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Sample records for brain magnetic resolution

  1. Transcranial magnetic stimulation of mouse brain using high-resolution anatomical models

    Science.gov (United States)

    Crowther, L. J.; Hadimani, R. L.; Kanthasamy, A. G.; Jiles, D. C.

    2014-05-01

    Transcranial magnetic stimulation (TMS) offers the possibility of non-invasive treatment of brain disorders in humans. Studies on animals can allow rapid progress of the research including exploring a variety of different treatment conditions. Numerical calculations using animal models are needed to help design suitable TMS coils for use in animal experiments, in particular, to estimate the electric field induced in animal brains. In this paper, we have implemented a high-resolution anatomical MRI-derived mouse model consisting of 50 tissue types to accurately calculate induced electric field in the mouse brain. Magnetic field measurements have been performed on the surface of the coil and compared with the calculations in order to validate the calculated magnetic and induced electric fields in the brain. Results show how the induced electric field is distributed in a mouse brain and allow investigation of how this could be improved for TMS studies using mice. The findings have important implications in further preclinical development of TMS for treatment of human diseases.

  2. High-Resolution Magnetic Resonance Angiography of the Mouse Brain: Application to Murine Focal Cerebral Ischemia Models

    Science.gov (United States)

    Beckmann, Nicolau; Stirnimann, Roger; Bochelen, Damien

    1999-10-01

    Three-dimensional time-of-flight high-resolution magnetic resonance angiography was applied to visualize the cerebral vasculature of the mouse brain. In normal mice, angiograms of good quality, showing the essential details of the arterial cerebrovascular anatomy, could be obtained in only 2.5 min without the use of contrast agents. Signals from slowly flowing blood, e.g., in veins, could also be detected after administration of a blood pool contrast agent. The technique was applied to mouse models of permanent and transient brain ischemia, involving the occlusion of the middle cerebral artery. High-resolution magnetic resonance angiography proved to be a very useful tool for verifying the success of the occlusion in these models.

  3. Sub-millimeter resolution electrical conductivity images of brain tissues using magnetic resonance-based electrical impedance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Tong In; Jeong, Woo Chul; Sajib, Saurav Z. K.; Kim, Hyung Joong, E-mail: bmekim@khu.ac.kr; Woo, Eung Je [Department of Biomedical Engineering, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kim, Hyun Bum [Department of East-West Medical Science, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kyung, Eun Jung [Department of Pharmacology, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Kwon, Oh In [Department of Mathematics, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2015-07-13

    Recent magnetic resonance (MR)-based electrical impedance tomography (MREIT) of in vivo animal and human subjects enabled the imaging of electromagnetic properties, such as conductivity and permittivity, on tissue structure and function with a few millimeter pixel size. At those resolutions, the conductivity contrast might be sufficient to distinguish different tissue type for certain applications. Since the precise measurement of electrical conductivity under the tissue levels can provide alternative information in a wide range of biomedical applications, it is necessary to develop high-resolution MREIT technique to enhance its availability. In this study, we provide the experimental evaluation of sub-millimeter resolution conductivity imaging method using a 3T MR scanner combined with a multi-echo MR pulse sequence, multi-channel RF coil, and phase optimization method. From the phantom and animal imaging results, sub-millimeter resolution exhibited similar signal-to-noise ratio of MR magnitude and noise levels in magnetic flux density comparing to the existing millimeter resolution. The reconstructed conductivity images at sub-millimeter resolution can distinguish different brain tissues with a pixel size as small as 350 μm.

  4. Sub-millimeter resolution electrical conductivity images of brain tissues using magnetic resonance-based electrical impedance tomography

    International Nuclear Information System (INIS)

    Recent magnetic resonance (MR)-based electrical impedance tomography (MREIT) of in vivo animal and human subjects enabled the imaging of electromagnetic properties, such as conductivity and permittivity, on tissue structure and function with a few millimeter pixel size. At those resolutions, the conductivity contrast might be sufficient to distinguish different tissue type for certain applications. Since the precise measurement of electrical conductivity under the tissue levels can provide alternative information in a wide range of biomedical applications, it is necessary to develop high-resolution MREIT technique to enhance its availability. In this study, we provide the experimental evaluation of sub-millimeter resolution conductivity imaging method using a 3T MR scanner combined with a multi-echo MR pulse sequence, multi-channel RF coil, and phase optimization method. From the phantom and animal imaging results, sub-millimeter resolution exhibited similar signal-to-noise ratio of MR magnitude and noise levels in magnetic flux density comparing to the existing millimeter resolution. The reconstructed conductivity images at sub-millimeter resolution can distinguish different brain tissues with a pixel size as small as 350 μm

  5. High-Resolution Longitudinal Screening with Magnetic Resonance Imaging in a Murine Brain Cancer Model

    Directory of Open Access Journals (Sweden)

    Nicholas A. Bock

    2003-11-01

    Full Text Available One of the main limitations of intracranial models of diseases is our present inability to monitor and evaluate the intracranial compartment noninvasively over time. Therefore, there is a growing need for imaging modalities that provide thorough neuropathological evaluations of xenograft and transgenic models of intracranial pathology. In this study, we have established protocols for multiple-mouse magnetic resonance imaging (MRI to follow the growth and behavior of intracranial xenografts of gliomas longitudinally. We successfully obtained weekly images on 16 mice for a total of 5 weeks on a 7-T multiple-mouse MRI. T2- and Ti-weighted imaging with gadolinium enhancement of vascularity was used to detect tumor margins, tumor size, and growth. These experiments, using 3D whole brain images obtained in four mice at once, demonstrate the feasibility of obtaining repeat radiological images in intracranial tumor models and suggest that MRI should be incorporated as a research modality for the investigation of intracranial pathobiology.

