Science.gov

Sample records for population segments volume

  1. Economic Analysis. Volume I. Course Segments 4-15.

    ERIC Educational Resources Information Center

    Sterling Inst., Washington, DC. Educational Technology Center.

    The first volume of the United States Naval Academy's individualized instruction course in economic analysis covers segments 4-15 of the course. Topics in this introduction include the nature and methods of economics, production possibilities, demand, supply and equilibrium, and the concept of the circular flow. Other segments of the course, the…

  2. Bioimpedance Measurement of Segmental Fluid Volumes and Hemodynamics

    NASA Technical Reports Server (NTRS)

    Montgomery, Leslie D.; Wu, Yi-Chang; Ku, Yu-Tsuan E.; Gerth, Wayne A.; DeVincenzi, D. (Technical Monitor)

    2000-01-01

    Bioimpedance has become a useful tool to measure changes in body fluid compartment volumes. An Electrical Impedance Spectroscopic (EIS) system is described that extends the capabilities of conventional fixed frequency impedance plethysmographic (IPG) methods to allow examination of the redistribution of fluids between the intracellular and extracellular compartments of body segments. The combination of EIS and IPG techniques was evaluated in the human calf, thigh, and torso segments of eight healthy men during 90 minutes of six degree head-down tilt (HDT). After 90 minutes HDT the calf and thigh segments significantly (P < 0.05) lost conductive volume (eight and four percent, respectively) while the torso significantly (P < 0.05) gained volume (approximately three percent). Hemodynamic responses calculated from pulsatile IPG data also showed a segmental pattern consistent with vascular fluid loss from the lower extremities and vascular engorgement in the torso. Lumped-parameter equivalent circuit analyses of EIS data for the calf and thigh indicated that the overall volume decreases in these segments arose from reduced extracellular volume that was not completely balanced by increased intracellular volume. The combined use of IPG and EIS techniques enables noninvasive tracking of multi-segment volumetric and hemodynamic responses to environmental and physiological stresses.

  3. Uterine fibroid segmentation and volume measurement on MRI

    NASA Astrophysics Data System (ADS)

    Yao, Jianhua; Chen, David; Lu, Wenzhu; Premkumar, Ahalya

    2006-03-01

    Uterine leiomyomas are the most common pelvic tumors in females. The efficacy of medical treatment is gauged by shrinkage of the size of these tumors. In this paper, we present a method to robustly segment the fibroids on MRI and accurately measure the 3D volume. Our method is based on a combination of fast marching level set and Laplacian level set. With a seed point placed inside the fibroid region, a fast marching level set is first employed to obtain a rough segmentation, followed by a Laplacian level set to refine the segmentation. We devised a scheme to automatically determine the parameters for the level set function and the sigmoid function based on pixel statistics around the seed point. The segmentation is conducted on three concurrent views (axial, coronal and sagittal), and a combined volume measurement is computed to obtain a more reliable measurement. We carried out extensive tests on 13 patients, 25 MRI studies and 133 fibroids. The segmentation result was validated against manual segmentation defined by experts. The average segmentation sensitivity (true positive fraction) among all fibroids was 84.6%, and the average segmentation specificity (1-false positive fraction) was 84.3%.

  4. 3D visualization for medical volume segmentation validation

    NASA Astrophysics Data System (ADS)

    Eldeib, Ayman M.

    2002-05-01

    This paper presents a 3-D visualization tool that manipulates and/or enhances by user input the segmented targets and other organs. A 3-D visualization tool is developed to create a precise and realistic 3-D model from CT/MR data set for manipulation in 3-D and permitting physician or planner to look through, around, and inside the various structures. The 3-D visualization tool is designed to assist and to evaluate the segmentation process. It can control the transparency of each 3-D object. It displays in one view a 2-D slice (axial, coronal, and/or sagittal)within a 3-D model of the segmented tumor or structures. This helps the radiotherapist or the operator to evaluate the adequacy of the generated target compared to the original 2-D slices. The graphical interface enables the operator to easily select a specific 2-D slice of the 3-D volume data set. The operator is enabled to manually override and adjust the automated segmentation results. After correction, the operator can see the 3-D model again and go back and forth till satisfactory segmentation is obtained. The novelty of this research work is in using state-of-the-art of image processing and 3-D visualization techniques to facilitate a process of a medical volume segmentation validation and assure the accuracy of the volume measurement of the structure of interest.

  5. Three-dimensional CT image segmentation by volume growing

    NASA Astrophysics Data System (ADS)

    Zhu, Dongping; Conners, Richard W.; Araman, Philip A.

    1991-11-01

    The research reported in this paper is aimed at locating, identifying, and quantifying internal (anatomical or physiological) structures, by 3-D image segmentation. Computerized tomography (CT) images of an object are first processed on a slice-by-slice basis, generating a stack of image slices that have been smoothed and pre-segmented. The image smoothing operation is executed by a spatially adaptive filter, and the 2-D pre-segmentation is achieved by a thresholding process whereby each individual pixel in the input image space is consistently assigned a label, according to its CT number, i.e., the gray-level value. Given a sequence of pre-segmented images as 3-D input scene (a stack of image slices), the spatial connectivity that exists among neighboring image pixels is utilized in a volume growing process which generates a number of well-defined volumetric regions or image solides, each representing an individual anatomical or physiological structure in the input scene. The 3-D segmentation is implemented using a volume growing process so that the aspect of pixel spatial connectivity is incorporated into the image segmentation procedure. To initialize the volume growing process for each volumetric region in the input 3-D scene, a seed location for a region is defined and loaded into a queue data structure called seed queue. The volume growing process consists of a set of procedures that perform different operations on the volumetric data of a CT image sequence. Examples of experiment of the described system with CT image data of several hardwood logs are given to demonstrate usefulness and flexibility of this approach. This allows solutions to industrial web inspection, as well as to several problems in medical image analysis where low-level image segmentation plays an important role toward successful image interpretation tasks.

  6. Combining population and patient-specific characteristics for prostate segmentation on 3D CT images

    NASA Astrophysics Data System (ADS)

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-03-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy.

  7. Combining Population and Patient-Specific Characteristics for Prostate Segmentation on 3D CT Images

    PubMed Central

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-01-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy. PMID:27660382

  8. Fast global interactive volume segmentation with regional supervoxel descriptors

    NASA Astrophysics Data System (ADS)

    Luengo, Imanol; Basham, Mark; French, Andrew P.

    2016-03-01

    In this paper we propose a novel approach towards fast multi-class volume segmentation that exploits supervoxels in order to reduce complexity, time and memory requirements. Current methods for biomedical image segmentation typically require either complex mathematical models with slow convergence, or expensive-to-calculate image features, which makes them non-feasible for large volumes with many objects (tens to hundreds) of different classes, as is typical in modern medical and biological datasets. Recently, graphical models such as Markov Random Fields (MRF) or Conditional Random Fields (CRF) are having a huge impact in different computer vision areas (e.g. image parsing, object detection, object recognition) as they provide global regularization for multiclass problems over an energy minimization framework. These models have yet to find impact in biomedical imaging due to complexities in training and slow inference in 3D images due to the very large number of voxels. Here, we define an interactive segmentation approach over a supervoxel space by first defining novel, robust and fast regional descriptors for supervoxels. Then, a hierarchical segmentation approach is adopted by training Contextual Extremely Random Forests in a user-defined label hierarchy where the classification output of the previous layer is used as additional features to train a new classifier to refine more detailed label information. This hierarchical model yields final class likelihoods for supervoxels which are finally refined by a MRF model for 3D segmentation. Results demonstrate the effectiveness on a challenging cryo-soft X-ray tomography dataset by segmenting cell areas with only a few user scribbles as the input for our algorithm. Further results demonstrate the effectiveness of our method to fully extract different organelles from the cell volume with another few seconds of user interaction.

  9. Performance benchmarking of liver CT image segmentation and volume estimation

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Zhou, Jiayin; Tian, Qi; Liu, Jimmy J.; Qi, Yingyi; Leow, Wee Kheng; Han, Thazin; Wang, Shih-chang

    2008-03-01

    In recent years more and more computer aided diagnosis (CAD) systems are being used routinely in hospitals. Image-based knowledge discovery plays important roles in many CAD applications, which have great potential to be integrated into the next-generation picture archiving and communication systems (PACS). Robust medical image segmentation tools are essentials for such discovery in many CAD applications. In this paper we present a platform with necessary tools for performance benchmarking for algorithms of liver segmentation and volume estimation used for liver transplantation planning. It includes an abdominal computer tomography (CT) image database (DB), annotation tools, a ground truth DB, and performance measure protocols. The proposed architecture is generic and can be used for other organs and imaging modalities. In the current study, approximately 70 sets of abdominal CT images with normal livers have been collected and a user-friendly annotation tool is developed to generate ground truth data for a variety of organs, including 2D contours of liver, two kidneys, spleen, aorta and spinal canal. Abdominal organ segmentation algorithms using 2D atlases and 3D probabilistic atlases can be evaluated on the platform. Preliminary benchmark results from the liver segmentation algorithms which make use of statistical knowledge extracted from the abdominal CT image DB are also reported. We target to increase the CT scans to about 300 sets in the near future and plan to make the DBs built available to medical imaging research community for performance benchmarking of liver segmentation algorithms.

  10. Procedures for formation of composite samples from segmented populations

    USGS Publications Warehouse

    Fabrizio, Mary C.; Frank, Anthony M.; Savino, Jacqueline F.

    1995-01-01

    We used a simulation approach to investigate the implication of two methods of forming composite samples to characterize segmented populations. We illustrate the case where the weight of individual segments varies randomly, a situation common with fish samples. Composite samples from segments such as whole fish or muscle tissue should be formed by homogenizing each segment separately and combining equal-sized portions randomly drawn from each homogenate. This approach permits unbiased estimation of the mean concentration per fish. Estimates of mean contaminant concentration varied little with variation in the number of composite samples analyzed or with composite size (number of segments in a composite sample). However, for a fixed number of composite samples, the precision of the variance estimate increases as composite size increased. In addition, for a fixed number of composites, the estimate of the variance stabilized as more segments were included in the composite samples. Estimates of the variance among fish or other population segments can be recovered using appropriate compositing procedures and specially-designed studies.

  11. Using population segmentation to inform local obesity strategy in England.

    PubMed

    Wills, Jane; Crichton, Nicola; Lorenc, Ava; Kelly, Muireann

    2015-09-01

    Little is known about the views of obese people and how best to meet their needs. Amongst London boroughs Barking and Dagenham has the highest prevalence of adult obesity at 28.7%; the lowest level of healthy eating and of physical activity; and is the 22nd most deprived area of England. The study aimed to gain insight into the attitudes, motivations and priorities of people who are obese or overweight to inform the social marketing of an obesity strategy. Two hundred and ten obese or overweight adults were recruited through visual identification in public thoroughfares to attempt to recruit those seldom seen in primary care. One hundred and eighty-one street-intercept and 52 in-depth interviews were conducted. Thematic analysis was followed by psychographic segmentation. Eleven population segments were identified based on their readiness to change, the value accorded to tackling obesity, identified enabling factors and barriers to weight management and perceived self-efficacy. This population showed considerable variation in its readiness to change and perceived control over obesity but considerable similarity in the exchange value they attributed to tackling their obesity. Even within a relatively homogenous socio-demographic community, there needs to be a range of interventions and messages tailored for different population segments that vary in their readiness to change and confidence about tackling obesity. The dominant emphasis of policy and practice on the health consequences of obesity does not reflect the priorities of this obese population for whom the exchange value of addressing obesity was daily functioning especially in relation to family life. PMID:24504360

  12. Using population segmentation to inform local obesity strategy in England.

    PubMed

    Wills, Jane; Crichton, Nicola; Lorenc, Ava; Kelly, Muireann

    2015-09-01

    Little is known about the views of obese people and how best to meet their needs. Amongst London boroughs Barking and Dagenham has the highest prevalence of adult obesity at 28.7%; the lowest level of healthy eating and of physical activity; and is the 22nd most deprived area of England. The study aimed to gain insight into the attitudes, motivations and priorities of people who are obese or overweight to inform the social marketing of an obesity strategy. Two hundred and ten obese or overweight adults were recruited through visual identification in public thoroughfares to attempt to recruit those seldom seen in primary care. One hundred and eighty-one street-intercept and 52 in-depth interviews were conducted. Thematic analysis was followed by psychographic segmentation. Eleven population segments were identified based on their readiness to change, the value accorded to tackling obesity, identified enabling factors and barriers to weight management and perceived self-efficacy. This population showed considerable variation in its readiness to change and perceived control over obesity but considerable similarity in the exchange value they attributed to tackling their obesity. Even within a relatively homogenous socio-demographic community, there needs to be a range of interventions and messages tailored for different population segments that vary in their readiness to change and confidence about tackling obesity. The dominant emphasis of policy and practice on the health consequences of obesity does not reflect the priorities of this obese population for whom the exchange value of addressing obesity was daily functioning especially in relation to family life.

  13. Volume Averaging of Spectral-Domain Optical Coherence Tomography Impacts Retinal Segmentation in Children

    PubMed Central

    Trimboli-Heidler, Carmelina; Vogt, Kelly; Avery, Robert A.

    2016-01-01

    Purpose To determine the influence of volume averaging on retinal layer thickness measures acquired with spectral-domain optical coherence tomography (SD-OCT) in children. Methods Macular SD-OCT images were acquired using three different volume settings (i.e., 1, 3, and 9 volumes) in children enrolled in a prospective OCT study. Total retinal thickness and five inner layers were measured around an Early Treatment Diabetic Retinopathy Scale (ETDRS) grid using beta version automated segmentation software for the Spectralis. The magnitude of manual segmentation required to correct the automated segmentation was classified as either minor (<12 lines adjusted), moderate (>12 and <25 lines adjusted), severe (>26 and <48 lines adjusted), or fail (>48 lines adjusted or could not adjust due to poor image quality). The frequency of each edit classification was assessed for each volume setting. Thickness, paired difference, and 95% limits of agreement of each anatomic quadrant were compared across volume density. Results Seventy-five subjects (median age 11.8 years, range 4.3–18.5 years) contributed 75 eyes. Less than 5% of the 9- and 3-volume scans required more than minor manual segmentation corrections, compared with 71% of 1-volume scans. The inner (3 mm) region demonstrated similar measures across all layers, regardless of volume number. The 1-volume scans demonstrated greater variability of the retinal nerve fiber layer (RNLF) thickness, compared with the other volumes in the outer (6 mm) region. Conclusions In children, volume averaging of SD-OCT acquisitions reduce retinal layer segmentation errors. Translational Relevance This study highlights the importance of volume averaging when acquiring macula volumes intended for multilayer segmentation. PMID:27570711

  14. Population genetic segmentation of MHC-correlated perfume preferences.

    PubMed

    Hämmerli, A; Schweisgut, C; Kaegi, M

    2012-04-01

    It has become difficult to find a matching perfume. An overwhelming number of 300 new perfumes launch each year, and marketing campaigns target pre-defined groups based on gender, age or income rather than on individual preferences. Recent evidence for a genetic basis of perfume preferences, however, could be the starting point for a novel population genetic approach to better match perfumes with people's preferences. With a total of 116 participants genotyped for alleles of three loci of the major histocompatibility complex (MHC), the aim of this study was to test whether common MHC alleles could be used as genetic markers to segment a given population into preference types. Significant deviations from random expectations for a set of 10 common perfume ingredients indicate how such segmentation could be achieved. In addition, preference patterns of participants confronted with images that contained a sexual communication context significantly differed in their ratings for some of the scents compared with participants confronted with images of perfume bottles. This strongly supports the assumption that genetically correlated perfume preferences evolved in the context of sexual communication. The results are discussed in the light of perfume customization.

  15. Midbrain volume segmentation using active shape models and LBPs

    NASA Astrophysics Data System (ADS)

    Olveres, Jimena; Nava, Rodrigo; Escalante-Ramírez, Boris; Cristóbal, Gabriel; García-Moreno, Carla María.

    2013-09-01

    In recent years, the use of Magnetic Resonance Imaging (MRI) to detect different brain structures such as midbrain, white matter, gray matter, corpus callosum, and cerebellum has increased. This fact together with the evidence that midbrain is associated with Parkinson's disease has led researchers to consider midbrain segmentation as an important issue. Nowadays, Active Shape Models (ASM) are widely used in literature for organ segmentation where the shape is an important discriminant feature. Nevertheless, this approach is based on the assumption that objects of interest are usually located on strong edges. Such a limitation may lead to a final shape far from the actual shape model. This paper proposes a novel method based on the combined use of ASM and Local Binary Patterns for segmenting midbrain. Furthermore, we analyzed several LBP methods and evaluated their performance. The joint-model considers both global and local statistics to improve final adjustments. The results showed that our proposal performs substantially better than the ASM algorithm and provides better segmentation measurements.

  16. Multi-region unstructured volume segmentation using tetrahedron filling

    SciTech Connect

    Willliams, Sean Jamerson; Dillard, Scott E; Thoma, Dan J; Hlawitschka, Mario; Hamann, Bernd

    2010-01-01

    Segmentation is one of the most common operations in image processing, and while there are several solutions already present in the literature, they each have their own benefits and drawbacks that make them well-suited for some types of data and not for others. We focus on the problem of breaking an image into multiple regions in a single segmentation pass, while supporting both voxel and scattered point data. To solve this problem, we begin with a set of potential boundary points and use a Delaunay triangulation to complete the boundaries. We use heuristic- and interaction-driven Voronoi clustering to find reasonable groupings of tetrahedra. Apart from the computation of the Delaunay triangulation, our algorithm has linear time complexity with respect to the number of tetrahedra.

  17. Unsupervised segmentation of cardiac PET transmission images for automatic heart volume extraction.

    PubMed

    Juslin, Anu; Tohka, Jussi

    2006-01-01

    In this study, we propose an automatic method to extract the heart volume from the cardiac positron emission tomography (PET) transmission images. The method combines the automatic 3D segmentation of the transmission image using Markov random fields (MRFs) to surface extraction using deformable models. Deformable models were automatically initialized using the MRFs segmentation result. The extraction of the heart region is needed e.g. in independent component analysis (ICA). The volume of the heart can be used to mask the emission image corresponding to the transmission image, so that only the cardiac region is used for the analysis. The masking restricts the number of independent components and reduces the computation time. In addition, the MRF segmentation result could be used for attenuation correction. The method was tested with 25 patient images. The MRF segmentation results were of good quality in all cases and we were able to extract the heart volume from all the images. PMID:17946020

  18. Quantifying brain tissue volume in multiple sclerosis with automated lesion segmentation and filling.

    PubMed

    Valverde, Sergi; Oliver, Arnau; Roura, Eloy; Pareto, Deborah; Vilanova, Joan C; Ramió-Torrentà, Lluís; Sastre-Garriga, Jaume; Montalban, Xavier; Rovira, Àlex; Lladó, Xavier

    2015-01-01

    Lesion filling has been successfully applied to reduce the effect of hypo-intense T1-w Multiple Sclerosis (MS) lesions on automatic brain tissue segmentation. However, a study of fully automated pipelines incorporating lesion segmentation and lesion filling on tissue volume analysis has not yet been performed. Here, we analyzed the % of error introduced by automating the lesion segmentation and filling processes in the tissue segmentation of 70 clinically isolated syndrome patient images. First of all, images were processed using the LST and SLS toolkits with different pipeline combinations that differed in either automated or manual lesion segmentation, and lesion filling or masking out lesions. Then, images processed following each of the pipelines were segmented into gray matter (GM) and white matter (WM) using SPM8, and compared with the same images where expert lesion annotations were filled before segmentation. Our results showed that fully automated lesion segmentation and filling pipelines reduced significantly the % of error in GM and WM volume on images of MS patients, and performed similarly to the images where expert lesion annotations were masked before segmentation. In all the pipelines, the amount of misclassified lesion voxels was the main cause in the observed error in GM and WM volume. However, the % of error was significantly lower when automatically estimated lesions were filled and not masked before segmentation. These results are relevant and suggest that LST and SLS toolboxes allow the performance of accurate brain tissue volume measurements without any kind of manual intervention, which can be convenient not only in terms of time and economic costs, but also to avoid the inherent intra/inter variability between manual annotations.

  19. Quantifying brain tissue volume in multiple sclerosis with automated lesion segmentation and filling

    PubMed Central

    Valverde, Sergi; Oliver, Arnau; Roura, Eloy; Pareto, Deborah; Vilanova, Joan C.; Ramió-Torrentà, Lluís; Sastre-Garriga, Jaume; Montalban, Xavier; Rovira, Àlex; Lladó, Xavier

    2015-01-01

    Lesion filling has been successfully applied to reduce the effect of hypo-intense T1-w Multiple Sclerosis (MS) lesions on automatic brain tissue segmentation. However, a study of fully automated pipelines incorporating lesion segmentation and lesion filling on tissue volume analysis has not yet been performed. Here, we analyzed the % of error introduced by automating the lesion segmentation and filling processes in the tissue segmentation of 70 clinically isolated syndrome patient images. First of all, images were processed using the LST and SLS toolkits with different pipeline combinations that differed in either automated or manual lesion segmentation, and lesion filling or masking out lesions. Then, images processed following each of the pipelines were segmented into gray matter (GM) and white matter (WM) using SPM8, and compared with the same images where expert lesion annotations were filled before segmentation. Our results showed that fully automated lesion segmentation and filling pipelines reduced significantly the % of error in GM and WM volume on images of MS patients, and performed similarly to the images where expert lesion annotations were masked before segmentation. In all the pipelines, the amount of misclassified lesion voxels was the main cause in the observed error in GM and WM volume. However, the % of error was significantly lower when automatically estimated lesions were filled and not masked before segmentation. These results are relevant and suggest that LST and SLS toolboxes allow the performance of accurate brain tissue volume measurements without any kind of manual intervention, which can be convenient not only in terms of time and economic costs, but also to avoid the inherent intra/inter variability between manual annotations. PMID:26740917

  20. Scintigraphic method for the assessment of intraluminal volume and motility of isolated intestinal segments. [Dogs

    SciTech Connect

    Mitchell, A.; Macey, D.J.; Collin, J.

    1983-07-01

    The isolated in vivo intestinal segment is a popular experimental preparation for the investigation of intestinal function, but its value has been limited because no method has been available for measuring changes in intraluminal volume under experimental conditions. We report a scintigraphic technique for measuring intraluminal volume and assessing intestinal motility. Between 30 and 180 ml, the volume of a 75-cm segment of canine jejunum, perfused with Tc-99m-labeled tin colloid, was found to be proportional to the recorded count rate. This method has been used to monitor the effects of the hormone vasopressin on intestinal function.

  1. LANDSAT-D program. Volume 2: Ground segment

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Raw digital data, as received from the LANDSAT spacecraft, cannot generate images that meet specifications. Radiometric corrections must be made to compensate for aging and for differences in sensitivity among the instrument sensors. Geometric corrections must be made to compensate for off-nadir look angle, and to calculate spacecraft drift from its prescribed path. Corrections must also be made for look-angle jitter caused by vibrations induced by spacecraft equipment. The major components of the LANDSAT ground segment and their functions are discussed.

  2. Amygdalar and hippocampal volume: A comparison between manual segmentation, Freesurfer and VBM.

    PubMed

    Grimm, Oliver; Pohlack, Sebastian; Cacciaglia, Raffaele; Winkelmann, Tobias; Plichta, Michael M; Demirakca, Traute; Flor, Herta

    2015-09-30

    Automated segmentation of the amygdala and the hippocampus is of interest for research looking at large datasets where manual segmentation of T1-weighted magnetic resonance tomography images is less feasible for morphometric analysis. Manual segmentation still remains the gold standard for subcortical structures like the hippocampus and the amygdala. A direct comparison of VBM8 and Freesurfer is rarely done, because VBM8 results are most often used for voxel-based analysis. We used the same region-of-interest (ROI) for Freesurfer and VBM8 to relate automated and manually derived volumes of the amygdala and the hippocampus. We processed a large manually segmented dataset of n=92 independent samples with an automated segmentation strategy (VBM8 vs. Freesurfer Version 5.0). For statistical analysis, we only calculated Pearsons's correlation coefficients, but used methods developed for comparison such as Lin's concordance coefficient. The correlation between automatic and manual segmentation was high for the hippocampus [0.58-0.76] and lower for the amygdala [0.45-0.59]. However, concordance coefficients point to higher concordance for the amygdala [0.46-0.62] instead of the hippocampus [0.06-0.12]. VBM8 and Freesurfer segmentation performed on a comparable level in comparison to manual segmentation. We conclude (1) that correlation alone does not capture systematic differences (e.g. of hippocampal volumes), (2) calculation of ROI volumes with VBM8 gives measurements comparable to Freesurfer V5.0 when using the same ROI and (3) systematic and proportional differences are caused mainly by different definitions of anatomic boundaries and only to a lesser part by different segmentation strategies. This work underscores the importance of using method comparison techniques and demonstrates that even with high correlation coefficients, there can be still large differences in absolute volume. PMID:26057114

  3. High volume production trial of mirror segments for the Thirty Meter Telescope

    NASA Astrophysics Data System (ADS)

    Oota, Tetsuji; Negishi, Mahito; Shinonaga, Hirohiko; Gomi, Akihiko; Tanaka, Yutaka; Akutsu, Kotaro; Otsuka, Itaru; Mochizuki, Shun; Iye, Masanori; Yamashita, Takuya

    2014-07-01

    The Thirty Meter Telescope is a next-generation optical/infrared telescope to be constructed on Mauna Kea, Hawaii toward the end of this decade, as an international project. Its 30 m primary mirror consists of 492 off-axis aspheric segmented mirrors. High volume production of hundreds of segments has started in 2013 based on the contract between National Astronomical Observatory of Japan and Canon Inc.. This paper describes the achievements of the high volume production trials. The Stressed Mirror Figuring technique which is established by Keck Telescope engineers is arranged and adopted. To measure the segment surface figure, a novel stitching algorithm is evaluated by experiment. The integration procedure is checked with prototype segment.

  4. Segmentation propagation for the automated quantification of ventricle volume from serial MRI

    NASA Astrophysics Data System (ADS)

    Linguraru, Marius George; Butman, John A.

    2009-02-01

    Accurate ventricle volume estimates could potentially improve the understanding and diagnosis of communicating hydrocephalus. Postoperative communicating hydrocephalus has been recognized in patients with brain tumors where the changes in ventricle volume can be difficult to identify, particularly over short time intervals. Because of the complex alterations of brain morphology in these patients, the segmentation of brain ventricles is challenging. Our method evaluates ventricle size from serial brain MRI examinations; we (i) combined serial images to increase SNR, (ii) automatically segmented this image to generate a ventricle template using fast marching methods and geodesic active contours, and (iii) propagated the segmentation using deformable registration of the original MRI datasets. By applying this deformation to the ventricle template, serial volume estimates were obtained in a robust manner from routine clinical images (0.93 overlap) and their variation analyzed.

  5. 75 FR 30769 - Endangered and Threatened Species; Proposed Listing of Nine Distinct Population Segments of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... Distinct Population Segments of Loggerhead Sea Turtles as Endangered or Threatened; Extension of Comment... proposed listing of nine distinct population segments of loggerhead sea turtles as endangered or threatened... . Mail: NMFS National Sea Turtle Coordinator, Attn: Loggerhead Proposed Listing Rule, Office of...

  6. Pulmonary airways tree segmentation from CT examinations using adaptive volume of interest

    NASA Astrophysics Data System (ADS)

    Park, Sang Cheol; Kim, Won Pil; Zheng, Bin; Leader, Joseph K.; Pu, Jiantao; Tan, Jun; Gur, David

    2009-02-01

    Airways tree segmentation is an important step in quantitatively assessing the severity of and changes in several lung diseases such as chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis. It can also be used in guiding bronchoscopy. The purpose of this study is to develop an automated scheme for segmenting the airways tree structure depicted on chest CT examinations. After lung volume segmentation, the scheme defines the first cylinder-like volume of interest (VOI) using a series of images depicting the trachea. The scheme then iteratively defines and adds subsequent VOIs using a region growing algorithm combined with adaptively determined thresholds in order to trace possible sections of airways located inside the combined VOI in question. The airway tree segmentation process is automatically terminated after the scheme assesses all defined VOIs in the iteratively assembled VOI list. In this preliminary study, ten CT examinations with 1.25mm section thickness and two different CT image reconstruction kernels ("bone" and "standard") were selected and used to test the proposed airways tree segmentation scheme. The experiment results showed that (1) adopting this approach affectively prevented the scheme from infiltrating into the parenchyma, (2) the proposed method reasonably accurately segmented the airways trees with lower false positive identification rate as compared with other previously reported schemes that are based on 2-D image segmentation and data analyses, and (3) the proposed adaptive, iterative threshold selection method for the region growing step in each identified VOI enables the scheme to segment the airways trees reliably to the 4th generation in this limited dataset with successful segmentation up to the 5th generation in a fraction of the airways tree branches.

  7. Multi-Segment Hemodynamic and Volume Assessment With Impedance Plethysmography: Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Webbon, Bruce W. (Technical Monitor)

    1995-01-01

    Definition of multi-segmental circulatory and volume changes in the human body provides an understanding of the physiologic responses to various aerospace conditions. We have developed instrumentation and testing procedures at NASA Ames Research Center that may be useful in biomedical research and clinical diagnosis. Specialized two, four, and six channel impedance systems will be described that have been used to measure calf, thigh, thoracic, arm, and cerebral hemodynamic and volume changes during various experimental investigations.

  8. Swarm Intelligence Integrated Graph-Cut for Liver Segmentation from 3D-CT Volumes.

    PubMed

    Eapen, Maya; Korah, Reeba; Geetha, G

    2015-01-01

    The segmentation of organs in CT volumes is a prerequisite for diagnosis and treatment planning. In this paper, we focus on liver segmentation from contrast-enhanced abdominal CT volumes, a challenging task due to intensity overlapping, blurred edges, large variability in liver shape, and complex background with cluttered features. The algorithm integrates multidiscriminative cues (i.e., prior domain information, intensity model, and regional characteristics of liver in a graph-cut image segmentation framework). The paper proposes a swarm intelligence inspired edge-adaptive weight function for regulating the energy minimization of the traditional graph-cut model. The model is validated both qualitatively (by clinicians and radiologists) and quantitatively on publically available computed tomography (CT) datasets (MICCAI 2007 liver segmentation challenge, 3D-IRCAD). Quantitative evaluation of segmentation results is performed using liver volume calculations and a mean score of 80.8% and 82.5% on MICCAI and IRCAD dataset, respectively, is obtained. The experimental result illustrates the efficiency and effectiveness of the proposed method. PMID:26689833

  9. Synthesis of intensity gradient and texture information for efficient three-dimensional segmentation of medical volumes

    PubMed Central

    Vantaram, Sreenath Rao; Saber, Eli; Dianat, Sohail A.; Hu, Yang

    2015-01-01

    Abstract. We propose a framework that efficiently employs intensity, gradient, and textural features for three-dimensional (3-D) segmentation of medical (MRI/CT) volumes. Our methodology commences by determining the magnitude of intensity variations across the input volume using a 3-D gradient detection scheme. The resultant gradient volume is utilized in a dynamic volume growing/formation process that is initiated in voxel locations with small gradient magnitudes and is concluded at sites with large gradient magnitudes, yielding a map comprising an initial set of partitions (or subvolumes). This partition map is combined with an entropy-based texture descriptor along with intensity and gradient attributes in a multivariate analysis-based volume merging procedure that fuses subvolumes with similar characteristics to yield a final/refined segmentation output. Additionally, a semiautomated version of the aforestated algorithm that allows a user to interactively segment a desired subvolume of interest as opposed to the entire volume is also discussed. Our approach was tested on several MRI and CT datasets and the results show favorable performance in comparison to the state-of-the-art ITK-SNAP technique. PMID:26158098

  10. Precise segmentation of multiple organs in CT volumes using learning-based approach and information theory.

    PubMed

    Lu, Chao; Zheng, Yefeng; Birkbeck, Neil; Zhang, Jingdan; Kohlberger, Timo; Tietjen, Christian; Boettger, Thomas; Duncan, James S; Zhou, S Kevin

    2012-01-01

    In this paper, we present a novel method by incorporating information theory into the learning-based approach for automatic and accurate pelvic organ segmentation (including the prostate, bladder and rectum). We target 3D CT volumes that are generated using different scanning protocols (e.g., contrast and non-contrast, with and without implant in the prostate, various resolution and position), and the volumes come from largely diverse sources (e.g., diseased in different organs). Three key ingredients are combined to solve this challenging segmentation problem. First, marginal space learning (MSL) is applied to efficiently and effectively localize the multiple organs in the largely diverse CT volumes. Second, learning techniques, steerable features, are applied for robust boundary detection. This enables handling of highly heterogeneous texture pattern. Third, a novel information theoretic scheme is incorporated into the boundary inference process. The incorporation of the Jensen-Shannon divergence further drives the mesh to the best fit of the image, thus improves the segmentation performance. The proposed approach is tested on a challenging dataset containing 188 volumes from diverse sources. Our approach not only produces excellent segmentation accuracy, but also runs about eighty times faster than previous state-of-the-art solutions. The proposed method can be applied to CT images to provide visual guidance to physicians during the computer-aided diagnosis, treatment planning and image-guided radiotherapy to treat cancers in pelvic region.

  11. Precise segmentation of multiple organs in CT volumes using learning-based approach and information theory.

    PubMed

    Lu, Chao; Zheng, Yefeng; Birkbeck, Neil; Zhang, Jingdan; Kohlberger, Timo; Tietjen, Christian; Boettger, Thomas; Duncan, James S; Zhou, S Kevin

    2012-01-01

    In this paper, we present a novel method by incorporating information theory into the learning-based approach for automatic and accurate pelvic organ segmentation (including the prostate, bladder and rectum). We target 3D CT volumes that are generated using different scanning protocols (e.g., contrast and non-contrast, with and without implant in the prostate, various resolution and position), and the volumes come from largely diverse sources (e.g., diseased in different organs). Three key ingredients are combined to solve this challenging segmentation problem. First, marginal space learning (MSL) is applied to efficiently and effectively localize the multiple organs in the largely diverse CT volumes. Second, learning techniques, steerable features, are applied for robust boundary detection. This enables handling of highly heterogeneous texture pattern. Third, a novel information theoretic scheme is incorporated into the boundary inference process. The incorporation of the Jensen-Shannon divergence further drives the mesh to the best fit of the image, thus improves the segmentation performance. The proposed approach is tested on a challenging dataset containing 188 volumes from diverse sources. Our approach not only produces excellent segmentation accuracy, but also runs about eighty times faster than previous state-of-the-art solutions. The proposed method can be applied to CT images to provide visual guidance to physicians during the computer-aided diagnosis, treatment planning and image-guided radiotherapy to treat cancers in pelvic region. PMID:23286081

  12. Fully automated segmentation of oncological PET volumes using a combined multiscale and statistical model

    SciTech Connect

    Montgomery, David W. G.; Amira, Abbes; Zaidi, Habib

    2007-02-15

    The widespread application of positron emission tomography (PET) in clinical oncology has driven this imaging technology into a number of new research and clinical arenas. Increasing numbers of patient scans have led to an urgent need for efficient data handling and the development of new image analysis techniques to aid clinicians in the diagnosis of disease and planning of treatment. Automatic quantitative assessment of metabolic PET data is attractive and will certainly revolutionize the practice of functional imaging since it can lower variability across institutions and may enhance the consistency of image interpretation independent of reader experience. In this paper, a novel automated system for the segmentation of oncological PET data aiming at providing an accurate quantitative analysis tool is proposed. The initial step involves expectation maximization (EM)-based mixture modeling using a k-means clustering procedure, which varies voxel order for initialization. A multiscale Markov model is then used to refine this segmentation by modeling spatial correlations between neighboring image voxels. An experimental study using an anthropomorphic thorax phantom was conducted for quantitative evaluation of the performance of the proposed segmentation algorithm. The comparison of actual tumor volumes to the volumes calculated using different segmentation methodologies including standard k-means, spatial domain Markov Random Field Model (MRFM), and the new multiscale MRFM proposed in this paper showed that the latter dramatically reduces the relative error to less than 8% for small lesions (7 mm radii) and less than 3.5% for larger lesions (9 mm radii). The analysis of the resulting segmentations of clinical oncologic PET data seems to confirm that this methodology shows promise and can successfully segment patient lesions. For problematic images, this technique enables the identification of tumors situated very close to nearby high normal physiologic uptake. The

  13. Segmentation of organs at risk in CT volumes of head, thorax, abdomen, and pelvis

    NASA Astrophysics Data System (ADS)

    Han, Miaofei; Ma, Jinfeng; Li, Yan; Li, Meiling; Song, Yanli; Li, Qiang

    2015-03-01

    Accurate segmentation of organs at risk (OARs) is a key step in treatment planning system (TPS) of image guided radiation therapy. We are developing three classes of methods to segment 17 organs at risk throughout the whole body, including brain, brain stem, eyes, mandible, temporomandibular joints, parotid glands, spinal cord, lungs, trachea, heart, livers, kidneys, spleen, prostate, rectum, femoral heads, and skin. The three classes of segmentation methods include (1) threshold-based methods for organs of large contrast with adjacent structures such as lungs, trachea, and skin; (2) context-driven Generalized Hough Transform-based methods combined with graph cut algorithm for robust localization and segmentation of liver, kidneys and spleen; and (3) atlas and registration-based methods for segmentation of heart and all organs in CT volumes of head and pelvis. The segmentation accuracy for the seventeen organs was subjectively evaluated by two medical experts in three levels of score: 0, poor (unusable in clinical practice); 1, acceptable (minor revision needed); and 2, good (nearly no revision needed). A database was collected from Ruijin Hospital, Huashan Hospital, and Xuhui Central Hospital in Shanghai, China, including 127 head scans, 203 thoracic scans, 154 abdominal scans, and 73 pelvic scans. The percentages of "good" segmentation results were 97.6%, 92.9%, 81.1%, 87.4%, 85.0%, 78.7%, 94.1%, 91.1%, 81.3%, 86.7%, 82.5%, 86.4%, 79.9%, 72.6%, 68.5%, 93.2%, 96.9% for brain, brain stem, eyes, mandible, temporomandibular joints, parotid glands, spinal cord, lungs, trachea, heart, livers, kidneys, spleen, prostate, rectum, femoral heads, and skin, respectively. Various organs at risk can be reliably segmented from CT scans by use of the three classes of segmentation methods.

  14. Generalized method for partial volume estimation and tissue segmentation in cerebral magnetic resonance images

    PubMed Central

    Khademi, April; Venetsanopoulos, Anastasios; Moody, Alan R.

    2014-01-01

    Abstract. An artifact found in magnetic resonance images (MRI) called partial volume averaging (PVA) has received much attention since accurate segmentation of cerebral anatomy and pathology is impeded by this artifact. Traditional neurological segmentation techniques rely on Gaussian mixture models to handle noise and PVA, or high-dimensional feature sets that exploit redundancy in multispectral datasets. Unfortunately, model-based techniques may not be optimal for images with non-Gaussian noise distributions and/or pathology, and multispectral techniques model probabilities instead of the partial volume (PV) fraction. For robust segmentation, a PV fraction estimation approach is developed for cerebral MRI that does not depend on predetermined intensity distribution models or multispectral scans. Instead, the PV fraction is estimated directly from each image using an adaptively defined global edge map constructed by exploiting a relationship between edge content and PVA. The final PVA map is used to segment anatomy and pathology with subvoxel accuracy. Validation on simulated and real, pathology-free T1 MRI (Gaussian noise), as well as pathological fluid attenuation inversion recovery MRI (non-Gaussian noise), demonstrate that the PV fraction is accurately estimated and the resultant segmentation is robust. Comparison to model-based methods further highlight the benefits of the current approach. PMID:26158022

  15. Partial volume segmentation in 3D of lesions and tissues in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Johnston, Brian; Atkins, M. Stella; Booth, Kellogg S.

    1994-05-01

    An important first step in diagnosis and treatment planning using tomographic imaging is differentiating and quantifying diseased as well as healthy tissue. One of the difficulties encountered in solving this problem to date has been distinguishing the partial volume constituents of each voxel in the image volume. Most proposed solutions to this problem involve analysis of planar images, in sequence, in two dimensions only. We have extended a model-based method of image segmentation which applies the technique of iterated conditional modes in three dimensions. A minimum of user intervention is required to train the algorithm. Partial volume estimates for each voxel in the image are obtained yielding fractional compositions of multiple tissue types for individual voxels. A multispectral approach is applied, where spatially registered data sets are available. The algorithm is simple and has been parallelized using a dataflow programming environment to reduce the computational burden. The algorithm has been used to segment dual echo MRI data sets of multiple sclerosis patients using lesions, gray matter, white matter, and cerebrospinal fluid as the partial volume constituents. The results of the application of the algorithm to these datasets is presented and compared to the manual lesion segmentation of the same data.

  16. Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET

    NASA Astrophysics Data System (ADS)

    Hatt, M.; Lamare, F.; Boussion, N.; Turzo, A.; Collet, C.; Salzenstein, F.; Roux, C.; Jarritt, P.; Carson, K.; Cheze-LeRest, C.; Visvikis, D.

    2007-07-01

    Accurate volume of interest (VOI) estimation in PET is crucial in different oncology applications such as response to therapy evaluation and radiotherapy treatment planning. The objective of our study was to evaluate the performance of the proposed algorithm for automatic lesion volume delineation; namely the fuzzy hidden Markov chains (FHMC), with that of current state of the art in clinical practice threshold based techniques. As the classical hidden Markov chain (HMC) algorithm, FHMC takes into account noise, voxel intensity and spatial correlation, in order to classify a voxel as background or functional VOI. However the novelty of the fuzzy model consists of the inclusion of an estimation of imprecision, which should subsequently lead to a better modelling of the 'fuzzy' nature of the object of interest boundaries in emission tomography data. The performance of the algorithms has been assessed on both simulated and acquired datasets of the IEC phantom, covering a large range of spherical lesion sizes (from 10 to 37 mm), contrast ratios (4:1 and 8:1) and image noise levels. Both lesion activity recovery and VOI determination tasks were assessed in reconstructed images using two different voxel sizes (8 mm3 and 64 mm3). In order to account for both the functional volume location and its size, the concept of % classification errors was introduced in the evaluation of volume segmentation using the simulated datasets. Results reveal that FHMC performs substantially better than the threshold based methodology for functional volume determination or activity concentration recovery considering a contrast ratio of 4:1 and lesion sizes of <28 mm. Furthermore differences between classification and volume estimation errors evaluated were smaller for the segmented volumes provided by the FHMC algorithm. Finally, the performance of the automatic algorithms was less susceptible to image noise levels in comparison to the threshold based techniques. The analysis of both

  17. Population Education Interchange. Volume 17, Numbers 1-4, 1988.

    ERIC Educational Resources Information Center

    Crews, Kimberly A.

    1988-01-01

    The four issues of this volume are each concerned with a specific topic in population studies. Issue number 1 , "Demographic Illiteracy," indicates that U.S. students are not aware of world population growth patterns. The information is taken from the Second International Science Study, 1983. An annotated list of 16 population studies resources is…

  18. Multi-stage learning for robust lung segmentation in challenging CT volumes.

    PubMed

    Sofka, Michal; Wetzl, Jens; Birkbeck, Neil; Zhang, Jingdan; Kohlberger, Timo; Kaftan, Jens; Declerck, Jérôme; Zhou, S Kevin

    2011-01-01

    Simple algorithms for segmenting healthy lung parenchyma in CT are unable to deal with high density tissue common in pulmonary diseases. To overcome this problem, we propose a multi-stage learning-based approach that combines anatomical information to predict an initialization of a statistical shape model of the lungs. The initialization first detects the carina of the trachea, and uses this to detect a set of automatically selected stable landmarks on regions near the lung (e.g., ribs, spine). These landmarks are used to align the shape model, which is then refined through boundary detection to obtain fine-grained segmentation. Robustness is obtained through hierarchical use of discriminative classifiers that are trained on a range of manually annotated data of diseased and healthy lungs. We demonstrate fast detection (35s per volume on average) and segmentation of 2 mm accuracy on challenging data.

  19. The position response of a large-volume segmented germanium detector

    NASA Astrophysics Data System (ADS)

    Descovich, M.; Nolan, P. J.; Boston, A. J.; Dobson, J.; Gros, S.; Cresswell, J. R.; Simpson, J.; Lazarus, I.; Regan, P. H.; Valiente-Dobon, J. J.; Sellin, P.; Pearson, C. J.

    2005-11-01

    The position response of a large-volume segmented coaxial germanium detector is reported. The detector has 24-fold segmentation on its outer contact. The output from each contact was sampled with fast digital signal processing electronics in order to determine the position of the γ-ray interaction from the signal pulse shape. The interaction position was reconstructed in a polar coordinate system by combining the radial information, contained in the rise-time of the pulse leading edge, with the azimuthal information, obtained from the magnitude of the transient charge signals induced on the neighbouring segments. With this method, a position resolution of 3-7 mm is achieved in both the radial and the azimuthal directions.

  20. 50 CFR 226.217 - Critical habitat for the Gulf of Maine Distinct Population Segment of Atlantic Salmon (Salmo salar).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Distinct Population Segment of Atlantic Salmon (Salmo salar). 226.217 Section 226.217 Wildlife and... Distinct Population Segment of Atlantic Salmon (Salmo salar). Critical habitat is designated to include all... the Gulf of Maine Distinct Population Segment of Atlantic Salmon (GOM DPS), except for...

  1. Population Bulletin, Volume 25 Number 5. A Sourcebook on Population.

    ERIC Educational Resources Information Center

    Moran, William E., Jr.

    This sourcebook includes an annotated bibliography of population literature, university centers, libraries, international organizations, and U. S. government programs in the field of population. The sourcebook is designed, first of all, to be useful for the concerned layman and secondly for the professional demographic community. The sourcebook is…

  2. 20 CFR 632.87 - Equitable provision of services to the eligible population and significant segments.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... eligible population and significant segments. 632.87 Section 632.87 Employees' Benefits EMPLOYMENT AND... Program Design and Management § 632.87 Equitable provision of services to the eligible population and... system is in place to afford all members of the eligible population within the service area for which...

  3. 20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... to subgroups on grounds prohibited by WIA section 188 and 29 CFR part 37, including tribal... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... population? (a) No, INA grantees cannot exclude segments of the eligible population. INA grantees...

  4. 20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... target services to subgroups on grounds prohibited by WIA section 188 and 29 CFR part 37, including... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... eligible population? (a) No, INA grantees cannot exclude segments of the eligible population. INA...

  5. 20 CFR 632.87 - Equitable provision of services to the eligible population and significant segments.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... eligible population and significant segments. 632.87 Section 632.87 Employees' Benefits EMPLOYMENT AND... Program Design and Management § 632.87 Equitable provision of services to the eligible population and... system is in place to afford all members of the eligible population within the service area for which...

  6. 20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... target services to subgroups on grounds prohibited by WIA section 188 and 29 CFR part 37, including... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... eligible population? (a) No, INA grantees cannot exclude segments of the eligible population. INA...

  7. 20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... target services to subgroups on grounds prohibited by WIA section 188 and 29 CFR part 37, including... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... eligible population? (a) No, INA grantees cannot exclude segments of the eligible population. INA...

  8. 20 CFR 632.87 - Equitable provision of services to the eligible population and significant segments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... eligible population and significant segments. 632.87 Section 632.87 Employees' Benefits EMPLOYMENT AND... Program Design and Management § 632.87 Equitable provision of services to the eligible population and... system is in place to afford all members of the eligible population within the service area for which...

  9. 20 CFR 668.650 - Can INA grantees exclude segments of the eligible population?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... to subgroups on grounds prohibited by WIA section 188 and 29 CFR part 37, including tribal... eligible population? 668.650 Section 668.650 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION... population? (a) No, INA grantees cannot exclude segments of the eligible population. INA grantees...

  10. Robust semi-automatic segmentation of single- and multichannel MRI volumes through adaptable class-specific representation

    NASA Astrophysics Data System (ADS)

    Nielsen, Casper F.; Passmore, Peter J.

    2002-05-01

    Segmentation of MRI volumes is complicated by noise, inhomogeneity and partial volume artefacts. Fully or semi-automatic methods often require time consuming or unintuitive initialization. Adaptable Class-Specific Representation (ACSR) is a semi-automatic segmentation framework implemented by the Path Growing Algorithm (PGA), which reduces artefacts near segment boundaries. The user visually defines the desired segment classes through the selection of class templates and the following segmentation process is fully automatic. Good results have previously been achieved with color cryo section segmentation and ACSR has been developed further for the MRI modality. In this paper we present two optimizations for robust ACSR segmentation of MRI volumes. Automatic template creation based on an initial segmentation step using Learning Vector Quantization is applied for higher robustness to noise. Inhomogeneity correction is added as a pre-processing step, comparing the EQ and N3 algorithms. Results based on simulated T1-weighed and multispectral (T1 and T2) MRI data from the BrainWeb database and real data from the Internet Brain Segmentation Repository are presented. We show that ACSR segmentation compares favorably to previously published results on the same volumes and discuss the pros and cons of using quantitative ground truth evaluation compared to qualitative visual assessment.

  11. Volume analysis of treatment response of head and neck lesions using 3D level set segmentation

    NASA Astrophysics Data System (ADS)

    Hadjiiski, Lubomir; Street, Ethan; Sahiner, Berkman; Gujar, Sachin; Ibrahim, Mohannad; Chan, Heang-Ping; Mukherji, Suresh K.

    2008-03-01

    A computerized system for segmenting lesions in head and neck CT scans was developed to assist radiologists in estimation of the response to treatment of malignant lesions. The system performs 3D segmentations based on a level set model and uses as input an approximate bounding box for the lesion of interest. In this preliminary study, CT scans from a pre-treatment exam and a post one-cycle chemotherapy exam of 13 patients containing head and neck neoplasms were used. A radiologist marked 35 temporal pairs of lesions. 13 pairs were primary site cancers and 22 pairs were metastatic lymph nodes. For all lesions, a radiologist outlined a contour on the best slice on both the pre- and post treatment scans. For the 13 primary lesion pairs, full 3D contours were also extracted by a radiologist. The average pre- and post-treatment areas on the best slices for all lesions were 4.5 and 2.1 cm2, respectively. For the 13 primary site pairs the average pre- and post-treatment primary lesions volumes were 15.4 and 6.7 cm 3 respectively. The correlation between the automatic and manual estimates for the pre-to-post-treatment change in area for all 35 pairs was r=0.97, while the correlation for the percent change in area was r=0.80. The correlation for the change in volume for the 13 primary site pairs was r=0.89, while the correlation for the percent change in volume was r=0.79. The average signed percent error between the automatic and manual areas for all 70 lesions was 11.0+/-20.6%. The average signed percent error between the automatic and manual volumes for all 26 primary lesions was 37.8+/-42.1%. The preliminary results indicate that the automated segmentation system can reliably estimate tumor size change in response to treatment relative to radiologist's hand segmentation.

  12. Semiautomatic regional segmentation to measure orbital fat volumes in thyroid-associated ophthalmopathy. A validation study.

    PubMed

    Comerci, M; Elefante, A; Strianese, D; Senese, R; Bonavolontà, P; Alfano, B; Bonavolontà, B; Brunetti, A

    2013-08-01

    This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data.

  13. Automatic segmentation of blood vessels from MR angiography volume data by using fuzzy logic technique

    NASA Astrophysics Data System (ADS)

    Kobashi, Syoji; Hata, Yutaka; Tokimoto, Yasuhiro; Ishikawa, Makato

    1999-05-01

    This paper shows a novel medical image segmentation method applied to blood vessel segmentation from magnetic resonance angiography volume data. The principle idea of the method is fuzzy information granulation concept. The method consists of 2 parts: (1) quantization and feature extraction, (2) iterative fuzzy synthesis. In the first part, volume quantization is performed with watershed segmentation technique. Each quantum is represented by three features, vascularity, narrowness and histogram consistency. Using these features, we estimate the fuzzy degrees of each quantum for knowledge models about MRA volume data. In the second part, the method increases the fuzzy degrees by selectively synthesizing neighboring quantums. As a result, we obtain some synthesized quantums. We regard them as fuzzy granules and classify them into blood vessel or fat by evaluating the fuzzy degrees. In the experimental result, three dimensional images are generated using target maximum intensity projection (MIP) and surface shaded display. The comparison with conventional MIP images shows that the unclarity region in conventional images are clearly depict in our images. The qualitative evaluation done by a physician shows that our method can extract blood vessel region and that the results are useful to diagnose the cerebral diseases.

  14. Hitchhiker’s Guide to Voxel Segmentation for Partial Volume Correction of In Vivo Magnetic Resonance Spectroscopy

    PubMed Central

    Quadrelli, Scott; Mountford, Carolyn; Ramadan, Saadallah

    2016-01-01

    Partial volume effects have the potential to cause inaccuracies when quantifying metabolites using proton magnetic resonance spectroscopy (MRS). In order to correct for cerebrospinal fluid content, a spectroscopic voxel needs to be segmented according to different tissue contents. This article aims to detail how automated partial volume segmentation can be undertaken and provides a software framework for researchers to develop their own tools. While many studies have detailed the impact of partial volume correction on proton magnetic resonance spectroscopy quantification, there is a paucity of literature explaining how voxel segmentation can be achieved using freely available neuroimaging packages. PMID:27147822

  15. Automated cerebellar segmentation: Validation and application to detect smaller volumes in children prenatally exposed to alcohol☆

    PubMed Central

    Cardenas, Valerie A.; Price, Mathew; Infante, M. Alejandra; Moore, Eileen M.; Mattson, Sarah N.; Riley, Edward P.; Fein, George

    2014-01-01

    Objective To validate an automated cerebellar segmentation method based on active shape and appearance modeling and then segment the cerebellum on images acquired from adolescents with histories of prenatal alcohol exposure (PAE) and non-exposed controls (NC). Methods Automated segmentations of the total cerebellum, right and left cerebellar hemispheres, and three vermal lobes (anterior, lobules I–V; superior posterior, lobules VI–VII; inferior posterior, lobules VIII–X) were compared to expert manual labelings on 20 subjects, studied twice, that were not used for model training. The method was also used to segment the cerebellum on 11 PAE and 9 NC adolescents. Results The test–retest intraclass correlation coefficients (ICCs) of the automated method were greater than 0.94 for all cerebellar volume and mid-sagittal vermal area measures, comparable or better than the test–retest ICCs for manual measurement (all ICCs > 0.92). The ICCs computed on all four cerebellar measurements (manual and automated measures on the repeat scans) to compare comparability were above 0.97 for non-vermis parcels, and above 0.89 for vermis parcels. When applied to patients, the automated method detected smaller cerebellar volumes and mid-sagittal areas in the PAE group compared to controls (p < 0.05 for all regions except the superior posterior lobe, consistent with prior studies). Discussion These results demonstrate excellent reliability and validity of automated cerebellar volume and mid-sagittal area measurements, compared to manual measurements. These data also illustrate that this new technology for automatically delineating the cerebellum leads to conclusions regarding the effects of prenatal alcohol exposure on the cerebellum consistent with prior studies that used labor intensive manual delineation, even with a very small sample. PMID:25061566

  16. A unifying framework for partial volume segmentation of brain MR images.

    PubMed

    Van Leemput, Koen; Maes, Frederik; Vandermeulen, Dirk; Suetens, Paul

    2003-01-01

    Accurate brain tissue segmentation by intensity-based voxel classification of magnetic resonance (MR) images is complicated by partial volume (PV) voxels that contain a mixture of two or more tissue types. In this paper, we present a statistical framework for PV segmentation that encompasses and extends existing techniques. We start from a commonly used parametric statistical image model in which each voxel belongs to one single tissue type, and introduce an additional downsampling step that causes partial voluming along the borders between tissues. An expectation-maximization approach is used to simultaneously estimate the parameters of the resulting model and perform a PV classification. We present results on well-chosen simulated images and on real MR images of the brain, and demonstrate that the use of appropriate spatial prior knowledge not only improves the classifications, but is often indispensable for robust parameter estimation as well. We conclude that general robust PV segmentation of MR brain images requires statistical models that describe the spatial distribution of brain tissues more accurately than currently available models.

  17. A novel colonic polyp volume segmentation method for computer tomographic colonography

    NASA Astrophysics Data System (ADS)

    Wang, Huafeng; Li, Lihong C.; Han, Hao; Song, Bowen; Peng, Hao; Wang, Yunhong; Wang, Lihua; Liang, Zhengrong

    2014-03-01

    Colorectal cancer is the third most common type of cancer. However, this disease can be prevented by detection and removal of precursor adenomatous polyps after the diagnosis given by experts on computer tomographic colonography (CTC). During CTC diagnosis, the radiologist looks for colon polyps and measures not only the size but also the malignancy. It is a common sense that to segment polyp volumes from their complicated growing environment is of much significance for accomplishing the CTC based early diagnosis task. Previously, the polyp volumes are mainly given from the manually or semi-automatically drawing by the radiologists. As a result, some deviations cannot be avoided since the polyps are usually small (6~9mm) and the radiologists' experience and knowledge are varying from one to another. In order to achieve automatic polyp segmentation carried out by the machine, we proposed a new method based on the colon decomposition strategy. We evaluated our algorithm on both phantom and patient data. Experimental results demonstrate our approach is capable of segment the small polyps from their complicated growing background.

  18. Hierarchical probabilistic Gabor and MRF segmentation of brain tumours in MRI volumes.

    PubMed

    Subbanna, Nagesh K; Precup, Doina; Collins, D Louis; Arbel, Tal

    2013-01-01

    In this paper, we present a fully automated hierarchical probabilistic framework for segmenting brain tumours from multispectral human brain magnetic resonance images (MRIs) using multiwindow Gabor filters and an adapted Markov Random Field (MRF) framework. In the first stage, a customised Gabor decomposition is developed, based on the combined-space characteristics of the two classes (tumour and non-tumour) in multispectral brain MRIs in order to optimally separate tumour (including edema) from healthy brain tissues. A Bayesian framework then provides a coarse probabilistic texture-based segmentation of tumours (including edema) whose boundaries are then refined at the voxel level through a modified MRF framework that carefully separates the edema from the main tumour. This customised MRF is not only built on the voxel intensities and class labels as in traditional MRFs, but also models the intensity differences between neighbouring voxels in the likelihood model, along with employing a prior based on local tissue class transition probabilities. The second inference stage is shown to resolve local inhomogeneities and impose a smoothing constraint, while also maintaining the appropriate boundaries as supported by the local intensity difference observations. The method was trained and tested on the publicly available MICCAI 2012 Brain Tumour Segmentation Challenge (BRATS) Database [1] on both synthetic and clinical volumes (low grade and high grade tumours). Our method performs well compared to state-of-the-art techniques, outperforming the results of the top methods in cases of clinical high grade and low grade tumour core segmentation by 40% and 45% respectively.

  19. A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging

    NASA Astrophysics Data System (ADS)

    Martin, Spencer; Brophy, Mark; Palma, David; Louie, Alexander V.; Yu, Edward; Yaremko, Brian; Ahmad, Belal; Barron, John L.; Beauchemin, Steven S.; Rodrigues, George; Gaede, Stewart

    2015-02-01

    This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development.

  20. Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET

    PubMed Central

    Hatt, Mathieu; Lamare, Frédéric; Boussion, Nicolas; Roux, Christian; Turzo, Alexandre; Cheze-Lerest, Catherine; Jarritt, Peter; Carson, Kathryn; Salzenstein, Fabien; Collet, Christophe; Visvikis, Dimitris

    2007-01-01

    Accurate volume of interest (VOI) estimation in PET is crucial in different oncology applications such as response to therapy evaluation and radiotherapy treatment planning. The objective of our study was to evaluate the performance of the proposed algorithm for automatic lesion volume delineation; namely the Fuzzy Hidden Markov Chains (FHMC), with that of current state of the art in clinical practice threshold based techniques. As the classical Hidden Markov Chain (HMC) algorithm, FHMC takes into account noise, voxel’s intensity and spatial correlation, in order to classify a voxel as background or functional VOI. However the novelty of the fuzzy model consists of the inclusion of an estimation of imprecision, which should subsequently lead to a better modelling of the “fuzzy” nature of the object on interest boundaries in emission tomography data. The performance of the algorithms has been assessed on both simulated and acquired datasets of the IEC phantom, covering a large range of spherical lesion sizes (from 10 to 37mm), contrast ratios (4:1 and 8:1) and image noise levels. Both lesion activity recovery and VOI determination tasks were assessed in reconstructed images using two different voxel sizes (8mm3 and 64mm3). In order to account for both the functional volume location and its size, the concept of % classification errors was introduced in the evaluation of volume segmentation using the simulated datasets. Results reveal that FHMC performs substantially better than the threshold based methodology for functional volume determination or activity concentration recovery considering a contrast ratio of 4:1 and lesion sizes of <28mm. Furthermore differences between classification and volume estimation errors evaluated were smaller for the segmented volumes provided by the FHMC algorithm. Finally, the performance of the automatic algorithms was less susceptible to image noise levels in comparison to the threshold based techniques. The analysis of both

  1. Markov random field model for segmenting large populations of lipid vesicles from micrographs.

    PubMed

    Zupanc, Jernej; Drobne, Damjana; Ster, Branko

    2011-12-01

    Giant unilamellar lipid vesicles, artificial replacements for cell membranes, are a promising tool for in vitro assessment of interactions between products of nanotechnologies and biological membranes. However, the effect of nanoparticles can not be derived from observations on a single specimen, vesicle populations should be observed instead. We propose an adaptation of the Markov random field image segmentation model which allows detection and segmentation of numerous vesicles in micrographs. The reliability of this model with different lighting, blur, and noise characteristics of micrographs is examined and discussed. Moreover, the automatic segmentation is tested on micrographs with thousands of vesicles and the result is compared to that of manual segmentation. The segmentation step presented is part of a methodology we are developing for bio-nano interaction assessment studies on lipid vesicles.

  2. A modified probabilistic neural network for partial volume segmentation in brain MR image.

    PubMed

    Song, Tao; Jamshidi, Mo M; Lee, Roland R; Huang, Mingxiong

    2007-09-01

    A modified probabilistic neural network (PNN) for brain tissue segmentation with magnetic resonance imaging (MRI) is proposed. In this approach, covariance matrices are used to replace the singular smoothing factor in the PNN's kernel function, and weighting factors are added in the pattern of summation layer. This weighted probabilistic neural network (WPNN) classifier can account for partial volume effects, which exist commonly in MRI, not only in the final result stage, but also in the modeling process. It adopts the self-organizing map (SOM) neural network to overly segment the input MR image, and yield reference vectors necessary for probabilistic density function (pdf) estimation. A supervised "soft" labeling mechanism based on Bayesian rule is developed, so that weighting factors can be generated along with corresponding SOM reference vectors. Tissue classification results from various algorithms are compared, and the effectiveness and robustness of the proposed approach are demonstrated. PMID:18220190

  3. Dedicated breast CT: Fibroglandular volume measurements in a diagnostic population

    SciTech Connect

    Vedantham, Srinivasan; Shi Linxi; Karellas, Andrew; O'Connell, Avice M.

    2012-12-15

    Purpose: To determine the mean and range of volumetric glandular fraction (VGF) of the breast in a diagnostic population using a high-resolution flat-panel cone-beam dedicated breast CT system. This information is important for Monte Carlo-based estimation of normalized glandular dose coefficients and for investigating the dependence of VGF on breast dimensions, race, and pathology. Methods: Image data from a clinical trial investigating the role of dedicated breast CT that enrolled 150 women were retrospectively analyzed to determine the VGF. The study was conducted in adherence to a protocol approved by the institutional human subjects review boards and written informed consent was obtained from all study participants. All participants in the study were assigned BI-RADS{sup Registered-Sign} 4 or 5 as per the American College of Radiology assessment categories after standard diagnostic work-up and underwent dedicated breast CT exam prior to biopsy. A Gaussian-kernel based fuzzy c-means algorithm was used to partition the breast CT images into adipose and fibroglandular tissue after segmenting the skin. Upon determination of the accuracy of the algorithm with a phantom, it was applied to 137 breast CT volumes from 136 women. VGF was determined for each breast and the mean and range were determined. Pathology results with classification as benign, malignant, and hyperplasia were available for 132 women, and were used to investigate if the distributions of VGF varied with pathology. Results: The algorithm was accurate to within {+-}1.9% in determining the volume of an irregular shaped phantom. The study mean ({+-} inter-breast SD) for the VGF was 0.172 {+-} 0.142 (range: 0.012-0.719). VGF was found to be negatively correlated with age, breast dimensions (chest-wall to nipple length, pectoralis to nipple length, and effective diameter at chest-wall), and total breast volume, and positively correlated with fibroglandular volume. Based on pathology, pairwise statistical

  4. Segmentation of cerebral MRI scans using a partial volume model, shading correction, and an anatomical prior

    NASA Astrophysics Data System (ADS)

    Noe, Aljaz; Kovacic, Stanislav; Gee, James C.

    2001-07-01

    A mixture-model clustering algorithm is presented for robust MRI brain image segmentation in the presence of partial volume averaging. The method uses additional classes to represent partial volume voxels of mixed tissue type in the image. Probability distributions for partial volume voxels are modeled accordingly. The image model also allows for tissue-dependent variance values and voxel neighborhood information is taken into account in the clustering formulation. Additionally we extend the image model to account for a low frequency intensity inhomogeneity that may be present in an image. This so-called shading effect is modeled as a linear combination of polynomial basis functions, and is estimated within the clustering algorithm. We also investigate the possibility of using additional anatomical prior information obtained by registering tissue class template images to the image to be segmented. The final result is the estimated fractional amount of each tissue type present within a voxel in addition to the label assigned to the voxel. A parallel implementation of the method is evaluated using synthetic and real MRI data.

