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Machine-learning techniques for building a diagnostic model for very mild dementia

NEUROimage 2010年第1期52卷 234-244页

作者： Chen, Rong Herskovits, Edward H. Univ Penn Dept Radiol Philadelphia PA 19104 USA

Many researchers have sought to construct diagnostic models to differentiate individuals with very mild dementia (VMD) from healthy elderly people, based on structural magnetic-resonance (MR) images These models have, for the most part, been based on discriminant analysis or logistic regression, with few reports of alternative approaches To determine the relative strengths of different approaches to analyzing structural MR data to distinguish people with VMD from normal elderly control subjects, we evaluated seven different classification approaches, each of which we used to generate a diagnostic model from a training data set acquired from 83 subjects (33 VMD and 50 control) We then evaluated each diagnostic model using an independent data set acquired from 30 subjects (13 VMD and 17 controls) We found that there were significant performance differences across these seven diagnostic models Relative to the diagnostic models generated by discriminant analysis and logistic regression, the diagnostic models generated by other high-performance diagnostic-model generation algorithms manifested increased generalizability when diagnostic models were generated from all atlas structures. (C) 2010 Elsevier Inc. All rights reserved

关键词： Aged Algorithms Artificial Intelligence Atlases as Topic Brain/pathology Databases as Topic Dementia/diagnosis Dementia/pathology Diagnosis, computer-assisted/methods Discriminant Analysis Female Humans image processing, computer-assisted/methods Logistic Models Magnetic Resonance Imaging Male Models, Neurological Sensitivity and Specificity Temporal Lobe/pathology

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An automated strategy for the delineation and parcellation of commissural pathways suitable for clinical populations utilising high angular resolution diffusion imaging tractography

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NEUROimage 2010年第3期50卷 1044-1053页

作者： Pannek, Kerstin Mathias, Jane L. Bigler, Erin D. Brown, Greg Taylor, Jamie D. Rose, Stephen Univ Queensland Clin Res Ctr Brisbane Qld 4029 Australia Univ Queensland Ctr Magnet Resonance Brisbane Qld 4029 Australia Univ Adelaide Sch Psychol Adelaide SA Australia Brigham Young Univ Dept Psychol & Neurosci Provo UT 84602 USA Royal Adelaide Hosp Magnet Resonance Imaging Unit Adelaide SA 5000 Australia Univ Queensland Ctr Med Diagnost Technol Queensland St Lucia Qld Australia

There is a growing interest in understanding;alterations to the interhemispheric transfer of information as a result of brain injury and neurological disease. To facilitate research, we have developed a fully automated method for the accurate extraction of commissural pathways (corpus callosum (CC) and anterior commissure (AC)) and functional parcellation of the CC using a high angular resolution diffusion imaging (HARDI) based probabilistic tractography approach that is applicable to clinical populations. The CC was divided into 33 functional divisions based on its connections to cortical parcellations derived from individual structural images in 8 healthy participants. Probabilistic CC population maps acquired at two different b-values (1000 S mm(-2) and 3000 s mm(-2)) are presented. Topography of the CC was consistent with histology reports. We show that HARD1 data acquired at a higher b-value reveals more callosal-temporal connections than low b-value data. With respect to intra-subject precision, data acquired using a higher b-value show superior reproducibility of the delineated CC area on the midsagittal plane (MSP), as well as the total number of callosal streamlines and the number of clustered callosal streamlines. The AC was delineated in all 8 participants using high b-value HARDI tractography. Cortical projections of the AC were analysed and are in agreement with known anatomy. We conclude that, while data acquired at a lower b-value may be used, this is associated with a loss in quality, both in the delineation of commissural pathways and, potentially, the reproducibility of results over time. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Adolescent Adult Aged Automation Brain/anatomy & histology Diffusion Magnetic Resonance Imaging/methods Female Humans image processing, computer-assisted/methods Male Middle Aged Neural Pathways/anatomy & histology Probability Reproducibility of Results Time Factors

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Voxel-based Bayesian lesion-symptom mapping

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NEUROimage 2010年第1期49卷 597-602页

作者： Chen, Rong Herskovits, Edward H. Univ Penn Dept Radiol Philadelphia PA 19104 USA