  6. Echo-planar magnetic resonance imaging (EPI) with high-resolution matrix in intra-axial brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Bruening, R.; Scheidler, J.; Porn, U.; Reiser, M. [Institute of Diagnostic Radiology, Klinikum Grosshadern, University of Munich (Germany); Seelos, K.; Yousry, T. [Department of Neuroradiology, Institute of Diagnostic Radiology, Klinikum Grosshadern, University of Munich (Germany); Exner, H. [Institute for Medical Epidemiology, Klinikum Grosshadern, University of Munich, Munich (Germany); Rosen, B.R. [Department of Radiology, Massachusetts General Hospital, NMR Center, Charlestown, MA (United States)

    1999-09-01

    The aim of this study was to assess the potential of high-speed interleaved echo-planar imaging (EPI) to achieve diagnostic image quality comparable to T2-weighted imaging in patients with brain tumors. Seventeen patients with intra-axial, supratentorial tumors (10 untreated gliomas, 7 radiated gliomas) were investigated on a 1.5-T scanner. The conventional scan (SE, TR/TE = 2200/80 ms, 18 slices) was acquired in 8 min, 4 s, and EPI (TR/TE = 3000/80 ms, 18 slices) was completed in 25 s. The films were compared in a blinded trail by three radiologists. On the general impression and anatomic display, both sequences were rated to be of similar quality. Artifacts were slightly more pronounced at the skull base and around surgical clips using EPI. Tumor delineation was nearly equivalent using EPI, compared with the T2-weighted sequence. Echo-planar imaging reached diagnostic quality in all patients. Interleaved high-resolution EPI yielded sufficient quality to depict intra-axial, supratentorial brain tumors. Since EPI can be obtained in a small fraction of the time needed for conventional spin echo, in addition to other indications it could be considered to study patients unable to cooperate. (orig.) With 3 figs., 3 tabs., 27 refs.

  7. Echo-planar magnetic resonance imaging (EPI) with high-resolution matrix in intra-axial brain tumors

    International Nuclear Information System (INIS)

    The aim of this study was to assess the potential of high-speed interleaved echo-planar imaging (EPI) to achieve diagnostic image quality comparable to T2-weighted imaging in patients with brain tumors. Seventeen patients with intra-axial, supratentorial tumors (10 untreated gliomas, 7 radiated gliomas) were investigated on a 1.5-T scanner. The conventional scan (SE, TR/TE = 2200/80 ms, 18 slices) was acquired in 8 min, 4 s, and EPI (TR/TE = 3000/80 ms, 18 slices) was completed in 25 s. The films were compared in a blinded trail by three radiologists. On the general impression and anatomic display, both sequences were rated to be of similar quality. Artifacts were slightly more pronounced at the skull base and around surgical clips using EPI. Tumor delineation was nearly equivalent using EPI, compared with the T2-weighted sequence. Echo-planar imaging reached diagnostic quality in all patients. Interleaved high-resolution EPI yielded sufficient quality to depict intra-axial, supratentorial brain tumors. Since EPI can be obtained in a small fraction of the time needed for conventional spin echo, in addition to other indications it could be considered to study patients unable to cooperate. (orig.)

  8. Post-mortem magnetic resonance microscopy (MRM of the murine brain at 7 Tesla results in a gain of resolution as compared to in-vivo MRM

    Directory of Open Access Journals (Sweden)

    Oliver evon Bohlen und Halbach

    2014-06-01

    Full Text Available Small animal MRI with high field strength allows imaging of the living animal. However, spatial resolution in in-vivo brain imaging is limited by the scanning time. Measurements of fixated mouse brains allow longer measurement time, but fixation procedures are time consuming, since the process of fixation may take several weeks. We here present a quick and simple post-mortem approach without fixation that allows high-resolution MRI even at 7 Tesla (T2-weighted MRI. This method was compared to in-vivo scans with optimized spatial resolution for the investigation of anaesthetized mice (T1-weighted MRI as well as to ex-situ scans of fixed brains (T1- and T2-weighted scans by using standard MRI-sequences, along with anatomic descriptions of areas observable in the MRI, analysis of tissue shrinkage and post-processing procedures (intensity inhomogeneity correction, PCNN3D brain extract, SPMMouse segmentation and volumetric measurement. Post-mortem imaging quality was sufficient to determine small brain substructures on the morphological level, provided fast possibilities for volumetric acquisition and for automatized processing without manual correction. Moreover, since no fixation was used, tissue shrinkage due to fixation does not occur as it is, e.g., the case by using ex-vivo brains that have been kept in fixatives for several days. Thus, the introduced method is well-suited for comparative investigations, since it allows determining small structural alterations in the murine brain at a reasonable high resolution even by MRI performed at 7 Tesla.

  9. Nuclear magnetic resonance imaging at microscopic resolution

    Science.gov (United States)

    Johnson, G. Allan; Thompson, Morrow B.; Gewalt, Sally L.; Hayes, Cecil E.

    Resolution limits in NMR imaging are imposed by bandwidth considerations, available magnetic gradients for spatial encoding, and signal to noise. This work reports modification of a clinical NMR imaging device with picture elements of 500 × 500 × 5000 μm to yield picture elements of 50 × 50 × 1000 μm. Resolution has been increased by using smaller gradient coils permitting gradient fields >0.4 mT/cm. Significant improvements in signal to noise are achieved with smaller rf coils, close attention to choice of bandwidth, and signal averaging. These improvements permit visualization of anatomical structures in the rat brain with an effective diameter of 1 cm with the same definition as is seen in human imaging. The techniques and instrumentation should open a number of basic sciences such as embryology, plant sciences, and teratology to the potentials of NMR imaging.