  5. Semiautomatic bladder segmentation on CBCT using a population-based model for multiple-plan ART of bladder cancer

    NASA Astrophysics Data System (ADS)

    Chai, Xiangfei; van Herk, Marcel; Betgen, Anja; Hulshof, Maarten; Bel, Arjan

    2012-12-01

    The aim of this study is to develop a novel semiautomatic bladder segmentation approach for selecting the appropriate plan from the library of plans for a multiple-plan adaptive radiotherapy (ART) procedure. A population-based statistical bladder model was first built from a training data set (95 bladder contours from 8 patients). This model was then used as constraint to segment the bladder in an independent validation data set (233 CBCT scans from the remaining 22 patients). All 3D bladder contours were converted into parametric surface representations using spherical harmonic expansion. Principal component analysis (PCA) was applied in the spherical harmonic-based shape parameter space to calculate the major variation of bladder shapes. The number of dominating PCA modes was chosen such that 95% of the total shape variation of the training data set was described. The automatic segmentation started from the bladder contour of the planning CT of each patient, which was modified by changing the weight of each PCA mode. As a result, the segmentation contour was deformed consistently with the training set to best fit the bladder boundary in the localization CBCT image. A cost function was defined to measure the goodness of fit of the segmentation on the localization CBCT image. The segmentation was obtained by minimizing this cost function using a simplex optimizer. After automatic segmentation, a fast manual correction method was provided to correct those bladders (parts) that were poorly segmented. Volume- and distance-based metrics and the accuracy of plan selection from multiple plans were evaluated to quantify the performance of the automatic and semiautomatic segmentation methods. For the training data set, only seven PCA modes were needed to represent 95% of the bladder shape variation. The mean CI overlap and residual error (SD) of automatic bladder segmentation over all of the validation data were 70.5% and 0.39 cm, respectively. The agreement of plan

  6. Semi-automatic segmentation of brain tumors using population and individual information.

    PubMed

    Wu, Yao; Yang, Wei; Jiang, Jun; Li, Shuanqian; Feng, Qianjin; Chen, Wufan

    2013-08-01

    Efficient segmentation of tumors in medical images is of great practical importance in early diagnosis and radiation plan. This paper proposes a novel semi-automatic segmentation method based on population and individual statistical information to segment brain tumors in magnetic resonance (MR) images. First, high-dimensional image features are extracted. Neighborhood components analysis is proposed to learn two optimal distance metrics, which contain population and patient-specific information, respectively. The probability of each pixel belonging to the foreground (tumor) and the background is estimated by the k-nearest neighborhood classifier under the learned optimal distance metrics. A cost function for segmentation is constructed through these probabilities and is optimized using graph cuts. Finally, some morphological operations are performed to improve the achieved segmentation results. Our dataset consists of 137 brain MR images, including 68 for training and 69 for testing. The proposed method overcomes segmentation difficulties caused by the uneven gray level distribution of the tumors and even can get satisfactory results if the tumors have fuzzy edges. Experimental results demonstrate that the proposed method is robust to brain tumor segmentation. PMID:23319111

  7. Real-Time Automatic Segmentation of Optical Coherence Tomography Volume Data of the Macular Region

    PubMed Central

    Tian, Jing; Varga, Boglárka; Somfai, Gábor Márk; Lee, Wen-Hsiang; Smiddy, William E.; Cabrera DeBuc, Delia

    2015-01-01

    Optical coherence tomography (OCT) is a high speed, high resolution and non-invasive imaging modality that enables the capturing of the 3D structure of the retina. The fast and automatic analysis of 3D volume OCT data is crucial taking into account the increased amount of patient-specific 3D imaging data. In this work, we have developed an automatic algorithm, OCTRIMA 3D (OCT Retinal IMage Analysis 3D), that could segment OCT volume data in the macular region fast and accurately. The proposed method is implemented using the shortest-path based graph search, which detects the retinal boundaries by searching the shortest-path between two end nodes using Dijkstra’s algorithm. Additional techniques, such as inter-frame flattening, inter-frame search region refinement, masking and biasing were introduced to exploit the spatial dependency between adjacent frames for the reduction of the processing time. Our segmentation algorithm was evaluated by comparing with the manual labelings and three state of the art graph-based segmentation methods. The processing time for the whole OCT volume of 496×644×51 voxels (captured by Spectralis SD-OCT) was 26.15 seconds which is at least a 2-8-fold increase in speed compared to other, similar reference algorithms used in the comparisons. The average unsigned error was about 1 pixel (∼ 4 microns), which was also lower compared to the reference algorithms. We believe that OCTRIMA 3D is a leap forward towards achieving reliable, real-time analysis of 3D OCT retinal data. PMID:26258430

  8. Early Expansion of the Intracranial CSF Volume After Palliative Whole-Brain Radiotherapy: Results of a Longitudinal CT Segmentation Analysis

    SciTech Connect

    Sanghera, Paul; Gardner, Sandra L.; Scora, Daryl; Davey, Phillip

    2010-03-15

    Purpose: To assess cerebral atrophy after radiotherapy, we measured intracranial cerebrospinal fluid volume (ICSFV) over time after whole-brain radiotherapy (WBRT) and compared it with published normal-population data. Methods and Materials: We identified 9 patients receiving a single course of WBRT (30 Gy in 10 fractions over 2 weeks) for ipsilateral brain metastases with at least 3 years of computed tomography follow-up. Segmentation analysis was confined to the tumor-free hemi-cranium. The technique was semiautomated by use of thresholds based on scanned image intensity. The ICSFV percentage (ratio of ICSFV to brain volume) was used for modeling purposes. Published normal-population ICSFV percentages as a function of age were used as a control. A repeated-measures model with cross-sectional (between individuals) and longitudinal (within individuals) quadratic components was fitted to the collected data. The influence of clinical factors including the use of subependymal plate shielding was studied. Results: The median imaging follow-up was 6.25 years. There was an immediate increase (p < 0.0001) in ICSFV percentage, which decelerated over time. The clinical factors studied had no significant effect on the model. Conclusions: WBRT immediately accelerates the rate of brain atrophy. This longitudinal study in patients with brain metastases provides a baseline against which the potential benefits of more localized radiotherapeutic techniques such as radiosurgery may be compared.

  9. Associations between Family Adversity and Brain Volume in Adolescence: Manual vs. Automated Brain Segmentation Yields Different Results

    PubMed Central

    Lyden, Hannah; Gimbel, Sarah I.; Del Piero, Larissa; Tsai, A. Bryna; Sachs, Matthew E.; Kaplan, Jonas T.; Margolin, Gayla; Saxbe, Darby

    2016-01-01

    Associations between brain structure and early adversity have been inconsistent in the literature. These inconsistencies may be partially due to methodological differences. Different methods of brain segmentation may produce different results, obscuring the relationship between early adversity and brain volume. Moreover, adolescence is a time of significant brain growth and certain brain areas have distinct rates of development, which may compromise the accuracy of automated segmentation approaches. In the current study, 23 adolescents participated in two waves of a longitudinal study. Family aggression was measured when the youths were 12 years old, and structural scans were acquired an average of 4 years later. Bilateral amygdalae and hippocampi were segmented using three different methods (manual tracing, FSL, and NeuroQuant). The segmentation estimates were compared, and linear regressions were run to assess the relationship between early family aggression exposure and all three volume segmentation estimates. Manual tracing results showed a positive relationship between family aggression and right amygdala volume, whereas FSL segmentation showed negative relationships between family aggression and both the left and right hippocampi. However, results indicate poor overlap between methods, and different associations were found between early family aggression exposure and brain volume depending on the segmentation method used. PMID:27656121

  10. Associations between Family Adversity and Brain Volume in Adolescence: Manual vs. Automated Brain Segmentation Yields Different Results.

    PubMed

    Lyden, Hannah; Gimbel, Sarah I; Del Piero, Larissa; Tsai, A Bryna; Sachs, Matthew E; Kaplan, Jonas T; Margolin, Gayla; Saxbe, Darby

    2016-01-01

    Associations between brain structure and early adversity have been inconsistent in the literature. These inconsistencies may be partially due to methodological differences. Different methods of brain segmentation may produce different results, obscuring the relationship between early adversity and brain volume. Moreover, adolescence is a time of significant brain growth and certain brain areas have distinct rates of development, which may compromise the accuracy of automated segmentation approaches. In the current study, 23 adolescents participated in two waves of a longitudinal study. Family aggression was measured when the youths were 12 years old, and structural scans were acquired an average of 4 years later. Bilateral amygdalae and hippocampi were segmented using three different methods (manual tracing, FSL, and NeuroQuant). The segmentation estimates were compared, and linear regressions were run to assess the relationship between early family aggression exposure and all three volume segmentation estimates. Manual tracing results showed a positive relationship between family aggression and right amygdala volume, whereas FSL segmentation showed negative relationships between family aggression and both the left and right hippocampi. However, results indicate poor overlap between methods, and different associations were found between early family aggression exposure and brain volume depending on the segmentation method used.

  11. Associations between Family Adversity and Brain Volume in Adolescence: Manual vs. Automated Brain Segmentation Yields Different Results

    PubMed Central

    Lyden, Hannah; Gimbel, Sarah I.; Del Piero, Larissa; Tsai, A. Bryna; Sachs, Matthew E.; Kaplan, Jonas T.; Margolin, Gayla; Saxbe, Darby

    2016-01-01

    Associations between brain structure and early adversity have been inconsistent in the literature. These inconsistencies may be partially due to methodological differences. Different methods of brain segmentation may produce different results, obscuring the relationship between early adversity and brain volume. Moreover, adolescence is a time of significant brain growth and certain brain areas have distinct rates of development, which may compromise the accuracy of automated segmentation approaches. In the current study, 23 adolescents participated in two waves of a longitudinal study. Family aggression was measured when the youths were 12 years old, and structural scans were acquired an average of 4 years later. Bilateral amygdalae and hippocampi were segmented using three different methods (manual tracing, FSL, and NeuroQuant). The segmentation estimates were compared, and linear regressions were run to assess the relationship between early family aggression exposure and all three volume segmentation estimates. Manual tracing results showed a positive relationship between family aggression and right amygdala volume, whereas FSL segmentation showed negative relationships between family aggression and both the left and right hippocampi. However, results indicate poor overlap between methods, and different associations were found between early family aggression exposure and brain volume depending on the segmentation method used.

  12. Associations between Family Adversity and Brain Volume in Adolescence: Manual vs. Automated Brain Segmentation Yields Different Results.

    PubMed

    Lyden, Hannah; Gimbel, Sarah I; Del Piero, Larissa; Tsai, A Bryna; Sachs, Matthew E; Kaplan, Jonas T; Margolin, Gayla; Saxbe, Darby

    2016-01-01

    Associations between brain structure and early adversity have been inconsistent in the literature. These inconsistencies may be partially due to methodological differences. Different methods of brain segmentation may produce different results, obscuring the relationship between early adversity and brain volume. Moreover, adolescence is a time of significant brain growth and certain brain areas have distinct rates of development, which may compromise the accuracy of automated segmentation approaches. In the current study, 23 adolescents participated in two waves of a longitudinal study. Family aggression was measured when the youths were 12 years old, and structural scans were acquired an average of 4 years later. Bilateral amygdalae and hippocampi were segmented using three different methods (manual tracing, FSL, and NeuroQuant). The segmentation estimates were compared, and linear regressions were run to assess the relationship between early family aggression exposure and all three volume segmentation estimates. Manual tracing results showed a positive relationship between family aggression and right amygdala volume, whereas FSL segmentation showed negative relationships between family aggression and both the left and right hippocampi. However, results indicate poor overlap between methods, and different associations were found between early family aggression exposure and brain volume depending on the segmentation method used. PMID:27656121

  13. Chest-wall segmentation in automated 3D breast ultrasound images using thoracic volume classification

    NASA Astrophysics Data System (ADS)

    Tan, Tao; van Zelst, Jan; Zhang, Wei; Mann, Ritse M.; Platel, Bram; Karssemeijer, Nico

    2014-03-01

    Computer-aided detection (CAD) systems are expected to improve effectiveness and efficiency of radiologists in reading automated 3D breast ultrasound (ABUS) images. One challenging task on developing CAD is to reduce a large number of false positives. A large amount of false positives originate from acoustic shadowing caused by ribs. Therefore determining the location of the chestwall in ABUS is necessary in CAD systems to remove these false positives. Additionally it can be used as an anatomical landmark for inter- and intra-modal image registration. In this work, we extended our previous developed chestwall segmentation method that fits a cylinder to automated detected rib-surface points and we fit the cylinder model by minimizing a cost function which adopted a term of region cost computed from a thoracic volume classifier to improve segmentation accuracy. We examined the performance on a dataset of 52 images where our previous developed method fails. Using region-based cost, the average mean distance of the annotated points to the segmented chest wall decreased from 7.57±2.76 mm to 6.22±2.86 mm.art.

  14. Automatic delineation of tumor volumes by co-segmentation of combined PET/MR data

    NASA Astrophysics Data System (ADS)

    Leibfarth, S.; Eckert, F.; Welz, S.; Siegel, C.; Schmidt, H.; Schwenzer, N.; Zips, D.; Thorwarth, D.

    2015-07-01

    Combined PET/MRI may be highly beneficial for radiotherapy treatment planning in terms of tumor delineation and characterization. To standardize tumor volume delineation, an automatic algorithm for the co-segmentation of head and neck (HN) tumors based on PET/MR data was developed. Ten HN patient datasets acquired in a combined PET/MR system were available for this study. The proposed algorithm uses both the anatomical T2-weighted MR and FDG-PET data. For both imaging modalities tumor probability maps were derived, assigning each voxel a probability of being cancerous based on its signal intensity. A combination of these maps was subsequently segmented using a threshold level set algorithm. To validate the method, tumor delineations from three radiation oncologists were available. Inter-observer variabilities and variabilities between the algorithm and each observer were quantified by means of the Dice similarity index and a distance measure. Inter-observer variabilities and variabilities between observers and algorithm were found to be comparable, suggesting that the proposed algorithm is adequate for PET/MR co-segmentation. Moreover, taking into account combined PET/MR data resulted in more consistent tumor delineations compared to MR information only.

  15. Segmentation of interest region in medical volume images using geometric deformable model.

    PubMed

    Lee, Myungeun; Cho, Wanhyun; Kim, Sunworl; Park, Soonyoung; Kim, Jong Hyo

    2012-05-01

    In this paper, we present a new segmentation method using the level set framework for medical volume images. The method was implemented using the surface evolution principle based on the geometric deformable model and the level set theory. And, the speed function in the level set approach consists of a hybrid combination of three integral measures derived from the calculus of variation principle. The terms are defined as robust alignment, active region, and smoothing. These terms can help to obtain the precise surface of the target object and prevent the boundary leakage problem. The proposed method has been tested on synthetic and various medical volume images with normal tissue and tumor regions in order to evaluate its performance on visual and quantitative data. The quantitative validation of the proposed segmentation is shown with higher Jaccard's measure score (72.52%-94.17%) and lower Hausdorff distance (1.2654 mm-3.1527 mm) than the other methods such as mean speed (67.67%-93.36% and 1.3361mm-3.4463 mm), mean-variance speed (63.44%-94.72% and 1.3361 mm-3.4616 mm), and edge-based speed (0.76%-42.44% and 3.8010 mm-6.5389 mm). The experimental results confirm that the effectiveness and performance of our method is excellent compared with traditional approaches. PMID:22402196

  16. 3D robust Chan-Vese model for industrial computed tomography volume data segmentation

    NASA Astrophysics Data System (ADS)

    Liu, Linghui; Zeng, Li; Luan, Xiao

    2013-11-01

    Industrial computed tomography (CT) has been widely applied in many areas of non-destructive testing (NDT) and non-destructive evaluation (NDE). In practice, CT volume data to be dealt with may be corrupted by noise. This paper addresses the segmentation of noisy industrial CT volume data. Motivated by the research on the Chan-Vese (CV) model, we present a region-based active contour model that draws upon intensity information in local regions with a controllable scale. In the presence of noise, a local energy is firstly defined according to the intensity difference within a local neighborhood. Then a global energy is defined to integrate local energy with respect to all image points. In a level set formulation, this energy is represented by a variational level set function, where a surface evolution equation is derived for energy minimization. Comparative analysis with the CV model indicates the comparable performance of the 3D robust Chan-Vese (RCV) model. The quantitative evaluation also shows the segmentation accuracy of 3D RCV. In addition, the efficiency of our approach is validated under several types of noise, such as Poisson noise, Gaussian noise, salt-and-pepper noise and speckle noise.

  17. Multi-atlas segmentation of the cartilage in knee MR images with sequential volume- and bone-mask-based registrations

    NASA Astrophysics Data System (ADS)

    Lee, Han Sang; Kim, Hyeun A.; Kim, Hyeonjin; Hong, Helen; Yoon, Young Cheol; Kim, Junmo

    2016-03-01

    In spite of its clinical importance in diagnosis of osteoarthritis, segmentation of cartilage in knee MRI remains a challenging task due to its shape variability and low contrast with surrounding soft tissues and synovial fluid. In this paper, we propose a multi-atlas segmentation of cartilage in knee MRI with sequential atlas registrations and locallyweighted voting (LWV). First, bone is segmented by sequential volume- and object-based registrations and LWV. Second, to overcome the shape variability of cartilage, cartilage is segmented by bone-mask-based registration and LWV. In experiments, the proposed method improved the bone segmentation by reducing misclassified bone region, and enhanced the cartilage segmentation by preventing cartilage leakage into surrounding similar intensity region, with the help of sequential registrations and LWV.

  18. Brain tumor target volume determination for radiation therapy treatment planning through the use of automated MRI segmentation

    NASA Astrophysics Data System (ADS)

    Mazzara, Gloria Patrika

    Radiation therapy seeks to effectively irradiate the tumor cells while minimizing the dose to adjacent normal cells. Prior research found that the low success rates for treating brain tumors would be improved with higher radiation doses to the tumor area. This is feasible only if the target volume can be precisely identified. However, the definition of tumor volume is still based on time-intensive, highly subjective manual outlining by radiation oncologists. In this study the effectiveness of two automated Magnetic Resonance Imaging (MRI) segmentation methods, k-Nearest Neighbors (kNN) and Knowledge-Guided (KG), in determining the Gross Tumor Volume (GTV) of brain tumors for use in radiation therapy was assessed. Three criteria were applied: accuracy of the contours; quality of the resulting treatment plan in terms of dose to the tumor; and a novel treatment plan evaluation technique based on post-treatment images. The kNN method was able to segment all cases while the KG method was limited to enhancing tumors and gliomas with clear enhancing edges. Various software applications were developed to create a closed smooth contour that encompassed the tumor pixels from the segmentations and to integrate these results into the treatment planning software. A novel, probabilistic measurement of accuracy was introduced to compare the agreement of the segmentation methods with the weighted average physician volume. Both computer methods under-segment the tumor volume when compared with the physicians but performed within the variability of manual contouring (28% +/- 12% for inter-operator variability). Computer segmentations were modified vertically to compensate for their under-segmentation. When comparing radiation treatment plans designed from physician-defined tumor volumes with treatment plans developed from the modified segmentation results, the reference target volume was irradiated within the same level of conformity. Analysis of the plans based on post

  19. A Model of Population and Subject (MOPS) Intensities with Application to Multiple Sclerosis Lesion Segmentation

    PubMed Central

    Tomas-Fernandez, Xavier; Warfield, Simon K.

    2015-01-01

    White matter (WM) lesions are thought to play an important role in multiple sclerosis (MS) disease burden. Recent work in the automated segmentation of white matter lesions from MRI has utilized a model in which lesions are outliers in the distribution of tissue signal intensities across the entire brain of each patient. However, the sensitivity and specificity of lesion detection and segmentation with these approaches have been inadequate. In our analysis, we determined this is due to the substantial overlap between the whole brain signal intensity distribution of lesions and normal tissue. Inspired by the ability of experts to detect lesions based on their local signal intensity characteristics, we propose a new algorithm that achieves lesion and brain tissue segmentation through simultaneous estimation of a spatially global within-the-subject intensity distribution and a spatially local intensity distribution derived from a healthy reference population. We demonstrate that MS lesions can be segmented as outliers from this intensity model of population and subject (MOPS). We carried out extensive experiments with both synthetic and clinical data, and compared the performance of our new algorithm to those of state-of-the art techniques. We found this new approach leads to a substantial improvement in the sensitivity and specificity of lesion detection and segmentation. PMID:25616008

  20. Segmentation-based method incorporating fractional volume analysis for quantification of brain atrophy on magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Wang, Deming; Doddrell, David M.

    2001-07-01

    Partial volume effect is a major problem in brain tissue segmentation on digital images such as magnetic resonance (MR) images. In this paper, special attention has been paid to partial volume effect when developing a method for quantifying brain atrophy. Specifically, partial volume effect is minimized in the process of parameter estimation prior to segmentation by identifying and excluding those voxels with possible partial volume effect. A quantitative measure for partial volume effect was also introduced through developing a model that calculates fractional volumes for voxels with mixtures of two different tissues. For quantifying cerebrospinal fluid (CSF) volumes, fractional volumes are calculated for two classes of mixture involving gray matter and CSF, and white matter and CSF. Tissue segmentation is carried out using 1D and 2D thresholding techniques after images are intensity- corrected. Threshold values are estimated using the minimum error method. Morphological processing and region identification analysis are used extensively in the algorithm. As an application, the method was employed for evaluating rates of brain atrophy based on serially acquired structural brain MR images. Consistent and accurate rates of brain atrophy have been obtained for patients with Alzheimer's disease as well as for elderly subjects due to normal aging process.

  1. Three-dimensional segmentation of pulmonary artery volume from thoracic computed tomography imaging

    NASA Astrophysics Data System (ADS)

    Lindenmaier, Tamas J.; Sheikh, Khadija; Bluemke, Emma; Gyacskov, Igor; Mura, Marco; Licskai, Christopher; Mielniczuk, Lisa; Fenster, Aaron; Cunningham, Ian A.; Parraga, Grace

    2015-03-01

    Chronic obstructive pulmonary disease (COPD), is a major contributor to hospitalization and healthcare costs in North America. While the hallmark of COPD is airflow limitation, it is also associated with abnormalities of the cardiovascular system. Enlargement of the pulmonary artery (PA) is a morphological marker of pulmonary hypertension, and was previously shown to predict acute exacerbations using a one-dimensional diameter measurement of the main PA. We hypothesized that a three-dimensional (3D) quantification of PA size would be more sensitive than 1D methods and encompass morphological changes along the entire central pulmonary artery. Hence, we developed a 3D measurement of the main (MPA), left (LPA) and right (RPA) pulmonary arteries as well as total PA volume (TPAV) from thoracic CT images. This approach incorporates segmentation of pulmonary vessels in cross-section for the MPA, LPA and RPA to provide an estimate of their volumes. Three observers performed five repeated measurements for 15 ex-smokers with ≥10 pack-years, and randomly identified from a larger dataset of 199 patients. There was a strong agreement (r2=0.76) for PA volume and PA diameter measurements, which was used as a gold standard. Observer measurements were strongly correlated and coefficients of variation for observer 1 (MPA:2%, LPA:3%, RPA:2%, TPA:2%) were not significantly different from observer 2 and 3 results. In conclusion, we generated manual 3D pulmonary artery volume measurements from thoracic CT images that can be performed with high reproducibility. Future work will involve automation for implementation in clinical workflows.

  2. 50 CFR 226.223 - Critical habitat for the Northwest Atlantic Ocean Distinct Population Segment of the loggerhead...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Critical habitat for the Northwest... the Northwest Atlantic Ocean Distinct Population Segment of the loggerhead sea turtle (Caretta caretta). Critical habitat is designated for the Northwest Atlantic Ocean Distinct Population Segment of...

  3. Extracellular and intracellular volume variations during postural change measured by segmental and wrist-ankle bioimpedance spectroscopy.

    PubMed

    Fenech, Marianne; Jaffrin, Michel Y

    2004-01-01

    Extracellular (ECW) and intracellular (ICW) volumes were measured using both segmental and wrist-ankle (W-A) bioimpedance spectroscopy (5-1000 kHz) in 15 healthy subjects (7 men, 8 women). In the 1st protocol, the subject, after sitting for 30 min, laid supine for at least 30 min. In the second protocol, the subject, who had been supine for 1 hr, sat up in bed for 10 min and returned to supine position for another hour. Segmental ECW and ICW resistances of legs, arms and trunk were measured by placing four voltage electrodes on wrist, shoulder, top of thigh and ankle and using Hanai's conductivity theory. W-A resistances were found to be very close to the sum of segmental resistances. When switching from sitting to supine (protocol 1), the mean ECW leg resistance increased by 18.2%, that of arm and W-A by 12.4%. Trunk resistance also increased but not significantly by 4.8%. Corresponding increases in ICW resistance were smaller for legs (3.7%) and arm (-0.7%) but larger for the trunk (21.4%). Total body ECW volumes from segmental measurements were in good agreement with W-A and Watson anthropomorphic correlation. The decrease in total ECW volume (when supine) calculated from segmental resistances was at 0.79 l less than the W-A one (1.12 l). Total ICW volume reductions were 3.4% (segmental) and 3.8% (W-A). Tests of protocol 2 confirmed that resistance and fluid volume values were not affected by a temporary position change. PMID:14723506

  4. Education, Work and Employment--Volume II. Segmented Labour Markets, Workplace Democracy and Educational Planning, Education and Self-Employment.

    ERIC Educational Resources Information Center

    Carnoy, Martin; And Others

    This volume contains three studies covering separate yet complementary aspects of the problem of the relationships between the educational system and the production system as manpower user. The first monograph on the theories of the markets seeks to answer two questions: what can be learned from the work done on the segmentation of the labor…

  5. Bayesian time series analysis of segments of the Rocky Mountain trumpeter swan population

    USGS Publications Warehouse

    Wright, Christopher K.; Sojda, Richard S.; Goodman, Daniel

    2002-01-01

    A Bayesian time series analysis technique, the dynamic linear model, was used to analyze counts of Trumpeter Swans (Cygnus buccinator) summering in Idaho, Montana, and Wyoming from 1931 to 2000. For the Yellowstone National Park segment of white birds (sub-adults and adults combined) the estimated probability of a positive growth rate is 0.01. The estimated probability of achieving the Subcommittee on Rocky Mountain Trumpeter Swans 2002 population goal of 40 white birds for the Yellowstone segment is less than 0.01. Outside of Yellowstone National Park, Wyoming white birds are estimated to have a 0.79 probability of a positive growth rate with a 0.05 probability of achieving the 2002 objective of 120 white birds. In the Centennial Valley in southwest Montana, results indicate a probability of 0.87 that the white bird population is growing at a positive rate with considerable uncertainty. The estimated probability of achieving the 2002 Centennial Valley objective of 160 white birds is 0.14 but under an alternative model falls to 0.04. The estimated probability that the Targhee National Forest segment of white birds has a positive growth rate is 0.03. In Idaho outside of the Targhee National Forest, white birds are estimated to have a 0.97 probability of a positive growth rate with a 0.18 probability of attaining the 2002 goal of 150 white birds.

  6. Segmenting CT prostate images using population and patient-specific statistics for radiotherapy

    SciTech Connect

    Feng, Qianjin; Foskey, Mark; Chen Wufan; Shen Dinggang

    2010-08-15

    Purpose: In the segmentation of sequential treatment-time CT prostate images acquired in image-guided radiotherapy, accurately capturing the intrapatient variation of the patient under therapy is more important than capturing interpatient variation. However, using the traditional deformable-model-based segmentation methods, it is difficult to capture intrapatient variation when the number of samples from the same patient is limited. This article presents a new deformable model, designed specifically for segmenting sequential CT images of the prostate, which leverages both population and patient-specific statistics to accurately capture the intrapatient variation of the patient under therapy. Methods: The novelty of the proposed method is twofold: First, a weighted combination of gradient and probability distribution function (PDF) features is used to build the appearance model to guide model deformation. The strengths of each feature type are emphasized by dynamically adjusting the weight between the profile-based gradient features and the local-region-based PDF features during the optimization process. An additional novel aspect of the gradient-based features is that, to alleviate the effect of feature inconsistency in the regions of gas and bone adjacent to the prostate, the optimal profile length at each landmark is calculated by statistically investigating the intensity profile in the training set. The resulting gradient-PDF combined feature produces more accurate and robust segmentations than general gradient features. Second, an online learning mechanism is used to build shape and appearance statistics for accurately capturing intrapatient variation. Results: The performance of the proposed method was evaluated on 306 images of the 24 patients. Compared to traditional gradient features, the proposed gradient-PDF combination features brought 5.2% increment in the success ratio of segmentation (from 94.1% to 99.3%). To evaluate the effectiveness of online

  7. 76 FR 76386 - Endangered and Threatened Species; 5-Year Reviews for 4 Distinct Population Segments of Steelhead...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-07

    ... Pacific salmon ESUs and steelhead DPSs in California, Oregon, Washington, and Idaho (75 FR 13082). Both... Reviews for 4 Distinct Population Segments of Steelhead in California AGENCY: National Marine Fisheries... Viable Salmonid Population framework, which relies on evaluating four key population...

  8. Exploring Population Admixture Dynamics via Empirical and Simulated Genome-wide Distribution of Ancestral Chromosomal Segments

    PubMed Central

    Jin, Wenfei; Wang, Sijia; Wang, Haifeng; Jin, Li; Xu, Shuhua

    2012-01-01

    The processes of genetic admixture determine the haplotype structure and linkage disequilibrium patterns of the admixed population, which is important for medical and evolutionary studies. However, most previous studies do not consider the inherent complexity of admixture processes. Here we proposed two approaches to explore population admixture dynamics, and we demonstrated, by analyzing genome-wide empirical and simulated data, that the approach based on the distribution of chromosomal segments of distinct ancestry (CSDAs) was more powerful than that based on the distribution of individual ancestry proportions. Analysis of 1,890 African Americans showed that a continuous gene flow model, in which the African American population continuously received gene flow from European populations over about 14 generations, best explained the admixture dynamics of African Americans among several putative models. Interestingly, we observed that some African Americans had much more European ancestry than the simulated samples, indicating substructures of local ancestries in African Americans that could have been caused by individuals from some particular lineages having repeatedly admixed with people of European ancestry. In contrast, the admixture dynamics of Mexicans could be explained by a gradual admixture model in which the Mexican population continuously received gene flow from both European and Amerindian populations over about 24 generations. Our results also indicated that recent gene flows from Sub-Saharan Africans have contributed to the gene pool of Middle Eastern populations such as Mozabite, Bedouin, and Palestinian. In summary, this study not only provides approaches to explore population admixture dynamics, but also advances our understanding on population history of African Americans, Mexicans, and Middle Eastern populations. PMID:23103229

  9. A region growing method for tumor volume segmentation on PET images for rectal and anal cancer patients.

    PubMed

    Day, Ellen; Betler, James; Parda, David; Reitz, Bodo; Kirichenko, Alexander; Mohammadi, Seyed; Miften, Moyed

    2009-10-01

    The application of automated segmentation methods for tumor delineation on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) images presents an opportunity to reduce the interobserver variability in radiotherapy (RT) treatment planning. In this work, three segmentation methods were evaluated and compared for rectal and anal cancer patients: (i) Percentage of the maximum standardized uptake value (SUV% max), (ii) fixed SUV cutoff of 2.5 (SUV2.5), and (iii) mathematical technique based on a confidence connected region growing (CCRG) method. A phantom study was performed to determine the SUV% max threshold value and found to be 43%, SUV43% max. The CCRG method is an iterative scheme that relies on the use of statistics from a specified region in the tumor. The scheme is initialized by a subregion of pixels surrounding the maximum intensity pixel. The mean and standard deviation of this region are measured and the pixels connected to the region are included or not based on the criterion that they are greater than a value derived from the mean and standard deviation. The mean and standard deviation of this new region are then measured and the process repeats. FDG-PET-CT imaging studies for 18 patients who received RT were used to evaluate the segmentation methods. A PET avid (PETavid) region was manually segmented for each patient and the volume was then used to compare the calculated volumes along with the absolute mean difference and range for all methods. For the SUV43% max method, the volumes were always smaller than the PETavid volume by a mean of 56% and a range of 21%-79%. The volumes from the SUV2.5 method were either smaller or larger than the PETavid volume by a mean of 37% and a range of 2%-130%. The CCRG approach provided the best results with a mean difference of 9% and a range of 1%-27%. Results show that the CCRG technique can be used in the segmentation of tumor volumes on FDG-PET images, thus providing treatment planners with a clinically

  10. Three-dimensional choroidal segmentation in spectral OCT volumes using optic disc prior information

    NASA Astrophysics Data System (ADS)

    Hu, Zhihong; Girkin, Christopher A.; Hariri, Amirhossein; Sadda, SriniVas R.

    2016-03-01

    Recently, much attention has been focused on determining the role of the peripapillary choroid - the layer between the outer retinal pigment epithelium (RPE)/Bruchs membrane (BM) and choroid-sclera (C-S) junction, whether primary or secondary in the pathogenesis of glaucoma. However, the automated choroidal segmentation in spectral-domain optical coherence tomography (SD-OCT) images of optic nerve head (ONH) has not been reported probably due to the fact that the presence of the BM opening (BMO, corresponding to the optic disc) can deflect the choroidal segmentation from its correct position. The purpose of this study is to develop a 3D graph-based approach to identify the 3D choroidal layer in ONH-centered SD-OCT images using the BMO prior information. More specifically, an initial 3D choroidal segmentation was first performed using the 3D graph search algorithm. Note that varying surface interaction constraints based on the choroidal morphological model were applied. To assist the choroidal segmentation, two other surfaces of internal limiting membrane and innerouter segment junction were also segmented. Based on the segmented layer between the RPE/BM and C-S junction, a 2D projection map was created. The BMO in the projection map was detected by a 2D graph search. The pre-defined BMO information was then incorporated into the surface interaction constraints of the 3D graph search to obtain more accurate choroidal segmentation. Twenty SD-OCT images from 20 healthy subjects were used. The mean differences of the choroidal borders between the algorithm and manual segmentation were at a sub-voxel level, indicating a high level segmentation accuracy.

  11. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    NASA Astrophysics Data System (ADS)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  12. Crop to wild introgression in lettuce: following the fate of crop genome segments in backcross populations

    PubMed Central

    2012-01-01

    Background After crop-wild hybridization, some of the crop genomic segments may become established in wild populations through selfing of the hybrids or through backcrosses to the wild parent. This constitutes a possible route through which crop (trans)genes could become established in natural populations. The likelihood of introgression of transgenes will not only be determined by fitness effects from the transgene itself but also by the crop genes linked to it. Although lettuce is generally regarded as self-pollinating, outbreeding does occur at a low frequency. Backcrossing to wild lettuce is a likely pathway to introgression along with selfing, due to the high frequency of wild individuals relative to the rarely occurring crop-wild hybrids. To test the effect of backcrossing on the vigour of inter-specific hybrids, Lactuca serriola, the closest wild relative of cultivated lettuce, was crossed with L. sativa and the F1 hybrid was backcrossed to L. serriola to generate BC1 and BC2 populations. Experiments were conducted on progeny from selfed plants of the backcrossing families (BC1S1 and BC2S1). Plant vigour of these two backcrossing populations was determined in the greenhouse under non-stress and abiotic stress conditions (salinity, drought, and nutrient deficiency). Results Despite the decreasing contribution of crop genomic blocks in the backcross populations, the BC1S1 and BC2S1 hybrids were characterized by a substantial genetic variation under both non-stress and stress conditions. Hybrids were identified that performed equally or better than the wild genotypes, indicating that two backcrossing events did not eliminate the effect of the crop genomic segments that contributed to the vigour of the BC1 and BC2 hybrids. QTLs for plant vigour under non-stress and the various stress conditions were detected in the two populations with positive as well as negative effects from the crop. Conclusion As it was shown that the crop contributed QTLs with either a

  13. Markov random field and Gaussian mixture for segmented MRI-based partial volume correction in PET.

    PubMed

    Bousse, Alexandre; Pedemonte, Stefano; Thomas, Benjamin A; Erlandsson, Kjell; Ourselin, Sébastien; Arridge, Simon; Hutton, Brian F

    2012-10-21

    In this paper we propose a segmented magnetic resonance imaging (MRI) prior-based maximum penalized likelihood deconvolution technique for positron emission tomography (PET) images. The model assumes the existence of activity classes that behave like a hidden Markov random field (MRF) driven by the segmented MRI. We utilize a mean field approximation to compute the likelihood of the MRF. We tested our method on both simulated and clinical data (brain PET) and compared our results with PET images corrected with the re-blurred Van Cittert (VC) algorithm, the simplified Guven (SG) algorithm and the region-based voxel-wise (RBV) technique. We demonstrated our algorithm outperforms the VC algorithm and outperforms SG and RBV corrections when the segmented MRI is inconsistent (e.g. mis-segmentation, lesions, etc) with the PET image.

  14. Hierarchical spatial genetic structure in a distinct population segment of greater sage-grouse

    USGS Publications Warehouse

    Oyler-McCance, Sara J.; Casazza, Michael L.; Fike, Jennifer A.; Coates, Peter S.

    2014-01-01

    Greater sage-grouse (Centrocercus urophasianus) within the Bi-State Management Zone (area along the border between Nevada and California) are geographically isolated on the southwestern edge of the species’ range. Previous research demonstrated that this population is genetically unique, with a high proportion of unique mitochondrial DNA (mtDNA) haplotypes and with significant differences in microsatellite allele frequencies compared to populations across the species’ range. As a result, this population was considered a distinct population segment (DPS) and was recently proposed for listing as threatened under the U.S. Endangered Species Act. A more comprehensive understanding of the boundaries of this genetically unique population (where the Bi-State population begins) and an examination of genetic structure within the Bi-State is needed to help guide effective management decisions. We collected DNA from eight sampling locales within the Bi-State (N = 181) and compared those samples to previously collected DNA from the two most proximal populations outside of the Bi-State DPS, generating mtDNA sequence data and amplifying 15 nuclear microsatellites. Both mtDNA and microsatellite analyses support the idea that the Bi-State DPS represents a genetically unique population, which has likely been separated for thousands of years. Seven mtDNA haplotypes were found exclusively in the Bi-State population and represented 73 % of individuals, while three haplotypes were shared with neighboring populations. In the microsatellite analyses both STRUCTURE and FCA separate the Bi-State from the neighboring populations. We also found genetic structure within the Bi-State as both types of data revealed differences between the northern and southern part of the Bi-State and there was evidence of isolation-by-distance. STRUCTURE revealed three subpopulations within the Bi-State consisting of the northern Pine Nut Mountains (PNa), mid Bi-State, and White Mountains (WM) following a

  15. A novel approach for the automated segmentation and volume quantification of cardiac fats on computed tomography.

    PubMed

    Rodrigues, É O; Morais, F F C; Morais, N A O S; Conci, L S; Neto, L V; Conci, A

    2016-01-01

    The deposits of fat on the surroundings of the heart are correlated to several health risk factors such as atherosclerosis, carotid stiffness, coronary artery calcification, atrial fibrillation and many others. These deposits vary unrelated to obesity, which reinforces its direct segmentation for further quantification. However, manual segmentation of these fats has not been widely deployed in clinical practice due to the required human workload and consequential high cost of physicians and technicians. In this work, we propose a unified method for an autonomous segmentation and quantification of two types of cardiac fats. The segmented fats are termed epicardial and mediastinal, and stand apart from each other by the pericardium. Much effort was devoted to achieve minimal user intervention. The proposed methodology mainly comprises registration and classification algorithms to perform the desired segmentation. We compare the performance of several classification algorithms on this task, including neural networks, probabilistic models and decision tree algorithms. Experimental results of the proposed methodology have shown that the mean accuracy regarding both epicardial and mediastinal fats is 98.5% (99.5% if the features are normalized), with a mean true positive rate of 98.0%. In average, the Dice similarity index was equal to 97.6%. PMID:26474835

  16. An interactive system for volume segmentation in computer-assisted surgery

    NASA Astrophysics Data System (ADS)

    Kunert, Tobias; Heimann, Tobias; Schroter, Andre; Schobinger, Max; Bottger, Thomas; Thorn, Matthias; Wolf, Ivo; Engelmann, Uwe; Meinzer, Hans-Peter

    2004-05-01

    Computer-assisted surgery aims at a decreased surgical risk and a reduced recovery time of patients. However, its use is still limited to complex cases because of the high effort. It is often caused by the extensive medical image analysis. Especially, image segmentation requires a lot of manual work. Surgeons and radiologists are suffering from usability problems of many workstations. In this work, we present a dedicated workplace for interactive segmentation integratd within the CHILI (tele-)radiology system. The software comes with a lot of improvements with respect to its graphical user interface, the segmentation process and the segmentatin methods. We point out important software requirements and give insight into the concepts which were implemented. Further examples and applications illustrate the software system.

  17. Performance evaluation of automated segmentation software on optical coherence tomography volume data.

    PubMed

    Tian, Jing; Varga, Boglarka; Tatrai, Erika; Fanni, Palya; Somfai, Gabor Mark; Smiddy, William E; Debuc, Delia Cabrera

    2016-05-01

    Over the past two decades a significant number of OCT segmentation approaches have been proposed in the literature. Each methodology has been conceived for and/or evaluated using specific datasets that do not reflect the complexities of the majority of widely available retinal features observed in clinical settings. In addition, there does not exist an appropriate OCT dataset with ground truth that reflects the realities of everyday retinal features observed in clinical settings. While the need for unbiased performance evaluation of automated segmentation algorithms is obvious, the validation process of segmentation algorithms have been usually performed by comparing with manual labelings from each study and there has been a lack of common ground truth. Therefore, a performance comparison of different algorithms using the same ground truth has never been performed. This paper reviews research-oriented tools for automated segmentation of the retinal tissue on OCT images. It also evaluates and compares the performance of these software tools with a common ground truth.

  18. SU-E-J-238: Monitoring Lymph Node Volumes During Radiotherapy Using Semi-Automatic Segmentation of MRI Images

    SciTech Connect

    Veeraraghavan, H; Tyagi, N; Riaz, N; McBride, S; Lee, N; Deasy, J

    2014-06-01

    Purpose: Identification and image-based monitoring of lymph nodes growing due to disease, could be an attractive alternative to prophylactic head and neck irradiation. We evaluated the accuracy of the user-interactive Grow Cut algorithm for volumetric segmentation of radiotherapy relevant lymph nodes from MRI taken weekly during radiotherapy. Method: The algorithm employs user drawn strokes in the image to volumetrically segment multiple structures of interest. We used a 3D T2-wturbo spin echo images with an isotropic resolution of 1 mm3 and FOV of 492×492×300 mm3 of head and neck cancer patients who underwent weekly MR imaging during the course of radiotherapy. Various lymph node (LN) levels (N2, N3, N4'5) were individually contoured on the weekly MR images by an expert physician and used as ground truth in our study. The segmentation results were compared with the physician drawn lymph nodes based on DICE similarity score. Results: Three head and neck patients with 6 weekly MR images were evaluated. Two patients had level 2 LN drawn and one patient had level N2, N3 and N4'5 drawn on each MR image. The algorithm took an average of a minute to segment the entire volume (512×512×300 mm3). The algorithm achieved an overall DICE similarity score of 0.78. The time taken for initializing and obtaining the volumetric mask was about 5 mins for cases with only N2 LN and about 15 mins for the case with N2,N3 and N4'5 level nodes. The longer initialization time for the latter case was due to the need for accurate user inputs to separate overlapping portions of the different LN. The standard deviation in segmentation accuracy at different time points was utmost 0.05. Conclusions: Our initial evaluation of the grow cut segmentation shows reasonably accurate and consistent volumetric segmentations of LN with minimal user effort and time.

  19. Linear test bed. Volume 1: Test bed no. 1. [aerospike test bed with segmented combustor

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Linear Test Bed program was to design, fabricate, and evaluation test an advanced aerospike test bed which employed the segmented combustor concept. The system is designated as a linear aerospike system and consists of a thrust chamber assembly, a power package, and a thrust frame. It was designed as an experimental system to demonstrate the feasibility of the linear aerospike-segmented combustor concept. The overall dimensions are 120 inches long by 120 inches wide by 96 inches in height. The propellants are liquid oxygen/liquid hydrogen. The system was designed to operate at 1200-psia chamber pressure, at a mixture ratio of 5.5. At the design conditions, the sea level thrust is 200,000 pounds. The complete program including concept selection, design, fabrication, component test, system test, supporting analysis and posttest hardware inspection is described.

  20. NSEG, a segmented mission analysis program for low and high speed aircraft. Volume 1: Theoretical development

    NASA Technical Reports Server (NTRS)

    Hague, D. S.; Rozendaal, H. L.

    1977-01-01

    A rapid mission analysis code based on the use of approximate flight path equations of motion is presented. Equation form varies with the segment type, for example, accelerations, climbs, cruises, descents, and decelerations. Realistic and detailed characteristics were specified in tabular form. The code also contains extensive flight envelope performance mapping capabilities. Approximate take off and landing analyses were performed. At high speeds, centrifugal lift effects were accounted for. Extensive turbojet and ramjet engine scaling procedures were incorporated in the code.

  1. Application of taxonomy theory, Volume 1: Computing a Hopf bifurcation-related segment of the feasibility boundary. Final report

    SciTech Connect

    Zaborszky, J.; Venkatasubramanian, V.

    1995-10-01

    Taxonomy Theory is the first precise comprehensive theory for large power system dynamics modeled in any detail. The motivation for this project is to show that it can be used, practically, for analyzing a disturbance that actually occurred on a large system, which affected a sizable portion of the Midwest with supercritical Hopf type oscillations. This event is well documented and studied. The report first summarizes Taxonomy Theory with an engineering flavor. Then various computational approaches are sighted and analyzed for desirability to use with Taxonomy Theory. Then working equations are developed for computing a segment of the feasibility boundary that bounds the region of (operating) parameters throughout which the operating point can be moved without losing stability. Then experimental software incorporating large EPRI software packages PSAPAC is developed. After a summary of the events during the subject disturbance, numerous large scale computations, up to 7600 buses, are reported. These results are reduced into graphical and tabular forms, which then are analyzed and discussed. The report is divided into two volumes. This volume illustrates the use of the Taxonomy Theory for computing the feasibility boundary and presents evidence that the event indeed led to a Hopf type oscillation on the system. Furthermore it proves that the Feasibility Theory can indeed be used for practical computation work with very large systems. Volume 2, a separate volume, will show that the disturbance has led to a supercritical (that is stable oscillation) Hopf bifurcation.

  2. Bibliography of Family Planning and Population, Volume 1 Number 3.

    ERIC Educational Resources Information Center

    Linzell, Dinah, Comp.

    Compiled from the world's research literature, this bi-monthly classified list of references on population and family planning emphasizes recently published material, primarily journal literature. Topics covered include: population and fertility; reproductive behaviour; the family; education in population, family planning, and sex; family…

  3. Interchange. Population Education Newsletter. Volume 5, Number 3.

    ERIC Educational Resources Information Center

    Seltzer, Judith; Fletcher, Carol

    This publication is designed to introduce the interdisciplinary nature of population information to educators and centers of population education activity, provide classroom activity suggestions, and to review developments in the effort to infuse population issues into U.S. secondary schools. The publication provides a forum for information and…

  4. Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers

    PubMed Central

    Yamada, Yosuke; Yamashita, Daichi; Yamamoto, Shinji; Matsui, Tomoyuki; Seo, Kazuya; Azuma, Yoshikazu; Kida, Yoshikazu; Morihara, Toru; Kimura, Misaka

    2013-01-01

    The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important. PMID:24379713

  5. Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers.

    PubMed

    Yamada, Yosuke; Yamashita, Daichi; Yamamoto, Shinji; Matsui, Tomoyuki; Seo, Kazuya; Azuma, Yoshikazu; Kida, Yoshikazu; Morihara, Toru; Kimura, Misaka

    2013-01-01

    The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important. PMID:24379713

  6. Whole-body and segmental muscle volume are associated with ball velocity in high school baseball pitchers.

    PubMed

    Yamada, Yosuke; Yamashita, Daichi; Yamamoto, Shinji; Matsui, Tomoyuki; Seo, Kazuya; Azuma, Yoshikazu; Kida, Yoshikazu; Morihara, Toru; Kimura, Misaka

    2013-01-01

    The aim of the study was to examine the relationship between pitching ball velocity and segmental (trunk, upper arm, forearm, upper leg, and lower leg) and whole-body muscle volume (MV) in high school baseball pitchers. Forty-seven male high school pitchers (40 right-handers and seven left-handers; age, 16.2 ± 0.7 years; stature, 173.6 ± 4.9 cm; mass, 65.0 ± 6.8 kg, years of baseball experience, 7.5 ± 1.8 years; maximum pitching ball velocity, 119.0 ± 9.0 km/hour) participated in the study. Segmental and whole-body MV were measured using segmental bioelectrical impedance analysis. Maximum ball velocity was measured with a sports radar gun. The MV of the dominant arm was significantly larger than the MV of the non-dominant arm (P < 0.001). There was no difference in MV between the dominant and non-dominant legs. Whole-body MV was significantly correlated with ball velocity (r = 0.412, P < 0.01). Trunk MV was not correlated with ball velocity, but the MV for both lower legs, and the dominant upper leg, upper arm, and forearm were significantly correlated with ball velocity (P < 0.05). The results were not affected by age or years of baseball experience. Whole-body and segmental MV are associated with ball velocity in high school baseball pitchers. However, the contribution of the muscle mass on pitching ball velocity is limited, thus other fundamental factors (ie, pitching skill) are also important.

  7. Atlas-Based Segmentation Improves Consistency and Decreases Time Required for Contouring Postoperative Endometrial Cancer Nodal Volumes

    SciTech Connect

    Young, Amy V.; Wortham, Angela; Wernick, Iddo; Evans, Andrew; Ennis, Ronald D.

    2011-03-01

    Purpose: Accurate target delineation of the nodal volumes is essential for three-dimensional conformal and intensity-modulated radiotherapy planning for endometrial cancer adjuvant therapy. We hypothesized that atlas-based segmentation ('autocontouring') would lead to time savings and more consistent contours among physicians. Methods and Materials: A reference anatomy atlas was constructed using the data from 15 postoperative endometrial cancer patients by contouring the pelvic nodal clinical target volume on the simulation computed tomography scan according to the Radiation Therapy Oncology Group 0418 trial using commercially available software. On the simulation computed tomography scans from 10 additional endometrial cancer patients, the nodal clinical target volume autocontours were generated. Three radiation oncologists corrected the autocontours and delineated the manual nodal contours under timed conditions while unaware of the other contours. The time difference was determined, and the overlap of the contours was calculated using Dice's coefficient. Results: For all physicians, manual contouring of the pelvic nodal target volumes and editing the autocontours required a mean {+-} standard deviation of 32 {+-} 9 vs. 23 {+-} 7 minutes, respectively (p = .000001), a 26% time savings. For each physician, the time required to delineate the manual contours vs. correcting the autocontours was 30 {+-} 3 vs. 21 {+-} 5 min (p = .003), 39 {+-} 12 vs. 30 {+-} 5 min (p = .055), and 29 {+-} 5 vs. 20 {+-} 5 min (p = .0002). The mean overlap increased from manual contouring (0.77) to correcting the autocontours (0.79; p = .038). Conclusion: The results of our study have shown that autocontouring leads to increased consistency and time savings when contouring the nodal target volumes for adjuvant treatment of endometrial cancer, although the autocontours still required careful editing to ensure that the lymph nodes at risk of recurrence are properly included in the target

  8. Prioritization of brain MRI volumes using medical image perception model and tumor region segmentation.

    PubMed

    Mehmood, Irfan; Ejaz, Naveed; Sajjad, Muhammad; Baik, Sung Wook

    2013-10-01

    The objective of the present study is to explore prioritization methods in diagnostic imaging modalities to automatically determine the contents of medical images. In this paper, we propose an efficient prioritization of brain MRI. First, the visual perception of the radiologists is adapted to identify salient regions. Then this saliency information is used as an automatic label for accurate segmentation of brain lesion to determine the scientific value of that image. The qualitative and quantitative results prove that the rankings generated by the proposed method are closer to the rankings created by radiologists. PMID:24034739

  9. Simultaneous segmentation of retinal surfaces and microcystic macular edema in SDOCT volumes

    NASA Astrophysics Data System (ADS)

    Antony, Bhavna J.; Lang, Andrew; Swingle, Emily K.; Al-Louzi, Omar; Carass, Aaron; Solomon, Sharon; Calabresi, Peter A.; Saidha, Shiv; Prince, Jerry L.

    2016-03-01

    Optical coherence tomography (OCT) is a noninvasive imaging modality that has begun to find widespread use in retinal imaging for the detection of a variety of ocular diseases. In addition to structural changes in the form of altered retinal layer thicknesses, pathological conditions may also cause the formation of edema within the retina. In multiple sclerosis, for instance, the nerve fiber and ganglion cell layers are known to thin. Additionally, the formation of pseudocysts called microcystic macular edema (MME) have also been observed in the eyes of about 5% of MS patients, and its presence has been shown to be correlated with disease severity. Previously, we proposed separate algorithms for the segmentation of retinal layers and MME, but since MME mainly occurs within specific regions of the retina, a simultaneous approach is advantageous. In this work, we propose an automated globally optimal graph-theoretic approach that simultaneously segments the retinal layers and the MME in volumetric OCT scans. SD-OCT scans from one eye of 12 MS patients with known MME and 8 healthy controls were acquired and the pseudocysts manually traced. The overall precision and recall of the pseudocyst detection was found to be 86.0% and 79.5%, respectively.

  10. Normative Data for Body Segment Weights, Volumes, and Densities in Cadaver and Living Subjects

    ERIC Educational Resources Information Center

    Gold, Ellen; Katch, Victor

    1976-01-01

    Application of only Dempster's data on problems in human motion studies to living subjects is at best a rough approximation, in light of apparent differences between Dempster's data and the grand mean calculated for all data, with respect to volume and weight. (MB)

  11. Semiautomated three-dimensional segmentation software to quantify carpal bone volume changes on wrist CT scans for arthritis assessment.

    PubMed

    Duryea, J; Magalnick, M; Alli, S; Yao, L; Wilson, M; Goldbach-Mansky, R

    2008-06-01

    Rapid progression of joint destruction is an indication of poor prognosis in patients with rheumatoid arthritis. Computed tomography (CT) has the potential to serve as a gold standard for joint imaging since it provides high resolution three-dimensional (3D) images of bone structure. The authors have developed a method to quantify erosion volume changes on wrist CT scans. In this article they present a description and validation of the methodology using multiple scans of a hand phantom and five human subjects. An anthropomorphic hand phantom was imaged with a clinical CT scanner at three different orientations separated by a 30-deg angle. A reader used the semiautomated software tool to segment the individual carpal bones of each CT scan. Reproducibility was measured as the root-mean-square standard deviation (RMMSD) and coefficient of variation (CoV) between multiple measurements of the carpal volumes. Longitudinal erosion progression was studied by inserting simulated erosions in a paired second scan. The change in simulated erosion size was calculated by performing 3D image registration and measuring the volume difference between scans in a region adjacent to the simulated erosion. The RMSSD for the total carpal volumes was 21.0 mm3 (CoV = 1.3%) for the phantom, and 44.1 mm3 (CoV = 3.0%) for the in vivo subjects. Using 3D registration and local volume difference calculations, the RMMSD was 1.0-3.0 mm3 The reader time was approximately 5 min per carpal bone. There was excellent agreement between the measured and simulated erosion volumes. The effect of a poorly measured volume for a single erosion is mitigated by the large number of subjects that would comprise a clinical study and that there will be many erosions measured per patient. CT promises to be a quantifiable tool to measure erosion volumes and may serve as a gold standard that can be used in the validation of other modalities such as magnetic resonance imaging.

  12. NSEG: A segmented mission analysis program for low and high speed aircraft. Volume 3: Demonstration problems

    NASA Technical Reports Server (NTRS)

    Hague, D. S.; Rozendaal, H. L.

    1977-01-01

    Program NSEG is a rapid mission analysis code based on the use of approximate flight path equations of motion. Equation form varies with the segment type, for example, accelerations, climbs, cruises, descents, and decelerations. Realistic and detailed vehicle characteristics are specified in tabular form. In addition to its mission performance calculation capabilities, the code also contains extensive flight envelope performance mapping capabilities. For example, rate-of-climb, turn rates, and energy maneuverability parameter values may be mapped in the Mach-altitude plane. Approximate take off and landing analyses are also performed. At high speeds, centrifugal lift effects are accounted for. Extensive turbojet and ramjet engine scaling procedures are incorporated in the code.

  13. 4-D segmentation and normalization of 3He MR images for intrasubject assessment of ventilated lung volumes

    NASA Astrophysics Data System (ADS)

    Contrella, Benjamin; Tustison, Nicholas J.; Altes, Talissa A.; Avants, Brian B.; Mugler, John P., III; de Lange, Eduard E.

    2012-03-01

    Although 3He MRI permits compelling visualization of the pulmonary air spaces, quantitation of absolute ventilation is difficult due to confounds such as field inhomogeneity and relative intensity differences between image acquisition; the latter complicating longitudinal investigations of ventilation variation with respiratory alterations. To address these potential difficulties, we present a 4-D segmentation and normalization approach for intra-subject quantitative analysis of lung hyperpolarized 3He MRI. After normalization, which combines bias correction and relative intensity scaling between longitudinal data, partitioning of the lung volume time series is performed by iterating between modeling of the combined intensity histogram as a Gaussian mixture model and modulating the spatial heterogeneity tissue class assignments through Markov random field modeling. Evaluation of the algorithm was retrospectively applied to a cohort of 10 asthmatics between 19-25 years old in which spirometry and 3He MR ventilation images were acquired both before and after respiratory exacerbation by a bronchoconstricting agent (methacholine). Acquisition was repeated under the same conditions from 7 to 467 days (mean +/- standard deviation: 185 +/- 37.2) later. Several techniques were evaluated for matching intensities between the pre and post-methacholine images with the 95th percentile value histogram matching demonstrating superior correlations with spirometry measures. Subsequent analysis evaluated segmentation parameters for assessing ventilation change in this cohort. Current findings also support previous research that areas of poor ventilation in response to bronchoconstriction are relatively consistent over time.

  14. Inter-sport variability of muscle volume distribution identified by segmental bioelectrical impedance analysis in four ball sports

    PubMed Central

    Yamada, Yosuke; Masuo, Yoshihisa; Nakamura, Eitaro; Oda, Shingo

    2013-01-01

    The aim of this study was to evaluate and quantify differences in muscle distribution in athletes of various ball sports using segmental bioelectrical impedance analysis (SBIA). Participants were 115 male collegiate athletes from four ball sports (baseball, soccer, tennis, and lacrosse). Percent body fat (%BF) and lean body mass were measured, and SBIA was used to measure segmental muscle volume (MV) in bilateral upper arms, forearms, thighs, and lower legs. We calculated the MV ratios of dominant to nondominant, proximal to distal, and upper to lower limbs. The measurements consisted of a total of 31 variables. Cluster and factor analyses were applied to identify redundant variables. The muscle distribution was significantly different among groups, but the %BF was not. The classification procedures of the discriminant analysis could correctly distinguish 84.3% of the athletes. These results suggest that collegiate ball game athletes have adapted their physique to their sport movements very well, and the SBIA, which is an affordable, noninvasive, easy-to-operate, and fast alternative method in the field, can distinguish ball game athletes according to their specific muscle distribution within a 5-minute measurement. The SBIA could be a useful, affordable, and fast tool for identifying talents for specific sports. PMID:24379714

  15. Inter-sport variability of muscle volume distribution identified by segmental bioelectrical impedance analysis in four ball sports.

    PubMed

    Yamada, Yosuke; Masuo, Yoshihisa; Nakamura, Eitaro; Oda, Shingo

    2013-01-01

    The aim of this study was to evaluate and quantify differences in muscle distribution in athletes of various ball sports using segmental bioelectrical impedance analysis (SBIA). Participants were 115 male collegiate athletes from four ball sports (baseball, soccer, tennis, and lacrosse). Percent body fat (%BF) and lean body mass were measured, and SBIA was used to measure segmental muscle volume (MV) in bilateral upper arms, forearms, thighs, and lower legs. We calculated the MV ratios of dominant to nondominant, proximal to distal, and upper to lower limbs. The measurements consisted of a total of 31 variables. Cluster and factor analyses were applied to identify redundant variables. The muscle distribution was significantly different among groups, but the %BF was not. The classification procedures of the discriminant analysis could correctly distinguish 84.3% of the athletes. These results suggest that collegiate ball game athletes have adapted their physique to their sport movements very well, and the SBIA, which is an affordable, noninvasive, easy-to-operate, and fast alternative method in the field, can distinguish ball game athletes according to their specific muscle distribution within a 5-minute measurement. The SBIA could be a useful, affordable, and fast tool for identifying talents for specific sports.

  16. Prostate volume contouring: A 3D analysis of segmentation using 3DTRUS, CT, and MR

    SciTech Connect

    Smith, Wendy L. . E-mail: wendy.smith@cancerboard.ab.ca; Lewis, Craig |; Bauman, Glenn ||; Rodrigues, George ||; D'Souza, David |; Ash, Robert |; Ho, Derek; Venkatesan, Varagur |; Downey, Donal; Fenster, Aaron

    2007-03-15

    Purpose: This study evaluated the reproducibility and modality differences of prostate contouring after brachytherapy implant using three-dimensional (3D) transrectal ultrasound (3DTRUS), T2-weighted magnetic resonance (MR), and computed tomography (CT) imaging. Methods and Materials: Seven blinded observers contoured 10 patients' prostates, 30 day postimplant, on 3DTRUS, MR, and CT images to assess interobserver variability. Randomized images were contoured twice by each observer. We analyzed length and volume measurements and performed a 3D analysis of intra- and intermodality variation. Results: Average volume ratios were 1.16 for CT/MR, 0.90 for 3DTRUS/MR, and 1.30 for CT/3DTRUS. Overall contouring variability was largest for CT and similar for MR and 3DTRUS. The greatest variability of CT contours occurred at the posterior and anterior portions of the midgland. On MR, overall variability was smaller, with a maximum in the anterior region. On 3DTRUS, high variability occurred in anterior regions of the apex and base, whereas the prostate-rectum interface had the smallest variability. The shape of the prostate on MR was rounder, with the base and apex of similar size, whereas CT contours had broad, flat bases narrowing toward the apex. The average percent of surface area that was significantly different (95% confidence interval) for CT/MR was 4.1%; 3DTRUS/MR, 10.7%; and CT/3DTRUS, 6.3%. The larger variability of CT measurements made significant differences more difficult to detect. Conclusions: The contouring of prostates on CT, MR, and 3DTRUS results in systematic differences in the locations of and variability in prostate boundary definition between modalities. MR and 3DTRUS display the smallest variability and the closest correspondence.

  17. Interchange. Population Education Newsletter. Volume 1, Number 1.

    ERIC Educational Resources Information Center

    Population Reference Bureau, Inc., Washington, DC.

    This bi-monthly newsletter is designed to provide information to teachers, curriculum supervisors, and administrators on the most recent developments in the growing effort to introduce population issues into formal school curricula, primarily at the middle and secondary school levels. This initial issue summarizes the activities of 1971-1972…

  18. Calculation of population doses with RADTRAN for route segments that have an unpopulated near-field region

    SciTech Connect

    Kanipe, F.L.; Neuhauser, S.; Sprung, J.L.

    1998-03-01

    The RADTRAN code (Neuhauser and Kanipe, 1994) models the radiological consequences of the transportation of radioactive materials, both the exposures that will occur if the transport occurs without incident, and the exposures that may occur should the transport vehicle be involved in an accident while en route. Because accidents might occur at any point along a transportation route, RADTRAN divides the route into segments (links) and uses a uniform population density and constant meteorological conditions (wind speed and atmospheric stability) to represent the population and weather characteristics of each route segment. A way to perform RADTRAN calculations, that allows an unpopulated near-field region along a transportation link to be approximately modeled, is described, validated, and then illustratively applied to a coastal sailing route.

  19. Automated compromised right lung segmentation method using a robust atlas-based active volume model with sparse shape composition prior in CT.

    PubMed

    Zhou, Jinghao; Yan, Zhennan; Lasio, Giovanni; Huang, Junzhou; Zhang, Baoshe; Sharma, Navesh; Prado, Karl; D'Souza, Warren

    2015-12-01

    To resolve challenges in image segmentation in oncologic patients with severely compromised lung, we propose an automated right lung segmentation framework that uses a robust, atlas-based active volume model with a sparse shape composition prior. The robust atlas is achieved by combining the atlas with the output of sparse shape composition. Thoracic computed tomography images (n=38) from patients with lung tumors were collected. The right lung in each scan was manually segmented to build a reference training dataset against which the performance of the automated segmentation method was assessed. The quantitative results of this proposed segmentation method with sparse shape composition achieved mean Dice similarity coefficient (DSC) of (0.72, 0.81) with 95% CI, mean accuracy (ACC) of (0.97, 0.98) with 95% CI, and mean relative error (RE) of (0.46, 0.74) with 95% CI. Both qualitative and quantitative comparisons suggest that this proposed method can achieve better segmentation accuracy with less variance than other atlas-based segmentation methods in the compromised lung segmentation.

  20. 3D brain tumor segmentation in multimodal MR images based on learning population- and patient-specific feature sets.

    PubMed

    Jiang, Jun; Wu, Yao; Huang, Meiyan; Yang, Wei; Chen, Wufan; Feng, Qianjin

    2013-01-01

    Brain tumor segmentation is a clinical requirement for brain tumor diagnosis and radiotherapy planning. Automating this process is a challenging task due to the high diversity in appearance of tumor tissue among different patients and the ambiguous boundaries of lesions. In this paper, we propose a method to construct a graph by learning the population- and patient-specific feature sets of multimodal magnetic resonance (MR) images and by utilizing the graph-cut to achieve a final segmentation. The probabilities of each pixel that belongs to the foreground (tumor) and the background are estimated by global and custom classifiers that are trained through learning population- and patient-specific feature sets, respectively. The proposed method is evaluated using 23 glioma image sequences, and the segmentation results are compared with other approaches. The encouraging evaluation results obtained, i.e., DSC (84.5%), Jaccard (74.1%), sensitivity (87.2%), and specificity (83.1%), show that the proposed method can effectively make use of both population- and patient-specific information. PMID:23816459

  1. Total heart volume as a function of clinical and anthropometric parameters in a population of external beam radiation therapy patients

    NASA Astrophysics Data System (ADS)

    Nadège Ilembe Badouna, Audrey; Veres, Cristina; Haddy, Nadia; Bidault, François; Lefkopoulos, Dimitri; Chavaudra, Jean; Bridier, André; de Vathaire, Florent; Diallo, Ibrahima

    2012-01-01

    The aim of this paper was to determine anthropometric parameters leading to the least uncertain estimate of heart size when connecting a computational phantom to an external beam radiation therapy (EBRT) patient. From computed tomography images, we segmented the heart and calculated its total volume (THV) in a population of 270 EBRT patients of both sexes, aged 0.7-83 years. Our data were fitted using logistic growth functions. The patient age, height, weight, body mass index and body surface area (BSA) were used as explanatory variables. For both genders, good fits were obtained with both weight (R2 = 0.89 for males and 0.83 for females) and BSA (R2 = 0.90 for males and 0.84 for females). These results demonstrate that, among anthropometric parameters, weight plays an important role in predicting THV. These findings should be taken into account when assigning a computational phantom to a patient.

  2. Comparison of Acute and Chronic Traumatic Brain Injury Using Semi-Automatic Multimodal Segmentation of MR Volumes

    PubMed Central

    Chambers, Micah C.; Alger, Jeffry R.; Filippou, Maria; Prastawa, Marcel W.; Wang, Bo; Hovda, David A.; Gerig, Guido; Toga, Arthur W.; Kikinis, Ron; Vespa, Paul M.; Van Horn, John D.

    2011-01-01

    Abstract Although neuroimaging is essential for prompt and proper management of traumatic brain injury (TBI), there is a regrettable and acute lack of robust methods for the visualization and assessment of TBI pathophysiology, especially for of the purpose of improving clinical outcome metrics. Until now, the application of automatic segmentation algorithms to TBI in a clinical setting has remained an elusive goal because existing methods have, for the most part, been insufficiently robust to faithfully capture TBI-related changes in brain anatomy. This article introduces and illustrates the combined use of multimodal TBI segmentation and time point comparison using 3D Slicer, a widely-used software environment whose TBI data processing solutions are openly available. For three representative TBI cases, semi-automatic tissue classification and 3D model generation are performed to perform intra-patient time point comparison of TBI using multimodal volumetrics and clinical atrophy measures. Identification and quantitative assessment of extra- and intra-cortical bleeding, lesions, edema, and diffuse axonal injury are demonstrated. The proposed tools allow cross-correlation of multimodal metrics from structural imaging (e.g., structural volume, atrophy measurements) with clinical outcome variables and other potential factors predictive of recovery. In addition, the workflows described are suitable for TBI clinical practice and patient monitoring, particularly for assessing damage extent and for the measurement of neuroanatomical change over time. With knowledge of general location, extent, and degree of change, such metrics can be associated with clinical measures and subsequently used to suggest viable treatment options. PMID:21787171

  3. Integrating Girl Child Issues into Population Education: Strategies and Sample Curriculum and Instructional Materials. Volume 2.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand).

    One of the most important vehicles for promoting the concerns of the "girl child" and the elimination of gender bias is through education, and since programs in population education are being funded all over the world, population education is a suitable and effective medium for integrating messages on the girl child. This two-volume publication…

  4. Four-chamber heart modeling and automatic segmentation for 3-D cardiac CT volumes using marginal space learning and steerable features.

    PubMed

    Zheng, Yefeng; Barbu, Adrian; Georgescu, Bogdan; Scheuering, Michael; Comaniciu, Dorin

    2008-11-01

    We propose an automatic four-chamber heart segmentation system for the quantitative functional analysis of the heart from cardiac computed tomography (CT) volumes. Two topics are discussed: heart modeling and automatic model fitting to an unseen volume. Heart modeling is a nontrivial task since the heart is a complex nonrigid organ. The model must be anatomically accurate, allow manual editing, and provide sufficient information to guide automatic detection and segmentation. Unlike previous work, we explicitly represent important landmarks (such as the valves and the ventricular septum cusps) among the control points of the model. The control points can be detected reliably to guide the automatic model fitting process. Using this model, we develop an efficient and robust approach for automatic heart chamber segmentation in 3-D CT volumes. We formulate the segmentation as a two-step learning problem: anatomical structure localization and boundary delineation. In both steps, we exploit the recent advances in learning discriminative models. A novel algorithm, marginal space learning (MSL), is introduced to solve the 9-D similarity transformation search problem for localizing the heart chambers. After determining the pose of the heart chambers, we estimate the 3-D shape through learning-based boundary delineation. The proposed method has been extensively tested on the largest dataset (with 323 volumes from 137 patients) ever reported in the literature. To the best of our knowledge, our system is the fastest with a speed of 4.0 s per volume (on a dual-core 3.2-GHz processor) for the automatic segmentation of all four chambers.

  5. Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume.

