scholarly journals Identifying Thrombus on Non-Contrast CT in Patients with Acute Ischemic Stroke

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1919
Author(s):  
Shakeel Qazi ◽  
Emmad Qazi ◽  
Alexis T. Wilson ◽  
Connor McDougall ◽  
Fahad Al-Ajlan ◽  
...  
Keyword(s):  
Operating Characteristic ◽  
Linear Regression Analysis ◽  
Three Dimensional ◽  
Hounsfield Unit ◽  
3D Models ◽  
Patient Specific ◽  
Characteristic Analysis ◽  
Thin Slice ◽  
Three Dimensional Models ◽  
Contrast Ct

The hyperdense sign is a marker of thrombus in non-contrast computed tomography (NCCT) datasets. The aim of this work was to determine optimal Hounsfield unit (HU) thresholds for thrombus segmentation in thin-slice non-contrast CT (NCCT) and use these thresholds to generate 3D thrombus models. Patients with thin-slice baseline NCCT (≤2.5 mm) and MCA-M1 occlusions were included. CTA was registered to NCCT, and three regions of interest (ROIs) were placed in the NCCT, including: the thrombus, contralateral brain tissue, and contralateral patent MCA-M1 artery. Optimal HU thresholds differentiating the thrombus from non-thrombus tissue voxels were calculated using receiver operating characteristic analysis. Linear regression analysis was used to predict the optimal HU threshold for discriminating the clot only based on the average contralateral vessel HU or contralateral parenchyma HU. Three-dimensional models from 70 participants using standard (45 HU) and patient-specific thresholds were generated and compared to CTA clot characteristics. The optimal HU threshold discriminating thrombus in NCCT from other structures varied with a median of 51 (IQR: 49–55). Experts chose 3D models derived using patient-specific HU models as corresponding better to the thrombus seen in CTA in 83.8% (31/37) of cases. Patient-specific HU thresholds for segmenting the thrombus in NCCT can be derived using normal parenchyma. Thrombus segmentation using patient-specific HU thresholds is superior to conventional 45 HU thresholds.

scholarly journals Additive Manufacturing for Neurosurgery: Digital Light Processing of Individualized Patient-Specific Cerebral Aneurysms

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6057
Author(s):  
Stefano Guarino ◽  
Enrico Marchese ◽  
Gennaro Salvatore Ponticelli ◽  
Alba Scerrati ◽  
Vincenzo Tagliaferri ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cerebral Aneurysms ◽  
3D Models ◽  
Patient Specific ◽  
Digital Light Processing ◽  
Direct Light ◽  
Supporting Tool ◽  
Three Dimensional Models ◽  
3D Printing Technique ◽  
Surgical Operations

This study aims at demonstrating the feasibility of reproducing individualized patient-specific three-dimensional models of cerebral aneurysms by using the direct light processing (DLP) 3D printing technique in a low-time and inexpensive way. Such models were used to help neurosurgeons understand the anatomy of the aneurysms together with the surrounding vessels and their relationships, providing, therefore, a tangible supporting tool with which to train and plan surgical operations. The starting 3D models were obtained by processing the computed tomography angiographies and the digital subtraction angiographies of three patients. Then, a 3D DLP printer was used to print the models, and, if acceptable, on the basis of the neurosurgeon’s opinion, they were used for the planning of the neurosurgery operation and patient information. All the models were printed within three hours, providing a comprehensive representation of the cerebral aneurysms and the surrounding structures and improving the understanding of their anatomy and simplifying the planning of the surgical operation.

scholarly journals Comparative Analysis of Digital Models of Objects of Cultural Heritage Obtained by the “3D SLS” and “SfM” Methods

2021 ◽  
Vol 11 (12) ◽  
pp. 5321
Author(s):  
Marcin Barszcz ◽  
Jerzy Montusiewicz ◽  
Magdalena Paśnikowska-Łukaszuk ◽  
Anna Sałamacha
Keyword(s):  
Cultural Heritage ◽  
Low Cost ◽  
Three Dimensional ◽  
3D Models ◽  
Silk Road ◽  
Digital Models ◽  
Global Pandemic ◽  
University Of Technology ◽  
Three Dimensional Models ◽  
3D Digitisation