  10. Comprehensive cellular-resolution atlas of the adult human brain.

    Science.gov (United States)

    Ding, Song-Lin; Royall, Joshua J; Sunkin, Susan M; Ng, Lydia; Facer, Benjamin A C; Lesnar, Phil; Guillozet-Bongaarts, Angie; McMurray, Bergen; Szafer, Aaron; Dolbeare, Tim A; Stevens, Allison; Tirrell, Lee; Benner, Thomas; Caldejon, Shiella; Dalley, Rachel A; Dee, Nick; Lau, Christopher; Nyhus, Julie; Reding, Melissa; Riley, Zackery L; Sandman, David; Shen, Elaine; van der Kouwe, Andre; Varjabedian, Ani; Write, Michelle; Zollei, Lilla; Dang, Chinh; Knowles, James A; Koch, Christof; Phillips, John W; Sestan, Nenad; Wohnoutka, Paul; Zielke, H Ronald; Hohmann, John G; Jones, Allan R; Bernard, Amy; Hawrylycz, Michael J; Hof, Patrick R; Fischl, Bruce; Lein, Ed S

    2016-11-01

    Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole-brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high-resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and 1,356 large-format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto- and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127-3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.

  11. Magnetic measurements with atomic-plane resolution

    Science.gov (United States)

    Rusz, Ján; Muto, Shunsuke; Spiegelberg, Jakob; Adam, Roman; Tatsumi, Kazuyoshi; Bürgler, Daniel E.; Oppeneer, Peter M.; Schneider, Claus M.

    2016-01-01

    Rapid development of magnetic nanotechnologies calls for experimental techniques capable of providing magnetic information with subnanometre spatial resolution. Available probes of magnetism either detect only surface properties, such as spin-polarized scanning tunnelling microscopy, magnetic force microscopy or spin-polarized low-energy electron microscopy, or they are bulk probes with limited spatial resolution or quantitativeness, such as X-ray magnetic circular dichroism or classical electron magnetic circular dichroism (EMCD). Atomic resolution EMCD methods have been proposed, although not yet experimentally realized. Here, we demonstrate an EMCD technique with an atomic size electron probe utilizing a probe-corrected scanning transmission electron microscope in its standard operation mode. The crucial element of the method is a ramp in the phase of the electron beam wavefunction, introduced by a controlled beam displacement. We detect EMCD signals with atomic-plane resolution, thereby bringing near-atomic resolution magnetic circular dichroism spectroscopy to hundreds of laboratories worldwide. PMID:27578421

  12. Magnetic measurements with atomic-plane resolution.

    Science.gov (United States)

    Rusz, Ján; Muto, Shunsuke; Spiegelberg, Jakob; Adam, Roman; Tatsumi, Kazuyoshi; Bürgler, Daniel E; Oppeneer, Peter M; Schneider, Claus M

    2016-01-01

    Rapid development of magnetic nanotechnologies calls for experimental techniques capable of providing magnetic information with subnanometre spatial resolution. Available probes of magnetism either detect only surface properties, such as spin-polarized scanning tunnelling microscopy, magnetic force microscopy or spin-polarized low-energy electron microscopy, or they are bulk probes with limited spatial resolution or quantitativeness, such as X-ray magnetic circular dichroism or classical electron magnetic circular dichroism (EMCD). Atomic resolution EMCD methods have been proposed, although not yet experimentally realized. Here, we demonstrate an EMCD technique with an atomic size electron probe utilizing a probe-corrected scanning transmission electron microscope in its standard operation mode. The crucial element of the method is a ramp in the phase of the electron beam wavefunction, introduced by a controlled beam displacement. We detect EMCD signals with atomic-plane resolution, thereby bringing near-atomic resolution magnetic circular dichroism spectroscopy to hundreds of laboratories worldwide. PMID:27578421

  13. Magnetic Resonance Lithography with Nanometer Resolution

    Directory of Open Access Journals (Sweden)

    Fahad AlGhannam

    2016-04-01

    Full Text Available We propose an approach for super-resolution optical lithography which is based on the inverse of magnetic resonance imaging (MRI. The technique uses atomic coherence in an ensemble of spin systems whose final state population can be optically detected. In principle, our method is capable of producing arbitrary one and two dimensional high-resolution patterns with high contrast.

  14. Design of modern high resolution magnetic spectrometers

    International Nuclear Information System (INIS)

    The choice of correcting nonlinear aberrations in high resolution magnetic spectrometers with software or hardware is examined. The ability of raytracing methods, using realistic focal plane detector resolutions, is demonstrated for the S800 spectrograph under construction at the National Superconducting Cyclotron Laboratory (NSCL). Furthermore, Differential Algebraic methods are shown to reproduce the results for accurately known fields at a considerable savings in design time. (Author)

  15. Magnetic resonance imaging safety of deep brain stimulator devices.

    Science.gov (United States)

    Oluigbo, Chima O; Rezai, Ali R

    2013-01-01

    Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices. PMID:24112886

  16. Magnetic resonance imaging safety of deep brain stimulator devices.

    Science.gov (United States)

    Oluigbo, Chima O; Rezai, Ali R

    2013-01-01

    Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices.