    PubMed

    van Horssen, P; van Lier, M G J T B; van den Wijngaard, J P H M; VanBavel, E; Hoefer, I E; Spaan, J A E; Siebes, M

    2016-04-01

    Computational predictions of the functional stenosis severity from coronary imaging data use an allometric scaling law to derive hyperemic blood flow (Q) from coronary arterial volume (V), Q = αV(β) Reliable estimates of α and β are essential for meaningful flow estimations. We hypothesize that the relation between Q and V depends on imaging resolution. In five canine hearts, fluorescent microspheres were injected into the left anterior descending coronary artery during maximal hyperemia. The coronary arteries of the excised heart were filled with fluorescent cast material, frozen, and processed with an imaging cryomicrotome to yield a three-dimensional representation of the coronary arterial network. The effect of limited image resolution was simulated by assessing scaling law parameters from the virtual arterial network at 11 truncation levels ranging from 50 to 1,000 μm segment radius. Mapped microsphere locations were used to derive the corresponding relative Q using a reference truncation level of 200 μm. The scaling law factor α did not change with truncation level, despite considerable intersubject variability. In contrast, the scaling law exponent β decreased from 0.79 to 0.55 with increasing truncation radius and was significantly lower for truncation radii above 500 μm vs. 50 μm (P< 0.05). Hyperemic Q was underestimated for vessel truncation above the reference level. In conclusion, flow-crown volume relations confirmed overall power law behavior; however, this relation depends on the terminal vessel radius that can be visualized. The scaling law exponent β should therefore be adapted to the resolution of the imaging modality. PMID:26825519

  6. Influence of segmented vessel size due to limited imaging resolution on coronary hyperemic flow prediction from arterial crown volume.

    PubMed

    van Horssen, P; van Lier, M G J T B; van den Wijngaard, J P H M; VanBavel, E; Hoefer, I E; Spaan, J A E; Siebes, M

    2016-04-01

    Computational predictions of the functional stenosis severity from coronary imaging data use an allometric scaling law to derive hyperemic blood flow (Q) from coronary arterial volume (V), Q = αV(β) Reliable estimates of α and β are essential for meaningful flow estimations. We hypothesize that the relation between Q and V depends on imaging resolution. In five canine hearts, fluorescent microspheres were injected into the left anterior descending coronary artery during maximal hyperemia. The coronary arteries of the excised heart were filled with fluorescent cast material, frozen, and processed with an imaging cryomicrotome to yield a three-dimensional representation of the coronary arterial network. The effect of limited image resolution was simulated by assessing scaling law parameters from the virtual arterial network at 11 truncation levels ranging from 50 to 1,000 μm segment radius. Mapped microsphere locations were used to derive the corresponding relative Q using a reference truncation level of 200 μm. The scaling law factor α did not change with truncation level, despite considerable intersubject variability. In contrast, the scaling law exponent β decreased from 0.79 to 0.55 with increasing truncation radius and was significantly lower for truncation radii above 500 μm vs. 50 μm (P< 0.05). Hyperemic Q was underestimated for vessel truncation above the reference level. In conclusion, flow-crown volume relations confirmed overall power law behavior; however, this relation depends on the terminal vessel radius that can be visualized. The scaling law exponent β should therefore be adapted to the resolution of the imaging modality.

  7. Topology-corrected segmentation and local intensity estimates for improved partial volume classification of brain cortex in MRI.

    PubMed

    Rueda, Andrea; Acosta, Oscar; Couprie, Michel; Bourgeat, Pierrick; Fripp, Jurgen; Dowson, Nicholas; Romero, Eduardo; Salvado, Olivier

    2010-05-15

    In magnetic resonance imaging (MRI), accuracy and precision with which brain structures may be quantified are frequently affected by the partial volume (PV) effect. PV is due to the limited spatial resolution of MRI compared to the size of anatomical structures. Accurate classification of mixed voxels and correct estimation of the proportion of each pure tissue (fractional content) may help to increase the precision of cortical thickness estimation in regions where this measure is particularly difficult, such as deep sulci. The contribution of this work is twofold: on the one hand, we propose a new method to label voxels and compute tissue fractional content, integrating a mechanism for detecting sulci with topology preserving operators. On the other hand, we improve the computation of the fractional content of mixed voxels using local estimation of pure tissue intensity means. Accuracy and precision were assessed using simulated and real MR data and comparison with other existing approaches demonstrated the benefits of our method. Significant improvements in gray matter (GM) classification and cortical thickness estimation were brought by the topology correction. The fractional content root mean squared error diminished by 6.3% (p<0.01) on simulated data. The reproducibility error decreased by 8.8% (p<0.001) and the Jaccard similarity measure increased by 3.5% on real data. Furthermore, compared with manually guided expert segmentations, the similarity measure was improved by 12.0% (p<0.001). Thickness estimation with the proposed method showed a higher reproducibility compared with the measure performed after partial volume classification using other methods.

  8. SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

    SciTech Connect

    Soultan, D; Murphy, J; James, C; Hoh, C; Moiseenko, V; Cervino, L; Gill, B

    2015-06-15

    Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images were binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing.

  9. A new partial volume segmentation approach to extract bladder wall for computer-aided detection in virtual cystoscopy

    NASA Astrophysics Data System (ADS)

    Li, Lihong; Wang, Zigang; Li, Xiang; Wei, Xinzhou; Adler, Howard L.; Huang, Wei; Rizvi, Syed A.; Meng, Hong; Harrington, Donald P.; Liang, Zhengrong

    2004-04-01

    We propose a new partial volume (PV) segmentation scheme to extract bladder wall for computer aided detection (CAD) of bladder lesions using multispectral MR images. Compared with CT images, MR images provide not only a better tissue contrast between bladder wall and bladder lumen, but also the multispectral information. As multispectral images are spatially registered over three-dimensional space, information extracted from them is more valuable than that extracted from each image individually. Furthermore, the intrinsic T1 and T2 contrast of the urine against the bladder wall eliminates the invasive air insufflation procedure. Because the earliest stages of bladder lesion growth tend to develop gradually and migrate slowly from the mucosa into the bladder wall, our proposed PV algorithm quantifies images as percentages of tissues inside each voxel. It preserves both morphology and texture information and provides tissue growth tendency in addition to the anatomical structure. Our CAD system utilizes a multi-scan protocol on dual (full and empty of urine) states of the bladder to extract both geometrical and texture information. Moreover, multi-scan of transverse and coronal MR images eliminates motion artifacts. Experimental results indicate that the presented scheme is feasible towards mass screening and lesion detection for virtual cystoscopy (VC).

  10. Using Population Segmentation to Provide Better Health Care for All: The “Bridges to Health” Model

    PubMed Central

    Lynn, Joanne; Straube, Barry M; Bell, Karen M; Jencks, Stephen F; Kambic, Robert T

    2007-01-01

    The model discussed in this article divides the population into eight groups: people in good health, in maternal/infant situations, with an acute illness, with stable chronic conditions, with a serious but stable disability, with failing health near death, with advanced organ system failure, and with long-term frailty. Each group has its own definitions of optimal health and its own priorities among services. Interpreting these population-focused priorities in the context of the Institute of Medicine's six goals for quality yields a framework that could shape planning for resources, care arrangements, and service delivery, thus ensuring that each person's health needs can be met effectively and efficiently. Since this framework would guide each population segment across the institute's “Quality Chasm,” it is called the “Bridges to Health” model. PMID:17517112

  11. Relaxation of quantum state population and volume viscosity in He/H{sub 2} mixtures

    SciTech Connect

    Bruno, D.; Esposito, F.; Giovangigli, V.

    2014-12-09

    A kinetic model for He-H{sub 2} mixtures is studied in a regime where elastic collisions are fast and inelastic collisions are slow. Application of the Chapman-Enskog method yields a state to state fluid model where each quantum state is a separate pseudo species. The relaxation of quantum state population towards thermodynamic equilibrium is investigated as well as the definition of volume viscosity coefficients. The theoretical results are applied to the quantum state population and volume viscosity of molecular hydrogen on the basis of a complete set of cross sections for the He+H{sub 2}(v, j) system.

  12. Relaxation of quantum state population and volume viscosity in He / H2 mixtures

    NASA Astrophysics Data System (ADS)

    Bruno, D.; Esposito, F.; Giovangigli, V.

    2014-12-01

    A kinetic model for He - H2 mixtures is studied in a regime where elastic collisions are fast and inelastic collisions are slow. Application of the Chapman-Enskog method yields a state to state fluid model where each quantum state is a separate pseudo species. The relaxation of quantum state population towards thermodynamic equilibrium is investigated as well as the definition of volume viscosity coefficients. The theoretical results are applied to the quantum state population and volume viscosity of molecular hydrogen on the basis of a complete set of cross sections for the He + H2(v, j) system.

  13. HLA-F coding and regulatory segments variability determined by massively parallel sequencing procedures in a Brazilian population sample.

    PubMed

    Lima, Thálitta Hetamaro Ayala; Buttura, Renato Vidal; Donadi, Eduardo Antônio; Veiga-Castelli, Luciana Caricati; Mendes-Junior, Celso Teixeira; Castelli, Erick C

    2016-10-01

    Human Leucocyte Antigen F (HLA-F) is a non-classical HLA class I gene distinguished from its classical counterparts by low allelic polymorphism and distinctive expression patterns. Its exact function remains unknown. It is believed that HLA-F has tolerogenic and immune modulatory properties. Currently, there is little information regarding the HLA-F allelic variation among human populations and the available studies have evaluated only a fraction of the HLA-F gene segment and/or have searched for known alleles only. Here we present a strategy to evaluate the complete HLA-F variability including its 5' upstream, coding and 3' downstream segments by using massively parallel sequencing procedures. HLA-F variability was surveyed on 196 individuals from the Brazilian Southeast. The results indicate that the HLA-F gene is indeed conserved at the protein level, where thirty coding haplotypes or coding alleles were detected, encoding only four different HLA-F full-length protein molecules. Moreover, a same protein molecule is encoded by 82.45% of all coding alleles detected in this Brazilian population sample. However, the HLA-F nucleotide and haplotype variability is much higher than our current knowledge both in Brazilians and considering the 1000 Genomes Project data. This protein conservation is probably a consequence of the key role of HLA-F in the immune system physiology.

  14. Integration of Population Education in APPEAL. Volume Two: Population Education in Universal Primary Education.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization, Bangkok (Thailand). Principal Regional Office for Asia and the Pacific.

    These lesson plans are the result of two regional workshops sponsored by UNESCO in Indonesia in 1989 and Pakistan in 1991. The workshops focused on the need to introduce population education core messages in the Asia-Pacific Programme of Education for All (APPEAL). These prototypes of exemplar instructional materials for primary education,…

  15. Influence of volume expansion on NaC1 reabsorption in the diluting segments of the nephron: a study using clearance methods.

    PubMed

    Danovitch, G M; Bricker, N S

    1976-09-01

    Whether volume expansion influences NaC1 reabsorption by the diluting segment of the nephron remains a matter of controversy. In the present studies this question has been examined in normal unanesthetized dogs, undergoing maximal water diuresis. Free water clearance (CH2O/GFR) has been used as the index of NaC1 reabsorption in the diluting segment. Three expressions have been employed for "distal delivery" of NaC1: a) V/GFR, designated as the "volume term"; b) (CNa/GFR + CH2O/GFR), the "sodium term;" and c) (CC1/GFR + CH2O/GFR), the "chloride term". The validity of these terms is discussed. Three techniques were used to increase distal delivery: 1) the administration of acetazolamide to dogs in which extracellular fluid (ECF) volume was not expanded (grop 1); 2) "moderate" volume expansion (group 2); and 3) "marked" volume expansion (group 3). CH2O/GFR increased progressively with rising values for "distal delivery" regardless of which term was used to calculate the latter. With all three delivery terms, differences in distal NaC1 reabsorption emerged between the two volume-expanded groups, though only with the "chloride" term did substantial differences also emerge between the nonexpanded group 1 dogs and both volume-expanded groups. In group 1, values for CH2O/GFR increased in close to a linear fashion up to distal delivery values equal to 24% of the volume of glomerular filtrate. However, at high rates of distal delivery the rate of rise of CH2O/GFR was less in group 2 than in group 1 and the depression of values was even greater in group 3. Within the limits of the techniques used, the data suggest that volume expansion inhibits fractional NaC1 reabsorption in the diluting segment of the nephron in a dose-related fashion. The "chloride" term was found to be superior to the "volume" and "sodium" terms in revealing these changes.

  16. A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

    PubMed Central

    Nitzsche, Björn; Frey, Stephen; Collins, Louis D.; Seeger, Johannes; Lobsien, Donald; Dreyer, Antje; Kirsten, Holger; Stoffel, Michael H.; Fonov, Vladimir S.; Boltze, Johannes

    2015-01-01

    Standard stereotaxic reference systems play a key role in human brain studies. Stereotaxic coordinate systems have also been developed for experimental animals including non-human primates, dogs, and rodents. However, they are lacking for other species being relevant in experimental neuroscience including sheep. Here, we present a spatial, unbiased ovine brain template with tissue probability maps (TPM) that offer a detailed stereotaxic reference frame for anatomical features and localization of brain areas, thereby enabling inter-individual and cross-study comparability. Three-dimensional data sets from healthy adult Merino sheep (Ovis orientalis aries, 12 ewes and 26 neutered rams) were acquired on a 1.5 T Philips MRI using a T1w sequence. Data were averaged by linear and non-linear registration algorithms. Moreover, animals were subjected to detailed brain volume analysis including examinations with respect to body weight (BW), age, and sex. The created T1w brain template provides an appropriate population-averaged ovine brain anatomy in a spatial standard coordinate system. Additionally, TPM for gray (GM) and white (WM) matter as well as cerebrospinal fluid (CSF) classification enabled automatic prior-based tissue segmentation using statistical parametric mapping (SPM). Overall, a positive correlation of GM volume and BW explained about 15% of the variance of GM while a positive correlation between WM and age was found. Absolute tissue volume differences were not detected, indeed ewes showed significantly more GM per bodyweight as compared to neutered rams. The created framework including spatial brain template and TPM represent a useful tool for unbiased automatic image preprocessing and morphological characterization in sheep. Therefore, the reported results may serve as a starting point for further experimental and/or translational research aiming at in vivo analysis in this species. PMID:26089780

  17. 76 FR 9734 - Endangered and Threatened Species; Proposed Threatened Status for Distinct Population Segments of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-22

    ..., 2010 (75 FR 77476), we published a proposed rule to list the Beringia and Okhotsk Distinct Population... (February 8, 2011) was extended to March 25, 2011 (76 FR 6754; February 8, 2011). Public Hearings Joint... both the proposed rule for bearded seals and the proposed rule for ringed seals (75 FR 77476;...

  18. Study of tracking and data acquisition system for the 1990's. Volume 4: TDAS space segment architecture

    NASA Technical Reports Server (NTRS)

    Orr, R. S.

    1984-01-01

    Tracking and data acquisition system (TDAS) requirements, TDAS architectural goals, enhanced TDAS subsystems, constellation and networking options, TDAS spacecraft options, crosslink implementation, baseline TDAS space segment architecture, and treat model development/security analysis are addressed.

  19. Estimation of stature from the foot and its segments in a sub-adult female population of North India

    PubMed Central

    2011-01-01

    Background Establishing personal identity is one of the main concerns in forensic investigations. Estimation of stature forms a basic domain of the investigation process in unknown and co-mingled human remains in forensic anthropology case work. The objective of the present study was to set up standards for estimation of stature from the foot and its segments in a sub-adult female population. Methods The sample for the study constituted 149 young females from the Northern part of India. The participants were aged between 13 and 18 years. Besides stature, seven anthropometric measurements that included length of the foot from each toe (T1, T2, T3, T4, and T5 respectively), foot breadth at ball (BBAL) and foot breadth at heel (BHEL) were measured on both feet in each participant using standard methods and techniques. Results The results indicated that statistically significant differences (p < 0.05) between left and right feet occur in both the foot breadth measurements (BBAL and BHEL). Foot length measurements (T1 to T5 lengths) did not show any statistically significant bilateral asymmetry. The correlation between stature and all the foot measurements was found to be positive and statistically significant (p-value < 0.001). Linear regression models and multiple regression models were derived for estimation of stature from the measurements of the foot. The present study indicates that anthropometric measurements of foot and its segments are valuable in the estimation of stature. Foot length measurements estimate stature with greater accuracy when compared to foot breadth measurements. Conclusions The present study concluded that foot measurements have a strong relationship with stature in the sub-adult female population of North India. Hence, the stature of an individual can be successfully estimated from the foot and its segments using different regression models derived in the study. The regression models derived in the study may be applied successfully for the

  20. Computer-aided measurement of liver volumes in CT by means of geodesic active contour segmentation coupled with level-set algorithms

    SciTech Connect

    Suzuki, Kenji; Kohlbrenner, Ryan; Epstein, Mark L.; Obajuluwa, Ademola M.; Xu Jianwu; Hori, Masatoshi

    2010-05-15

    Purpose: Computerized liver extraction from hepatic CT images is challenging because the liver often abuts other organs of a similar density. The purpose of this study was to develop a computer-aided measurement of liver volumes in hepatic CT. Methods: The authors developed a computerized liver extraction scheme based on geodesic active contour segmentation coupled with level-set contour evolution. First, an anisotropic diffusion filter was applied to portal-venous-phase CT images for noise reduction while preserving the liver structure, followed by a scale-specific gradient magnitude filter to enhance the liver boundaries. Then, a nonlinear grayscale converter enhanced the contrast of the liver parenchyma. By using the liver-parenchyma-enhanced image as a speed function, a fast-marching level-set algorithm generated an initial contour that roughly estimated the liver shape. A geodesic active contour segmentation algorithm coupled with level-set contour evolution refined the initial contour to define the liver boundaries more precisely. The liver volume was then calculated using these refined boundaries. Hepatic CT scans of 15 prospective liver donors were obtained under a liver transplant protocol with a multidetector CT system. The liver volumes extracted by the computerized scheme were compared to those traced manually by a radiologist, used as ''gold standard.''Results: The mean liver volume obtained with our scheme was 1504 cc, whereas the mean gold standard manual volume was 1457 cc, resulting in a mean absolute difference of 105 cc (7.2%). The computer-estimated liver volumetrics agreed excellently with the gold-standard manual volumetrics (intraclass correlation coefficient was 0.95) with no statistically significant difference (F=0.77; p(F{<=}f)=0.32). The average accuracy, sensitivity, specificity, and percent volume error were 98.4%, 91.1%, 99.1%, and 7.2%, respectively. Computerized CT liver volumetry would require substantially less completion time

  1. A hierarchical integrated population model for greater sage-grouse (Centrocercus urophasianus) in the Bi-State Distinct Population Segment, California and Nevada

    USGS Publications Warehouse

    Coates, Peter S.; Halstead, Brian J.; Blomberg, Erik J.; Brussee, Brianne; Howe, Kristy B.; Wiechman, Lief; Tebbenkamp, Joel; Reese, Kerry P.; Gardner, Scott C.; Casazza, Michael L.

    2014-01-01

    Greater sage-grouse (Centrocercus urophasianus, hereafter referred to as “sage-grouse”) are endemic to sagebrush (Artemisia spp.) ecosystems throughout Western North America. Populations of sage-grouse have declined in distribution and abundance across the range of the species (Schroeder and others, 2004; Knick and Connelly, 2011), largely as a result of human disruption of sagebrush communities (Knick and Connelly, 2011). The Bi-State Distinct Population Segment (DPS) represents sage-grouse populations that are geographically isolated and genetically distinct (Benedict and others, 2003; Oyler-McCance and others, 2005) and that are present at the extreme southwestern distribution of the sage-grouse range (Schroeder and others, 2004), straddling the border of California and Nevada. Subpopulations of sage-grouse in the DPS may be at increased risk of extirpation because of a substantial loss of sagebrush habitat and lack of connectivity (Oyler-McCance and others, 2005). Sage-grouse in the Bi-State DPS represent small, localized breeding populations distributed across 18,325 km2. The U.S. Fish and Wildlife Service currently (2014) is evaluating the Bi-State DPS as threatened or endangered under the Endangered Species Act of 1973, independent of other sage-grouse populations. This DPS was designated as a higher priority for listing than sage-grouse in other parts of the species’ range (U.S. Department of the Interior, 2010). Range-wide population analyses for sage-grouse have included portions of the Bi-State DPS (Sage and Columbian Sharp-tailed Grouse Technical Committee 2008; Garton and others, 2011). Although these analyses are informative, the underlying data only represent a portion of the DPS and are comprised of lek count observations only. A thorough examination of population dynamics and persistence that includes multiple subpopulations and represents the majority of the DPS is largely lacking. Furthermore, fundamental information on population growth

  2. A multi-model approach to simultaneous segmentation and classification of heterogeneous populations of cell nuclei in 3D confocal microscope images.

    PubMed

    Lin, Gang; Chawla, Monica K; Olson, Kathy; Barnes, Carol A; Guzowski, John F; Bjornsson, Christopher; Shain, William; Roysam, Badrinath

    2007-09-01

    Automated segmentation and morphometry of fluorescently labeled cell nuclei in batches of 3D confocal stacks is essential for quantitative studies. Model-based segmentation algorithms are attractive due to their robustness. Previous methods incorporated a single nuclear model. This is a limitation for tissues containing multiple cell types with different nuclear features. Improved segmentation for such tissues requires algorithms that permit multiple models to be used simultaneously. This requires a tight integration of classification and segmentation algorithms. Two or more nuclear models are constructed semiautomatically from user-provided training examples. Starting with an initial over-segmentation produced by a gradient-weighted watershed algorithm, a hierarchical fragment merging tree rooted at each object is built. Linear discriminant analysis is used to classify each candidate using multiple object models. On the basis of the selected class, a Bayesian score is computed. Fragment merging decisions are made by comparing the score with that of other candidates, and the scores of constituent fragments of each candidate. The overall segmentation accuracy was 93.7% and classification accuracy was 93.5%, respectively, on a diverse collection of images drawn from five different regions of the rat brain. The multi-model method was found to achieve high accuracy on nuclear segmentation and classification by correctly resolving ambiguities in clustered regions containing heterogeneous cell populations.

  3. Evaluation of Lacrimal Gland Dimensions and Volume in Turkish Population with Computed Tomography

    PubMed Central

    Yazici, Alper; Yanik, Bahar; Yazici, Hasmet; Demirpolat, Gulen

    2016-01-01

    Introduction Computed tomography (CT) is a widespread method for evaluating head and neck pathologies. The lacrimal glands (LGs) are usually visible in routine head and neck CT scans. LG pathologies usually manifests with changes in gland sizes, so it is important to know the normal values of the LG dimensions and volume. The LG sizes may change with age, gender and race. The normal values of LG dimensions and volume in Turkish population was not reported before. Aim The aim of this study was to evaluate the dimensions and volumes of the LGs by CT in a Turkish population. Materials and Methods Two hundred seventeen consecutive paranasal CT scans of subjects evaluated retrospectively. Measurements of LG dimensions were performed in axial and coronal paranasal CT images. The LG volume was calculated with Aquarius software by outlining the gland in all consecutive axial images. Results Four hundred orbits of 200 subjects were included to the study. The mean axial LG length in right and left orbits were 16.2±2.0 mm and 16.0±2.0 mm and the mean axial width of the right and left orbits were 4.1±0.7 mm and 4.0±0.7 mm. The right and left LG mean values for coronal length and width were equal 18.3 ±2.2 mm and 4.1±0.7mm respectively. The mean LG volume was 0.617±0.210 cm3 in right and 0.597±0.197 cm3 in the left orbits. There were statistically significant differences in the axial width and volume of the LG according to sides, however there was no significant difference according to gender. Age and LG measurements were negatively correlated. Conclusion Our study may serve as a guide to determine the average values of the LG measurements in Turkish population and find out the orbital pathologies that involves the LG. PMID:27042554

  4. [Effects of population density and culture volume on the growth and reproduction of Moina irrasa].

    PubMed

    Chen, Li-Na; Li, Yu-Ying; Deng, Dao-Gui; Jin, Xian-Wen; Ge, Qian; Wang, Shao-Qin

    2012-07-01

    A laboratory experiment was conducted to study the effects of different population density (D1 : 100 ind x L(-1), D2 : 150 ind x L(-1), D3 : 300 ind x L(-1)) and culture volume (V1: 50 mL, V2 : 100 mL, V3 : 400 mL) on the growth and reproduction of Moina irrasa at 25 degrees C. At the same culture density, the body length of the M. irrasa females at their first pregnancy, the first brood, and the total offsprings per female decreased with the increase of culture volumes, while the sex ratio (male/female) of the offsprings was in adverse. At the same culture volumes, the total offsprings per female decreased with the increase of culture density. At D1 V1, the body length of the females at their first pregnancy (0.95 +/- 0.10 mm) and the total offsprings (171.3 +/- 19.8 ind) per female were the maximum. At D3V2, the sex ratio was the maximum (0.54 +/- 0.05). Culture density, culture volume, and their interactions significantly affected the total offsprings per female and the sex ratio (P < 0.001). PMID:23173474

  5. [Effects of population density and culture volume on the growth and reproduction of Moina irrasa].

    PubMed

    Chen, Li-Na; Li, Yu-Ying; Deng, Dao-Gui; Jin, Xian-Wen; Ge, Qian; Wang, Shao-Qin

    2012-07-01

    A laboratory experiment was conducted to study the effects of different population density (D1 : 100 ind x L(-1), D2 : 150 ind x L(-1), D3 : 300 ind x L(-1)) and culture volume (V1: 50 mL, V2 : 100 mL, V3 : 400 mL) on the growth and reproduction of Moina irrasa at 25 degrees C. At the same culture density, the body length of the M. irrasa females at their first pregnancy, the first brood, and the total offsprings per female decreased with the increase of culture volumes, while the sex ratio (male/female) of the offsprings was in adverse. At the same culture volumes, the total offsprings per female decreased with the increase of culture density. At D1 V1, the body length of the females at their first pregnancy (0.95 +/- 0.10 mm) and the total offsprings (171.3 +/- 19.8 ind) per female were the maximum. At D3V2, the sex ratio was the maximum (0.54 +/- 0.05). Culture density, culture volume, and their interactions significantly affected the total offsprings per female and the sex ratio (P < 0.001).

  6. Effect of radical prostatectomy surgeon volume on complication rates from a large population-based cohort

    PubMed Central

    Almatar, Ashraf; Wallis, Christopher J.D.; Herschorn, Sender; Saskin, Refik; Kulkarni, Girish S.; Kodama, Ronald T.; Nam, Robert K.

    2016-01-01

    Introduction: Surgical volume can affect several outcomes following radical prostatectomy (RP). We examined if surgical volume was associated with novel categories of treatment-related complications following RP. Methods: We examined a population-based cohort of men treated with RP in Ontario, Canada between 2002 and 2009. We used Cox proportional hazard modeling to examine the effect of physician, hospital and patient demographic factors on rates of treatment-related hospital admissions, urologic procedures, and open surgeries. Results: Over the study interval, 15 870 men were treated with RP. A total of 196 surgeons performed a median of 15 cases per year (range: 1–131). Patients treated by surgeons in the highest quartile of annual case volume (>39/year) had a lower risk of hospital admission (hazard ratio [HR]=0.54, 95% CI 0.47–0.61) and urologic procedures (HR=0.69, 95% CI 0.64–0.75), but not open surgeries (HR=0.83, 95% CI 0.47–1.45) than patients treated by surgeons in the lowest quartile (<15/year). Treatment at an academic hospital was associated with a decreased risk of hospitalization (HR=0.75, 95% CI 0.67–0.83), but not of urologic procedures (HR=0.94, 95% CI 0.88–1.01) or open surgeries (HR=0.87, 95% CI 0.54–1.39). There was no significant trend in any of the outcomes by population density. Conclusions: The annual case volume of the treating surgeon significantly affects a patient’s risk of requiring hospitalization or urologic procedures (excluding open surgeries) to manage treatment-related complications. PMID:26977206

  7. Diurnal fluctuations in brain volume: Statistical analyses of MRI from large populations.

    PubMed

    Nakamura, Kunio; Brown, Robert A; Narayanan, Sridar; Collins, D Louis; Arnold, Douglas L

    2015-09-01

    We investigated fluctuations in brain volume throughout the day using statistical modeling of magnetic resonance imaging (MRI) from large populations. We applied fully automated image analysis software to measure the brain parenchymal fraction (BPF), defined as the ratio of the brain parenchymal volume and intracranial volume, thus accounting for variations in head size. The MRI data came from serial scans of multiple sclerosis (MS) patients in clinical trials (n=755, 3269 scans) and from subjects participating in the Alzheimer's Disease Neuroimaging Initiative (ADNI, n=834, 6114 scans). The percent change in BPF was modeled with a linear mixed effect (LME) model, and the model was applied separately to the MS and ADNI datasets. The LME model for the MS datasets included random subject effects (intercept and slope over time) and fixed effects for the time-of-day, time from the baseline scan, and trial, which accounted for trial-related effects (for example, different inclusion criteria and imaging protocol). The model for ADNI additionally included the demographics (baseline age, sex, subject type [normal, mild cognitive impairment, or Alzheimer's disease], and interaction between subject type and time from baseline). There was a statistically significant effect of time-of-day on the BPF change in MS clinical trial datasets (-0.180 per day, that is, 0.180% of intracranial volume, p=0.019) as well as the ADNI dataset (-0.438 per day, that is, 0.438% of intracranial volume, p<0.0001), showing that the brain volume is greater in the morning. Linearly correcting the BPF values with the time-of-day reduced the required sample size to detect a 25% treatment effect (80% power and 0.05 significance level) on change in brain volume from 2 time-points over a period of 1year by 2.6%. Our results have significant implications for future brain volumetric studies, suggesting that there is a potential acquisition time bias that should be randomized or statistically controlled to

  8. A fully automatic, threshold-based segmentation method for the estimation of the Metabolic Tumor Volume from PET images: validation on 3D printed anthropomorphic oncological lesions

    NASA Astrophysics Data System (ADS)

    Gallivanone, F.; Interlenghi, M.; Canervari, C.; Castiglioni, I.

    2016-01-01

    18F-Fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) is a standard functional diagnostic technique to in vivo image cancer. Different quantitative paramters can be extracted from PET images and used as in vivo cancer biomarkers. Between PET biomarkers Metabolic Tumor Volume (MTV) has gained an important role in particular considering the development of patient-personalized radiotherapy treatment for non-homogeneous dose delivery. Different imaging processing methods have been developed to define MTV. The different proposed PET segmentation strategies were validated in ideal condition (e.g. in spherical objects with uniform radioactivity concentration), while the majority of cancer lesions doesn't fulfill these requirements. In this context, this work has a twofold objective: 1) to implement and optimize a fully automatic, threshold-based segmentation method for the estimation of MTV, feasible in clinical practice 2) to develop a strategy to obtain anthropomorphic phantoms, including non-spherical and non-uniform objects, miming realistic oncological patient conditions. The developed PET segmentation algorithm combines an automatic threshold-based algorithm for the definition of MTV and a k-means clustering algorithm for the estimation of the background. The method is based on parameters always available in clinical studies and was calibrated using NEMA IQ Phantom. Validation of the method was performed both in ideal (e.g. in spherical objects with uniform radioactivity concentration) and non-ideal (e.g. in non-spherical objects with a non-uniform radioactivity concentration) conditions. The strategy to obtain a phantom with synthetic realistic lesions (e.g. with irregular shape and a non-homogeneous uptake) consisted into the combined use of standard anthropomorphic phantoms commercially and irregular molds generated using 3D printer technology and filled with a radioactive chromatic alginate. The proposed segmentation algorithm was feasible in a

  9. Structural Alterations of Segmented Macular Inner Layers in Aquaporin4-Antibody-Positive Optic Neuritis Patients in a Chinese Population

    PubMed Central

    Peng, Chunxia; Wang, Wei; Xu, Quangang; Zhao, Shuo; Li, Hongyang; Yang, Mo; Cao, Shanshan; Zhou, Huanfen; Wei, Shihui

    2016-01-01

    Objectives This study aimed to analyse the structural injury of the peripapillary retinal nerve fibre layer (pRNFL) and segmented macular layers in optic neuritis (ON) in aquaporin4-antibody (AQP4-Ab) seropositivity(AQP4-Ab-positiveON) patients and in AQP4-Ab seronegativity (AQP4-Ab-negative ON) patients in order to evaluate their correlations with the best-corrected visual acuity (BCVA) and the value of the early diagnosis of neuromyelitis optica (NMO). Design This is a retrospective, cross-sectional and control observational study. Methods In total, 213 ON patients (291 eyes) and 50 healthy controls (HC) (100 eyes) were recruited in this study. According to a serum AQP4-Ab assay, 98 ON patients (132 eyes) were grouped as AQP4-Ab-positive ON and 115 ON patients (159 eyes) were grouped as AQP4-Ab-negative ON cohorts. All subjects underwent scanning with spectralis optical coherence tomography (OCT) and BCVA tests. pRNFL and segmented macular layer measurements were analysed. Results The pRNFL thickness in AQP4-Ab-positive ON eyes showed a more serious loss during 0–2 months (-27.61μm versus -14.47 μm) and ≥6 months (-57.91μm versus -47.19μm) when compared with AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON preferentially damaged the nasal lateral pRNFL. The alterations in the macular ganglion cell layer plus the inner plexiform layer (GCIP) in AQP4-Ab-positive ON eyes were similar to those in AQP4-Ab-negative ON eyes. AQP4-Ab-positive ON eyes had entirely different injury patterns in the inner nuclear layer (INL) compared with AQP4-Ab-negative ON eyes during the first 6 months after the initial ON attack. These differences were as follows: the INL volume of AQP4-Ab-positive ON eyes had a gradual growing trend compared with AQP4-Ab-negative ON eyes, and it increased rapidly during 0–2 months, reached its peak during 2–4 months, and then decreased gradually. The pRNFL and GCIP in AQP4-Ab-positive ON eyes had positive correlations with BCVA. When the p

  10. A Comparison of Amplitude-Based and Phase-Based Positron Emission Tomography Gating Algorithms for Segmentation of Internal Target Volumes of Tumors Subject to Respiratory Motion

    SciTech Connect

    Jani, Shyam S.; Robinson, Clifford G.; Dahlbom, Magnus; White, Benjamin M.; Thomas, David H.; Gaudio, Sergio; Low, Daniel A.; Lamb, James M.

    2013-11-01

    Purpose: To quantitatively compare the accuracy of tumor volume segmentation in amplitude-based and phase-based respiratory gating algorithms in respiratory-correlated positron emission tomography (PET). Methods and Materials: List-mode fluorodeoxyglucose-PET data was acquired for 10 patients with a total of 12 fluorodeoxyglucose-avid tumors and 9 lymph nodes. Additionally, a phantom experiment was performed in which 4 plastic butyrate spheres with inner diameters ranging from 1 to 4 cm were imaged as they underwent 1-dimensional motion based on 2 measured patient breathing trajectories. PET list-mode data were gated into 8 bins using 2 amplitude-based (equal amplitude bins [A1] and equal counts per bin [A2]) and 2 temporal phase-based gating algorithms. Gated images were segmented using a commercially available gradient-based technique and a fixed 40% threshold of maximum uptake. Internal target volumes (ITVs) were generated by taking the union of all 8 contours per gated image. Segmented phantom ITVs were compared with their respective ground-truth ITVs, defined as the volume subtended by the tumor model positions covering 99% of breathing amplitude. Superior-inferior distances between sphere centroids in the end-inhale and end-exhale phases were also calculated. Results: Tumor ITVs from amplitude-based methods were significantly larger than those from temporal-based techniques (P=.002). For lymph nodes, A2 resulted in ITVs that were significantly larger than either of the temporal-based techniques (P<.0323). A1 produced the largest and most accurate ITVs for spheres with diameters of ≥2 cm (P=.002). No significant difference was shown between algorithms in the 1-cm sphere data set. For phantom spheres, amplitude-based methods recovered an average of 9.5% more motion displacement than temporal-based methods under regular breathing conditions and an average of 45.7% more in the presence of baseline drift (P<.001). Conclusions: Target volumes in images generated

  11. The influence of prostate volume on cancer detection in the Chinese population.

    PubMed

    Wu, Yi-Shuo; Na, Rong; Xu, Jian-Feng; Bai, Pei-De; Jiang, Hao-Wen; Ding, Qiang

    2014-01-01

    In western populations, prostate volume (PV) has been proven to be one of the strongest predictors of detecting prostate cancer (PCa) in biopsies. We performed this study in a biopsy cohort, to evaluate associations among the prostate volume, prostate-specific antigen (PSA) and PCa detection in the Chinese population. Between the years, 2007-13, 1486 men underwent prostate biopsy at Huashan Hospital, Fudan University, Shanghai, China. The study population was divided into two groups for analysis according to total PSA (tPSA) range (4 ng ml-1 < tPSA ≤ 20 ng ml-1 and tPSA > 20 ng ml-1 ). PV, age, tPSA, digital rectal examination (DRE) and transrectal ultrasound (TRUS) results were also included in the analysis. Although the positive biopsy rates decreased in both tPSA range groups, the downtrend was more pronounced in the 4 ng ml-1 < tPSA ≤ 20 ng ml-1 group; therefore, we focused on 853 men in this group with increasing PV. In multivariate logistic regression analysis, only DRE was found to be associated with PCa in four PV groups (P < 0.05) and tPSA did not show a good predictive ability when PV exceeded 50 ml (P > 0.05). Further, it may suggest that with increasing PV, the cancer detection rate decreased in men with different tPSA, DRE and TRUS nodule statuses (all P values for trends were <0.001). Our study indicates that in tPSA ranging from 4 to 20 ng ml-1 , the use of PV ranges of 0-35 ml, 35-50 ml and > 50 ml might be taken into consideration for the biopsy decision-making in the Chinese population.

  12. CT-based manual segmentation and evaluation of paranasal sinuses.

    PubMed

    Pirner, S; Tingelhoff, K; Wagner, I; Westphal, R; Rilk, M; Wahl, F M; Bootz, F; Eichhorn, Klaus W G

    2009-04-01

    Manual segmentation of computed tomography (CT) datasets was performed for robot-assisted endoscope movement during functional endoscopic sinus surgery (FESS). Segmented 3D models are needed for the robots' workspace definition. A total of 50 preselected CT datasets were each segmented in 150-200 coronal slices with 24 landmarks being set. Three different colors for segmentation represent diverse risk areas. Extension and volumetric measurements were performed. Three-dimensional reconstruction was generated after segmentation. Manual segmentation took 8-10 h for each CT dataset. The mean volumes were: right maxillary sinus 17.4 cm(3), left side 17.9 cm(3), right frontal sinus 4.2 cm(3), left side 4.0 cm(3), total frontal sinuses 7.9 cm(3), sphenoid sinus right side 5.3 cm(3), left side 5.5 cm(3), total sphenoid sinus volume 11.2 cm(3). Our manually segmented 3D-models present the patient's individual anatomy with a special focus on structures in danger according to the diverse colored risk areas. For safe robot assistance, the high-accuracy models represent an average of the population for anatomical variations, extension and volumetric measurements. They can be used as a database for automatic model-based segmentation. None of the segmentation methods so far described provide risk segmentation. The robot's maximum distance to the segmented border can be adjusted according to the differently colored areas.

  13. Development of an automated 3D segmentation program for volume quantification of body fat distribution using CT.

    PubMed

    Ohshima, Shunsuke; Yamamoto, Shuji; Yamaji, Taiki; Suzuki, Masahiro; Mutoh, Michihiro; Iwasaki, Motoki; Sasazuki, Shizuka; Kotera, Ken; Tsugane, Shoichiro; Muramatsu, Yukio; Moriyama, Noriyuki

    2008-09-20

    The objective of this study was to develop a computing tool for full-automatic segmentation of body fat distributions on volumetric CT images. We developed an algorithm to automatically identify the body perimeter and the inner contour that separates visceral fat from subcutaneous fat. Diaphragmatic surfaces can be extracted by model-based segmentation to match the bottom surface of the lung in CT images for determination of the upper limitation of the abdomen. The functions for quantitative evaluation of abdominal obesity or obesity-related metabolic syndrome were implemented with a prototype three-dimensional (3D) image processing workstation. The volumetric ratios of visceral fat to total fat and visceral fat to subcutaneous fat for each subject can be calculated. Additionally, color intensity mapping of subcutaneous areas and the visceral fat layer is quite obvious in understanding the risk of abdominal obesity with the 3D surface display. Preliminary results obtained have been useful in medical checkups and have contributed to improved efficiency in checking obesity throughout the whole range of the abdomen with 3D visualization and analysis.

  14. Viable tumor volume: volume of interest within segmented metastatic lesions, a pilot study of proposed computed tomography response criteria for urothelial cancer

    PubMed Central

    Folio, Les Roger; Turkbey, Evrim B.; Steinberg, Seth M.; Apolo, Andrea B.

    2015-01-01

    Objectives To evaluate the ability of new computed tomography (CT) response criteria for solid tumors such as urothelial cancer (VTV; viable tumor volume) to predict overall survival (OS) in patients with metastatic bladder cancer treated with cabozantinib. Materials and Methods We compared the relative capabilities of VTV, RECIST, MASS (morphology, attenuation, size, and structure), and Choi criteria, as well as volume measurements, to predict OS using serial follow-up contrast-enhanced CT exams in patients with metastatic urothelial carcinoma. Kaplan-Meier curves and 2-tailed log-rank tests compared OS based on early RECIST 1.1 response against each of the other criteria. A Cox proportional hazards model assessed response at follow-up exams as a time-varying covariate for OS. Results We assessed 141 lesions in 55 CT scans from 17 patients with urothelial metastasis, comparing VTV, RECIST, MASS, and Choi criteria, and volumetric measurements, for response assessment. Median follow-up was 4.5 months, range was 2–14 months. Only the VTV criteria demonstrated a statistical association with OS (p = 0.019; median OS 9.7 vs. 3.5 months). Conclusion This pilot study suggests that VTV is a promising tool for assessing tumor response and predicting OS, using criteria that incorporate tumor volume and density in patients receiving antiangiogenic therapy for urothelial cancer. Larger studies are warranted to validate these findings. PMID:26149529

  15. Respiratory muscle force and lung volume changes in a population of children with sickle cell disease.

    PubMed

    Ong, Bruce A; Caboot, Jason; Jawad, Abbas; McDonough, Joseph; Jackson, Tannoa; Arens, Raanan; Marcus, Carole L; Smith-Whitley, Kim; Mason, Thornton B A; Ohene-Frempong, Kwaku; Allen, Julian L

    2013-10-01

    Sickle cell disease (SCD) is a disorder known to impact the respiratory system. We sought to identify respiratory muscle force and lung volume relationships in a paediatric SCD population. Thirty-four SCD-SS subjects underwent pulmonary function testing. Height, weight, age, and gender-adjusted percent predicted maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) values were compared to spirometry and lung volumes. Statistical analyses were performed using Pearson's correlation coefficient and paired two-tailed t-test. The mean ± standard deviation (SD) MIP and MEP was 69·6 ± 31·6 cm H2 O and 66·9 ± 22·9 cm H2 O, respectively, and mean ± SD percent predicted MIP (101·3 ± 45·9) exceeded MEP (72·1 ± 26·0) (P = 0·002). MIP correlated with forced vital capacity (FVC; r = 0·51, P = 0·001) and TLC (r = 0·54, P < 0·0001). MEP also correlated with FVC (r = 0·43, P = 0·011) and total lung capacity (TLC; r = 0·42, P = 0·013). Pearson's correlation coefficient testing yielded relationships between MIP and MEP (r = 0·64, P < 0·0001). SCD-SS patients showed correlations between respiratory muscle force and lung volume, and reduced percent predicted expiratory muscle force compared to inspiratory muscle force. Respiratory muscle strength may affect lung volumes in these patients, and expiratory muscles may be more susceptible than the diaphragm to SCD-induced vaso-occlusive damage.

  16. Semi-automatic segmentation and modeling of the cervical spinal cord for volume quantification in multiple sclerosis patients from magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Sonkova, Pavlina; Evangelou, Iordanis E.; Gallo, Antonio; Cantor, Fredric K.; Ohayon, Joan; McFarland, Henry F.; Bagnato, Francesca

    2008-03-01

    Spinal cord (SC) tissue loss is known to occur in some patients with multiple sclerosis (MS), resulting in SC atrophy. Currently, no measurement tools exist to determine the magnitude of SC atrophy from Magnetic Resonance Images (MRI). We have developed and implemented a novel semi-automatic method for quantifying the cervical SC volume (CSCV) from Magnetic Resonance Images (MRI) based on level sets. The image dataset consisted of SC MRI exams obtained at 1.5 Tesla from 12 MS patients (10 relapsing-remitting and 2 secondary progressive) and 12 age- and gender-matched healthy volunteers (HVs). 3D high resolution image data were acquired using an IR-FSPGR sequence acquired in the sagittal plane. The mid-sagittal slice (MSS) was automatically located based on the entropy calculation for each of the consecutive sagittal slices. The image data were then pre-processed by 3D anisotropic diffusion filtering for noise reduction and edge enhancement before segmentation with a level set formulation which did not require re-initialization. The developed method was tested against manual segmentation (considered ground truth) and intra-observer and inter-observer variability were evaluated.

  17. Integration of 3D scale-based pseudo-enhancement correction and partial volume image segmentation for improving electronic colon cleansing in CT colonograpy.

    PubMed

    Zhang, Hao; Li, Lihong; Zhu, Hongbin; Han, Hao; Song, Bowen; Liang, Zhengrong

    2014-01-01

    Orally administered tagging agents are usually used in CT colonography (CTC) to differentiate residual bowel content from native colonic structures. However, the high-density contrast agents tend to introduce pseudo-enhancement (PE) effect on neighboring soft tissues and elevate their observed CT attenuation value toward that of the tagged materials (TMs), which may result in an excessive electronic colon cleansing (ECC) since the pseudo-enhanced soft tissues are incorrectly identified as TMs. To address this issue, we integrated a 3D scale-based PE correction into our previous ECC pipeline based on the maximum a posteriori expectation-maximization partial volume (PV) segmentation. The newly proposed ECC scheme takes into account both the PE and PV effects that commonly appear in CTC images. We evaluated the new scheme on 40 patient CTC scans, both qualitatively through display of segmentation results, and quantitatively through radiologists' blind scoring (human observer) and computer-aided detection (CAD) of colon polyps (computer observer). Performance of the presented algorithm has shown consistent improvements over our previous ECC pipeline, especially for the detection of small polyps submerged in the contrast agents. The CAD results of polyp detection showed that 4 more submerged polyps were detected for our new ECC scheme over the previous one.

  18. Incorporation of texture-based features in optimal graph-theoretic approach with application to the 3D segmentation of intraretinal surfaces in SD-OCT volumes

    NASA Astrophysics Data System (ADS)

    Antony, Bhavna J.; Abràmoff, Michael D.; Sonka, Milan; Kwon, Young H.; Garvin, Mona K.

    2012-02-01

    While efficient graph-theoretic approaches exist for the optimal (with respect to a cost function) and simultaneous segmentation of multiple surfaces within volumetric medical images, the appropriate design of cost functions remains an important challenge. Previously proposed methods have used simple cost functions or optimized a combination of the same, but little has been done to design cost functions using learned features from a training set, in a less biased fashion. Here, we present a method to design cost functions for the simultaneous segmentation of multiple surfaces using the graph-theoretic approach. Classified texture features were used to create probability maps, which were incorporated into the graph-search approach. The efficiency of such an approach was tested on 10 optic nerve head centered optical coherence tomography (OCT) volumes obtained from 10 subjects that presented with glaucoma. The mean unsigned border position error was computed with respect to the average of manual tracings from two independent observers and compared to our previously reported results. A significant improvement was noted in the overall means which reduced from 9.25 +/- 4.03μm to 6.73 +/- 2.45μm (p < 0.01) and is also comparable with the inter-observer variability of 8.85 +/- 3.85μm.

  19. Using semi-automated segmentation of computed tomography datasets for three-dimensional visualization and volume measurements of equine paranasal sinuses.

    PubMed

    Brinkschulte, Markus; Bienert-Zeit, Astrid; Lüpke, Matthias; Hellige, Maren; Staszyk, Carsten; Ohnesorge, Bernhard

    2013-01-01

    The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region. PMID:23890087

  20. Fast segmentation and high-quality three-dimensional volume mesh creation from medical images for diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Jermyn, Michael; Ghadyani, Hamid; Mastanduno, Michael A.; Turner, Wes; Davis, Scott C.; Dehghani, Hamid; Pogue, Brian W.

    2013-08-01

    Multimodal approaches that combine near-infrared (NIR) and conventional imaging modalities have been shown to improve optical parameter estimation dramatically and thus represent a prevailing trend in NIR imaging. These approaches typically involve applying anatomical templates from magnetic resonance imaging/computed tomography/ultrasound images to guide the recovery of optical parameters. However, merging these data sets using current technology requires multiple software packages, substantial expertise, significant time-commitment, and often results in unacceptably poor mesh quality for optical image reconstruction, a reality that represents a significant roadblock for translational research of multimodal NIR imaging. This work addresses these challenges directly by introducing automated digital imaging and communications in medicine image stack segmentation and a new one-click three-dimensional mesh generator optimized for multimodal NIR imaging, and combining these capabilities into a single software package (available for free download) with a streamlined workflow. Image processing time and mesh quality benchmarks were examined for four common multimodal NIR use-cases (breast, brain, pancreas, and small animal) and were compared to a commercial image processing package. Applying these tools resulted in a fivefold decrease in image processing time and 62% improvement in minimum mesh quality, in the absence of extra mesh postprocessing. These capabilities represent a significant step toward enabling translational multimodal NIR research for both expert and nonexpert users in an open-source platform.

  1. Enrichment of diluted cell populations from large sample volumes using 3D carbon-electrode dielectrophoresis.

    PubMed

    Islam, Monsur; Natu, Rucha; Larraga-Martinez, Maria Fernanda; Martinez-Duarte, Rodrigo

    2016-05-01

    Here, we report on an enrichment protocol using carbon electrode dielectrophoresis to isolate and purify a targeted cell population from sample volumes up to 4 ml. We aim at trapping, washing, and recovering an enriched cell fraction that will facilitate downstream analysis. We used an increasingly diluted sample of yeast, 10(6)-10(2) cells/ml, to demonstrate the isolation and enrichment of few cells at increasing flow rates. A maximum average enrichment of 154.2 ± 23.7 times was achieved when the sample flow rate was 10 μl/min and yeast cells were suspended in low electrically conductive media that maximizes dielectrophoresis trapping. A COMSOL Multiphysics model allowed for the comparison between experimental and simulation results. Discussion is conducted on the discrepancies between such results and how the model can be further improved. PMID:27375816

  2. Enrichment of diluted cell populations from large sample volumes using 3D carbon-electrode dielectrophoresis.

    PubMed

    Islam, Monsur; Natu, Rucha; Larraga-Martinez, Maria Fernanda; Martinez-Duarte, Rodrigo

    2016-05-01

    Here, we report on an enrichment protocol using carbon electrode dielectrophoresis to isolate and purify a targeted cell population from sample volumes up to 4 ml. We aim at trapping, washing, and recovering an enriched cell fraction that will facilitate downstream analysis. We used an increasingly diluted sample of yeast, 10(6)-10(2) cells/ml, to demonstrate the isolation and enrichment of few cells at increasing flow rates. A maximum average enrichment of 154.2 ± 23.7 times was achieved when the sample flow rate was 10 μl/min and yeast cells were suspended in low electrically conductive media that maximizes dielectrophoresis trapping. A COMSOL Multiphysics model allowed for the comparison between experimental and simulation results. Discussion is conducted on the discrepancies between such results and how the model can be further improved.

  3. Automatic, accurate, and reproducible segmentation of the brain and cerebro-spinal fluid in T1-weighted volume MRI scans and its application to serial cerebral and intracranial volumetry

    NASA Astrophysics Data System (ADS)

    Lemieux, Louis

    2001-07-01

    A new fully automatic algorithm for the segmentation of the brain and cerebro-spinal fluid (CSF) from T1-weighted volume MRI scans of the head was specifically developed in the context of serial intra-cranial volumetry. The method is an extension of a previously published brain extraction algorithm. The brain mask is used as a basis for CSF segmentation based on morphological operations, automatic histogram analysis and thresholding. Brain segmentation is then obtained by iterative tracking of the brain-CSF interface. Grey matter (GM), white matter (WM) and CSF volumes are calculated based on a model of intensity probability distribution that includes partial volume effects. Accuracy was assessed using a digital phantom scan. Reproducibility was assessed by segmenting pairs of scans from 20 normal subjects scanned 8 months apart and 11 patients with epilepsy scanned 3.5 years apart. Segmentation accuracy as measured by overlap was 98% for the brain and 96% for the intra-cranial tissues. The volume errors were: total brain (TBV): -1.0%, intra-cranial (ICV):0.1%, CSF: +4.8%. For repeated scans, matching resulted in improved reproducibility. In the controls, the coefficient of reliability (CR) was 1.5% for the TVB and 1.0% for the ICV. In the patients, the Cr for the ICV was 1.2%.

  4. Automated Segmentability Index for Layer Segmentation of Macular SD-OCT Images

    PubMed Central

    Lee, Kyungmoo; Buitendijk, Gabriëlle H.S.; Bogunovic, Hrvoje; Springelkamp, Henriët; Hofman, Albert; Wahle, Andreas; Sonka, Milan; Vingerling, Johannes R.; Klaver, Caroline C.W.; Abràmoff, Michael D.

    2016-01-01

    Purpose To automatically identify which spectral-domain optical coherence tomography (SD-OCT) scans will provide reliable automated layer segmentations for more accurate layer thickness analyses in population studies. Methods Six hundred ninety macular SD-OCT image volumes (6.0 × 6.0 × 2.3 mm3) were obtained from one eyes of 690 subjects (74.6 ± 9.7 [mean ± SD] years, 37.8% of males) randomly selected from the population-based Rotterdam Study. The dataset consisted of 420 OCT volumes with successful automated retinal nerve fiber layer (RNFL) segmentations obtained from our previously reported graph-based segmentation method and 270 volumes with failed segmentations. To evaluate the reliability of the layer segmentations, we have developed a new metric, segmentability index SI, which is obtained from a random forest regressor based on 12 features using OCT voxel intensities, edge-based costs, and on-surface costs. The SI was compared with well-known quality indices, quality index (QI), and maximum tissue contrast index (mTCI), using receiver operating characteristic (ROC) analysis. Results The 95% confidence interval (CI) and the area under the curve (AUC) for the QI are 0.621 to 0.805 with AUC 0.713, for the mTCI 0.673 to 0.838 with AUC 0.756, and for the SI 0.784 to 0.920 with AUC 0.852. The SI AUC is significantly larger than either the QI or mTCI AUC (P < 0.01). Conclusions The segmentability index SI is well suited to identify SD-OCT scans for which successful automated intraretinal layer segmentations can be expected. Translational Relevance Interpreting the quantification of SD-OCT images requires the underlying segmentation to be reliable, but standard SD-OCT quality metrics do not predict which segmentations are reliable and which are not. The segmentability index SI presented in this study does allow reliable segmentations to be identified, which is important for more accurate layer thickness analyses in research and population studies. PMID:27066311

  5. Combining multi-atlas segmentation with brain surface estimation

    NASA Astrophysics Data System (ADS)

    Huo, Yuankai; Carass, Aaron; Resnick, Susan M.; Pham, Dzung L.; Prince, Jerry L.; Landman, Bennett A.

    2016-03-01

    Whole brain segmentation (with comprehensive cortical and subcortical labels) and cortical surface reconstruction are two essential techniques for investigating the human brain. The two tasks are typically conducted independently, however, which leads to spatial inconsistencies and hinders further integrated cortical analyses. To obtain self-consistent whole brain segmentations and surfaces, FreeSurfer segregates the subcortical and cortical segmentations before and after the cortical surface reconstruction. However, this "segmentation to surface to parcellation" strategy has shown limitation in various situations. In this work, we propose a novel "multi-atlas segmentation to surface" method called Multi-atlas CRUISE (MaCRUISE), which achieves self-consistent whole brain segmentations and cortical surfaces by combining multi-atlas segmentation with the cortical reconstruction method CRUISE. To our knowledge, this is the first work that achieves the reliability of state-of-the-art multi-atlas segmentation and labeling methods together with accurate and consistent cortical surface reconstruction. Compared with previous methods, MaCRUISE has three features: (1) MaCRUISE obtains 132 cortical/subcortical labels simultaneously from a single multi-atlas segmentation before reconstructing volume consistent surfaces; (2) Fuzzy tissue memberships are combined with multi-atlas segmentations to address partial volume effects; (3) MaCRUISE reconstructs topologically consistent cortical surfaces by using the sulci locations from multi-atlas segmentation. Two data sets, one consisting of five subjects with expertly traced landmarks and the other consisting of 100 volumes from elderly subjects are used for validation. Compared with CRUISE, MaCRUISE achieves self-consistent whole brain segmentation and cortical reconstruction without compromising on surface accuracy. MaCRUISE is comparably accurate to FreeSurfer while achieving greater robustness across an elderly population.

  6. Combining Multi-atlas Segmentation with Brain Surface Estimation

    PubMed Central

    Carass, Aaron; Resnick, Susan M.; Pham, Dzung L.; Prince, Jerry L.; Landman, Bennett A.

    2016-01-01

    Whole brain segmentation (with comprehensive cortical and subcortical labels) and cortical surface reconstruction are two essential techniques for investigating the human brain. The two tasks are typically conducted independently, however, which leads to spatial inconsistencies and hinders further integrated cortical analyses. To obtain self-consistent whole brain segmentations and surfaces, FreeSurfer segregates the subcortical and cortical segmentations before and after the cortical surface reconstruction. However, this “segmentation to surface to parcellation” strategy has shown limitations in various situations. In this work, we propose a novel “multi-atlas segmentation to surface” method called Multi-atlas CRUISE (MaCRUISE), which achieves self-consistent whole brain segmentations and cortical surfaces by combining multi-atlas segmentation with the cortical reconstruction method CRUISE. To our knowledge, this is the first work that achieves the reliability of state-of-the-art multi-atlas segmentation and labeling methods together with accurate and consistent cortical surface reconstruction. Compared with previous methods, MaCRUISE has three features: (1) MaCRUISE obtains 132 cortical/subcortical labels simultaneously from a single multi-atlas segmentation before reconstructing volume consistent surfaces; (2) Fuzzy tissue memberships are combined with multi-atlas segmentations to address partial volume effects; (3) MaCRUISE reconstructs topologically consistent cortical surfaces by using the sulci locations from multi-atlas segmentation. Two data sets, one consisting of five subjects with expertly traced landmarks and the other consisting of 100 volumes from elderly subjects are used for validation. Compared with CRUISE, MaCRUISE achieves self-consistent whole brain segmentation and cortical reconstruction without compromising on surface accuracy. MaCRUISE is comparably accurate to FreeSurfer while achieving greater robustness across an elderly

  7. The Prognostic Impact of In-Hospital Change in Mean Platelet Volume in Patients With Non-ST-Segment Elevation Myocardial Infarction.

    PubMed

    Kırış, Tuncay; Yazici, Selcuk; Günaydin, Zeki Yüksel; Akyüz, Şükrü; Güzelburç, Özge; Atmaca, Hüsnü; Ertürk, Mehmet; Nazli, Cem; Dogan, Abdullah

    2016-08-01

    It is unclear whether changes in mean platelet volume (MPV) are associated with total mortality in acute coronary syndromes. We investigated whether the change in MPV predicts total mortality in patients with non-ST-segment elevation myocardial infarction (NSTEMI). We retrospectively analyzed 419 consecutive patients (19 patients were excluded). The remaining patients were categorized as survivors (n = 351) or nonsurvivors (n = 49). Measurements of MPV were performed at admission and after 24 hours. The difference between the 2 measurements was considered as the MPV change (ΔMPV). The end point of the study was total mortality at 1-year follow-up. During the follow-up, there were 49 deaths (12.2%). Admission MPV was comparable in the 2 groups. However, both MPV (9.6 ± 1.4 fL vs 9.2 ± 1.0 fL, P = .044) and ΔMPV (0.40 [0.10-0.70] fL vs 0.70 [0.40-1.20] fL, P < .001) at the first 24 hours were higher in nonsurvivors than survivors. In multivariate analysis, ΔMPV was an independent predictor of total mortality (odds ratio: 1.84, 95% confidence interval: 1.28-2.65, P = .001). An early increase in MPV after admission was independently associated with total mortality in patients with NSTEMI. Such patients may need more effective antiplatelet therapy. PMID:26787684

  8. Thyroid Volume and Its Relation to Anthropometric Measures in a Healthy Cuban Population

    PubMed Central

    Turcios, Silvia; Lence-Anta, Juan J.; Santana, Jose-Luis; Pereda, Celia M.; Velasco, Milagros; Chappe, Mae; Infante, Idalmis; Bustillo, Marlene; García, Anabel; Clero, Enora; Maillard, Stephane; Rodriguez, Regla; Xhaard, Constance; Ren, Yan; Rubino, Carole; Ortiz, Rosa M.; de Vathaire, Florent

    2015-01-01

    Objectives The aim of this study was to describe the thyroid volume in healthy adults by ultrasound and to correlate this volume with some anthropometric measures and other differentiated thyroid cancer risk factors. Study Design Thyroid volume and anthropometric measures were recorded in a sample of 100 healthy adults, including 21 men and 79 women aged 18-50 years, living in a non-iodine-deficient area of Havana city. Results The average thyroid volume was 6.6 ± 0.26 ml; it was higher in men (7.3 ml) than in women (6.4 ml; p = 0.15). In the univariate analysis, thyroid volume was correlated with all anthropometric measures, but in the multivariate analysis, body surface area was found to be the only significant anthropometric parameter. Thyroid volume was also higher in current or former smokers and in persons with blood group AB or B. Conclusion Specific reference values of thyroid volume as a function of body surface area could be used for evaluating thyroid volume in clinical practice. The relation between body surface area and thyroid volume is coherent with what is known about the relation of thyroid volume to thyroid cancer risk, but the same is not true about the relation between thyroid volume and smoking habit. PMID:25960963

  9. The Impact of Hospital Closures and Hospital and Population Characteristics on Increasing Emergency Department Volume: A Geographic Analysis.

    PubMed

    Lee, David C; Carr, Brendan G; Smith, Tony E; Tran, Van C; Polsky, Daniel; Branas, Charles C

    2015-12-01

    Emergency visits are rising nationally, whereas the number of emergency departments is shrinking. However, volume has not increased uniformly at all emergency departments. It is unclear what factors account for this variability in emergency volume growth rates. The objective of this study was to test the association of hospital and population characteristics and the effect of hospital closures with increases in emergency department volume. The study team analyzed emergency department volume at New York State hospitals from 2004 to 2010 using data from cost reports and administrative databases. Multivariate regression was used to evaluate characteristics associated with emergency volume growth. Spatial analytics and distances between hospitals were used in calculating the predicted impact of hospital closures on emergency department use. Among the 192 New York hospitals open from 2004 to 2010, the mean annual increase in emergency department visits was 2.7%, but the range was wide (-5.5% to 11.3%). Emergency volume increased nearly twice as fast at tertiary referral centers (4.8%) and nonurban hospitals (3.7% versus urban at 2.1%) after adjusting for other characteristics. The effect of hospital closures also strongly predicted variation in growth. Emergency volume is increasing faster at specific hospitals: tertiary referral centers, nonurban hospitals, and those near hospital closures. This study provides an understanding of how emergency volume varies among hospitals and predicts the effect of hospital closures in a statewide region. Understanding the impact of these factors on emergency department use is essential to ensure that these populations have access to critical emergency services. PMID:25658768

  10. Adaptive evolution of interleukin-3 (IL3), a gene associated with brain volume variation in general human populations.

    PubMed

    Li, Ming; Huang, Liang; Li, Kaiqin; Huo, Yongxia; Chen, Chunhui; Wang, Jinkai; Liu, Jiewei; Luo, Zhenwu; Chen, Chuansheng; Dong, Qi; Yao, Yong-gang; Su, Bing; Luo, Xiong-jian

    2016-04-01

    Greatly expanded brain volume is one of the most characteristic traits that distinguish humans from other primates. Recent studies have revealed genes responsible for the dramatically enlarged human brain size (i.e., the microcephaly genes), and it has been well documented that many microcephaly genes have undergone accelerated evolution along the human lineage. In addition to being far larger than other primates, human brain volume is also highly variable in general populations. However, the genetic basis underlying human brain volume variation remains elusive and it is not known whether genes regulating human brain volume variation also have experienced positive selection. We have previously shown that genetic variants (near the IL3 gene) on 5q33 were significantly associated with brain volume in Chinese population. Here, we provide further evidence that support the significant association of genetic variants on 5q33 with brain volume. Bioinformatic analyses suggested that rs31480 is likely to be the causal variant among the studied SNPs. Molecular evolutionary analyses suggested that IL3 might have undergone positive selection in primates and humans. Neutrality tests further revealed signatures of positive selection of IL3 in Han Chinese and Europeans. Finally, extended haplotype homozygosity (EHH) and relative EHH analyses showed that the C allele of SNP rs31480 might have experienced recent positive selection in Han Chinese. Our results suggest that IL3 is an important genetic regulator for human brain volume variation and implied that IL3 might have experienced weak or modest positive selection in the evolutionary history of humans, which may be due to its contribution to human brain volume.

  11. The Impact of Hospital Closures and Hospital and Population Characteristics on Increasing Emergency Department Volume: A Geographic Analysis.

    PubMed

    Lee, David C; Carr, Brendan G; Smith, Tony E; Tran, Van C; Polsky, Daniel; Branas, Charles C

    2015-12-01

    Emergency visits are rising nationally, whereas the number of emergency departments is shrinking. However, volume has not increased uniformly at all emergency departments. It is unclear what factors account for this variability in emergency volume growth rates. The objective of this study was to test the association of hospital and population characteristics and the effect of hospital closures with increases in emergency department volume. The study team analyzed emergency department volume at New York State hospitals from 2004 to 2010 using data from cost reports and administrative databases. Multivariate regression was used to evaluate characteristics associated with emergency volume growth. Spatial analytics and distances between hospitals were used in calculating the predicted impact of hospital closures on emergency department use. Among the 192 New York hospitals open from 2004 to 2010, the mean annual increase in emergency department visits was 2.7%, but the range was wide (-5.5% to 11.3%). Emergency volume increased nearly twice as fast at tertiary referral centers (4.8%) and nonurban hospitals (3.7% versus urban at 2.1%) after adjusting for other characteristics. The effect of hospital closures also strongly predicted variation in growth. Emergency volume is increasing faster at specific hospitals: tertiary referral centers, nonurban hospitals, and those near hospital closures. This study provides an understanding of how emergency volume varies among hospitals and predicts the effect of hospital closures in a statewide region. Understanding the impact of these factors on emergency department use is essential to ensure that these populations have access to critical emergency services.

  12. Radiation Therapy After Breast-Conserving Surgery: Does Hospital Surgical Volume Matter? A Population-Based Study in Taiwan

    SciTech Connect

    Chien, Chun-Ru; Pan, I-Wen; Tsai, Yi-Wen; Tsai, Teressa; Liang, Ji-An; Buchholz, Thomas A.; Shih, Ya-Chen Tina

    2012-01-01

    Purpose: To examine the association between hospital surgical volume and the use of radiation therapy (RT) after breast-conserving surgery (BCS) in Taiwan. Methods and Materials: We used claims data from the National Health Insurance program in Taiwan (1997-2005) in this retrospective population-based study. We identified patients with breast cancer, receipt of BCS, use of radiation, and the factors that could potentially associated with the use of RT from enrollment records, and the ICD-9 and billing codes in claims. We conducted logistic regression to examine factors associated with RT use after BCS, and performed subgroup analyses to examine whether the association differs by medical center status or hospital volumes. Results: Among 5,094 patients with newly diagnosed invasive breast cancer who underwent BCS, the rate of RT was significantly lower in low-volume hospitals (74% vs. 82%, p < 0.01). Patients treated in low-volume hospitals were less likely to receive RT after BCS (odds ratio = 0.72, 95% confidence interval = 0.62-0.83). In addition, patients treated after the implementation of the voluntary pay-for-performance policy in 2001 were more likely to receive RT (odds ratio = 1.23; 95% confidence interval = 1.05-1.45). Subgroup analyses indicated that the high-volume effect was limited to hospitals accredited as non-medical centers, and that the effect of the pay-for-performance policy was most pronounced among low-volume hospitals. Conclusions: Using population-based data from Taiwan, our study concluded that hospital surgical volume and pay-for-performance policy are positively associated with RT use after BCS.

  13. A highly variable segment of human subterminal 16p reveals a history of population growth for modern humans outside Africa

    PubMed Central

    Alonso, Santos; Armour, John A. L.