Most existing voxel-based lesion-symptom mapping methods are based on the same statistical foundation: null hypothesis significance testing (NHST). The two major limitations of these methods are the inability to infer that there is no difference in lesion proportions, and a requirement for multiple-comparison correction. We propose a Bayesian approach that directly models the posterior distribution of lesion-proportion difference, and makes decisions based on inference on this posterior distribution. Compared to NHST-based approaches, our Bayesian approach yields inference results with clearer semantics, and does not require multiple-comparison correction. We evaluated Our Bayesian method using simulated data, and data from a study of acute ischemic left-hemispheric stroke. Results of both experiments indicate that the Bayesian approach is sensitive in detecting regions that characterize group differences. (C) 2009 Elsevier Inc. All Fights reserved.

关键词： Algorithms Bayes Theorem Brain Ischemia/pathology Cerebrovascular Circulation computer Simulation Diffusion Magnetic Resonance Imaging Functional Laterality/physiology Humans image processing, computer-assisted/methods Models, Statistical Stroke/pathology

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A hybrid approach to automatic clustering of white matter fibers

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NEUROimage 2010年第2期49卷 1249-1258页

作者： Li, Hai Xue, Zhong Guo, Lei Liu, Tianming Hunter, Jill Wong, Stephen T. C. Cornell Univ Med Image Anal Lab Ctr Bioengn & Informat Methodist HospRes Inst Houston TX USA Cornell Univ Dept Radiol Methodist Hosp Weill Med Coll Houston TX USA Univ Georgia Dept Comp Sci Athens GA 30602 USA Univ Georgia Bioimaging Res Ctr Athens GA 30602 USA Texas Childrens Hosp Neuroradiol Sect Dept Radiol Houston TX 77030 USA

Recently, the tract-based white matter (WM) fiber analysis has been recognized as an effective framework to study the diffusion tensor imaging (DTI) data of human brain. This framework can provide biologically meaningful results and facilitate the tract-based comparison across subjects. However, due to the lack of quantitative definition of WM bundle boundaries, the complexity of brain architecture and the variability of WM shapes, clustering WM fibers into anatomically meaningful bundles is nontrivial. In this paper, we propose a hybrid top-down and bottom-up approach for automatic clustering and labeling of WM fibers, which utilizes both brain parcellation results and similarities between WM fibers. Our experimental results show reasonably good performance of this approach in clustering WM fibers into anatomically meaningful bundles. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Algorithms Automation Brain/anatomy & histology Cluster Analysis Databases as Topic Diffusion Tensor Imaging/methods Diffusion Tensor Imaging/methods Fuzzy Logic Humans image processing, computer-assisted/methods Nerve Fibers, Myelinated Neural Pathways/anatomy & histology Organ Size

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Imagine that! ERPs provide evidence for distinct hemispheric contributions to the processing of concrete and abstract concepts

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NEUROimage 2010年第1期49卷 1116-1123页

作者： Huang, Hsu-Wen Lee, Chia-Lin Federmeier, Kara D. Univ Illinois Dept Psychol Champaign IL 61820 USA Univ Illinois Program Neurosci Champaign IL 61820 USA Univ Illinois Beckman Inst Adv Sci & Technol Champaign IL 61820 USA

Although abstract and concrete concepts are processed and remembered differently, the underlying nature of those differences remains in dispute. The current study used visual half-field (VF) presentation methods and event-related potential (ERP) measures to examine how the left (LH) and right (RH) cerebral hemispheres process concrete and abstract meanings of polysemous nouns (e.g., "green book," referring to the concrete, physical object that is a book, versus "engaging book," referring to the abstract information that a book conveys). With presentation to the right VF, nouns preceded by concrete modifiers were associated with more positivity on the P2 and N400, suggesting that concrete concepts were easier for the LH to process perceptually and semantically. In contrast, with presentation to the left VF (RH), nouns used in a concrete sense elicited a sustained frontal negativity (500-900 ms) that has been previously linked to imagery. The results thus reveal multiple, distinct neural and cognitive sources for concreteness effects and point to a critical role for the RH in linking language input to sensory imagery. (C) 2009 Elsevier Inc. All Fights reserved.

