scholarly journals Kidney Segmentation in CT Data Using Hybrid Level-Set Method with Ellipsoidal Shape Constraints

2017 ◽  
Vol 24 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Andrzej Skalski ◽  
Katarzyna Heryan ◽  
Jacek Jakubowski ◽  
Tomasz Drewniak
Keyword(s):  
Computed Tomography ◽  
Level Set ◽  
Renal Cancer ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Energy Functional ◽  
Contour Method ◽  
Ellipsoidal Shape ◽  
Kidney Segmentation

Abstract With development of medical diagnostic and imaging techniques the sparing surgeries are facilitated. Renal cancer is one of examples. In order to minimize the amount of healthy kidney removed during the treatment procedure, it is essential to design a system that provides three-dimensional visualization prior to the surgery. The information about location of crucial structures (e.g. kidney, renal ureter and arteries) and their mutual spatial arrangement should be delivered to the operator. The introduction of such a system meets both the requirements and expectations of oncological surgeons. In this paper, we present one of the most important steps towards building such a system: a new approach to kidney segmentation from Computed Tomography data. The segmentation is based on the Active Contour Method using the Level Set (LS) framework. During the segmentation process the energy functional describing an image is the subject to minimize. The functional proposed in this paper consists of four terms. In contrast to the original approach containing solely the region and boundary terms, the ellipsoidal shape constraint was also introduced. This additional limitation imposed on evolution of the function prevents from leakage to undesired regions. The proposed methodology was tested on 10 Computed Tomography scans from patients diagnosed with renal cancer. The database contained the results of studies performed in several medical centers and on different devices. The average effectiveness of the proposed solution regarding the Dice Coefficient and average Hausdorff distance was equal to 0.862 and 2.37 mm, respectively. Both the qualitative and quantitative evaluations confirm effectiveness of the proposed solution.

Segmentation of Kidneys from Computed Tomography Using 3D Fast GrowCut Algorithm

2013 ◽  
Vol 333-335 ◽  
pp. 1145-1150 ◽  
Author(s):  
Gao Yuan Dai ◽  
Zhi Cheng Li ◽  
Jia Gu ◽  
Lei Wang ◽  
Xing Min Li ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Experimental Results ◽  
Volume Data ◽  
Great Role ◽  
Color Features ◽  
Monotonically Decreasing Function ◽  
Kidney Segmentation ◽  
Ct Volume

This paper proposes a fast GrowCut (FGC) algorithm and applies the new algorithm in three-dimensional (3D)kidney segmentation from computed tomography (CT) volume data. Users could mark the object of interest with different labels in CT slices.FGC propagates the labels using monotonically decreasing function and color features to derive an optimal cut for a given data in space. The color features play a great role in comparing with neighborhood cells. The experimental results clearly demonstrate the superiority of FGC in accuracy and speed.

scholarly journals Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

2016 ◽  
Vol 796 ◽  
pp. 558-587 ◽  
Author(s):  
Ronny Pini ◽  
Nicholas T. Vandehey ◽  
Jennifer Druhan ◽  
James P. O’Neil ◽  
Sally M. Benson
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Tracer Tests ◽  
Spatial Arrangement ◽  
Small Scale ◽  
Local Dispersion ◽  
Advection Dispersion ◽  
Driving Mechanisms ◽  
Positron Emission ◽  
Longitudinal Dispersivity

We report results of an experimental investigation into the effects of small-scale (mm–cm) heterogeneities on solute spreading and mixing in a Berea sandstone core. Pulse-tracer tests have been carried out in the Péclet number regime $Pe=6{-}40$ and are supplemented by a unique combination of two imaging techniques. X-ray computed tomography (CT) is used to quantify subcore-scale heterogeneities in terms of permeability contrasts at a spatial resolution of approximately $10~\text{mm}^{3}$, while [11C] positron emission tomography (PET) is applied to image the spatial and temporal evolution of the full tracer plume non-invasively. To account for both advective spreading and local (Fickian) mixing as driving mechanisms for solute transport, a streamtube model is applied that is based on the one-dimensional advection–dispersion equation. We refer to our modelling approach as semideterministic, because the spatial arrangement of the streamtubes and the corresponding solute travel times are known from the measured rock’s permeability map, which required only small adjustments to match the measured tracer breakthrough curve. The model reproduces the three-dimensional PET measurements accurately by capturing the larger-scale tracer plume deformation as well as subcore-scale mixing, while confirming negligible transverse dispersion over the scale of the experiment. We suggest that the obtained longitudinal dispersivity ($0.10\pm 0.02$  cm) is rock rather than sample specific, because of the ability of the model to decouple subcore-scale permeability heterogeneity effects from those of local dispersion. As such, the approach presented here proves to be very valuable, if not necessary, in the context of reservoir core analyses, because rock samples can rarely be regarded as ‘uniformly heterogeneous’.

scholarly journals Descriptive anatomy of the largest known specimen of Protoichthyosaurus prostaxalis (Reptilia: Ichthyosauria) including computed tomography and digital reconstruction of a three-dimensional skull

