scholarly journals Quantifying avian inertial properties using calibrated computed tomography

2022 ◽  
Vol 225 (1) ◽  
Author(s):  
Nicholas E. Durston ◽  
Yusuf Mahadik ◽  
Shane P. Windsor
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Ct Scans ◽  
Birds Of Prey ◽  
Distribution Data ◽  
Centre Of Mass ◽  
Body Segment ◽  
Dynamics Modelling ◽  
Non Destructive

ABSTRACT Estimating centre of mass and mass moments of inertia is an important aspect of many studies in biomechanics. Characterising these parameters accurately in three dimensions is challenging with traditional methods requiring dissection or suspension of cadavers. Here, we present a method to quantify the three-dimensional centre of mass and inertia tensor of birds of prey using calibrated computed tomography (CT) scans. The technique was validated using several independent methods, providing body segment mass estimates within approximately 1% of physical dissection measurements and moment of inertia measurements with a 0.993 R2 correlation with conventional trifilar pendulum measurements. Calibrated CT offers a relatively straightforward, non-destructive approach that yields highly detailed mass distribution data that can be used for three-dimensional dynamics modelling in biomechanics. Although demonstrated here with birds, this approach should work equally well with any animal or appendage capable of being CT scanned.

Precision, Repeatability, and Validation of the Localization of Cranial Landmarks Using Computed Tomography Scans

1995 ◽  
Vol 32 (3) ◽  
pp. 217-227 ◽  
Author(s):  
Joan T. Richtsmeier ◽  
Chul H. Paik ◽  
Peter C. Elfert ◽  
Theodore M. Cole ◽  
Holly R. Dahlman
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Ct Scans ◽  
Average Error ◽  
Measurement Systems ◽  
Three Dimensional Representation ◽  
Internal Structures ◽  
Means Of Measurement ◽  
Ct Data

Computed tomography (CT) has brought to the craniofacial surgeon a three-dimensional representation of internal structures. CT scans provide visualization of anatomy for preoperative planning and postoperative evaluation. Beyond visualization, however, a CT scan enables assessment of measurements useful to clinicians and basic scientists. All measurement systems used with CT require the ability to accurately locate regions of interest on the image (i.e., areas, volumes, outlines, curves, surfaces, points). This study evaluates the precision and repeatability of locating anatomic landmarks in three dimensions on CT slice images, and validates these locations using an established measurement system. The average error of landmark position is always less than 0.5 mm and for some landmarks error is negligible. Repeatability studies show that less than 2% of the total variance in our data is due to measurement inaccuracy. Although data collected from CT scans are internally consistent, validation results caution the use of CT data In combination with data collected using calipers or other direct means of measurement.

X-RAY TOMOGRAPHY STUDIES OF PREHISTORIC CERAMIC ARTIFACTS

2014 ◽  
Vol 27 ◽  
pp. 1460135
Author(s):  
CARMEN PAVEL ◽  
FLORIN CONSTANTIN ◽  
COSMIN IOAN SUCIU ◽  
ROXANA BUGOI
Keyword(s):  
Computed Tomography ◽  
Cultural Heritage ◽  
Nuclear Physics ◽  
Structural Information ◽  
Ct Scans ◽  
Visual Examination ◽  
X Ray ◽  
X Ray Computed ◽  
Internal Configuration ◽  
Non Destructive

X-ray Computed Tomography (CT) is a powerful non-destructive technique that can yield interesting structural information not discernible through visual examination only. This paper presents the results of the CT scans of four objects belonging to the Romanian cultural heritage attributed to the Vinča, Cucuteni and Cruceni-Belegiš cultures. The study was performed with an X-ray tomographic device developed at the Department for Applied Nuclear Physics from Horia Hulubei National Institute for Nuclear Physics and Engineering in Măgurele, Romania. This apparatus was specially designed for archaeometric studies of low-Z artifacts: ceramic, wood, bone. The tomographic investigations revealed the internal configuration of the objects and provided information about the degree to which the previous manipulations affected the archaeological items. Based on the X-ray images resulting from the CT scans, hints about the techniques used in the manufacturing of the artifacts were obtained, as well as some indications useful for conservation/restoration purposes.

scholarly journals Gold Exploration in Two and Three Dimensions: Improved and Correlative Insights from Microscopy and X-Ray Computed Tomography

