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.

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.

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.

Adaptive Fuzzy Segmentation of Tumors in Three-Dimensional Computed Tomography (CT) Image Data

2007 ◽  
Author(s):  
Jung Leng Foo ◽  
Go Miyano ◽  
Thom Lobe ◽  
Eliot Winer
Keyword(s):  
Computed Tomography ◽  
Fuzzy Inference ◽  
Three Dimensional ◽  
Fuzzy Rule ◽  
Region Of Interest ◽  
Image Data ◽  
Ct Image ◽  
Inference System ◽  
Ct Data ◽  
Fuzzy Segmentation

The continuing advancement of computed tomography (CT) technology has improved the analysis and visualization of tumor data. As imaging technology continues to accommodate the need for high quality medical image data, this encourages the research for more efficient ways of extracting crucial information from these vast amounts of data. A new segmentation method using a fuzzy rule based system to segment tumors in a three-dimensional CT data has been developed. To initialize the segmentation process, the user selects the region of interest (ROI) within the tumor in the first image of the CT study set. Using the ROI’s spatial and intensity properties, fuzzy inputs are generated for use in the fuzzy inference system. From a set of predefined fuzzy rules, the system generates a defuzzified output for every pixel in terms of similarity to the object. Pixels with the highest similarity values are selected to be the tumor. This process is repeated for every subsequent slice in the CT set, and the segmented region from the previous slice is used as the ROI for the current slice. This creates a propagation of information from the previous slices, to be used to segment the current slice. The membership functions used during the fuzzification and defuzzification processes are adaptive to the changes in the size and pixel intensities of the current ROI. The proposed method is highly customizable to suit different needs of a user, requiring information from only a single two-dimensional image. Implementing the fuzzy segmentation on two distinct CT sets, the fuzzy segmentation algorithm was able to successfully extract the tumor from the CT image data. Based on the results statistics, the developed segmentation technique is approximately 96% accurate when compared to the results of manual segmentations performed.

scholarly journals 3D immersive visualization of micro-computed tomography and XRD texture datasets

2019 ◽  
Vol 34 (2) ◽  
pp. 97-102
Author(s):  
M. A. Rodriguez ◽  
T. T. Amon ◽  
J. J. M. Griego ◽  
H. Brown-Shaklee ◽  
N. Green
Keyword(s):  
Computed Tomography ◽  
Texture Analysis ◽  
Mechanical Strain ◽  
Three Dimensional ◽  
Multidimensional Analysis ◽  
Micro Computed Tomography ◽  
X Ray ◽  
3D Data ◽  
Pole Figures ◽  
Ct Data

Advancements in computer technology have enabled three-dimensional (3D) reconstruction, data-stitching, and manipulation of 3D data obtained on X-ray imaging systems such as micro-computed tomography (μ-CT). Likewise, intuitive evaluation of these 3D datasets can be enhanced by recent advances in virtual reality (VR) hardware and software. Additionally, the generation, viewing, and manipulation of 3D X-ray diffraction datasets, such as pole figures employed for texture analysis, can also benefit from these advanced visualization techniques. We present newly-developed protocols for porting 3D data (as TIFF-stacks) into a Unity gaming software platform so that data may be toured, manipulated, and evaluated within a more-intuitive VR environment through the use of game-like controls and 3D headsets. We demonstrate this capability by rendering μ-CT data of a polymer dogbone test bar at various stages of in situ mechanical strain. An additional experiment is presented showing 3D XRD data collected on an aluminum test block with vias. These 3D XRD data for texture analysis (χ, ϕ, 2θ dimensions) enables the viewer to visually inspect 3D pole figures and detect the presence or absence of in-plane residual macrostrain. These two examples serve to illustrate the benefits of this new methodology for multidimensional analysis.

Three-dimensional reconstruction of the foot from computed tomography scans

1989 ◽  
Vol 79 (8) ◽  
pp. 384-394 ◽  
Author(s):  
BE Hirsch ◽  
JK Udupa ◽  
D Roberts
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Computer Programs ◽  
Three Dimensional Reconstruction ◽  
Articular Surfaces ◽  
Internal Structures ◽  
Computed Tomography Scans ◽  
Dimensional Reconstruction ◽  
New Type

Recently developed computer programs create a new type of image from the sections created in computed tomography. These images look like actual photographs of internal structures. The authors describe the process of three-dimensional reconstruction in nonmathematical terms, and provide examples of its use in imaging the bones of the foot. They demonstrate the technique's ability to resolve small details, and its usefulness in displaying articular surfaces.