  17. Nonparametric Bayesian Clustering of Structural Whole Brain Connectivity in Full Image Resolution

    DEFF Research Database (Denmark)

    Ambrosen, Karen Marie Sandø; Albers, Kristoffer Jon; Dyrby, Tim B.;

    2014-01-01

    groups) that defines structural units at the resolution of statistical support. We apply the model to a network of structural brain connectivity in full image resolution with more than one hundred thousand regions (voxels in the gray-white matter boundary) and around one hundred million connections......Diffusion magnetic resonance imaging enables measuring the structural connectivity of the human brain at a high spatial resolution. Local noisy connectivity estimates can be derived using tractography approaches and statistical models are necessary to quantify the brain’s salient structural....... The derived clustering identifies in the order of one thousand salient structural units and we find that the identified units provide better predictive performance than predicting using the full graph or two commonly used atlases. Extracting structural units of brain connectivity at the full image resolution...

  18. Exploring brain function with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology

  19. High resolution magnetic spectrograph 'Grand Raiden'

    International Nuclear Information System (INIS)

    In the report of the last 1988, the basic design of a new high resolution (p/Δp = 37750) magnetic spectrograph of the type QSQDMD (+D), named 'Grand Raiden', was presented. Here, we show results of more detailed ray-tracing calculations; the focal line property, the image aberration, and the compensation of the kinematic broadening by multipole fields. The final design of the new DSR (dipole for spin rotation) for the measurement of in-plane spin observables are also reported. (author)

  20. Magnetic resonance imaging of brain death

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.H.; Nathanson, J.A.; Fox, A.J.; Pelz, D.M.; Lownie, S.P.

    1995-06-01

    In order to demonstrate the magnetic resonance imaging (MRI) appearance of the brain in patients with clinical brain death, high-field MRI was performed on 5 patients using conventional T1-weighted and T2-weighted imaging. The study showed MRI exhibited similar features for all of the patients, features which were not found in MRI of comatose patients who were not clinically brain dead. It was stated that up to now the most important limitation in MRI of patients with suspected brain death has been the extreme difficulty of moving them out of the intensive care setting. If this problem can be overcome, and it appears possible with with the advent of MRI-compatible ventilators and noninvasive monitoring, MRI could become an excellent alternative for confirming clinical diagnosis of brain death for such patients. 15 refs., 3 figs.

  1. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    Science.gov (United States)

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  2. Separate effects of sex hormones and sex chromosomes on brain structure and function revealed by high-resolution magnetic resonance imaging and spatial navigation assessment of the Four Core Genotype mouse model.

    Science.gov (United States)

    Corre, Christina; Friedel, Miriam; Vousden, Dulcie A; Metcalf, Ariane; Spring, Shoshana; Qiu, Lily R; Lerch, Jason P; Palmert, Mark R

    2016-03-01

    Males and females exhibit several differences in brain structure and function. To examine the basis for these sex differences, we investigated the influences of sex hormones and sex chromosomes on brain structure and function in mice. We used the Four Core Genotype (4CG) mice, which can generate both male and female mice with XX or XY sex chromosome complement, allowing the decoupling of sex chromosomes from hormonal milieu. To examine whole brain structure, high-resolution ex vivo MRI was performed, and to assess differences in cognitive function, mice were trained on a radial arm maze. Voxel-wise and volumetric analyses of MRI data uncovered a striking independence of hormonal versus chromosomal influences in 30 sexually dimorphic brain regions. For example, the bed nucleus of the stria terminalis and the parieto-temporal lobe of the cerebral cortex displayed steroid-dependence while the cerebellar cortex, corpus callosum, and olfactory bulbs were influenced by sex chromosomes. Spatial learning and memory demonstrated strict hormone-dependency with no apparent influence of sex chromosomes. Understanding the influences of chromosomes and hormones on brain structure and function is important for understanding sex differences in brain structure and function, an endeavor that has eventual implications for understanding sex biases observed in the prevalence of psychiatric disorders.

  3. In Vivo Brain MR Imaging at Subnanoliter Resolution: Contrast and Histology.

    Science.gov (United States)

    Watanabe, Takashi; Frahm, Jens; Michaelis, Thomas

    2016-01-01

    This article provides an overview of in vivo magnetic resonance (MR) imaging contrasts obtained for mammalian brain in relation to histological knowledge. Emphasis is paid to the (1) significance of high spatial resolution for the optimization of T1, T2, and magnetization transfer contrast, (2) use of exogenous extra- and intracellular contrast agents for validating endogenous contrast sources, and (3) histological structures and biochemical compounds underlying these contrasts and (4) their relevance to neuroradiology. Comparisons between MR imaging at subnanoliter resolution and histological data indicate that (a) myelin sheaths, (b) nerve cells, and (c) the neuropil are most responsible for observed MR imaging contrasts, while (a) diamagnetic macromolecules, (b) intracellular paramagnetic ions, and (c) extracellular free water, respectively, emerge as the dominant factors. Enhanced relaxation rates due to paramagnetic ions, such as iron and manganese, have been observed for oligodendrocytes, astrocytes, microglia, and blood cells in the brain as well as for nerve cells. Taken together, a plethora of observations suggests that the delineation of specific structures in high-resolution MR imaging of mammalian brain and the absence of corresponding contrasts in MR imaging of the human brain do not necessarily indicate differences between species but may be explained by partial volume effects. Second, paramagnetic ions are required in active cells in vivo which may reduce the magnetization transfer ratio in the brain through accelerated T1 recovery. Third, reductions of the magnetization transfer ratio may be more sensitive to a particular pathological condition, such as astrocytosis, microglial activation, inflammation, and demyelination, than changes in relaxation. This is because the simultaneous occurrence of increased paramagnetic ions (i.e., shorter relaxation times) and increased free water (i.e., longer relaxation times) may cancel T1 or T2 effects, whereas

  4. Nonparametric Bayesian Clustering of Structural Whole Brain Connectivity in Full Image Resolution

    DEFF Research Database (Denmark)

    Ambrosen, Karen Marie Sandø; Albers, Kristoffer Jon; Dyrby, Tim B.;

