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Arterial spin labeling for motor activation mapping at 3T with a 32-channel coil: Reproducibility and spatial accuracy in comparison with BOLD fMRI

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NEUROimage 2011年第1期58卷 157-167页

作者： Raoult, Helene Petr, Jan Bannier, Elise Stamm, Aymeric Gauvrit, Jean-Yves Barillot, Christian Ferre, Jean-Christophe Univ Hosp Rennes Dept Neuroradiol Hop Pontchaillou F-35000 Rennes France INRIA VisAGeS Project Team F-35042 Rennes France INSERM U746 F-35042 Rennes France Univ Rennes 1 CNRS UMR 6074 IRISA F-35042 Rennes France Univ Hosp Rennes F-35043 Rennes France

Functional arterial spin labeling (fASL) is an innovative biomarker of neuronal activation that allows direct and absolute quantification of activation-related CBF and is less sensitive to venous contamination than BOLD fMRI. This study evaluated fASL for motor activation mapping in comparison with BOLD fMRI in terms of involved anatomical area localization, intro-individual reproducibility of location, quantification of neuronal activation, and spatial accuracy. Imaging was performed at 3T with a 32-channel coil and dedicated post-processing tools were used. Twelve healthy right-handed subjects underwent FASL and BOLD fMRI while performing a right hand motor activation task. Three sessions were performed 7 days apart in similar physiological conditions. Our results showed an activation in the left primary hand motor area for all 36 sessions in both fASL and BOLD fMRI. The individual functional maps for fASL demonstrated activation in ipsilateral secondary motor areas more often than the BOLD fMRI maps. This finding was corroborated by the group maps. In terms of activation location. fASL reproducibility was comparable to BOLD fMRI, with a distance between activated volumes of 2.1 mm and an overlap ratio for activated volumes of 0.76, over the 3 sessions. In terms of activation quantification. fASL reproducibility was higher, although not significantly, with a CVintra of 11.6% and an ICC value of 0.75. Functional ASL detected smaller activation volumes than BOLD fMRI but the areas had a high degree of co-localization. In terms of spatial accuracy in detecting activation in the hand motor area, fASL had a higher specificity (43.5%) and a higher positive predictive value (69.8%) than BOLD fMRI while maintaining high sensitivity (90.7%). The high intra-individual reproducibility and spatial accuracy of fASL revealed in the present study will subsequently be applied to pathological subjects. (C) 2011 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Brain Mapping/methods Brain Mapping/methods Cerebrovascular Circulation/physiology Female Functional Laterality/physiology Humans image processing, computer-assisted Individuality Magnetic Resonance Imaging/methods Male Motor Cortex/anatomy & histology Motor Cortex/physiology Oxygen/blood Reproducibility of Results Spin Labels

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Dynamic causal modelling: A critical review of the biophysical and statistical foundations

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NEUROimage 2011年第2期58卷 312-322页

作者： Daunizeau, J. David, O. Stephan, K. E. UCL Inst Neurol Wellcome Trust Ctr Neuroimaging London WC1N 3BG England Univ Zurich Inst Empir Res Econ Lab Social & Neural Syst Res CH-8006 Zurich Switzerland Grenoble Inst Neurosci INSERM U836 Grenoble France Univ Grenoble 1 Grenoble France Univ Hosp Dept Neuroradiol Grenoble France Univ Hosp MRI Unit Grenoble France