scholarly journals Glycoblocks: a schematic three-dimensional representation for glycans and their interactions

2016 ◽  
Vol 73 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Stuart McNicholas ◽  
Jon Agirre
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Stacking Interactions ◽  
Molecular Graphics ◽  
Interacting Protein ◽  
Protein Residues ◽  
Three Dimensional Representation ◽  
Close Range ◽  
Covalently Linked

The close-range interactions provided by covalently linked glycans are essential for the correct folding of glycoproteins and also play a pivotal role in recognition processes. Being able to visualise protein–glycan and glycan–glycan contacts in a clear way is thus of great importance for the understanding of these biological processes. In structural terms, glycosylation sugars glue the protein together via hydrogen bonds, whereas non-covalently bound glycans frequently harness additional stacking interactions. Finding an unobscured molecular view of these multipartite scenarios is usually far from trivial; in addition to the need to show the interacting protein residues, glycans may contain many branched sugars, each composed of more than ten non-H atoms and offering more than three potential bonding partners. With structural glycoscience finally gaining popularity and steadily increasing the deposition rate of three-dimensional structures of glycoproteins, the need for a clear way of depicting these interactions is more pressing than ever. Here a schematic representation, named Glycoblocks, is introduced which combines a simplified bonding-network depiction (covering hydrogen bonds and stacking interactions) with the familiar two-dimensional glycan notation used by the glycobiology community, brought into three dimensions by the CCP4 molecular graphics project (CCP4mg).

scholarly journals BigTop: A Three-Dimensional Virtual Reality tool for GWAS Visualization

2019 ◽  
Author(s):  
Samuel T. Westreich ◽  
Maria Nattestad ◽  
Christopher Meyer
Keyword(s):  
Virtual Reality ◽  
Association Studies ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Gene Location ◽  
P Value ◽  
Genome Wide Association Studies ◽  
Two Dimensional ◽  
Three Dimensional Representation ◽  
Manhattan Plot

AbstractBackgroundGenome-wide association studies (GWAS) are typically visualized using a two-dimensional Manhattan plot, displaying chromosomal location of SNPs along the x-axis and the negative log-10 of their p-value on the y-axis. This traditional plot provides a broad overview of the results, but offers little opportunity for interaction or expansion of specific regions, and is unable to show additional dimensions of the dataset.ResultsWe created BigTop, a visualization framework in virtual reality (VR), designed to render a Manhattan plot in three dimensions, wrapping the graph around the user in a simulated cylindrical room. BigTop uses the z-axis to display minor allele frequency of each SNP, allowing for the identification of allelic variants of genes. BigTop also offers additional interactivity, allowing users to select any individual SNP and receive expanded information, including SNP name, exact values, and gene location, if applicable. BigTop is built in JavaScript using the React and A-Frame frameworks, and can be rendered using commercially available VR headsets or in a two-dimensional web browser such as Google Chrome. Data is read into BigTop in JSON format, and can be provided as either JSON or a tab-separated text file.ConclusionsUsing additional dimensions and interactivity options offered through VR, we provide a new, interactive, three-dimensional representation of the traditional Manhattan plot for displaying and exploring GWAS data.

Preparation of serial sections

1989 ◽  
Vol 4 ◽  
pp. 146-156 ◽  
Author(s):  
Michael R. Sandy
Keyword(s):  
Three Dimensional ◽  
Diamond Wheel ◽  
Three Dimensions ◽  
Serial Sections ◽  
Serial Sectioning ◽  
Permanent Record ◽  
Glass Slides ◽  
Internal Structures ◽  
Abrasive Surface ◽  
Saw Blade

Serial sectioning (also referred to as serial grinding) is used to investigate the internal structures of three-dimensional (rock or fossil). In this process series of sections are ground or cut in sequence through a specimen to reveal its internal structures. The specimen is ground down against an abrasive surface (e.g., abrasive powder on a sheet of steel or a rotating diamond wheel on a lathe) or cut with a saw blade. The details of each section can be recorded by drawing or photography. A permanent record of each surface can be made by taking acetate peels and mounting them in glass slides (Wilson and Palmer, this volume, Chapter 13). Serial section information can be digitized and reconstructed in three-dimensions using computer techniques (Chapman, this volume, Chapter 15).

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.

Sign in / Sign up

Export Citation Format

Share Document