    2001-01-01

    We have sequenced a highly polymorphic subterminal noncoding region from human chromosome 16p13.3, flanking the 5′ end of the hypervariable minisatellite MS205, in 100 chromosomes sampled from different African and Euroasiatic populations. Coalescence analysis indicates that the time to the most recent common ancestor (approximately 1 million years) predates the appearance of anatomically modern human forms. The root of the network describing this variability lies in Africa. African populations show a greater level of diversity and deeper branches. Most Euroasiatic variability seems to have been generated after a recent out-of-Africa range expansion. A history of population growth is the most likely scenario for the Euroasiatic populations. This pattern of nuclear variability can be reconciled with inferences based on mitochondrial DNA. PMID:11158547

  14. Spatial requirements of different life-stages of the loggerhead turtle (Caretta caretta) from a distinct population segment in the northern Gulf of Mexico

    USGS Publications Warehouse

    Lamont, Margaret M.; Putman, Nathan F.; Fujisaki, Ikuko; Hart, Kristen M.

    2015-01-01

    Many marine species have complex life histories that involve disparate developmental, foraging and reproductive habitats and a holistic assessment of the spatial requirements for different life stages is a challenge that greatly complicates their management. Here, we combined data from oceanographic modeling, nesting surveys, and satellite tracking to examine the spatial requirements of different life stages of Loggerhead Turtles (Caretta caretta) from a distinct population segment in the northern Gulf of Mexico. Our findings indicate that after emerging from nesting beaches in Alabama and Northwest Florida, hatchlings disperse widely and the proportion of turtles following a given route varies substantially through time, with the majority (mean of 74.4%) projected to leave the Gulf of Mexico. Adult females use neritic habitat throughout the northern and eastern Gulf of Mexico both during the inter-nesting phase and as post-nesting foraging areas. Movements and habitat use of juveniles and adult males represent a large gap in our knowledge, but given the hatchling dispersal predictions and tracks of post-nesting females it is likely that some Loggerhead Turtles remain in the Gulf of Mexico throughout their life. More than two-thirds of the Gulf provides potential habitat for at least one life-stage of Loggerhead Turtles. These results demonstrate the importance of the Gulf of Mexico to this Distinct Population Segment of Loggerhead Turtles. It also highlights the benefits of undertaking comprehensive studies of multiple life stages simultaneously: loss of individual habitats have the potential to affect several life stages thereby having long-term consequences to population recovery.

  15. Segmenting the Adult Education Market.

    ERIC Educational Resources Information Center

    Aurand, Tim

    1994-01-01

    Describes market segmentation and how the principles of segmentation can be applied to the adult education market. Indicates that applying segmentation techniques to adult education programs results in programs that are educationally and financially satisfying and serve an appropriate population. (JOW)

  16. Compensatory mechanisms in fish populations: Literature reviews: Volume 2, Compensation in fish populations subject to catastrophic impact: Final report

    SciTech Connect

    Jude, D.J.; Mansfield, P.J.; Schneeberger, P.J.; Wojcik, J.A.

    1987-05-01

    This study comprises an extensive literature review, critical evaluations of case histories, and considered recommendations for future research on the mechanisms and extent of compensation by various fish species subject to catastrophic impacts. ''Catastrophic impact'' was defined as an event which removes some limitation (such as food or space) on a fish population. Those events studied included new species introduction, toxic spills, exploitation of specific fish populations, and drawdown. The fish studied each had more than one compensatory mechanism available, and thus were able to respond to a catastrophic event even if an option was removed. Predation, overfishing, competition, disease, and parasitism are all potential catastrophies, but were found not to cause a catastrophic impact (except in special cases). In general, compensatory responses were determined to vary widely, even for species which perform fairly similar functions in an ecosystem. The extensive nature of this study, however, pointed up the many data gaps in the existing literature; recommendations are therefore made for followup research and expansion of ongoing monitoring programs, based on an evaluation of their relative importance.

  17. POPULATION III STAR FORMATION IN LARGE COSMOLOGICAL VOLUMES. I. HALO TEMPORAL AND PHYSICAL ENVIRONMENT

    SciTech Connect

    Crosby, Brian D.; O'Shea, Brian W.; Smith, Britton D.; Turk, Matthew J.; Hahn, Oliver

    2013-08-20

    We present a semi-analytic, computationally inexpensive model to identify halos capable of forming a Population III star in cosmological simulations across a wide range of times and environments. This allows for a much more complete and representative set of Population III star forming halos to be constructed, which will lead to Population III star formation simulations that more accurately reflect the diversity of Population III stars, both in time and halo mass. This model shows that Population III and chemically enriched stars coexist beyond the formation of the first generation of stars in a cosmological simulation until at least z {approx} 10, and likely beyond, though Population III stars form at rates that are 4-6 orders of magnitude lower than chemically enriched stars by z = 10. A catalog of more than 40,000 candidate Population III forming halos were identified, with formation times temporally ranging from z = 30 to z = 10, and ranging in mass from 2.3 Multiplication-Sign 10{sup 5} M{sub Sun} to 1.2 Multiplication-Sign 10{sup 10} M{sub Sun }. At early times, the environment that Population III stars form in is very similar to that of halos hosting chemically enriched star formation. At later times Population III stars are found to form in low-density regions that are not yet chemically polluted due to a lack of previous star formation in the area. Population III star forming halos become increasingly spatially isolated from one another at later times, and are generally closer to halos hosting chemically enriched star formation than to another halo hosting Population III star formation by z {approx} 10.

  18. Prison Population and Policy Choices. Volume 1: Preliminary Report to Congress.

    ERIC Educational Resources Information Center

    Rutherford, Andrew; And Others

    Objectives of the research reported here (phase one of a two-phase project) were (1) to assess the contemporary conditions of American correctional institutions in terms of capacity and adequacy; (2) to search for the causes of fluctuations in prison populations; and (3) to develop methods for projecting future prison populations, with particular…

  19. The Chernobyl papers. Volume 1. Doses to the Soviet population and early health effects studies

    SciTech Connect

    Merwin, S.E.; Balonov, M.I.

    1993-01-01

    The papers in this Volume 1 of a series, discuss studies initiated following the nuclear reactor accident at the Chernobyl Nuclear Power Plant Unit 4. All authored by scientists of the former Soviet Union. Included in Volume 1 are considerations of the internal and external radiation doses received by the inhabitants of the regions recording the highest levels of radioactive contamination (the republics of Russia, Belarus, and Ukraine). Also included are three papers presenting data and analysis pretaining to actual and potential health effects from the accident.

  20. Incorporation of learned shape priors into a graph-theoretic approach with application to the 3D segmentation of intraretinal surfaces in SD-OCT volumes of mice

    NASA Astrophysics Data System (ADS)

    Antony, Bhavna J.; Song, Qi; Abràmoff, Michael D.; Sohn, Eliott; Wu, Xiaodong; Garvin, Mona K.

    2014-03-01

    Spectral-domain optical coherence tomography (SD-OCT) finds widespread use clinically for the detection and management of ocular diseases. This non-invasive imaging modality has also begun to find frequent use in research studies involving animals such as mice. Numerous approaches have been proposed for the segmentation of retinal surfaces in SD-OCT images obtained from human subjects; however, the segmentation of retinal surfaces in mice scans is not as well-studied. In this work, we describe a graph-theoretic segmentation approach for the simultaneous segmentation of 10 retinal surfaces in SD-OCT scans of mice that incorporates learned shape priors. We compared the method to a baseline approach that did not incorporate learned shape priors and observed that the overall unsigned border position errors reduced from 3.58 +/- 1.33 μm to 3.20 +/- 0.56 μm.

  1. Projection models for health-effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume V. SPAHR programmer's guide

    SciTech Connect

    Collins, J.J.; Lundy, R.T.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projections. The model extends several health risk projection models by making realistic assumptions about the population at risk, and thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of response, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, numbers of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projections are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. This volume contains a programmer's guide to SPAHR.

  2. Projection models for health effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume IV. SPAHR user's guide

    SciTech Connect

    Collins, J.J.; Lundy, R.T.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projections. The model extends several health risk projection models by making realistic assumptions about the population at risk, and thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of response, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, number of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projections are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. This volume gives the more advanced user of the SPAHR computer package the information required to create tailor-made programs for addressing specific issues not covered by the three interactive packages. It assumes that the user is familiar with the concepts and terms relating to demography and health risk assessment.

  3. [Comparative study of the volume difference vs. healthy limb, morphological and population description in transfemoral amputees].

    PubMed

    Mendoza-Cruz, Felipe; Rodríguez-Reyes, Gerardo; Galván Duque-Gastélum, Carlos; Alvarez-Camacho, Michelín

    2014-07-01

    Knowledge of the general characteristics and physical condition that keeps the transfemoral amputation stump to select and adapt appropriate type of prosthesis to restore a walking pattern amputee patient acceptable and useful design parameters set to propose new prosthetic systems. In this paper, the degree of difference between the volumes of the limb stump and healthy as well as morphological features occurred more frequently in the stumps of transfemoral amputees who were treated at the Laboratory of Orthotics and Prosthetics (LOP), Instituto Nacional de Rehabilitación (INR) in 2008. It captured all patients with unilateral transfemoral amputation left and right, over 18 years old, both sexes, use of hearing candidates were evaluated clinically and took three measurements of the circumferences at different wavelengths and the limb stump healthy, were calculated volumes of both sides using the mathematical model of the truncated cone and analyzed in three groups according to the level of amputation (proximal, middle and distal third). We obtained 49 patients, 39 men and 10 women, the difference stump volume compared to healthy limb volume per group were: 44.9% proximal third, middle third and distal 26.5%, 21.1%, the frequency of diagnostic data showed a stump right transfemoral amputees, due to metabolic, without use of prostheses, the most common morphological features indicate that the stump has a conical shape and size distal third, whose tissue is semi-flaccid consistency, the scar is not adhered to deep planes and shows a negative tinel, the mattress soft tissue is 2.15 ± 1.3 cm and physically presents a force level 4 in the clinical rating scale Daniels. The data are consistent with other studies comparing the percentage of the volume change with the percentages of reduced diameters transfemoral stump muscle, likewise agrees most amputees incidence of diabetes mellitus with other studies, cataloging it eat first cause amputation. The general description

  4. [Comparative study of the volume difference vs. healthy limb, morphological and population description in transfemoral amputees].

    PubMed

    Mendoza-Cruz, Felipe; Rodríguez-Reyes, Gerardo; Galván Duque-Gastélum, Carlos; Alvarez-Camacho, Michelín

    2014-07-01

    Knowledge of the general characteristics and physical condition that keeps the transfemoral amputation stump to select and adapt appropriate type of prosthesis to restore a walking pattern amputee patient acceptable and useful design parameters set to propose new prosthetic systems. In this paper, the degree of difference between the volumes of the limb stump and healthy as well as morphological features occurred more frequently in the stumps of transfemoral amputees who were treated at the Laboratory of Orthotics and Prosthetics (LOP), Instituto Nacional de Rehabilitación (INR) in 2008. It captured all patients with unilateral transfemoral amputation left and right, over 18 years old, both sexes, use of hearing candidates were evaluated clinically and took three measurements of the circumferences at different wavelengths and the limb stump healthy, were calculated volumes of both sides using the mathematical model of the truncated cone and analyzed in three groups according to the level of amputation (proximal, middle and distal third). We obtained 49 patients, 39 men and 10 women, the difference stump volume compared to healthy limb volume per group were: 44.9% proximal third, middle third and distal 26.5%, 21.1%, the frequency of diagnostic data showed a stump right transfemoral amputees, due to metabolic, without use of prostheses, the most common morphological features indicate that the stump has a conical shape and size distal third, whose tissue is semi-flaccid consistency, the scar is not adhered to deep planes and shows a negative tinel, the mattress soft tissue is 2.15 ± 1.3 cm and physically presents a force level 4 in the clinical rating scale Daniels. The data are consistent with other studies comparing the percentage of the volume change with the percentages of reduced diameters transfemoral stump muscle, likewise agrees most amputees incidence of diabetes mellitus with other studies, cataloging it eat first cause amputation. The general description

  5. Wife battering in Asian American communities. Identifying the service needs of an overlooked segment of the U.S. population.

    PubMed

    Huisman, K A

    1996-09-01

    This study examined the specific needs of Asian women who are battered, and explored the various structural and cultural constraints that inhibit these women from securing help from mainstream social service providers in the US. Data were gathered from interviews that were conducted with 18 Asian community activists and service providers throughout the US. The results showed that Asian women who were battered, particularly recently arrived immigrant and refugee women, have needs that differ markedly from most battered women in the general US population. The needs of the refugee women center on language issues, cultural issues, immigration issues, and structural issues. Moreover, there are several internal and external forces that work in tandem to keep the needs of Asian women from being formally included in the mainstream battered women's movement. The internal forces include cultural beliefs and practices, while the external forces include stereotype about Asians, such as the ¿model minority myth,¿ lack of funding for programs for battered Asian women, US immigration laws, the historical exclusion of women of color from the mainstream feminist movement in the US, and the prevalence of sexism and racism in the American society. Finally, recommendations for social providers to better meet these needs are provided.

  6. Improving cerebellar segmentation with statistical fusion

    NASA Astrophysics Data System (ADS)

    Plassard, Andrew J.; Yang, Zhen; Prince, Jerry L.; Claassen, Daniel O.; Landman, Bennett A.

    2016-03-01

    The cerebellum is a somatotopically organized central component of the central nervous system well known to be involved with motor coordination and increasingly recognized roles in cognition and planning. Recent work in multiatlas labeling has created methods that offer the potential for fully automated 3-D parcellation of the cerebellar lobules and vermis (which are organizationally equivalent to cortical gray matter areas). This work explores the trade offs of using different statistical fusion techniques and post hoc optimizations in two datasets with distinct imaging protocols. We offer a novel fusion technique by extending the ideas of the Selective and Iterative Method for Performance Level Estimation (SIMPLE) to a patch-based performance model. We demonstrate the effectiveness of our algorithm, Non- Local SIMPLE, for segmentation of a mixed population of healthy subjects and patients with severe cerebellar anatomy. Under the first imaging protocol, we show that Non-Local SIMPLE outperforms previous gold-standard segmentation techniques. In the second imaging protocol, we show that Non-Local SIMPLE outperforms previous gold standard techniques but is outperformed by a non-locally weighted vote with the deeper population of atlases available. This work advances the state of the art in open source cerebellar segmentation algorithms and offers the opportunity for routinely including cerebellar segmentation in magnetic resonance imaging studies that acquire whole brain T1-weighted volumes with approximately 1 mm isotropic resolution.

  7. Health literacy on tuberculosis amongst vulnerable segment of population: special reference to Saharia tribe in central India

    PubMed Central

    Muniyandi, M.; Rao, V.G.; Bhat, J.; Yadav, R.; Sharma, R.K.; Bhondeley, M.K.

    2015-01-01

    Background & objectives: Health literacy on tuberculosis (TB) is an understanding about TB to perform activities with regard to prevention, diagnosis and treatment. We undertook a study to assess the health literacy on TB among one of the vulnerable tribal groups (Saharia) in central India. Methods: In this cross-sectional study, 2721 individuals aged >15 yr from two districts of Madhya Pradesh State of India were interviewed at their residence during December 2012-July 2013. By using a short-form questionnaire, health literacy on cause, symptoms, mode of transmission, diagnosis, treatment and prevention of TB was assessed. Results: Of the 2721 (Gwalior 1381; Shivpuri 1340) individuals interviewed; 76 per cent were aged <45 yr. Living condition was very poor (62% living in huts/katcha houses, 84 per cent with single room, 89 per cent no separate kitchen, 97 per cent used wood/crop as a fuel). Overall literacy rate was 19 per cent, and 22 per cent had >7 members in a house. Of the 2721 respondents participated, 52 per cent had never heard of TB; among them 8 per cent mentioned cough as a symptom, 64 per cent mentioned coughing up blood, and 91 per cent knew that TB diagnosis, and treatment facilities were available in both government and private hospitals. Health literacy score among participants who had heard of TB was <40 per cent among 36 per cent of respondents, 41-60 per cent among 54 per cent and >60 per cent among 8 per cent of respondents. Interpretation & conclusions: The finding that nearly half of the respondents had not heard of TB indicated an important gap in education regarding TB in this vulnerable population. There is an urgent need to implement targeted interventions to educate this group for better TB control. PMID:26139783

  8. Age estimation in an Indian population using pulp/tooth volume ratio of mandibular canines obtained from cone beam computed tomography.

    PubMed

    Jagannathan, N; Neelakantan, P; Thiruvengadam, C; Ramani, P; Premkumar, P; Natesan, A; Herald, J S; Luder, H U

    2011-07-01

    The present study assessed the suitability of pulp/tooth volume ratio of mandibular canines for age prediction in an Indian population. Volumetric reconstruction of scanned images of mandibular canines from 140 individuals (aged ten - 70 years), using computed tomography was used to measure pulp and tooth volumes. Age calculated using a formula reported earlier for a Belgian sample, resulted in errors > ten years in almost 86% of the study population. The regression equation obtained for the Indian population: Age = 57.18 + (- 413.41 x pulp/tooth volume ratio), was applied to an independent control group (n = 48), and this resulted in mean absolute errors of 8.54 years which was significantly (p < 0.05) lower than those derived with the Belgian formula. The pulp/tooth volume ratio is a useful indicator of age, although correlations may vary in different populations and hence, specific formulae should be applied for the estimates. PMID:21841263

  9. Population dose commitments due to radioactive releases from nuclear power plant sites in 1981. Volume 3

    SciTech Connect

    Baker, D.A.; Peloquin, R.A.

    1985-01-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1981. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teenager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways from 48 sites ranged from a high of 20 person-rem to a low of 0.008 person-rem with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 160 person-rem for the 98 million people considered at risk.

  10. Population dose commitments due to radioactive releases from nuclear power plant sites in 1982. Volume 4

    SciTech Connect

    Baker, D.A.; Peloquin, R.A.

    1986-06-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1982. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 51 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitments from both liquid and airborne pathways ranged from a high of 30 person-rem to a low of 0.007 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 130 person-rem for the 100 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 6 x 10/sup -7/ mrem to a high of 0.06 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites.

  11. A population study on risk factors for insomnia among adult Japanese women: a possible effect of road traffic volume.

    PubMed

    Kageyama, T; Kabuto, M; Nitta, H; Kurokawa, Y; Taira, K; Suzuki, S; Takemoto, T

    1997-11-01

    In an effort to identify risk factors for insomnia and determine the contribution of nightime road traffic volume to insomnia in the general population, a questionnaire survey was carried out among 3,600 adult Japanese women living in eight urban residential areas. The crude prevalence rate of insomnia was 11.2%. Multivariate analysis revealed that aging, living with a child/children aged six or younger, undergoing medical treatment, experiencing major life events, having an irregular bedtime, having a sleep apnealike symptom, and living near a road with a heavy volume of traffic are risk factors for insomnia. Taking into account other risk factors, there was a level-response relationship between the nighttime traffic volume of main roads and the risk of insomnia in the subjects living in the zones 0-20 m from these roads. These results suggest that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas. To confirm this, a further study on noise exposure is needed.

  12. Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 4: Mission peculiar spacecraft segment and module specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The specifications for the Earth Observatory Satellite (EOS) peculiar spacecraft segment and associated subsystems and modules are presented. The specifications considered include the following: (1) wideband communications subsystem module, (2) mission peculiar software, (3) hydrazine propulsion subsystem module, (4) solar array assembly, and (5) the scanning spectral radiometer.

  13. Population dose commitments due to radioactive releases from nuclear power plant sites in 1988. Volume 10

    SciTech Connect

    Baker, D.A.

    1992-01-01

    Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1988. Fifty-year commitments for a one-year exposure from both liquid and atmospheric releases were calculated for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 71 reactor sites. This report tabulates the results of these calculations, showing the dose commitments for both water and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total collective dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 16 person-rem to a low of 0.0011 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 1.1 person-rem. The total population dose for all sites was estimated at 75 person-rem for the 150 million people considered at risk. The site average individual dose commitment from all pathways ranged from a low of 3 {times} 10{sup {minus}7} mrem to a high of 0.02 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites. However, licensee calculation of doses to the maximally exposed individual at some sites indicated values of up to approximately 100 times average individual doses (on the order of a few millirem per year).

  14. Impact of entrainment and impingement on fish populations in the Hudson River estuary. Volume I. Entrainment-impact estimates for six fish populations inhabiting the Hudson River estuary

    SciTech Connect

    Boreman, J.; Barnthouse, L.W.; Vaughn, D.S.; Goodyear, C.P.; Christensen, S.W.; Kumar, K.D.; Kirk, B.L.; Van Winkle, W.

    1982-01-01

    This volume is concerned with the estimation of the direct (or annual) entrainment impact of power plants on populations of striped bass, white perch, Alosa spp. (blueback herring and alewife), American shad, Atlantic tomcod, and bay anchovy in the Hudson River estuary. Entrainment impact results from the killing of fish eggs, larvae, and young juveniles that are contained in the cooling water cycled through a power plant. An Empirical Transport Model (ETM) is presented as the means of estimating a conditional entrainment mortality rate (defined as the fraction of a year class which would be killed due to entrainment in the absence of any other source of mortality). Most of this volume is concerned with the estimation of several parameters required by the ETM: physical input parameters (e.g., power-plant withdrawal flow rates); the longitudinal distribution of ichthyoplankton in time and space; the duration of susceptibility of the vulnerable organisms; the W-factors, which express the ratios of densities of organisms in power plant intakes to densities of organisms in the river; and the entrainment mortality factors (f-factors), which express the probability that an organism will be killed if it is entrained. Once these values are obtained, the ETM is used to estimate entrainment impact for both historical and projected conditions.

  15. Projection models for health-effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume II. SPAHR introductory guide

    SciTech Connect

    Collins, J.J.; Lundy, R.T.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projections. The model extends several health risk projection models by making realistic assumptions about the population at risk, and thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of responses, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, number of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projects are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. This volume gives the user of the SPAHR program the information required to operate the program when it is up and running on the computer. It assumes that the user is familiar with the concepts and terms relating to demography and health risk assessment. It contains a brief description of all commands and options available in SPAHR, as well as a user-oriented description of the structure and operation of the control system and language processor.

  16. Photic Volume in Photobioreactors Supporting Ultrahigh Population Densities of the Photoautotroph Spirulina platensis.

    PubMed

    Gitelson, A; Qiuang, H; Richmond, A

    1996-05-01

    Characterization of the photic zone and light penetration depth in cultures with ultrahigh cell densities represents a major issue in mass cultures of phytoautotrophic microorganisms grown in enclosed photobioreactors. In a study of the effect of underwater optical properties on the penetration depth of photosynthetically active radiation, the inherent optical properties of algal suspensions, i.e., absorption and scattering coefficients, as well as their apparent optical properties, i.e., the reflectance and the vertical attenuation coefficient of downwelling irradiance, were determined by using high-spectral-resolution radiometric measurements. The vertical attenuation coefficient was used to estimate quantitatively the depth of light penetration into a reactor containing an ultrahigh cell density (chlorophyll concentration, up to 300,000 mg m(sup-3)). For such a high cell density, the photic volume in the reactor was found to be extremely small; nevertheless, it differed between the blue and red light (less than 0.06 mm) and the green light (about 0.5 mm). This suggests a singular role for green light under the unique circumstances existing in ultrahigh-cell-density cultures of photoautotrophs.

  17. Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 3: General purpose spacecraft segment and module specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The specifications for the Earth Observatory Satellite (EOS) general purpose aircraft segment are presented. The satellite is designed to provide attitude stabilization, electrical power, and a communications data handling subsystem which can support various mission peculiar subsystems. The various specifications considered include the following: (1) structures subsystem, (2) thermal control subsystem, (3) communications and data handling subsystem module, (4) attitude control subsystem module, (5) power subsystem module, and (6) electrical integration subsystem.

  18. Genetic, psychosocial and clinical factors associated with hippocampal volume in the general population

    PubMed Central

    Janowitz, D; Schwahn, C; Borchardt, U; Wittfeld, K; Schulz, A; Barnow, S; Biffar, R; Hoffmann, W; Habes, M; Homuth, G; Nauck, M; Hegenscheid, K; Lotze, M; Völzke, H; Freyberger, H J; Debette, S; Grabe, H J

    2014-01-01

    The hippocampus—crucial for memory formation, recall and mood regulation—is involved in the pathophysiology of dementia and depressive disorders. Recent genome-wide association studies (GWAS) have identified five genetic loci associated with hippocampal volume (HV). Previous studies have described psychosocial and clinical factors (for example, smoking, type 2 diabetes and hypertension) to have an impact on HV. However, the interplay between genetic, psychosocial and clinical factors on the HV remains unclear. Still, it is likely that genetic variants and clinical or psychosocial factors jointly act in modifying HV; it might be possible they even interact. Knowledge of these factors might help to quantify ones individual risk of or rather resilience against HV loss. We investigated subjects (N=2463; 55.7% women; mean age 53 years) from the Study of Health in Pomerania (SHIP-2; SHIP-TREND-0) who underwent whole-body magnetic resonance imaging (MRI) and genotyping. HVs were estimated with FreeSurfer. For optimal nonlinear model fitting, we used regression analyses with restricted cubic splines. Genetic variants and associated psychosocial or clinical factors were jointly assessed for potential two-way interactions. We observed associations between HV and gender (P<0.0001), age (P<0.0001), body height (P<0.0001), education (P=0.0053), smoking (P=0.0058), diastolic blood pressure (P=0.0211), rs7294919 (P=0.0065), rs17178006 (P=0.0002), rs6581612 (P=0.0036), rs6741949 (P=0.0112) and rs7852872 (P=0.0451). In addition, we found three significant interactions: between rs7294919 and smoking (P=0.0473), rs7294919 and diastolic blood pressure (P=0.0447) and between rs7852872 and rs6581612 (P=0.0114). We suggest that these factors might have a role in the individual susceptibility to hippocampus-associated disorders. PMID:25313508

  19. Global fractional anisotropy and mean diffusivity together with segmented brain volumes assemble a predictive discriminant model for young and elderly healthy brains: a pilot study at 3T

    PubMed Central

    Garcia-Lazaro, Haydee Guadalupe; Becerra-Laparra, Ivonne; Cortez-Conradis, David; Roldan-Valadez, Ernesto

    2016-01-01

    Summary Several parameters of brain integrity can be derived from diffusion tensor imaging. These include fractional anisotropy (FA) and mean diffusivity (MD). Combination of these variables using multivariate analysis might result in a predictive model able to detect the structural changes of human brain aging. Our aim was to discriminate between young and older healthy brains by combining structural and volumetric variables from brain MRI: FA, MD, and white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF) volumes. This was a cross-sectional study in 21 young (mean age, 25.71±3.04 years; range, 21–34 years) and 10 elderly (mean age, 70.20±4.02 years; range, 66–80 years) healthy volunteers. Multivariate discriminant analysis, with age as the dependent variable and WM, GM and CSF volumes, global FA and MD, and gender as the independent variables, was used to assemble a predictive model. The resulting model was able to differentiate between young and older brains: Wilks’ λ = 0.235, χ2 (6) = 37.603, p = .000001. Only global FA, WM volume and CSF volume significantly discriminated between groups. The total accuracy was 93.5%; the sensitivity, specificity and positive and negative predictive values were 91.30%, 100%, 100% and 80%, respectively. Global FA, WM volume and CSF volume are parameters that, when combined, reliably discriminate between young and older brains. A decrease in FA is the strongest predictor of membership of the older brain group, followed by an increase in WM and CSF volumes. Brain assessment using a predictive model might allow the follow-up of selected cases that deviate from normal aging. PMID:27027893

  20. Automated prostate segmentation in whole-body MRI scans for epidemiological studies

    NASA Astrophysics Data System (ADS)

    Habes, Mohamad; Schiller, Thilo; Rosenberg, Christian; Burchardt, Martin; Hoffmann, Wolfgang

    2013-09-01

    The whole prostatic volume (PV) is an important indicator for benign prostate hyperplasia. Correlating the PV with other clinical parameters in a population-based prospective cohort study (SHIP-2) requires valid prostate segmentation in a large number of whole-body MRI scans. The axial proton density fast spin echo fat saturated sequence is used for prostate screening in SHIP-2. Our automated segmentation method is based on support vector machines (SVM). We used three-dimensional neighborhood information to build classification vectors from automatically generated features and randomly selected 16 MR examinations for validation. The Hausdorff distance reached a mean value of 5.048 ± 2.413, and a mean value of 5.613 ± 2.897 compared to manual segmentation by observers A and B. The comparison between volume measurement of SVM-based segmentation and manual segmentation of observers A and B depicts a strong correlation resulting in Spearman’s rank correlation coefficients (ρ) of 0.936 and 0.859, respectively. Our automated methodology based on SVM for prostate segmentation can segment the prostate in WBI scans with good segmentation quality and has considerable potential for integration in epidemiological studies.

  1. [Population].

    PubMed

    1979-01-01

    Data on the population of Venezuela between 1975 and 1977 are presented in descriptive tables and graphs. Information is included on the employed population according to category, sex, and type of economic activity, and by sex, age, and area on the employment rate and the total, the economically active, and the unemployed population.

  2. Rediscovering market segmentation.

    PubMed

    Yankelovich, Daniel; Meer, David

    2006-02-01

    In 1964, Daniel Yankelovich introduced in the pages of HBR the concept of nondemographic segmentation, by which he meant the classification of consumers according to criteria other than age, residence, income, and such. The predictive power of marketing studies based on demographics was no longer strong enough to serve as a basis for marketing strategy, he argued. Buying patterns had become far better guides to consumers' future purchases. In addition, properly constructed nondemographic segmentations could help companies determine which products to develop, which distribution channels to sell them in, how much to charge for them, and how to advertise them. But more than 40 years later, nondemographic segmentation has become just as unenlightening as demographic segmentation had been. Today, the technique is used almost exclusively to fulfill the needs of advertising, which it serves mainly by populating commercials with characters that viewers can identify with. It is true that psychographic types like "High-Tech Harry" and "Joe Six-Pack" may capture some truth about real people's lifestyles, attitudes, self-image, and aspirations. But they are no better than demographics at predicting purchase behavior. Thus they give corporate decision makers very little idea of how to keep customers or capture new ones. Now, Daniel Yankelovich returns to these pages, with consultant David Meer, to argue the case for a broad view of nondemographic segmentation. They describe the elements of a smart segmentation strategy, explaining how segmentations meant to strengthen brand identity differ from those capable of telling a company which markets it should enter and what goods to make. And they introduce their "gravity of decision spectrum", a tool that focuses on the form of consumer behavior that should be of the greatest interest to marketers--the importance that consumers place on a product or product category.

  3. Population.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

  4. Psychiatrists' caseload volume, length of stay and mental healthcare readmission rates: a three-year population-based study.

    PubMed

    Lin, Herng-Ching; Lee, Hsin-Chien

    2009-03-31

    This study aimed to compare psychiatrists' in-patient caseload volume with length of stay (LOS) and 30-day readmission rates in Taiwan. We hypothesized that high-volume psychiatrists would be associated with shorter LOS and lower 30-day readmission rates. The sample of 66,959 patients hospitalized for the first time for mental disorders was taken from Taiwan's 2001-2003 National Health Insurance Research Database and categorized into four patient groups according to attending psychiatrists' caseload volume. A total of 21,669 (32.4%) of the patients sampled were readmitted within a 30-day period, with the mean LOS being 24.0 (+/-19.5) days. As caseload volume increased, there was a corresponding increase in the adjusted odds ratio for 30-day readmission rates. The regression analysis reveals adjusted LOS for patients treated by psychiatrists with medium caseload volumes was 1.22 days shorter than that for patients treated by low caseload volume psychiatrists. The adjusted LOS for patients seeing high caseload volume psychiatrists was 2.03 days shorter than for those seeing psychiatrists with low caseload volumes; and for the very-high-volume group, it was 7.59 days shorter. Although the findings confirm our hypothesis regarding LOS, they do not support our hypothesis regarding the relationship between psychiatrists' caseload volume and readmission rates. PMID:19195715

  5. 3D-Assisted Quantitative Assessment of Orbital Volume Using an Open-Source Software Platform in a Taiwanese Population

    PubMed Central

    Shyu, Victor Bong-Hang; Hsu, Chung-En; Chen, Chih-hao; Chen, Chien-Tzung

    2015-01-01

    Orbital volume evaluation is an important part of pre-operative assessments in orbital trauma and congenital deformity patients. The availability of the affordable, open-source software, OsiriX, as a tool for preoperative planning increased the popularity of radiological assessments by the surgeon. A volume calculation method based on 3D volume rendering-assisted region-of-interest computation was used to determine the normal orbital volume in Taiwanese patients after reorientation to the Frankfurt plane. Method one utilized 3D points for intuitive orbital rim outlining. The mean normal orbital volume for left and right orbits was 24.3±1.51 ml and 24.7±1.17 ml in male and 21.0±1.21 ml and 21.1±1.30 ml in female subjects. Another method (method two) based on the bilateral orbital lateral rim was also used to calculate orbital volume and compared with method one. The mean normal orbital volume for left and right orbits was 19.0±1.68 ml and 19.1±1.45 ml in male and 16.0±1.01 ml and 16.1±0.92 ml in female subjects. The inter-rater reliability and intra-rater measurement accuracy between users for both methods was found to be acceptable for orbital volume calculations. 3D-assisted quantification of orbital volume is a feasible technique for orbital volume assessment. The normal orbital volume can be used as controls in cases of unilateral orbital reconstruction with a mean size discrepancy of less than 3.1±2.03% in females and 2.7±1.32% in males. The OsiriX software can be used reliably by the individual surgeon as a comprehensive preoperative planning and imaging tool for orbital volume measurement and computed tomography reorientation. PMID:25774683

  6. Segmental neuromyotonia

    PubMed Central

    Panwar, Ajay; Junewar, Vivek; Sahu, Ritesh; Shukla, Rakesh

    2015-01-01

    Unilateral focal neuromyotonia has been rarely reported in fingers or extraocular muscles. We report a case of segmental neuromyotonia in a 20-year-old boy who presented to us with intermittent tightness in right upper limb. Electromyography revealed myokymic and neuromyotonic discharges in proximal as well as distal muscles of the right upper limb. Patient's symptoms responded well to phenytoin therapy. Such an atypical involvement of two contiguous areas of a single limb in neuromyotonia has not been reported previously. Awareness of such an atypical presentation of the disease can be important in timely diagnosis and treatment of a patient. PMID:26167035

  7. Segmentation of Unstructured Datasets

    NASA Technical Reports Server (NTRS)

    Bhat, Smitha

    1996-01-01

    Datasets generated by computer simulations and experiments in Computational Fluid Dynamics tend to be extremely large and complex. It is difficult to visualize these datasets using standard techniques like Volume Rendering and Ray Casting. Object Segmentation provides a technique to extract and quantify regions of interest within these massive datasets. This thesis explores basic algorithms to extract coherent amorphous regions from two-dimensional and three-dimensional scalar unstructured grids. The techniques are applied to datasets from Computational Fluid Dynamics and from Finite Element Analysis.

  8. Vibration damping for the Segmented Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Maly, Joseph R.; Yingling, Adam J.; Griffin, Steven F.; Agrawal, Brij N.; Cobb, Richard G.; Chambers, Trevor S.

    2012-09-01

    The Segmented Mirror Telescope (SMT) at the Naval Postgraduate School (NPS) in Monterey is a next-generation deployable telescope, featuring a 3-meter 6-segment primary mirror and advanced wavefront sensing and correction capabilities. In its stowed configuration, the SMT primary mirror segments collapse into a small volume; once on location, these segments open to the full 3-meter diameter. The segments must be very accurately aligned after deployment and the segment surfaces are actively controlled using numerous small, embedded actuators. The SMT employs a passive damping system to complement the actuators and mitigate the effects of low-frequency (<40 Hz) vibration modes of the primary mirror segments. Each of the six segments has three or more modes in this bandwidth, and resonant vibration excited by acoustics or small disturbances on the structure can result in phase mismatches between adjacent segments thereby degrading image quality. The damping system consists of two tuned mass dampers (TMDs) for each of the mirror segments. An adjustable TMD with passive magnetic damping was selected to minimize sensitivity to changes in temperature; both frequency and damping characteristics can be tuned for optimal vibration mitigation. Modal testing was performed with a laser vibrometry system to characterize the SMT segments with and without the TMDs. Objectives of this test were to determine operating deflection shapes of the mirror and to quantify segment edge displacements; relative alignment of λ/4 or better was desired. The TMDs attenuated the vibration amplitudes by 80% and reduced adjacent segment phase mismatches to acceptable levels.

  9. A qualitative exploration of attitudes towards alcohol, and the role of parents and peers of two alcohol-attitude-based segments of the adolescent population

    PubMed Central

    2014-01-01

    Background An earlier study using social marketing and audience segmentation distinguished five segments of Dutch adolescents aged 12–18 years based on their attitudes towards alcohol. The present, qualitative study focuses on two of these five segments (‘ordinaries’ and ‘ordinary sobers’) and explores the attitudes of these two segments towards alcohol, and the role of parents and peers in their alcohol use in more detail. Methods This qualitative study was conducted in the province of North-Brabant, the Netherlands. With a 28-item questionnaire, segments of adolescents were identified. From the ordinaries and ordinary sobers who were willing to participate in a focus group, 55 adolescents (30 ordinaries and 25 ordinary sobers) were selected and invited to participate. Finally, six focus groups were conducted with 12–17 year olds, i.e., three interviews with 17 ordinaries and three interviews with 20 ordinary sobers at three different high schools. Results The ordinaries thought that drinking alcohol was fun and relaxing. Curiosity was an important factor in starting to drink alcohol. Peer pressure played a role, e.g., it was difficult not to drink when peers were drinking. Most parents advised their child to drink a small amount only. The attitude of ordinary sobers towards alcohol was that drinking alcohol was stupid; moreover, they did not feel the need to drink. Most parents set strict rules and prohibited the use of alcohol before the age of 16. Conclusions Qualitative insight into the attitudes towards alcohol and the role played by parents and peers, revealed differences between ordinaries and ordinary sobers. Based on these differences and on health education theories, starting points for the development of interventions, for both parents and adolescents, are formulated. Important starting points for interventions targeting ordinaries are reducing perceived peer pressure and learning to make one’s own choices. For the ordinary sobers, an

  10. Salient Segmentation of Medical Time Series Signals

    PubMed Central

    Woodbridge, Jonathan; Lan, Mars; Sarrafzadeh, Majid; Bui, Alex

    2016-01-01

    Searching and mining medical time series databases is extremely challenging due to large, high entropy, and multidimensional datasets. Traditional time series databases are populated using segments extracted by a sliding window. The resulting database index contains an abundance of redundant time series segments with little to no alignment. This paper presents the idea of “salient segmentation”. Salient segmentation is a probabilistic segmentation technique for populating medical time series databases. Segments with the lowest probabilities are considered salient and are inserted into the index. The resulting index has little redundancy and is composed of aligned segments. This approach reduces index sizes by more than 98% over conventional sliding window techniques. Furthermore, salient segmentation can reduce redundancy in motif discovery algorithms by more than 85%, yielding a more succinct representation of a time series signal.

  11. The Effect of Burn Center Volume on Mortality in a Pediatric Population: An Analysis of the National Burn Repository

    PubMed Central

    Hodgman, Erica I.; Saeman, Melody R.; Subramanian, Madhu

    2016-01-01

    The effect of burn center volume on mortality has been demonstrated in adults. The authors sought to evaluate whether such a relationship existed in burned children. The National Burn Repository, a voluntary registry sponsored by the American Burn Association, was queried for all data points on patients aged 18 years or less and treated from 2002 to 2011. Facilities were divided into quartiles based on average annual burn volume. Demographics and clinical characteristics were compared across groups, and univariate and multivariate logistic regressions were performed to evaluate relationships between facility volume, patient characteristics, and mortality. The authors analyzed 38,234 patients admitted to 88 unique facilities. Children under age 4 years or with larger burns were more likely to be managed at high-volume and very high–volume centers (57.12 and 53.41%, respectively). Overall mortality was low (0.85%). Comparing mortality across quartiles demonstrated improved unadjusted mortality rates at the low- and high-volume centers compared with the medium-volume and very high–volume centers although univariate logistic regression did not find a significant relationship. However, multivariate analysis identified burn center volume as a significant predictor of decreased mortality after controlling for patient characteristics including age, mechanism of injury, burn size, and presence of inhalation injury. Mortality among pediatric burn patients is low and was primarily related to patient and injury characteristics, such as burn size, inhalation injury, and burn cause. Average annual admission rate had a significant but small effect on mortality when injury characteristics were considered. PMID:26146907

  12. Example based lesion segmentation

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; He, Qing; Carass, Aaron; Jog, Amod; Cuzzocreo, Jennifer L.; Reich, Daniel S.; Prince, Jerry; Pham, Dzung

    2014-03-01

    Automatic and accurate detection of white matter lesions is a significant step toward understanding the progression of many diseases, like Alzheimer's disease or multiple sclerosis. Multi-modal MR images are often used to segment T2 white matter lesions that can represent regions of demyelination or ischemia. Some automated lesion segmentation methods describe the lesion intensities using generative models, and then classify the lesions with some combination of heuristics and cost minimization. In contrast, we propose a patch-based method, in which lesions are found using examples from an atlas containing multi-modal MR images and corresponding manual delineations of lesions. Patches from subject MR images are matched to patches from the atlas and lesion memberships are found based on patch similarity weights. We experiment on 43 subjects with MS, whose scans show various levels of lesion-load. We demonstrate significant improvement in Dice coefficient and total lesion volume compared to a state of the art model-based lesion segmentation method, indicating more accurate delineation of lesions.

  13. Example Based Lesion Segmentation

    PubMed Central

    Roy, Snehashis; He, Qing; Carass, Aaron; Jog, Amod; Cuzzocreo, Jennifer L.; Reich, Daniel S.; Prince, Jerry; Pham, Dzung

    2016-01-01

    Automatic and accurate detection of white matter lesions is a significant step toward understanding the progression of many diseases, like Alzheimer’s disease or multiple sclerosis. Multi-modal MR images are often used to segment T2 white matter lesions that can represent regions of demyelination or ischemia. Some automated lesion segmentation methods describe the lesion intensities using generative models, and then classify the lesions with some combination of heuristics and cost minimization. In contrast, we propose a patch-based method, in which lesions are found using examples from an atlas containing multi-modal MR images and corresponding manual delineations of lesions. Patches from subject MR images are matched to patches from the atlas and lesion memberships are found based on patch similarity weights. We experiment on 43 subjects with MS, whose scans show various levels of lesion-load. We demonstrate significant improvement in Dice coefficient and total lesion volume compared to a state of the art model-based lesion segmentation method, indicating more accurate delineation of lesions.

  14. Depressive symptoms, antidepressant use, and brain volumes on MRI in a population-based cohort of old persons without dementia.

    PubMed

    Geerlings, Mirjam I; Brickman, Adam M; Schupf, Nicole; Devanand, Davangere P; Luchsinger, José A; Mayeux, Richard; Small, Scott A

    2012-01-01

    We examined whether late-life depression, including depressive symptoms and antidepressant use, was associated with smaller total brain volume, smaller hippocampal volume, and larger white matter hyperintensity (WMH) volume in a large community-based cohort of old persons without dementia. Within the Washington/Hamilton Height-Inwood Columbia Aging Project (WHICAP), a community-based cohort study in northern Manhattan, 630 persons without dementia (mean age 80 years, SD = 5) had volumetric measures of the total brain, hippocampus, and WMH at 1.5 Tesla MRI and data on current depression, defined as a score of 4 or higher on the 10-item Center for Epidemiologic Studies-Depression (CES-D) scale, or use of antidepressants. Multiple linear regression analyses adjusted for age, gender, ethnicity, education, cardiovascular disease history, and MRI parameters showed that subjects with current depression had smaller relative total brain volume (B = -0.86%; 95% CI -1.68 to -0.05%; p < 0.05), smaller relative hippocampal volume (B = -0.07 ml; 95% CI -0.14 to 0.00 ml; p = 0.05), and larger relative WMH volume (natural logtransformed B = 0.19 ml; 95% CI 0.02 to 0.35 ml; p < 0.05). When examined separately, antidepressant use was significantly associated with smaller total brain, smaller hippocampal, and larger WMH volume, while high CES-D scores were not significantly associated with any of the brain measures, although the direction of association was similar as for antidepressant use. With the caveat that analyses were cross-sectional and we had no formal diagnosis of depression, our findings suggest that in this community-based sample of old persons without dementia, late-life depression is associated with more brain atrophy and more white matter lesions, which was mainly driven by antidepressant use.

  15. Automatic brain caudate nuclei segmentation and classification in diagnostic of Attention-Deficit/Hyperactivity Disorder.

    PubMed

    Igual, Laura; Soliva, Joan Carles; Escalera, Sergio; Gimeno, Roger; Vilarroya, Oscar; Radeva, Petia

    2012-12-01

    We present a fully automatic diagnostic imaging test for Attention-Deficit/Hyperactivity Disorder diagnosis assistance based on previously found evidences of caudate nucleus volumetric abnormalities. The proposed method consists of different steps: a new automatic method for external and internal segmentation of caudate based on Machine Learning methodologies; the definition of a set of new volume relation features, 3D Dissociated Dipoles, used for caudate representation and classification. We separately validate the contributions using real data from a pediatric population and show precise internal caudate segmentation and discrimination power of the diagnostic test, showing significant performance improvements in comparison to other state-of-the-art methods.

  16. Basketball training increases striatum volume.

    PubMed

    Park, In Sung; Lee, Kea Joo; Han, Jong Woo; Lee, Nam Joon; Lee, Won Teak; Park, Kyung Ah; Rhyu, Im Joo

    2011-02-01

    The striatum is associated with the learning and retention of motor skills. Several studies have shown that motor learning induces neuronal changes in the striatum. We investigated whether macroscopic change in striatum volume occurs in a segment of the human population who learned basketball-related motor skills and practiced them throughout their entire athletic life. Three-dimensional magnetic resonance imaging volumetry was performed in basketball players and healthy controls, and striatum volumes were compared based on basketball proficiency, region and side. We identified morphological enlargement in the striatum of basketball players in comparison with controls. Our results suggest that continued practice and repetitive performance of basketball-related motor skills may induce plastic structural changes in the human striatum.

  17. Impact Study on Driving by Special Populations. Final Report. Volume II: A Guide for the Evaluation of Handicapped Drivers.

    ERIC Educational Resources Information Center

    Brainin, Paul A.; And Others

    The second of a two-volume report on motor vehicle driving by handicapped persons presents an approach to the evaluation of drivers with 20 specific )edical problems. The guide provides information on symptoms, treatment, guidelines for determining risk levels (risk increasing and risk moderating factors), questions for the applicant, and…

  18. Impact Study on Driving by Special Populations. Final Report, Volume I: Conduct of the Project and State of the Art.

    ERIC Educational Resources Information Center

    Brainin, Paul A.; And Others

    The first of a two-volume report on motor vehicle driving by handicapped persons focuses on driving behavior for 19 types of handicapping conditions. Information is detailed regarding driver education and assessment materials, present state laws regarding licensing, relevant medical opinion regarding licensing and examination, complicating factors…

  19. Total and Regional Brain Volumes in a Population-Based Normative Sample from 4 to 18 Years: The NIH MRI Study of Normal Brain Development

    PubMed Central

    2012-01-01

    Using a population-based sampling strategy, the National Institutes of Health (NIH) Magnetic Resonance Imaging Study of Normal Brain Development compiled a longitudinal normative reference database of neuroimaging and correlated clinical/behavioral data from a demographically representative sample of healthy children and adolescents aged newborn through early adulthood. The present paper reports brain volume data for 325 children, ages 4.5–18 years, from the first cross-sectional time point. Measures included volumes of whole-brain gray matter (GM) and white matter (WM), left and right lateral ventricles, frontal, temporal, parietal and occipital lobe GM and WM, subcortical GM (thalamus, caudate, putamen, and globus pallidus), cerebellum, and brainstem. Associations with cross-sectional age, sex, family income, parental education, and body mass index (BMI) were evaluated. Key observations are: 1) age-related decreases in lobar GM most prominent in parietal and occipital cortex; 2) age-related increases in lobar WM, greatest in occipital, followed by the temporal lobe; 3) age-related trajectories predominantly curvilinear in females, but linear in males; and 4) small systematic associations of brain tissue volumes with BMI but not with IQ, family income, or parental education. These findings constitute a normative reference on regional brain volumes in children and adolescents. PMID:21613470

  20. Fully automatized renal parenchyma volumetry using a support vector machine based recognition system for subject-specific probability map generation in native MR volume data

    NASA Astrophysics Data System (ADS)

    Gloger, Oliver; Tönnies, Klaus; Mensel, Birger; Völzke, Henry

    2015-11-01

    In epidemiological studies as well as in clinical practice the amount of produced medical image data strongly increased in the last decade. In this context organ segmentation in MR volume data gained increasing attention for medical applications. Especially in large-scale population-based studies organ volumetry is highly relevant requiring exact organ segmentation. Since manual segmentation is time-consuming and prone to reader variability, large-scale studies need automatized methods to perform organ segmentation. Fully automatic organ segmentation in native MR image data has proven to be a very challenging task. Imaging artifacts as well as inter- and intrasubject MR-intensity differences complicate the application of supervised learning strategies. Thus, we propose a modularized framework of a two-stepped probabilistic approach that generates subject-specific probability maps for renal parenchyma tissue, which are refined subsequently by using several, extended segmentation strategies. We present a three class-based support vector machine recognition system that incorporates Fourier descriptors as shape features to recognize and segment characteristic parenchyma parts. Probabilistic methods use the segmented characteristic parenchyma parts to generate high quality subject-specific parenchyma probability maps. Several refinement strategies including a final shape-based 3D level set segmentation technique are used in subsequent processing modules to segment renal parenchyma. Furthermore, our framework recognizes and excludes renal cysts from parenchymal volume, which is important to analyze renal functions. Volume errors and Dice coefficients show that our presented framework outperforms existing approaches.

  1. Projection models for health-effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume I. Introduction to the SPAHR demographic model for health risk

    SciTech Connect

    Collins, J.J.; Lundy, R.T.; Grahn, D.; Ginevan, M.E.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projections. The model extends several health risk projection models by making realistic assumptions about the population at risk, and thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of response, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, number of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projections are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. The first volume presents the theory behind the SPAHR health risk projection model and several applications of the model to actual pollution episodes. The elements required for an effective health risk projection model are specified, and the models that have been used to date in health risk projections are outlined. These are compared with the demographic model, whose formulation is described in detail. Examples of the application of air pollution and radiation dose-response functions are included in order to demonstrate the estimation of future mortality and morbidity levels and the range of variation in excess deaths that occurs when populations structure is changed.

  2. A comparison study of atlas-based 3D cardiac MRI segmentation: global versus global and local transformations

    NASA Astrophysics Data System (ADS)

    Daryanani, Aditya; Dangi, Shusil; Ben-Zikri, Yehuda Kfir; Linte, Cristian A.

    2016-03-01

    Magnetic Resonance Imaging (MRI) is a standard-of-care imaging modality for cardiac function assessment and guidance of cardiac interventions thanks to its high image quality and lack of exposure to ionizing radiation. Cardiac health parameters such as left ventricular volume, ejection fraction, myocardial mass, thickness, and strain can be assessed by segmenting the heart from cardiac MRI images. Furthermore, the segmented pre-operative anatomical heart models can be used to precisely identify regions of interest to be treated during minimally invasive therapy. Hence, the use of accurate and computationally efficient segmentation techniques is critical, especially for intra-procedural guidance applications that rely on the peri-operative segmentation of subject-specific datasets without delaying the procedure workflow. Atlas-based segmentation incorporates prior knowledge of the anatomy of interest from expertly annotated image datasets. Typically, the ground truth atlas label is propagated to a test image using a combination of global and local registration. The high computational cost of non-rigid registration motivated us to obtain an initial segmentation using global transformations based on an atlas of the left ventricle from a population of patient MRI images and refine it using well developed technique based on graph cuts. Here we quantitatively compare the segmentations obtained from the global and global plus local atlases and refined using graph cut-based techniques with the expert segmentations according to several similarity metrics, including Dice correlation coefficient, Jaccard coefficient, Hausdorff distance, and Mean absolute distance error.

  3. Small-volume chylous ascites after laparoscopic radical gastrectomy for gastric cancer: Results from a large population-based sample

    PubMed Central

    Lu, Jun; Wei, Zhen-Quan; Huang, Chang-Ming; Zheng, Chao-Hui; Li, Ping; Xie, Jian-Wei; Wang, Jia-Bin; Lin, Jian-Xian; Chen, Qi-Yue; Cao, Long-Long; Lin, Mi

    2015-01-01

    AIM: To report the incidence and potential risk factors of small-volume chylous ascites (SVCA) following laparoscopic radical gastrectomy (LAG). METHODS: A total of 1366 consecutive gastric cancer patients who underwent LAG from January 2008 to June 2011 were enrolled in this study. We analyzed the patients based on the presence or absence of SVCA. RESULTS: SVCA was detected in 57 (4.17%) patients, as determined by the small-volume drainage (range, 30-100 mL/24 h) of triglyceride-rich fluid. Both univariate and multivariate analyses revealed that the total number of resected lymph nodes (LNs), No. 8 or No. 9 LN metastasis and N stage were independent risk factors for SVCA following LAG (P < 0.05). Regarding hospital stay, there was a significant difference between the groups with and without SVCA (P < 0.001). The 3-year disease-free and overall survival rates of the patients with SVCA were 47.4% and 56.1%, respectively, which were similar to those of the patients without SVCA (P > 0.05). CONCLUSION: SVCA following LAG developed significantly more frequently in the patients with ≥ 32 harvested LNs, ≥ 3 metastatic LNs, or No. 8 or No. 9 LN metastasis. SVCA, which was successfully treated with conservative management, was associated with a prolonged hospital stay but was not associated with the prognosis. PMID:25741151

  4. Seismic volumetric flattening and segmentation

    NASA Astrophysics Data System (ADS)

    Lomask, Jesse

    Two novel algorithms provide seismic interpretation solutions that use the full dimensionality of the data. The first is volumetric flattening and the second is image segmentation for tracking salt boundaries. Volumetric flattening is an efficient full-volume automatic dense-picking method applied to seismic data. First local dips (step-outs) are calculated over the entire seismic volume. The dips are then resolved into time shifts (or depth shifts) in a least-squares sense. To handle faults (discontinuous reflections), I apply a weighted inversion scheme. Additional information is incorporated in this flattening algorithm as geological constraints. The method is tested successfully on both synthetic and field data sets of varying degrees of complexity including salt piercements, angular unconformities, and laterally limited faults. The second full-volume interpretation method uses normalized cuts image segmentation to track salt interfaces. I apply a modified version of the normalized cuts image segmentation (NCIS) method to partition seismic images along salt interfaces. The method is capable of tracking interfaces that are not continuous, where conventional horizon tracking algorithms may fail. This method partitions the seismic image into two groups. One group is inside the salt body and the other is outside. Where the two groups meet is the salt boundary. By imposing bounds and by distributing the algorithm on a parallel cluster, I significantly increase efficiency and robustness. This method is demonstrated to be effective on both 2D and 3D seismic data sets.

  5. Integrated segmentation of cellular structures

    NASA Astrophysics Data System (ADS)

    Ajemba, Peter; Al-Kofahi, Yousef; Scott, Richard; Donovan, Michael; Fernandez, Gerardo

    2011-03-01

    Automatic segmentation of cellular structures is an essential step in image cytology and histology. Despite substantial progress, better automation and improvements in accuracy and adaptability to novel applications are needed. In applications utilizing multi-channel immuno-fluorescence images, challenges include misclassification of epithelial and stromal nuclei, irregular nuclei and cytoplasm boundaries, and over and under-segmentation of clustered nuclei. Variations in image acquisition conditions and artifacts from nuclei and cytoplasm images often confound existing algorithms in practice. In this paper, we present a robust and accurate algorithm for jointly segmenting cell nuclei and cytoplasm using a combination of ideas to reduce the aforementioned problems. First, an adaptive process that includes top-hat filtering, Eigenvalues-of-Hessian blob detection and distance transforms is used to estimate the inverse illumination field and correct for intensity non-uniformity in the nuclei channel. Next, a minimum-error-thresholding based binarization process and seed-detection combining Laplacian-of-Gaussian filtering constrained by a distance-map-based scale selection is used to identify candidate seeds for nuclei segmentation. The initial segmentation using a local maximum clustering algorithm is refined using a minimum-error-thresholding technique. Final refinements include an artifact removal process specifically targeted at lumens and other problematic structures and a systemic decision process to reclassify nuclei objects near the cytoplasm boundary as epithelial or stromal. Segmentation results were evaluated using 48 realistic phantom images with known ground-truth. The overall segmentation accuracy exceeds 94%. The algorithm was further tested on 981 images of actual prostate cancer tissue. The artifact removal process worked in 90% of cases. The algorithm has now been deployed in a high-volume histology analysis application.

  6. The Alterations of Cortical Volume, Thickness, Surface, and Density in the Intermediate Sporadic Parkinson's Disease from the Han Population of Mainland China

    PubMed Central

    Deng, Xia; Zhou, Meihong; Tang, Chunyan; Zhang, Jie; Zhu, Lei; Xie, Zunchun; Gong, Honghan; Xiao, Xiangzuo; Xu, Renshi

    2016-01-01

    Many symptoms of sporadic Parkinson's disease (sPD) can't be completely explained by the lesion of simple typical extrapyramidal circuit between striatum and substantia nigra. Therefore, we investigated the alteration of cortical volume, thickness, surface, and density in the intermediate sPD from the Han population of Mainland China in order to find the new pathological brain regions associated with the complex clinical manifestations of sPD. The cortical volume, thickness, surface and density were examined using the voxel-based cortical morphometry and corticometry on magnetic resonance image (MRI) in 67 intermediate sPD and 35 controls, the multiple adjusted comparisons analysis of all MRI data were employed to assess the relationships between the cortical morphometric alteration in the specific brain regions and sPD. Results showed that a significantly shrunk volume, thinned thickness and enlarged or reduced surface of cortex in some specific brain regions were closely associated with sPD, but all cortical densities were not different. The majority of morphometric alteration of hemisphere cortex was symmetric, but that in the left hemisphere was more significant. The cortical morphometric alterations in the frontal, temporal, parietal, occipital and limbic lobe, cerebellum, caudate, and thalamus were closely related to the clinical neural dysfunction (Clinical manifestations) of sPD. Our data indicated that the deficits of extensive brain regions involved in the development of sPD, resulted in a series of correspondent complex clinical manifestations in the disease. PMID:27536237

  7. The Alterations of Cortical Volume, Thickness, Surface, and Density in the Intermediate Sporadic Parkinson's Disease from the Han Population of Mainland China.

    PubMed

    Deng, Xia; Zhou, Meihong; Tang, Chunyan; Zhang, Jie; Zhu, Lei; Xie, Zunchun; Gong, Honghan; Xiao, Xiangzuo; Xu, Renshi

    2016-01-01

    Many symptoms of sporadic Parkinson's disease (sPD) can't be completely explained by the lesion of simple typical extrapyramidal circuit between striatum and substantia nigra. Therefore, we investigated the alteration of cortical volume, thickness, surface, and density in the intermediate sPD from the Han population of Mainland China in order to find the new pathological brain regions associated with the complex clinical manifestations of sPD. The cortical volume, thickness, surface and density were examined using the voxel-based cortical morphometry and corticometry on magnetic resonance image (MRI) in 67 intermediate sPD and 35 controls, the multiple adjusted comparisons analysis of all MRI data were employed to assess the relationships between the cortical morphometric alteration in the specific brain regions and sPD. Results showed that a significantly shrunk volume, thinned thickness and enlarged or reduced surface of cortex in some specific brain regions were closely associated with sPD, but all cortical densities were not different. The majority of morphometric alteration of hemisphere cortex was symmetric, but that in the left hemisphere was more significant. The cortical morphometric alterations in the frontal, temporal, parietal, occipital and limbic lobe, cerebellum, caudate, and thalamus were closely related to the clinical neural dysfunction (Clinical manifestations) of sPD. Our data indicated that the deficits of extensive brain regions involved in the development of sPD, resulted in a series of correspondent complex clinical manifestations in the disease. PMID:27536237

  8. Quantifying the distribution of inhalation exposure in human populations: distribution of minute volumes in adults and children.

    PubMed Central

    Beals, J A; Funk, L M; Fountain, R; Sedman, R

    1996-01-01

    Assessments of inhalation exposure to environmental agents necessitate quantitative estimates of pulmonary ventilation rates. Estimating a range of exposures in a given population requires an understanding of the variability of ventilation rates in the population. Distributions of ventilation rates (Ve) were described based on the results of a large study where Ve were measured while subjects performed a variety of physical tasks. Three distinct ventilation levels were identified using cluster analyses of the mean Ve and then various activities were assigned to the three levels using a k-means procedure. Separate distributions were identified for the three Ve levels for adult males, adult females, and children. The variability of Ve was consistent with a lognormal distribution for all groups. An aggregate daily inhalation rate can be estimated based on the distributions of Ve. Images Figure 1. Figure 1. Figure 1. PMID:8899377

  9. Compensatory mechanisms in fish populations: Literature reviews: Volume 1, Critical evaluation of case histories of fish populations experiencing chronic exploitation or impact: Final report

    SciTech Connect

    Saila, S.B.; Chen, X.; Erzini, K.; Martin, B.

    1987-05-01

    This study includes case histories of certain fish species which are experiencing chronic perturbations and related literature pertaining to compensation processes. ''Compensation'' has been defined as the ability of fish to offset the population reduction caused by natural or man-induced stresses. Certain compensation methods are widely accepted, and include cannibalism, competition, disease, growth and predation, among others. These compensation methods are examined in relation to each fish species included in the study. Stock-recruit relationships and empirical observations of changes in growth and mortality have been the focus of much of the background on compensation. One of the conclusions drawn from this study is that a significant amount of recruitment variability exists and can be attributed to environmental (rather than compensatory) factors. The stock-recruitment problem appears to be the most significant scientific problem related to compensation in the types of fish included in this study. Results of the most recent studies of the American shad support this theory. Life histories, breeding biology and other pertinent data relating to each species included in the study will be found in the appendices.

  10. The effects of designation and volume of neonatal care on mortality and morbidity outcomes of very preterm infants in England: retrospective population-based cohort study

    PubMed Central

    Watson, S I; Arulampalam, W; Petrou, S; Marlow, N; Morgan, A S; Draper, E S; Santhakumaran, S; Modi, N

    2014-01-01

    Objective To examine the effects of designation and volume of neonatal care at the hospital of birth on mortality and morbidity outcomes in very preterm infants in a managed clinical network setting. Design A retrospective, population-based analysis of operational clinical data using adjusted logistic regression and instrumental variables (IV) analyses. Setting 165 National Health Service neonatal units in England contributing data to the National Neonatal Research Database at the Neonatal Data Analysis Unit and participating in the Neonatal Economic, Staffing and Clinical Outcomes Project. Participants 20 554 infants born at <33 weeks completed gestation (17 995 born at 27–32 weeks; 2559 born at <27 weeks), admitted to neonatal care and either discharged or died, over the period 1 January 2009–31 December 2011. Intervention Tertiary designation or high-volume neonatal care at the hospital of birth. Outcomes Neonatal mortality, any in-hospital mortality, surgery for necrotising enterocolitis, surgery for retinopathy of prematurity, bronchopulmonary dysplasia and postmenstrual age at discharge. Results Infants born at <33 weeks gestation and admitted to a high-volume neonatal unit at the hospital of birth were at reduced odds of neonatal mortality (IV regression odds ratio (OR) 0.70, 95% CI 0.53 to 0.92) and any in-hospital mortality (IV regression OR 0.68, 95% CI 0.54 to 0.85). The effect of volume on any in-hospital mortality was most acute among infants born at <27 weeks gestation (IV regression OR 0.51, 95% CI 0.33 to 0.79). A negative association between tertiary-level unit designation and mortality was also observed with adjusted logistic regression for infants born at <27 weeks gestation. Conclusions High-volume neonatal care provided at the hospital of birth may protect against in-hospital mortality in very preterm infants. Future developments of neonatal services should promote delivery of very preterm infants at hospitals with high-volume

  11. Exposure factors handbook. Volume 2 of 3. Food ingestion factors. Preliminary review draft

    SciTech Connect

    Wood, P.; Phillips, L.; Adenuga, A.; Koontz, M.; Rector, H.

    1996-08-01

    The document provides a summary of the available statistical data on various factors used in assessing human exposure. Volume II, Food Ingestion, provides data for consumption of fruits and vegetables, fish, meats and dairy products, homegrown foods, and breast milk. The basic equations using these parameters to calculate exposure levels are also provided. Recommended values are also provided for various segments of the population who may be have characteristics different from the general population.

  12. Consequences of Changing U.S. Population: Population Movement and Planning; Hearings before the Select Committee on Population, House of Representatives, Ninety-Fifth Congress, Second Session. Volume III.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Select Committee on Population.

    This report of congressional hearings on population movement and its implications for future planning focuses on the relative growth and decline in population within different geographic areas (both urban and rural) of the United States. Specific issues addressed include the effects these trends will have on school enrollments, family life,…

  13. Segmenting images analytically in shape space

    NASA Astrophysics Data System (ADS)

    Rathi, Yogesh; Dambreville, Samuel; Niethammer, Marc; Malcolm, James; Levitt, James; Shenton, Martha E.; Tannenbaum, Allen

    2008-03-01

    This paper presents a novel analytic technique to perform shape-driven segmentation. In our approach, shapes are represented using binary maps, and linear PCA is utilized to provide shape priors for segmentation. Intensity based probability distributions are then employed to convert a given test volume into a binary map representation, and a novel energy functional is proposed whose minimum can be analytically computed to obtain the desired segmentation in the shape space. We compare the proposed method with the log-likelihood based energy to elucidate some key differences. Our algorithm is applied to the segmentation of brain caudate nucleus and hippocampus from MRI data, which is of interest in the study of schizophrenia and Alzheimer's disease. Our validation (we compute the Hausdorff distance and the DICE coefficient between the automatic segmentation and ground-truth) shows that the proposed algorithm is very fast, requires no initialization and outperforms the log-likelihood based energy.

  14. Automatic characterization and segmentation of human skin using three-dimensional optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Hori, Yasuaki; Yasuno, Yoshiaki; Sakai, Shingo; Matsumoto, Masayuki; Sugawara, Tomoko; Madjarova, Violeta; Yamanari, Masahiro; Makita, Shuichi; Yasui, Takeshi; Araki, Tsutomu; Itoh, Masahide; Yatagai, Toyohiko

    2006-03-01

    A set of fully automated algorithms that is specialized for analyzing a three-dimensional optical coherence tomography (OCT) volume of human skin is reported. The algorithm set first determines the skin surface of the OCT volume, and a depth-oriented algorithm provides the mean epidermal thickness, distribution map of the epidermis, and a segmented volume of the epidermis. Subsequently, an en face shadowgram is produced by an algorithm to visualize the infundibula in the skin with high contrast. The population and occupation ratio of the infundibula are provided by a histogram-based thresholding algorithm and a distance mapping algorithm. En face OCT slices at constant depths from the sample surface are extracted, and the histogram-based thresholding algorithm is again applied to these slices, yielding a three-dimensional segmented volume of the infundibula. The dermal attenuation coefficient is also calculated from the OCT volume in order to evaluate the skin texture. The algorithm set examines swept-source OCT volumes of the skins of several volunteers, and the results show the high stability, portability and reproducibility of the algorithm.

  15. Segment alignment control system

    NASA Technical Reports Server (NTRS)

    Aubrun, JEAN-N.; Lorell, Ken R.

    1988-01-01

    The segmented primary mirror for the LDR will require a special segment alignment control system to precisely control the orientation of each of the segments so that the resulting composite reflector behaves like a monolith. The W.M. Keck Ten Meter Telescope will utilize a primary mirror made up of 36 actively controlled segments. Thus the primary mirror and its segment alignment control system are directly analogous to the LDR. The problems of controlling the segments in the face of disturbances and control/structures interaction, as analyzed for the TMT, are virtually identical to those for the LDR. The two systems are briefly compared.

  16. Sipunculans and segmentation

    PubMed Central

    Kristof, Alen; Brinkmann, Nora

    2009-01-01

    Comparative molecular, developmental and morphogenetic analyses show that the three major segmented animal groups—Lophotrochozoa, Ecdysozoa and Vertebrata—use a wide range of ontogenetic pathways to establish metameric body organization. Even in the life history of a single specimen, different mechanisms may act on the level of gene expression, cell proliferation, tissue differentiation and organ system formation in individual segments. Accordingly, in some polychaete annelids the first three pairs of segmental peripheral neurons arise synchronously, while the metameric commissures of the ventral nervous system form in anterior-posterior progression. Contrary to traditional belief, loss of segmentation may have occurred more often than commonly assumed, as exemplified in the sipunculans, which show remnants of segmentation in larval stages but are unsegmented as adults. The developmental plasticity and potential evolutionary lability of segmentation nourishes the controversy of a segmented bilaterian ancestor versus multiple independent evolution of segmentation in respective metazoan lineages. PMID:19513266

  17. Station Tour: Russian Segment

    NASA Video Gallery

    Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1...