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 476
Author(s):  
Joshua Chisambi ◽  
Bjorn von der Heyden ◽  
Muofhe Tshibalanganda ◽  
Stephan Le Roux
Keyword(s):  
Computed Tomography ◽  
Spatial Distribution ◽  
Gold Mineralization ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Low Grade ◽  
X Ray ◽  
3D Space ◽  
X Ray Computed ◽  
2D And 3D

In this contribution, we highlight a correlative approach in which three-dimensional structural/positional data are combined with two dimensional chemical and mineralogical data to understand a complex orogenic gold mineralization system; we use the Kirk Range (southern Malawi) as a case study. Three dimensional structures and semi-quantitative mineral distributions were evaluated using X-ray Computed Tomography (XCT) and this was augmented with textural, mineralogical and chemical imaging using Scanning Electron Microscopy (SEM) and optical microscopy as well as fire assay. Our results detail the utility of the correlative approach both for quantifying gold concentrations in core samples (which is often nuggety and may thus be misrepresented by quarter- or half-core assays), and for understanding the spatial distribution of gold and associated structures and microstructures in 3D space. This approach overlays complementary datasets from 2D and 3D analytical protocols, thereby allowing a better and more comprehensive understanding on the distribution and structures controlling gold mineralization. Combining 3D XCT analyses with conventional 2D microscopies derive the full value out of a given exploration drilling program and it provides an excellent tool for understanding gold mineralization. Understanding the spatial distribution of gold and associated structures and microstructures in 3D space holds vast potential for exploration practitioners, especially if the correlative approach can be automated and if the resultant spatially-constrained microstructural information can be fed directly into commercially available geological modelling software. The extra layers of information provided by using correlative 2D and 3D microscopies offer an exciting new tool to enhance and optimize mineral exploration workflows, given that modern exploration efforts are targeting increasingly complex and low-grade ore deposits.

scholarly journals Three-dimensional visualisation of the internal anatomy of the sparrowhawk (Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3039 ◽  
Author(s):  
Fernanda Bribiesca-Contreras ◽  
William I. Sellers
Keyword(s):  
Computed Tomography ◽  
3D Model ◽  
Three Dimensional ◽  
Biomechanical Analysis ◽  
X Ray ◽  
Accipiter Nisus ◽  
Contrast Enhanced ◽  
Muscle Geometry ◽  
The Individual ◽  
Non Destructive

BackgroundGross dissection is a widespread method for studying animal anatomy, despite being highly destructive and time-consuming. X-ray computed tomography (CT) has been shown to be a non-destructive alternative for studying anatomical structures. However, in the past it has been limited to only being able to visualise mineralised tissues. In recent years, morphologists have started to use traditional X-ray contrast agents to allow the visualisation of soft tissue elements in the CT context. The aim of this project is to assess the ability of contrast-enhanced micro-CT (μCT) to construct a three-dimensional (3D) model of the musculoskeletal system of the bird wing and to quantify muscle geometry and any systematic changes due to shrinkage. We expect that this reconstruction can be used as an anatomical guide to the sparrowhawk wing musculature and form the basis of further biomechanical analysis of flight.MethodsA 3% iodine-buffered formalin solution with a 25-day staining period was used to visualise the wing myology of the sparrowhawk (Accipiter nisus). μCT scans of the wing were taken over the staining period until full penetration of the forelimb musculature by iodine was reached. A 3D model was reconstructed by manually segmenting out the individual elements of the avian wing using 3D visualisation software.ResultsDifferent patterns of contrast were observed over the duration of the staining treatment with the best results occurring after 25 days of staining. Staining made it possible to visualise and identify different elements of the soft tissue of the wing. Finally, a 3D reconstruction of the musculoskeletal system of the sparrowhawk wing is presented and numerical data of muscle geometry is compared to values obtained by dissection.DiscussionContrast-enhanced μCT allows the visualisation and identification of the wing myology of birds, including the smaller muscles in the hand, and provides a non-destructive way for quantifying muscle volume with an accuracy of 96.2%. By combining contrast-enhanced μCT with 3D visualisation techniques, it is possible to study the individual muscles of the forelimb in their original position and 3D design, which can be the basis of further biomechanical analysis. Because the stain can be washed out post analysis, this technique provides a means of obtaining quantitative muscle data from museum specimens non-destructively.

scholarly journals Selection and evaluation of spherical acquisition trajectories for industrial computed tomography