    2014-01-01

    Diffusion magnetic resonance imaging enables measuring the structural connectivity of the human brain at a high spatial resolution. Local noisy connectivity estimates can be derived using tractography approaches and statistical models are necessary to quantify the brain’s salient structural organ...... can aid in understanding the underlying connectivity patterns, and the proposed method for large scale data driven generation of structural units provides a promising framework that can exploit the increasing spatial resolution of neuro-imaging technologies.......Diffusion magnetic resonance imaging enables measuring the structural connectivity of the human brain at a high spatial resolution. Local noisy connectivity estimates can be derived using tractography approaches and statistical models are necessary to quantify the brain’s salient structural...... groups) that defines structural units at the resolution of statistical support. We apply the model to a network of structural brain connectivity in full image resolution with more than one hundred thousand regions (voxels in the gray-white matter boundary) and around one hundred million connections. The...

  5. Targeted drug delivery to the brain using magnetic nanoparticles.

    Science.gov (United States)

    Thomsen, Louiza Bohn; Thomsen, Maj Schneider; Moos, Torben

    2015-01-01

    Brain capillary endothelial cells denote the blood-brain barrier (BBB), and conjugation of nanoparticles with antibodies that target molecules expressed by these endothelial cells may facilitate their uptake and transport into the brain. Magnetic nanoparticles can be encapsulated in liposomes and carry large molecules with therapeutic potential, for example, siRNA, cDNA and polypeptides. An additional approach to enhance the transport of magnetic nanoparticles across the BBB is the application of extracranially applied magnetic force. Stepwise targeting of magnetic nanoparticles to brain capillary endothelial cells followed by transport through the BBB using magnetic force may prove a novel mechanism for targeted therapy of macromolecules to the brain.

  6. Sparse Bayesian framework applied to 3D super-resolution reconstruction in fetal brain MRI

    Science.gov (United States)

    Becerra, Laura C.; Velasco Toledo, Nelson; Romero Castro, Eduardo

    2015-01-01

    Fetal Magnetic Resonance (FMR) is an imaging technique that is becoming increasingly important as allows assessing brain development and thus make an early diagnostic of congenital abnormalities, spatial resolution is limited by the short acquisition time and the unpredictable fetus movements, in consequence the resulting images are characterized by non-parallel projection planes composed by anisotropic voxels. The sparse Bayesian representation is a flexible strategy which is able to model complex relationships. The Super-resolution is approached as a regression problem, the main advantage is the capability to learn data relations from observations. Quantitative performance evaluation was carried out using synthetic images, the proposed method demonstrates a better reconstruction quality compared with standard interpolation approach. The presented method is a promising approach to improve the information quality related with the 3-D fetal brain structure. It is important because allows assessing brain development and thus make an early diagnostic of congenital abnormalities.

  7. Nuclear magnetic resonance imaging in brain tumors

    International Nuclear Information System (INIS)

    Full text: Magnetic resonance imaging (MRI) is a non-invasive imaging method based on the detecting signal from hydrogen nuclei of water molecules and fat. Performances of MRI are continuously increasing, and its domains of investigation of the human body are growing in both morphological and functional study. MRI also allows It also performing advanced management of tumours especially in the brain, by combining anatomical information (morphological MRI), functional (diffusion, perfusion and BOLD contrast) and metabolic (tissue composition in magnetic resonance spectroscopy (MRS)). The MRI techniques have an important role in cancerology. These techniques allow essential information for the diagnosis and answering therapist's questions before, during or after the treatment. The MR allows clarifying the localization of expanding processes, the differential diagnosis between brain tumour and a lesion confined by another structural aspect, the diagnosis of the tumoral aspect of a lesion, the histological ranking in case of glial tumour and the extension of its localization as well as the therapeutic follow-up (pre-therapeutic and post-therapeutics assessments). A better combination between the morphological, functional and metabolic studies, as well as integrating new technical developments, especially while using a multichannel bird cage coils the 3T magnet and suitable computing software, would allow significant improvements of the exploration strategies and management of brain tumors.

  8. Compact and mobile high resolution PET brain imager

    Science.gov (United States)

    Majewski, Stanislaw; Proffitt, James

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  9. Developments in magnets for the high resolution RCNP spectrograph

    International Nuclear Information System (INIS)

    A summary is given for the developments of magnets employed in the high resolution spectrometer now in operation at RCNP. Special care was taken to obtain high uniformities in the magnetic field distributions. A new method for constructing a magnet with a high field uniformity as well as a good reproducibility at a reasonable cost is described. (author)

  10. Magnetic resonance imaging of a brain abscess

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess. (author)

  11. Magnetic resonance imaging of a brain abscess

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, Akihiro; Kagawa, Mizuo; Yatoh, Seiji; Izawa, Masahiro; Ujiie, Hiroshi; Sakaguchi, Jun; Onda, Hideaki; Kitamura, Kohichi

    1988-06-01

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess.