  18. Projection models for health-effects assessment in populations exposed to radioactive and nonradioactive pollutants. Volume III. SPAHR interactive package guide

    SciTech Connect

    Collins, J.J.

    1982-09-01

    The Simulation Package for the Analysis of Health Risk (SPAHR) is a computer software package based upon a demographic model for health risk projectons. The model extends several health risk projection models by making realistic assumptions about the population at risk, adn thus represents a distinct improvement over previous models. Complete documentation for use of SPAHR is contained in this five-volume publication. The demographic model in SPAHR estimates population response to environmental toxic exposures. Latency of response, changing dose level over time, competing risks from other causes of death, and population structure can be incorporated into SPAHR to project health risks. Risks are measured by morbid years, number of deaths, and loss of life expectancy. Comparisons of estimates of excess deaths demonstrate that previous health risk projection models may have underestimated excess deaths by a factor of from 2 to 10, depending on the pollutant and the exposure scenario. The software supporting the use of the demographic model is designed to be user oriented. Complex risk projections are made by responding to a series of prompts generated by the package. The flexibility and ease of use of SPAHR make it an important contribution to existing models and software packages. This manual outlines the use of the interactive capabilities of SPAHR. SPAHR is an integrated system of computer programs designed for simulating numerous health risk scenarios using the techniques of demographic modeling. This system of computer programs has been designed to be very flexible so as to allow the user to simulate a large variety of scenarios. It provides the user with an integrated package for projecting the impacts on human health of exposure to various hazards, particularly those resulting from the effluents related to energy production.

  19. Hand grip strength is associated with forced expiratory volume in 1 second among subjects with COPD: report from a population-based cohort study

    PubMed Central

    Strandkvist, Viktor Johansson; Backman, Helena; Röding, Jenny; Stridsman, Caroline; Lindberg, Anne

    2016-01-01

    Background Cardiovascular diseases and skeletal muscle dysfunction are common comorbidities in COPD. Hand grip strength (HGS) is related to general muscle strength and is associated with cardiovascular disease and all-cause mortality, while the results from small selected COPD populations are contradictory. The aim of this population-based study was to compare HGS among the subjects with and without COPD, to evaluate HGS in relation to COPD severity, and to evaluate the impact of heart disease. Subjects and methods Data were collected from the Obstructive Lung disease in Northern Sweden COPD study, where the subjects with and without COPD have been invited to annual examinations since 2005. In 2009–2010, 441 subjects with COPD (postbronchodilator forced expiratory volume in 1 second [FEV1]/vital capacity <0.70) and 570 without COPD participated in structured interviews, spirometry, and measurements of HGS. Results The mean HGS was similar when comparing subjects with and without COPD, but those with heart disease had lower HGS than those without. When compared by Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, the subjects with GOLD 3–4 had lower HGS than those without COPD in both sexes (females 21.4 kg vs 26.9 kg, P=0.010; males 41.5 kg vs 46.3 kg, P=0.038), and the difference persisted also when adjusted for confounders. Among the subjects with COPD, HGS was associated with FEV1% of predicted value but not heart disease when adjusted for height, age, sex, and smoking habits, and the pattern was similar among males and females. Conclusion In this population-based study, the subjects with GOLD 3–4 had lower HGS than the subjects without COPD. Among those with COPD, HGS was associated with FEV1% of predicted value but not heart disease, and the pattern was similar in both sexes. PMID:27785009

  20. Monitoring fish distributions along electrofishing segments

    USGS Publications Warehouse

    Miranda, Leandro E.

    2014-01-01

    Electrofishing is widely used to monitor fish species composition and relative abundance in streams and lakes. According to standard protocols, multiple segments are selected in a body of water to monitor population relative abundance as the ratio of total catch to total sampling effort. The standard protocol provides an assessment of fish distribution at a macrohabitat scale among segments, but not within segments. An ancillary protocol was developed for assessing fish distribution at a finer scale within electrofishing segments. The ancillary protocol was used to estimate spacing, dispersion, and association of two species along shore segments in two local reservoirs. The added information provided by the ancillary protocol may be useful for assessing fish distribution relative to fish of the same species, to fish of different species, and to environmental or habitat characteristics.

  1. What is a segment?

    PubMed

    Hannibal, Roberta L; Patel, Nipam H

    2013-12-17

    Animals have been described as segmented for more than 2,000 years, yet a precise definition of segmentation remains elusive. Here we give the history of the definition of segmentation, followed by a discussion on current controversies in defining a segment. While there is a general consensus that segmentation involves the repetition of units along the anterior-posterior (a-p) axis, long-running debates exist over whether a segment can be composed of only one tissue layer, whether the most anterior region of the arthropod head is considered segmented, and whether and how the vertebrate head is segmented. Additionally, we discuss whether a segment can be composed of a single cell in a column of cells, or a single row of cells within a grid of cells. We suggest that 'segmentation' be used in its more general sense, the repetition of units with a-p polarity along the a-p axis, to prevent artificial classification of animals. We further suggest that this general definition be combined with an exact description of what is being studied, as well as a clearly stated hypothesis concerning the specific nature of the potential homology of structures. These suggestions should facilitate dialogue among scientists who study vastly differing segmental structures.

  2. Duplication of coding segments in genetic programming

    SciTech Connect

    Haynes, T.

    1996-12-31

    Research into the utility of non-coding segments, or introns, in genetic-based encodings has shown that they expedite the evolution of solutions in domains by protecting building blocks against destructive crossover. We consider a genetic programming system where non-coding segments can be removed, and the resultant chromosomes returned into the population. This parsimonious repair leads to premature convergence, since as we remove the naturally occurring non-coding segments, we strip away their protective backup feature. We then duplicate the coding segments in the repaired chromosomes, and place the modified chromosomes into the population. The duplication method significantly improves the learning rate in the domain we have considered. We also show that this method can be applied to other domains.

  3. Automated Tumor Volumetry Using Computer-Aided Image Segmentation

    PubMed Central

    Bilello, Michel; Sadaghiani, Mohammed Salehi; Akbari, Hamed; Atthiah, Mark A.; Ali, Zarina S.; Da, Xiao; Zhan, Yiqang; O'Rourke, Donald; Grady, Sean M.; Davatzikos, Christos

    2015-01-01

    Rationale and Objectives Accurate segmentation of brain tumors, and quantification of tumor volume, is important for diagnosis, monitoring, and planning therapeutic intervention. Manual segmentation is not widely used because of time constraints. Previous efforts have mainly produced methods that are tailored to a particular type of tumor or acquisition protocol and have mostly failed to produce a method that functions on different tumor types and is robust to changes in scanning parameters, resolution, and image quality, thereby limiting their clinical value. Herein, we present a semiautomatic method for tumor segmentation that is fast, accurate, and robust to a wide variation in image quality and resolution. Materials and Methods A semiautomatic segmentation method based on the geodesic distance transform was developed and validated by using it to segment 54 brain tumors. Glioblastomas, meningiomas, and brain metastases were segmented. Qualitative validation was based on physician ratings provided by three clinical experts. Quantitative validation was based on comparing semiautomatic and manual segmentations. Results Tumor segmentations obtained using manual and automatic methods were compared quantitatively using the Dice measure of overlap. Subjective evaluation was performed by having human experts rate the computerized segmentations on a 0–5 rating scale where 5 indicated perfect segmentation. Conclusions The proposed method addresses a significant, unmet need in the field of neuro-oncology. Specifically, this method enables clinicians to obtain accurate and reproducible tumor volumes without the need for manual segmentation. PMID:25770633

  4. Segmental lichen planus pigmentosus: An unusual presentation

    PubMed Central

    Kumar, Y Hari Kishan; Babu, Anagha Ramesh

    2014-01-01

    Lichen planus pigmentosus (LPP) is a distinct clinical entity commonly encountered in the Indian population. It is considered a variant of lichen planus (LP). A 40-year-old male presented with asymptomatic hyperpigmented macules in a segmental distribution since 10 years that were clinically and histopathologically suggestive of LPP. We propose the terminology “segmental lichen planus pigmentosus” and report this unusual presentation. PMID:24860750

  5. Automatic segmentation of breast MR images through a Markov random field statistical model.

    PubMed

    Ribes, S; Didierlaurent, D; Decoster, N; Gonneau, E; Risser, L; Feillel, V; Caselles, O

    2014-10-01

    An algorithm dedicated to automatic segmentation of breast magnetic resonance images is presented in this paper. Our approach is based on a pipeline that includes a denoising step and statistical segmentation. The noise removal preprocessing relies on an anisotropic diffusion scheme, whereas the statistical segmentation is conducted through a Markov random field model. The continuous updating of all parameters governing the diffusion process enables automatic denoising, and the partial volume effect is also addressed during the labeling step. To assess the relevance, the Jaccard similarity coefficient was computed. Experiments were conducted on synthetic data and breast magnetic resonance images extracted from a high-risk population. The relevance of the approach for the dataset is highlighted, and we demonstrate accuracy superior to that of traditional clustering algorithms. The results emphasize the benefits of both denoising guided by input data and the inclusion of spatial dependency through a Markov random field. For example, the Jaccard coefficient for the clinical data was increased by 114%, 109%, and 140% with respect to a K-means algorithm and, respectively, for the adipose, glandular and muscle and skin components. Moreover, the agreement between the manual segmentations provided by an experienced radiologist and the automatic segmentations performed with this algorithm was good, with Jaccard coefficients equal to 0.769, 0.756, and 0.694 for the above-mentioned classes.

  6. Segmentation of inversion recovery MR images using neural networks: a study on aging

    NASA Astrophysics Data System (ADS)

    Glass, John O.; Reddick, Wilburn E.; Yo, Virginia S.; Steen, R. G.

    1998-06-01

    Clinicians have long desired early detection of neurological abnormality for treatment of brain malignancies. In attempts to address this concern, there are numerous reports publishing normative databases of age-related changes of the brain in healthy controls, many using magnetic resonance imaging (MRI). However, most of the method used to access tissue volumes were subject to observer variability. We developed a Kohonen self-organizing map to automatically segment MR images for reproducible and accurate identification of tissues. The developed method was applied to quantitatively assess subtle volume differences in normal controls due to maturational and degenerative changes. The volumes calculated in the test population of 73 controls agreed with current hypothesizes concerning age-related changes of the brain as determined by linear regression analysis of segmented tissue to age. Percent gray matter and percent white matter, as well as the ratio of gray matter to white matter were all found to be significantly correlated with age. Percent gray matter and the ratio of gray matter to white matter were inversely proportional to age while percent white matter was directly proportional to age. These results suggest the utility of the developed segmentation technique, as well as the clinical application it may hold.

  7. Self-Paced Physics, Segment 18.

    ERIC Educational Resources Information Center

    New York Inst. of Tech., Old Westbury.

    Eighty-seven problems are included in this volume which is arranged to match study segments 2 through 14. The subject matter is related to projectiles, simple harmonic motion, kinetic friction, multiple pulley arrangements, motion on inclined planes, circular motion, potential energy, kinetic energy, center of mass, Newton's laws, elastic and…

  8. What is a segment?

    PubMed Central

    2013-01-01

    Animals have been described as segmented for more than 2,000 years, yet a precise definition of segmentation remains elusive. Here we give the history of the definition of segmentation, followed by a discussion on current controversies in defining a segment. While there is a general consensus that segmentation involves the repetition of units along the anterior-posterior (a-p) axis, long-running debates exist over whether a segment can be composed of only one tissue layer, whether the most anterior region of the arthropod head is considered segmented, and whether and how the vertebrate head is segmented. Additionally, we discuss whether a segment can be composed of a single cell in a column of cells, or a single row of cells within a grid of cells. We suggest that ‘segmentation’ be used in its more general sense, the repetition of units with a-p polarity along the a-p axis, to prevent artificial classification of animals. We further suggest that this general definition be combined with an exact description of what is being studied, as well as a clearly stated hypothesis concerning the specific nature of the potential homology of structures. These suggestions should facilitate dialogue among scientists who study vastly differing segmental structures. PMID:24345042

  9. The Combined Effects of Hospital and Surgeon Volume on Short-Term Survival after Hepatic Resection in a Population-Based Study

    PubMed Central

    Chang, Chun-Ming; Yin, Wen-Yao; Wei, Chang-Kao; Lee, Cheng-Hung; Lee, Ching-Chih

    2014-01-01

    Background The influence of different hospital and surgeon volumes on short-term survival after hepatic resection is not clearly clarified. By taking the known prognostic factors into account, the purpose of this study is to assess the combined effects of hospital and surgeon volume on short-term survival after hepatic resection. Methods 13,159 patients who underwent hepatic resection between 2002 and 2006 were identified in the Taiwan National Health Insurance Research Database. Data were extracted from it and short-term survivals were confirmed through 2006. The Cox proportional hazards model was used to assess the relationship between survival and different hospital, surgeon volume and caseload combinations. Results High-volume surgeons in high-volume hospitals had the highest short-term survivals, following by high-volume surgeons in low-volume hospitals, low-volume surgeons in high-volume hospitals and low-volume surgeons in low-volume hospitals. Based on Cox proportional hazard models, although high-volume hospitals and surgeons both showed significant lower risks of short-term mortality at hospital and surgeon level analysis, after combining hospital and surgeon volume into account, high-volume surgeons in high-volume hospitals had significantly better outcomes; the hazard ratio of other three caseload combinations ranging from 1.66 to 2.08 (p<0.001) in 3-month mortality, and 1.28 to 1.58 (p<0.01) in 1-year mortality. Conclusions The combined effects of hospital and surgeon volume influenced the short-term survival after hepatic resection largely. After adjusting for the prognostic factors in the case mix, high-volume surgeons in high-volume hospitals had better short-term survivals. Centralization of hepatic resection to few surgeons and hospitals might improve patients’ prognosis. PMID:24466102

  10. Population-based estimation of renal function in healthy young Indian adults based on body mass index and sex correlating renal volume, serum creatinine, and cystatin C

    PubMed Central

    Rajagopalan, Prashanth; Abraham, Georgi; Reddy, Yuvaram NV; Lakshmanasami, Ravivarman; Prakash, ML; Reddy, Yogesh NV

    2016-01-01

    This population-based prospective study was undertaken in Mahatma Gandhi Medical College to estimate the renal function in young healthy Indian adults. A young healthy heterogeneous Indian cohort comprising 978 individuals, predominantly medical students, was assessed by a detailed questionnaire, and variables such as height, weight, body mass index (BMI), birth weight, and blood pressure were documented. Laboratory investigations included serum creatinine, serum cystatin C, blood sugar, urine protein, and imaging of the kidneys with ultrasound. The mean age of the cohort was 25±6 years, comprising 672 males and 306 females. The estimated glomerular filtration rates (eGFRs) by the Cockcroft–Gault formula for BMI <18.5 kg/m2, 18.5–24.99 kg/m2, 25–29.99 kg/m2, and ≥30 kg/m2 were 71.29±10.45 mL/min, 86.38±13.46 mL/min, 98.88±15.29 mL/min, and 109.13±21.57 mL/min, respectively; the eGFRs using cystatin C for the four groups of BMI were 84.53±18.14 mL/min, 84.01±40.11 mL/min, 79.18±13.46 mL/min, and 77.30±10.90 mL/min, respectively. This study attempts to establish a normal range of serum creatinine and cystatin C values for the Indian population and shows that in young healthy Indian adults, eGFR and kidney volume vary by BMI and sex. PMID:27729810

  11. Automatic Contrail Detection and Segmentation

    NASA Technical Reports Server (NTRS)

    Weiss, John M.; Christopher, Sundar A.; Welch, Ronald M.

    1998-01-01

    Automatic contrail detection is of major importance in the study of the atmospheric effects of aviation. Due to the large volume of satellite imagery, selecting contrail images for study by hand is impractical and highly subject to human error. It is far better to have a system in place that will automatically evaluate an image to determine 1) whether it contains contrails and 2) where the contrails are located. Preliminary studies indicate that it is possible to automatically detect and locate contrails in Advanced Very High Resolution Radiometer (AVHRR) imagery with a high degree of confidence. Once contrails have been identified and localized in a satellite image, it is useful to segment the image into contrail versus noncontrail pixels. The ability to partition image pixels makes it possible to determine the optical properties of contrails, including optical thickness and particle size. In this paper, we describe a new technique for segmenting satellite images containing contrails. This method has good potential for creating a contrail climatology in an automated fashion. The majority of contrails are detected, rejecting clutter in the image, even cirrus streaks. Long, thin contrails are most easily detected. However, some contrails may be missed because they are curved, diffused over a large area, or present in short segments. Contrails average 2-3 km in width for the cases studied.

  12. Monitoring and Research on the Bi-State Distinct Population Segment of Greater Sage-Grouse (Centrocercus urophasianus) in the Pine Nut Mountains, California and Nevada—Study Progress Report, 2011−15

    USGS Publications Warehouse

    Coates, Peter S.; Andrle, Katie M.; Ziegler, Pilar T.; Casazza, Michael L.

    2016-09-29

    The Bi-State distinct population segment (DPS) of greater sage-grouse (Centrocercus urophasianus) that occurs along the Nevada–California border was proposed for listing as threatened under the Endangered Species Act (ESA) by the U.S. Fish and Wildlife Service (FWS) in October 2013. However, in April 2015, the FWS determined that the Bi-State DPS no longer required protection under the ESA and withdrew the proposed rule to list the Bi-State DPS (U.S. Fish and Wildlife Service, 2015). The Bi-State DPS occupies portions of Alpine, Mono, and Inyo Counties in California, and Douglas, Esmeralda, Lyon, Carson City, and Mineral Counties in Nevada. Unique threats facing this population include geographic isolation, expansion of single-leaf pinyon (Pinus monophylla) and Utah juniper (Juniperus osteosperma), anthropogenic activities, and recent changes in predator communities. Estimating population vital rates, identifying seasonal habitat, quantifying threats, and identifying movement patterns are important first steps in developing effective sage-grouse management and conservation plans. During 2011–15, we radio- and Global Positioning System (GPS)-marked (2012–14 only) 44, 47, 17, 9, and 3 sage-grouse, respectively, for a total of 120, in the Pine Nut Mountains Population Management Unit (PMU). No change in lek attendance was detected at Mill Canyon (maximum=18 males) between 2011 and 2012; however, 1 male was observed in 2014 and no males were observed in 2013 and 2015. Males were observed near Bald Mountain in 2013, making it the first year this lek was observed to be active during the study period. Males were observed at a new site in the Buckskin Range in 2014 during trapping efforts and again observed during surveys in 2015. Findings indicate that pinyon-juniper is avoided by sage-grouse during every life stage. Nesting females selected increased sagebrush cover, sagebrush height, and understory horizontal cover, and brood-rearing females selected similar areas

  13. Monitoring and research on the Bi-State Distinct Population Segment of greater sage-grouse (Centrocercus urophasianus) in the Pine Nut Mountains, California and Nevada—Study progress report, 2011–15

    USGS Publications Warehouse

    Coates, Peter S.; Andrle, Katie M.; Ziegler, Pilar T.; Casazza, Michael L.

    2016-09-29

    The Bi-State distinct population segment (DPS) of greater sage-grouse (Centrocercus urophasianus) that occurs along the Nevada–California border was proposed for listing as threatened under the Endangered Species Act (ESA) by the U.S. Fish and Wildlife Service (FWS) in October 2013. However, in April 2015, the FWS determined that the Bi-State DPS no longer required protection under the ESA and withdrew the proposed rule to list the Bi-State DPS (U.S. Fish and Wildlife Service, 2015). The Bi-State DPS occupies portions of Alpine, Mono, and Inyo Counties in California, and Douglas, Esmeralda, Lyon, Carson City, and Mineral Counties in Nevada. Unique threats facing this population include geographic isolation, expansion of single-leaf pinyon (Pinus monophylla) and Utah juniper (Juniperus osteosperma), anthropogenic activities, and recent changes in predator communities. Estimating population vital rates, identifying seasonal habitat, quantifying threats, and identifying movement patterns are important first steps in developing effective sage-grouse management and conservation plans. During 2011–15, we radio- and Global Positioning System (GPS)-marked (2012–14 only) 44, 47, 17, 9, and 3 sage-grouse, respectively, for a total of 120, in the Pine Nut Mountains Population Management Unit (PMU). No change in lek attendance was detected at Mill Canyon (maximum=18 males) between 2011 and 2012; however, 1 male was observed in 2014 and no males were observed in 2013 and 2015. Males were observed near Bald Mountain in 2013, making it the first year this lek was observed to be active during the study period. Males were observed at a new site in the Buckskin Range in 2014 during trapping efforts and again observed during surveys in 2015. Findings indicate that pinyon-juniper is avoided by sage-grouse during every life stage. Nesting females selected increased sagebrush cover, sagebrush height, and understory horizontal cover, and brood-rearing females selected similar areas

  14. Segmented Trough Reflector

    NASA Technical Reports Server (NTRS)

    Szmyd, W. R.

    1985-01-01

    Segmented troughlike reflector for solar cells approach concentration effectiveness of true parabolic reflector yet simpler and less expensive. Walls of segmented reflector composed of reflective aluminized membrane. Lengthwise guide wire applies tension to each wall, thereby dividing each into two separate planes. Planes tend to focus Sunlight on solar cells at center of trough between walls. Segmented walls provide higher Sunlight concentration ratios than do simple walls.

  15. Hybrid segmentation framework for 3D medical image analysis

    NASA Astrophysics Data System (ADS)

    Chen, Ting; Metaxas, Dimitri N.

    2003-05-01

    Medical image segmentation is the process that defines the region of interest in the image volume. Classical segmentation methods such as region-based methods and boundary-based methods cannot make full use of the information provided by the image. In this paper we proposed a general hybrid framework for 3D medical image segmentation purposes. In our approach we combine the Gibbs Prior model, and the deformable model. First, Gibbs Prior models are applied onto each slice in a 3D medical image volume and the segmentation results are combined to a 3D binary masks of the object. Then we create a deformable mesh based on this 3D binary mask. The deformable model will be lead to the edge features in the volume with the help of image derived external forces. The deformable model segmentation result can be used to update the parameters for Gibbs Prior models. These methods will then work recursively to reach a global segmentation solution. The hybrid segmentation framework has been applied to images with the objective of lung, heart, colon, jaw, tumor, and brain. The experimental data includes MRI (T1, T2, PD), CT, X-ray, Ultra-Sound images. High quality results are achieved with relatively efficient time cost. We also did validation work using expert manual segmentation as the ground truth. The result shows that the hybrid segmentation may have further clinical use.

  16. Impact assisted segmented cutterhead

    DOEpatents

    Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

    1992-01-01

    An impact assisted segmented cutterhead device is provided for cutting various surfaces from coal to granite. The device comprises a plurality of cutting bit segments deployed in side by side relationship to form a continuous cutting face and a plurality of impactors individually associated with respective cutting bit segments. An impactor rod of each impactor connects that impactor to the corresponding cutting bit segment. A plurality of shock mounts dampening the vibration from the associated impactor. Mounting brackets are used in mounting the cutterhead to a base machine.

  17. Indicators of Children's Well-Being: Conference Papers. Cross-Cutting Issues; Population, Family, and Neighborhood; Social Development and Problem Behaviors. Volume III. Special Report Series. Special Report Number 60c.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison. Inst. for Research on Poverty.

    Papers in this volume explore indicators of children's well-being in the following areas: cross-cutting issues; population, family, and neighborhood; and social development and problem behaviors. The first section includes: (1) "Potential and Problems in Developing Indicators on Child Well-Being from Administrative Data" (Robert M. Goerge); (2)…

  18. Hospital benefit segmentation.

    PubMed

    Finn, D W; Lamb, C W

    1986-12-01

    Market segmentation is an important topic to both health care practitioners and researchers. The authors explore the relative importance that health care consumers attach to various benefits available in a major metropolitan area hospital. The purposes of the study are to test, and provide data to illustrate, the efficacy of one approach to hospital benefit segmentation analysis.

  19. Vowel aperture and syllable segmentation in French.

    PubMed

    Goslin, Jeremy; Frauenfelder, Ulrich H

    2008-01-01

    The theories of Pulgram (1970) suggest that if the vowel of a French syllable is open then it will induce syllable segmentation responses that result in the syllable being closed, and vice versa. After the empirical verification that our target French-speaking population was capable of distinguishing between mid-vowel aperture, we examined the relationship between vowel and syllable aperture in two segmentation experiments. Initial findings from a metalinguistic repetition task supported the hypothesis, revealing significant segmentation differences due to vowel aperture across a range of bi-syllabic stimuli. These findings were also supported in an additional online experiment, in which a fragment detection task revealed a syllabic cross-over interaction due to vowel aperture. Evidence from these experiments suggest that multiple, independent cues are used in French syllable segmentation, including vowel aperture.

  20. Evaluation of ultra-low-volume insecticide dispensing systems for use in single-engined aircraft and their effectiveness against Aedes aegypti populations in South-East Asia*

    PubMed Central

    Kilpatrick, John W.; Tonn, Robert J.; Jatanasen, Sujarti

    1970-01-01

    An evaluation study of ultra-low-volume (ULV) spraying of insecticide from aircraft was carried out in Thailand, to determine if this technique could be used for the emergency control of Aedes aegypti, the major vector of haemorrhagic fever. A small, single-engined aircraft, a Cessna-180, was used in the trials and 2 types of spraying equipment were tested; both were found to be equally effective. The aircraft was fitted with 6 spraying nozzles and flew at an altitude of 150 feet (46 m) at a speed of 100 miles/h (161 km/h). The insecticide used was 95% technical grade malathion and swaths 75 feet wide (22.8 m) were laid down; the rate of application was 3 US fl oz/acre (219 ml/ha). Trials were made in 3 villages near Bangkok and it became apparent that a small aircraft could not produce the required even distribution of insecticide; the rate of application was therefore increased to 6 US fl oz/acre (438 ml/ha). This increased rate appeared to compensate for the narrow width of the swath and produced very satisfactory mortalities in caged mosquitos as well as in natural populations. The size and distribution of droplets was monitored by the use of oil-sensitive red dye cards which showed that there was a good penetration of insecticide into dwellings, etc. Trial results were evaluated by biting counts, bioassays of Aedes and Culex adults and larvae, Culex dips and ovitraps. Biossays indicated that the 6 US fl oz/acre rate of application was almost 100% effective in the open and produced satisfactory mortalities inside markets and dwellings. It was concluded that larger aircraft would be required to treat areas of more than 1000 acres (405 ha) and congested city areas but that the rate of application of insecticide could be considerably lower. Nevertheless, small aircraft can be useful in smaller and less congested areas. PMID:5309517

  1. Segmenting patients and physicians using preferences from discrete choice experiments.

    PubMed

    Deal, Ken

    2014-01-01

    People often form groups or segments that have similar interests and needs and seek similar benefits from health providers. Health organizations need to understand whether the same health treatments, prevention programs, services, and products should be applied to everyone in the relevant population or whether different treatments need to be provided to each of several segments that are relatively homogeneous internally but heterogeneous among segments. Our objective was to explain the purposes, benefits, and methods of segmentation for health organizations, and to illustrate the process of segmenting health populations based on preference coefficients from a discrete choice conjoint experiment (DCE) using an example study of prevention of cyberbullying among university students. We followed a two-level procedure for investigating segmentation incorporating several methods for forming segments in Level 1 using DCE preference coefficients and testing their quality, reproducibility, and usability by health decision makers. Covariates (demographic, behavioral, lifestyle, and health state variables) were included in Level 2 to further evaluate quality and to support the scoring of large databases and developing typing tools for assigning those in the relevant population, but not in the sample, to the segments. Several segmentation solution candidates were found during the Level 1 analysis, and the relationship of the preference coefficients to the segments was investigated using predictive methods. Those segmentations were tested for their quality and reproducibility and three were found to be very close in quality. While one seemed better than others in the Level 1 analysis, another was very similar in quality and proved ultimately better in predicting segment membership using covariates in Level 2. The two segments in the final solution were profiled for attributes that would support the development and acceptance of cyberbullying prevention programs among university

  2. Semi-automatic segmentation and tracking of CVH data.

    PubMed

    Qu, Yingge; Heng, Pheng Ann; Wong, Tien-Tsin

    2006-01-01

    Construction of speed function is crucial in applying level set method for medical image segmentation. We present a unified approach for segmenting and tracking of the high-resolution Chinese Visible Human (CVH) data. The underlying link of these two parts relies on the proposed variational framework for the speed function. Our proposed method can be applied to segmenting the first slice of the volume data, in the first step; It can also be adapted to track the boundaries of the homogeneous organs in the following serial images. In addition to promising segmentation results, the tracking procedure shows the advantage of less amount of user intervention.

  3. MBIS: multivariate Bayesian image segmentation tool.

    PubMed

    Esteban, Oscar; Wollny, Gert; Gorthi, Subrahmanyam; Ledesma-Carbayo, María-J; Thiran, Jean-Philippe; Santos, Andrés; Bach-Cuadra, Meritxell

    2014-07-01

    We present MBIS (Multivariate Bayesian Image Segmentation tool), a clustering tool based on the mixture of multivariate normal distributions model. MBIS supports multichannel bias field correction based on a B-spline model. A second methodological novelty is the inclusion of graph-cuts optimization for the stationary anisotropic hidden Markov random field model. Along with MBIS, we release an evaluation framework that contains three different experiments on multi-site data. We first validate the accuracy of segmentation and the estimated bias field for each channel. MBIS outperforms a widely used segmentation tool in a cross-comparison evaluation. The second experiment demonstrates the robustness of results on atlas-free segmentation of two image sets from scan-rescan protocols on 21 healthy subjects. Multivariate segmentation is more replicable than the monospectral counterpart on T1-weighted images. Finally, we provide a third experiment to illustrate how MBIS can be used in a large-scale study of tissue volume change with increasing age in 584 healthy subjects. This last result is meaningful as multivariate segmentation performs robustly without the need for prior knowledge.

  4. Pancreas and cyst segmentation

    NASA Astrophysics Data System (ADS)

    Dmitriev, Konstantin; Gutenko, Ievgeniia; Nadeem, Saad; Kaufman, Arie

    2016-03-01

    Accurate segmentation of abdominal organs from medical images is an essential part of surgical planning and computer-aided disease diagnosis. Many existing algorithms are specialized for the segmentation of healthy organs. Cystic pancreas segmentation is especially challenging due to its low contrast boundaries, variability in shape, location and the stage of the pancreatic cancer. We present a semi-automatic segmentation algorithm for pancreata with cysts. In contrast to existing automatic segmentation approaches for healthy pancreas segmentation which are amenable to atlas/statistical shape approaches, a pancreas with cysts can have even higher variability with respect to the shape of the pancreas due to the size and shape of the cyst(s). Hence, fine results are better attained with semi-automatic steerable approaches. We use a novel combination of random walker and region growing approaches to delineate the boundaries of the pancreas and cysts with respective best Dice coefficients of 85.1% and 86.7%, and respective best volumetric overlap errors of 26.0% and 23.5%. Results show that the proposed algorithm for pancreas and pancreatic cyst segmentation is accurate and stable.

  5. Keypoint Transfer Segmentation

    PubMed Central

    Toews, M.; Langs, G.; Wells, W.; Golland, P.

    2015-01-01

    We present an image segmentation method that transfers label maps of entire organs from the training images to the novel image to be segmented. The transfer is based on sparse correspondences between keypoints that represent automatically identified distinctive image locations. Our segmentation algorithm consists of three steps: (i) keypoint matching, (ii) voting-based keypoint labeling, and (iii) keypoint-based probabilistic transfer of organ label maps. We introduce generative models for the inference of keypoint labels and for image segmentation, where keypoint matches are treated as a latent random variable and are marginalized out as part of the algorithm. We report segmentation results for abdominal organs in whole-body CT and in contrast-enhanced CT images. The accuracy of our method compares favorably to common multi-atlas segmentation while offering a speed-up of about three orders of magnitude. Furthermore, keypoint transfer requires no training phase or registration to an atlas. The algorithm’s robustness enables the segmentation of scans with highly variable field-of-view. PMID:26221677

  6. Spleen volume on CT and the effect of abdominal trauma.

    PubMed

    Cruz-Romero, Cinthia; Agarwal, Sheela; Abujudeh, Hani H; Thrall, James; Hahn, Peter F

    2016-08-01

    The aim of this study is to determine the magnitude of change in spleen volume on CT in subjects sustaining blunt abdominal trauma without hemorrhage relative to patients without disease and how the spleen volumes are distributed. Sixty-seven subjects with blunt abdominal trauma and 101 control subjects were included in this retrospective single-center, IRB-approved, and HIPAA-compliant study. Patients with an injured spleen were excluded. Using a semiautomatic segmentation program, two readers computed spleen volumes from CT. Spleen volume distribution in male and female trauma and control cohorts were compared nonparametrically. Spleen volume plotted against height, weight, and age were analyzed by linear regression. The number of females and males are, respectively, 35 and 32 in trauma subjects and 69 and 32 among controls. Female trauma patients (49.6 years) were older than males (39.8 years) (p = 0.02). Distributions of spleen volume were not normal, skewed above their means, requiring a nonparametric comparison. Spleen volumes in trauma patients were smaller than those in controls with medians of 230 vs 294 mL in males(p < 0.006) and 163 vs 191 mL in females(p < 0.04). Spleen volume correlated positively with weight in females and with height in male controls, and negatively with age in male controls (p < 0.01). Variation in reproducibility and repeatability was acceptable at 1.5 and 4.9 %, respectively. Reader variation was 1.7 and 4.6 % for readers 1 and 2, respectively. The mean spleen volume in controls was 245 mL, the largest ever reported. Spleen volume decreases in response to blunt abdominal trauma. Spleen volumes are not normally distributed. Our population has the largest spleen volume reported in the literature, perhaps a consequence of the obesity epidemic. PMID:27166964

  7. Spleen volume on CT and the effect of abdominal trauma.

    PubMed

    Cruz-Romero, Cinthia; Agarwal, Sheela; Abujudeh, Hani H; Thrall, James; Hahn, Peter F

    2016-08-01

    The aim of this study is to determine the magnitude of change in spleen volume on CT in subjects sustaining blunt abdominal trauma without hemorrhage relative to patients without disease and how the spleen volumes are distributed. Sixty-seven subjects with blunt abdominal trauma and 101 control subjects were included in this retrospective single-center, IRB-approved, and HIPAA-compliant study. Patients with an injured spleen were excluded. Using a semiautomatic segmentation program, two readers computed spleen volumes from CT. Spleen volume distribution in male and female trauma and control cohorts were compared nonparametrically. Spleen volume plotted against height, weight, and age were analyzed by linear regression. The number of females and males are, respectively, 35 and 32 in trauma subjects and 69 and 32 among controls. Female trauma patients (49.6 years) were older than males (39.8 years) (p = 0.02). Distributions of spleen volume were not normal, skewed above their means, requiring a nonparametric comparison. Spleen volumes in trauma patients were smaller than those in controls with medians of 230 vs 294 mL in males(p < 0.006) and 163 vs 191 mL in females(p < 0.04). Spleen volume correlated positively with weight in females and with height in male controls, and negatively with age in male controls (p < 0.01). Variation in reproducibility and repeatability was acceptable at 1.5 and 4.9 %, respectively. Reader variation was 1.7 and 4.6 % for readers 1 and 2, respectively. The mean spleen volume in controls was 245 mL, the largest ever reported. Spleen volume decreases in response to blunt abdominal trauma. Spleen volumes are not normally distributed. Our population has the largest spleen volume reported in the literature, perhaps a consequence of the obesity epidemic.

  8. Segmentation of polycystic kidneys from MR images

    NASA Astrophysics Data System (ADS)

    Racimora, Dimitri; Vivier, Pierre-Hugues; Chandarana, Hersh; Rusinek, Henry

    2010-03-01

    Polycystic kidney disease (PKD) is a disorder characterized by the growth of numerous fluid filled cysts in the kidneys. Measuring cystic kidney volume is thus crucial to monitoring the evolution of the disease. While T2-weighted MRI delineates the organ, automatic segmentation is very difficult due to highly variable shape and image contrast. The interactive stereology methods used currently involve a compromise between segmentation accuracy and time. We have investigated semi-automated methods: active contours and a sub-voxel morphology based algorithm. Coronal T2- weighted images of 17 patients were acquired in four breath-holds using the HASTE sequence on a 1.5 Tesla MRI unit. The segmentation results were compared to ground truth kidney masks obtained as a consensus of experts. Automatic active contour algorithm yielded an average 22% +/- 8.6% volume error. A recently developed method (Bridge Burner) based on thresholding and constrained morphology failed to separate PKD from the spleen, yielding 37.4% +/- 8.7% volume error. Manual post-editing reduced the volume error to 3.2% +/- 0.8% for active contours and 3.2% +/- 0.6% for Bridge Burner. The total time (automated algorithm plus editing) was 15 min +/- 5 min for active contours and 19 min +/- 11 min for Bridge Burner. The average volume errors for stereology method were 5.9%, 6.2%, 5.4% for mesh size 6.6, 11, 16.5 mm. The average processing times were 17, 7, 4 min. These results show that nearly two-fold improvement in PKD segmentation accuracy over stereology technique can be achieved with a combination of active contours and postediting.

  9. Segmentation of the human spinal cord.

    PubMed

    De Leener, Benjamin; Taso, Manuel; Cohen-Adad, Julien; Callot, Virginie

    2016-04-01

    Segmenting the spinal cord contour is a necessary step for quantifying spinal cord atrophy in various diseases. Delineating gray matter (GM) and white matter (WM) is also useful for quantifying GM atrophy or for extracting multiparametric MRI metrics into specific WM tracts. Spinal cord segmentation in clinical research is not as developed as brain segmentation, however with the substantial improvement of MR sequences adapted to spinal cord MR investigations, the field of spinal cord MR segmentation has advanced greatly within the last decade. Segmentation techniques with variable accuracy and degree of complexity have been developed and reported in the literature. In this paper, we review some of the existing methods for cord and WM/GM segmentation, including intensity-based, surface-based, and image-based methods. We also provide recommendations for validating spinal cord segmentation techniques, as it is important to understand the intrinsic characteristics of the methods and to evaluate their performance and limitations. Lastly, we illustrate some applications in the healthy and pathological spinal cord. One conclusion of this review is that robust and automatic segmentation is clinically relevant, as it would allow for longitudinal and group studies free from user bias as well as reproducible multicentric studies in large populations, thereby helping to further our understanding of the spinal cord pathophysiology and to develop new criteria for early detection of subclinical evolution for prognosis prediction and for patient management. Another conclusion is that at the present time, no single method adequately segments the cord and its substructure in all the cases encountered (abnormal intensities, loss of contrast, deformation of the cord, etc.). A combination of different approaches is thus advised for future developments, along with the introduction of probabilistic shape models. Maturation of standardized frameworks, multiplatform availability, inclusion

  10. Image enhancement and segmentation of fluid-filled structures in 3D ultrasound images

    NASA Astrophysics Data System (ADS)

    Chalana, Vikram; Dudycha, Stephen; McMorrow, Gerald

    2003-05-01

    Segmentation of fluid-filled structures, such as the urinary bladder, from three-dimensional ultrasound images is necessary for measuring their volume. This paper describes a system for image enhancement, segmentation and volume measurement of fluid-filled structures on 3D ultrasound images. The system was applied for the measurement of urinary bladder volume. Results show an average error of less than 10% in the estimation of the total bladder volume.

  11. Image segmentation survey

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The methodologies and capabilities of image segmentation techniques are reviewed. Single linkage schemes, hybrid linkage schemes, centroid linkage schemes, histogram mode seeking, spatial clustering, and split and merge schemes are addressed.

  12. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

  13. Squaring a Circular Segment

    ERIC Educational Resources Information Center

    Gordon, Russell

    2008-01-01

    Consider a circular segment (the smaller portion of a circle cut off by one of its chords) with chord length c and height h (the greatest distance from a point on the arc of the circle to the chord). Is there a simple formula involving c and h that can be used to closely approximate the area of this circular segment? Ancient Chinese and Egyptian…

  14. Segmented pyroelector detector

    DOEpatents

    Stotlar, S.C.; McLellan, E.J.

    1981-01-21

    A pyroelectric detector is described which has increased voltage output and improved responsivity over equivalent size detectors. The device comprises a plurality of edge-type pyroelectric detectors which have a length which is much greater than the width of the segments between the edge-type electrodes. External circuitry connects the pyroelectric detector segments in parallel to provide a single output which maintains 50 ohm impedance characteristics.

  15. Geometry Guided Segmentation

    NASA Astrophysics Data System (ADS)

    Dunn, Stanley M.; Liang, Tajen

    1989-03-01

    Our overall goal is to develop an image understanding system for automatically interpreting dental radiographs. This paper describes the module that integrates the intrinsic image data to form the region adjacency graph that represents the image. The specific problem is to develop a robust method for segmenting the image into small regions that do not overlap anatomical boundaries. Classical algorithms for finding homogeneous regions (i.e., 2 class segmentation or connected components) will not always yield correct results since blurred edges can cause adjacent anatomical regions to be labeled as one region. This defect is a problem in this and other applications where an object count is necessary. Our solution to the problem is to guide the segmentation by intrinsic properties of the constituent objects. The module takes a set of intrinsic images as arguments. A connected components-like algorithm is performed, but the connectivity relation is not 4- or 8-neighbor connectivity in binary images; the connectivity is defined in terms of the intrinsic image data. We shall describe both the classical method and the modified segmentation procedures, and present experiments using both algorithms. Our experiments show that for the dental radiographs a segmentation using gray level data in conjunction with edges of the surfaces of teeth give a robust and reliable segmentation.

  16. Comparative study of diverse model building strategies for 3D-ASM segmentation of dynamic gated SPECT data

    NASA Astrophysics Data System (ADS)

    Tobon-Gomez, C.; Butakoff, C.; Ordas, S.; Aguade, S.; Frangi, A. F.

    2007-03-01

    Over the course of the last two decades, myocardial perfusion with Single Photon Emission Computed Tomography (SPECT) has emerged as an established and well-validated method for assessing myocardial ischemia, viability, and function. Gated-SPECT imaging integrates traditional perfusion information along with global left ventricular function. Despite of these advantages, inherent limitations of SPECT imaging yield a challenging segmentation problem, since an error of only one voxel along the chamber surface may generate a huge difference in volume calculation. In previous works we implemented a 3-D statistical model-based algorithm for Left Ventricle (LV) segmentation of in dynamic perfusion SPECT studies. The present work evaluates the relevance of training a different Active Shape Model (ASM) for each frame of the gated SPECT imaging acquisition in terms of their subsequent segmentation accuracy. Models are subsequently employed to segment the LV cavity of gated SPECT studies of a virtual population. The evaluation is accomplished by comparing point-to-surface (P2S) and volume errors, both against a proper Gold Standard. The dataset comprised 40 voxel phantoms (NCAT, Johns Hopkins, University of of North Carolina). Monte-Carlo simulations were generated with SIMIND (Lund University) and reconstructed to tomographic slices with ASPIRE (University of Michigan).

  17. Which mantle below the active rift segments in Afar?

    NASA Astrophysics Data System (ADS)

    Pik, Raphael; Stab, Martin; Ancellin, Marie-Anne; Sarah, Medynski; Cloquet, Christophe; Vye-Brown, Charlotte; Ayalew, Dereje; Chazot, Gilles; Bellahsen, Nicolas; Leroy, Sylvie

    2014-05-01

    The evolution of mantle sources beneath the Ethiopian volcanic province has long been discussed and debated with a long-lived controversy in identifying mantle reservoirs and locating them in the mantle. One interpretation of the isotopic composition of erupted lavas considers that the Afar mantle plume composition is best expressed by recent lavas from Afar and Gulf of Aden (e.g. Erta Ale, Manda Inakir and the 45°E torus anomaly on the Gulf of Aden) implying that all other volcanics (including other active segments and the initial flood basalt province) result from mixing of this plume component with additional lithospheric and asthenospheric components. A completely opposite view considers that the initial Oligocene continental flood basalts best represent the isotopic composition of the Afar mantle plume, which is subsequently mixed in various proportions with continental lithospheric mantle for generating some of the specific signature of Miocene and Quaternary volcanics. The precise and correct identification of mantle components involved in the generation of magmas is of particular importance because this is the only way to document the participation of mantle during extension and its potential role in break-up processes. In this contribution we provide new isotopic data for central Afar and we revisit the whole data set of the Ethiopian volcanic province in order to: (i) precisely identify the distinct mantle components implicated and (ii) discuss their location and evolution not only considering geochemical mixings, but also taking into account additional characteristics of erupted magmatic suites (volumes, location and relationships with amount of extension and segmentation). This new interpretation of geochemical data allows reconsidering the evolution of mantle in the course of rift evolution. In terms of mantle sources, two populations of active segments are frontally opposed in the volcanic province: those that share exactly the same composition with

  18. Speed tuning of motion segmentation and discrimination

    NASA Technical Reports Server (NTRS)

    Masson, G. S.; Mestre, D. R.; Stone, L. S.

    1999-01-01

    Motion transparency requires that the visual system distinguish different motion vectors and selectively integrate similar motion vectors over space into the perception of multiple surfaces moving through or over each other. Using large-field (7 degrees x 7 degrees) displays containing two populations of random-dots moving in the same (horizontal) direction but at different speeds, we examined speed-based segmentation by measuring the speed difference above which observers can perceive two moving surfaces. We systematically investigated this 'speed-segmentation' threshold as a function of speed and stimulus duration, and found that it increases sharply for speeds above approximately 8 degrees/s. In addition, speed-segmentation thresholds decrease with stimulus duration out to approximately 200 ms. In contrast, under matched conditions, speed-discrimination thresholds stay low at least out to 16 degrees/s and decrease with increasing stimulus duration at a faster rate than for speed segmentation. Thus, motion segmentation and motion discrimination exhibit different speed selectivity and different temporal integration characteristics. Results are discussed in terms of the speed preferences of different neuronal populations within the primate visual cortex.

  19. Automatic partitioning of head CTA for enabling segmentation

    NASA Astrophysics Data System (ADS)

    Suryanarayanan, Srikanth; Mullick, Rakesh; Mallya, Yogish; Kamath, Vidya; Nagaraj, Nithin

    2004-05-01

    Radiologists perform a CT Angiography procedure to examine vascular structures and associated pathologies such as aneurysms. Volume rendering is used to exploit volumetric capabilities of CT that provides complete interactive 3-D visualization. However, bone forms an occluding structure and must be segmented out. The anatomical complexity of the head creates a major challenge in the segmentation of bone and vessel. An analysis of the head volume reveals varying spatial relationships between vessel and bone that can be separated into three sub-volumes: "proximal", "middle", and "distal". The "proximal" and "distal" sub-volumes contain good spatial separation between bone and vessel (carotid referenced here). Bone and vessel appear contiguous in the "middle" partition that remains the most challenging region for segmentation. The partition algorithm is used to automatically identify these partition locations so that different segmentation methods can be developed for each sub-volume. The partition locations are computed using bone, image entropy, and sinus profiles along with a rule-based method. The algorithm is validated on 21 cases (varying volume sizes, resolution, clinical sites, pathologies) using ground truth identified visually. The algorithm is also computationally efficient, processing a 500+ slice volume in 6 seconds (an impressive 0.01 seconds / slice) that makes it an attractive algorithm for pre-processing large volumes. The partition algorithm is integrated into the segmentation workflow. Fast and simple algorithms are implemented for processing the "proximal" and "distal" partitions. Complex methods are restricted to only the "middle" partition. The partitionenabled segmentation has been successfully tested and results are shown from multiple cases.

  20. Scorpion image segmentation system

    NASA Astrophysics Data System (ADS)

    Joseph, E.; Aibinu, A. M.; Sadiq, B. A.; Bello Salau, H.; Salami, M. J. E.

    2013-12-01

    Death as a result of scorpion sting has been a major public health problem in developing countries. Despite the high rate of death as a result of scorpion sting, little report exists in literature of intelligent device and system for automatic detection of scorpion. This paper proposed a digital image processing approach based on the floresencing characteristics of Scorpion under Ultra-violet (UV) light for automatic detection and identification of scorpion. The acquired UV-based images undergo pre-processing to equalize uneven illumination and colour space channel separation. The extracted channels are then segmented into two non-overlapping classes. It has been observed that simple thresholding of the green channel of the acquired RGB UV-based image is sufficient for segmenting Scorpion from other background components in the acquired image. Two approaches to image segmentation have also been proposed in this work, namely, the simple average segmentation technique and K-means image segmentation. The proposed algorithm has been tested on over 40 UV scorpion images obtained from different part of the world and results obtained show an average accuracy of 97.7% in correctly classifying the pixel into two non-overlapping clusters. The proposed 1system will eliminate the problem associated with some of the existing manual approaches presently in use for scorpion detection.

  1. Cooperative processes in image segmentation

    NASA Technical Reports Server (NTRS)

    Davis, L. S.

    1982-01-01

    Research into the role of cooperative, or relaxation, processes in image segmentation is surveyed. Cooperative processes can be employed at several levels of the segmentation process as a preprocessing enhancement step, during supervised or unsupervised pixel classification and, finally, for the interpretation of image segments based on segment properties and relations.

  2. Origin of segmentation in the human structure.

    PubMed

    Ermolenko, Alexander E; Perepada, Elena A

    2006-01-01

    Crystallographic analysis of biological and non-biological minerals does not reveal any significant differences between the two, which is indicative of common crystallization processes. It can be supposed that the human organism is a biocrystalloid in a sense that it is regarded both at the level of the whole organism and individual cells as a composite entity consisting of a crystal-like structure and pericrystalline medium. A similarity can be found between the growing layer of a crystal in the crystal-forming medium and a cell structure with liquid washing it. A mineral organism therefore can be regarded as the active superficial part of a crystal taken together with pericrystalline crystal-forming medium which controls crystal growth and modifies the system depending on the structure of the growing system. Aggregation is one of the fundamental features of minerals as they are found primarily not only as separate objects but also as aggregates, i.e. regular cohesive masses or synmineralogical systems. Ability to aggregation in an orderly way is expressed as self-organization. This feature is inherent not only to compound molecules but also to associates of a higher order. The cell biology has shown that when similar cells touch each other they tend to cohere forming aggregates characteristic of the given cell population. Similar live systems and their components that perform the same function have an ability to integrate and form firstly a conglomerate (colony) and then an organism. Integration explains association of multi-segmented entities into a single organism and the resulting structure would consists of the two groups of segments, i.e. appearance of an organism consisting of two different but of the same type specimens, each of which had different number of segments. Phylogenetically, an early precursor of the man evolved from a simple cell into an integrated multi-segment organism through several stages--initially a simple cell, then a cell colony, then

  3. Head segmentation in vertebrates

    PubMed Central

    Kuratani, Shigeru; Schilling, Thomas

    2008-01-01

    Classic theories of vertebrate head segmentation clearly exemplify the idealistic nature of comparative embryology prior to the 20th century. Comparative embryology aimed at recognizing the basic, primary structure that is shared by all vertebrates, either as an archetype or an ancestral developmental pattern. Modern evolutionary developmental (Evo-Devo) studies are also based on comparison, and therefore have a tendency to reduce complex embryonic anatomy into overly simplified patterns. Here again, a basic segmental plan for the head has been sought among chordates. We convened a symposium that brought together leading researchers dealing with this problem, in a number of different evolutionary and developmental contexts. Here we give an overview of the outcome and the status of the field in this modern era of Evo-Devo. We emphasize the fact that the head segmentation problem is not fully resolved, and we discuss new directions in the search for hints for a way out of this maze. PMID:20607135

  4. Phasing a segmented telescope

    NASA Astrophysics Data System (ADS)

    Paykin, Irina; Yacobi, Lee; Adler, Joan; Ribak, Erez N.

    2015-02-01

    A crucial part of segmented or multiple-aperture systems is control of the optical path difference between the segments or subapertures. In order to achieve optimal performance we have to phase subapertures to within a fraction of the wavelength, and this requires high accuracy of positioning for each subaperture. We present simulations and hardware realization of a simulated annealing algorithm in an active optical system with sparse segments. In order to align the optical system we applied the optimization algorithm to the image itself. The main advantage of this method over traditional correction methods is that wave-front-sensing hardware and software are no longer required, making the optical and mechanical system much simpler. The results of simulations and laboratory experiments demonstrate the ability of this optimization algorithm to correct both piston and tip-tilt errors.

  5. Segmented annular combustor

    DOEpatents

    Reider, Samuel B.

    1979-01-01

    An industrial gas turbine engine includes an inclined annular combustor made up of a plurality of support segments each including inner and outer walls of trapezoidally configured planar configuration extents and including side flanges thereon interconnected by means of air cooled connector bolt assemblies to form a continuous annular combustion chamber therebetween and wherein an air fuel mixing chamber is formed at one end of the support segments including means for directing and mixing fuel within a plenum and a perforated header plate for directing streams of air and fuel mixture into the combustion chamber; each of the outer and inner walls of each of the support segments having a ribbed lattice with tracks slidably supporting porous laminated replaceable panels and including pores therein for distributing combustion air into the combustion chamber while cooling the inner surface of each of the panels by transpiration cooling thereof.

  6. Liver segmentation in contrast enhanced CT data using graph cuts and interactive 3D segmentation refinement methods

    SciTech Connect

    Beichel, Reinhard; Bornik, Alexander; Bauer, Christian; Sorantin, Erich

    2012-03-15

    Purpose: Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. Methods: A graph cuts segmentation method was combined with a three-dimensional virtual reality based segmentation refinement approach. The developed interactive segmentation system allowed the user to manipulate volume chunks and/or surfaces instead of 2D contours in cross-sectional images (i.e, slice-by-slice). The method was evaluated on twenty routinely acquired portal-phase contrast enhanced multislice computed tomography (CT) data sets. An independent reference was generated by utilizing a currently clinically utilized slice-by-slice segmentation method. After 1 h of introduction to the developed segmentation system, three experts were asked to segment all twenty data sets with the proposed method. Results: Compared to the independent standard, the relative volumetric segmentation overlap error averaged over all three experts and all twenty data sets was 3.74%. Liver segmentation required on average 16 min of user interaction per case. The calculated relative volumetric overlap errors were not found to be significantly different [analysis of variance (ANOVA) test, p = 0.82] between experts who utilized the proposed 3D system. In contrast, the time required by each expert for segmentation was found to be significantly different (ANOVA test, p = 0.0009). Major differences between generated segmentations and independent references were observed in areas were vessels enter or leave the liver and no accepted criteria for defining liver boundaries exist. In comparison, slice-by-slice based generation of the independent standard utilizing a live wire tool took 70.1 min on average. A standard 2D segmentation refinement approach applied to all twenty data sets required on average 38.2 min of

  7. Automatic segmentation of the striatum and globus pallidus using MIST: Multimodal Image Segmentation Tool.

    PubMed

    Visser, Eelke; Keuken, Max C; Douaud, Gwenaëlle; Gaura, Veronique; Bachoud-Levi, Anne-Catherine; Remy, Philippe; Forstmann, Birte U; Jenkinson, Mark

    2016-01-15

    Accurate segmentation of the subcortical structures is frequently required in neuroimaging studies. Most existing methods use only a T1-weighted MRI volume to segment all supported structures and usually rely on a database of training data. We propose a new method that can use multiple image modalities simultaneously and a single reference segmentation for initialisation, without the need for a manually labelled training set. The method models intensity profiles in multiple images around the boundaries of the structure after nonlinear registration. It is trained using a set of unlabelled training data, which may be the same images that are to be segmented, and it can automatically infer the location of the physical boundary using user-specified priors. We show that the method produces high-quality segmentations of the striatum, which is clearly visible on T1-weighted scans, and the globus pallidus, which has poor contrast on such scans. The method compares favourably to existing methods, showing greater overlap with manual segmentations and better consistency. PMID:26477650

  8. Lung lobe modeling and segmentation with individualized surface meshes

    NASA Astrophysics Data System (ADS)

    Blaffert, Thomas; Barschdorf, Hans; von Berg, Jens; Dries, Sebastian; Franz, Astrid; Klinder, Tobias; Lorenz, Cristian; Renisch, Steffen; Wiemker, Rafael

    2008-03-01

    An automated segmentation of lung lobes in thoracic CT images is of interest for various diagnostic purposes like the quantification of emphysema or the localization of tumors within the lung. Although the separating lung fissures are visible in modern multi-slice CT-scanners, their contrast in the CT-image often does not separate the lobes completely. This makes it impossible to build a reliable segmentation algorithm without additional information. Our approach uses general anatomical knowledge represented in a geometrical mesh model to construct a robust lobe segmentation, which even gives reasonable estimates of lobe volumes if fissures are not visible at all. The paper describes the generation of the lung model mesh including lobes by an average volume model, its adaptation to individual patient data using a special fissure feature image, and a performance evaluation over a test data set showing an average segmentation accuracy of 1 to 3 mm.

  9. Bayesian segmentation of brainstem structures in MRI.

    PubMed

    Iglesias, Juan Eugenio; Van Leemput, Koen; Bhatt, Priyanka; Casillas, Christen; Dutt, Shubir; Schuff, Norbert; Truran-Sacrey, Diana; Boxer, Adam; Fischl, Bruce

    2015-06-01

    In this paper we present a method to segment four brainstem structures (midbrain, pons, medulla oblongata and superior cerebellar peduncle) from 3D brain MRI scans. The segmentation method relies on a probabilistic atlas of the brainstem and its neighboring brain structures. To build the atlas, we combined a dataset of 39 scans with already existing manual delineations of the whole brainstem and a dataset of 10 scans in which the brainstem structures were manually labeled with a protocol that was specifically designed for this study. The resulting atlas can be used in a Bayesian framework to segment the brainstem structures in novel scans. Thanks to the generative nature of the scheme, the segmentation method is robust to changes in MRI contrast or acquisition hardware. Using cross validation, we show that the algorithm can segment the structures in previously unseen T1 and FLAIR scans with great accuracy (mean error under 1mm) and robustness (no failures in 383 scans including 168 AD cases). We also indirectly evaluate the algorithm with a experiment in which we study the atrophy of the brainstem in aging. The results show that, when used simultaneously, the volumes of the midbrain, pons and medulla are significantly more predictive of age than the volume of the entire brainstem, estimated as their sum. The results also demonstrate that the method can detect atrophy patterns in the brainstem structures that have been previously described in the literature. Finally, we demonstrate that the proposed algorithm is able to detect differential effects of AD on the brainstem structures. The method will be implemented as part of the popular neuroimaging package FreeSurfer.

  10. Segmentation of thermographic images of hands using a genetic algorithm

    NASA Astrophysics Data System (ADS)

    Ghosh, Payel; Mitchell, Melanie; Gold, Judith

    2010-01-01

    This paper presents a new technique for segmenting thermographic images using a genetic algorithm (GA). The individuals of the GA also known as chromosomes consist of a sequence of parameters of a level set function. Each chromosome represents a unique segmenting contour. An initial population of segmenting contours is generated based on the learned variation of the level set parameters from training images. Each segmenting contour (an individual) is evaluated for its fitness based on the texture of the region it encloses. The fittest individuals are allowed to propagate to future generations of the GA run using selection, crossover and mutation. The dataset consists of thermographic images of hands of patients suffering from upper extremity musculo-skeletal disorders (UEMSD). Thermographic images are acquired to study the skin temperature as a surrogate for the amount of blood flow in the hands of these patients. Since entire hands are not visible on these images, segmentation of the outline of the hands on these images is typically performed by a human. In this paper several different methods have been tried for segmenting thermographic images: Gabor-wavelet-based texture segmentation method, the level set method of segmentation and our GA which we termed LSGA because it combines level sets with genetic algorithms. The results show a comparative evaluation of the segmentation performed by all the methods. We conclude that LSGA successfully segments entire hands on images in which hands are only partially visible.

  11. Robust system for human airway-tree segmentation

    NASA Astrophysics Data System (ADS)

    Graham, Michael W.; Gibbs, Jason D.; Higgins, William E.

    2008-03-01

    Robust and accurate segmentation of the human airway tree from multi-detector computed-tomography (MDCT) chest scans is vital for many pulmonary-imaging applications. As modern MDCT scanners can detect hundreds of airway tree branches, manual segmentation and semi-automatic segmentation requiring significant user intervention are impractical for producing a full global segmentation. Fully-automated methods, however, may fail to extract small peripheral airways. We propose an automatic algorithm that searches the entire lung volume for airway branches and poses segmentation as a global graph-theoretic optimization problem. The algorithm has shown strong performance on 23 human MDCT chest scans acquired by a variety of scanners and reconstruction kernels. Visual comparisons with adaptive region-growing results and quantitative comparisons with manually-defined trees indicate a high sensitivity to peripheral airways and a low false-positive rate. In addition, we propose a suite of interactive segmentation tools for cleaning and extending critical areas of the automatically segmented result. These interactive tools have potential application for image-based guidance of bronchoscopy to the periphery, where small, terminal branches can be important visual landmarks. Together, the automatic segmentation algorithm and interactive tool suite comprise a robust system for human airway-tree segmentation.

  12. Review methods for image segmentation from computed tomography images

    SciTech Connect

    Mamat, Nurwahidah; Rahman, Wan Eny Zarina Wan Abdul; Soh, Shaharuddin Cik; Mahmud, Rozi

    2014-12-04

    Image segmentation is a challenging process in order to get the accuracy of segmentation, automation and robustness especially in medical images. There exist many segmentation methods that can be implemented to medical images but not all methods are suitable. For the medical purposes, the aims of image segmentation are to study the anatomical structure, identify the region of interest, measure tissue volume to measure growth of tumor and help in treatment planning prior to radiation therapy. In this paper, we present a review method for segmentation purposes using Computed Tomography (CT) images. CT images has their own characteristics that affect the ability to visualize anatomic structures and pathologic features such as blurring of the image and visual noise. The details about the methods, the goodness and the problem incurred in the methods will be defined and explained. It is necessary to know the suitable segmentation method in order to get accurate segmentation. This paper can be a guide to researcher to choose the suitable segmentation method especially in segmenting the images from CT scan.

  13. Advanced level set segmentation of the right atrium in MR

    NASA Astrophysics Data System (ADS)

    Chen, Siqi; Kohlberger, Timo; Kirchberg, Klaus J.

    2011-03-01

    Atrial fibrillation is a common heart arrhythmia, and can be effectively treated with ablation. Ablation planning requires 3D models of the patient's left atrium (LA) and/or right atrium (RA), therefore an automatic segmentation procedure to retrieve these models is desirable. In this study, we investigate the use of advanced level set segmentation approaches to automatically segment RA in magnetic resonance angiographic (MRA) volume images. Low contrast to noise ratio makes the boundary between the RA and the nearby structures nearly indistinguishable. Therefore, pure data driven segmentation approaches such as watershed and ChanVese methods are bound to fail. Incorporating training shapes through PCA modeling to constrain the segmentation is one popular solution, and is also used in our segmentation framework. The shape parameters from PCA are optimized with a global histogram based energy model. However, since the shape parameters span a much smaller space, it can not capture fine details of the shape. Therefore, we employ a second refinement step after the shape based segmentation stage, which follows closely the recent work of localized appearance model based techniques. The local appearance model is established through a robust point tracking mechanism and is learned through landmarks embedded on the surface of training shapes. The key contribution of our work is the combination of a statistical shape prior and a localized appearance prior for level set segmentation of the right atrium from MRA. We test this two step segmentation framework on porcine RA to verify the algorithm.

  14. Consistent cortical reconstruction and multi-atlas brain segmentation.

    PubMed

    Huo, Yuankai; Plassard, Andrew J; Carass, Aaron; Resnick, Susan M; Pham, Dzung L; Prince, Jerry L; Landman, Bennett A

    2016-09-01

    Whole brain segmentation and cortical surface reconstruction are two essential techniques for investigating the human brain. Spatial inconsistences, which can hinder further integrated analyses of brain structure, can result due to these two tasks typically being conducted independently of each other. FreeSurfer obtains self-consistent whole brain segmentations and cortical surfaces. It starts with subcortical segmentation, then carries out cortical surface reconstruction, and ends with cortical segmentation and labeling. However, this "segmentation to surface to parcellation" strategy has shown limitations in various cohorts such as older populations with large ventricles. In this work, we propose a novel "multi-atlas segmentation to surface" method called Multi-atlas CRUISE (MaCRUISE), which achieves self-consistent whole brain segmentations and cortical surfaces by combining multi-atlas segmentation with the cortical reconstruction method CRUISE. A modification called MaCRUISE(+) is designed to perform well when white matter lesions are present. Comparing to the benchmarks CRUISE and FreeSurfer, the surface accuracy of MaCRUISE and MaCRUISE(+) is validated using two independent datasets with expertly placed cortical landmarks. A third independent dataset with expertly delineated volumetric labels is employed to compare segmentation performance. Finally, 200MR volumetric images from an older adult sample are used to assess the robustness of MaCRUISE and FreeSurfer. The advantages of MaCRUISE are: (1) MaCRUISE constructs self-consistent voxelwise segmentations and cortical surfaces, while MaCRUISE(+) is robust to white matter pathology. (2) MaCRUISE achieves more accurate whole brain segmentations than independently conducting the multi-atlas segmentation. (3) MaCRUISE is comparable in accuracy to FreeSurfer (when FreeSurfer does not exhibit global failures) while achieving greater robustness across an older adult population. MaCRUISE has been made freely

  15. Consistent cortical reconstruction and multi-atlas brain segmentation.

    PubMed

    Huo, Yuankai; Plassard, Andrew J; Carass, Aaron; Resnick, Susan M; Pham, Dzung L; Prince, Jerry L; Landman, Bennett A

    2016-09-01

    Whole brain segmentation and cortical surface reconstruction are two essential techniques for investigating the human brain. Spatial inconsistences, which can hinder further integrated analyses of brain structure, can result due to these two tasks typically being conducted independently of each other. FreeSurfer obtains self-consistent whole brain segmentations and cortical surfaces. It starts with subcortical segmentation, then carries out cortical surface reconstruction, and ends with cortical segmentation and labeling. However, this "segmentation to surface to parcellation" strategy has shown limitations in various cohorts such as older populations with large ventricles. In this work, we propose a novel "multi-atlas segmentation to surface" method called Multi-atlas CRUISE (MaCRUISE), which achieves self-consistent whole brain segmentations and cortical surfaces by combining multi-atlas segmentation with the cortical reconstruction method CRUISE. A modification called MaCRUISE(+) is designed to perform well when white matter lesions are present. Comparing to the benchmarks CRUISE and FreeSurfer, the surface accuracy of MaCRUISE and MaCRUISE(+) is validated using two independent datasets with expertly placed cortical landmarks. A third independent dataset with expertly delineated volumetric labels is employed to compare segmentation performance. Finally, 200MR volumetric images from an older adult sample are used to assess the robustness of MaCRUISE and FreeSurfer. The advantages of MaCRUISE are: (1) MaCRUISE constructs self-consistent voxelwise segmentations and cortical surfaces, while MaCRUISE(+) is robust to white matter pathology. (2) MaCRUISE achieves more accurate whole brain segmentations than independently conducting the multi-atlas segmentation. (3) MaCRUISE is comparable in accuracy to FreeSurfer (when FreeSurfer does not exhibit global failures) while achieving greater robustness across an older adult population. MaCRUISE has been made freely

  16. Hyperspectral imagery and segmentation

    NASA Astrophysics Data System (ADS)

    Wellman, Mark C.; Nasrabadi, Nasser M.

    2002-07-01

    Hyperspectral imagery (HSI), a passive infrared imaging technique which creates images of fine resolution across the spectrum is currently being considered for Army tactical applications. An important tactical application of infra-red (IR) hyperspectral imagery is the detection of low contrast targets, including those targets that may employ camouflage, concealment and deception (CCD) techniques [1,2]. Spectral reflectivity characteristics were used for efficient segmentation between different materials such as painted metal, vegetation and soil for visible to near IR bands in the range of 0.46-1.0 microns as shown previously by Kwon et al [3]. We are currently investigating the HSI where the wavelength spans from 7.5-13.7 microns. The energy in this range of wavelengths is almost entirely emitted rather than reflected, therefore, the gray level of a pixel is a function of the temperature and emissivity of the object. This is beneficial since light level and reflection will not need to be considered in the segmentation. We will present results of a step-wise segmentation analysis on the long-wave infrared (LWIR) hyperspectrum utilizing various classifier architectures applied to both the full-band, broad-band and narrow-band features derived from the Spatially Enhanced Broadband Array Spectrograph System (SEBASS) data base. Stepwise segmentation demonstrates some of the difficulties in the multi-class case. These results give an indication of the added capability the hyperspectral imagery and associated algorithms will bring to bear on the target acquisition problem.