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6112 ◽  
Author(s):  
Dean R. Lomax ◽  
Laura B. Porro ◽  
Nigel R. Larkin
Keyword(s):  
Computed Tomography ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Lower Jurassic ◽  
Science Museum ◽  
Three Dimensional Reconstruction ◽  
Digital Reconstruction ◽  
Reconstruction Methods ◽  
Dimensional Reconstruction ◽  
Marine Reptile

Ichthyosaur fossils are abundant in Lower Jurassic sediments with nine genera found in the UK. In this paper, we describe the partial skeleton of a large ichthyosaur from the Lower Jurassic (lower Sinemurian) of Warwickshire, England, which was conserved and rearticulated to form the centrepiece of a new permanent gallery at the Thinktank, Birmingham Science Museum in 2015. The unusual three-dimensional preservation of the specimen permitted computed tomography (CT) scanning of individual braincase elements as well as the entire reassembled skull. This represents one of the first times that medical imaging and three-dimensional reconstruction methods have been applied to a large skull of a marine reptile. Data from these scans provide new anatomical information, such as the presence of branching vascular canals within the premaxilla and dentary, and an undescribed dorsal (quadrate) wing of the pterygoid hidden within matrix. Scanning also revealed areas of the skull that had been modelled in wood, clay and other materials after the specimen’s initial discovery, highlighting the utility of applying advanced imaging techniques to historical specimens. Additionally, the CT data served as the basis for a new three-dimensional reconstruction of the skull, in which minor damage was repaired and the preserved bones digitally rearticulated. Thus, for the first time a digital reconstruction of the skull and mandible of a large marine reptile skull is available. Museum records show the specimen was originally identified as an example of Ichthyosaurus communis but we identify this specimen as Protoichthyosaurus prostaxalis. The specimen features a skull nearly twice as long as any previously described specimen of P. prostaxalis, representing an individual with an estimated total body length between 3.2 and 4 m.

scholarly journals Active Contours Using Additive Local and Global Intensity Fitting Models for Intensity Inhomogeneous Image Segmentation

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Shafiullah Soomro ◽  
Farhan Akram ◽  
Jeong Heon Kim ◽  
Toufique Ahmed Soomro ◽  
Kwang Nam Choi
Keyword(s):  
Level Set ◽  
Active Contours ◽  
Energy Functional ◽  
Contour Method ◽  
Intensity Information ◽  
Additive Formulation ◽  
Active Contour Method ◽  
Local Intensity ◽  
Cv Model ◽  
Level Set Formulation

This paper introduces an improved region based active contour method with a level set formulation. The proposed energy functional integrates both local and global intensity fitting terms in an additive formulation. Local intensity fitting term influences local force to pull the contour and confine it to object boundaries. In turn, the global intensity fitting term drives the movement of contour at a distance from the object boundaries. The global intensity term is based on the global division algorithm, which can better capture intensity information of an image than Chan-Vese (CV) model. Both local and global terms are mutually assimilated to construct an energy function based on a level set formulation to segment images with intensity inhomogeneity. Experimental results show that the proposed method performs better both qualitatively and quantitatively compared to other state-of-the-art-methods.

Complementary Imaging Techniques for Charcoal Examination and Identification

IAWA Journal ◽  
2013 ◽  
Vol 34 (2) ◽  
pp. 147-168 ◽  
Author(s):  
Wannes Hubau ◽  
Jan Van den Bulcke ◽  
Peter Kitin ◽  
Loes Brabant ◽  
Joris Van Acker ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Volumetric Imaging ◽  
Anatomical Features ◽  
X Ray ◽  
X Ray Computed ◽  
Relative Potential ◽  
High Level ◽  
The Tropics

Identification of ancient charcoal fragments is a valuable tool in reconstructing past environments and determining natural and anthropogenic disturbances, and for understanding past cultures and societies. Although in Europe such studies are fairly straightforward, utilising charcoal records from the tropics is more complicated due to the species-richness of the natural vegetation. Comprehensive databases have greatly aided identification but often identification of charcoalified woods from the tropics relies on minute anatomical features that can be difficult to observe due to preservation or lack of abundance.This article illustrates the relative potential of four imaging techniques and discusses how they can provide optimal visualisation of charcoal anatomy, such that specific difficulties encountered during charcoal examination can be evaluated and fine anatomical characters can be observed enabling high-level identification of charcoal (and wood) taxa. Specifically reflected Light Microscopy is often used to quickly group large numbers of charcoal fragments into charcoal types. Scanning Electron Microscopy and High-Throughput X-ray Computed Tomography are employed to observe fine anatomical detail. More recently X-ray Computed Tomography at very high resolution has proved successful for imaging hidden or ‘veiled’ anatomical features that cannot be detected on exposed surfaces but need three-dimensional volumetric imaging.

scholarly journals A Technique for Quantifying Wrist Motion Using Four-Dimensional Computed Tomography: Approach and Validation