  12. Impact of the resolution of brain parcels on connectome-wide association studies in fMRI.

    Science.gov (United States)

    Bellec, Pierre; Benhajali, Yassine; Carbonell, Felix; Dansereau, Christian; Albouy, Geneviève; Pelland, Maxime; Craddock, Cameron; Collignon, Oliver; Doyon, Julien; Stip, Emmanuel; Orban, Pierre

    2015-12-01

    A recent trend in functional magnetic resonance imaging is to test for association of clinical disorders with every possible connection between selected brain parcels. We investigated the impact of the resolution of functional brain parcels, ranging from large-scale networks to local regions, on a mass univariate general linear model (GLM) of connectomes. For each resolution taken independently, the Benjamini-Hochberg procedure controlled the false-discovery rate (FDR) at nominal level on realistic simulations. However, the FDR for tests pooled across all resolutions could be inflated compared to the FDR within resolution. This inflation was severe in the presence of no or weak effects, but became negligible for strong effects. We thus developed an omnibus test to establish the overall presence of true discoveries across all resolutions. Although not a guarantee to control the FDR across resolutions, the omnibus test may be used for descriptive analysis of the impact of resolution on a GLM analysis, in complement to a primary analysis at a predefined single resolution. On three real datasets with significant omnibus test (schizophrenia, congenital blindness, motor practice), markedly higher rate of discovery were obtained at low resolutions, below 50, in line with simulations showing increase in sensitivity at such resolutions. This increase in discovery rate came at the cost of a lower ability to localize effects, as low resolution parcels merged many different brain regions together. However, with 30 or more parcels, the statistical effect maps were biologically plausible and very consistent across resolutions. These results show that resolution is a key parameter for GLM-connectome analysis with FDR control, and that a functional brain parcellation with 30 to 50 parcels may lead to an accurate summary of full connectome effects with good sensitivity in many situations.

  13. Recent development in noninvasive brain activity measurement by functional magnetic resonance imaging (fMRI)

    International Nuclear Information System (INIS)

    fMRI (functional magnetic resonance imaging) is a non-invasive brain imaging technique with which the distribution of neural activity is estimated by measuring local blood flow changes. Blood-oxygenation-level-dependent (BOLD) method measures changes in the density of deoxidized hemoglobin in blood caused by blood flow changes, while other methods have been developed to measure the blood flow changes directly. Effort has been expended to realize a submillimeter spatial resolution by using higher static magnetic field. fMRI has been carried out with various mental tasks, and many important findings have been made on the localization of higher brain functions. (author)

  14. Fetal magnetic resonance imaging of the brain: technical considerations and normal brain development

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, Thierry A.G.M.; Kubik-Huch, Rahel; Marincek, Borut [Institute of Diagnostic Radiology, University Hospital Zurich, 8091 Zurich (Switzerland); Martin, Ernst [Department of Neuroradiology and Magnetic Resonance, University Children' s Hospital, 8091 Zurich (Switzerland)

    2002-08-01

    Fetal MRI examines non-invasively the unborn fetus. Ultrafast MRI sequences effectively suppress fetal motion. Multiple case reports and studies have shown that fetal MRI is particularly helpful in the evaluation of the central nervous system. The high contrast-to-noise ratio, the high spatial resolution, the multiplanar capabilities, the large field of view and the simultaneous visualisation of fetal and maternal structures have proven to be advantageous. Fetal MRI is particularly helpful in the evaluation of the normal and pathological development of the brain. Despite the fact that no side effects have been reported or are to be expected, the use of MRI during pregnancy is still limited to the second and third trimester of pregnancy. Magnetic resonance imaging contrast media are not to be used as it passes the placenta. Ultrasound remains the primary screening modality for fetal pathology; fetal MRI can serve as an adjunct or second-line imaging modality. (orig.)

  15. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Pei-Hsin; Chung, Hsiao-Wen [Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Tsai, Ping-Huei [Imaging Research Center, Taipei Medical University, Taipei 11031, Taiwan and Department of Medical Imaging, Taipei Medical University Hospital, Taipei Medical University, Taipei 11031, Taiwan (China); Wu, Ming-Long, E-mail: minglong.wu@csie.ncku.edu.tw [Institute of Medical Informatics, National Cheng-Kung University, Tainan 70101, Taiwan and Department of Computer Science and Information Engineering, National Cheng-Kung University, Tainan 70101, Taiwan (China); Chuang, Tzu-Chao [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Shih, Yi-Yu [Siemens Limited Healthcare Sector, Taipei 11503, Taiwan (China); Huang, Teng-Yi [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China)

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  16. Photo-magnetic Imaging: Resolving Optical Contrast at MRI resolution

    OpenAIRE

    Lin, Yuting; Gao, Hao; Thayer, David; Luk, Alex L.; Gulsen, Gultekin

    2013-01-01

    In this paper, we establish the mathematical framework of a novel imaging technique, namely Photo-magnetic Imaging (PMI). PMI uses laser to illuminate biological tissues and measure the induced temperature variations using magnetic resonance imaging (MRI). PMI overcomes the limitation of conventional optical imaging and allows imaging of optical contrast at MRI spatial resolution. The image reconstruction for PMI, using a finite element-based algorithm with iterative approach, is presented in...

  17. Multi-resolutional brain network filtering and analysis via wavelets on non-Euclidean space.

    Science.gov (United States)

    Kim, Won Hwa; Adluru, Nagesh; Chung, Moo K; Charchut, Sylvia; GadElkarim, Johnson J; Altshuler, Lori; Moody, Teena; Kumar, Anand; Singh, Vikas; Leow, Alex D

    2013-01-01

    Advances in resting state fMRI and diffusion weighted imaging (DWI) have led to much interest in studies that evaluate hypotheses focused on how brain connectivity networks show variations across clinically disparate groups. However, various sources of error (e.g., tractography errors, magnetic field distortion, and motion artifacts) leak into the data, and make downstream statistical analysis problematic. In small sample size studies, such noise have an unfortunate effect that the differential signal may not be identifiable and so the null hypothesis cannot be rejected. Traditionally, smoothing is often used to filter out noise. But the construction of convolving with a Gaussian kernel is not well understood on arbitrarily connected graphs. Furthermore, there are no direct analogues of scale-space theory for graphs--ones which allow to view the signal at multiple resolutions. We provide rigorous frameworks for performing 'multi-resolutional' analysis on brain connectivity graphs. These are based on the recent theory of non-Euclidean wavelets. We provide strong evidence, on brain connectivity data from a network analysis study (structural connectivity differences in adult euthymic bipolar subjects), that the proposed algorithm allows identifying statistically significant network variations, which are clinically meaningful, where classical statistical tests, if applied directly, fail.