2021 ◽  
Vol 477 (2250) ◽  
pp. 20210192
Author(s):  
Fabian Bauer ◽  
Matthias Goldammer ◽  
Christian U. Grosse
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Optimization Method ◽  
Three Dimensions ◽  
Trajectory Design ◽  
Destructive Testing ◽  
Monte Carlo Algorithms ◽  
Quantitative Metrics ◽  
Industrial Computed Tomography ◽  
Non Destructive

In conventional industrial computed tomography, the source–detector system rotates in equiangular steps in-plane relative to the part of investigation. While being by far the most frequently used acquisition trajectory today, this method has several drawbacks like the formation of cone beam artefacts or limited usability in case of geometrical restrictions. In such cases, the usage of alternative spherical trajectories can be beneficial to improve image quality and defect visibility. While investigations have been performed to relate the influence of the trajectory choice in the typical metrological case of a high number of available projections, so far barely any work has been done for the case of few source–detector poses, which is more relevant in the field of non-destructive testing. In this work, we provide an overview of quantitative metrics that can be used to assess the image quality of reconstructed computed tomography volumes, discuss their advantages and drawbacks and propose a framework to investigate the performance of several non-standard trajectories with respect to previously defined regions of interest. Inspired by pseudorandom sampling methods for Monte–Carlo-algorithms, we also suggest an entirely new trajectory design, the low-discrepancy spherical trajectory, which extends the concept of equiangular planar trajectories into three dimensions and can be used for benchmarking and comparison with other spherical trajectories. Last, we use an optimization method to calculate task-specific acquisition trajectories and relate their performance to other spherical designs.

scholarly journals Sagittal discrepancies of the jaw in a Bangladeshi cohort: three-dimensional computed tomography analysis

2019 ◽  
Vol 47 (8) ◽  
pp. 3613-3622
Author(s):  
Mushrath Islam ◽  
Ayman Hameed Uraibi ◽  
Arkan Al Azzawi ◽  
Mohammad Khursheed Alam ◽  
Asilah Yusof
Keyword(s):  
Computed Tomography ◽  
3D Imaging ◽  
Three Dimensional ◽  
Ct Scans ◽  
Radiology Department ◽  
Men And Women ◽  
Essential Step ◽  
Beta Angle ◽  
Spss Software ◽  
Tomography Analysis

Objectives In orthodontic diagnosis and treatment planning, the assessment of skeletal jaw relationships is an essential step. This study aimed to evaluate skeletal jaw relationships in a Bangladeshi cohort by using traditional (ANB angle and Wits appraisal) and newly described (Beta angle, W angle, and Yen angle) sagittal measurements in three-dimensional (3D) computed tomography (CT). Methods The radiology department conducted CT scans of Bangladeshi patients. Mimics 3D imaging software (Materialise) was used to process the CT images and evaluate 3D sagittal measurements. SPSS software (IBM) was used to assess significant differences in the data at a confidence level of 5%. Independent-samples t-tests were used to evaluate sexual dimorphism for the measured values. Results In total, 85 men and 32 women were included in this study. All measurements were equivalent to the existing standards. There were no significant differences in the acquired values between men and women. Measurements were consistent with Class I normal classification. Conclusions This study established 3D CT standards for ANB, Wits appraisal, Beta angle, W angle, and Yen angle in Bangladeshi patients.

Planning Mandibular Distraction: Preliminary Report

1995 ◽  
Vol 32 (1) ◽  
pp. 71-76 ◽  
Author(s):  
H. Wolfgang Losken ◽  
Gary T. Patterson ◽  
Spiros A. Lazarou ◽  
Timothy Whitney
Keyword(s):  
Computed Tomography ◽  
Preliminary Report ◽  
Three Dimensional ◽  
Ct Scans ◽  
Obtuse Angle ◽  
3D Ct ◽  
Mandibular Angle ◽  
Mandibular Distraction ◽  
Different Ages ◽  
Horizontal Ramus

Normal lengths of the vertical ramus, body, and angle of the mandible at different ages are presented. Before mandibular distraction is embarked on, the extent of the deficiency of the mandible is assessed. The length of the vertical ramus and body are measured on cephalometric radiographs or three-dimensional computed tomography (3D CT) scans. Deficiency of the length of the mandible is calculated. The position of the pin placement angle (from the horizontal ramus) is calculated by means of the following formula: 180 degrees minus mandibular angle times vertical ramus deficiency divided by total deficiency. Placing the pins correctly will result in correction of the vertical ramus and body deficiency of the mandible and the excessively obtuse angle of the mandible will become more acute.

Sign in / Sign up

Export Citation Format

Share Document