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Quantitative angiographic analysis of right ventricular global function in normal Incidences and in patients with coronary artery disease

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ANGIOLOGY 2005年第2期56卷 137-142页

作者： Batyraliev, TA Pershukov, IV Birand, A Erenler, O Sani Konukoglu Med Ctr Gaziantep Turkey Reg Clin Hosp Voronezh Russia Cukurova Univ Adana Turkey

At present right ventriculography data cannot be accurately estimated owing to the absence of software for quantitative analysis of the right ventricle (RV) volumes and function. The aim of this study was to use existing software for left ventriculography analysis to estimate right ventricular volumes and function in patients without coronary lesions and in those with coronary artery disease (CAD). Thirty-two patients without significant lesions of coronary arteries and 20 patients with CAD were examined with left ventriculography and right atriography. Each examination was performed in 2 projections: 30 degrees right anterior oblique (RAO 30 degrees) and 600 left anterior oblique (LAO 60 degrees) projections. Correction factor (CF) was obtained by finding the ratio between stroke volumes of the left and right ventricles, The mean CF was 0.9243 +/- 0.2887 for patients without CAD and 0.8758 +/- 0.2232 for patients with CAD. Such calculation is the easiest and quite accurate method of determining RV volumes and function by using existing software of quantitative angiographic analysis.

关键词： Adult Aged Coronary Angiography/statistics & numerical data Coronary Angiography/statistics & numerical data Coronary Disease/radiography data Interpretation, Statistical Female Humans image processing, computer-assisted/statistics & numerical data Male Middle Aged Prognosis Reference Values Sensitivity and Specificity Software Stroke Volume/physiology Ventricular Dysfunction, Left/radiography Ventricular Dysfunction, Right/radiography Ventricular Function, Left/physiology Ventricular Function, Right/physiology Ventriculography, First-Pass/statistics & numerical data Ventriculography, First-Pass/statistics & numerical data

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Towards natural stimulation in MRI - Issues of data analysis

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NEUROimage 2007年第1期35卷 131-139页

作者： Malinen, Sanna Hlushchuk, Yevhen Hari, Riitta Helsinki Univ Technol Brain Res Unit Low Temp Lab FI-02015 Espoo Finland Helsinki Univ Technol Adv Magnet Imaging Ctr FI-02015 Espoo Finland Univ Helsinki Ctr Neurosci FI-00290 Helsinki Finland

in search for suitable tools to study brain activation in natural environments, where the stimuli are multimodal, poorly predictable and irregularly varying, we collected functional magnetic resonance imaging data from 6 subjects during a continuous 8-min stimulus sequence that comprised auditory (speech or tone pips), visual (video clips dominated by faces, hands, or buildings), and tactile finger stimuli in blocks of 6-33 s. Results obtained by independent component analysis (ICA) and general-linear-model-based analysis (GLM) were compared. ICA separated in the superior temporal gyros one independent component (IC) that reacted to all auditory stimuli and in the superior temporal sulcus another IC responding only to speech. Several distinct and rather symmetric vision-sensitive ICs were found in the posterior brain. An IC in the V5/MT region reacted to videos depicting faces or hands, whereas ICs in the V1/V2 region reacted to all video clips, including buildings. The corresponding GLM-derived activations in the auditory and early visual cortices comprised sub-areas of the ICA-revealed activations. ICA separated a prominent IC in the primary somatosensory cortex whereas the GLM-based analysis failed to show any touch-related activation. "Intrinsic" components, unrelated to the stimuli but spatially consistent across subjects, were discerned as well. The individual time courses were highly consistent in sensory projection cortices and more variable elsewhere. The ability to differentiate functionally meaningful composites of activated brain areas and to straightforwardly reveal their temporal dynamics renders ICA a sensitive tool to study brain responses to complex natural stimuli. (c) 2006 Elsevier Inc. All rights reserved.

