimensional ◽  
Shell Element ◽  
Fe Analysis ◽  
Experimental Results ◽  
Fe Model ◽  
Cross Sectional ◽  
Axial Strength ◽  
Polymer Mortar ◽  
Slender Columns ◽  
Good Agreement

This paper presents the results of finite element (FE) analysis of axially loaded square hollow structural steel (HSS) columns, strengthened with polymer-mortar materials. Three-dimensional nonlinear FE model of HSS slender columns were developed using thin-shell element, considering geometric and material nonlinearity. The polymer-mortar strengthening layer was incorporated using additional layers of the shell element. The FE model has been performed and then verified against experimental results obtained by the authors [1]. Good agreement was observed between FE analysis and experimental results. The model was then used in an extended parametric study to examine selected AISC square HSS columns with different cross-sectional geometries, slenderness ratios, thicknesses of mortar strengthening layer, overall geometric imperfections, and level of residual stresses. The effectiveness of polymer-mortar in increasing the column’s axial strength is observed. The study also demonstrated that polymer-mortar strengthening materials is more effective for higher slenderness ratios. An equivalent steel thickness is also accounted for the mortar strengthened HSS columns to discuss the effectiveness of polymer-mortar strengthening system. The polymer-mortar strengthening system is more effective for HSS columns with higher levels of out-of-straightness. Level of residual stress has a slight effect on the gain in the column’s axial strength strengthened with polymer-mortar.

scholarly journals 3D reconstruction of ablation lesions from in-vitro preparations using MRI

2017 ◽  
Vol 3 (2) ◽  
pp. 437-440 ◽  
Author(s):  
Stefan Pollnow ◽  
Areg Noshadi ◽  
Michael Kircher ◽  
Gisela Guthausen ◽  
Thomas Oerther ◽  
...  
Keyword(s):  
Image Processing ◽  
Cardiac Electrophysiology ◽  
Three Dimensional ◽  
Rapid Acquisition ◽  
3D Geometry ◽  
Magnetic Resonance Imaging Mri ◽  
3D Volume ◽  
Steady State Precession ◽  
Weighted Sequences

AbstractRadiofrequency ablation is the gold standard for treating cardiac arrhythmias. However, the success rate of this procedure depends on numerous parameters. Wet lab experiments provide the opportunity to investigate cardiac electrophysiology under reproducible conditions. To evaluate the electrophysiological changes of ablated myocardium in these studies it is necessary to consider the three-dimensional (3D) geometry of the lesions. For this purpose, we investigated the usage of different magnetic resonance imaging (MRI) sequences as well as an image processing procedure to analyze in-vitro preparations. To differentiate signal intensities between nonablated and ablated tissue we evaluated FISP (fast imaging with steady-state precession; delivering dominantly T1-weighted images) and RARE (rapid acquisition with relaxation enhancement; delivering dominantly T2-weighted images). After image processing, the ablated tissue was segmented in each image slice forming a 3D volume. The geometry of the lesion was modeled by the boundary of this volume. It was generally feasible to distinguish between healthy myocardium and ablated tissue as well as to determine lesion transmurality. The analysis of the reconstructed lesion geometries from FISP and RARE MRI showed a high agreement, however T2-weighted sequences showed larger lesion volumes as well as higher variations in segmentation compared to T1- mapping. FISP with higher quality may be used to reconstruct the 3D geometry of the ablation lesions.

scholarly journals A Comprehensive Observational Study of Graupel and Hail Terminal Velocity, Mass Flux, and Kinetic Energy

2018 ◽  
Vol 75 (11) ◽  
pp. 3861-3885 ◽  
Author(s):  
Andrew Heymsfield ◽  
Miklós Szakáll ◽  
Alexander Jost ◽  
Ian Giammanco ◽  
Robert Wright
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
Mass Flux ◽  
Three Dimensional ◽  
Acrylonitrile Butadiene Styrene ◽  
Terminal Velocity ◽  
Three Dimensions ◽  
Cross Sectional ◽  
Wide Range ◽  
3D Volume