  17. Automated 3D renal segmentation based on image partitioning

    NASA Astrophysics Data System (ADS)

    Yeghiazaryan, Varduhi; Voiculescu, Irina D.

    2016-03-01

    Despite several decades of research into segmentation techniques, automated medical image segmentation is barely usable in a clinical context, and still at vast user time expense. This paper illustrates unsupervised organ segmentation through the use of a novel automated labelling approximation algorithm followed by a hypersurface front propagation method. The approximation stage relies on a pre-computed image partition forest obtained directly from CT scan data. We have implemented all procedures to operate directly on 3D volumes, rather than slice-by-slice, because our algorithms are dimensionality-independent. The results picture segmentations which identify kidneys, but can easily be extrapolated to other body parts. Quantitative analysis of our automated segmentation compared against hand-segmented gold standards indicates an average Dice similarity coefficient of 90%. Results were obtained over volumes of CT data with 9 kidneys, computing both volume-based similarity measures (such as the Dice and Jaccard coefficients, true positive volume fraction) and size-based measures (such as the relative volume difference). The analysis considered both healthy and diseased kidneys, although extreme pathological cases were excluded from the overall count. Such cases are difficult to segment both manually and automatically due to the large amplitude of Hounsfield unit distribution in the scan, and the wide spread of the tumorous tissue inside the abdomen. In the case of kidneys that have maintained their shape, the similarity range lies around the values obtained for inter-operator variability. Whilst the procedure is fully automated, our tools also provide a light level of manual editing.

  18. Leukocytes segmentation using Markov random fields.

    PubMed

    Reta, C; Gonzalez, J A; Diaz, R; Guichard, J S

    2011-01-01

    The segmentation of leukocytes and their components plays an important role in the extraction of geometric, texture, and morphological characteristics used to diagnose different diseases. This paper presents a novel method to segment leukocytes and their respective nucleus and cytoplasm from microscopic bone marrow leukemia cell images. Our method uses color and texture contextual information of image pixels to extract cellular elements from images, which show heterogeneous color and texture staining and high-cell population. The CIEL ( ∗ ) a ( ∗ ) b ( ∗ ) color space is used to extract color features, whereas a 2D Wold Decomposition model is applied to extract structural and stochastic texture features. The color and texture contextual information is incorporated into an unsupervised binary Markov Random Field segmentation model. Experimental results show the performance of the proposed method on both synthetic and real leukemia cell images. An average accuracy of 95% was achieved in the segmentation of real cell images by comparing those results with manually segmented cell images.

  19. Normative data for subcortical regional volumes over the lifetime of the adult human brain.

    PubMed

    Potvin, Olivier; Mouiha, Abderazzak; Dieumegarde, Louis; Duchesne, Simon

    2016-08-15

    Normative data for volumetric estimates of brain structures are necessary to adequately assess brain volume alterations in individuals with suspected neurological or psychiatric conditions. Although many studies have described age and sex effects in healthy individuals for brain morphometry assessed via magnetic resonance imaging, proper normative values allowing to quantify potential brain abnormalities are needed. We developed norms for volumetric estimates of subcortical brain regions based on cross-sectional magnetic resonance scans from 2790 healthy individuals aged 18 to 94years using 23 samples provided by 21 independent research groups. The segmentation was conducted using FreeSurfer, a widely used and freely available automated segmentation software. Models predicting subcortical regional volumes of each hemisphere were produced including age, sex, estimated total intracranial volume (eTIV), scanner manufacturer, magnetic field strength, and interactions as predictors. The mean explained variance by the models was 48%. For most regions, age, sex and eTIV predicted most of the explained variance while manufacturer, magnetic field strength and interactions predicted a limited amount. Estimates of the expected volumes of an individual based on its characteristics and the scanner characteristics can be obtained using derived formulas. For a new individual, significance test for volume abnormality, effect size and estimated percentage of the normative population with a smaller volume can be obtained. Normative values were validated in independent samples of healthy adults and in adults with Alzheimer's disease and schizophrenia. PMID:27165761

  20. A C++ framework for creating tissue specific segmentation-pipelines

    NASA Astrophysics Data System (ADS)

    Pfeifer, Bernhard; Hanser, Friedrich; Seger, Michael; Hintermueller, Christoph; Modre-Osprian, Robert; Fischer, Gerald; Muehlthaler, Hannes; Trieb, Thomas; Tilg, Bernhard

    2005-04-01

    For a clinical application of the inverse problem of electrocardiography, a flexible and fast generation of a patient's volume conductor model is essential. The volume conductor model includes compartments like chest, lungs, ventricles, atria and the associated blood masses. It is a challenging task to create an automatic or semi-automatic segmentation procedure for each compartment. For the extraction of the lungs, as one example, a region growing algorithm can be used, to extract the blood masses of the ventricles Active Appearance Models may succeed, and to construct the atrial myocardium a multiplicity of operations are necessary. These examples illustrate that there is no common method that will succeed for all compartments like a least common denominator. Another problem is the automatization of combining different methods and the origination of a segmentation pipeline in order to extract a compartment and, accordingly, the desired model - in our case the complete volume conductor model for estimating the spread of electrical excitation in the patient's heart. On account of this, we developed a C++ framework and a special application with the goal of creating tissue-specific segmentation pipelines. The C++ framework uses different standard frameworks like DCMTK for handling medical images (http://dicom.offis.de/dcmtk.php.en), ITK (http://www.itk.org/) for some segmentation methods, and Qt (http://www.trolltech.com/) for creating user interfaces. Our Medical Segmentation Toolkit (MST) enables to combine different segmentation techniques for each compartment. In addition, the framework enables to create user-defined compartment pipelines.

  1. Solvent transport through hard-soft segmented polymer nanocomposites.

    PubMed

    Rath, Sangram K; Edatholath, Saji S; Patro, T Umasankar; Sudarshan, Kathi; Sastry, P U; Pujari, Pradeep K; Harikrishnan, G

    2016-01-28

    We conducted transport studies of a common solvent (toluene) in its condensed state, through a model hard-soft segmented polyurethane-clay nanocomposite. The solvent diffusivity is observed to be non-monotonic in a functional relationship with a filler volume fraction. In stark contrast, both classical tortuous path theory based geometric calculations and free volume measurements suggest the normally expected monotonic decrease in diffusivity with increase in clay volume fraction. Large deviations between experimentally observed diffusivity coefficients and those theoretically estimated from geometric theory are also observed. However, the equilibrium swelling of a nanocomposite as indicated by the solubility coefficient did not change. To gain an insight into the solvent interaction behavior, we conducted a pre- and post swollen segmented phase analysis of pure polymers and nanocomposites. We find that in a nanocomposite, the solvent has to interact with a filler altered hard-soft segmented morphology. In the altered phase separated morphology, the spatial distribution of thermodynamically segmented hard blocks in the continuous soft matrix becomes a strong function of filler concentration. Upon solvent interaction, this spatial distribution gets reoriented due to sorption and de-clustering. The results indicate strong non-barrier influences of nanoscale fillers dispersed in phase segmented block co-polymers, affecting solvent diffusivity through them. Based on pre- and post swollen morphological observations, we postulate a possible mechanism for the non-monotonic behaviour of solvent transport for hard-soft segmented co-polymers, in which the thermodynamic phase separation is influenced by the filler.

  2. Brain MRI Segmentation with Multiphase Minimal Partitioning: A Comparative Study

    PubMed Central

    Angelini, Elsa D.; Song, Ting; Mensh, Brett D.; Laine, Andrew F.

    2007-01-01

    This paper presents the implementation and quantitative evaluation of a multiphase three-dimensional deformable model in a level set framework for automated segmentation of brain MRIs. The segmentation algorithm performs an optimal partitioning of three-dimensional data based on homogeneity measures that naturally evolves to the extraction of different tissue types in the brain. Random seed initialization was used to minimize the sensitivity of the method to initial conditions while avoiding the need for a priori information. This random initialization ensures robustness of the method with respect to the initialization and the minimization set up. Postprocessing corrections with morphological operators were applied to refine the details of the global segmentation method. A clinical study was performed on a database of 10 adult brain MRI volumes to compare the level set segmentation to three other methods: “idealized” intensity thresholding, fuzzy connectedness, and an expectation maximization classification using hidden Markov random fields. Quantitative evaluation of segmentation accuracy was performed with comparison to manual segmentation computing true positive and false positive volume fractions. A statistical comparison of the segmentation methods was performed through a Wilcoxon analysis of these error rates and results showed very high quality and stability of the multiphase three-dimensional level set method. PMID:18253474

  3. Microfluidic device and method for focusing, segmenting, and dispensing of a fluid stream

    DOEpatents

    Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN

    2008-09-09

    A microfluidic device and method for forming and dispensing minute volume segments of a material are described. In accordance with the present invention, a microfluidic device and method are provided for spatially confining the material in a focusing element. The device is also adapted for segmenting the confined material into minute volume segments, and dispensing a volume segment to a waste or collection channel. The device further includes means for driving the respective streams of sample and focusing fluids through respective channels into a chamber, such that the focusing fluid streams spatially confine the sample material. The device may also include additional means for driving a minute volume segment of the spatially confined sample material into a collection channel in fluid communication with the waste reservoir.

  4. Microfluidic device and method for focusing, segmenting, and dispensing of a fluid stream

    DOEpatents

    Jacobson, Stephen C.; Ramsey, J. Michael

    2004-09-14

    A microfluidic device for forming and/or dispensing minute volume segments of a material is described. In accordance with one aspect of the present invention, a microfluidic device and method is provided for spatially confining the material in a focusing element. The device is also capable of segmenting the confined material into minute volume segments, and dispensing a volume segment to a waste or collection channel. The device further includes means for driving the respective streams of sample and focusing fluids through respective channels into a chamber, such that the focusing fluid streams spatially confine the sample material. The device may also include additional means for driving a minute volume segment of the spatially confined sample material into a collection channel in fluid communication with the waste reservoir.

  5. Tooth segmentation system with intelligent editing for cephalometric analysis

    NASA Astrophysics Data System (ADS)

    Chen, Shoupu

    2015-03-01

    Cephalometric analysis is the study of the dental and skeletal relationship in the head, and it is used as an assessment and planning tool for improved orthodontic treatment of a patient. Conventional cephalometric analysis identifies bony and soft-tissue landmarks in 2D cephalometric radiographs, in order to diagnose facial features and abnormalities prior to treatment, or to evaluate the progress of treatment. Recent studies in orthodontics indicate that there are persistent inaccuracies and inconsistencies in the results provided using conventional 2D cephalometric analysis. Obviously, plane geometry is inappropriate for analyzing anatomical volumes and their growth; only a 3D analysis is able to analyze the three-dimensional, anatomical maxillofacial complex, which requires computing inertia systems for individual or groups of digitally segmented teeth from an image volume of a patient's head. For the study of 3D cephalometric analysis, the current paper proposes a system for semi-automatically segmenting teeth from a cone beam computed tomography (CBCT) volume with two distinct features, including an intelligent user-input interface for automatic background seed generation, and a graphics processing unit (GPU) acceleration mechanism for three-dimensional GrowCut volume segmentation. Results show a satisfying average DICE score of 0.92, with the use of the proposed tooth segmentation system, by 15 novice users who segmented a randomly sampled tooth set. The average GrowCut processing time is around one second per tooth, excluding user interaction time.

  6. Segmentation of stereo terrain images

    NASA Astrophysics Data System (ADS)

    George, Debra A.; Privitera, Claudio M.; Blackmon, Theodore T.; Zbinden, Eric; Stark, Lawrence W.

    2000-06-01

    We have studied four approaches to segmentation of images: three automatic ones using image processing algorithms and a fourth approach, human manual segmentation. We were motivated toward helping with an important NASA Mars rover mission task -- replacing laborious manual path planning with automatic navigation of the rover on the Mars terrain. The goal of the automatic segmentations was to identify an obstacle map on the Mars terrain to enable automatic path planning for the rover. The automatic segmentation was first explored with two different segmentation methods: one based on pixel luminance, and the other based on pixel altitude generated through stereo image processing. The third automatic segmentation was achieved by combining these two types of image segmentation. Human manual segmentation of Martian terrain images was used for evaluating the effectiveness of the combined automatic segmentation as well as for determining how different humans segment the same images. Comparisons between two different segmentations, manual or automatic, were measured using a similarity metric, SAB. Based on this metric, the combined automatic segmentation did fairly well in agreeing with the manual segmentation. This was a demonstration of a positive step towards automatically creating the accurate obstacle maps necessary for automatic path planning and rover navigation.

  7. Discovery and replication of dopamine-related gene effects on caudate volume in young and elderly populations (N=1198) using genome-wide search

    PubMed Central

    Stein, Jason L.; Hibar, Derrek P.; Madsen, Sarah K.; Khamis, Mathew; McMahon, Katie L.; de Zubicaray, Greig I.; Hansell, Narelle K.; Montgomery, Grant W.; Martin, Nicholas G.; Wright, Margaret J.; Saykin, Andrew J.; Jack, Clifford R.; Weiner, Michael W.; Toga, Arthur W.; Thompson, Paul M.

    2011-01-01

    The caudate is a subcortical brain structure implicated in many common neurological and psychiatric disorders. To identify specific genes associated with variations in caudate volume, structural MRI and genome-wide genotypes were acquired from two large cohorts, the Alzheimer’s Disease NeuroImaging Initiative (ADNI; N=734) and the Brisbane Adolescent/Young Adult Longitudinal Twin Study (BLTS; N=464). In a preliminary analysis of heritability, around 90% of the variation in caudate volume was due to genetic factors. We then conducted genome-wide association to find common variants that contribute to this relatively high heritability. Replicated genetic association was found for the right caudate volume at SNP rs163030 in the ADNI discovery sample (P=2.36×10−6) and in the BLTS replication sample (P=0.012). This genetic variation accounted for 2.79% and 1.61% of the trait variance, respectively. The peak of association was found in and around two genes, WDR41 and PDE8B, involved in dopamine signaling and development. In addition, a previously identified mutation in PDE8B causes a rare autosomal-dominant type of striatal degeneration. Searching across both samples offers a rigorous way to screen for genes consistently influencing brain structure at different stages of life. Variants identified here may be relevant to common disorders affecting the caudate. PMID:21502949

  8. Discovery and replication of dopamine-related gene effects on caudate volume in young and elderly populations (N=1198) using genome-wide search.

    PubMed

    Stein, J L; Hibar, D P; Madsen, S K; Khamis, M; McMahon, K L; de Zubicaray, G I; Hansell, N K; Montgomery, G W; Martin, N G; Wright, M J; Saykin, A J; Jack, C R; Weiner, M W; Toga, A W; Thompson, P M

    2011-09-01

    The caudate is a subcortical brain structure implicated in many common neurological and psychiatric disorders. To identify specific genes associated with variations in caudate volume, structural magnetic resonance imaging and genome-wide genotypes were acquired from two large cohorts, the Alzheimer's Disease NeuroImaging Initiative (ADNI; N=734) and the Brisbane Adolescent/Young Adult Longitudinal Twin Study (BLTS; N=464). In a preliminary analysis of heritability, around 90% of the variation in caudate volume was due to genetic factors. We then conducted genome-wide association to find common variants that contribute to this relatively high heritability. Replicated genetic association was found for the right caudate volume at single-nucleotide polymorphism rs163030 in the ADNI discovery sample (P=2.36 × 10⁻⁶) and in the BLTS replication sample (P=0.012). This genetic variation accounted for 2.79 and 1.61% of the trait variance, respectively. The peak of association was found in and around two genes, WDR41 and PDE8B, involved in dopamine signaling and development. In addition, a previously identified mutation in PDE8B causes a rare autosomal-dominant type of striatal degeneration. Searching across both samples offers a rigorous way to screen for genes consistently influencing brain structure at different stages of life. Variants identified here may be relevant to common disorders affecting the caudate. PMID:21502949

  9. Cerebral magnetic resonance image segmentation using data fusion

    SciTech Connect

    Rajapakse, J.C.; Giedd, J.N.; Krain, A.L.; Hamburger, S.D.; Rapoport, J.L.; DeCarli, C.

    1996-03-01

    A semiautomated method is described for segmenting dual echo MR head scans into gray and white matter and CSF. The method is applied to brain scans of 80 healthy children and adolescents. A probabilistic data fusion equation was used to combine simultaneously acquired T2-weighted and proton density head scans for tissue segmentation. The fusion equation optimizes the probability of a voxel being a particular tissue type, given the corresponding probabilities from both images. The algorithm accounts for the intensity inhomogeneities present in the images by fusion of local regions of the images. The method was validated using a phantom (agarose gel with iron oxide particles) and hand-segmented imager. Gray and white matter volumes for subjects aged 20-30 years were close to those previously published. White matter and CSF volume increased and gray matter volume decreased significantly across ages 4-18 years. White matter, gray matter, and CSF volumes were larger for males than for females. Males and females showed similar change of gray and white matter volumes with age. This simple, reliable, and valid method can be employed in clinical research for quantification of gray and white matter and CSF volumes in MR head scans. Increase in white matter volume may reflect ongoing axonal growth and myelination, and gray matter reductions may reflect synaptic pruning or cell death in the age span of 4-18 years. 41 refs., 5 figs., 3 tabs.

  10. Segmentation and visualization of anatomical structures from volumetric medical images

    NASA Astrophysics Data System (ADS)

    Park, Jonghyun; Park, Soonyoung; Cho, Wanhyun; Kim, Sunworl; Kim, Gisoo; Ahn, Gukdong; Lee, Myungeun; Lim, Junsik

    2011-03-01

    This paper presents a method that can extract and visualize anatomical structures from volumetric medical images by using a 3D level set segmentation method and a hybrid volume rendering technique. First, the segmentation using the level set method was conducted through a surface evolution framework based on the geometric variation principle. This approach addresses the topological changes in the deformable surface by using the geometric integral measures and level set theory. These integral measures contain a robust alignment term, an active region term, and a mean curvature term. By using the level set method with a new hybrid speed function derived from the geometric integral measures, the accurate deformable surface can be extracted from a volumetric medical data set. Second, we employed a hybrid volume rendering approach to visualize the extracted deformable structures. Our method combines indirect and direct volume rendering techniques. Segmented objects within the data set are rendered locally by surface rendering on an object-by-object basis. Globally, all the results of subsequent object rendering are obtained by direct volume rendering (DVR). Then the two rendered results are finally combined in a merging step. This is especially useful when inner structures should be visualized together with semi-transparent outer parts. This merging step is similar to the focus-plus-context approach known from information visualization. Finally, we verified the accuracy and robustness of the proposed segmentation method for various medical volume images. The volume rendering results of segmented 3D objects show that our proposed method can accurately extract and visualize human organs from various multimodality medical volume images.

  11. BIANCA (Brain Intensity AbNormality Classification Algorithm): A new tool for automated segmentation of white matter hyperintensities.

    PubMed

    Griffanti, Ludovica; Zamboni, Giovanna; Khan, Aamira; Li, Linxin; Bonifacio, Guendalina; Sundaresan, Vaanathi; Schulz, Ursula G; Kuker, Wilhelm; Battaglini, Marco; Rothwell, Peter M; Jenkinson, Mark

    2016-11-01

    Reliable quantification of white matter hyperintensities of presumed vascular origin (WMHs) is increasingly needed, given the presence of these MRI findings in patients with several neurological and vascular disorders, as well as in elderly healthy subjects. We present BIANCA (Brain Intensity AbNormality Classification Algorithm), a fully automated, supervised method for WMH detection, based on the k-nearest neighbour (k-NN) algorithm. Relative to previous k-NN based segmentation methods, BIANCA offers different options for weighting the spatial information, local spatial intensity averaging, and different options for the choice of the number and location of the training points. BIANCA is multimodal and highly flexible so that the user can adapt the tool to their protocol and specific needs. We optimised and validated BIANCA on two datasets with different MRI protocols and patient populations (a "predominantly neurodegenerative" and a "predominantly vascular" cohort). BIANCA was first optimised on a subset of images for each dataset in terms of overlap and volumetric agreement with a manually segmented WMH mask. The correlation between the volumes extracted with BIANCA (using the optimised set of options), the volumes extracted from the manual masks and visual ratings showed that BIANCA is a valid alternative to manual segmentation. The optimised set of options was then applied to the whole cohorts and the resulting WMH volume estimates showed good correlations with visual ratings and with age. Finally, we performed a reproducibility test, to evaluate the robustness of BIANCA, and compared BIANCA performance against existing methods. Our findings suggest that BIANCA, which will be freely available as part of the FSL package, is a reliable method for automated WMH segmentation in large cross-sectional cohort studies. PMID:27402600

  12. Functional Segments in Tongue Movement

    ERIC Educational Resources Information Center

    Stone, Maureen; Epstein, Melissa A.; Iskarous, Khalil

    2004-01-01

    The tongue is a deformable object, and moves by compressing or expanding local functional segments. For any single phoneme, these functional tongue segments may move in similar or opposite directions, and may reach target maximum synchronously or not. This paper will discuss the independence of five proposed segments in the production of speech.…

  13. Market Segmentation for Information Services.

    ERIC Educational Resources Information Center

    Halperin, Michael

    1981-01-01

    Discusses the advantages and limitations of market segmentation as strategy for the marketing of information services made available by nonprofit organizations, particularly libraries. Market segmentation is defined, a market grid for libraries is described, and the segmentation of information services is outlined. A 16-item reference list is…

  14. A novel cell segmentation method and cell phase identification using Markov model.

    PubMed

    Zhou, Xiaobo; Li, Fuhai; Yan, Jun; Wong, Stephen T C

    2009-03-01

    Optical microscopy is becoming an important technique in drug discovery and life science research. The approaches used to analyze optical microscopy images are generally classified into two categories: automatic and manual approaches. However, the existing automatic systems are rather limited in dealing with large volume of time-lapse microscopy images because of the complexity of cell behaviors and morphological variance. On the other hand, manual approaches are very time-consuming. In this paper, we propose an effective automated, quantitative analysis system that can be used to segment, track, and quantize cell cycle behaviors of a large population of cells nuclei effectively and efficiently. We use adaptive thresholding and watershed algorithm for cell nuclei segmentation followed by a fragment merging method that combines two scoring models based on trend and no trend features. Using the context information of time-lapse data, the phases of cell nuclei are identified accurately via a Markov model. Experimental results show that the proposed system is effective for nuclei segmentation and phase identification.

  15. Cell segmentation for division rate estimation in computerized video time-lapse microscopy

    NASA Astrophysics Data System (ADS)

    He, Weijun; Wang, Xiaoxu; Metaxas, Dimitris; Mathew, Robin; White, Eileen

    2007-02-01

    The automated estimation of cell division rate plays an important role in the evaluation of a gene function in high throughput biomedical research. Using Computerized Video Time-Lapse (CVTL) microcopy , it is possible to follow a large number of cells in their physiological conditions for several generations. However analysis of this large volume data is complicated due to cell to cell contacts in a high density population. We approach this problem by segmenting out cells or cell clusters through a learning method. The feature of a pixel is represented by the intensity and gradient information in a small surrounding sub-window. Curve evolution techniques are used to accurately find the cell or cell cluster boundary. With the assumption that the average cell size is the same in each frame, we can use the cell area to estimate the cell division rate. Our segmentation results are compared to manually-defined ground truth. Both recall and precision measures for segmentation accuracy are above 95%.

  16. Magnetic resonance brain tissue segmentation based on sparse representations

    NASA Astrophysics Data System (ADS)

    Rueda, Andrea

    2015-12-01

    Segmentation or delineation of specific organs and structures in medical images is an important task in the clinical diagnosis and treatment, since it allows to characterize pathologies through imaging measures (biomarkers). In brain imaging, segmentation of main tissues or specific structures is challenging, due to the anatomic variability and complexity, and the presence of image artifacts (noise, intensity inhomogeneities, partial volume effect). In this paper, an automatic segmentation strategy is proposed, based on sparse representations and coupled dictionaries. Image intensity patterns are singly related to tissue labels at the level of small patches, gathering this information in coupled intensity/segmentation dictionaries. This dictionaries are used within a sparse representation framework to find the projection of a new intensity image onto the intensity dictionary, and the same projection can be used with the segmentation dictionary to estimate the corresponding segmentation. Preliminary results obtained with two publicly available datasets suggest that the proposal is capable of estimating adequate segmentations for gray matter (GM) and white matter (WM) tissues, with an average overlapping of 0:79 for GM and 0:71 for WM (with respect to original segmentations).

  17. Semiautomatic segmentation of liver metastases on volumetric CT images

    SciTech Connect

    Yan, Jiayong; Schwartz, Lawrence H.; Zhao, Binsheng

    2015-11-15

    Purpose: Accurate segmentation and quantification of liver metastases on CT images are critical to surgery/radiation treatment planning and therapy response assessment. To date, there are no reliable methods to perform such segmentation automatically. In this work, the authors present a method for semiautomatic delineation of liver metastases on contrast-enhanced volumetric CT images. Methods: The first step is to manually place a seed region-of-interest (ROI) in the lesion on an image. This ROI will (1) serve as an internal marker and (2) assist in automatically identifying an external marker. With these two markers, lesion contour on the image can be accurately delineated using traditional watershed transformation. Density information will then be extracted from the segmented 2D lesion and help determine the 3D connected object that is a candidate of the lesion volume. The authors have developed a robust strategy to automatically determine internal and external markers for marker-controlled watershed segmentation. By manually placing a seed region-of-interest in the lesion to be delineated on a reference image, the method can automatically determine dual threshold values to approximately separate the lesion from its surrounding structures and refine the thresholds from the segmented lesion for the accurate segmentation of the lesion volume. This method was applied to 69 liver metastases (1.1–10.3 cm in diameter) from a total of 15 patients. An independent radiologist manually delineated all lesions and the resultant lesion volumes served as the “gold standard” for validation of the method’s accuracy. Results: The algorithm received a median overlap, overestimation ratio, and underestimation ratio of 82.3%, 6.0%, and 11.5%, respectively, and a median average boundary distance of 1.2 mm. Conclusions: Preliminary results have shown that volumes of liver metastases on contrast-enhanced CT images can be accurately estimated by a semiautomatic segmentation

  18. Multi-part modeling and segmentation of left atrium in C-arm CT for image-guided ablation of atrial fibrillation.

    PubMed

    Yefeng Zheng; Dong Yang; John, Matthias; Comaniciu, Dorin

    2014-02-01

    As a minimally invasive surgery to treat atrial fibrillation (AF), catheter based ablation uses high radio-frequency energy to eliminate potential sources of abnormal electrical events, especially around the ostia of pulmonary veins (PV). Fusing a patient-specific left atrium (LA) model (including LA chamber, appendage, and PVs) with electro-anatomical maps or overlaying the model onto 2-D real-time fluoroscopic images provides valuable visual guidance during the intervention. In this work, we present a fully automatic LA segmentation system on nongated C-arm computed tomography (C-arm CT) data, where thin boundaries between the LA and surrounding tissues are often blurred due to the cardiac motion artifacts. To avoid segmentation leakage, the shape prior should be exploited to guide the segmentation. A single holistic shape model is often not accurate enough to represent the whole LA shape population under anatomical variations, e.g., the left common PVs vs. separate left PVs. Instead, a part based LA model is proposed, which includes the chamber, appendage, four major PVs, and right middle PVs. Each part is a much simpler anatomical structure compared to the holistic one and can be segmented using a model-based approach (except the right middle PVs). After segmenting the LA parts, the gaps and overlaps among the parts are resolved and segmentation of the ostia region is further refined. As a common anatomical variation, some patients may contain extra right middle PVs, which are segmented using a graph cuts algorithm under the constraints from the already extracted major right PVs. Our approach is computationally efficient, taking about 2.6 s to process a volume with 256 × 256 × 245 voxels. Experiments on 687 C-arm CT datasets demonstrate its robustness and state-of-the-art segmentation accuracy.

  19. Medical anatomy segmentation kit: combining 2D and 3D segmentation methods to enhance functionality

    NASA Astrophysics Data System (ADS)

    Tracton, Gregg S.; Chaney, Edward L.; Rosenman, Julian G.; Pizer, Stephen M.

    1994-07-01

    Image segmentation, in particular, defining normal anatomic structures and diseased or malformed tissue from tomographic images, is common in medical applications. Defining tumors or arterio-venous malformation from computed tomography or magnetic resonance images are typical examples. This paper describes a program, Medical Anatomy Segmentation Kit (MASK), whose design acknowledges that no single segmentation technique has proven to be successful or optimal for all object definition tasks associated with medical images. A practical solution is offered through a suite of complementary user-guided segmentation techniques and extensive manual editing functions to reach the final object definition goal. Manual editing can also be used to define objects which are abstract or otherwise not well represented in the image data and so require direct human definition - e.g., a radiotherapy target volume which requires human knowledge and judgement regarding image interpretation and tumor spread characteristics. Results are either in the form of 2D boundaries or regions of labeled pixels or voxels. MASK currently uses thresholding and edge detection to form contours, and 2D or 3D scale-sensitive fill and region algebra to form regions. In addition to these proven techniques, MASK's architecture anticipates clinically practical automatic 2D and 3D segmentation methods of the future.

  20. Segment lengths influence hill walking strategies.

    PubMed

    Sheehan, Riley C; Gottschall, Jinger S

    2014-08-22

    Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking. PMID:24968942

  1. Optical Ground Segment Performance Summary

    NASA Astrophysics Data System (ADS)

    Breidenthal, J.; Xie, H.; Clare, L.

    2016-05-01

    The performance of candidate optical communication systems for deep space that would use a single optical ground station in conjunction with various space terminals is reported here. We considered three potential diameters of ground receive terminals (4, 8, and 12 m) and three potential ground transmit powers (1, 5, and 10 kW). Combinations of ground receive terminals, ground transmit terminals, and spacecraft terminals were assessed for data rate and volume (both uplink and downlink), and for uplink irradiance needed to enable downlink pointing, in the context of a set of 12 design reference missions. Raw physical link performance was assessed assuming clear weather conditions with conservative desert daytime turbulence, using communication link parameters that were optimized according to previously reported methods using the Strategic Optical Link Tool (SOLT). Also, realistic bad weather conditions were considered, assuming a random process that could at any time make transitions between two states: a cloud-free state and a cloudy state that completely interrupts data transmission. We compared the link performance achievable under our assumptions to the anticipated requirements associated with the design reference missions to determine the degree of satisfaction possible with various optical segments. Nine potential operating concepts for an optical communication system were described, and two were evaluated in detail for the Mars 2022 mission opportunity: raw data delivery and automatic repeat request for complete data delivery.

  2. Anterior Segment Eye Assessment of Refractive Surgery Candidates in the Southeast of Iran.

    PubMed

    Nakhjavanpour, Neda; Payandeh, Abolfazl; Rajabi, Majid; Shoja, Vahid

    2016-01-01

    Anterior segment eye parameters are essential factors in diagnosis, screening and management of abnormal ocular conditions. Based on the previous studies, they might differ from one race or population to another. Sistan-and-Baluchestan province, the southeast of Iran, has special weather conditions and race, plus lack of research on these diagnostic factors. Hence, the objective of the present study was to assess anterior segment parameters using pentacam in this area. 800 eyes of subjects which had been referred to the Al-Zahra eye hospital of Zahedan, the capital city of the province, for corneal refractive surgery from October 2014 to March 2015 participated in this research. 95% confidence limits for mean of central corneal thickness, anterior chamber depth and volume were (536.02, 541.20), (3.13, 3.18) and (187.63, 192.58) respectively. Multiple linear regression models showed a lower mean central corneal thickness, and maximum/minimum of keratometry, for males than females, adjusting for age and spherical equivalent. Inversely, anterior chamber depth, and volume were more in males. In order to diagnosis and treating ocular diseases which have effect on retinal thickness, precisely specification of predictive factors is highly needed. PMID:27357884

  3. Segmenting nonenhancing brain tumors from normal tissues in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Fletcher-Heath, Lynn M.; Hall, Lawrence O.; Goldgof, Dmitry B.

    1998-06-01

    Tumor segmentation from magnetic resonance (MR) images aids in tumor treatment by tracking the progress of tumor growth and/or shrinkage. In this paper we present an automatic segmentation method which separates non-enhancing brain tumors from healthy tissues in MR images. The MR feature images used for the segmentation consist of three weighted images (T1, T2 and proton density) for each axial slice through the head. An initial segmentation is computed using an unsupervised clustering algorithm. Then, integrated domain knowledge and image processing techniques contribute to the final tumor segmentation. The system was trained on two patient volumes and preliminary testing has shown successful tumor segmentations on four patient volumes.

  4. Remedial Sheets for Progress Checks, Segments 19-40.

    ERIC Educational Resources Information Center

    New York Inst. of Tech., Old Westbury.

    The second part of the Self-Paced Physics Course remediation materials is presented for U. S. Naval Academy students who miss core problems on the progress check. The total of 101 problems is incorporated in this volume to match study segments 19 through 40. Each remedial sheet is composed of a statement of the missed problem and references to…

  5. Remedial Sheets for Progress Checks, Segments 1-14.

    ERIC Educational Resources Information Center

    New York Inst. of Tech., Old Westbury.

    The first part of the Self-Paced Physics Course remediation materials is presented for U. S. Naval Academy students who miss core problems on the progress check. The total of 78 problems is incorporated in this volume to match study segments 1 through 14. Each remedial sheet is composed of a statement of the missed problem and references to…

  6. LANDSAT-D flight segment operations manual, volume 2

    NASA Technical Reports Server (NTRS)

    Varhola, J.

    1981-01-01

    Functions, performance capabilities, modes of operation, constraints, redundancy, commands, and telemetry are described for the thematic mapper; the global positioning system; the direct access S-band; the multispectral scanner; the payload correction; the thermal control subsystem; the solar array retention, deployment, and jettison assembly; and the boom antenna retention, deployment, and jettison assembly for LANDSAT 4.

  7. LANDSAT-D flight segment operations manual, volume 1

    NASA Technical Reports Server (NTRS)

    Varhola, J.

    1982-01-01

    Hardware, systems, and subsystems for the multimission modular spacecraft used for LANDSAT 4 are described and depicted in block diagrams and schematics. Components discussed include the modular attitude control system; the communication and data handling subsystem; the narrowband tape recorder; the on-board computer; the propulsion module subsystem; the signal conditioning and control unit; the modular power subsystem; the solar array drive and power transmission assembly; the power distribution unit; the digital processing unit; and the wideband communication subsystem.

  8. Topologically correct cortical segmentation using Khalimsky's cubic complex framework

    NASA Astrophysics Data System (ADS)

    Cardoso, Manuel J.; Clarkson, Matthew J.; Modat, Marc; Talbot, Hugues; Couprie, Michel; Ourselin, Sébastien

    2011-03-01

    Automatic segmentation of the cerebral cortex from magnetic resonance brain images is a valuable tool for neuroscience research. Due to the presence of noise, intensity non-uniformity, partial volume effects, the limited resolution of MRI and the highly convoluted shape of the cerebral cortex, segmenting the brain in a robust, accurate and topologically correct way still poses a challenge. In this paper we describe a topologically correct Expectation Maximisation based Maximum a Posteriori segmentation algorithm formulated within the Khalimsky cubic complex framework, where both the solution of the EM algorithm and the information derived from a geodesic distance function are used to locally modify the weighting of a Markov Random Field and drive the topology correction operations. Experiments performed on 20 Brainweb datasets show that the proposed method obtains a topologically correct segmentation without significant loss in accuracy when compared to two well established techniques.

  9. Segmentation method for in vivo meibomian gland OCT image

    NASA Astrophysics Data System (ADS)

    Shin, Jun Geun; Lee, Byeong Ha; Eom, Tae Joong

    2014-02-01

    We demonstrate segmentation of human MGs based on several image processing technic. 3D volumetric data of upper eyelid was acquired from real-time FD-OCT, and its acini area of MGs was segmented. Three dimensional volume informations of meibomian glands should be helpful to diagnose meibomian gland related disease. In order to reveal boundary between tarsal plate and acini, each B-scan images were obtained before averaged three times. Imaging area was 10x10mm and 700x1000x500 voxels. The acquisition time was 60ms for B-scan and 30sec for C-scan. The 3D data was flattened to remove curvature and axial vibration, and resized to reduce computational costs, and filtered to minimize speckles, and segmented. Marker based watershed transform was employed to segment each acini area of meibomian gland.

  10. Image segmentation using random features

    NASA Astrophysics Data System (ADS)

    Bull, Geoff; Gao, Junbin; Antolovich, Michael

    2014-01-01

    This paper presents a novel algorithm for selecting random features via compressed sensing to improve the performance of Normalized Cuts in image segmentation. Normalized Cuts is a clustering algorithm that has been widely applied to segmenting images, using features such as brightness, intervening contours and Gabor filter responses. Some drawbacks of Normalized Cuts are that computation times and memory usage can be excessive, and the obtained segmentations are often poor. This paper addresses the need to improve the processing time of Normalized Cuts while improving the segmentations. A significant proportion of the time in calculating Normalized Cuts is spent computing an affinity matrix. A new algorithm has been developed that selects random features using compressed sensing techniques to reduce the computation needed for the affinity matrix. The new algorithm, when compared to the standard implementation of Normalized Cuts for segmenting images from the BSDS500, produces better segmentations in significantly less time.

  11. Optimal retinal cyst segmentation from OCT images

    NASA Astrophysics Data System (ADS)

    Oguz, Ipek; Zhang, Li; Abramoff, Michael D.; Sonka, Milan

    2016-03-01

    Accurate and reproducible segmentation of cysts and fluid-filled regions from retinal OCT images is an important step allowing quantification of the disease status, longitudinal disease progression, and response to therapy in wet-pathology retinal diseases. However, segmentation of fluid-filled regions from OCT images is a challenging task due to their inhomogeneous appearance, the unpredictability of their number, size and location, as well as the intensity profile similarity between such regions and certain healthy tissue types. While machine learning techniques can be beneficial for this task, they require large training datasets and are often over-fitted to the appearance models of specific scanner vendors. We propose a knowledge-based approach that leverages a carefully designed cost function and graph-based segmentation techniques to provide a vendor-independent solution to this problem. We illustrate the results of this approach on two publicly available datasets with a variety of scanner vendors and retinal disease status. Compared to a previous machine-learning based approach, the volume similarity error was dramatically reduced from 81:3+/-56:4% to 22:2+/-21:3% (paired t-test, p << 0:001).

  12. Automated 3D ultrasound image segmentation to aid breast cancer image interpretation.

    PubMed

    Gu, Peng; Lee, Won-Mean; Roubidoux, Marilyn A; Yuan, Jie; Wang, Xueding; Carson, Paul L

    2016-02-01

    Segmentation of an ultrasound image into functional tissues is of great importance to clinical diagnosis of breast cancer. However, many studies are found to segment only the mass of interest and not all major tissues. Differences and inconsistencies in ultrasound interpretation call for an automated segmentation method to make results operator-independent. Furthermore, manual segmentation of entire three-dimensional (3D) ultrasound volumes is time-consuming, resource-intensive, and clinically impractical. Here, we propose an automated algorithm to segment 3D ultrasound volumes into three major tissue types: cyst/mass, fatty tissue, and fibro-glandular tissue. To test its efficacy and consistency, the proposed automated method was employed on a database of 21 cases of whole breast ultrasound. Experimental results show that our proposed method not only distinguishes fat and non-fat tissues correctly, but performs well in classifying cyst/mass. Comparison of density assessment between the automated method and manual segmentation demonstrates good consistency with an accuracy of 85.7%. Quantitative comparison of corresponding tissue volumes, which uses overlap ratio, gives an average similarity of 74.54%, consistent with values seen in MRI brain segmentations. Thus, our proposed method exhibits great potential as an automated approach to segment 3D whole breast ultrasound volumes into functionally distinct tissues that may help to correct ultrasound speed of sound aberrations and assist in density based prognosis of breast cancer.

  13. Automated 3D ultrasound image segmentation for assistant diagnosis of breast cancer

    NASA Astrophysics Data System (ADS)

    Wang, Yuxin; Gu, Peng; Lee, Won-Mean; Roubidoux, Marilyn A.; Du, Sidan; Yuan, Jie; Wang, Xueding; Carson, Paul L.

    2016-04-01

    Segmentation of an ultrasound image into functional tissues is of great importance to clinical diagnosis of breast cancer. However, many studies are found to segment only the mass of interest and not all major tissues. Differences and inconsistencies in ultrasound interpretation call for an automated segmentation method to make results operator-independent. Furthermore, manual segmentation of entire three-dimensional (3D) ultrasound volumes is time-consuming, resource-intensive, and clinically impractical. Here, we propose an automated algorithm to segment 3D ultrasound volumes into three major tissue types: cyst/mass, fatty tissue, and fibro-glandular tissue. To test its efficacy and consistency, the proposed automated method was employed on a database of 21 cases of whole breast ultrasound. Experimental results show that our proposed method not only distinguishes fat and non-fat tissues correctly, but performs well in classifying cyst/mass. Comparison of density assessment between the automated method and manual segmentation demonstrates good consistency with an accuracy of 85.7%. Quantitative comparison of corresponding tissue volumes, which uses overlap ratio, gives an average similarity of 74.54%, consistent with values seen in MRI brain segmentations. Thus, our proposed method exhibits great potential as an automated approach to segment 3D whole breast ultrasound volumes into functionally distinct tissues that may help to correct ultrasound speed of sound aberrations and assist in density based prognosis of breast cancer.

  14. MRI brain tumor segmentation and necrosis detection using adaptive Sobolev snakes

    NASA Astrophysics Data System (ADS)

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-03-01

    Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at di erent points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D di usion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation.

  15. Segmented heat exchanger

    DOEpatents

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  16. Bone image segmentation.

    PubMed

    Liu, Z Q; Liew, H L; Clement, J G; Thomas, C D

    1999-05-01

    Characteristics of microscopic structures in bone cross sections carry essential clues in age determination in forensic science and in the study of age-related bone developments and bone diseases. Analysis of bone cross sections represents a major area of research in bone biology. However, traditional approaches in bone biology have relied primarily on manual processes with very limited number of bone samples. As a consequence, it is difficult to reach reliable and consistent conclusions. In this paper we present an image processing system that uses microstructural and relational knowledge present in the bone cross section for bone image segmentation. This system automates the bone image analysis process and is able to produce reliable results based on quantitative measurements from a large number of bone images. As a result, using large databases of bone images to study the correlation between bone structural features and age-related bone developments becomes feasible.

  17. Probabilistic retinal vessel segmentation

    NASA Astrophysics Data System (ADS)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  18. Partially segmented deformable mirror

    DOEpatents

    Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

    1991-05-21

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

  19. Partially segmented deformable mirror

    DOEpatents

    Bliss, Erlan S.; Smith, James R.; Salmon, J. Thaddeus; Monjes, Julio A.

    1991-01-01

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

  20. Multiple-Segment Climbing Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James; May, Edward; Eklund, Wayne

    1994-01-01

    Multiple-segment climbing robots developed to perform such tasks as inspection, sandblasting, welding, and painting on towers and other structures. Look and move like caterpillars. Video camera mounted on one of segments rotated to desired viewing angle. Used in remote inspection of structure, to view motion of robot and/or provides video feedback for control of motion, and/or to guide operation of head mounted on foremost segment with motorized actuators.

  1. Segmented rail linear induction motor

    DOEpatents

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  2. Segmented rail linear induction motor

    DOEpatents

    Cowan, M. Jr.; Marder, B.M.

    1996-09-03

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.

  3. Usefulness of texture features for segmentation of lungs with severe diffuse interstitial lung disease

    NASA Astrophysics Data System (ADS)

    Wang, Jiahui; Li, Feng; Li, Qiang

    2010-03-01

    We developed an automated method for the segmentation of lungs with severe diffuse interstitial lung disease (DILD) in multi-detector CT. In this study, we would like to compare the performance levels of this method and a thresholdingbased segmentation method for normal lungs, moderately abnormal lungs, severely abnormal lungs, and all lungs in our database. Our database includes 31 normal cases and 45 abnormal cases with severe DILD. The outlines of lungs were manually delineated by a medical physicist and confirmed by an experienced chest radiologist. These outlines were used as reference standards for the evaluation of the segmentation results. We first employed a thresholding technique for CT value to obtain initial lungs, which contain normal and mildly abnormal lung parenchyma. We then used texture-feature images derived from co-occurrence matrix to further segment lung regions with severe DILD. The segmented lung regions with severe DILD were combined with the initial lungs to generate the final segmentation results. We also identified and removed the airways to improve the accuracy of the segmentation results. We used three metrics, i.e., overlap, volume agreement, and mean absolute distance (MAD) between automatically segmented lung and reference lung to evaluate the performance of our segmentation method and the thresholding-based segmentation method. Our segmentation method achieved a mean overlap of 96.1%, a mean volume agreement of 98.1%, and a mean MAD of 0.96 mm for the 45 abnormal cases. On the other hand the thresholding-based segmentation method achieved a mean overlap of 94.2%, a mean volume agreement of 95.8%, and a mean MAD of 1.51 mm for the 45 abnormal cases. Our new method obtained higher performance level than the thresholding-based segmentation method.

  4. Characterizing and Reaching High-Risk Drinkers Using Audience Segmentation

    PubMed Central

    Moss, Howard B.; Kirby, Susan D.; Donodeo, Fred

    2010-01-01

    Background Market or audience segmentation is widely used in social marketing efforts to help planners identify segments of a population to target for tailored program interventions. Market-based segments are typically defined by behaviors, attitudes, knowledge, opinions, or lifestyles. They are more helpful to health communication and marketing planning than epidemiologically-defined groups because market-based segments are similar in respect to how they behave or might react to marketing and communication efforts. However, market segmentation has rarely been used in alcohol research. As an illustration of its utility, we employed commercial data that describes the sociodemographic characteristics of high-risk drinkers as an audience segment; where they tend to live, lifestyles, interests, consumer behaviors, alcohol consumption behaviors, other health-related behaviors, and cultural values. Such information can be extremely valuable in targeting and planning public health campaigns, targeted mailings, prevention interventions and research efforts. Methods We describe the results of a segmentation analysis of those individuals who self-report consuming five or more drinks per drinking episode at least twice in the last 30-days. The study used the proprietary PRIZM™ audience segmentation database merged with Center for Disease Control and Prevention's (CDC) Behavioral Risk Factor Surveillance System (BRFSS) database. The top ten of the 66 PRIZM™ audience segments for this risky drinking pattern are described. For five of these segments we provide additional in-depth details about consumer behavior and the estimates of the market areas where these risky drinkers reside. Results The top ten audience segments (PRIZM clusters) most likely to engage in high-risk drinking are described. The cluster with the highest concentration of binge drinking behavior is referred to as the “Cyber Millenials.” This cluster is characterized as “the nation's tech-savvy singles

  5. Asteroid Redirect Mission: Robotic Segment

    NASA Video Gallery

    This concept animation illustrates the robotic segment of NASA's Asteroid Redirect Mission. The Asteroid Redirect Vehicle, powered by solar electric propulsion, travels to a large asteroid to robot...

  6. Free Prostate-Specific Antigen Provides More Precise Data on Benign Prostate Volume Than Total Prostate-Specific Antigen in Korean Population

    PubMed Central

    Choi, Hoon; Park, Jae Young; Shim, Ji Sung; Kim, Jae Heon

    2013-01-01

    Purpose To investigate the efficacy of total prostate-specific antigen (tPSA) and free prostate-specific antigen (fPSA) for the estimation of prostate volume (PV) in pathologically-proven benign prostatic hyperplasia (BPH) patients. Methods From January 2010 to March 2013, 165 Korean men with a PSA less than 10 ng/mL who were diagnosed without prostate cancer by prostate biopsy were enrolled. Patients were classified into three age groups: ≤60, 61-70, and >70 years old. The results were organized to estimate and compare the ability of serum tPSA and fPSA to assess the PV. Results Enrolled patients had a median age of 63.5 years (44 to 80), a median tPSA of 5.72 ng/mL, a median fPSA of 0.98 ng/mL and a median PV of 53.68 mL, respectively. Among the associations between tPSA, fPSA, age, and PV, the highest correlation was verified between fPSA and PV (r=0.377, P<0.0001); the correlation coefficient between tPSA and PV was much lower (r=0.262, P<0.001). All stratified age cohorts showed the same findings. The ROC curves (for PV greater than 30, 40, and 50 mL) showed that fPSA (area under the curve [AUC]=0.781, 0.718, and 0.700) outperformed tPSA (AUC=0.657, 0.583, and 0.67) in its ability to predict clinically significant PV enlargement. Conclusion Both tPSA and fPSA significantly correlated with PV in Korean men, while the correlation efficiency between fPSA and PV was more powerful. fPSA may be a useful tool in making therapeutic decisions and follow-up management in BPH patients. PMID:23869271

  7. Segmenting Words from Natural Speech: Subsegmental Variation in Segmental Cues

    ERIC Educational Resources Information Center

    Rytting, C. Anton; Brew, Chris; Fosler-Lussier, Eric

    2010-01-01

    Most computational models of word segmentation are trained and tested on transcripts of speech, rather than the speech itself, and assume that speech is converted into a sequence of symbols prior to word segmentation. We present a way of representing speech corpora that avoids this assumption, and preserves acoustic variation present in speech. We…

  8. Tomographic segmentation in multiphase flow measurement

    NASA Astrophysics Data System (ADS)

    Sætre, Camilla; Tjugum, Stein-Arild; Anton Johansen, Geir

    2014-02-01

    Measurement of multiphase pipe flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain. These are related to reducing measurement uncertainties arising from variations in the flow regime and the fluid properties, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. In this work the pipe flow is split into temporal segments using multiple gamma-ray measurements. One 241Am source with principal emission at 59.5 keV was used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as use of compact detectors. One detector is placed diametrically opposite the source whereas the second and eventually the third are positioned to the sides so that these beams are close to the pipe wall. The principle is then straight forward, that is to compare the measured intensities of these detectors, and through those identify the instantaneous cross sectional gas-liquid distribution, i.e. the instantaneous flow pattern. By counting the intensity in short time slots of <100 ms, experiments verify that rapid variations exist. The water salinity is one of the fluid properties which challenge most multiphase flow meters because its variations affects component volume fraction calculations based on gamma-ray, electrical conductance and other measurements methods. At the University of Bergen a dual modality method has been developed using simultaneous measurements of transmitted and scattered gamma-rays from a 241Am source. This allows the gas volume fraction to be determined independent of changes in the water salinity, provided that the fluid is fairly homogeneously mixed. Tomographic flow segmentation allows selection of low gas fraction segments where the salinity, in combination with running averaging methods, can be calculated with higher accuracy.

  9. Subcortical brain segmentation of two dimensional T1-weighted data sets with FMRIB's Integrated Registration and Segmentation Tool (FIRST).

    PubMed

    Amann, Michael; Andělová, Michaela; Pfister, Armanda; Mueller-Lenke, Nicole; Traud, Stefan; Reinhardt, Julia; Magon, Stefano; Bendfeldt, Kerstin; Kappos, Ludwig; Radue, Ernst-Wilhelm; Stippich, Christoph; Sprenger, Till

    2015-01-01

    Brain atrophy has been identified as an important contributing factor to the development of disability in multiple sclerosis (MS). In this respect, more and more interest is focussing on the role of deep grey matter (DGM) areas. Novel data analysis pipelines are available for the automatic segmentation of DGM using three-dimensional (3D) MRI data. However, in clinical trials, often no such high-resolution data are acquired and hence no conclusions regarding the impact of new treatments on DGM atrophy were possible so far. In this work, we used FMRIB's Integrated Registration and Segmentation Tool (FIRST) to evaluate the possibility of segmenting DGM structures using standard two-dimensional (2D) T1-weighted MRI. In a cohort of 70 MS patients, both 2D and 3D T1-weighted data were acquired. The thalamus, putamen, pallidum, nucleus accumbens, and caudate nucleus were bilaterally segmented using FIRST. Volumes were calculated for each structure and for the sum of basal ganglia (BG) as well as for the total DGM. The accuracy and reliability of the 2D data segmentation were compared with the respective results of 3D segmentations using volume difference, volume overlap and intra-class correlation coefficients (ICCs). The mean differences for the individual substructures were between 1.3% (putamen) and -25.2% (nucleus accumbens). The respective values for the BG were -2.7% and for DGM 1.3%. Mean volume overlap was between 89.1% (thalamus) and 61.5% (nucleus accumbens); BG: 84.1%; DGM: 86.3%. Regarding ICC, all structures showed good agreement with the exception of the nucleus accumbens. The results of the segmentation were additionally validated through expert manual delineation of the caudate nucleus and putamen in a subset of the 3D data. In conclusion, we demonstrate that subcortical segmentation of 2D data are feasible using FIRST. The larger subcortical GM structures can be segmented with high consistency. This forms the basis for the application of FIRST in large 2D

  10. A Generative Model for Image Segmentation Based on Label Fusion

    PubMed Central

    Thomas Yeo, B. T.; Van Leemput, Koen; Fischl, Bruce; Golland, Polina

    2012-01-01

    We propose a nonparametric, probabilistic model for the automatic segmentation of medical images, given a training set of images and corresponding label maps. The resulting inference algorithms rely on pairwise registrations between the test image and individual training images. The training labels are then transferred to the test image and fused to compute the final segmentation of the test subject. Such label fusion methods have been shown to yield accurate segmentation, since the use of multiple registrations captures greater inter-subject anatomical variability and improves robustness against occasional registration failures. To the best of our knowledge, this manuscript presents the first comprehensive probabilistic framework that rigorously motivates label fusion as a segmentation approach. The proposed framework allows us to compare different label fusion algorithms theoretically and practically. In particular, recent label fusion or multiatlas segmentation algorithms are interpreted as special cases of our framework. We conduct two sets of experiments to validate the proposed methods. In the first set of experiments, we use 39 brain MRI scans—with manually segmented white matter, cerebral cortex, ventricles and subcortical structures—to compare different label fusion algorithms and the widely-used FreeSurfer whole-brain segmentation tool. Our results indicate that the proposed framework yields more accurate segmentation than FreeSurfer and previous label fusion algorithms. In a second experiment, we use brain MRI scans of 282 subjects to demonstrate that the proposed segmentation tool is sufficiently sensitive to robustly detect hippocampal volume changes in a study of aging and Alzheimer’s Disease. PMID:20562040

  11. Comparison of automated and manual segmentation of hippocampus MR images

    NASA Astrophysics Data System (ADS)

    Haller, John W.; Christensen, Gary E.; Miller, Michael I.; Joshi, Sarang C.; Gado, Mokhtar; Csernansky, John G.; Vannier, Michael W.

    1995-05-01

    The precision and accuracy of area estimates from magnetic resonance (MR) brain images and using manual and automated segmentation methods are determined. Areas of the human hippocampus were measured to compare a new automatic method of segmentation with regions of interest drawn by an expert. MR images of nine normal subjects and nine schizophrenic patients were acquired with a 1.5-T unit (Siemens Medical Systems, Inc., Iselin, New Jersey). From each individual MPRAGE 3D volume image a single comparable 2-D slice (matrix equals 256 X 256) was chosen which corresponds to the same coronal slice of the hippocampus. The hippocampus was first manually segmented, then segmented using high dimensional transformations of a digital brain atlas to individual brain MR images. The repeatability of a trained rater was assessed by comparing two measurements from each individual subject. Variability was also compared within and between subject groups of schizophrenics and normal subjects. Finally, the precision and accuracy of automated segmentation of hippocampal areas were determined by comparing automated measurements to manual segmentation measurements made by the trained rater on MR and brain slice images. The results demonstrate the high repeatability of area measurement from MR images of the human hippocampus. Automated segmentation using high dimensional transformations from a digital brain atlas provides repeatability superior to that of manual segmentation. Furthermore, the validity of automated measurements was demonstrated by a high correlation with manual segmentation measurements made by a trained rater. Quantitative morphometry of brain substructures (e.g. hippocampus) is feasible by use of a high dimensional transformation of a digital brain atlas to an individual MR image. This method automates the search for neuromorphological correlates of schizophrenia by a new mathematically robust method with unprecedented sensitivity to small local and regional differences.

  12. Cerebral cortex: an MRI-based study of volume and variance with age and sex.

    PubMed

    Carne, Ross P; Vogrin, Simon; Litewka, Lucas; Cook, Mark J

    2006-01-01

    The aim of the present study was to examine quantitative differences in lobar cerebral cortical volumes in a healthy adult population. Quantitative volumetric MRI of whole brain, cerebral and cerebellar volumes was performed in a cross-sectional analysis of 97 normal volunteers, with segmented frontal, temporal, parietal and occipital cortical volumes measured in a subgroup of 60 subjects, 30 male and 30 female, matched for age and sex. The right cerebral hemisphere was larger than the left across the study group with a small (<1%) but significant difference in symmetry (P<0.001). No difference was found between volumes of right and left cerebellar hemispheres. Rightward cerebral cortical asymmetry (right larger than left) was found to be significant across all lobes except parietal. Males had greater cerebral, cerebellar and cerebral cortical lobar volumes than females. Larger male cerebral cortical volumes were seen in all lobes except for left parietal. Females had greater left parietal to left cerebral hemisphere and smaller left temporal to left cerebral hemisphere ratios. There was a mild reduction in cerebral volumes with age, more marked in males. This study confirms and augments past work indicating underlying structural asymmetries in the human brain, and provides further evidence that brain structures in humans are differentially sensitive to the effects of both age and sex.

  13. Heterogeneous pumice populations in the 2.08-Ma Cerro Galán Ignimbrite: Implications for magma recharge and ascent preceding a large-volume silicic eruption

    USGS Publications Warehouse

    Wright, Heather M.; Folkes, Christopher B.; Cas, Ray A.F.; Cashman, Katharine V.

    2011-01-01

    Triggering mechanisms of large silicic eruptions remain a critical unsolved problem. We address this question for the ~2.08-Ma caldera-forming eruption of Cerro Galán volcano, Argentina, which produced distinct pumice populations of two colors: grey (5%) and white (95%) that we believe may hold clues to the onset of eruptive activity. We demonstrate that the color variations correspond to both textural and compositional variations between the clast types. Both pumice types have bulk compositions of high-K, high-silica dacite to low-silica rhyolite, but there are sufficient compositional differences (e.g., ~150 ppm lower Ba at equivalent SiO2 content and 0.03 wt.% higher TiO2 in white pumice than grey) to suggest that the two pumice populations are not related by simple fractionation. Trace element concentrations in crystals mimic bulk variations between clast types, with grey pumice containing elevated Ba, Cu, Pb, and Zn concentrations in both bulk samples (average Cu, Pb, and Zn concentrations are 27, 35, and 82 in grey pumice vs. 11, 19, and 60 in white pumice) and biotite phenocrysts and white pumice showing elevated Li concentrations in biotite and plagioclase phenocrysts. White and grey clasts are also texturally distinct: White pumice clasts contain abundant phenocrysts (44–57%), lack microlites, and have highly evolved groundmass glass compositions (76.4–79.6 wt.% SiO2), whereas grey pumice clasts contain a lower percentage of phenocrysts/microphenocrysts (35–49%), have abundant microlites, and have less evolved groundmass glass compositions (69.4–73.8 wt.% SiO2). There is also evidence for crystal transfer between magma producing white and grey pumice. Thin highly evolved melt rims surround some fragmental crystals in grey pumice clasts and appear to have come from magma that produced white pumice. Furthermore, based on crystal compositions, white bands within banded pumice contain crystals originating in grey magma. Finally, only grey

  14. The local segmental dynamics of polymer thin films

    NASA Astrophysics Data System (ADS)

    Roland, C. M.; Casalini, Riccardo; Prevosto, Daniele; Labardi, Massimiliano; Zhu, Lei; Baer, Eric

    The local segmental dynamics of poly(methyl methacrylate) (PMMA) in multi-layered films with polycarbonate was investigated using dielectric spectroscopy. The segmental relaxation time decreased with layer thickness down to 4 nm. However, two measures of the cooperativity of the dynamics, the breadth of the relaxation dispersion and the dynamic correlation volume, were unaffected by the film thickness. This absence of an effect of geometric confinement on the cooperativity, even when the confinement length scale approaches the correlation length scale, requires an asymmetric correlation volume; i.e., correlating regions having a string-like nature. To further probe the effect of layering on the segmental dynamics, we measured the segmental dynamics of poly(vinylacetate) thin films in contact with variously an aluminum interface, an incompatible polymer, and air (free surface). From local dielectric relaxation measurements using an AFM tip, the dynamics were observed to be faster in all thin film configurations compared to the bulk. However, no differences were observed for the various interfaces; capping the thin films with a rigid material accelerated the segmental motions equivalently to that for an air interface. This insensitivity of the dynamics to the nature of the interface affords a means to engineer thin films while maintaining desired mechanical properties. Work at NRL supported by the Office of Naval Research.

  15. Segmentation: Slicing the Urban Pie.

    ERIC Educational Resources Information Center

    Keim, William A.

    1981-01-01

    Explains market segmentation and defines undifferentiated, concentrated, and differentiated marketing strategies. Describes in detail the marketing planning process at the Metropolitan Community Colleges. Focuses on the development and implementation of an ongoing recruitment program designed for the market segment composed of business employees.…

  16. The Importance of Marketing Segmentation

    ERIC Educational Resources Information Center

    Martin, Gillian

    2011-01-01

    The rationale behind marketing segmentation is to allow businesses to focus on their consumers' behaviors and purchasing patterns. If done effectively, marketing segmentation allows an organization to achieve its highest return on investment (ROI) in turn for its marketing and sales expenses. If an organization markets its products or services to…

  17. Market Segmentation: An Instructional Module.

    ERIC Educational Resources Information Center

    Wright, Peter H.

    A concept-based introduction to market segmentation is provided in this instructional module for undergraduate and graduate transportation-related courses. The material can be used in many disciplines including engineering, business, marketing, and technology. The concept of market segmentation is primarily a transportation planning technique by…

  18. Optimal segmentation and packaging process

    DOEpatents

    Kostelnik, Kevin M.; Meservey, Richard H.; Landon, Mark D.

    1999-01-01

    A process for improving packaging efficiency uses three dimensional, computer simulated models with various optimization algorithms to determine the optimal segmentation process and packaging configurations based on constraints including container limitations. The present invention is applied to a process for decontaminating, decommissioning (D&D), and remediating a nuclear facility involving the segmentation and packaging of contaminated items in waste containers in order to minimize the number of cuts, maximize packaging density, and reduce worker radiation exposure. A three-dimensional, computer simulated, facility model of the contaminated items are created. The contaminated items are differentiated. The optimal location, orientation and sequence of the segmentation and packaging of the contaminated items is determined using the simulated model, the algorithms, and various constraints including container limitations. The cut locations and orientations are transposed to the simulated model. The contaminated items are actually segmented and packaged. The segmentation and packaging may be simulated beforehand. In addition, the contaminated items may be cataloged and recorded.

  19. Solvent transport through hard-soft segmented polymer nanocomposites.

    PubMed

    Rath, Sangram K; Edatholath, Saji S; Patro, T Umasankar; Sudarshan, Kathi; Sastry, P U; Pujari, Pradeep K; Harikrishnan, G

    2016-01-28

    We conducted transport studies of a common solvent (toluene) in its condensed state, through a model hard-soft segmented polyurethane-clay nanocomposite. The solvent diffusivity is observed to be non-monotonic in a functional relationship with a filler volume fraction. In stark contrast, both classical tortuous path theory based geometric calculations and free volume measurements suggest the normally expected monotonic decrease in diffusivity with increase in clay volume fraction. Large deviations between experimentally observed diffusivity coefficients and those theoretically estimated from geometric theory are also observed. However, the equilibrium swelling of a nanocomposite as indicated by the solubility coefficient did not change. To gain an insight into the solvent interaction behavior, we conducted a pre- and post swollen segmented phase analysis of pure polymers and nanocomposites. We find that in a nanocomposite, the solvent has to interact with a filler altered hard-soft segmented morphology. In the altered phase separated morphology, the spatial distribution of thermodynamically segmented hard blocks in the continuous soft matrix becomes a strong function of filler concentration. Upon solvent interaction, this spatial distribution gets reoriented due to sorption and de-clustering. The results indicate strong non-barrier influences of nanoscale fillers dispersed in phase segmented block co-polymers, affecting solvent diffusivity through them. Based on pre- and post swollen morphological observations, we postulate a possible mechanism for the non-monotonic behaviour of solvent transport for hard-soft segmented co-polymers, in which the thermodynamic phase separation is influenced by the filler. PMID:26726752

  20. Segmental portal hypertension.

    PubMed Central

    Madsen, M S; Petersen, T H; Sommer, H

    1986-01-01

    Isolated obstruction of the splenic vein leads to segmental portal hypertension, which is a rare form of extrahepatic portal hypertension, but it is important to diagnose, since it can be cured by splenectomy. In a review of the English literature, 209 patients with isolated splenic vein obstruction were found. Pancreatitis caused 65% of the cases and pancreatic neoplasms 18%, whereas the rest was caused by various other diseases. Seventy-two per cent of the patients bled from gastroesophageal varices, and most often the bleeding came from isolated gastric varices. The spleen was enlarged in 71% of the patients. A correct diagnosis in connection with the first episode of bleeding was made in only 49%; 22% were operated on because of gastrointestinal bleeding, but the cause of bleeding was not found. The diagnosis should be suspected in patients with gastroesophageal varices, but without signs of a liver disease, especially if isolated gastric varices are found. The diagnosis is confirmed by portography. Images FIG. 1. FIG. 2. PMID:3729585

  1. Easy-interactive and quick psoriasis lesion segmentation

    NASA Astrophysics Data System (ADS)

    Ma, Guoli; He, Bei; Yang, Wenming; Shu, Chang

    2013-12-01

    This paper proposes an interactive psoriasis lesion segmentation algorithm based on Gaussian Mixture Model (GMM). Psoriasis is an incurable skin disease and affects large population in the world. PASI (Psoriasis Area and Severity Index) is the gold standard utilized by dermatologists to monitor the severity of psoriasis. Computer aid methods of calculating PASI are more objective and accurate than human visual assessment. Psoriasis lesion segmentation is the basis of the whole calculating. This segmentation is different from the common foreground/background segmentation problems. Our algorithm is inspired by GrabCut and consists of three main stages. First, skin area is extracted from the background scene by transforming the RGB values into the YCbCr color space. Second, a rough segmentation of normal skin and psoriasis lesion is given. This is an initial segmentation given by thresholding a single gaussian model and the thresholds are adjustable, which enables user interaction. Third, two GMMs, one for the initial normal skin and one for psoriasis lesion, are built to refine the segmentation. Experimental results demonstrate the effectiveness of the proposed algorithm.

  2. Robust Automated Amygdala Segmentation via Multi-Atlas Diffeomorphic Registration

    PubMed Central

    Hanson, Jamie L.; Suh, Jung W.; Nacewicz, Brendon M.; Sutterer, Matthew J.; Cayo, Amelia A.; Stodola, Diane E.; Burghy, Cory A.; Wang, Hongzhi; Avants, Brian B.; Yushkevich, Paul A.; Essex, Marilyn J.; Pollak, Seth D.; Davidson, Richard J.

    2012-01-01

    Here, we describe a novel method for volumetric segmentation of the amygdala from MRI images collected from 35 human subjects. This approach is adapted from open-source techniques employed previously with the hippocampus (Suh et al., 2011; Wang et al., 2011a,b). Using multi-atlas segmentation and machine learning-based correction, we were able to produce automated amygdala segments with high Dice (Mean = 0.918 for the left amygdala; 0.916 for the right amygdala) and Jaccard coefficients (Mean = 0.850 for the left; 0.846 for the right) compared to rigorously hand-traced volumes. This automated routine also produced amygdala segments with high intra-class correlations (consistency = 0.830, absolute agreement = 0.819 for the left; consistency = 0.786, absolute agreement = 0.783 for the right) and bivariate (r = 0.831 for the left; r = 0.797 for the right) compared to hand-drawn amygdala. Our results are discussed in relation to other cutting-edge segmentation techniques, as well as commonly available approaches to amygdala segmentation (e.g., Freesurfer). We believe this new technique has broad application to research with large sample sizes for which amygdala quantification might be needed. PMID:23226114

  3. Automatic MRI 2D brain segmentation using graph searching technique.

    PubMed

    Pedoia, Valentina; Binaghi, Elisabetta

    2013-09-01

    Accurate and efficient segmentation of the whole brain in magnetic resonance (MR) images is a key task in many neuroscience and medical studies either because the whole brain is the final anatomical structure of interest or because the automatic extraction facilitates further analysis. The problem of segmenting brain MRI images has been extensively addressed by many researchers. Despite the relevant achievements obtained, automated segmentation of brain MRI imagery is still a challenging problem whose solution has to cope with critical aspects such as anatomical variability and pathological deformation. In the present paper, we describe and experimentally evaluate a method for segmenting brain from MRI images basing on two-dimensional graph searching principles for border detection. The segmentation of the whole brain over the entire volume is accomplished slice by slice, automatically detecting frames including eyes. The method is fully automatic and easily reproducible by computing the internal main parameters directly from the image data. The segmentation procedure is conceived as a tool of general applicability, although design requirements are especially commensurate with the accuracy required in clinical tasks such as surgical planning and post-surgical assessment. Several experiments were performed to assess the performance of the algorithm on a varied set of MRI images obtaining good results in terms of accuracy and stability. PMID:23757180

  4. A Segmental Framework for Representing Signs Phonetically

    ERIC Educational Resources Information Center

    Johnson, Robert E.; Liddell, Scott K.