关键词： Acoustic Stimulation Adult Brain/anatomy & histology Cerebrovascular Circulation data Interpretation, Statistical Female Hearing/physiology Humans image processing, computer-assisted/statistics & numerical data Magnetic Resonance Imaging/statistics & numerical data Male Photic Stimulation Physical Stimulation Principal Component Analysis Touch/physiology Vision, Ocular/physiology

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Labeling of ambiguous subvoxel fibre bundle configurations in high angular resolution diffusion MRI

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NEUROimage 2008年第1期41卷 58-68页

作者： Savadjiev, Peter Campbell, Jennifer S. W. Descoteaux, Maxime Deriche, Rachid Pike, G. Bruce Siddiqi, Kaleem McGill Univ Ctr Intelligent Machines Montreal PQ Canada McGill Univ Sch Comp Sci Montreal PQ Canada McGill Univ McConnell Brain Imaging Ctr Montreal Neurol Inst Montreal PQ Canada INRIA Sophia Antipolis Project Team Odyssee Sophia Antipolis France

Whereas high angular resolution reconstruction methods for diffusion MRI can estimate multiple dominant fibre orientations within a single imaging voxel, they are fundamentally limited in certain cases of complex subvoxel fibre structures, resulting in ambiguous local orientation distribution functions. In this article we address the important problem of disambiguating such complex subvoxel fibre tract configurations, with the purpose of improving the performance of fibre tractography. We do so by extending a curve inference method to distinguish between the cases of curving and fanning fibre bundles using differential geometric estimates in a local neighbourhood. The key benefit of this method is the inference of curves, instead of only fibre orientations, to model the underlying fibre bundles. This in turn allows distinct fibre geometries that contain nearly identical sets of fibre orientations at a voxel, to be distinguished from one another. Experimental results demonstrate the ability of the method to successfully label voxels into one of the above categories and improve the performance of a fibre-tracking algorithm. (c) 2008 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Brain/anatomy & histology Brain/cytology Diffusion Magnetic Resonance Imaging/methods Diffusion Magnetic Resonance Imaging/statistics & numerical data Humans image processing, computer-assisted/methods image processing, computer-assisted/statistics & numerical data Motor Cortex/cytology Motor Cortex/physiology Nerve Fibers/physiology Neural Pathways/anatomy & histology Neural Pathways/cytology Neural Pathways/physiology

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SENSE factors for reliable cortical thickness measurement

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NEUROimage 2008年第1期40卷 187-196页

作者： Park, Hae-Jeong Youn, Tak Jeong, Seok-Oh Oh, Maeng-Keun Kim, Sei-Young Kim, Eung-Yeop Yonsei Univ Coll Med Res Inst Radiol Sci Dept Radiol Seoul 120749 South Korea Yonsei Univ Coll Med Brain Korea 21 Proj Med Sci Seoul South Korea Yonsei Univ Coll Med Dept Nucl Med Seoul South Korea Chonnam Natl Univ Sch Med Dept Psychiat Kwangju South Korea Hankuk Univ Foreign Studies Dept Stat Yongin South Korea

The purposes of this study were to examine the effect of sensitivity encoding (SENSE) factors on cortical thickness measurements and to determine which SENSE factor to use to reliably measure cortical thickness in 3.0 T and 1.5 T T1-weighted MRI images. The 3D T1-TFE images were acquired from 11 healthy volunteers with 6 different SENSE acceleration factors from 1.0 (without SENSE acceleration) to 4.0 on a 1.5 T scanner, and 9 different SENSE factors from 1.0 to 6.0, plus a second-day 1.0 acquisition on a 3.0 T scanner. Cortical thickness was calculated for the entire cortical surface that was further subdivided into 33 regions. Repeated measures multivariate analysis of variance revealed that the main effect of SENSE factors (F= 12.485, df=7, p=0.006) was a significant underestimation of cortical thickness at SENSE 5.0 (p=0.022) and 6.0 (p=0.011) at 3.0 T and at SENSE 4.0 (p < 0.000) at 1.5 T. Repeated measures ANOVA showed that thickness measurements at the insula, superior temporal sulcus, the medial part of the superior frontal lobe, and cingulate cortex are highly affected by SENSE factors. SENSE factors affect thickness estimation more significantly at 1.5 T and thus 1.5 T imaging provides less reliable estimates using SENSE techniques. Faster imaging can be done without too much loss of reliability using a high SENSE factor, such as 3.0, at 3.0 T with acquisition time being inversely proportional to the SENSE factor. (c) 2007 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Analysis of Variance Brain Mapping Brain Mapping Cerebral Cortex/anatomy & histology Cerebral Cortex/physiology Female Humans image processing, computer-assisted/statistics & numerical data Magnetic Resonance Imaging Male Reproducibility of Results