Abstract This study uses novel approaches to estimate the fall characteristics of hail, covering a size range from about 0.5 to 7 cm, and the drag coefficients of lump and conical graupel. Three-dimensional (3D) volume scans of 60 hailstones of sizes from 2.5 to 6.7 cm were printed in three dimensions using acrylonitrile butadiene styrene (ABS) plastic, and their terminal velocities were measured in the Mainz, Germany, vertical wind tunnel. To simulate lump graupel, 40 of the hailstones were printed with maximum dimensions of about 0.2, 0.3, and 0.5 cm, and their terminal velocities were measured. Conical graupel, whose three dimensions (maximum dimension 0.1–1 cm) were estimated from an analytical representation and printed, and the terminal velocities of seven groups of particles were measured in the tunnel. From these experiments, with printed particle densities from 0.2 to 0.9 g cm−3, together with earlier observations, relationships between the drag coefficient and the Reynolds number and between the Reynolds number and the Best number were derived for a wide range of particle sizes and heights (pressures) in the atmosphere. This information, together with the combined total of more than 2800 hailstones for which the mass and the cross-sectional area were measured, has been used to develop size-dependent relationships for the terminal velocity, the mass flux, and the kinetic energy of realistic hailstones.

CONSTRUCTION OF ANATOMICALLY ACCURATE FINITE ELEMENT MODELS OF THE HUMAN HAND AND A RAT KIDNEY

2011 ◽  
Vol 11 (05) ◽  
pp. 1141-1164 ◽  
Author(s):  
LI ZHONG MU ◽  
HONG WEI SHAO ◽  
YING HE ◽  
TOSHIAKI ODA ◽  
XUE MEI JIA
Keyword(s):  
Image Processing ◽  
Finite Element ◽  
Rat Kidney ◽  
Three Dimensional ◽  
3D Models ◽  
Human Hand ◽  
Finite Element Models ◽  
Transfinite Interpolation ◽  
Boundary Information ◽  
Magnetic Resonance Imaging Mri

The aim of the paper is to develop a method for generating three-dimensional (3D) models of organs from medical images (computerized tomography (CT) images, magnetic resonance imaging (MRI), etc.). There were three main steps in the development of the model: the first step was image processing. Different image-processing operators including blurring, sharpening, edge detection, region segmentation, mathematical morphology transformation, rotation, and movement of the kidney slices were performed to automatically construct the accurate boundary information. The second step was mesh generation of each slice based on the boundary information by using the transfinite interpolation (TFI) technique. In this paper, the TFI method was improved to create grids from images directly. The last step was reconstructing the models by stacking the 2D grid models and visualizing the result in the Advanced Visual System (AVS) software. In order to verify the effectiveness of this method, the finite element (FE) models of a rat kidney, human hand, and blood vessels were reconstructed and good results were obtained.

scholarly journals Frontal Cryosectioning: An Improved Protocol for Sectioning Large Areas of Fibrous Scaffolds

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Casey P. Grey ◽  
David G. Simpson
Keyword(s):  
Cross Sections ◽  
Imaging Techniques ◽  
Fibrous Tissue ◽  
Three Dimensional ◽  
3D Models ◽  
Spatial Cues ◽  
Tissue Engineering Scaffolds ◽  
Cross Sectional ◽  
Fibrous Scaffolds ◽  
Scaffold Properties