In the era of the global pandemic caused by the COVID-19 virus, 3D digitisation of selected museum artefacts is becoming more and more frequent practice, but the vast majority is performed by specialised teams. The paper presents the results of comparative studies of 3D digital models of the same museum artefacts from the Silk Road area generated by two completely different technologies: Structure from Motion (SfM)—a method belonging to the so-called low-cost technologies—and by Structured-light 3D Scanning (3D SLS). Moreover, procedural differences in data acquisition and their processing to generate three-dimensional models are presented. Models built using a point cloud were created from data collected in the Afrasiyab museum in Samarkand (Uzbekistan) during “The 1st Scientific Expedition of the Lublin University of Technology to Central Asia” in 2017. Photos for creating 3D models in SfM technology were taken during a virtual expedition carried out under the “3D Digital Silk Road” program in 2021. The obtained results show that the quality of the 3D models generated with SfM differs from the models from the technology (3D SLS), but they may be placed in the galleries of the vitrual museum. The obtained models from SfM do not have information about their size, which means that they are not fully suitable for archiving purposes of cultural heritage, unlike the models from SLS.

scholarly journals Improving 3D-3D facial registration methods: potential role of three-dimensional models in personal identification of the living

2021 ◽  
Author(s):  
Daniele Gibelli ◽  
Andrea Palamenghi ◽  
Pasquale Poppa ◽  
Chiarella Sforza ◽  
Cristina Cattaneo ◽  
...  
Keyword(s):  
Three Dimensional ◽  
3D Models ◽  
Personal Identification ◽  
Surveillance Systems ◽  
3D Registration ◽  
Three Dimensional Models ◽  
Point To Point ◽  
Point Distance ◽  
Male Subjects

AbstractPersonal identification of the living from video surveillance systems usually involves 2D images. However, the potentiality of three-dimensional facial models in gaining personal identification through 3D-3D comparison still needs to be verified. This study aims at testing the reliability of a protocol for 3D-3D registration of facial models, potentially useful for personal identification. Fifty male subjects aged between 18 and 45 years were randomly chosen from a database of 3D facial models acquired through stereophotogrammetry. For each subject, two acquisitions were available; the 3D models of faces were then registered onto other models belonging to the same and different individuals according to the least point-to-point distance on the entire facial surface, for a total of 50 matches and 50 mismatches. RMS value (root mean square) of point-to-point distance between the two models was then calculated through the VAM® software. Intra- and inter-observer errors were assessed through calculation of relative technical error of measurement (rTEM). Possible statistically significant differences between matches and mismatches were assessed through Mann–Whitney test (p < 0.05). Both for intra- and inter-observer repeatability rTEM was between 2.2 and 5.2%. Average RMS point-to-point distance was 0.50 ± 0.28 mm in matches, 2.62 ± 0.56 mm in mismatches (p < 0.01). An RMS threshold of 1.50 mm could distinguish matches and mismatches in 100% of cases. This study provides an improvement to existing 3D-3D superimposition methods and confirms the great advantages which may derive to personal identification of the living from 3D facial analysis.

Combining patient-specific, digital 3D models with tele-education for adolescents with CHD

2021 ◽  
pp. 1-6
Author(s):  
David Liddle ◽  
Sheri Balsara ◽  
Karin Hamann ◽  
Adam Christopher ◽  
Laura Olivieri ◽  
...  
Keyword(s):  
Medical Condition ◽  
Three Dimensional ◽  
Medical Knowledge ◽  
3D Models ◽  
Patient Specific ◽  
Coarctation Of Aorta ◽  
Education Session ◽  
Post Intervention ◽  
Cardiac Defects ◽  
Transposition Of Great Arteries