  18. BabySQUID: A mobile, high-resolution multichannel magnetoencephalography system for neonatal brain assessment

    Science.gov (United States)

    Okada, Yoshio; Pratt, Kevin; Atwood, Christopher; Mascarenas, Anthony; Reineman, Richard; Nurminen, Jussi; Paulson, Douglas

    2006-02-01

    We developed a prototype of a mobile, high-resolution, multichannel magnetoencephalography (MEG) system, called babySQUID, for assessing brain functions in newborns and infants. Unlike electroencephalography, MEG signals are not distorted by the scalp or the fontanels and sutures in the skull. Thus, brain activity can be measured and localized with MEG as if the sensors were above an exposed brain. The babySQUID is housed in a moveable cart small enough to be transported from one room to another. To assess brain functions, one places the baby on the bed of the cart and the head on its headrest with MEG sensors just below. The sensor array consists of 76 first-order axial gradiometers, each with a pickup coil diameter of 6mm and a baseline of 30mm, in a high-density array with a spacing of 12-14mm center-to-center. The pickup coils are 6±1mm below the outer surface of the headrest. The short gap provides unprecedented sensitivity since the scalp and skull are thin (as little as 3-4mm altogether) in babies. In an electromagnetically unshielded room in a hospital, the field sensitivity at 1kHz was ˜17fT/√Hz. The noise was reduced from ˜400to200fT/√Hz at 1Hz using a reference cancellation technique and further to ˜40fT/√Hz using a gradient common mode rejection technique. Although the residual environmental magnetic noise interfered with the operation of the babySQUID, the instrument functioned sufficiently well to detect spontaneous brain signals from babies with a signal to noise ratio (SNR) of as much as 7.6:1. In a magnetically shielded room, the field sensitivity was 17fT/√Hz at 20Hz and 30fT/√Hz at 1Hz without implementation of reference or gradient cancellation. The sensitivity was sufficiently high to detect spontaneous brain activity from a 7month old baby with a SNR as much as 40:1 and evoked somatosensory responses with a 50Hz bandwidth after as little as four averages. We expect that both the noise and the sensor gap can be reduced further by

  19. Line broadening interference for high-resolution nuclear magnetic resonance spectra under inhomogeneous magnetic fields.

    Science.gov (United States)

    Wei, Zhiliang; Yang, Jian; Chen, Youhe; Lin, Yanqin; Chen, Zhong

    2015-04-01

    Nuclear magnetic resonance spectroscopy serves as an important tool for analyzing chemicals and biological metabolites. However, its performance is subject to the magnetic-field homogeneity. Under inhomogeneous fields, peaks are broadened to overlap each other, introducing difficulties for assignments. Here, we propose a method termed as line broadening interference (LBI) to provide high-resolution information under inhomogeneous magnetic fields by employing certain gradients in the indirect dimension to interfere the magnetic-field inhomogeneity. The conventional spectral-line broadening is thus interfered to be non-diagonal, avoiding the overlapping among adjacent resonances. Furthermore, an inhomogeneity correction algorithm is developed based on pattern recognition to recover the high-resolution information from LBI spectra. Theoretical deductions are performed to offer systematic and detailed analyses on the proposed method. Moreover, experiments are conducted to prove the feasibility of the proposed method for yielding high-resolution spectra in inhomogeneous magnetic fields.

  20. High-resolution mechanical imaging of glioblastoma by multifrequency magnetic resonance elastography.

    Directory of Open Access Journals (Sweden)

    Kaspar-Josche Streitberger

    Full Text Available OBJECTIVE: To generate high-resolution maps of the viscoelastic properties of human brain parenchyma for presurgical quantitative assessment in glioblastoma (GB. METHODS: Twenty-two GB patients underwent routine presurgical work-up supplemented by additional multifrequency magnetic resonance elastography. Two three-dimensional viscoelastic parameter maps, magnitude |G*|, and phase angle φ of the complex shear modulus were reconstructed by inversion of full wave field data in 2-mm isotropic resolution at seven harmonic drive frequencies ranging from 30 to 60 Hz. RESULTS: Mechanical brain maps confirmed that GB are composed of stiff and soft compartments, resulting in high intratumor heterogeneity. GB could be easily differentiated from healthy reference tissue by their reduced viscous behavior quantified by φ (0.37±0.08 vs. 0.58±0.07. |G*|, which in solids more relates to the material's stiffness, was significantly reduced in GB with a mean value of 1.32±0.26 kPa compared to 1.54±0.27 kPa in healthy tissue (P = 0.001. However, some GB (5 of 22 showed increased stiffness. CONCLUSION: GB are generally less viscous and softer than healthy brain parenchyma. Unrelated to the morphology-based contrast of standard magnetic resonance imaging, elastography provides an entirely new neuroradiological marker and contrast related to the biomechanical properties of tumors.