关键词： Adolescent Adult Brain/physiology Brain Mapping Brain Mapping Electroencephalography Evoked Potentials/physiology Executive Function/physiology Female Functional Laterality/physiology Humans image processing, computer-assisted/methods Imagination/physiology Male Mental Processes/physiology Photic Stimulation Psycholinguistics Psychomotor Performance/physiology Reading Visual Fields/physiology Young Adult

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Reproducibility of thalamic segmentation based on probabilistic tractography

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NEUROimage 2010年第1期52卷 69-85页

作者： Traynor, Catherine Heckemann, Rolf A. Hammers, Alexander O'Muircheartaigh, Jonathan Crum, William R. Barker, Gareth J. Richardson, Mark P. Kings Coll London Inst Psychiat Dept Clin Neurosci London England Kings Coll London Inst Psychiat Dept Neuroimaging London England Univ London Imperial Coll Sci Technol & Med MRC Clin Sci Ctr Fac Med London SW7 2AZ England Neurodis Fdn Lyon France

Reliable identification of thalamic nuclei is required to improve targeting of electrodes used in Deep Brain Stimulation (DBS), and for exploring the role of thalamus in health and disease A previously described method using probabilistic tractography to segment the thalamus based on connections to cortical target regions was implemented Both within- and between-subject reproducibility were quantitatively assessed by the overlap of the resulting segmentations, the effect of two different numbers of target regions (6 and 31) on reproducibility of the segmentation results was also investigated Very high reproducibility was observed when a single dataset was processed multiple times using different starting conditions Thalamic segmentation was also very reproducible when multiple datasets from the same subject were processed using six cortical target regions Within-subject reproducibility was reduced when the number of target regions was increased, particularly in medial and posterior regions of the thalamus A large degree of overlap in segmentation results from different subjects was obtained, particularly in thalamic regions classified as connecting to frontal, parietal, temporal and pre-central cortical target regions (C) 2010 Elsevier Inc All rights reserved

关键词： Adult Algorithms Cerebral Cortex/anatomy & histology Databases as Topic Female Functional Laterality Fuzzy Logic Humans image processing, computer-assisted/methods Male Middle Aged Neural Pathways/anatomy & histology Organ Size Probability Reproducibility of Results Software Thalamus/anatomy & histology Young Adult

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Single-trial coupling of the gamma-band response and the corresponding BOLD signal

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NEUROimage 2010年第3期49卷 2238-2247页

作者： Mulert, C. Leicht, G. Hepp, P. Kirsch, V. Karch, S. Pogarell, O. Reiser, M. Hegerl, U. Jaeger, L. Moller, H. J. McCarley, R. W. Univ Munich Dept Psychiat & Psychotherapy D-80336 Munich Germany Harvard Univ Dept Psychiat Sch Med Brockton MA 02401 USA VA Boston Healthcare Syst Brockton MA USA Univ Med Ctr Hamburg Eppendorf Ctr Psychosocial Med Dept Psychiat & Psychotherapy Hamburg Germany Univ Munich Inst Clin Radiol D-80336 Munich Germany Univ Leipzig Dept Psychiat & Psychotherapy Leipzig Germany

Oscillations in the gamma-band frequency range have been described to be more closely connected to hemodynamic changes as assessed with functional magnetic resonance imaging (fMRI) than other aspects of neuronal activity. In addition. gamma-band oscillations have attracted much interest during the last few years since they are thought to play a Crucial role in many aspects of brain function related to perception and cognition. It was the aim of the present simultaneous EEG-fMRI Study to identify brain regions specifically involved in the generation of the auditory gamma-band response (GBR) using single-trial coupling of EEG and fMRI. Ten healthy Subjects participated in this study Three different runs of an auditory choice reaction task with increasing difficulty were performed Brain activity was recorded simultaneously with high density FEG (61 channels) and fMRI (1.5 T). BOLD correlates of the GBR have been predicted using the sing-le-trial amplitude of the GBR Reaction times (p<0.001). error rates (p<005) and self-ratings of task difficulty and effort demands (p<0.001) were related to the level of difficulty in the task In addition,we found a significant influence of task difficulty oil the amplitude of the GBR at Cz (p<0.05). Using single-trial Coupling of EEG and fMRI GBR-specific activations were found only in the auditory cortex, the thalamus and the anterior cingulate cortex (ACC) in the most difficult run. Single-trial coupling might be a useful method in order to increase our knowledge about the functional neuroanatomy of "neural ensembles" coupled by 40 Hz oscillations (C) 2009 Elsevier Inc. All rights reserved