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Kristin Zhao ◽  
Ryan Breighner ◽  
David Holmes ◽  
Shuai Leng ◽  
Cynthia McCollough ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Ligament Injury ◽  
Imaging Biomarkers ◽  
Clinical Implementation ◽  
Position Information ◽  
Wrist Motion

Accurate quantification of subtle wrist motion changes resulting from ligament injuries is crucial for diagnosis and prescription of the most effective interventions for preventing progression to osteoarthritis. Current imaging techniques are unable to detect injuries reliably and are static in nature, thereby capturing bone position information rather than motion which is indicative of ligament injury. A recently developed technique, 4D (three dimensions + time) computed tomography (CT) enables three-dimensional volume sequences to be obtained during wrist motion. The next step in successful clinical implementation of the tool is quantification and validation of imaging biomarkers obtained from the four-dimensional computed tomography (4DCT) image sequences. Measures of bone motion and joint proximities are obtained by: segmenting bone volumes in each frame of the dynamic sequence, registering their positions relative to a known static posture, and generating surface polygonal meshes from which minimum distance (proximity) measures can be quantified. Method accuracy was assessed during in vitro simulated wrist movement by comparing a fiducial bead-based determination of bone orientation to a bone-based approach. The reported errors for the 4DCT technique were: 0.00–0.68 deg in rotation; 0.02–0.30 mm in translation. Results are on the order of the reported accuracy of other image-based kinematic techniques.

scholarly journals The validation of a novel index assessing canine impactions

2013 ◽  
Vol 07 (04) ◽  
pp. 399-404 ◽  
Author(s):  
Chung How Kau ◽  
John J. Lee ◽  
Nada M. Souccar
Keyword(s):  
Computed Tomography ◽  
Clinical Practice ◽  
Social Science ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Cone Beam ◽  
The Novel ◽  
Kappa Score ◽  
The Social ◽  
Level Of Agreement

ABSTRACTAim: The aims of this study are to determine the level of agreement of orthodontists in the management of impacted maxillary canines and test this agreement against a novel three-dimensional (3D) classification system (KPG index). Materials and Methods: A total of 55 clinicians evaluated 18 impacted maxillary canines of variable complexity. For each case, they used a panoramic and maxillary standard occlusal radiographs derived from cone beam computed tomography. Clinicians were asked to rate each canine in one of four categories: Easy, moderate, difficult and extremely difficult. The obtained scores were tabulated and compared with a novel index rating the difficulty of canine impactions. Statistical package for the social science 17.0 was used to analyze the datasets and the kappa score was used to determine levels of agreement. Results: The kappa score was 0.437. The levels of agreement in the novel index and the clinician scoring were as follows; easy (62.73%), moderate (60.59%), difficult (61.80%) and extremely difficult (72.72%). Conclusions: The following conclusions can be drawn from this study: (1) Clinicians are variable in rating the complexity of canine impactions using traditional radiographic techniques. (2) The novel index shows a good level of agreement with the clinician′s perception of difficulty in orthodontic cases especially at the extremes of the spectrum. (3) This index based on the 3D coordinates of the spatial arrangement of the canine may be incorporated into clinical practice.

Application of X-ray computed tomography to soil science: A literature review

2008 ◽  
Vol 88 (1) ◽  
pp. 1-19 ◽  
Author(s):  
I A Taina ◽  
R J Heck ◽  
T R Elliot
Keyword(s):  
Computed Tomography ◽  
Spatial Configuration ◽  
Energy Levels ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Invasive Technique ◽  
Reconstruction Algorithms ◽  
Biotic Factor ◽  
X Ray ◽  
X Ray Computed

The study of the spatial configuration of soil, in its complexity, requires an understanding of the interrelations and interactions between the diverse soil constituents, at various levels of organization. Investigations of the spatial arrangement of the mineral and organic components of soil have benefited from the development of techniques for structural analysis. X-ray computed tomography (CT) is a non-destructive and non-invasive technique that has been successfully used for three-dimensional (3D) examination of soil. Valuable information has been obtained by the application of CT for the description and quantitative measurements of soil structure elements, especially of soil pores and pore network features. In many studies, X-ray CT has been used to investigate the hydro-physical characteristics of the soil, in a functional and temporal manner. A dynamic approach has also been utilized in the evaluation of the biotic factor influence on soil. The analysis of soil solid phases, by X-ray CT, has been challenging due to the similar X-ray attenuation of different solid constituents. However, the use of multiple X-ray energy levels has facilitated the discrimination of minerals in soil. The aim of this review and synthesis is to offer a perspective on the major issues related to application of the technique, general attempted solutions and possible directions in the utilization of X-ray CT in soil research. Relevant scanning parameters, procedures for CT image reconstruction, algorithms for the quantification of soil characteristics and results are presented for each type of application. Key words: X-ray computed tomography, energy level, spatial resolution, segmentation, soil mineral and organic constituents, soil physical and hydro-physical properties, soil biota

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