The goal of dynamic causal modelling (DCM) of neuroimaging data is to study experimentally induced changes in functional integration among brain regions. This requires (i) biophysically plausible and physiologically interpretable models of neuronal network dynamics that can predict distributed brain responses to experimental stimuli and (ii) efficient statistical methods for parameter estimation and model comparison. These two key components of DCM have been the focus of more than thirty methodological articles since the seminal work of Friston and colleagues published in 2003. In this paper, we provide a critical review of the current state-of-the-art of DCM. We inspect the properties of DCM in relation to the most common neuroimaging modalities (fMRI and EEG/MEG) and the specificity of inference on neural systems that can be made from these data. We then discuss both the plausibility of the underlying biophysical models and the robustness of the statistical inversion techniques. Finally, we discuss potential extensions of the current DCM framework, such as stochastic DCMs, plastic DCMs and field DCMs. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Bayes Theorem Biophysics Brain Mapping/methods Brain Mapping/methods Brain Mapping/statistics & numerical data Brain Mapping/statistics & numerical data Causality Data Interpretation, Statistical Electroencephalography/statistics & numerical data Humans image processing, computer-assisted Magnetic Resonance Imaging/statistics & numerical data Magnetoencephalography Magnetoencephalography Models, Neurological Models, Statistical Reproducibility of Results

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High-throughput feature counting and measurement of roots

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BIOINFORMATICS 2011年第9期27卷 1337-1338页

作者： Naeem, Asad French, Andrew P. Wells, Darren M. Pridmore, Tony P. Univ Nottingham Ctr Plant Integrat Biol Nottingham LE12 5RD England Air Univ Dept Comp Sci Islamabad Pakistan

The original RootTrace tool has proved successful in measuring primary root lengths across time series image data. Biologists have shown interest in using the tool to address further problems, namely counting lateral roots to use as parameters in screening studies, and measuring highly curved roots. To address this, the software has been extended to count emerged lateral roots, and the tracking model extended so that strongly curved and agravitropic roots can be now be recovered. Here, we describe the novel image analysis algorithms and user interface implemented within the RootTrace framework to handle such situations and evaluate the results.

关键词： Algorithms image processing, computer-assisted Models, Biological Plant Roots/growth & development Software User-computer Interface

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Entering Adolescence: Resistance to Peer Influence, Risky Behavior, and Neural Changes in Emotion Reactivity

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NEURON 2011年第5期69卷 1029-1036页

作者： Pfeifer, Jennifer H. Masten, Carrie L. Moore, William E., III Oswald, Tasha M. Mazziotta, John C. Iacoboni, Marco Dapretto, Mirella Univ Oregon Dept Psychol Eugene OR 97403 USA Univ Calif Davis Ctr Mind & Brain Davis CA 95616 USA Univ Calif Los Angeles Ahmanson Lovelace Brain Mapping Ctr Dept Psychiat & Biobehav Sci Los Angeles CA 90095 USA Univ Calif Los Angeles FPR Ctr Culture Brain & Dev Los Angeles CA 90095 USA

Adolescence is often described as a period of heightened reactivity to emotions paired with reduced regulatory capacities, a combination suggested to contribute to risk-taking and susceptibility to peer influence during puberty. However, no longitudinal research has definitively linked these behavioral changes to underlying neural development. Here, 38 neurotypical participants underwent two fMRI sessions across the transition from late childhood (10 years) to early adolescence (13 years). Responses to affective facial displays exhibited a combination of general and emotion-specific changes in ventral striatum (VS), ventromedial PFC, amygdala, and temporal pole. Furthermore, VS activity increases correlated with decreases in susceptibility to peer influence and risky behavior. VS and amygdala responses were also significantly more negatively coupled in early adolescence than in late childhood while processing sad and happy versus neutral faces. Together, these results suggest that VS responses to viewing emotions may play a regulatory role that is critical to adolescent interpersonal functioning.

关键词： Adolescent Adolescent Behavior/physiology Adolescent Behavior/psychology Adolescent Development/physiology Analysis of Variance Brain/physiology Brain Mapping Brain Mapping Child Emotions/physiology Facial Expression Female Humans image processing, computer-assisted Magnetic Resonance Imaging Male Peer Group Photic Stimulation Puberty/physiology Puberty/physiology Puberty/psychology Puberty/psychology Questionnaires Risk-Taking

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Description of a novel grading system to assess the quality of bowel preparation in video capsule endoscopy

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ENDOSCOPY 2011年第5期43卷 406-411页