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Quantifying inter-subject agreement in brain-imaging analyses

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NEUROimage 2008年第3期39卷 1051-1063页

作者： Wong, Dik Kin Grosenick, Logan Uy, E. Timothy Guimaraes, Marcos Perreau Carvalhaes, Claudio G. Desain, Peter Suppes, Patrick Stanford Univ Ctr Study Language & Informat Stanford CA 94305 USA Univ Estado Rio de Janeiro Inst Matemat & Estatist Rio De Janeiro Brazil Univ Nijmegen Nijmegen Inst Cognit & Informat Nijmegen Netherlands

In brain-imaging research, we are often interested in making quantitative claims about effects across subjects. Given that most imaging data consist of tens to thousands of spatially correlated time series, inter-subject comparisons are typically accomplished with simple combinations of inter-subject data, for example methods relying on group means. Further, these data are frequently taken from reduced channel subsets defined either a priori using anatomical considerations, or functionally using p-value thresholding to choose cluster boundaries. While such methods are effective for data reduction, means are sensitive to outliers, and current methods for subset selection can be somewhat arbitrary. Here, we introduce a novel "partial-ranking" approach to test for inter-subject agreement at the channel level. This non-parametric method effectively tests whether channel concordance is present across subjects, how many channels are necessary for maximum concordance, and which channels are responsible for this agreement. We validate the method on two previously published and two simulated EEG data sets. (c) 2007 Elsevier Inc. All rights reserved.

关键词： Algorithms Analysis of Variance Brain/anatomy & histology Brain/physiology Brain Mapping Brain Mapping computer Simulation Electroencephalography/statistics & numerical data Humans image processing, computer-assisted/statistics & numerical data Models, Anatomic

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Discriminating brain activity from task-related artifacts in functional MRI: Fractal scaling analysis simulation and application

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NEUROimage 2008年第1期40卷 197-212页

作者： Lee, Jae-Min Hu, Jing Gao, Jianbo Crosson, Bruce Peck, Kyung K. Wierenga, Christina E. McGregor, Keith Zhao, Qun White, Keith D. Univ Florida Dept Psychol Gainesville FL 32611 USA Brain Rehabil Res Ctr Malcolm Randall VAMC Gainesville FL 32608 USA Univ Florida Dept Elect & Comp Engn Gainesville FL 32611 USA Univ Florida Dept Clin & Hlth Psychol Gainesville FL 32611 USA Mem Sloan Kettering Canc Ctr Dept Med Phys New York NY 10021 USA Univ Georgia Dept Phys & Astron Athens GA 30602 USA

Functional magnetic resonance imaging (fMRI) signal changes can be separated from background noise by various processing algorithms, including the well-known deconvolution method. However, discriminating signal changes due to task-related brain activities from those due to task-related head motion or other artifacts correlated in time to the task has been little addressed. We examine whether three exploratory fractal scaling analyses correctly classify these possibilities by capturing temporal self-similarity;namely, fluctuation analysis, wavelet multi-resolution analysis, and detrended fluctuation analysis (DFA). We specifically evaluate whether these fractal analytic methods can be effective and reliable in discriminating activations from artifacts. DFA is indeed robust for such classification. Brain activation maps derived by DFA are similar, but not identical, to maps derived by deconvolution. Deconvolution explicitly utilizes task timing to extract the signals whereas DFA does not, so these methods reveal somewhat different information from the data. DFA is better than deconvolution for distinguishing fMRI activations from task-related artifacts, although a combination of these approaches is superior to either one taken alone. We also present a method for estimating noise levels in fMRI data, validated with numerical simulations suggesting that Birn's model is effective for simulating fMRI signals. Simulations further corroborate that DFA is excellent at discriminating signal changes due to task-related brain activities from those due to task-related artifacts, under a range of conditions. (c) 2007 Elsevier Inc. All rights reserved.