Fibrous tissue engineering scaffolds, such as those produced by electrospinning, cannot achieve their clinical potential until deep cell-scaffold interactions are understood. Even the most advanced imaging techniques are limited to capturing data at depths of 100 µm due to light scatter associated with the fibers that compose these scaffolds. Conventional cross-sectional analysis provides information on relatively small volumes of space and frontal sections are difficult to generate. Current understanding of cellular penetration into fibrous scaffolds is limited predominantly to the scaffold surface. Although some information is available from cross-sections, sections vary in quality, can distort spatial scaffold properties, and offer virtually no spatial cues as to what scaffold properties instigate specific cellular responses. Without the definitive ability to understand how cells interact with the architecture of an entire scaffold it is difficult to justify scaffold modifications or in-depth cell penetration analyses until appropriate techniques are developed. To address this limitation we have developed a cryosectioning protocol that makes it possible to obtain serial frontal sections from electrospun scaffolds. Microscopic images assembled into montage images from serial sections were then used to create three-dimensional (3D) models of cellular infiltration throughout the entire scaffold.

Image-Based Morphometry and Airflow Simulation in Rat Lungs

2010 ◽  
Author(s):  
Jessica M. Oakes ◽  
Alison L. Marsden ◽  
Miriam Scadeng ◽  
Chantal Darquenne
Keyword(s):  
Boundary Conditions ◽  
Flow Resistance ◽  
Three Dimensional ◽  
Airborne Particulate Matter ◽  
Aerosol Deposition ◽  
3D Models ◽  
Detailed Knowledge ◽  
Cross Sectional ◽  
Rat Lungs ◽  
Invasive Techniques

Detailed knowledge of the fate of aerosols in the lung is essential in understanding the effect of exposure to airborne particulate matter and infectious agents and in assessing the efficiency of inhaled drug therapy. Detailed, yet non-invasive, studies of peripheral aerosol deposition are almost impossible in humans. Thus, understanding the fate of aerosols in the lung requires the use of computational and/or animal models in which more invasive techniques can be used. In this study, using magnetic resonance (MR) images of rat lungs, we (1) built three dimensional (3D) models of the airway tree and (2) quantified lobar volumes. Flow simulations were then performed in one of the airway models. Flow conditions were set to be similar to that used in an experimental study where rats were exposed to aerosols [1]. Airflow boundary conditions at the outlets of the airways are unknown and therefore typically a zero pressure boundary condition is prescribed [2]. To test the validity of the zero pressure condition, two types of boundary conditions were described: (a) zero pressure at each of the outlets and (b) flow resistance at each outlet. Flow resistance allows for the flow rate distribution to be defined based on lung volume and airway cross sectional area. The flow results from the computational model may be used to solve the particle dynamics equation and therefore allow for future comparison with the ventilation experiments.

scholarly journals Effect of Uncertainty in Localized Imperfection on the Ultimate Compressive Strength of Cold-Formed Stainless Steel Hollow Sections

2019 ◽  
Vol 9 (18) ◽  
pp. 3827 ◽  
Author(s):  
Yanfei Shen ◽  
Rolando Chacón
Keyword(s):  
Stainless Steel ◽  
Compressive Strength ◽  
Three Dimensional ◽  
Local Buckling ◽  
Cost Effective ◽  
3D Models ◽  
Ultimate Compressive Strength ◽  
Cross Sectional ◽  
Hollow Section

Stainless steel has excellent corrosion resistance properties, considerable long-term durability, and good mechanical strength. Hollow sections are a versatile and efficient form for construction applications. The use of cold-formed stainless steel rectangular hollow section (RHS) and square hollow section (SHS) in construction industry grasps the attention of designers conceiving long-term, cost-effective structures. For cold-formed RHS and SHS, localized imperfection (ω) resulting from rolling and fabrication process is inevitable. ω has inherent variability and has no definitive characterization. In this paper, statistical analysis of the maximum value of ω collected from available experimental data is conducted. A new approach utilizing Fourier series to generate the three-dimensional (3D) models of members with random ω is proposed. Probabilistic studies based on the proposed 3D models are then carried out to evaluate the effect of uncertainty in ω on the ultimate compressive strength of stainless steel columns with cold-formed RHS and SHS. A total of 21 columns that are prone to local buckling reduction are studied. The results show that uncertainty in ω has a considerable influence on the columns with relatively higher cross-sectional slenderness.

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