作者： Van Weyenberg, S. J. B. De Leest, H. T. J. I. Mulder, C. J. J. Vrije Univ Amsterdam Med Ctr Dept Gastroenterol & Hepatol NL-1081 HV Amsterdam Netherlands

Background and study aims: Inadequate bowel preparation negatively influences the reliability of examinations by video capsule endoscopy (VCE). Currently, only subjective scales are available to describe mucosal visibility. We aimed to design a score that was derived directly from the VCE images. Patients and methods: A computed assessment of cleansing score was developed based on color intensities of the tissue color bar. The feasibility of this score was retrospectively tested in 24 VCE studies. A prospective study was conducted using 40 VCE segments from 10 consecutive VCE studies. The computed scores were compared with three existing methods of assessing small-intestinal cleansing. Correlations between the existing scoring systems and the computed score were evaluated using the intra-class correlation coefficient and Spearman's rho correlation. Results: All computed measurements were obtained twice and resulted in exactly the same results. Both overall and segmental mucosal visibility could be assessed. The computed score and the 10-point quantitative index were significantly associated for both readers (Spearman's rho: 0.68 and 0.75, respectively;P < 0.001). The intra-class correlation coefficient for the 4-point qualitative evaluation and the computed score was 0.67 for reader 1 and 0.64 for reader 2. For reader 1, the mean computed score for segments assessed as either inadequately or adequately cleansed was 5.0 and 6.4 (P = 0.001). For reader 2 these values were 4.0 and 6.3, respectively (P = 0.005). Conclusions: A computed assessment of small-bowel mucosal visibility based on the ratio of color intensities of the red and green channel of the tissue color bar is feasible and more reproducible than existing subjective scales. Such a computed scale could be integrated into VCE reading software. For this novel scoring system we propose the term Computed Assessment of Cleansing (CAC) score.

关键词： Capsule Endoscopy/methods Feasibility Studies Humans image processing, computer-assisted Intestinal Mucosa Pilot Projects Prospective Studies Retrospective Studies Retrospective Studies

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Relationship Between Renal Parenchymal Volume and Single Kidney Glomerular Filtration Rate Before and After Unilateral Nephrectomy

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UROLOGY 2011年第6期77卷 1404-1408页

作者： Funahashi, Yasuhito Hattori, Ryohei Yamamoto, Tokunori Kamihira, Osamu Sassa, Naoto Gotoh, Momokazu Nagoya Univ Grad Sch Med Dept Urol Showa Ku Nagoya Aichi 4668550 Japan Komaki City Hosp Dept Urol Aichi Japan

OBJECTIVES To measure the renal parenchymal volume (RPV) before and after unilateral nephrectomy and investigate the relationship between the RPV and single kidney glomerular filtration rate (GFR). METHODS From November 2003 to August 2009, 183 patients who had undergone unilateral nephrectomy were enrolled in the present study. All patients had undergone preoperative technetium-99m dimercaptosuccinic acid renal scintigraphy. Contrast-enhanced computed tomography was performed before and 6 months after surgery. RPV was calculated as the normally functioning tissue, excluding tumors or nonenhanced areas, using a 3-dimensional image reconstruction program. RESULTS The mean split GFR of the remaining kidney increased by 21.2%, from 41.6 to 49.5 mL/min/1.73 m(2) at 6 months after nephrectomy. The mean RPV of the remaining kidney increased by 9.3%, from 164.2 to 178.8 cm(3) after nephrectomy. The preoperative relative RPV of the remaining kidney was 58.8% (range 37.2%-97.9%) and the technetium-99m dimercaptosuccinic acid uptake was 62.2% (range 39.6%-100%), indicating a significant linear correlation (R = 0.865, P < .001). RPV correlated well with the single kidney GFR and patient age, both preoperatively and postoperatively. The postoperative GFR could be predicted by combining the preoperative factors. Multivariate regression analysis revealed that the RPV was positively associated with the single kidney GFR and negatively associated with patient age. CONCLUSIONS The differential renal function correlated well with the RPV and can be estimated by calculating the RPV. Even without using renal scintigraphy, the postoperative GFR can be predicted using our established formula. UROLOGY 77: 1404-1408, 2011. (C) 2011 Elsevier Inc.