Abstract Introduction: Adolescents with CHD require transition to specialised adult-centred care. Previous studies have shown that adolescents’ knowledge of their medical condition is correlated with transition readiness. Three-dimensional printed models of CHD have been used to educate medical trainees and patients, although no studies have focused on adolescents with CHD. This study investigates the feasibility of combining patient-specific, digital 3D heart models with tele-education interventions to improve the medical knowledge of adolescents with CHD. Methods: Adolescent patients with CHD, aged between 13 and 18 years old, were enrolled and scheduled for a tele-education session. Patient-specific digital 3D heart models were created using images from clinically indicated cardiac magnetic resonance studies. The tele-education session was performed using commercially available, web-conferencing software (Zoom, Zoom Video Communications Inc.) and a customised software (Cardiac Review 3D, Indicated Inc.) incorporating an interactive display of the digital 3D heart model. Medical knowledge was assessed using pre- and post-session questionnaires that were scored by independent reviewers. Results: Twenty-two adolescents completed the study. The average age of patients was 16 years old (standard deviation 1.5 years) and 56% of patients identified as female. Patients had a variety of cardiac defects, including tetralogy of Fallot, transposition of great arteries, and coarctation of aorta. Post-intervention, adolescents’ medical knowledge of their cardiac defects and cardiac surgeries improved compared to pre-intervention (p < 0.01). Conclusions: Combining patient-specific, digital 3D heart models with tele-education sessions can improve adolescents’ medical knowledge and may assist with transition to adult-centred care.

scholarly journals Creation of virtual 3D models of the existing architectonic structures using the web resources

Spatium ◽  
2016 ◽  
pp. 30-36 ◽  
Author(s):  
Petar Pejic ◽  
Sonja Krasic
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
3D Models ◽  
Three Dimensional Model ◽  
Web Resources ◽  
Existing Structures ◽  
Software Packages ◽  
Physical Presence ◽  
The Creation ◽  
Three Dimensional Models

Digital three-dimensional models of the existing architectonic structures are created for the purpose of digitalization of the archive documents, presentation of buildings or an urban entity or for conducting various analyses and tests. Traditional methods for the creation of 3D models of the existing buildings assume manual measuring of their dimensions, using the photogrammetry method or laser scanning. Such approaches require considerable time spent in data acquisition or application of specific instruments and equipment. The goal of this paper is presentation of the procedure for the creation of 3D models of the existing structures using the globally available web resources and free software packages on standard PCs. This shortens the time of the production of a digital three-dimensional model of the structure considerably and excludes the physical presence at the location. In addition, precision of this method was tested and compared with the results acquired in a previous research.

scholarly journals Processing Three-Dimensional Models of Archaeological Artifacts

2021 ◽  
Vol 20 (7) ◽  
pp. 48-61
Author(s):  
Pavel V. Chistyakov ◽  
Ekaterina N. Bocharova ◽  
Ksenia A. Kolobova
Keyword(s):  
Three Dimensional ◽  
3D Models ◽  
International Standards ◽  
Post Processing ◽  
Three Dimensional Model ◽  
Scaled Model ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Dimensional Models ◽  
Three Dimensional Models

This article provides a detailed account of the process of scanning, post-processing and further manipulation of three-dimensional models obtained with structured light scanners. Purpose. The purpose of the study is determined by the need for national archaeologists to learn the methods of three-dimensional modeling for the implementation of scientific research corresponding to international standards. Unfortunately, this direction in national archaeology began to develop in a relatively recent time and there is a lag in the application of three-dimensional modeling of national archaeology compared to the world level. Results. Any archaeological, experimental or ethnographic artifact can be used for three-dimensional scanning. To perform post-processing of three-dimensional models it is necessary to carry out primary scanning of an artifact by one of the existing algorithms. The algorithm for creating models, their positioning, simplification, saving in various formats and export is described. The main sequence of 3D models post-processing includes: processing of groups of scanned projections (their cleaning and alignment), creation of artifact model and processing/rectification of the resulting model using special software. Conclusion. As a result of correct implementation of the algorithm, the researcher receives a scaled model completely corresponding to the original artifact. Obtaining a scalable, texture-free three-dimensional model of the artifact, which fully corresponds to the original and exceeds a photograph in the quality of detail transfer, allows a scientist to conduct precise metric measurements and any procedures of non-invasive manipulation of the models. The ability to access a database of three-dimensional models of archaeological collections greatly simplifies the work of archaeologists, especially in situations when country borders are closed.