关键词： Acoustic Stimulation Adult Brain/anatomy & histology Brain/physiology Brain Mapping/methods Brain Mapping/methods Electroencephalography Evoked Potentials, Auditory/physiology Female Humans image processing, computer-assisted/methods Magnetic Resonance Imaging Male Neural Pathways/anatomy & histology Neural Pathways/physiology Reaction Time/physiology Signal processing, computer-assisted Young Adult

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Early detection of the chemical changes occurring during the induction and prevention of autoimmune-mediated demyelination detected by FT-IR imaging

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NEUROimage 2010年第2期49卷 1180-1189页

作者： Heraud, Philip Caine, Sally Campanale, Naomi Karnezis, Tara McNaughton, Don Wood, Bayden R. Tobin, Mark J. Bernard, Claude C. A. Monash Univ Multiple Sclerosis Res Grp Monash Immunol & Stem Cell Labs Clayton Vic 3800 Australia Monash Univ Ctr Biospectroscopy Clayton Vic 3800 Australia Monash Univ Sch Chem Clayton Vic 3800 Australia Royal Melbourne Hosp Ludwig Inst Canc Res Melbourne Vic 3050 Australia Australian Synchrotron Melbourne Vic 3168 Australia

Multiple sclerosis (MS) is an inflammatory, demyelinating and neurodegenerative disease of the central nervous system (CNS). Despite progress in understanding immunogenetic aspects of this disease, the mechanisms involved in lesion formation are unknown. To gain new insights into the neuropathology of MS, we used an innovative integration of Fourier transform infrared (FT-IR) microspectroscopy, bioinformatics, and a synchrotron light source to analyze macromolecular changes in the CNS during the course and prevention of experimental autoimmune encephalomyelitis (EAE), an animal model for MS. We report that subtle chemical and structural changes not observed by conventional histology were detected before the onset of clinical signs of EAE. Moreover, trained artificial neural networks (ANNs) could discriminate, with excellent sensitivity and specificity, pathology from surrounding tissues and the early stage of the disease progression. Notably, we show that this novel measurement platform can detect characteristic differences in biochemical composition of lesion pathology in animals partially protected against EAE by vaccination with Nogo-A, an inhibitor of neural outgrowth, demonstrating the potential for automated screening and evaluation of new therapeutic agents. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Animals Automation Disease Models, Animal Disease Progression Encephalomyelitis, Autoimmune, Experimental/metabolism Encephalomyelitis, Autoimmune, Experimental/metabolism Encephalomyelitis, Autoimmune, Experimental/pathology Encephalomyelitis, Autoimmune, Experimental/pathology Encephalomyelitis, Autoimmune, Experimental/therapy Encephalomyelitis, Autoimmune, Experimental/therapy Female image processing, computer-assisted/methods Mice Mice, Inbred C57BL Multiple Sclerosis Myelin Proteins/immunology Myelin Proteins/therapeutic use Neural Networks (computer) Peptides/immunology Peptides/therapeutic use Sensitivity and Specificity Spectroscopy, Fourier Transform Infrared/methods Time Factors Vaccination

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Diffuse damage in pediatric traumatic brain injury: A comparison of automated versus operator-controlled quantification methods

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NEUROimage 2010年第3期50卷 1017-1026页

作者： Bigler, Erin D. Abildskov, Tracy J. Wilde, Elisabeth A. McCauley, Stephen R. Li, Xiaoqi Merkley, Tricia L. Fearing, Michael A. Newsome, Mary R. Scheibel, Randall S. Hunter, Jill V. Chu, Zili Levin, Harvey S. Brigham Young Univ Dept Psychol Provo UT 84602 USA Brigham Young Univ Ctr Neurosci Provo UT 84602 USA Univ Utah Dept Psychiat Salt Lake City UT USA Univ Utah Utah Brain Inst Salt Lake City UT USA Baylor Coll Med Dept Radiol Houston TX 77030 USA Baylor Coll Med Dept Neurol Houston TX 77030 USA Univ Texas Houston Sch Med Houston TX USA Baylor Coll Med Dept Pediat Hematol Oncol Sect Houston TX 77030 USA Hebrew SeniorLife Dept Med Neuropyschol Boston MA USA Texas Childrens Hosp EB Singleton Dept Diagnost Imaging Houston TX 77030 USA Baylor Coll Med Dept Neurol Houston TX 77030 USA Baylor Coll Med Dept Neurosurg Houston TX 77030 USA Michael E De Bakey Vet Affairs Med Ctr Houston TX USA