关键词： Aged Contrast Media/pharmacology Contrast Media/pharmacology Creatinine/metabolism Female Glomerular Filtration Rate Humans image processing, computer-assisted Kidney/metabolism Kidney/pathology Male Medical Oncology/methods Middle Aged Nephrectomy/methods Radionuclide Imaging/methods Technetium Tc 99m Dimercaptosuccinic Acid/pharmacology Technetium Tc 99m Dimercaptosuccinic Acid/pharmacology Tomography, X-Ray Computed/methods

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Ribosome Assembly Factors Prevent Premature Translation Initiation by 40S Assembly Intermediates

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SCIENCE 2011年第6048期333卷 1449-1453页

作者： Strunk, Bethany S. Loucks, Cherisse R. Su, Min Vashisth, Harish Cheng, Shanshan Schilling, Justin Brooks, Charles L., III Karbstein, Katrin Skiniotis, Georgios Scripps Res Inst Dept Canc Biol Jupiter FL 33458 USA Univ Michigan Chem Biol Doctoral Program Ann Arbor MI 48109 USA Univ Michigan Inst Life Sci Sch Med Ann Arbor MI 48109 USA Univ Michigan Dept Biol Chem Sch Med Ann Arbor MI 48109 USA Univ Michigan Dept Chem Ann Arbor MI 48109 USA Univ Michigan Dept Biophys Ann Arbor MI 48109 USA Univ Michigan Ctr Computat Med & Bioinformat Ann Arbor MI 48109 USA

Ribosome assembly in eukaryotes requires approximately 200 essential assembly factors (AFs) and occurs through ordered events that initiate in the nucleolus and culminate in the cytoplasm. Here, we present the electron cryo-microscopy (cryo-EM) structure of a late cytoplasmic 40S ribosome assembly intermediate from Saccharomyces cerevisiae at 18 angstrom resolution. We obtained cryo-EM reconstructions of preribosomal complexes lacking individual components to define the positions of all seven AFs bound to this intermediate. These late-binding AFs are positioned to prevent each step in the translation initiation pathway. Together, they obstruct the binding sites for initiation factors, prevent the opening of the messenger RNA channel, block 60S subunit joining, and disrupt the decoding site. These redundant mechanisms probably ensure that pre-40S particles do not enter the translation pathway, which would result in their rapid degradation.

关键词： Binding Sites Cryoelectron Microscopy Eukaryotic Initiation Factor-1/chemistry Eukaryotic Initiation Factor-1/metabolism Eukaryotic Initiation Factor-3/chemistry Eukaryotic Initiation Factor-3/metabolism image processing, computer-assisted Methyltransferases/chemistry Methyltransferases/metabolism Models, Molecular Nuclear Proteins/chemistry Nuclear Proteins/metabolism Peptide Chain Initiation, Translational Protein-Serine-Threonine Kinases/chemistry Protein-Serine-Threonine Kinases/metabolism Ribosomal Proteins/chemistry Ribosomal Proteins/metabolism Ribosome Subunits, Small, Eukaryotic/chemistry Ribosome Subunits, Small, Eukaryotic/metabolism Ribosome Subunits, Small, Eukaryotic/ultrastructure RNA, Fungal/genetics RNA, Fungal/metabolism RNA, Messenger/genetics RNA, Messenger/metabolism Saccharomyces cerevisiae/chemistry Saccharomyces cerevisiae/genetics Saccharomyces cerevisiae/metabolism Saccharomyces cerevisiae Proteins/chemistry Saccharomyces cerevisiae Proteins/metabolism

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Three-Dimensional Model of Salmonella's Needle Complex at Subnanometer Resolution

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SCIENCE 2011年第6021期331卷 1192-1195页