    2011-01-01

    The arguments for dividing the signing stream in signed languages into sequences of phonetic segments are compelling. The visual records of instances of actually occurring signs provide evidence of two basic types of segments: postural segments and trans-forming segments. Postural segments specify an alignment of articulatory features, both manual…

  5. Coronary atheroma composition and its association with segmental endothelial dysfunction in non-ST segment elevation myocardial infarction: novel insights with radiofrequency (iMAP) intravascular ultrasonography.

    PubMed

    Puri, Rishi; Nicholls, Stephen J; Brennan, Danielle M; Andrews, Jordan; Liew, Gary Y; Carbone, Angelo; Copus, Barbara; Nelson, Adam J; Kapadia, Samir R; Tuzcu, E Murat; Beltrame, John F; Worthley, Stephen G; Worthley, Matthew I

    2015-02-01

    Little is known of the relationship between coronary atheroma composition and corresponding endothelial dysfunction. We tested the hypothesis that segmental epicardial vasoreactivity relates to atheroma composition in patients with non-ST segment elevation myocardial infarction (NSTEMI) in vivo. In 23 NSTEMI patients referred for coronary angiography, a non-culprit vessel underwent intracoronary salbutamol (0.30 μg/min) provocation during automated IVUS pullback. A 40 MHz rotational IVUS catheter delivered radiofrequency signals at constant 67 μm intervals via a custom-built IVUS console (iMAP, iLAB, Boston Scientific). Macrovascular response [change in segmental lumen volume (SLV) at baseline and following salbutamol], percent atheroma volume (PAV) and tissue composition was evaluated in 187 contiguous non-overlapping 5 mm coronary segments. Compared with segments that dilated, constrictive segments showed similar SLV, but greater vessel volumes and PAV at baseline. The extent of necrotic and lipidic plaque was significantly greater in constrictive segments, whereas fibrotic plaque content was significantly greater in segments that dilated. Calcific plaque content did not relate to endothelium-dependent vasoreactivity. The change in SLV correlated inversely with the amount of lipidic and necrotic plaque (both r = -0.23, p = 0.002), and directly with fibrotic plaque content (r = 0.23, p = 0.002). In a multivariable model, the extent of both lipidic and necrotic plaque independently associated with segmental vasoconstriction (β = 1.2, p = 0.023; β = 0.66, p = 0.027). Following NSTEMI, both lipidic and necrotic plaque content each associate with segmental endothelial dysfunction. The link between plaque composition and vessel reactivity provides a mechanistic basis of the pathogenesis associated with vulnerable plaque in humans in vivo. PMID:25296909

  6. Semi-automatic segmentation for 3D motion analysis of the tongue with dynamic MRI.

    PubMed

    Lee, Junghoon; Woo, Jonghye; Xing, Fangxu; Murano, Emi Z; Stone, Maureen; Prince, Jerry L

    2014-12-01

    Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations. PMID:25155697

  7. Semi-automatic segmentation for 3D motion analysis of the tongue with dynamic MRI.

    PubMed

    Lee, Junghoon; Woo, Jonghye; Xing, Fangxu; Murano, Emi Z; Stone, Maureen; Prince, Jerry L

    2014-12-01

    Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations.

  8. Semi-automatic segmentation for 3D motion analysis of the tongue with dynamic MRI

    PubMed Central

    Lee, Junghoon; Woo, Jonghye; Xing, Fangxu; Murano, Emi Z.; Stone, Maureen; Prince, Jerry L.

    2014-01-01

    Dynamic MRI has been widely used to track the motion of the tongue and measure its internal deformation during speech and swallowing. Accurate segmentation of the tongue is a prerequisite step to define the target boundary and constrain the tracking to tissue points within the tongue. Segmentation of 2D slices or 3D volumes is challenging because of the large number of slices and time frames involved in the segmentation, as well as the incorporation of numerous local deformations that occur throughout the tongue during motion. In this paper, we propose a semi-automatic approach to segment 3D dynamic MRI of the tongue. The algorithm steps include seeding a few slices at one time frame, propagating seeds to the same slices at different time frames using deformable registration, and random walker segmentation based on these seed positions. This method was validated on the tongue of five normal subjects carrying out the same speech task with multi-slice 2D dynamic cine-MR images obtained at three orthogonal orientations and 26 time frames. The resulting semi-automatic segmentations of a total of 130 volumes showed an average dice similarity coefficient (DSC) score of 0.92 with less segmented volume variability between time frames than in manual segmentations. PMID:25155697

  9. A generative model for segmentation of tumor and organs-at-risk for radiation therapy planning of glioblastoma patients

    NASA Astrophysics Data System (ADS)

    Agn, Mikael; Law, Ian; Munck af Rosenschöld, Per; Van Leemput, Koen

    2016-03-01

    We present a fully automated generative method for simultaneous brain tumor and organs-at-risk segmentation in multi-modal magnetic resonance images. The method combines an existing whole-brain segmentation technique with a spatial tumor prior, which uses convolutional restricted Boltzmann machines to model tumor shape. The method is not tuned to any specific imaging protocol and can simultaneously segment the gross tumor volume, peritumoral edema and healthy tissue structures relevant for radiotherapy planning. We validate the method on a manually delineated clinical data set of glioblastoma patients by comparing segmentations of gross tumor volume, brainstem and hippocampus. The preliminary results demonstrate the feasibility of the method.

  10. Multiatlas Segmentation as Nonparametric Regression

    PubMed Central

    Awate, Suyash P.; Whitaker, Ross T.

    2015-01-01

    This paper proposes a novel theoretical framework to model and analyze the statistical characteristics of a wide range of segmentation methods that incorporate a database of label maps or atlases; such methods are termed as label fusion or multiatlas segmentation. We model these multiatlas segmentation problems as nonparametric regression problems in the high-dimensional space of image patches. We analyze the nonparametric estimator’s convergence behavior that characterizes expected segmentation error as a function of the size of the multiatlas database. We show that this error has an analytic form involving several parameters that are fundamental to the specific segmentation problem (determined by the chosen anatomical structure, imaging modality, registration algorithm, and label-fusion algorithm). We describe how to estimate these parameters and show that several human anatomical structures exhibit the trends modeled analytically. We use these parameter estimates to optimize the regression estimator. We show that the expected error for large database sizes is well predicted by models learned on small databases. Thus, a few expert segmentations can help predict the database sizes required to keep the expected error below a specified tolerance level. Such cost-benefit analysis is crucial for deploying clinical multiatlas segmentation systems. PMID:24802528

  11. Intraparenchymal hemorrhage segmentation from clinical head CT of patients with traumatic brain injury

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; Wilkes, Sean; Diaz-Arrastia, Ramon; Butman, John A.; Pham, Dzung L.

    2015-03-01

    Quantification of hemorrhages in head computed tomography (CT) images from patients with traumatic brain injury (TBI) has potential applications in monitoring disease progression and better understanding of the patho-physiology of TBI. Although manual segmentations can provide accurate measures of hemorrhages, the processing time and inter-rater variability make it infeasible for large studies. In this paper, we propose a fully automatic novel pipeline for segmenting intraparenchymal hemorrhages (IPH) from clinical head CT images. Unlike previous methods of model based segmentation or active contour techniques, we rely on relevant and matching examples from already segmented images by trained raters. The CT images are first skull-stripped. Then example patches from an "atlas" CT and its manual segmentation are used to learn a two-class sparse dictionary for hemorrhage and normal tissue. Next, for a given "subject" CT, a subject patch is modeled as a sparse convex combination of a few atlas patches from the dictionary. The same convex combination is applied to the atlas segmentation patches to generate a membership for the hemorrhages at each voxel. Hemorrhages are segmented from 25 subjects with various degrees of TBI. Results are compared with segmentations obtained from an expert rater. A median Dice coefficient of 0.85 between automated and manual segmentations is achieved. A linear fit between automated and manual volumes show a slope of 1.0047, indicating a negligible bias in volume estimation.

  12. Isomap transform for segmenting human body shapes.

    PubMed

    Cerveri, P; Sarro, K J; Marchente, M; Barros, R M L

    2011-09-01

    Segmentation of the 3D human body is a very challenging problem in applications exploiting volume capture data. Direct clustering in the Euclidean space is usually complex or even unsolvable. This paper presents an original method based on the Isomap (isometric feature mapping) transform of the volume data-set. The 3D articulated posture is mapped by Isomap in the pose of Da Vinci's Vitruvian man. The limbs are unrolled from each other and separated from the trunk and pelvis, and the topology of the human body shape is recovered. In such a configuration, Hoshen-Kopelman clustering applied to concentric spherical shells is used to automatically group points into the labelled principal curves. Shepard interpolation is utilised to back-map points of the principal curves into the original volume space. The experimental results performed on many different postures have proved the validity of the proposed method. Reliability of less than 2 cm and 3° in the location of the joint centres and direction axes of rotations has been obtained, respectively, which qualifies this procedure as a potential tool for markerless motion analysis.

  13. Asymmetric bias in user guided segmentations of brain structures.

    PubMed

    Maltbie, Eric; Bhatt, Kshamta; Paniagua, Beatriz; Smith, Rachel G; Graves, Michael M; Mosconi, Matthew W; Peterson, Sarah; White, Scott; Blocher, Joseph; El-Sayed, Mohammed; Hazlett, Heather C; Styner, Martin A

    2012-01-16

    Brain morphometric studies often incorporate comparative hemispheric asymmetry analyses of segmented brain structures. In this work, we present evidence that common user guided structural segmentation techniques exhibit strong left-right asymmetric biases and thus fundamentally influence any left-right asymmetry analyses. In this study, MRI scans from ten pediatric subjects were employed for studying segmentations of amygdala, globus pallidus, putamen, caudate, and lateral ventricle. Additionally, two pediatric and three adult scans were used for studying hippocampus segmentation. Segmentations of the sub-cortical structures were performed by skilled raters using standard manual and semi-automated methods. The left-right mirrored versions of each image were included in the data and segmented in a random order to assess potential left-right asymmetric bias. Using shape analysis we further assessed whether the asymmetric bias is consistent across subjects and raters with the focus on the hippocampus. The user guided segmentation techniques on the sub-cortical structures exhibited left-right asymmetric volume bias with the hippocampus displaying the most significant asymmetry values (p<0.01). The hippocampal shape analysis revealed the bias to be strongest on the lateral side of the body and medial side of the head and tail. The origin of this asymmetric bias is considered to be based in laterality of visual perception; therefore segmentations with any degree of user interaction contain an asymmetric bias. The aim of our study is to raise awareness in the neuroimaging community regarding the presence of the asymmetric bias and its influence on any left-right hemispheric analyses. We also recommend reexamining previous research results in the light of this new finding. PMID:21889995

  14. Automatic segmentation of anterior segment optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Williams, Dominic; Zheng, Yalin; Bao, Fangjun; Elsheikh, Ahmed

    2013-05-01

    Optical coherence tomography (OCT) images can provide quantitative measurements of the eye's entire anterior segment. A new technique founded on a newly proposed level set-based shape prior segmentation model has been developed for automatic segmentation of the cornea's anterior and posterior boundaries. This technique comprises three major steps: removal of regions containing irrelevant structures and artifacts, estimation of the cornea's location using a thresholding technique, and application of the new level set-based shape prior segmentation model to improve segmentation. The performance of our technique is compared to previously developed methods for analysis of the cornea in 33 OCT images of normal eyes, whereby manual annotations are used as a reference standard. The new technique achieves much improved concordance than previous methods, with a mean Dice's similarity coefficient of >0.92. This demonstrates the technique's potential to provide accurate and reliable measurements of the anterior segment geometry, which is important for many applications, including the construction of representative numerical simulations of the eye's mechanical behavior.

  15. Automatic segmentation of anterior segment optical coherence tomography images.

    PubMed

    Williams, Dominic; Zheng, Yalin; Bao, Fangjun; Elsheikh, Ahmed

    2013-05-01

    Optical coherence tomography (OCT) images can provide quantitative measurements of the eye's entire anterior segment. A new technique founded on a newly proposed level set-based shape prior segmentation model has been developed for automatic segmentation of the cornea's anterior and posterior boundaries. This technique comprises three major steps: removal of regions containing irrelevant structures and artifacts, estimation of the cornea's location using a thresholding technique, and application of the new level set-based shape prior segmentation model to improve segmentation. The performance of our technique is compared to previously developed methods for analysis of the cornea in 33 OCT images of normal eyes, whereby manual annotations are used as a reference standard. The new technique achieves much improved concordance than previous methods, with a mean Dice's similarity coefficient of > 0.92. This demonstrates the technique's potential to provide accurate and reliable measurements of the anterior segment geometry, which is important for many applications, including the construction of representative numerical simulations of the eye's mechanical behavior. PMID:23640074

  16. Extracting and summarizing white matter hyperintensities using supervised segmentation methods in Alzheimer’s disease risk and aging studies

    PubMed Central

    Ithapu, Vamsi; Singh, Vikas; Lindner, Christopher; Austin, Benjamin P.; Hinrichs, Chris; Carlsson, Cynthia M.; Bendlin, Barbara B.; Johnson, Sterling C.

    2014-01-01

    Precise detection and quantification of white matter hyperintensities (WMH) observed in T2–weighted Fluid Attenuated Inversion Recovery (FLAIR) Magnetic Resonance Images (MRI) is of substantial interest in aging, and age related neurological disorders such as Alzheimer’s disease (AD). This is mainly because WMH may reflect comorbid neural injury or cerebral vascular disease burden. WMH in the older population may be small, diffuse and irregular in shape, and sufficiently heterogeneous within and across subjects. Here, we pose hyperintensity detection as a supervised inference problem and adapt two learning models, specifically, Support Vector Machines and Random Forests, for this task. Using texture features engineered by texton filter banks, we provide a suite of effective segmentation methods for this problem. Through extensive evaluations on healthy middle–aged and older adults who vary in AD risk, we show that our methods are reliable and robust in segmenting hyperintense regions. A measure of hyperintensity accumulation, referred to as normalized Effective WMH Volume, is shown to be associated with dementia in older adults and parental family history in cognitively normal subjects. We provide an open source library for hyperintensity detection and accumulation (interfaced with existing neuroimaging tools), that can be adapted for segmentation problems in other neuroimaging studies. PMID:24510744

  17. In vivo pediatric shoulder muscle volumes and their relationship to 3D strength.

    PubMed

    Im, Hyun Soo; Alter, Katharine E; Brochard, Sylvain; Pons, Christelle; Sheehan, Frances T

    2014-08-22

    In the pediatric shoulder, injury and pathology can disrupt the muscle force balance, resulting in severe functional losses. As little data exists pertaining to in vivo pediatric shoulder muscle function, musculoskeletal data are crucially needed to advance the treatment of pediatric shoulder pathology/injury. Therefore, the purpose of this study was to develop a pediatric database of in vivo volumes for the major shoulder muscles and correlate these volumes with maximum isometric flexion/extension, internal/external rotation, and abduction/adduction joint moments. A methodology was developed to derive 3D shoulder muscle volumes and to divide the deltoid into sub-units with unique torque producing capabilities, based on segmentation of three-dimensional magnetic resonance images. Eleven typically developing children/adolescents (4F/7M, 12.0 ± 3.2 years, 150.8 ± 16.7 cm, 49.2 ± 16.4 kg) participated. Correlation and regression analyses were used to evaluate the relationship between volume and maximum, voluntary, isometric joint torques. The deltoid demonstrated the largest (30.4 ± 1.2%) and the supraspinatus the smallest (4.8 ± 0.5%) percent of the total summed volume of all six muscles evaluated. The anterior and posterior deltoid sections were 43.4 ± 3.9% and 56.6 ± 3.9% of the total deltoid volume. The percent volumes were highly consistent across subjects. Individual muscle volumes demonstrated moderate-high correlations with torque values (0.70-0.94, p<0.001). This study presents a comprehensive database documenting normative pediatric shoulder muscle volume. Using these data a clear relationship between shoulder volume and the torques they produce was established in all three rotational degrees-of-freedom. This study furthers the understanding of shoulder muscle function and serves as a foundation for evaluating shoulder injury/pathology in the pediatric/adolescent population. PMID:24925254

  18. Image segmentation using an improved differential algorithm

    NASA Astrophysics Data System (ADS)

    Gao, Hao; Shi, Yujiao; Wu, Dongmei

    2014-10-01

    Among all the existing segmentation techniques, the thresholding technique is one of the most popular due to its simplicity, robustness, and accuracy (e.g. the maximum entropy method, Otsu's method, and K-means clustering). However, the computation time of these algorithms grows exponentially with the number of thresholds due to their exhaustive searching strategy. As a population-based optimization algorithm, differential algorithm (DE) uses a population of potential solutions and decision-making processes. It has shown considerable success in solving complex optimization problems within a reasonable time limit. Thus, applying this method into segmentation algorithm should be a good choice during to its fast computational ability. In this paper, we first propose a new differential algorithm with a balance strategy, which seeks a balance between the exploration of new regions and the exploitation of the already sampled regions. Then, we apply the new DE into the traditional Otsu's method to shorten the computation time. Experimental results of the new algorithm on a variety of images show that, compared with the EA-based thresholding methods, the proposed DE algorithm gets more effective and efficient results. It also shortens the computation time of the traditional Otsu method.

  19. Health Lifestyles: Audience Segmentation Analysis for Public Health Interventions.

    ERIC Educational Resources Information Center

    Slater, Michael D.; Flora, June A.

    This paper is concerned with the application of market research techniques to segment large populations into homogeneous units in order to improve the reach, utilization, and effectiveness of health programs. The paper identifies seven distinctive patterns of health attitudes, social influences, and behaviors using cluster analytic techniques in a…

  20. Pattern of care and effectiveness of treatment for glioblastoma patients in the real world: Results from a prospective population-based registry. Could survival differ in a high-volume center?

    PubMed Central

    Brandes, Alba A.; Franceschi, Enrico; Ermani, Mario; Tosoni, Alicia; Albani, Fiorenzo; Depenni, Roberta; Faedi, Marina; Pisanello, Anna; Crisi, Girolamo; Urbini, Benedetta; Dazzi, Claudio; Cavanna, Luigi; Mucciarini, Claudia; Pasini, Giuseppe; Bartolini, Stefania; Marucci, Gianluca; Morandi, Luca; Zunarelli, Elena; Cerasoli, Serenella; Gardini, Giorgio; Lanza, Giovanni; Silini, Enrico Maria; Cavuto, Silvio; Baruzzi, Agostino

    2014-01-01

    Background As yet, no population-based prospective studies have been conducted to investigate the incidence and clinical outcome of glioblastoma (GBM) or the diffusion and impact of the current standard therapeutic approach in newly diagnosed patients younger than aged 70 years. Methods Data on all new cases of primary brain tumors observed from January 1, 2009, to December 31, 2010, in adults residing within the Emilia-Romagna region were recorded in a prospective registry in the Project of Emilia Romagna on Neuro-Oncology (PERNO). Based on the data from this registry, a prospective evaluation was made of the treatment efficacy and outcome in GBM patients. Results Two hundred sixty-seven GBM patients (median age, 64 y; range, 29–84 y) were enrolled. The median overall survival (OS) was 10.7 months (95% CI, 9.2–12.4). The 139 patients ≤aged 70 years who were given standard temozolomide treatment concomitant with and adjuvant to radiotherapy had a median OS of 16.4 months (95% CI, 14.0–18.5). With multivariate analysis, OS correlated significantly with KPS (HR = 0.458; 95% CI, 0.248–0.847; P = .0127), MGMT methylation status (HR = 0.612; 95% CI, 0.388–0.966; P = .0350), and treatment received in a high versus low-volume center (HR = 0.56; 95% CI, 0.328–0.986; P = .0446). Conclusions The median OS following standard temozolomide treatment concurrent with and adjuvant to radiotherapy given to (72.8% of) patients aged ≤70 years is consistent with findings reported from randomized phase III trials. The volume and expertise of the treatment center should be further investigated as a prognostic factor. PMID:26034628

  1. Metrology of IXO Mirror Segments

    NASA Technical Reports Server (NTRS)

    Chan, Kai-Wing

    2011-01-01

    For future x-ray astrophysics mission that demands optics with large throughput and excellent angular resolution, many telescope concepts build around assembling thin mirror segments in a Wolter I geometry, such as that originally proposed for the International X-ray Observatory. The arc-second resolution requirement posts unique challenges not just for fabrication, mounting but also for metrology of these mirror segments. In this paper, we shall discuss the metrology of these segments using normal incidence metrological method with interferometers and null lenses. We present results of the calibration of the metrology systems we are currently using, discuss their accuracy and address the precision in measuring near-cylindrical mirror segments and the stability of the measurements.

  2. Texture segmentation by genetic programming.

    PubMed

    Song, Andy; Ciesielski, Vic

    2008-01-01

    This paper describes a texture segmentation method using genetic programming (GP), which is one of the most powerful evolutionary computation algorithms. By choosing an appropriate representation texture, classifiers can be evolved without computing texture features. Due to the absence of time-consuming feature extraction, the evolved classifiers enable the development of the proposed texture segmentation algorithm. This GP based method can achieve a segmentation speed that is significantly higher than that of conventional methods. This method does not require a human expert to manually construct models for texture feature extraction. In an analysis of the evolved classifiers, it can be seen that these GP classifiers are not arbitrary. Certain textural regularities are captured by these classifiers to discriminate different textures. GP has been shown in this study as a feasible and a powerful approach for texture classification and segmentation, which are generally considered as complex vision tasks.

  3. Bayesian segmentation of hyperspectral images

    NASA Astrophysics Data System (ADS)

    Mohammadpour, Adel; Féron, Olivier; Mohammad-Djafari, Ali

    2004-11-01

    In this paper we consider the problem of joint segmentation of hyperspectral images in the Bayesian framework. The proposed approach is based on a Hidden Markov Modeling (HMM) of the images with common segmentation, or equivalently with common hidden classification label variables which is modeled by a Potts Markov Random Field. We introduce an appropriate Markov Chain Monte Carlo (MCMC) algorithm to implement the method and show some simulation results.

  4. Video segmentation techniques for news

    NASA Astrophysics Data System (ADS)

    Phillips, Michael; Wolf, Wayne H.

    1996-11-01

    This paper describes our experiences in video analysis for a video library on the World Wide Web. News and documentary programs, though seemingly simple, have some characteristics which can cause problems in simple shot segmentation algorithms. We have developed a methodology, based on our experience with the analysis of several hours of news/documentary footage, which improve the results of shot segmentation on this type of material and which in turn allows for higher-quality storyboards for our video library.

  5. A framework for probabilistic atlas-based organ segmentation

    NASA Astrophysics Data System (ADS)

    Dong, Chunhua; Chen, Yen-Wei; Foruzan, Amir Hossein; Han, Xian-Hua; Tateyama, Tomoko; Wu, Xing

    2016-03-01

    Probabilistic atlas based on human anatomical structure has been widely used for organ segmentation. The challenge is how to register the probabilistic atlas to the patient volume. Additionally, there is the disadvantage that the conventional probabilistic atlas may cause a bias toward the specific patient study due to a single reference. Hence, we propose a template matching framework based on an iterative probabilistic atlas for organ segmentation. Firstly, we find a bounding box for the organ based on human anatomical localization. Then, the probabilistic atlas is used as a template to find the organ in this bounding box by using template matching technology. Comparing our method with conventional and recently developed atlas-based methods, our results show an improvement in the segmentation accuracy for multiple organs (p < 0:00001).

  6. Radio frequency ablation registration, segmentation, and fusion tool.

    PubMed

    McCreedy, Evan S; Cheng, Ruida; Hemler, Paul F; Viswanathan, Anand; Wood, Bradford J; McAuliffe, Matthew J

    2006-07-01

    The radio frequency ablation segmentation tool (RFAST) is a software application developed using the National Institutes of Health's medical image processing analysis and visualization (MIPAV) API for the specific purpose of assisting physicians in the planning of radio frequency ablation (RFA) procedures. The RFAST application sequentially leads the physician through the steps necessary to register, fuse, segment, visualize, and plan the RFA treatment. Three-dimensional volume visualization of the CT dataset with segmented three dimensional (3-D) surface models enables the physician to interactively position the ablation probe to simulate burns and to semimanually simulate sphere packing in an attempt to optimize probe placement. This paper describes software systems contained in RFAST to address the needs of clinicians in planning, evaluating, and simulating RFA treatments of malignant hepatic tissue. PMID:16871716

  7. Automated Segmentation and Shape Characterization of Volumetric Data

    PubMed Central

    Galinsky, Vitaly L.; Frank, Lawrence R.

    2015-01-01

    Characterization of complex shapes embedded within volumetric data is an important step in a wide range of applications. Standard approaches to this problem employ surface based methods that require inefficient, time consuming, and error prone steps of surface segmentation and inflation to satisfy the uniqueness or stability of subsequent surface fitting algorithms. Here we present a novel method based on a spherical wave decomposition (SWD) of the data that overcomes several of these limitations by directly analyzing the entire data volume, obviating the segmentation, inflation, and surface fitting steps, significantly reducing the computational time and eliminating topological errors while providing a more detailed quantitative description based upon a more complete theoretical framework of volumetric data. The method is demonstrated and compared to the current state-of-the-art neuroimaging methods for segmentation and characterization of volumetric magnetic resonance imaging data of the human brain. PMID:24521852

  8. Data Mining for Customer Segmentation in Personal Financial Market

    NASA Astrophysics Data System (ADS)

    Wang, Guoxun; Li, Fang; Zhang, Peng; Tian, Yingjie; Shi, Yong

    The personal financial market segmentation plays an important role in retail banking. It is widely admitted that there are a lot of limitations of conventional ways in customer segmentation, which are knowledge based and often get bias results. In contrast, data mining can deal with mass of data and never miss any useful knowledge. Due to the mass storage volume of unlabeled transaction data, in this paper, we propose a clustering ensemble method based on majority voting mechanism and two alternative manners to further enhance the performance of customer segmentation in real banking business. Through the experiments and examinations in real business environment, we can come to a conclusion that our model reflect the true characteristics of various types of customers and can be used to find the investment preferences of customers.

  9. The Envisat-1 ground segment

    NASA Astrophysics Data System (ADS)

    Harris, Ray; Ashton, Martin

    1995-03-01

    The European Space Agency (ESA) Earth Remote Sensing Satellite (ERS-1 and ERS-2) missions will be followed by the Polar Orbit Earth Mission (POEM) program. The first of the POEM missions will be Envisat-1. ESA has completed the design phase of the ground segment. This paper presents the main elements of that design. The main part of this paper is an overview of the Payload Data Segment (PDS) which is the core of the Envisat-1 ground segment, followed by two further sections which describe in more detail the facilities to be offered by the PDS for archiving and for user servcies. A further section describes some future issues for ground segment development. Logica was the prime contractor of a team of 18 companies which undertook the ESA financed architectural design study of the Envisat-1 ground segment. The outputs of the study included detailed specifications of the components that will acquire, process, archive and disseminate the payload data, together with the functional designs of the flight operations and user data segments.

  10. Efficient threshold for volumetric segmentation

    NASA Astrophysics Data System (ADS)

    Burdescu, Dumitru D.; Brezovan, Marius; Stanescu, Liana; Stoica Spahiu, Cosmin; Ebanca, Daniel

    2015-07-01

    Image segmentation plays a crucial role in effective understanding of digital images. However, the research on the existence of general purpose segmentation algorithm that suits for variety of applications is still very much active. Among the many approaches in performing image segmentation, graph based approach is gaining popularity primarily due to its ability in reflecting global image properties. Volumetric image segmentation can simply result an image partition composed by relevant regions, but the most fundamental challenge in segmentation algorithm is to precisely define the volumetric extent of some object, which may be represented by the union of multiple regions. The aim in this paper is to present a new method to detect visual objects from color volumetric images and efficient threshold. We present a unified framework for volumetric image segmentation and contour extraction that uses a virtual tree-hexagonal structure defined on the set of the image voxels. The advantage of using a virtual tree-hexagonal network superposed over the initial image voxels is that it reduces the execution time and the memory space used, without losing the initial resolution of the image.

  11. [Automatic segmentation and annotation in radiology].

    PubMed

    Dankerl, P; Cavallaro, A; Uder, M; Hammon, M

    2014-03-01

    The technical progress and broader indications for cross-sectional imaging continuously increase the number of radiological images to be assessed. However, as the amount of image information and available resources (radiologists) do not increase at the same pace and the standards of radiological interpretation and reporting remain consistently high, radiologists have to rely on computer-based support systems. Novel semantic technologies and software relying on structured ontological knowledge are able to "understand" text and image information and interconnect both. This allows complex database queries with both the input of text and image information to be accomplished. Furthermore, semantic software in combination with automatic detection and segmentation of organs and body regions facilitates personalized supportive information in topographical accordance and generates additional information, such as organ volumes. These technologies promise improvements in workflow; however, great efforts and close cooperation between developers and users still lie ahead. PMID:24522625

  12. Automatic scale selection for medical image segmentation

    NASA Astrophysics Data System (ADS)

    Bayram, Ersin; Wyatt, Christopher L.; Ge, Yaorong

    2001-07-01

    The scale of interesting structures in medical images is space variant because of partial volume effects, spatial dependence of resolution in many imaging modalities, and differences in tissue properties. Existing segmentation methods either apply a single scale to the entire image or try fine-to-coarse/coarse-to-fine tracking of structures over multiple scales. While single scale approaches fail to fully recover the perceptually important structures, multi-scale methods have problems in providing reliable means to select proper scales and integrating information over multiple scales. A recent approach proposed by Elder and Zucker addresses the scale selection problem by computing a minimal reliable scale for each image pixel. The basic premise of this approach is that, while the scale of structures within an image vary spatially, the imaging system is fixed. Hence, sensor noise statistics can be calculated. Based on a model of edges to be detected, and operators to be used for detection, one can locally compute a unique minimal reliable scale at which the likelihood of error due to sensor noise is less than or equal to a predetermined threshold. In this paper, we improve the segmentation method based on the minimal reliable scale selection and evaluate its effectiveness with both simulated and actual medical data.

  13. Automatic segmentation and reconstruction of the cortex from neonatal MRI.

    PubMed

    Xue, Hui; Srinivasan, Latha; Jiang, Shuzhou; Rutherford, Mary; Edwards, A David; Rueckert, Daniel; Hajnal, Joseph V

    2007-11-15

    Segmentation and reconstruction of cortical surfaces from magnetic resonance (MR) images are more challenging for developing neonates than adults. This is mainly due to the dynamic changes in the contrast between gray matter (GM) and white matter (WM) in both T1- and T2-weighted images (T1w and T2w) during brain maturation. In particular in neonatal T2w images WM typically has higher signal intensity than GM. This causes mislabeled voxels during cortical segmentation, especially in the cortical regions of the brain and in particular at the interface between GM and cerebrospinal fluid (CSF). We propose an automatic segmentation algorithm detecting these mislabeled voxels and correcting errors caused by partial volume effects. Our results show that the proposed algorithm corrects errors in the segmentation of both GM and WM compared to the classic expectation maximization (EM) scheme. Quantitative validation against manual segmentation demonstrates good performance (the mean Dice value: 0.758+/-0.037 for GM and 0.794+/-0.078 for WM). The inner, central and outer cortical surfaces are then reconstructed using implicit surface evolution. A landmark study is performed to verify the accuracy of the reconstructed cortex (the mean surface reconstruction error: 0.73 mm for inner surface and 0.63 mm for the outer). Both segmentation and reconstruction have been tested on 25 neonates with the gestational ages ranging from approximately 27 to 45 weeks. This preliminary analysis confirms previous findings that cortical surface area and curvature increase with age, and that surface area scales to cerebral volume according to a power law, while cortical thickness is not related to age or brain growth. PMID:17888685

  14. Knowledge-based 3D segmentation of the brain in MR images for quantitative multiple sclerosis lesion tracking

    NASA Astrophysics Data System (ADS)

    Fisher, Elizabeth; Cothren, Robert M., Jr.; Tkach, Jean A.; Masaryk, Thomas J.; Cornhill, J. Fredrick

    1997-04-01

    Brain segmentation in magnetic resonance (MR) images is an important step in quantitative analysis applications, including the characterization of multiple sclerosis (MS) lesions over time. Our approach is based on a priori knowledge of the intensity and three-dimensional (3D) spatial relationships of structures in MR images of the head. Optimal thresholding and connected-components analysis are used to generate a starting point for segmentation. A 3D radial search is then performed to locate probable locations of the intra-cranial cavity (ICC). Missing portions of the ICC surface are interpolated in order to exclude connected structures. Partial volume effects and inter-slice intensity variations in the image are accounted for automatically. Several studies were conducted to validate the segmentation. Accuracy was tested by calculating the segmented volume and comparing to known volumes of a standard MR phantom. Reliability was tested by comparing calculated volumes of individual segmentation results from multiple images of the same subject. The segmentation results were also compared to manual tracings. The average error in volume measurements for the phantom was 1.5% and the average coefficient of variation of brain volume measurements of the same subject was 1.2%. Since the new algorithm requires minimal user interaction, variability introduced by manual tracing and interactive threshold or region selection was eliminated. Overall, the new algorithm was shown to produce a more accurate and reliable brain segmentation than existing manual and semi-automated techniques.

  15. A method for the evaluation of thousands of automated 3D stem cell segmentations.

    PubMed

    Bajcsy, P; Simon, M; Florczyk, S J; Simon, C G; Juba, D; Brady, M C

    2015-12-01

    There is no segmentation method that performs perfectly with any dataset in comparison to human segmentation. Evaluation procedures for segmentation algorithms become critical for their selection. The problems associated with segmentation performance evaluations and visual verification of segmentation results are exaggerated when dealing with thousands of three-dimensional (3D) image volumes because of the amount of computation and manual inputs needed. We address the problem of evaluating 3D segmentation performance when segmentation is applied to thousands of confocal microscopy images (z-stacks). Our approach is to incorporate experimental imaging and geometrical criteria, and map them into computationally efficient segmentation algorithms that can be applied to a very large number of z-stacks. This is an alternative approach to considering existing segmentation methods and evaluating most state-of-the-art algorithms. We designed a methodology for 3D segmentation performance characterization that consists of design, evaluation and verification steps. The characterization integrates manual inputs from projected surrogate 'ground truth' of statistically representative samples and from visual inspection into the evaluation. The novelty of the methodology lies in (1) designing candidate segmentation algorithms by mapping imaging and geometrical criteria into algorithmic steps, and constructing plausible segmentation algorithms with respect to the order of algorithmic steps and their parameters, (2) evaluating segmentation accuracy using samples drawn from probability distribution estimates of candidate segmentations and (3) minimizing human labour needed to create surrogate 'truth' by approximating z-stack segmentations with 2D contours from three orthogonal z-stack projections and by developing visual verification tools. We demonstrate the methodology by applying it to a dataset of 1253 mesenchymal stem cells. The cells reside on 10 different types of biomaterial

  16. Liver segmentation for CT images using GVF snake

    SciTech Connect

    Liu Fan; Zhao Binsheng; Kijewski, Peter K.; Wang Liang; Schwartz, Lawrence H.

    2005-12-15

    Accurate liver segmentation on computed tomography (CT) images is a challenging task especially at sites where surrounding tissues (e.g., stomach, kidney) have densities similar to that of the liver and lesions reside at the liver edges. We have developed a method for semiautomatic delineation of the liver contours on contrast-enhanced CT images. The method utilizes a snake algorithm with a gradient vector flow (GVF) field as its external force. To improve the performance of the GVF snake in the segmentation of the liver contour, an edge map was obtained with a Canny edge detector, followed by modifications using a liver template and a concavity removal algorithm. With the modified edge map, for which unwanted edges inside the liver were eliminated, the GVF field was computed and an initial liver contour was formed. The snake algorithm was then applied to obtain the actual liver contour. This algorithm was extended to segment the liver volume in a slice-by-slice fashion, where the result of the preceding slice constrained the segmentation of the adjacent slice. 551 two-dimensional liver images from 20 volumetric images with colorectal metastases spreading throughout the livers were delineated using this method, and also manually by a radiologist for evaluation. The difference ratio, which is defined as the percentage ratio of mismatching volume between the computer and the radiologist's results, ranged from 2.9% to 7.6% with a median value of 5.3%.

  17. Fuzzy object models for newborn brain MR image segmentation

    NASA Astrophysics Data System (ADS)

    Kobashi, Syoji; Udupa, Jayaram K.

    2013-03-01

    Newborn brain MR image segmentation is a challenging problem because of variety of size, shape and MR signal although it is the fundamental study for quantitative radiology in brain MR images. Because of the large difference between the adult brain and the newborn brain, it is difficult to directly apply the conventional methods for the newborn brain. Inspired by the original fuzzy object model introduced by Udupa et al. at SPIE Medical Imaging 2011, called fuzzy shape object model (FSOM) here, this paper introduces fuzzy intensity object model (FIOM), and proposes a new image segmentation method which combines the FSOM and FIOM into fuzzy connected (FC) image segmentation. The fuzzy object models are built from training datasets in which the cerebral parenchyma is delineated by experts. After registering FSOM with the evaluating image, the proposed method roughly recognizes the cerebral parenchyma region based on a prior knowledge of location, shape, and the MR signal given by the registered FSOM and FIOM. Then, FC image segmentation delineates the cerebral parenchyma using the fuzzy object models. The proposed method has been evaluated using 9 newborn brain MR images using the leave-one-out strategy. The revised age was between -1 and 2 months. Quantitative evaluation using false positive volume fraction (FPVF) and false negative volume fraction (FNVF) has been conducted. Using the evaluation data, a FPVF of 0.75% and FNVF of 3.75% were achieved. More data collection and testing are underway.

  18. Brain segmentation and the generation of cortical surfaces

    NASA Technical Reports Server (NTRS)

    Joshi, M.; Cui, J.; Doolittle, K.; Joshi, S.; Van Essen, D.; Wang, L.; Miller, M. I.

    1999-01-01

    This paper describes methods for white matter segmentation in brain images and the generation of cortical surfaces from the segmentations. We have developed a system that allows a user to start with a brain volume, obtained by modalities such as MRI or cryosection, and constructs a complete digital representation of the cortical surface. The methodology consists of three basic components: local parametric modeling and Bayesian segmentation; surface generation and local quadratic coordinate fitting; and surface editing. Segmentations are computed by parametrically fitting known density functions to the histogram of the image using the expectation maximization algorithm [DLR77]. The parametric fits are obtained locally rather than globally over the whole volume to overcome local variations in gray levels. To represent the boundary of the gray and white matter we use triangulated meshes generated using isosurface generation algorithms [GH95]. A complete system of local parametric quadratic charts [JWM+95] is superimposed on the triangulated graph to facilitate smoothing and geodesic curve tracking. Algorithms for surface editing include extraction of the largest closed surface. Results for several macaque brains are presented comparing automated and hand surface generation. Copyright 1999 Academic Press.

  19. Communicative functions integrate segments in prosodies and prosodies in segments.

    PubMed

    Kohler, Klaus J

    2011-01-01

    This paper takes a new look at the traditionally established divide between sounds and prosodies, viewing it as a useful heuristics in language descriptions that focus on the segmental make- up of words. It pleads for a new approach that bridges this reified compartmentalization of speech in a more global communicative perspective. Data are presented from a German perception experiment in the framework of the Semantic Differential that shows interdependence of f0 contours and the spectral characteristics of a following fricative segment, for the expression of semantic functions along the scales questioning - asserting, excited - calm, forceful - not forceful, contrary - agreeable. The results lead to the conclusion that segments shape prosodies and are shaped by them in varying ways in the coding of semantic functions. This implies that the analysis of sentence prosodies needs to integrate the manifestation of segments, just as the analysis of segments needs to consider their prosodic embedding. In communicative interaction, speakers set broad prosodic time windows of varying sizes, and listeners respond to them. So, future phonetic research needs to concentrate on speech analysis in such windows.

  20. Automated segmentation of in vivo and ex vivo mouse brain magnetic resonance images.

    PubMed

    Scheenstra, Alize E H; van de Ven, Rob C G; van der Weerd, Louise; van den Maagdenberg, Arn M J M; Dijkstra, Jouke; Reiber, Johan H C

    2009-01-01

    Segmentation of magnetic resonance imaging (MRI) data is required for many applications, such as the comparison of different structures or time points, and for annotation purposes. Currently, the gold standard for automated image segmentation is nonlinear atlas-based segmentation. However, these methods are either not sufficient or highly time consuming for mouse brains, owing to the low signal to noise ratio and low contrast between structures compared with other applications. We present a novel generic approach to reduce processing time for segmentation of various structures of mouse brains, in vivo and ex vivo. The segmentation consists of a rough affine registration to a template followed by a clustering approach to refine the rough segmentation near the edges. Compared with manual segmentations, the presented segmentation method has an average kappa index of 0.7 for 7 of 12 structures in in vivo MRI and 11 of 12 structures in ex vivo MRI. Furthermore, we found that these results were equal to the performance of a nonlinear segmentation method, but with the advantage of being 8 times faster. The presented automatic segmentation method is quick and intuitive and can be used for image registration, volume quantification of structures, and annotation. PMID:19344574

  1. Atlas Based Segmentation and Mapping of Organs at Risk from Planning CT for the Development of Voxel-Wise Predictive Models of Toxicity in Prostate Radiotherapy

    NASA Astrophysics Data System (ADS)

    Acosta, Oscar; Dowling, Jason; Cazoulat, Guillaume; Simon, Antoine; Salvado, Olivier; de Crevoisier, Renaud; Haigron, Pascal

    The prediction of toxicity is crucial to managing prostate cancer radiotherapy (RT). This prediction is classically organ wise and based on the dose volume histograms (DVH) computed during the planning step, and using for example the mathematical Lyman Normal Tissue Complication Probability (NTCP) model. However, these models lack spatial accuracy, do not take into account deformations and may be inappropiate to explain toxicity events related with the distribution of the delivered dose. Producing voxel wise statistical models of toxicity might help to explain the risks linked to the dose spatial distribution but is challenging due to the difficulties lying on the mapping of organs and dose in a common template. In this paper we investigate the use of atlas based methods to perform the non-rigid mapping and segmentation of the individuals' organs at risk (OAR) from CT scans. To build a labeled atlas, 19 CT scans were selected from a population of patients treated for prostate cancer by radiotherapy. The prostate and the OAR (Rectum, Bladder, Bones) were then manually delineated by an expert and constituted the training data. After a number of affine and non rigid registration iterations, an average image (template) representing the whole population was obtained. The amount of consensus between labels was used to generate probabilistic maps for each organ. We validated the accuracy of the approach by segmenting the organs using the training data in a leave one out scheme. The agreement between the volumes after deformable registration and the manually segmented organs was on average above 60% for the organs at risk. The proposed methodology provides a way to map the organs from a whole population on a single template and sets the stage to perform further voxel wise analysis. With this method new and accurate predictive models of toxicity will be built.

  2. Quantum volume

    NASA Astrophysics Data System (ADS)

    Ryabov, V. A.

    2015-08-01

    Quantum systems in a mechanical embedding, the breathing mode of a small particles, optomechanical system, etc. are far not the full list of examples in which the volume exhibits quantum behavior. Traditional consideration suggests strain in small systems as a result of a collective movement of particles, rather than the dynamics of the volume as an independent variable. The aim of this work is to show that some problem here might be essentially simplified by introducing periodic boundary conditions. At this case, the volume is considered as the independent dynamical variable driven by the internal pressure. For this purpose, the concept of quantum volume based on Schrödinger’s equation in 𝕋3 manifold is proposed. It is used to explore several 1D model systems: An ensemble of free particles under external pressure, quantum manometer and a quantum breathing mode. In particular, the influence of the pressure of free particle on quantum oscillator is determined. It is shown also that correction to the spectrum of the breathing mode due to internal degrees of freedom is determined by the off-diagonal matrix elements of the quantum stress. The new treatment not using the “force” theorem is proposed for the quantum stress tensor. In the general case of flexible quantum 3D dynamics, quantum deformations of different type might be introduced similarly to monopole mode.

  3. Association of Habitual Patterns and Types of Physical Activity and Inactivity with MRI-Determined Total Volumes of Visceral and Subcutaneous Abdominal Adipose Tissue in a General White Population.

    PubMed

    Fischer, Karina; Rüttgers, Daniela; Müller, Hans-Peter; Jacobs, Gunnar; Kassubek, Jan; Lieb, Wolfgang; Nöthlings, Ute

    2015-01-01

    Population-based evidence for the role of habitual physical activity (PA) in the accumulation of visceral (VAT) and subcutaneous (SAAT) abdominal adipose tissue is limited. We investigated if usual patterns and types of self-reported PA and inactivity were associated with VAT and SAAT in a general white population. Total volumes of VAT and SAAT were quantified by magnetic resonance imaging in 583 men and women (61 ± 11.9 y; BMI 27.2 ± 4.4 kg/m2). Past-year PA and inactivity were self-reported by questionnaire. Exploratory activity patterns (APAT) were derived by principal components analysis. Cross-sectional associations between individual activities, total PA in terms of metabolic equivalents (PA MET), or overall APAT and either VAT or SAAT were analyzed by multivariable-adjusted robust or generalized linear regression models. Whereas vigorous-intensity PA (VPA) was negatively associated with both VAT and SAAT, associations between total PA MET, moderate-intensity PA (MPA), or inactivity and VAT and/or SAAT depended on sex. There was also evidence of a threshold effect in some of these relationships. Total PA MET was more strongly associated with VAT in men (B = -3.3 ± 1.4; P = 0.02) than women (B = -2.1 ± 1.1; P = 0.07), but was more strongly associated with SAAT in women (B = -5.7 ± 2.5; P = 0.05) than men (B = -1.7 ± 1.6; P = 0.3). Men (-1.52 dm3 or -1.89 dm3) and women (-1.15 dm3 or -2.61 dm3) in the highest (>6.8 h/wk VPA) or second (4.0-6.8 h/wk VPA) tertile of an APAT rich in VPA, had lower VAT and SAAT, respectively, than those in the lowest (<4.0 h/wk VPA) tertile (P ≤ 0.016; P trend ≤ 0.0005). They also had lower VAT and SAAT than those with APAT rich in MPA and/or inactivity only. In conclusion, our results suggest that in white populations, habitual APAT rich in MPA might be insufficient to impact on accumulation of VAT or SAAT. APAT including ≥ 4.0-6.8 h/wk VPA, by contrast, are more strongly associated with lower VAT and SAAT.

  4. The World Population Dilemma.

    ERIC Educational Resources Information Center

    Population Reference Bureau, Inc., Washington, DC.

    This book is the third in a series published by the Population Reference Bureau aimed at illuminating the facts and consequences of human population dynamics for secondary and college-age students. Many illustrations, charts and graphs are included in this volume to help the reader grasp a number of the current ideas and concepts that are used in…

  5. Quantitative assessment of MS plaques and brain atrophy in multiple sclerosis using semiautomatic segmentation method

    NASA Astrophysics Data System (ADS)

    Heinonen, Tomi; Dastidar, Prasun; Ryymin, Pertti; Lahtinen, Antti J.; Eskola, Hannu; Malmivuo, Jaakko

    1997-05-01

    Quantitative magnetic resonance (MR) imaging of the brain is useful in multiple sclerosis (MS) in order to obtain reliable indices of disease progression. The goal of this project was to estimate the total volume of gliotic and non gliotic plaques in chronic progressive multiple sclerosis with the help of a semiautomatic segmentation method developed at the Ragnar Granit Institute. Youth developed program running on a PC based computer provides de displays of the segmented data, in addition to the volumetric analyses. The volumetric accuracy of the program was demonstrated by segmenting MR images of fluid filed syringes. An anatomical atlas is to be incorporated in the segmentation system to estimate the distribution of MS plaques in various neural pathways of the brain. A total package including MS plaque volume estimation, estimation of brain atrophy and ventricular enlargement, distribution of MS plaques in different neural segments of the brain has ben planned for the near future. Our study confirmed that total lesion volumes in chronic MS disease show a poor correlation to EDSS scores but show a positive correlation to neuropsychological scores. Therefore accurate total volume measurements of MS plaques using the developed semiautomatic segmentation technique helped us to evaluate the degree of neuropsychological impairment.

  6. Segmentation of knee MRI using structure enhanced local phase filtering

    NASA Astrophysics Data System (ADS)

    Lim, Mikhiel; Hacihaliloglu, Ilker

    2016-03-01

    The segmentation of bone surfaces from magnetic resonance imaging (MRI) data has applications in the quanti- tative measurement of knee osteoarthritis, surgery planning for patient specific total knee arthroplasty and its subsequent fabrication of artificial implants. However, due to the problems associated with MRI imaging such as low contrast between bone and surrounding tissues, noise, bias fields, and the partial volume effect, segmentation of bone surfaces continues to be a challenging operation. In this paper, a new framework is presented for the enhancement of knee MRI scans prior to segmentation in order to obtain high contrast bone images. During the first stage, a new contrast enhanced relative total variation (RTV) regularization method is used in order to remove textural noise from the bone structures and surrounding soft tissue interface. This salient bone edge information is further enhanced using a sparse gradient counting method based on L0 gradient minimization, which globally controls how many non-zero gradients are resulted in order to approximate prominent bone structures in a structure-sparsity-management manner. The last stage of the framework involves incorporation of local phase bone boundary information in order to provide an intensity invariant enhancement of contrast between the bone and surrounding soft tissue. The enhanced images are segmented using a fast random walker algorithm. Validation against expert segmentation was performed on 10 clinical knee MRI images, and achieved a mean dice similarity coefficient (DSC) of 0.975.

  7. Segmentation and detection of fluorescent 3D spots.

    PubMed

    Ram, Sundaresh; Rodríguez, Jeffrey J; Bosco, Giovanni

    2012-03-01

    The 3D spatial organization of genes and other genetic elements within the nucleus is important for regulating gene expression. Understanding how this spatial organization is established and maintained throughout the life of a cell is key to elucidating the many layers of gene regulation. Quantitative methods for studying nuclear organization will lead to insights into the molecular mechanisms that maintain gene organization as well as serve as diagnostic tools for pathologies caused by loss of nuclear structure. However, biologists currently lack automated and high throughput methods for quantitative and qualitative global analysis of 3D gene organization. In this study, we use confocal microscopy and fluorescence in-situ hybridization (FISH) as a cytogenetic technique to detect and localize the presence of specific DNA sequences in 3D. FISH uses probes that bind to specific targeted locations on the chromosomes, appearing as fluorescent spots in 3D images obtained using fluorescence microscopy. In this article, we propose an automated algorithm for segmentation and detection of 3D FISH spots. The algorithm is divided into two stages: spot segmentation and spot detection. Spot segmentation consists of 3D anisotropic smoothing to reduce the effect of noise, top-hat filtering, and intensity thresholding, followed by 3D region-growing. Spot detection uses a Bayesian classifier with spot features such as volume, average intensity, texture, and contrast to detect and classify the segmented spots as either true or false spots. Quantitative assessment of the proposed algorithm demonstrates improved segmentation and detection accuracy compared to other techniques.

  8. Improving vertebra segmentation through joint vertebra-rib atlases

    NASA Astrophysics Data System (ADS)

    Wang, Yinong; Yao, Jianhua; Roth, Holger R.; Burns, Joseph E.; Summers, Ronald M.

    2016-03-01

    Accurate spine segmentation allows for improved identification and quantitative characterization of abnormalities of the vertebra, such as vertebral fractures. However, in existing automated vertebra segmentation methods on computed tomography (CT) images, leakage into nearby bones such as ribs occurs due to the close proximity of these visibly intense structures in a 3D CT volume. To reduce this error, we propose the use of joint vertebra-rib atlases to improve the segmentation of vertebrae via multi-atlas joint label fusion. Segmentation was performed and evaluated on CTs containing 106 thoracic and lumbar vertebrae from 10 pathological and traumatic spine patients on an individual vertebra level basis. Vertebra atlases produced errors where the segmentation leaked into the ribs. The use of joint vertebra-rib atlases produced a statistically significant increase in the Dice coefficient from 92.5 +/- 3.1% to 93.8 +/- 2.1% for the left and right transverse processes and a decrease in the mean and max surface distance from 0.75 +/- 0.60mm and 8.63 +/- 4.44mm to 0.30 +/- 0.27mm and 3.65 +/- 2.87mm, respectively.

  9. Automated Segmentation of Soils Using X-ray Tomography

    NASA Astrophysics Data System (ADS)

    Miller, M.; Miller, E.; McKinley, J.

    2014-12-01

    X-ray tomography (CT) has long been a useful tool for three-dimensional imaging of compositionally heterogeneous objects. In the environmental sciences, CT is an efficient tool for the nondestructive inspection of sediment and soil cores. However, in order to extract parameters describing such properties as pore space and solid-phase distribution, the imaged volume must be segmented according to relevant categories. When done manually by image inspection, segmentation produces results that are often inconsistent, and applying the method over multiple images may be impractical. Modern machine learning techniques have been shown to be more accurate than humans at some vision tasks in fields of histology and remote sensing, and those techniques may be useful for environmental samples. We present a technique using deep learning to categorize a tomographic volume into solid and pore regions, while also identifying morphologically similar solid-phase regions within the imaged object. Finally, we show how the composition of these characteristic solid constituents may be estimated by propagating two dimensional XRF data through the segmented volume. This research was funded by the Chemical Imaging Initiative under the Laboratory Directed Research and Development Program at PNNL.

  10. Classifiers for Ischemic Stroke Lesion Segmentation: A Comparison Study

    PubMed Central

    Maier, Oskar; Schröder, Christoph; Forkert, Nils Daniel; Martinetz, Thomas; Handels, Heinz

    2015-01-01

    Motivation Ischemic stroke, triggered by an obstruction in the cerebral blood supply, leads to infarction of the affected brain tissue. An accurate and reproducible automatic segmentation is of high interest, since the lesion volume is an important end-point for clinical trials. However, various factors, such as the high variance in lesion shape, location and appearance, render it a difficult task. Methods In this article, nine classification methods (e.g. Generalized Linear Models, Random Decision Forests and Convolutional Neural Networks) are evaluated and compared with each other using 37 multiparametric MRI datasets of ischemic stroke patients in the sub-acute phase in terms of their accuracy and reliability for ischemic stroke lesion segmentation. Within this context, a multi-spectral classification approach is compared against mono-spectral classification performance using only FLAIR MRI datasets and two sets of expert segmentations are used for inter-observer agreement evaluation. Results and Conclusion The results of this study reveal that high-level machine learning methods lead to significantly better segmentation results compared to the rather simple classification methods, pointing towards a difficult non-linear problem. The overall best segmentation results were achieved by a Random Decision Forest and a Convolutional Neural Networks classification approach, even outperforming all previously published results. However, none of the methods tested in this work are capable of achieving results in the range of the human observer agreement and the automatic ischemic stroke lesion segmentation remains a complicated problem that needs to be explored in more detail to improve the segmentation results. PMID:26672989

  11. Automatic segmentation of psoriasis lesions

    NASA Astrophysics Data System (ADS)

    Ning, Yang; Shi, Chenbo; Wang, Li; Shu, Chang

    2014-10-01

    The automatic segmentation of psoriatic lesions is widely researched these years. It is an important step in Computer-aid methods of calculating PASI for estimation of lesions. Currently those algorithms can only handle single erythema or only deal with scaling segmentation. In practice, scaling and erythema are often mixed together. In order to get the segmentation of lesions area - this paper proposes an algorithm based on Random forests with color and texture features. The algorithm has three steps. The first step, the polarized light is applied based on the skin's Tyndall-effect in the imaging to eliminate the reflection and Lab color space are used for fitting the human perception. The second step, sliding window and its sub windows are used to get textural feature and color feature. In this step, a feature of image roughness has been defined, so that scaling can be easily separated from normal skin. In the end, Random forests will be used to ensure the generalization ability of the algorithm. This algorithm can give reliable segmentation results even the image has different lighting conditions, skin types. In the data set offered by Union Hospital, more than 90% images can be segmented accurately.

  12. Optimal segmentation and packaging process

    DOEpatents

    Kostelnik, K.M.; Meservey, R.H.; Landon, M.D.

    1999-08-10

    A process for improving packaging efficiency uses three dimensional, computer simulated models with various optimization algorithms to determine the optimal segmentation process and packaging configurations based on constraints including container limitations. The present invention is applied to a process for decontaminating, decommissioning (D and D), and remediating a nuclear facility involving the segmentation and packaging of contaminated items in waste containers in order to minimize the number of cuts, maximize packaging density, and reduce worker radiation exposure. A three-dimensional, computer simulated, facility model of the contaminated items are created. The contaminated items are differentiated. The optimal location, orientation and sequence of the segmentation and packaging of the contaminated items is determined using the simulated model, the algorithms, and various constraints including container limitations. The cut locations and orientations are transposed to the simulated model. The contaminated items are actually segmented and packaged. The segmentation and packaging may be simulated beforehand. In addition, the contaminated items may be cataloged and recorded. 3 figs.

  13. Image Information Mining Utilizing Hierarchical Segmentation

    NASA Technical Reports Server (NTRS)

    Tilton, James C.; Marchisio, Giovanni; Koperski, Krzysztof; Datcu, Mihai

    2002-01-01

    The Hierarchical Segmentation (HSEG) algorithm is an approach for producing high quality, hierarchically related image segmentations. The VisiMine image information mining system utilizes clustering and segmentation algorithms for reducing visual information in multispectral images to a manageable size. The project discussed herein seeks to enhance the VisiMine system through incorporating hierarchical segmentations from HSEG into the VisiMine system.

  14. Identifying Benefit Segments among College Students.

    ERIC Educational Resources Information Center

    Brown, Joseph D.

    1991-01-01

    Using concept of market segmentation (dividing market into distinct groups requiring different product benefits), surveyed 398 college students to determine benefit segments among students selecting a college to attend and factors describing each benefit segment. Identified one major segment of students (classroomers) plus three minor segments…

  15. 47 CFR 95.853 - Frequency segments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Frequency segments. 95.853 Section 95.853... SERVICES 218-219 MHz Service Technical Standards § 95.853 Frequency segments. There are two frequency segments available for assignment to the 218-219 MHz Service in each service area. Frequency segment A...

  16. 47 CFR 95.853 - Frequency segments.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Frequency segments. 95.853 Section 95.853... SERVICES 218-219 MHz Service Technical Standards § 95.853 Frequency segments. There are two frequency segments available for assignment to the 218-219 MHz Service in each service area. Frequency segment A...

  17. 47 CFR 95.853 - Frequency segments.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Frequency segments. 95.853 Section 95.853... SERVICES 218-219 MHz Service Technical Standards § 95.853 Frequency segments. There are two frequency segments available for assignment to the 218-219 MHz Service in each service area. Frequency segment A...

  18. 47 CFR 95.853 - Frequency segments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Frequency segments. 95.853 Section 95.853... SERVICES 218-219 MHz Service Technical Standards § 95.853 Frequency segments. There are two frequency segments available for assignment to the 218-219 MHz Service in each service area. Frequency segment A...

  19. 47 CFR 95.853 - Frequency segments.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Frequency segments. 95.853 Section 95.853... SERVICES 218-219 MHz Service Technical Standards § 95.853 Frequency segments. There are two frequency segments available for assignment to the 218-219 MHz Service in each service area. Frequency segment A...

  20. Ground Water Atlas of the United States: Segment 8, Montana, North Dakota, South Dakota, Wyoming

    USGS Publications Warehouse

    Whitehead, R.L.

    1996-01-01

    completed in semiconsolidated- and consolidated-rock aquifers, chiefly sandstone and limestone. Some wells withdraw water from volcanic rocks, igneous and metamorphic rocks, or fractured fine-grained sedimentary rocks, such as shale; however, wells completed in these types of rocks generally yield only small volumes of water. Most wells in the four-State area of Segment 8 are on privately owned land (fig. 2). Agriculture, primarily irrigation, is one of the largest uses of ground water. The irrigation generally is on lowlands close to streams (fig. 3). Lowlands within a few miles of major streams usually are irrigated with surface water that is diverted by gravity flow from the main stream or a reservoir and transported through a canal system. Surface water also is pumped to irrigate land that gravity systems cannot supply. In addition, ground water is pumped from large-capacity wells to supplement surface water during times of drought or during seasons of the year when surface water is in short supply. Ground water is the only source of water for irrigation in much of the segment. The thickness and permeability of aquifers in the area of Segment 8 vary considerably, as do yields of wells completed in the aquifers. Ground-water levels and artesian pressures (hydraulic head) have declined significantly in some places as a result of excessive withdrawals by wells. State governments have taken steps to control the declines by enacting programs that either limit the number of additional wells that can be completed in a particular aquifer or prevent further ground-water development altogether. The demand for water is directly related to the distribution of people. In 1990, Montana had a population of 799,065; North Dakota, 638,800; South Dakota, 696,004; and Wyoming, 453,588. The more densely populated areas are on lowlands near major streams. Many of the mountain, desert, and upland areas lack major population centers, particularly in Montana and Wyoming, where use

  1. Ureter tracking and segmentation in CT urography (CTU) using COMPASS

    SciTech Connect

    Hadjiiski, Lubomir Zick, David; Chan, Heang-Ping; Cohan, Richard H.; Caoili, Elaine M.; Cha, Kenny; Zhou, Chuan; Wei, Jun

    2014-12-15

    Purpose: The authors are developing a computerized system for automated segmentation of ureters in CTU, referred to as combined model-guided path-finding analysis and segmentation system (COMPASS). Ureter segmentation is a critical component for computer-aided diagnosis of ureter cancer. Methods: COMPASS consists of three stages: (1) rule-based adaptive thresholding and region growing, (2) path-finding and propagation, and (3) edge profile extraction and feature analysis. With institutional review board approval, 79 CTU scans performed with intravenous (IV) contrast material enhancement were collected retrospectively from 79 patient files. One hundred twenty-four ureters were selected from the 79 CTU volumes. On average, the ureters spanned 283 computed tomography slices (range: 116–399, median: 301). More than half of the ureters contained malignant or benign lesions and some had ureter wall thickening due to malignancy. A starting point for each of the 124 ureters was identified manually to initialize the tracking by COMPASS. In addition, the centerline of each ureter was manually marked and used as reference standard for evaluation of tracking performance. The performance of COMPASS was quantitatively assessed by estimating the percentage of the length that was successfully tracked and segmented for each ureter and by estimating the average distance and the average maximum distance between the computer and the manually tracked centerlines. Results: Of the 124 ureters, 120 (97%) were segmented completely (100%), 121 (98%) were segmented through at least 70%, and 123 (99%) were segmented through at least 50% of its length. In comparison, using our previous method, 85 (69%) ureters were segmented completely (100%), 100 (81%) were segmented through at least 70%, and 107 (86%) were segmented at least 50% of its length. With COMPASS, the average distance between the computer and the manually generated centerlines is 0.54 mm, and the average maximum distance is 2

  2. Segmentation of perivascular spaces in 7T MR image using auto-context model with orientation-normalized features.

    PubMed

    Park, Sang Hyun; Zong, Xiaopeng; Gao, Yaozong; Lin, Weili; Shen, Dinggang

    2016-07-01

    Quantitative study of perivascular spaces (PVSs) in brain magnetic resonance (MR) images is important for understanding the brain lymphatic system and its relationship with neurological diseases. One of the major challenges is the accurate extraction of PVSs that have very thin tubular structures with various directions in three-dimensional (3D) MR images. In this paper, we propose a learning-based PVS segmentation method to address this challenge. Specifically, we first determine a region of interest (ROI) by using the anatomical brain structure and the vesselness information derived from eigenvalues of image derivatives. Then, in the ROI, we extract a number of randomized Haar features which are normalized with respect to the principal directions of the underlying image derivatives. The classifier is trained by the random forest model that can effectively learn both discriminative features and classifier parameters to maximize the information gain. Finally, a sequential learning strategy is used to further enforce various contextual patterns around the thin tubular structures into the classifier. For evaluation, we apply our proposed method to the 7T brain MR images scanned from 17 healthy subjects aged from 25 to 37. The performance is measured by voxel-wise segmentation accuracy, cluster-wise classification accuracy, and similarity of geometric properties, such as volume, length, and diameter distributions between the predicted and the true PVSs. Moreover, the accuracies are also evaluated on the simulation images with motion artifacts and lacunes to demonstrate the potential of our method in segmenting PVSs from elderly and patient populations. The experimental results show that our proposed method outperforms all existing PVS segmentation methods. PMID:27046107

  3. Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

    NASA Astrophysics Data System (ADS)

    Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

    2015-03-01

    Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

  4. Nanofiber-segment ring resonator

    NASA Astrophysics Data System (ADS)

    Jones, D. E.; Hickman, G. T.; Franson, J. D.; Pittman, T. B.

    2016-08-01

    We describe a fiber ring resonator comprised of a relatively long loop of standard single-mode fiber with a short nanofiber segment. The evanescent mode of the nanofiber segment allows the cavity-enhanced field to interact with atoms in close proximity to the nanofiber surface. We report on an experiment using a warm atomic vapor and low-finesse cavity, and briefly discuss the potential for reaching the strong coupling regime of cavity QED by using trapped atoms and a high-finesse cavity of this kind.

  5. Document segmentation via oblique cuts

    NASA Astrophysics Data System (ADS)

    Svendsen, Jeremy; Branzan-Albu, Alexandra

    2013-01-01

    This paper presents a novel solution for the layout segmentation of graphical elements in Business Intelligence documents. We propose a generalization of the recursive X-Y cut algorithm, which allows for cutting along arbitrary oblique directions. An intermediate processing step consisting of line and solid region removal is also necessary due to presence of decorative elements. The output of the proposed segmentation is a hierarchical structure which allows for the identification of primitives in pie and bar charts. The algorithm was tested on a database composed of charts from business documents. Results are very promising.

  6. Reaching the Non-Traditional Stopout Population: A Segmentation Approach

    ERIC Educational Resources Information Center

    Schatzel, Kim; Callahan, Thomas; Scott, Crystal J.; Davis, Timothy

    2011-01-01

    An estimated 21% of 25-34-year-olds in the United States, about eight million individuals, have attended college and quit before completing a degree. These non-traditional students may or may not return to college. Those who return to college are referred to as stopouts, whereas those who do not return are referred to as stayouts. In the face of…

  7. Conflation of Short Identity-by-Descent Segments Bias Their Inferred Length Distribution.

    PubMed

    Chiang, Charleston W K; Ralph, Peter; Novembre, John

    2016-01-01

    Identity-by-descent (IBD) is a fundamental concept in genetics with many applications. In a common definition, two haplotypes are said to share an IBD segment if that segment is inherited from a recent shared common ancestor without intervening recombination. Segments several cM long can be efficiently detected by a number of algorithms using high-density SNP array data from a population sample, and there are currently efforts to detect shorter segments from sequencing. Here, we study a problem of identifiability: because existing approaches detect IBD based on contiguous segments of identity-by-state, inferred long segments of IBD may arise from the conflation of smaller, nearby IBD segments. We quantified this effect using coalescent simulations, finding that significant proportions of inferred segments 1-2 cM long are results of conflations of two or more shorter segments, each at least 0.2 cM or longer, under demographic scenarios typical for modern humans for all programs tested. The impact of such conflation is much smaller for longer (> 2 cM) segments. This biases the inferred IBD segment length distribution, and so can affect downstream inferences that depend on the assumption that each segment of IBD derives from a single common ancestor. As an example, we present and analyze an estimator of the de novo mutation rate using IBD segments, and demonstrate that unmodeled conflation leads to underestimates of the ages of the common ancestors on these segments, and hence a significant overestimate of the mutation rate. Understanding the conflation effect in detail will make its correction in future methods more tractable.

