MRBrainS Challenge: Online Evaluation Framework for Brain Image Segmentation in 3T MRI Scans

Many methods have been proposed for tissue segmentation in brain MRI scans. The multitude of methods proposed complicates the choice of one method above others. We have therefore established the MRBrainS online evaluation framework for evaluating (semi) automatic algorithms that segment gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) on 3T brain MRI scans of elderly subjects (65-80 y). Participants apply their algorithms to the provided data, after which their results are evaluated and ranked. Full manual segmentations of GM, WM, and CSF are available for all scans and used as the reference standard. Five datasets are provided for training and fifteen for testing. The evaluated methods are ranked based on their overall performance to segment GM, WM, and CSF and evaluated using three evaluation metrics (Dice, H95, and AVD) and the results are published on the MRBrainS13 website. We present the results of eleven segmentation algorithms that participated in the MRBrainS13 challenge workshop at MICCAI, where the framework was launched, and three commonly used freeware packages: FreeSurfer, FSL, and SPM. The MRBrainS evaluation framework provides an objective and direct comparison of all evaluated algorithms and can aid in selecting the best performing method for the segmentation goal at hand.This study was financially supported by IMDI Grant 104002002 (Brainbox) from ZonMw, the Netherlands Organisation for Health Research and Development, within kind sponsoring by Philips, the University Medical Center Utrecht, and Eindhoven University of Technology. The authors would like to acknowledge the following members of the Utrecht Vascular Cognitive Impairment Study Group who were not included as coauthors of this paper but were involved in the recruitment of study participants and MRI acquisition at the UMC Utrecht (in alphabetical order by department): E. van den Berg, M. Brundel, S. Heringa, and L. J. Kappelle of the Department of Neurology, P. R. Luijten and W. P. Th. M. Mali of the Department of Radiology, and A. Algra and G. E. H. M. Rutten of the Julius Center for Health Sciences and Primary Care. The research of Geert Jan Biessels and the VCI group was financially supported by VIDI Grant 91711384 from ZonMw and by Grant 2010T073 of the Netherlands Heart Foundation. The research of Jeroen de Bresser is financially supported by a research talent fellowship of the University Medical Center Utrecht (Netherlands). The research of Annegreet van Opbroek and Marleen de Bruijne is financially supported by a research grant from NWO (the Netherlands Organisation for Scientific Research). The authors would like to acknowledge MeVis Medical Solutions AG (Bremen, Germany) for providing MeVisLab. Duygu Sarikaya and Liang Zhao acknowledge their Advisor Professor Jason Corso for his guidance. Duygu Sarikaya is supported by NIH 1 R21CA160825-01 and Liang Zhao is partially supported by the China Scholarship Council (CSC).info:eu-repo/semantics/publishedVersio

Surface cracking in an orthotropic medium subjected to frictional contact

This article presents an analytical method capable of resolving the coupled problem of surface cracking in an orthotropic elastic medium subjected to frictional contact by a rigid flat punch. Reciprocal influences between the surface crack and the flat punch are accounted for by establishing a fully coupled formulation. Governing partial differential equations involving the displacement components are derived in accordance with plane theory of orthotropic elasticity. General solutions corresponding to mode I and II crack problems and contact problem are obtained employing Fourier transformation techniques. These separate solutions are then reconciled; and three coupled singular integral equations are developed by applying crack surface and contact zone conditions. Singular integral equations are solved numerically through an expansion-collocation method in which the primary unknowns are expanded into series in terms of Jacobi polynomials. Comparisons to the results available in the literature for certain special cases do verify the proposed procedures. Further numerical results are presented to be able to demonstrate the influences of material orthotropy, coefficient of friction, and geometric parameters upon the mixed-mode stress intensity factors and the contact stress

Mixed-Mode Fracture Analysis Of Orthotropic Functionally Graded Materials Under Mechanical And Thermal Loads

Mixed-mode fracture problems of orthotropic functionally graded materials (FGMs) are examined under mechanical and thermal loading conditions. In the case of mechanical loading, an embedded crack in an orthotropic FGM layer is considered. The crack is assumed to be loaded by arbitrary normal and shear tractions that are applied to its surfaces. An analytical solution based on the singular integral equations and a numerical approach based on the enriched finite elements are developed to evaluate the mixed-mode stress intensity factors and the energy release rate under the given mechanical loading conditions. The use of this dual approach methodology allowed the verifications of both methods leading to a highly accurate numerical predictive capability to assess the effects of material orthotropy and nonhomogeneity constants on the crack tip parameters. In the case of thermal loading, the response of periodic cracks in an orthotropic FGM layer subjected to transient thermal stresses is examined by means of the developed enriched finite element method. The results presented for the thermally loaded layer illustrate the influences of the material property gradation profiles and crack periodicity on the transient fracture mechanics parameters. (C) 2007 Elsevier Ltd. All rights reserved

Paraoxonase and oxidative stress changes in left and right heart of exhaustively exercised rats

Exhaustive exercise can cause subclinical inflammation to heart, since it is an oxidative tissue that works continuously. The effect of exhaustive exercise on left and right ventricles (LVs, RVs) may be different. It is claimed that paraoxonase-1 (PON1), an antioxidant enzyme, has a cardioprotective effect on oxidative stress. Rats were separated as; non-exercised controls (Con), those euthanized immediately after (E-0) and 24 hours after exhaustive exercise (E-24). Cardiac troponin-I (cTnI), total antioxidant status (TAS), total oxidant status (TOS), PON1 activities and histological findings in LV and RV of the exhausted rats were evaluated. TAS and PON1 levels were lower in LVs compared to RVs of all groups. TOS levels were high in LVs compared to RVs of all groups. In LVs, TAS levels decreased significantly in E-0 group while PON1 activity decreased in E-0 and E-24 groups compared to controls. In LVs, TOS levels decreased significantly in E-0 and E-24 groups, but in RVs decrease was seen only in E-0 group. cTnI levels increased significantly in E-0 group, and decreased to control levels in E-24 group. Considering the histological and biochemical findings, exhaustive exercise affected the heart to the maximum during/just after exhaustion, and LV was influenced more than RV.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The relationship of vitamin D receptor gene polimorphism with bone scintigraphy in peritoneal dialysis patients

44th ERA-EDTA Congress -- JUN 22-24, 2007 -- Barcelona, SPAINWOS: 000253320600853ERA-EDT