Impact of image reconstruction parameters when using 3D DSA reconstructions to measure intracranial aneurysms

2017 ◽  
Vol 10 (3) ◽  
pp. 285-289 ◽  
Author(s):  
Katrina L Ruedinger ◽  
David R Rutkowski ◽  
Sebastian Schafer ◽  
Alejandro Roldán-Alzate ◽  
Erick L Oberstar ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Hounsfield Unit ◽  
Ground Truth ◽  
Individual Case ◽  
Dome Height ◽  
Patient Specific ◽  
Analysis Tool ◽  
Accuracy Of Measurements ◽  
Image Characteristic

Background and purposeSafe and effective use of newly developed devices for aneurysm treatment requires the ability to make accurate measurements in the angiographic suite. Our purpose was to determine the parameters that optimize the geometric accuracy of three-dimensional (3D) vascular reconstructions.MethodsAn in vitro flow model consisting of a peristaltic pump, plastic tubing, and 3D printed patient-specific aneurysm models was used to simulate blood flow in an intracranial aneurysm. Flow rates were adjusted to match values reported in the literature for the internal carotid artery. 3D digital subtraction angiography acquisitions were obtained using a commercially available biplane angiographic system. Reconstructions were done using Edge Enhancement (EE) or Hounsfield Unit (HU) kernels and a Normal or Smooth image characteristic. Reconstructed images were analyzed using the vendor's aneurysm analysis tool. Ground truth measurements were derived from metrological scans of the models with a microCT. Aneurysm volume, surface area, dome height, minimum and maximum ostium diameter were determined for the five models.ResultsIn all cases, measurements made with the EE kernel most closely matched ground truth values. Differences in values derived from reconstructions displayed with Smooth or Normal image characteristics were small and had only little impact on the geometric parameters considered.ConclusionsReconstruction parameters impact the accuracy of measurements made using the aneurysm analysis tool of a commercially available angiographic system. Absolute differences between measurements made using reconstruction parameters determined as optimal in this study were, overall, very small. The significance of these differences, if any, will depend on the details of each individual case.

Evaluation of Spherical Parameterization Methods for Three-Dimensional Reconstruction of Medical Images

2013 ◽  
Vol 365-366 ◽  
pp. 1342-1349
Author(s):  
Xing Hui Wu ◽  
Zhi Xiu Hao
Keyword(s):  
Medical Images ◽  
Three Dimensional ◽  
3D Models ◽  
Mapping Method ◽  
Geometric Error ◽  
Patient Specific ◽  
Shape Modelling ◽  
Dimensional Reconstruction ◽  
Statistical Shape ◽  
Spherical Parameterization

The spherical parameterization is important for the correspondence problem that is a major part of statistical shape modelling for the reconstruction of patient-specific 3D models from medical images. In this paper, we present comparative studies of five common spherical mapping methods applied to the femur and tibia models: the Issenburg et al. method, the Alexa method, the Saba et al. method, the Praun et al. method and the Shen et al. method. These methods are evaluated using three sets of measures: distortion property, geometric error and distance to standard landmarks. Results show that the Praun et al. method performs better than other methods while the Shen et al. method can be regarded as the most reliable one for providing an acceptable correspondence result. We suggest that the area preserving property can be used as a sufficient condition while the angle preserving property is not important when choosing a spherical mapping method for correspondence application.

Placing Three-Dimensional Models in an Uncalibrated Single Image of an Architectural Scene

2004 ◽  
Vol 13 (6) ◽  
pp. 692-707 ◽  
Author(s):  
Sara Keren ◽  
Ilan Shimshoni ◽  
Ayellet Tal
Keyword(s):  
Augmented Reality ◽  
Three Dimensional ◽  
3D Models ◽  
Automatic Extraction ◽  
Single Image ◽  
Vanishing Points ◽  
Correct Position ◽  
3D Objects ◽  
Position And Orientation ◽  
Three Dimensional Models

This paper discusses the problem of inserting 3D models into a single image. The main focus of the paper is on the accurate recovery of the camera's parameters, so that 3D models can be inserted in the “correct” position and orientation. The paper addresses two issues. The first is an automatic extraction of the principal vanishing points from an image. The second is a theoretical and an experimental analysis of the errors. To test the concept, a system that “plants” virtual 3D objects in the image was implemented. It was tested on many indoor augmented-reality scenes. Our analysis and experiments have shown that errors in the placement of the objects are unnoticeable.

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