关键词： Adult Aged Algorithms Artifacts Brain/physiology Cerebrovascular Circulation/physiology computer Simulation Female Fingers/physiology Fractals Humans image processing, computer-assisted/statistics & numerical data Magnetic Resonance Imaging/methods Magnetic Resonance Imaging/statistics & numerical data Male Movement/physiology Psychomotor Performance/physiology Pyramidal Tracts/anatomy & histology Pyramidal Tracts/physiology ROC Curve Software

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Composite voxel-based analysis of volume and T2 relaxometry in temporal lobe epilepsy

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NEUROimage 2008年第3期39卷 1151-1161页

作者： Pell, Gaby S. Briellmann, Regula S. Pardoe, Heath Abbott, David F. Jackson, Graeme D. Brain Res Inst Heidelberg Vic 3081 Australia Univ Melbourne Dept Med Neurol Parkville Vic 3052 Australia

Voxel-based analyses of tissue characteristics such as volume and T2 are usually carried out in isolation. However, as the images are analysed in a common voxel-based framework, it is possible to directly assess the spatial relationships of abnormalities detected by each technique. We utilize this approach in well-characterized patients with unilateral temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS). TLE is associated with potentially widespread volume and T2 signal abnormalities in MRI images but the relationship between these two aspects of tissue abnormality is not well understood. Here we use a novel approach of combined univariate and multivariate voxel-wise analysis to investigate the spatial relationship of these abnormalities. We studied 19 TLE patients and compared them to 115 control subjects. Grey matter (GM) and white matter (WM) volume changes were assessed with voxel-based morphometry (VBM), and changes in T2 relaxation times were evaluated with voxel-based relaxometry (VBR). The volume and T2 changes obtained using the combined univariate approach were found in an extensive area, prominently in the ipsilateral hippocampus and amygdala (overlap of GM-VBM and VBR), and in the remaining temporal lobe (overlap of WM-VBR and VBR). Other cortical and subcortical areas showed isolated volume or T2 changes. The multivariate analysis based on the Hotelling T-2 statistic, indicated a similar pattern of distributed changes across the brain but with a greater degree of statistical significance in certain areas. The composite analyses appear to identify a network of affected areas not as easily appreciated by the individual analysis of volume or T2 changes. (c) 2007 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Analysis of Variance Epilepsy, Temporal Lobe/pathology Female Hippocampus/pathology Humans image processing, computer-assisted/statistics & numerical data Magnetic Resonance Imaging/statistics & numerical data Male Sclerosis

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Functional localization in the human cerebellum based on voxelwise statistical analysis: A study of 90 patients

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NEUROimage 2006年第1期30卷 36-51页

作者： Schoch, B Dimitrova, A Gizewski, ER Timmann, D Univ Duisburg Essen Dept Neurosurg D-45122 Essen Germany Univ Duisburg Essen Dept Neurol D-45122 Essen Germany Univ Duisburg Essen Dept Neuroradiol D-45122 Essen Germany

The aim of the present study was to examine somatotopy in the cerebellar cortex and a possible differential role of the cerebellar cortex and nuclei in functional outcome. Clinical findings and 3D MRI-based cerebellar lesions site were compared in a group of 90 patients with focal cerebellar lesion using International Cooperative Ataxia Rating Scale (ICARS) and voxel-based lesion-symptom mapping (VLSM). Separate analysis was performed in patients with acute and chronic ischemic lesions (n = 43) and patients with acute and chronic surgical lesions (n = 47). Thirty-eight patients were included after resection of a cerebellar tumor in childhood or adolescence. The most significant lesion symptom correlations were observed in the subgroup with acute ischemic lesions. Limb ataxia was significantly correlated with lesions of the interposed (NI) and part of the dentate nuclei (ND), ataxia of posture and gait with lesions of the fastigial nuclei (NF) including NI. Correlations with cortical lesions were less significant and present in the superior cerebellum only. Upper limb ataxia was correlated with lesions of vermal, paravermal and hemispheral lobules IV-V and VI, lower limb ataxia with lesions of vermal, paravermal and hemispheral lobules III and VI, dysarthria with lesions of paravermal and hemispheral lobules V and VI and ataxia of posture and gait with lesions of vermal and paravermal lobules II, III and IV. In the subgroups with chronic focal lesions, similar correlations were observed with lesions of the cerebellar nuclei, but significantly less correlations with lesions of the cerebellar cortex. Functional localization based on VLSM backs findings in previous animal and functional brain images studies in healthy human subjects. The lesion site appears to be critical for motor recovery. Lesions affecting the cerebellar nuclei are not fully compensated at any age and independent of the pathology in humans. (c) 2005 Elsevier Inc. All rights reserved.