  8. Conflation of Short Identity-by-Descent Segments Bias Their Inferred Length Distribution

    PubMed Central

    Chiang, Charleston W. K.; Ralph, Peter; Novembre, John

    2016-01-01

    Identity-by-descent (IBD) is a fundamental concept in genetics with many applications. In a common definition, two haplotypes are said to share an IBD segment if that segment is inherited from a recent shared common ancestor without intervening recombination. Segments several cM long can be efficiently detected by a number of algorithms using high-density SNP array data from a population sample, and there are currently efforts to detect shorter segments from sequencing. Here, we study a problem of identifiability: because existing approaches detect IBD based on contiguous segments of identity-by-state, inferred long segments of IBD may arise from the conflation of smaller, nearby IBD segments. We quantified this effect using coalescent simulations, finding that significant proportions of inferred segments 1–2 cM long are results of conflations of two or more shorter segments, each at least 0.2 cM or longer, under demographic scenarios typical for modern humans for all programs tested. The impact of such conflation is much smaller for longer (> 2 cM) segments. This biases the inferred IBD segment length distribution, and so can affect downstream inferences that depend on the assumption that each segment of IBD derives from a single common ancestor. As an example, we present and analyze an estimator of the de novo mutation rate using IBD segments, and demonstrate that unmodeled conflation leads to underestimates of the ages of the common ancestors on these segments, and hence a significant overestimate of the mutation rate. Understanding the conflation effect in detail will make its correction in future methods more tractable. PMID:26935417

  9. Reassortment and distinct evolutionary dynamics of Rift Valley Fever virus genomic segments

    PubMed Central

    Freire, Caio C. M.; Iamarino, Atila; Soumaré, Peinda O. Ly; Faye, Ousmane; Sall, Amadou A.; Zanotto, Paolo M. A.

    2015-01-01

    Rift Valley Fever virus (RVFV) is a member of Bunyaviridae family that causes a febrile disease affecting mainly ruminants and occasionally humans in Africa, with symptoms that range from mid to severe. RVFV has a tri-segmented ssRNA genome that permits reassortment and could generate more virulent strains. In this study, we reveal the importance of reassortment for RVFV evolution using viral gene genealogy inference and phylodynamics. We uncovered seven events of reassortment that originated RVFV lineages with discordant origins among segments. Moreover, we also found that despite similar selection regimens, the three segments have distinct evolutionary dynamics; the longer segment L evolves at a significant lower rate. Episodes of discordance between population size estimates per segment also coincided with reassortment dating. Our results show that RVFV segments are decoupled enough to have distinct demographic histories and to evolve under different molecular rates. PMID:26100494

  10. Reassortment and distinct evolutionary dynamics of Rift Valley Fever virus genomic segments.

    PubMed

    Freire, Caio C M; Iamarino, Atila; Soumaré, Peinda O Ly; Faye, Ousmane; Sall, Amadou A; Zanotto, Paolo M A

    2015-01-01

    Rift Valley Fever virus (RVFV) is a member of Bunyaviridae family that causes a febrile disease affecting mainly ruminants and occasionally humans in Africa, with symptoms that range from mid to severe. RVFV has a tri-segmented ssRNA genome that permits reassortment and could generate more virulent strains. In this study, we reveal the importance of reassortment for RVFV evolution using viral gene genealogy inference and phylodynamics. We uncovered seven events of reassortment that originated RVFV lineages with discordant origins among segments. Moreover, we also found that despite similar selection regimens, the three segments have distinct evolutionary dynamics; the longer segment L evolves at a significant lower rate. Episodes of discordance between population size estimates per segment also coincided with reassortment dating. Our results show that RVFV segments are decoupled enough to have distinct demographic histories and to evolve under different molecular rates. PMID:26100494

  11. Reproducibility of MRI segmentation using a feature space method

    NASA Astrophysics Data System (ADS)

    Soltanian-Zadeh, Hamid; Windham, Joe P.; Scarpace, Lisa; Murnock, Tanya

    1998-06-01

    This paper presents reproducibility studies for the segmentation results obtained by our optimal MRI feature space method. The steps of the work accomplished are as follows. (1) Eleven patients with brain tumors were imaged by a 1.5 T General Electric Signa MRI System. Four T2- weighted and two T1-weighted images (before and after Gadolinium injection) were acquired for each patient. (2) Images of a slice through the center of the tumor were selected for processing. (3) Patient information was removed from the image headers and new names (unrecognizable by the image analysts) were given to the images. These images were blindly analyzed by the image analysts. (4) Segmentation results obtained by the two image analysts at two time points were compared to assess the reproducibility of the segmentation method. For each tissue segmented in each patient study, a comparison was done by kappa statistics and a similarity measure (an approximation of kappa statistics used by other researchers), to evaluate the number of pixels that were in both of the segmentation results obtained by the two image analysts (agreement) relative to the number of pixels that were not in both (disagreement). An overall agreement comparison was done by finding means and standard deviations of kappa statistics and the similarity measure found for each tissue type in the studies. The kappa statistics for white matter was the largest (0.80) followed by those of gray matter (0.68), partial volume (0.67), total lesion (0.66), and CSF (0.44). The similarity measure showed the same trend but it was always higher than kappa statistics. It was 0.85 for white matter, 0.77 for gray matter, 0.73 for partial volume, 0.72 for total lesion, and 0.47 for CSF.

  12. Natural landscape and stream segment attributes influencing the distribution and relative abundance of riverine smallmouth bass in Missouri

    USGS Publications Warehouse

    Brewer, S.K.; Rabeni, C.F.; Sowa, S.P.; Annis, G.

    2007-01-01

    Protecting and restoring fish populations on a regional basis are most effective if the multiscale factors responsible for the relative quality of a fishery are known. We spatially linked Missouri's statewide historical fish collections to environmental features in a geographic information system, which was used as a basis for modeling the importance of landscape and stream segment features in supporting a population of smallmouth bass Micropterus dolomieu. Decision tree analyses were used to develop probability-based models to predict statewide occurrence and within-range relative abundances. We were able to identify the range of smallmouth bass throughout Missouri and the probability of occurrence within that range by using a few broad landscape variables: the percentage of coarse-textured soils in the watershed, watershed relief, and the percentage of soils with low permeability in the watershed. The within-range relative abundance model included both landscape and stream segment variables. As with the statewide probability of occurrence model, soil permeability was particularly significant. The predicted relative abundance of smallmouth bass in stream segments containing low percentages of permeable soils was further influenced by channel gradient, stream size, spring-flow volume, and local slope. Assessment of model accuracy with an independent data set showed good concordance. A conceptual framework involving naturally occurring factors that affect smallmouth bass potential is presented as a comparative model for assessing transferability to other geographic areas and for studying potential land use and biotic effects. We also identify the benefits, caveats, and data requirements necessary to improve predictions and promote ecological understanding. ?? Copyright by the American Fisheries Society 2007.

  13. Fast prostate segmentation for brachytherapy based on joint fusion of images and labels

    NASA Astrophysics Data System (ADS)

    Nouranian, Saman; Ramezani, Mahdi; Mahdavi, S. Sara; Spadinger, Ingrid; Morris, William J.; Salcudean, Septimiu E.; Abolmaesumi, Purang

    2014-03-01

    Brachytherapy as one of the treatment methods for prostate cancer takes place by implantation of radioactive seeds inside the gland. The standard of care for this treatment procedure is to acquire transrectal ultrasound images of the prostate which are segmented in order to plan the appropriate seed placement. The segmentation process is usually performed either manually or semi-automatically and is associated with subjective errors because the prostate visibility is limited in ultrasound images. The current segmentation process also limits the possibility of intra-operative delineation of the prostate to perform real-time dosimetry. In this paper, we propose a computationally inexpensive and fully automatic segmentation approach that takes advantage of previously segmented images to form a joint space of images and their segmentations. We utilize joint Independent Component Analysis method to generate a model which is further employed to produce a probability map of the target segmentation. We evaluate this approach on the transrectal ultrasound volume images of 60 patients using a leave-one-out cross-validation approach. The results are compared with the manually segmented prostate contours that were used by clinicians to plan brachytherapy procedures. We show that the proposed approach is fast with comparable accuracy and precision to those found in previous studies on TRUS segmentation.

  14. Age Differences in Language Segmentation.

    PubMed

    Stine-Morrow, Elizabeth A L; Payne, Brennan R

    2016-01-01

    Reading bears the evolutionary footprint of spoken communication. Prosodic contour in speech helps listeners parse sentences and establish semantic focus. Readers' regulation of input mirrors the segmentation patterns of prosody, such that reading times are longer for words at the ends of syntactic constituents. As reflected in these "micropauses," older readers are often found to segment text into smaller chunks. The mechanisms underlying these micropauses are unclear, with some arguing that they derive from the mental simulation of prosodic contour and others arguing they reflect higher-level language comprehension mechanisms (e.g., conceptual integration, consolidation with existing knowledge, ambiguity resolution) that are common across modality and support the consolidation of the memory representation. The authors review evidence based on reading time and comprehension performance to suggest that (a) age differences in segmentation derive both from age-related declines in working memory, as well as from crystallized ability and knowledge, which have the potential to grow in adulthood, and that (b) shifts in segmentation patterns may be a pathway through which language comprehension is preserved in late life.

  15. Segmentation in Urban Housing Markets.

    ERIC Educational Resources Information Center

    Schnare, Ann B.; Struyk, Raymond J.

    1976-01-01

    In this study, the hypothesis that urban housing markets are segmented, in the sense that significantly different prices per unit of housing services exist contemporaneously in spatially or structurally defined markets, is tested. A main conclusion is that the market is working fairly efficiently to eliminate price premiums and discounts.…

  16. Multiple Segment Factorial Vignette Designs

    ERIC Educational Resources Information Center

    Ganong, Lawrence H.; Coleman, Marilyn

    2006-01-01

    The multiple segment factorial vignette design (MSFV) combines elements of experimental designs and probability sampling with the inductive, exploratory approach of qualitative research. MSFVs allow researchers to investigate topics that may be hard to study because of ethical or logistical concerns. Participants are presented with short stories…

  17. An early temperature-sensitive period for the plasticity of segment number in the centipede Strigamia maritima.

    PubMed

    Vedel, Vincent; Apostolou, Zivkos; Arthur, Wallace; Akam, Michael; Brena, Carlo

    2010-01-01

    Geophilomorph centipedes show variation in segment number (a) between closely related species and (b) within and between populations of the same species. We have previously shown for a Scottish population of the coastal centipede Strigamia maritima that the temperature of embryonic development is one of the factors that affects the segment number of hatchlings, and hence of adults, as these animals grow epimorphically--that is, without postembryonic addition of segments. Here, we show, using temperature-shift experiments, that the main developmental period during which embryos are sensitive to environmental temperature is surprisingly early, during blastoderm formation and before, or very shortly after, the onset of segmentation.

  18. Human Perception in Segmentation of Sketches

    NASA Astrophysics Data System (ADS)

    Company, Pedro; Varley, Peter A. C.; Piquer, Ana; Vergara, Margarita; Sánchez-Rubio, Jaime

    In this paper, we study the segmentation of sketched engineering drawings into a set of straight and curved segments. Our immediate objective is to produce a benchmarking method for segmentation algorithms. The criterion is to minimise the differences between what the algorithm detects and what human beings perceive. We have created a set of sketched drawings and have asked people to segment them. By analysis of the produced segmentations, we have obtained the number and locations of the segmentation points which people perceive. Evidence collected during our experiments supports useful hypotheses, for example that not all kinds of segmentation points are equally difficult to perceive. The resulting methodology can be repeated with other drawings to obtain a set of sketches and segmentation data which could be used as a benchmark for segmentation algorithms, to evaluate their capability to emulate human perception of sketches.

  19. Metric Learning to Enhance Hyperspectral Image Segmentation

    NASA Technical Reports Server (NTRS)

    Thompson, David R.; Castano, Rebecca; Bue, Brian; Gilmore, Martha S.

    2013-01-01

    Unsupervised hyperspectral image segmentation can reveal spatial trends that show the physical structure of the scene to an analyst. They highlight borders and reveal areas of homogeneity and change. Segmentations are independently helpful for object recognition, and assist with automated production of symbolic maps. Additionally, a good segmentation can dramatically reduce the number of effective spectra in an image, enabling analyses that would otherwise be computationally prohibitive. Specifically, using an over-segmentation of the image instead of individual pixels can reduce noise and potentially improve the results of statistical post-analysis. In this innovation, a metric learning approach is presented to improve the performance of unsupervised hyperspectral image segmentation. The prototype demonstrations attempt a superpixel segmentation in which the image is conservatively over-segmented; that is, the single surface features may be split into multiple segments, but each individual segment, or superpixel, is ensured to have homogenous mineralogy.

  20. Segmentation and leaf sequencing for intensity modulated arc therapy

    SciTech Connect

    Gladwish, Adam; Oliver, Mike; Craig, Jeff; Chen, Jeff; Bauman, Glenn; Fisher, Barbara; Wong, Eugene

    2007-05-15

    A common method in generating intensity modulated radiation therapy (IMRT) plans consists of a three step process: an optimized fluence intensity map (IM) for each beam is generated via inverse planning, this IM is then segmented into discrete levels, and finally, the segmented map is translated into a set of MLC apertures via a leaf sequencing algorithm. To date, limited work has been done on this approach as it pertains to intensity modulated arc therapy (IMAT), specifically in regards to the latter two steps. There are two determining factors that separate IMAT segmentation and leaf sequencing from their IMRT equivalents: (1) the intrinsic 3D nature of the intensity maps (standard 2D maps plus the angular component), and (2) that the dynamic multileaf collimator (MLC) constraints be met using a minimum number of arcs. In this work, we illustrate a technique to create an IMAT plan that replicates Tomotherapy deliveries by applying IMAT specific segmentation and leaf-sequencing algorithms to Tomotherapy output sinograms. We propose and compare two alternative segmentation techniques, a clustering method, and a bottom-up segmentation method (BUS). We also introduce a novel IMAT leaf-sequencing algorithm that explicitly takes leaf movement constraints into consideration. These algorithms were tested with 51 angular projections of the output leaf-open sinograms generated on the Hi-ART II treatment planning system (Tomotherapy Inc.). We present two geometric phantoms and 2 clinical scenarios as sample test cases. In each case 12 IMAT plans were created, ranging from 2 to 7 intensity levels. Half were generated using the BUS segmentation and half with the clustering method. We report on the number of arcs produced as well as differences between Tomotherapy output sinograms and segmented IMAT intensity maps. For each case one plan for each segmentation method is chosen for full Monte Carlo dose calculation (NumeriX LLC) and dose volume histograms (DVH) are calculated

  1. 3D transrectal ultrasound (TRUS) prostate segmentation based on optimal feature learning framework

    NASA Astrophysics Data System (ADS)

    Yang, Xiaofeng; Rossi, Peter J.; Jani, Ashesh B.; Mao, Hui; Curran, Walter J.; Liu, Tian

    2016-03-01

    We propose a 3D prostate segmentation method for transrectal ultrasound (TRUS) images, which is based on patch-based feature learning framework. Patient-specific anatomical features are extracted from aligned training images and adopted as signatures for each voxel. The most robust and informative features are identified by the feature selection process to train the kernel support vector machine (KSVM). The well-trained SVM was used to localize the prostate of the new patient. Our segmentation technique was validated with a clinical study of 10 patients. The accuracy of our approach was assessed using the manual segmentations (gold standard). The mean volume Dice overlap coefficient was 89.7%. In this study, we have developed a new prostate segmentation approach based on the optimal feature learning framework, demonstrated its clinical feasibility, and validated its accuracy with manual segmentations.

  2. Low-intensity daily walking activity is associated with hippocampal volume in older adults.

    PubMed

    Varma, Vijay R; Chuang, Yi-Fang; Harris, Gregory C; Tan, Erwin J; Carlson, Michelle C

    2015-05-01

    Hippocampal atrophy is associated with memory impairment and dementia and serves as a key biomarker in the preclinical stages of Alzheimer's disease. Physical activity, one of the most promising behavioral interventions to prevent or delay cognitive decline, has been shown to be associated with hippocampal volume; specifically increased aerobic activity and fitness may have a positive effect on the size of the hippocampus. The majority of older adults, however, are sedentary and have difficulty initiating and maintaining exercise programs. A modestly more active lifestyle may nonetheless be beneficial. This study explored whether greater objectively measured daily walking activity was associated with larger hippocampal volume. We additionally explored whether greater low-intensity walking activity, which may be related to leisure-time physical, functional, and social activities, was associated with larger hippocampal volume independent of exercise and higher-intensity walking activity. Segmentation of hippocampal volumes was performed using Functional Magnetic Resonance Imaging of the Brain's Software Library (FSL), and daily walking activity was assessed using a step activity monitor on 92, nondemented, older adult participants. After controlling for age, education, body mass index, cardiovascular disease risk factors, and the Mini Mental State Exam, we found that a greater amount, duration, and frequency of total daily walking activity were each associated with larger hippocampal volume among older women, but not among men. These relationships were specific to hippocampal volume, compared with the thalamus, used as a control brain region, and remained significant for low-intensity walking activity, independent of moderate- to vigorous-intensity activity and self-reported exercise. This is the first study, to our knowledge, to explore the relationship between objectively measured daily walking activity and hippocampal volume in an older adult population. Findings

  3. Automatic segmentation of vertebral arteries in CT angiography using combined circular and cylindrical model fitting

    NASA Astrophysics Data System (ADS)

    Lee, Min Jin; Hong, Helen; Chung, Jin Wook

    2014-03-01

    We propose an automatic vessel segmentation method of vertebral arteries in CT angiography using combined circular and cylindrical model fitting. First, to generate multi-segmented volumes, whole volume is automatically divided into four segments by anatomical properties of bone structures along z-axis of head and neck. To define an optimal volume circumscribing vertebral arteries, anterior-posterior bounding and side boundaries are defined as initial extracted vessel region. Second, the initial vessel candidates are tracked using circular model fitting. Since boundaries of the vertebral arteries are ambiguous in case the arteries pass through the transverse foramen in the cervical vertebra, the circle model is extended along z-axis to cylinder model for considering additional vessel information of neighboring slices. Finally, the boundaries of the vertebral arteries are detected using graph-cut optimization. From the experiments, the proposed method provides accurate results without bone artifacts and eroded vessels in the cervical vertebra.

  4. Segment Specification for the Payload Segment of the Reusable Reentry Satellite: Rodent Module Version

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

  5. Volumetric CT-based segmentation of NSCLC using 3D-Slicer.

    PubMed

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H; van Baardwijk, Angela; Fennessy, Fiona M; Lewis, John H; De Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J W L

    2013-01-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the "gold standard". The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81-0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck. PMID:24346241

  6. Automatic segmentation of brain MRIs and mapping neuroanatomy across the human lifespan

    NASA Astrophysics Data System (ADS)

    Keihaninejad, Shiva; Heckemann, Rolf A.; Gousias, Ioannis S.; Rueckert, Daniel; Aljabar, Paul; Hajnal, Joseph V.; Hammers, Alexander

    2009-02-01

    A robust model for the automatic segmentation of human brain images into anatomically defined regions across the human lifespan would be highly desirable, but such structural segmentations of brain MRI are challenging due to age-related changes. We have developed a new method, based on established algorithms for automatic segmentation of young adults' brains. We used prior information from 30 anatomical atlases, which had been manually segmented into 83 anatomical structures. Target MRIs came from 80 subjects (~12 individuals/decade) from 20 to 90 years, with equal numbers of men, women; data from two different scanners (1.5T, 3T), using the IXI database. Each of the adult atlases was registered to each target MR image. By using additional information from segmentation into tissue classes (GM, WM and CSF) to initialise the warping based on label consistency similarity before feeding this into the previous normalised mutual information non-rigid registration, the registration became robust enough to accommodate atrophy and ventricular enlargement with age. The final segmentation was obtained by combination of the 30 propagated atlases using decision fusion. Kernel smoothing was used for modelling the structural volume changes with aging. Example linear correlation coefficients with age were, for lateral ventricular volume, rmale=0.76, rfemale=0.58 and, for hippocampal volume, rmale=-0.6, rfemale=-0.4 (allρ<0.01).

  7. NeuroBlocks--Visual Tracking of Segmentation and Proofreading for Large Connectomics Projects.

    PubMed

    Ai-Awami, Ali K; Beyer, Johanna; Haehn, Daniel; Kasthuri, Narayanan; Lichtman, Jeff W; Pfister, Hanspeter; Hadwiger, Markus

    2016-01-01

    In the field of connectomics, neuroscientists acquire electron microscopy volumes at nanometer resolution in order to reconstruct a detailed wiring diagram of the neurons in the brain. The resulting image volumes, which often are hundreds of terabytes in size, need to be segmented to identify cell boundaries, synapses, and important cell organelles. However, the segmentation process of a single volume is very complex, time-intensive, and usually performed using a diverse set of tools and many users. To tackle the associated challenges, this paper presents NeuroBlocks, which is a novel visualization system for tracking the state, progress, and evolution of very large volumetric segmentation data in neuroscience. NeuroBlocks is a multi-user web-based application that seamlessly integrates the diverse set of tools that neuroscientists currently use for manual and semi-automatic segmentation, proofreading, visualization, and analysis. NeuroBlocks is the first system that integrates this heterogeneous tool set, providing crucial support for the management, provenance, accountability, and auditing of large-scale segmentations. We describe the design of NeuroBlocks, starting with an analysis of the domain-specific tasks, their inherent challenges, and our subsequent task abstraction and visual representation. We demonstrate the utility of our design based on two case studies that focus on different user roles and their respective requirements for performing and tracking the progress of segmentation and proofreading in a large real-world connectomics project.

  8. Model-based 3-D segmentation of multiple sclerosis lesions in dual-echo MRI data

    NASA Astrophysics Data System (ADS)

    Kamber, Micheline; Collins, D. Louis; Shinghal, Rajjan; Francis, G. S.; Evans, Alan C.

    1992-09-01

    This paper describes the development and use of a brain tissue probability model for the segmentation of multiple sclerosis lesions in magnetic resonance (MR) images of the human brain. Based on MR data obtained from a group of healthy volunteers, the model was constructed to provide prior probabilities of grey matter, white matter, ventricular cerebrospinal fluid (CSF), and external CSF distribution per unit voxel in a standardized 3- dimensional `brain space.' In comparison to purely data-driven segmentation, the use of the model to guide the segmentation of multiple sclerosis lesions reduced the volume of false positive lesions by 50%.

  9. Electro-Optic Segment-Segment Sensors for Radio and Optical Telescopes

    NASA Technical Reports Server (NTRS)

    Abramovici, Alex

    2012-01-01

    A document discusses an electro-optic sensor that consists of a collimator, attached to one segment, and a quad diode, attached to an adjacent segment. Relative segment-segment motion causes the beam from the collimator to move across the quad diode, thus generating a measureable electric signal. This sensor type, which is relatively inexpensive, can be configured as an edge sensor, or as a remote segment-segment motion sensor.

  10. Segmentation of elastic organs using region growing

    NASA Astrophysics Data System (ADS)

    Widita, R.; Kurniadi, R.; Darma, Y.; Perkasa, Y. S.; Trianti, N.

    2012-06-01

    We have been successfully developed a new software for image segmentation This software is addressed to do segmentation of elastic organs. The segmentation components used in this software is region growing algorithms which have proven to be an effective approach for image segmentation. The implementations of region growing developed here are connected threshold and neighborhood connected. The results show that the neighborhood algorithm affects the smoothness of the segmented object borders, the size of the segmented region, and reduces computing time. Our method is designed to perform with clinically acceptable speed, using accelerated techniques.

  11. Development of limb volume measuring system

    NASA Technical Reports Server (NTRS)

    Bhagat, P. K.; Kadaba, P. K.

    1983-01-01

    The mechanisms underlying the reductions in orthostatic tolerance associated with weightlessness are not well established. Contradictory results from measurements of leg volume changes suggest that altered venomotor tone and reduced blood flow may not be the only contributors to orthostatic intolerance. It is felt that a more accurate limb volume system which is insensitive to environmental factors will aid in better quantification of the hemodynamics of the leg. Of the varous limb volume techniques presently available, the ultrasonic limb volume system has proven to be the best choice. The system as described herein is free from environmental effects, safe, simple to operate and causes negligible radio frequency interference problems. The segmental ultrasonic ultrasonic plethysmograph is expected to provide a better measurement of limb volume change since it is based on cross-sectional area measurements.

  12. Segmentation of urinary bladder in CT urography (CTU) using CLASS with enhanced contour conjoint procedure

    NASA Astrophysics Data System (ADS)

    Cha, Kenny; Hadjiiski, Lubomir; Chan, Heang-Ping; Cohan, Richard H.; Caoili, Elaine M.; Zhou, Chuan

    2014-03-01

    We are developing a computerized method for bladder segmentation in CT urography (CTU) for computeraided diagnosis of bladder cancer. A challenge for computerized bladder segmentation in CTU is that the bladder often contains regions filled with intravenous (IV) contrast and without contrast. Previously, we proposed a Conjoint Level set Analysis and Segmentation System (CLASS) consisting of four stages: preprocessing and initial segmentation, 3D and 2D level set segmentation, and post-processing. In case the bladder is partially filled with contrast, CLASS segments the non-contrast (NC) region and the contrast (C) filled region separately and conjoins the contours with a Contour Conjoint Procedure (CCP). The CCP is not trivial. Inaccuracies in the NC and C contours may cause CCP to exclude portions of the bladder. To alleviate this problem, we implemented model-guided refinement to propagate the C contour if the level set propagation in the region stops prematurely due to substantial non-uniformity of the contrast. An enhanced CCP with regularized energies further propagates the conjoint contours to the correct bladder boundary. Segmentation performance was evaluated using 70 cases. For all cases, 3D hand segmented contours were obtained as reference standard, and computerized segmentation accuracy was evaluated in terms of average volume intersection %, average % volume error, and average minimum distance. With enhanced CCP, those values were 84.4±10.6%, 8.3±16.1%, 3.4±1.8 mm, respectively. With CLASS, those values were 74.6±13.1%, 19.6±18.6%, 4.4±2.2 mm, respectively. The enhanced CCP improved bladder segmentation significantly (p<0.001) for all three performance measures.

  13. Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

    SciTech Connect

    Juneja, Prabhjot; Harris, Emma J.; Kirby, Anna M.; Evans, Philip M.

    2012-11-01

    Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation

  14. Automated bone segmentation from dental CBCT images using patch-based sparse representation and convex optimization

    PubMed Central

    Wang, Li; Chen, Ken Chung; Gao, Yaozong; Shi, Feng; Liao, Shu; Li, Gang; Shen, Steve G. F.; Yan, Jin; Lee, Philip K. M.; Chow, Ben; Liu, Nancy X.; Xia, James J.; Shen, Dinggang

    2014-01-01

    Purpose: Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the poor image quality, including very low signal-to-noise ratio and the widespread image artifacts such as noise, beam hardening, and inhomogeneity, it is challenging to segment the CBCT images. In this paper, the authors present a new automatic segmentation method to address these problems. Methods: To segment CBCT images, the authors propose a new method for fully automated CBCT segmentation by using patch-based sparse representation to (1) segment bony structures from the soft tissues and (2) further separate the mandible from the maxilla. Specifically, a region-specific registration strategy is first proposed to warp all the atlases to the current testing subject and then a sparse-based label propagation strategy is employed to estimate a patient-specific atlas from all aligned atlases. Finally, the patient-specific atlas is integrated into a maximum a posteriori probability-based convex segmentation framework for accurate segmentation. Results: The proposed method has been evaluated on a dataset with 15 CBCT images. The effectiveness of the proposed region-specific registration strategy and patient-specific atlas has been validated by comparing with the traditional registration strategy and population-based atlas. The experimental results show that the proposed method achieves the best segmentation accuracy by comparison with other state-of-the-art segmentation methods. Conclusions: The authors have proposed a new CBCT segmentation method by using patch-based sparse representation and convex optimization, which can achieve considerably accurate segmentation results in CBCT

  15. Automated bone segmentation from dental CBCT images using patch-based sparse representation and convex optimization

    SciTech Connect

    Wang, Li; Gao, Yaozong; Shi, Feng; Liao, Shu; Li, Gang; Chen, Ken Chung; Shen, Steve G. F.; Yan, Jin; Lee, Philip K. M.; Chow, Ben; Liu, Nancy X.; Xia, James J.; Shen, Dinggang

    2014-04-15

    Purpose: Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the poor image quality, including very low signal-to-noise ratio and the widespread image artifacts such as noise, beam hardening, and inhomogeneity, it is challenging to segment the CBCT images. In this paper, the authors present a new automatic segmentation method to address these problems. Methods: To segment CBCT images, the authors propose a new method for fully automated CBCT segmentation by using patch-based sparse representation to (1) segment bony structures from the soft tissues and (2) further separate the mandible from the maxilla. Specifically, a region-specific registration strategy is first proposed to warp all the atlases to the current testing subject and then a sparse-based label propagation strategy is employed to estimate a patient-specific atlas from all aligned atlases. Finally, the patient-specific atlas is integrated into amaximum a posteriori probability-based convex segmentation framework for accurate segmentation. Results: The proposed method has been evaluated on a dataset with 15 CBCT images. The effectiveness of the proposed region-specific registration strategy and patient-specific atlas has been validated by comparing with the traditional registration strategy and population-based atlas. The experimental results show that the proposed method achieves the best segmentation accuracy by comparison with other state-of-the-art segmentation methods. Conclusions: The authors have proposed a new CBCT segmentation method by using patch-based sparse representation and convex optimization, which can achieve considerably accurate segmentation results in CBCT

  16. Multiscale 3-D Shape Representation and Segmentation Using Spherical Wavelets

    PubMed Central

    Nain, Delphine; Haker, Steven; Bobick, Aaron

    2013-01-01

    This paper presents a novel multiscale shape representation and segmentation algorithm based on the spherical wavelet transform. This work is motivated by the need to compactly and accurately encode variations at multiple scales in the shape representation in order to drive the segmentation and shape analysis of deep brain structures, such as the caudate nucleus or the hippocampus. Our proposed shape representation can be optimized to compactly encode shape variations in a population at the needed scale and spatial locations, enabling the construction of more descriptive, nonglobal, nonuniform shape probability priors to be included in the segmentation and shape analysis framework. In particular, this representation addresses the shortcomings of techniques that learn a global shape prior at a single scale of analysis and cannot represent fine, local variations in a population of shapes in the presence of a limited dataset. Specifically, our technique defines a multiscale parametric model of surfaces belonging to the same population using a compact set of spherical wavelets targeted to that population. We further refine the shape representation by separating into groups wavelet coefficients that describe independent global and/or local biological variations in the population, using spectral graph partitioning. We then learn a prior probability distribution induced over each group to explicitly encode these variations at different scales and spatial locations. Based on this representation, we derive a parametric active surface evolution using the multiscale prior coefficients as parameters for our optimization procedure to naturally include the prior for segmentation. Additionally, the optimization method can be applied in a coarse-to-fine manner. We apply our algorithm to two different brain structures, the caudate nucleus and the hippocampus, of interest in the study of schizophrenia. We show: 1) a reconstruction task of a test set to validate the expressiveness of

  17. Multiscale 3-D shape representation and segmentation using spherical wavelets.

    PubMed

    Nain, Delphine; Haker, Steven; Bobick, Aaron; Tannenbaum, Allen

    2007-04-01

    This paper presents a novel multiscale shape representation and segmentation algorithm based on the spherical wavelet transform. This work is motivated by the need to compactly and accurately encode variations at multiple scales in the shape representation in order to drive the segmentation and shape analysis of deep brain structures, such as the caudate nucleus or the hippocampus. Our proposed shape representation can be optimized to compactly encode shape variations in a population at the needed scale and spatial locations, enabling the construction of more descriptive, nonglobal, nonuniform shape probability priors to be included in the segmentation and shape analysis framework. In particular, this representation addresses the shortcomings of techniques that learn a global shape prior at a single scale of analysis and cannot represent fine, local variations in a population of shapes in the presence of a limited dataset. Specifically, our technique defines a multiscale parametric model of surfaces belonging to the same population using a compact set of spherical wavelets targeted to that population. We further refine the shape representation by separating into groups wavelet coefficients that describe independent global and/or local biological variations in the population, using spectral graph partitioning. We then learn a prior probability distribution induced over each group to explicitly encode these variations at different scales and spatial locations. Based on this representation, we derive a parametric active surface evolution using the multiscale prior coefficients as parameters for our optimization procedure to naturally include the prior for segmentation. Additionally, the optimization method can be applied in a coarse-to-fine manner. We apply our algorithm to two different brain structures, the caudate nucleus and the hippocampus, of interest in the study of schizophrenia. We show: 1) a reconstruction task of a test set to validate the expressiveness of

  18. Automated segmentation of serous pigment epithelium detachment in SD-OCT images

    NASA Astrophysics Data System (ADS)

    Sun, Zhuli; Shi, Fei; Xiang, Dehui; Chen, Haoyu; Chen, Xinjian

    2015-03-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorio-retinal disease processes, which can cause the loss of central vision. A 3-D method is proposed to automatically segment serous PED in SD-OCT images. The proposed method consists of five steps: first, a curvature anisotropic diffusion filter is applied to remove speckle noise. Second, the graph search method is applied for abnormal retinal layer segmentation associated with retinal pigment epithelium (RPE) deformation. During this process, Bruch's membrane, which doesn't show in the SD-OCT images, is estimated with the convex hull algorithm. Third, the foreground and background seeds are automatically obtained from retinal layer segmentation result. Fourth, the serous PED is segmented based on the graph cut method. Finally, a post-processing step is applied to remove false positive regions based on mathematical morphology. The proposed method was tested on 20 SD-OCT volumes from 20 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 97.19%, 0.03%, 96.34% and 95.59%, respectively. Linear regression analysis shows a strong correlation (r = 0.975) comparing the segmented PED volumes with the ground truth labeled by an ophthalmology expert. The proposed method can provide clinicians with accurate quantitative information, including shape, size and position of the PED regions, which can assist diagnose and treatment.

  19. NOTE Thyroid volume measurement in external beam radiotherapy patients using CT imaging: correlation with clinical and anthropometric characteristics

    NASA Astrophysics Data System (ADS)

    Veres, C.; Garsi, J. P.; Rubino, C.; Pouzoulet, F.; Bidault, F.; Chavaudra, J.; Bridier, A.; Ricard, M.; Ferreira, I.; Lefkopoulos, D.; de Vathaire, F.; Diallo, I.

    2010-11-01

    The aim of this study is to define criteria for accurate representation of the thyroid in human models used to represent external beam radiotherapy (EBRT) patients and evaluate the relationship between the volume of this organ and clinical and anthropometric characteristics. From CT images, we segmented the thyroid gland and calculated its volume for a population of 188 EBRT patients of both sexes, with ages ranging from 1 to 89 years. To evaluate uncertainties linked to measured volumes, experimental studies on the Livermore anthropomorphic phantom were performed. For our population of EBRT patients, we observed that in children, thyroid volume increased rapidly with age, from about 3 cm3 at 2 years to about 16 cm3 at 20. In adults, the mean thyroid gland volume was 23.5 ± 9 cm3 for males and 17.5 ± 8 cm3 for females. According to anthropometric parameters, the best fit for children was obtained by modeling the log of thyroid volume as a linear function of body surface area (BSA) (p < 0.0001) and age (p = 0.04) and for adults, as a linear function of BSA (p < 0.0001) and gender (p = 0.01). This work enabled us to demonstrate that BSA was the best indicator of thyroid volume for both males and females. These results should be taken into account when modeling the volume of the thyroid in human models used to represent EBRT patients for dosimetry in retrospective studies of the relationship between the estimated dose to the thyroid and long-term follow-up data on EBRT patients.

  20. Measuring the success of video segmentation algorithms

    NASA Astrophysics Data System (ADS)

    Power, Gregory J.

    2001-12-01

    Appropriate segmentation of video is a key step for applications such as video surveillance, video composing, video compression, storage and retrieval, and automated target recognition. Video segmentation algorithms involve dissecting the video into scenes based on shot boundaries as well as local objects and events based on spatial shape and regional motions. Many algorithmic approaches to video segmentation have been recently reported, but many lack measures to quantify the success of the segmentation especially in comparison to other algorithms. This paper suggests multiple bench-top measures for evaluating video segmentation. The paper suggests that the measures are most useful when 'truth' data about the video is available such as precise frame-by- frame object shape. When precise 'truth' data is unavailable, this paper suggests using hand-segmented 'truth' data to measure the success of the video segmentation. Thereby, the ability of the video segmentation algorithm to achieve the same quality of segmentation as the human is obtained in the form of a variance in multiple measures. The paper introduces a suite of measures, each scaled from zero to one. A score of one on a particular measure is a perfect score for a singular segmentation measure. Measures are introduced to evaluate the ability of a segmentation algorithm to correctly detect shot boundaries, to correctly determine spatial shape and to correctly determine temporal shape. The usefulness of the measures are demonstrated on a simple segmenter designed to detect and segment a ping pong ball from a table tennis image sequence.

  1. Inertial properties of equine limb segments.

    PubMed

    Nauwelaerts, Sandra; Allen, Whitney A; Lane, Jasmine M; Clayton, Hilary M

    2011-05-01

    Quantifying the dynamics of limb movements requires knowledge of the mass distribution between and within limb segments. We measured segment masses, positions of segmental center of mass and moments of inertia of the fore and hind limb segments for 38 horses of different breeds and sizes. After disarticulation by dissections, segments were weighed and the position of the center of mass was determined by suspension. Moment of inertia was measured using a trifilar pendulum. We found that mass distribution does not change with size for animals under 600 kg and report ratios of segmental masses to total body mass. For all segments, the scaling relationship between segmental mass and moment of inertia was predicted equally well or better by a 5/3 power fit than by the more classic mass multiplied by segmental length squared fit. Average values taken from previous studies generally confirmed our data but scaling relationships often needed to be revised. We did not detect an effect of morphotype on segment inertial properties. Differences in segmental inertial properties between published studies may depend more on segmental segmentation techniques than on size or body type of the horse. PMID:21355866

  2. Comparison of human and automatic segmentations of kidneys from CT images

    SciTech Connect

    Rao, Manjori; Stough, Joshua; Chi, Y.-Y.; Muller, Keith; Tracton, Gregg; Pizer, Stephen M.; Chaney, Edward L. . E-mail: chaney@med.unc.edu

    2005-03-01

    Purpose: A controlled observer study was conducted to compare a method for automatic image segmentation with conventional user-guided segmentation of right and left kidneys from planning computerized tomographic (CT) images. Methods and materials: Deformable shape models called m-reps were used to automatically segment right and left kidneys from 12 target CT images, and the results were compared with careful manual segmentations performed by two human experts. M-rep models were trained based on manual segmentations from a collection of images that did not include the targets. Segmentation using m-reps began with interactive initialization to position the kidney model over the target kidney in the image data. Fully automatic segmentation proceeded through two stages at successively smaller spatial scales. At the first stage, a global similarity transformation of the kidney model was computed to position the model closer to the target kidney. The similarity transformation was followed by large-scale deformations based on principal geodesic analysis (PGA). During the second stage, the medial atoms comprising the m-rep model were deformed one by one. This procedure was iterated until no changes were observed. The transformations and deformations at both stages were driven by optimizing an objective function with two terms. One term penalized the currently deformed m-rep by an amount proportional to its deviation from the mean m-rep derived from PGA of the training segmentations. The second term computed a model-to-image match term based on the goodness of match of the trained intensity template for the currently deformed m-rep with the corresponding intensity data in the target image. Human and m-rep segmentations were compared using quantitative metrics provided in a toolset called Valmet. Metrics reported in this article include (1) percent volume overlap; (2) mean surface distance between two segmentations; and (3) maximum surface separation (Hausdorff distance

  3. Unsupervised segmentation of MRI knees using image partition forests

    NASA Astrophysics Data System (ADS)

    Marčan, Marija; Voiculescu, Irina

    2016-03-01

    Nowadays many people are affected by arthritis, a condition of the joints with limited prevention measures, but with various options of treatment the most radical of which is surgical. In order for surgery to be successful, it can make use of careful analysis of patient-based models generated from medical images, usually by manual segmentation. In this work we show how to automate the segmentation of a crucial and complex joint -- the knee. To achieve this goal we rely on our novel way of representing a 3D voxel volume as a hierarchical structure of partitions which we have named Image Partition Forest (IPF). The IPF contains several partition layers of increasing coarseness, with partitions nested across layers in the form of adjacency graphs. On the basis of a set of properties (size, mean intensity, coordinates) of each node in the IPF we classify nodes into different features. Values indicating whether or not any particular node belongs to the femur or tibia are assigned through node filtering and node-based region growing. So far we have evaluated our method on 15 MRI knee images. Our unsupervised segmentation compared against a hand-segmented gold standard has achieved an average Dice similarity coefficient of 0.95 for femur and 0.93 for tibia, and an average symmetric surface distance of 0.98 mm for femur and 0.73 mm for tibia. The paper also discusses ways to introduce stricter morphological and spatial conditioning in the bone labelling process.

  4. NABS: non-local automatic brain hemisphere segmentation.

    PubMed

    Romero, José E; Manjón, José V; Tohka, Jussi; Coupé, Pierrick; Robles, Montserrat

    2015-05-01

    In this paper, we propose an automatic method to segment the five main brain sub-regions (i.e. left/right hemispheres, left/right cerebellum and brainstem) from magnetic resonance images. The proposed method uses a library of pre-labeled brain images in a stereotactic space in combination with a non-local label fusion scheme for segmentation. The main novelty of the proposed method is the use of a multi-label block-wise label fusion strategy specifically designed to deal with the classification of main brain sub-volumes that process only specific parts of the brain images significantly reducing the computational burden. The proposed method has been quantitatively evaluated against manual segmentations. The evaluation showed that the proposed method was faster while producing more accurate segmentations than a current state-of-the-art method. We also present evidences suggesting that the proposed method was more robust against brain pathologies than the compared method. Finally, we demonstrate the clinical value of our method compared to the state-of-the-art approach in terms of the asymmetry quantification in Alzheimer's disease. PMID:25660644

  5. Factorization-based texture segmentation

    DOE PAGES

    Yuan, Jiangye; Wang, Deliang; Cheriyadat, Anil M.

    2015-06-17

    This study introduces a factorization-based approach that efficiently segments textured images. We use local spectral histograms as features, and construct an M × N feature matrix using M-dimensional feature vectors in an N-pixel image. Based on the observation that each feature can be approximated by a linear combination of several representative features, we factor the feature matrix into two matrices-one consisting of the representative features and the other containing the weights of representative features at each pixel used for linear combination. The factorization method is based on singular value decomposition and nonnegative matrix factorization. The method uses local spectral histogramsmore » to discriminate region appearances in a computationally efficient way and at the same time accurately localizes region boundaries. Finally, the experiments conducted on public segmentation data sets show the promise of this simple yet powerful approach.« less

  6. Printed Arabic optical character segmentation

    NASA Astrophysics Data System (ADS)

    Mohammad, Khader; Ayyesh, Muna; Qaroush, Aziz; Tumar, Iyad

    2015-03-01

    A considerable progress in recognition techniques for many non-Arabic characters has been achieved. In contrary, few efforts have been put on the research of Arabic characters. In any Optical Character Recognition (OCR) system the segmentation step is usually the essential stage in which an extensive portion of processing is devoted and a considerable share of recognition errors is attributed. In this research, a novel segmentation approach for machine Arabic printed text with diacritics is proposed. The proposed method reduces computation, errors, gives a clear description for the sub-word and has advantages over using the skeleton approach in which the data and information of the character can be lost. Both of initial evaluation and testing of the proposed method have been developed using MATLAB and shows 98.7% promising results.

  7. Random walks for image segmentation.

    PubMed

    Grady, Leo

    2006-11-01

    A novel method is proposed for performing multilabel, interactive image segmentation. Given a small number of pixels with user-defined (or predefined) labels, one can analytically and quickly determine the probability that a random walker starting at each unlabeled pixel will first reach one of the prelabeled pixels. By assigning each pixel to the label for which the greatest probability is calculated, a high-quality image segmentation may be obtained. Theoretical properties of this algorithm are developed along with the corresponding connections to discrete potential theory and electrical circuits. This algorithm is formulated in discrete space (i.e., on a graph) using combinatorial analogues of standard operators and principles from continuous potential theory, allowing it to be applied in arbitrary dimension on arbitrary graphs.

  8. Factorization-based texture segmentation

    SciTech Connect

    Yuan, Jiangye; Wang, Deliang; Cheriyadat, Anil M.

    2015-06-17

    This study introduces a factorization-based approach that efficiently segments textured images. We use local spectral histograms as features, and construct an M × N feature matrix using M-dimensional feature vectors in an N-pixel image. Based on the observation that each feature can be approximated by a linear combination of several representative features, we factor the feature matrix into two matrices-one consisting of the representative features and the other containing the weights of representative features at each pixel used for linear combination. The factorization method is based on singular value decomposition and nonnegative matrix factorization. The method uses local spectral histograms to discriminate region appearances in a computationally efficient way and at the same time accurately localizes region boundaries. Finally, the experiments conducted on public segmentation data sets show the promise of this simple yet powerful approach.

  9. Polyp Segmentation in NBI Colonoscopy

    NASA Astrophysics Data System (ADS)

    Gross, Sebastian; Kennel, Manuel; Stehle, Thomas; Wulff, Jonas; Tischendorf, Jens; Trautwein, Christian; Aach, Til

    Endoscopic screening of the colon (colonoscopy) is performed to prevent cancer and to support therapy. During intervention colon polyps are located, inspected and, if need be, removed by the investigator. We propose a segmentation algorithm as a part of an automatic polyp classification system for colonoscopic Narrow-Band images. Our approach includes multi-scale filtering for noise reduction, suppression of small blood vessels, and enhancement of major edges. Results of the subsequent edge detection are compared to a set of elliptic templates and evaluated. We validated our algorithm on our polyp database with images acquired during routine colonoscopic examinations. The presented results show the reliable segmentation performance of our method and its robustness to image variations.

  10. Segment aberration effects on contrast.

    PubMed

    Crossfield, Ian J; Troy, Mitchell

    2007-07-20

    High-contrast imaging, particularly the direct detection of extrasolar planets, is a major science driver for the next generation of telescopes. This science requires the suppression of scattered starlight at extremely high levels and that telescopes be correctly designed today to meet these stringent requirements in the future. The challenge increases in systems with complicated aperture geometries such as obscured, segmented telescopes. Such systems can also require intensive modeling and simulation efforts in order to understand the trade-offs between different optical parameters. The feasibility and development of a contrast prediction tool for use in the design and systems engineering of these telescopes is described. The performance of a particular starlight suppression system on a large segmented telescope is described analytically. These analytical results and the results of a contrast predictor are then compared with the results of a full wave-optics simulation. PMID:17609697

  11. Rigid shape matching by segmentation averaging.

    PubMed

    Wang, Hongzhi; Oliensis, John

    2010-04-01

    We use segmentations to match images by shape. The new matching technique does not require point-to-point edge correspondence and is robust to small shape variations and spatial shifts. To address the unreliability of segmentations computed bottom-up, we give a closed form approximation to an average over all segmentations. Our method has many extensions, yielding new algorithms for tracking, object detection, segmentation, and edge-preserving smoothing. For segmentation, instead of a maximum a posteriori approach, we compute the "central" segmentation minimizing the average distance to all segmentations of an image. For smoothing, instead of smoothing images based on local structures, we smooth based on the global optimal image structures. Our methods for segmentation, smoothing, and object detection perform competitively, and we also show promising results in shape-based tracking.

  12. Segmented Coil Fails In Steps

    NASA Technical Reports Server (NTRS)

    Stedman, Ronald S.

    1990-01-01

    Electromagnetic coil degrades in steps when faults occur, continues to operate at reduced level instead of failing catastrophically. Made in segments connected in series and separated by electrically insulating barriers. Fault does not damage adjacent components or create hazard. Used to control valves in such critical applications as cooling systems of power generators and chemical process equipment, where flammable liquids or gases handled. Also adapts to electrical control of motors.

  13. Adaptive image segmentation by quantization

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Yun, David Y.

    1992-12-01

    Segmentation of images into textural homogeneous regions is a fundamental problem in an image understanding system. Most region-oriented segmentation approaches suffer from the problem of different thresholds selecting for different images. In this paper an adaptive image segmentation based on vector quantization is presented. It automatically segments images without preset thresholds. The approach contains a feature extraction module and a two-layer hierarchical clustering module, a vector quantizer (VQ) implemented by a competitive learning neural network in the first layer. A near-optimal competitive learning algorithm (NOLA) is employed to train the vector quantizer. NOLA combines the advantages of both Kohonen self- organizing feature map (KSFM) and K-means clustering algorithm. After the VQ is trained, the weights of the network and the number of input vectors clustered by each neuron form a 3- D topological feature map with separable hills aggregated by similar vectors. This overcomes the inability to visualize the geometric properties of data in a high-dimensional space for most other clustering algorithms. The second clustering algorithm operates in the feature map instead of the input set itself. Since the number of units in the feature map is much less than the number of feature vectors in the feature set, it is easy to check all peaks and find the `correct' number of clusters, also a key problem in current clustering techniques. In the experiments, we compare our algorithm with K-means clustering method on a variety of images. The results show that our algorithm achieves better performance.

  14. Color segmentation using MDL clustering

    NASA Astrophysics Data System (ADS)

    Wallace, Richard S.; Suenaga, Yasuhito

    1991-02-01

    This paper describes a procedure for segmentation of color face images. A cluster analysis algorithm uses a subsample of the input image color pixels to detect clusters in color space. The clustering program consists of two parts. The first part searches for a hierarchical clustering using the NIHC algorithm. The second part searches the resultant cluster tree for a level clustering having minimum description length (MDL). One of the primary advantages of the MDL paradigm is that it enables writing robust vision algorithms that do not depend on user-specified threshold parameters or other " magic numbers. " This technical note describes an application of minimal length encoding in the analysis of digitized human face images at the NTT Human Interface Laboratories. We use MDL clustering to segment color images of human faces. For color segmentation we search for clusters in color space. Using only a subsample of points from the original face image our clustering program detects color clusters corresponding to the hair skin and background regions in the image. Then a maximum likelyhood classifier assigns the remaining pixels to each class. The clustering program tends to group small facial features such as the nostrils mouth and eyes together but they can be separated from the larger classes through connected components analysis.

  15. Segmentation in local hospital markets.

    PubMed

    Dranove, D; White, W D; Wu, L

    1993-01-01

    This study examines evidence of market segmentation on the basis of patients' insurance status, demographic characteristics, and medical condition in selected local markets in California in the years 1983 and 1989. Substantial differences exist in the probability patients may be admitted to particular hospitals based on insurance coverage, particularly Medicaid, and race. Segmentation based on insurance and race is related to hospital characteristics, but not the characteristics of the hospital's community. Medicaid patients are more likely to go to hospitals with lower costs and fewer service offerings. Privately insured patients go to hospitals offering more services, although cost concerns are increasing. Hispanic patients also go to low-cost hospitals, ceteris paribus. Results indicate little evidence of segmentation based on medical condition in either 1983 or 1989, suggesting that "centers of excellence" have yet to play an important role in patient choice of hospital. The authors found that distance matters, and that patients prefer nearby hospitals, moreso for some medical conditions than others, in ways consistent with economic theories of consumer choice.

  16. Primary mirror segment fabrication for CELT

    NASA Astrophysics Data System (ADS)

    Mast, Terry S.; Nelson, Jerry E.; Sommargren, Gary E.

    2000-07-01

    The primary mirror of the proposed California Extremely Large Telescope is a 30-meter diameter mosaic of hexagonal segments. An initial design calls for about a thousand segments with a hexagon side length of 0.5 meters, a primary-mirror focal ratio of 1.5, and a segment surface quality of about 20 nanometers rms. We describe concepts for fabricating these segments.

  17. Segmenting the mental health care market.

    PubMed

    Stone, T R; Warren, W E; Stevens, R E

    1990-03-01

    The authors report the results of a segmentation study of the mental health care market. A random sample of 387 residents of a western city were interviewed by telephone. Cluster analysis of the data identified six market segments. Each is described according to the mental health care services to which it is most sensitive. Implications for targeting the segments are discussed.

  18. Quick Dissection of the Segmental Bronchi

    ERIC Educational Resources Information Center

    Nakajima, Yuji

    2010-01-01

    Knowledge of the three-dimensional anatomy of the bronchopulmonary segments is essential for respiratory medicine. This report describes a quick guide for dissecting the segmental bronchi in formaldehyde-fixed human material. All segmental bronchi are easy to dissect, and thus, this exercise will help medical students to better understand the…

  19. Market Segmentation from a Behavioral Perspective

    ERIC Educational Resources Information Center

    Wells, Victoria K.; Chang, Shing Wan; Oliveira-Castro, Jorge; Pallister, John

    2010-01-01

    A segmentation approach is presented using both traditional demographic segmentation bases (age, social class/occupation, and working status) and a segmentation by benefits sought. The benefits sought in this case are utilitarian and informational reinforcement, variables developed from the Behavioral Perspective Model (BPM). Using data from 1,847…

  20. Segmental Refinement: A Multigrid Technique for Data Locality

    SciTech Connect

    Adams, Mark

    2014-10-27

    We investigate a technique - segmental refinement (SR) - proposed by Brandt in the 1970s as a low memory multigrid method. The technique is attractive for modern computer architectures because it provides high data locality, minimizes network communication, is amenable to loop fusion, and is naturally highly parallel and asynchronous. The network communication minimization property was recognized by Brandt and Diskin in 1994; we continue this work by developing a segmental refinement method for a finite volume discretization of the 3D Laplacian on massively parallel computers. An understanding of the asymptotic complexities, required to maintain textbook multigrid efficiency, are explored experimentally with a simple SR method. A two-level memory model is developed to compare the asymptotic communication complexity of a proposed SR method with traditional parallel multigrid. Performance and scalability are evaluated with a Cray XC30 with up to 64K cores. We achieve modest improvement in scalability from traditional parallel multigrid with a simple SR implementation.

  1. Confidence-based ensemble for GBM brain tumor segmentation

    NASA Astrophysics Data System (ADS)

    Huo, Jing; van Rikxoort, Eva M.; Okada, Kazunori; Kim, Hyun J.; Pope, Whitney; Goldin, Jonathan; Brown, Matthew

    2011-03-01

    It is a challenging task to automatically segment glioblastoma multiforme (GBM) brain tumors on T1w post-contrast isotropic MR images. A semi-automated system using fuzzy connectedness has recently been developed for computing the tumor volume that reduces the cost of manual annotation. In this study, we propose a an ensemble method that combines multiple segmentation results into a final ensemble one. The method is evaluated on a dataset of 20 cases from a multi-center pharmaceutical drug trial and compared to the fuzzy connectedness method. Three individual methods were used in the framework: fuzzy connectedness, GrowCut, and voxel classification. The combination method is a confidence map averaging (CMA) method. The CMA method shows an improved ROC curve compared to the fuzzy connectedness method (p < 0.001). The CMA ensemble result is more robust compared to the three individual methods.

  2. Automated brain tumor segmentation using spatial accuracy-weighted hidden Markov Random Field.

    PubMed

    Nie, Jingxin; Xue, Zhong; Liu, Tianming; Young, Geoffrey S; Setayesh, Kian; Guo, Lei; Wong, Stephen T C

    2009-09-01

    A variety of algorithms have been proposed for brain tumor segmentation from multi-channel sequences, however, most of them require isotropic or pseudo-isotropic resolution of the MR images. Although co-registration and interpolation of low-resolution sequences, such as T2-weighted images, onto the space of the high-resolution image, such as T1-weighted image, can be performed prior to the segmentation, the results are usually limited by partial volume effects due to interpolation of low-resolution images. To improve the quality of tumor segmentation in clinical applications where low-resolution sequences are commonly used together with high-resolution images, we propose the algorithm based on Spatial accuracy-weighted Hidden Markov random field and Expectation maximization (SHE) approach for both automated tumor and enhanced-tumor segmentation. SHE incorporates the spatial interpolation accuracy of low-resolution images into the optimization procedure of the Hidden Markov Random Field (HMRF) to segment tumor using multi-channel MR images with different resolutions, e.g., high-resolution T1-weighted and low-resolution T2-weighted images. In experiments, we evaluated this algorithm using a set of simulated multi-channel brain MR images with known ground-truth tissue segmentation and also applied it to a dataset of MR images obtained during clinical trials of brain tumor chemotherapy. The results show that more accurate tumor segmentation results can be obtained by comparing with conventional multi-channel segmentation algorithms.

  3. Interactive and scale invariant segmentation of the rectum/sigmoid via user-defined templates

    NASA Astrophysics Data System (ADS)

    Lüddemann, Tobias; Egger, Jan

    2016-03-01

    Among all types of cancer, gynecological malignancies belong to the 4th most frequent type of cancer among women. Besides chemotherapy and external beam radiation, brachytherapy is the standard procedure for the treatment of these malignancies. In the progress of treatment planning, localization of the tumor as the target volume and adjacent organs of risks by segmentation is crucial to accomplish an optimal radiation distribution to the tumor while simultaneously preserving healthy tissue. Segmentation is performed manually and represents a time-consuming task in clinical daily routine. This study focuses on the segmentation of the rectum/sigmoid colon as an Organ-At-Risk in gynecological brachytherapy. The proposed segmentation method uses an interactive, graph-based segmentation scheme with a user-defined template. The scheme creates a directed two dimensional graph, followed by the minimal cost closed set computation on the graph, resulting in an outlining of the rectum. The graphs outline is dynamically adapted to the last calculated cut. Evaluation was performed by comparing manual segmentations of the rectum/sigmoid colon to results achieved with the proposed method. The comparison of the algorithmic to manual results yielded to a Dice Similarity Coefficient value of 83.85+/-4.08%, in comparison to 83.97+/-8.08% for the comparison of two manual segmentations of the same physician. Utilizing the proposed methodology resulted in a median time of 128 seconds per dataset, compared to 300 seconds needed for pure manual segmentation.

  4. Automated brain tumor segmentation using spatial accuracy-weighted hidden Markov Random Field.

    PubMed

    Nie, Jingxin; Xue, Zhong; Liu, Tianming; Young, Geoffrey S; Setayesh, Kian; Guo, Lei; Wong, Stephen T C

    2009-09-01

    A variety of algorithms have been proposed for brain tumor segmentation from multi-channel sequences, however, most of them require isotropic or pseudo-isotropic resolution of the MR images. Although co-registration and interpolation of low-resolution sequences, such as T2-weighted images, onto the space of the high-resolution image, such as T1-weighted image, can be performed prior to the segmentation, the results are usually limited by partial volume effects due to interpolation of low-resolution images. To improve the quality of tumor segmentation in clinical applications where low-resolution sequences are commonly used together with high-resolution images, we propose the algorithm based on Spatial accuracy-weighted Hidden Markov random field and Expectation maximization (SHE) approach for both automated tumor and enhanced-tumor segmentation. SHE incorporates the spatial interpolation accuracy of low-resolution images into the optimization procedure of the Hidden Markov Random Field (HMRF) to segment tumor using multi-channel MR images with different resolutions, e.g., high-resolution T1-weighted and low-resolution T2-weighted images. In experiments, we evaluated this algorithm using a set of simulated multi-channel brain MR images with known ground-truth tissue segmentation and also applied it to a dataset of MR images obtained during clinical trials of brain tumor chemotherapy. The results show that more accurate tumor segmentation results can be obtained by comparing with conventional multi-channel segmentation algorithms. PMID:19446435

  5. Viral Genome Segmentation Can Result from a Trade-Off between Genetic Content and Particle Stability

    PubMed Central

    Ojosnegros, Samuel; García-Arriaza, Juan; Escarmís, Cristina; Manrubia, Susanna C.; Perales, Celia; Arias, Armando; Mateu, Mauricio García; Domingo, Esteban

    2011-01-01

    The evolutionary benefit of viral genome segmentation is a classical, yet unsolved question in evolutionary biology and RNA genetics. Theoretical studies anticipated that replication of shorter RNA segments could provide a replicative advantage over standard size genomes. However, this question has remained elusive to experimentalists because of the lack of a proper viral model system. Here we present a study with a stable segmented bipartite RNA virus and its ancestor non-segmented counterpart, in an identical genomic nucleotide sequence context. Results of RNA replication, protein expression, competition experiments, and inactivation of infectious particles point to a non-replicative trait, the particle stability, as the main driver of fitness gain of segmented genomes. Accordingly, measurements of the volume occupation of the genome inside viral capsids indicate that packaging shorter genomes involves a relaxation of the packaging density that is energetically favourable. The empirical observations are used to design a computational model that predicts the existence of a critical multiplicity of infection for domination of segmented over standard types. Our experiments suggest that viral segmented genomes may have arisen as a molecular solution for the trade-off between genome length and particle stability. Genome segmentation allows maximizing the genetic content without the detrimental effect in stability derived from incresing genome length. PMID:21437265

  6. Fully Automated Segmentation of the Pons and Midbrain Using Human T1 MR Brain Images

    PubMed Central

    Nigro, Salvatore; Cerasa, Antonio; Zito, Giancarlo; Perrotta, Paolo; Chiaravalloti, Francesco; Donzuso, Giulia; Fera, Franceso; Bilotta, Eleonora; Pantano, Pietro; Quattrone, Aldo

    2014-01-01

    Purpose This paper describes a novel method to automatically segment the human brainstem into midbrain and pons, called LABS: Landmark-based Automated Brainstem Segmentation. LABS processes high-resolution structural magnetic resonance images (MRIs) according to a revised landmark-based approach integrated with a thresholding method, without manual interaction. Methods This method was first tested on morphological T1-weighted MRIs of 30 healthy subjects. Its reliability was further confirmed by including neurological patients (with Alzheimer's Disease) from the ADNI repository, in whom the presence of volumetric loss within the brainstem had been previously described. Segmentation accuracies were evaluated against expert-drawn manual delineation. To evaluate the quality of LABS segmentation we used volumetric, spatial overlap and distance-based metrics. Results The comparison between the quantitative measurements provided by LABS against manual segmentations revealed excellent results in healthy controls when considering either the midbrain (DICE measures higher that 0.9; Volume ratio around 1 and Hausdorff distance around 3) or the pons (DICE measures around 0.93; Volume ratio ranging 1.024–1.05 and Hausdorff distance around 2). Similar performances were detected for AD patients considering segmentation of the pons (DICE measures higher that 0.93; Volume ratio ranging from 0.97–0.98 and Hausdorff distance ranging 1.07–1.33), while LABS performed lower for the midbrain (DICE measures ranging 0.86–0.88; Volume ratio around 0.95 and Hausdorff distance ranging 1.71–2.15). Conclusions Our study represents the first attempt to validate a new fully automated method for in vivo segmentation of two anatomically complex brainstem subregions. We retain that our method might represent a useful tool for future applications in clinical practice. PMID:24489664

  7. Automatic segmentation and volumetry of multiple sclerosis brain lesions from MR images.

    PubMed

    Jain, Saurabh; Sima, Diana M; Ribbens, Annemie; Cambron, Melissa; Maertens, Anke; Van Hecke, Wim; De Mey, Johan; Barkhof, Frederik; Steenwijk, Martijn D; Daams, Marita; Maes, Frederik; Van Huffel, Sabine; Vrenken, Hugo; Smeets, Dirk

    2015-01-01

    The location and extent of white matter lesions on magnetic resonance imaging (MRI) are important criteria for diagnosis, follow-up and prognosis of multiple sclerosis (MS). Clinical trials have shown that quantitative values, such as lesion volumes, are meaningful in MS prognosis. Manual lesion delineation for the segmentation of lesions is, however, time-consuming and suffers from observer variability. In this paper, we propose MSmetrix, an accurate and reliable automatic method for lesion segmentation based on MRI, independent of scanner or acquisition protocol and without requiring any training data. In MSmetrix, 3D T1-weighted and FLAIR MR images are used in a probabilistic model to detect white matter (WM) lesions as an outlier to normal brain while segmenting the brain tissue into grey matter, WM and cerebrospinal fluid. The actual lesion segmentation is performed based on prior knowledge about the location (within WM) and the appearance (hyperintense on FLAIR) of lesions. The accuracy of MSmetrix is evaluated by comparing its output with expert reference segmentations of 20 MRI datasets of MS patients. Spatial overlap (Dice) between the MSmetrix and the expert lesion segmentation is 0.67 ± 0.11. The intraclass correlation coefficient (ICC) equals 0.8 indicating a good volumetric agreement between the MSmetrix and expert labelling. The reproducibility of MSmetrix' lesion volumes is evaluated based on 10 MS patients, scanned twice with a short interval on three different scanners. The agreement between the first and the second scan on each scanner is evaluated through the spatial overlap and absolute lesion volume difference between them. The spatial overlap was 0.69 ± 0.14 and absolute total lesion volume difference between the two scans was 0.54 ± 0.58 ml. Finally, the accuracy and reproducibility of MSmetrix compare favourably with other publicly available MS lesion segmentation algorithms, applied on the same data using default parameter

  8. Registration-based segmentation of murine 4D cardiac micro-CT data using symmetric normalization

    PubMed Central

    Clark, Darin; Badea, Alexandra; Liu, Yilin; Johnson, G. Allan; Badea, Cristian T.

    2013-01-01

    Micro-CT can play an important role in preclinical studies of cardiovascular disease because of its high spatial and temporal resolution. Quantitative analysis of 4D cardiac images requires segmentation of the cardiac chambers at each time point, an extremely time consuming process if done manually. To improve throughput this study proposes a pipeline for registration-based segmentation and functional analysis of 4D cardiac micro-CT data in the mouse. Following optimization and validation using simulations, the pipeline was applied to in vivo cardiac micro-CT data corresponding to 10 cardiac phases acquired in C57BL/6 mice (n = 5). After edge-preserving smoothing with a novel adaptation of 4D bilateral filtration, one phase within each cardiac sequence was manually segmented. Deformable registration was used to propagate these labels to all other cardiac phases for segmentation. The volumes of each cardiac chamber were calculated and used to derive stroke volume, ejection fraction, cardiac output, and cardiac index. Dice coefficients and volume accuracies were used to compare manual segmentations of two additional phases with their corresponding propagated labels. Both measures were, on average, >0.90 for the left ventricle and >0.80 for the myocardium, the right ventricle, and the right atrium, consistent with trends in inter- and intra-segmenter variability. Segmentation of the left atrium was less reliable. On average, the functional metrics of interest were underestimated by 6.76% or more due to systematic label propagation errors around atrioventricular valves; however, execution of the pipeline was 80% faster than performing analogous manual segmentation of each phase. PMID:22971564

  9. A Scaling Law of Vascular Volume

    PubMed Central

    Huo, Yunlong; Kassab, Ghassan S.

    2009-01-01

    Abstract Vascular volume is of fundamental significance to the function of the cardiovascular system. An accurate prediction of blood volume in patients is physiologically and clinically significant. This study proposes what we believe is a novel volume scaling relation of the form: Vc=KvDs2/3Lc, where Vc and Lc are cumulative vessel volume and length, respectively, in the tree, and Ds is the diameter of the vessel segment. The scaling relation is validated in vascular trees of various organs including the heart, lung, mesentery, muscle, and eye of different species. Based on the minimum energy hypothesis and volume scaling relation, four structure-function scaling relations are predicted, including the diameter-length, volume-length, flow-diameter, and volume-diameter relations, with exponent values of 3/7, 127, 2⅓, and 3, respectively. These four relations are validated in the various vascular trees, which further confirm the volume scaling relation. This scaling relation may serve as a control reference to estimate the blood volume in various organs and species. The deviation from the scaling relation may indicate hypovolemia or hypervolemia and aid diagnosis. PMID:19167288

  10. LACIE performance predictor final operational capability program description, volume 2

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Given the swath table files, the segment set for one country and cloud cover data, the SAGE program determines how many times and under what conditions each segment is accessed by satellites. The program writes a record for each segment on a data file which contains the pertinent acquisition data. The weather data file can also be generated from a NASA supplied tape. The Segment Acquisition Selector Program (SACS) selects data from the segment reference file based upon data input manually and from a crop window file. It writes the extracted data to a data acquisition file and prints two summary reports. The POUT program reads from associated LACIE files and produces printed reports. The major types of reports that can be produced are: (1) Substrate Reference Data Reports, (2) Population Mean, Standard Deviation and Histogram Reports, (3) Histograms of Monte Carlo Statistics Reports, and (4) Frequency of Sample Segment Acquisitions Reports.

  11. Interactive lung segmentation in abnormal human and animal chest CT scans

    SciTech Connect

    Kockelkorn, Thessa T. J. P. Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

    2014-08-15

    Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

  12. Lung vessel segmentation in CT images using graph-cuts

    NASA Astrophysics Data System (ADS)

    Zhai, Zhiwei; Staring, Marius; Stoel, Berend C.

    2016-03-01

    Accurate lung vessel segmentation is an important operation for lung CT analysis. Filters that are ba