This investigation had two main objectives: 1) to assess the comparability Of volumes determined by operator-controlled image quantification with automated image analysis in evaluating atrophic brain changes related to traumatic brain injury (TBI) in children, and 2) to assess the extent of diffuse structural changes throughout the brain as determined by reduced volume of a brain Structure or region of interest (ROI). Operator-control led methods used ANALYZE (R) software for segmentation and tracing routines of pre-defined brain structures and Rots. For automated image analyses, the open-access FreeSurfer program was used. Sixteen children with moderate-to-severe TBI were compared to individually matched, typically developing control children and the Volumes of 18 brain structures and/or ROIs were compared between the two methods. Both methods detected atrophic changes but differed in the magnitude of the atrophic effect with the best agreement in subcortical Structures. The volumes of all brain structures/ROIs were smaller in the TBI group regardless of method used;overall effect size differences were minimal for caudate and putamen but moderate to large for all other measures. This is reflective of the diffuse nature of TBI and its widespread impact on structural brain integrity, indicating that both FreeSurfer and operator-control led methods can reliably assess cross-sectional volumetric changes in pediatric TBI. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Adolescent Age Factors Automation Brain/pathology Brain Injuries/pathology Brain Injuries/pathology Caudate Nucleus/pathology Child Child, Preschool Female Humans image processing, computer-assisted/methods Infant Magnetic Resonance Imaging/methods Male Observer Variation Organ Size Putamen/pathology Severity of Illness Index Severity of Illness Index Software

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Whole-brain anatomical networks: Does the choice of nodes matter?

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NEUROimage 2010年第3期50卷 970-983页

作者： Zalesky, Andrew Fornito, Alex Harding, Ian H. Cocchi, Luca Yuecel, Murat Pantelis, Christos Bullmore, Edward T. Univ Melbourne Melbourne Neuropsychiat Ctr Dept Psychiat Melbourne Vic Australia Melbourne Hlth Melbourne Vic Australia Univ Melbourne Dept Elect & Elect Engn Melbourne Sch Engn Melbourne Vic Australia Univ Cambridge Dept Psychiat Behav & Clin Neurosci Inst Cambridge England Univ Melbourne Orygen Youth Hlth Res Ctr Ctr Youth Mental Hlth Melbourne Vic Australia

Whole-brain anatomical connectivity in living humans can be modeled as a network with diffusion-MRI and tractography. Network nodes are associated with distinct grey-matter regions, while white-matter fiber bundles serve as interconnecting network links. However, the lack of a gold standard for regional parcellation in brain MRI makes the definition of nodes arbitrary, meaning that network nodes are defined using templates employing either random or anatomical parcellation criteria. Consequently, the number of nodes included in networks studied by different authors has varied considerably, from less than 100 up to more than 10(4). Here, we systematically and quantitatively assess the behavior, structure and topological attributes of whole-brain anatomical networks over a wide range of nodal scales, a variety of grey-matter parcellations as well as different diffusion-MRI acquisition protocols. We show that simple binary decisions about network Organization, such as whether small-worldness or scale-freeness is evident, are unaffected by spatial scale, and that the estimates of various organizational parameters (e.g. small-worldness, clustering, path length, and efficiency) are consistent across different parcellation scales at the same resolution (i.e. the same number of nodes). However, these parameters vary considerably as a function of spatial scale;for example small-worldness exhibited a difference of 95% between the widely-used automated anatomical labeling (AAL) template (similar to 100 nodes) and a 4000-node random parcellation (sigma(AAL)=1.9 vs. sigma(4000) = 53.6 +/- 2.2). These findings indicate that any comparison of network parameters across studies must be made with reference to the spatial scale of the nodal parcellation. (C) 2009 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Brain/anatomy & histology Diffusion Magnetic Resonance Imaging/methods Diffusion Tensor Imaging/methods Diffusion Tensor Imaging/methods Female Humans image processing, computer-assisted/methods Least-Squares Analysis Male Nerve Fibers, Unmyelinated Neural Pathways/anatomy & histology Young Adult

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