关键词： Adult Aged Brain Damage, Chronic/etiology Brain Damage, Chronic/physiopathology Brain Mapping Brain Mapping Cerebellar Cortex/physiopathology Cerebellar Diseases/etiology Cerebellar Diseases/physiopathology Cerebellar Nuclei/physiopathology Female Humans image processing, computer-assisted/statistics & numerical data Imaging, Three-Dimensional Magnetic Resonance Imaging/statistics & numerical data Male Mathematical Computing Middle Aged Neurologic Examination/statistics & numerical data Recovery of Function

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Non-normality and transformation of random fields, with an application to voxel-based morphometry

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NEUROimage 2007年第1期35卷 121-130页

作者： Viviani, Roberto Beschoner, Petra Ehrhard, Katja Schmitz, Bemd Thoene, Jan Univ Ulm Dept Psychiat 3 D-89075 Ulm Germany Univ Ulm Dept Radiol D-89075 Ulm Germany Univ Ulm Transfer Ctr Neurosci & Learning ZNL D-89075 Ulm Germany

Parametric tests of linear models for images modeled as random fields are based like ordinary univariate tests on distributional assumptions. It is here shown that the effect of departures from assumptions in random field tests is more pronounced than in the univariate condition. Simulations are presented investigating in detail the influence of smoothing, unbalancedness and leverages on empirical thresholds. In certain conditions, significance tests may become invalid. As a case study, the existence and effect of departures from normality of gray matter probability maps, commonly used in voxel-based morphometry, is investigated, as well as the effect of different transformation strategies involving estimating the degree of transformation from the data by maximum likelihood. The best results are achieved with a voxel-by-voxel transformation, suggesting heterogeneity of distributional form across the volume for this kind of data. (c) 2006 Elsevier Inc. All rights reserved.

关键词： Adult Algorithms Analysis of Variance Artifacts Brain Mapping Brain Mapping computer Simulation Humans image processing, computer-assisted/statistics & numerical data Linear Models Magnetic Resonance Imaging/statistics & numerical data Models, Statistical Monte Carlo Method Reference Values Regression Analysis

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Reproducibility and reliability of MR measurements in white matter: Clinical implications

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NEUROimage 2006年第2期32卷 637-642页

作者： Vavasour, Irene M. Clark, Campbell M. Li, David K. B. MacKay, Alex L. Univ British Columbia Dept Radiol Vancouver BC V6T 2B5 Canada Univ British Columbia Dept Psychiat Vancouver BC V6T 2B5 Canada Univ British Columbia Dept Phys & Astron Vancouver BC V6T 2B5 Canada

The purpose of this study was to determine the reproducibility and reliability of five MRI-derived measurements, namely, total water content (WC), myelin water content (MWC), mean T-2 relaxation time (GMT(2)), T-1 relaxation time (T-1) and magnetization transfer ratio (MTR). Five controls were scanned 5 times over 1 year. The five MR measurements were made for 5 white matter regions. All measurements were found to be highly reproducible. MTR bad a low reliability coefficient because all individual values were similar. Therefore, MTR would be most sensitive in detecting changes from normal. WC had a high reliability coefficient in all regions. For MWC, GMT(2) and T-1, the overall reliability coefficients were high but for some individual regions were low. The high coefficients suggest that these measurements, although different between normal subjects, are consistent over time. They could be used to explore natural differences in the normal population, but due to the large spread in normal values, larger sample sizes are needed to detect pathological changes. (c) 2006 Elsevier Inc. All rights reserved.

关键词： Adult Corpus Callosum/anatomy & histology Female Follow-Up Studies Humans image processing, computer-assisted/statistics & numerical data Internal Capsule/anatomy & histology Magnetic Resonance Imaging/statistics & numerical data Male Mathematical Computing Middle Aged Myelin Sheath/metabolism Reproducibility of Results

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