作者： Schraidt, Oliver Marlovits, Thomas C. Res Inst Mol Pathol A-1030 Vienna Austria Austrian Acad Sci Inst Mol Biotechnol A-1030 Vienna Austria

Type III secretion systems (T3SSs) are essential virulence factors used by many Gram-negative bacteria to inject proteins that make eukaryotic host cells accessible to invasion. The T3SS core structure, the needle complex (NC), is a similar to 3.5 megadalton-sized, oligomeric, membrane-embedded complex. Analyzing cryo-electron microscopy images of top views of NCs or NC substructures from Salmonella typhimurium revealed a 24-fold symmetry for the inner rings and a 15-fold symmetry for the outer rings, giving an overall C3 symmetry. Local refinement and averaging showed the organization of the central core and allowed us to reconstruct a subnanometer composite structure of the NC, which together with confident docking of atomic structures reveal insights into its overall organization and structural requirements during assembly.

关键词： Bacterial Proteins/chemistry Bacterial Proteins/ultrastructure Bacterial Secretion Systems Cryoelectron Microscopy Crystallography, X-Ray image processing, computer-assisted Membrane Proteins/chemistry Membrane Proteins/ultrastructure Membrane Transport Proteins/chemistry Membrane Transport Proteins/ultrastructure Models, Molecular Mutation Protein Conformation Protein Structure, Tertiary Salmonella typhimurium/chemistry

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Sonographic assessment of arterial frequency and distribution within the brachial plexus: a comparison with the cadaveric record

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ANAESTHESIA 2011年第10期66卷 931-935页

作者： Nambyiah, P. Umbarje, K. Amir, R. Parikh, M. Oosthuysen, S. A. VR. Norfolk & Norwich Univ Hosp Dept Anaesthesia Norwich Norfolk England Addenbrookes Hosp Dept Anaesthesia Cambridge England Walsall Healthcare NHS Trust Walsall W Midlands England Goyal Hosp & Res Ctr Jodhpur Rajasthan India

We investigated the number and distribution of arteries within the brachial plexus territory using a portable ultrasound device, and compared these findings with known cadaveric data. We recruited 200 volunteers and carried out 400 brachial plexus examinations in a prospective observational study design. We identified arteries within the brachial plexus in more than 90% of subjects. Most of these were located in the upper and middle zones of the plexus and therefore lie within the possible path of a block needle. These findings correlate well with previous cadaveric studies, suggesting that arteries within the brachial plexus territory can be reliably identified with a portable ultrasound device. The presence of these vessels may impact upon the safety and efficacy of brachial plexus blockade. Routine pre-procedural sonographic assessment may offer improved safety and efficacy.

关键词： Adolescent Arteries/anatomy & histology Arteries/ultrasonography Brachial Plexus/blood supply Brachial Plexus/ultrasonography Cadaver Cross-Sectional Studies Female Humans image processing, computer-assisted Male Nerve Block/instrumentation Prospective Studies Regional Blood Flow Ultrasonography, Doppler, Color

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Simple Neurite Tracer: open source software for reconstruction, visualization and analysis of neuronal processes

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BIOINFORMATICS 2011年第17期27卷 2453-2454页

作者： Longair, Mark H. Baker, Dean A. Armstrong, J. Douglas Uni ETH Zurich Inst Neuroinformat CH-8057 Zurich Switzerland Univ Cambridge Dept Genet Cambridge CB2 3EH England Univ Edinburgh Inst Adapt & Neural Computat Sch Informat Edinburgh EH8 9AB Midlothian Scotland

Motivation: Advances in techniques to sparsely label neurons unlock the potential to reconstruct connectivity from 3D image stacks acquired by light microscopy. We present an application for semiautomated tracing of neurons to quickly annotate noisy datasets and construct complex neuronal topologies, which we call the Simple Neurite Tracer.

关键词： Animals computer Graphics Humans image processing, computer-assisted Imaging, Three-Dimensional Neurites/ultrastructure Neurons/cytology Software

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