  1. Resolution Improvements in in Vivo1H NMR Spectra with Increased Magnetic Field Strength

    Science.gov (United States)

    Gruetter, Rolf; Weisdorf, Sally A.; Rajanayagan, Vasantham; Terpstra, Melissa; Merkle, Hellmut; Truwit, Charles L.; Garwood, Michael; Nyberg, Scott L.; Ugurbil, Kâmil

    1998-11-01

    The measurement of cerebral metabolites using highly homologous localization techniques and similar shimming methods was performed in the human brain at 1.5 and 4 T as well as in the dog and rat brain at 9.4 T. In rat brain, improved resolution was achieved by shimming all first- and second-order shim coils using a fully adiabatic FASTMAP sequence. The spectra showed a clear improvement in spectral resolution for all metabolite resonances with increased field strength. Changes in cerebral glutamine content were clearly observed at 4 T compared to 1.5 T in patients with hepatic encephalopathy. At 9.4 T, glutamine H4 at 2.46 ppm was fully resolved from glutamate H4 at 2.37 ppm, as was the potential resonance from γ-amino-butyric acid at 2.30 ppm and N-acetyl-aspartyl-glutamate at 2.05 ppm. Singlet linewidths were found to be as low as 6 Hz (0.015 ppm) at 9.4 T, indicating a substantial decrease in ppm linewidth with field strength. Furthermore, the methylene peak of creatine was partially resolved from phosphocreatine, indicating a close to 1:1 relationship in gray matter. We conclude that increasing the magnetic field strength increases spectral resolution also for1H NMR, which can lead to more than linear sensitivity gains.

  2. Modelling Brain Tissue using Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Dyrby, Tim Bjørn

    2008-01-01

    Diffusion MRI, or diffusion weighted imaging (DWI), is a technique that measures the restricted diffusion of water molecules within brain tissue. Different reconstruction methods quantify water-diffusion anisotropy in the intra- and extra-cellular spaces of the neural environment. Fibre tracking...... be used. Within a two year period, no statistical inter- or intra-brain difference in the diffusion coefficient was found in perfusion fixated minipig brains. However, a decreasing tendency in the diffusion coefficient was found at the last time points about 24 months post mortem and might be explained...... experiment. This includes the selection of independent anatomical data to be used to derive a gold standard, the selection of a gyrated animal model in place of the human brain, objective selection of the seed region to initiate, and a waypoint region to constrain the tractography results....

  3. Resolution and sensitivity of high field nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    The arrival of very high field magnets and cryogenic circuitries, and the development of relaxation-optimized pulse sequences have added powerful tools for increasing sensitivity and resolution in NMR studies of biomacromolecules. The potential of these advances is not fully realized in practice, however, since current experimental protocols do not permit sufficient data sampling for optimal resolution in the indirect dimensions. Here we analyze quantitatively how increasing resolution in indirect dimensions affects the S/N ratio and compare this with currently used sampling routines. Optimal resolution would require sampling up to ∼3R2-1, and the S/N reaches a maximum at ∼1.2R2-1. Currently used data acquisition protocols rarely sample beyond 0.4R2-1, and extending evolution times would result in prohibitively long experiments. We show that a general solution to this problem is to use non-uniform sampling, where only a small subset of data points in the indirect sampling space are measured, and possibly different numbers of transients are collected for different evolution times. Coupled with modern methods of spectrum analysis, this strategy delivers substantially improved resolution and/or reduced measuring times compared to uniform sampling, without compromising sensitivity. Higher resolution in the indirect dimensions will facilitate the use of automated assignment programs

  4. Metabolic Syndrome, Brain Magnetic Resonance Imaging, and Cognition

    OpenAIRE

    Cavalieri, Margherita; Ropele, Stefan; Petrovic, Katja; Pluta-Fuerst, Aga; Homayoon, Nina; Enzinger, Christian; Grazer, Anja; Katschnig, Petra; Schwingenschuh, Petra; Berghold, Andrea; Schmidt, Reinhold

    2010-01-01

    OBJECTIVE We explored cognitive impairment in metabolic syndrome in relation to brain magnetic resonance imaging (MRI) findings. RESEARCH DESIGN AND METHODS We studied 819 participants free of clinical stroke and dementia of the population-based Austrian Stroke Prevention Study who had undergone brain MRI, neuropsychological testing, and a risk factor assessment relevant to National Cholesterol Education Program Adult Treatment Panel III criteria–defined metabolic syndrome. High-sensitivity C...

  5. Analysis of Magnetic Field Inducted in Brain by Multi-Channel Magnetic Stimulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Multi-channel magnetic stimulation is an efficient method to improve the conventional magnetic stimulation. A multi-channel magnetic brain stimulator was developed and the distribution of magnetic field was calculated by finite-element analysis software-ANSYS. The results show that when five coils work simultaneously, the area where the magnetic flux density is larger than 0.01 T would expand to almost the whole brain region, and the magnetic stimulation depth would be improved.Experiments were performed on ten subjects (mean age 25) using the stimulator, and the EEG power spectrums before and after stimulation were analyzed. The experimental results show that the beta component of EEG obviously increases after magnetic stimulation, and the effect is more obvious by using more coils simultaneously because of the deeper stimulation.

  6. Brain magnetic resonance imaging of infants exposed prenatally to buprenorphine

    International Nuclear Information System (INIS)

    Purpose: To evaluate the brains of newborns exposed to buprenorphine prenatally. Material and Methods: Seven neonates followed up antenatally in connection with their mothers' buprenorphine replacement therapy underwent 1.5T magnetic resonance imaging (MRI) of the brain before the age of 2 months. The infants were born to heavy drug abusers. Four mothers were hepatitis C positive, and all were HIV negative. All mothers smoked tobacco and used benzodiazepines. All pregnancies were full term, and no perinatal asphyxia occurred. All but one neonate had abstinence syndrome and needed morphine replacement therapy. Results: Neither structural abnormalities nor abnormalities in signal intensity were recorded. Conclusion: Buprenorphine replacement therapy does not seem to cause any major structural abnormalities of the brain, and it may prevent known hypoxic-ischemic brain changes resulting from uncontrolled drug abuse. Longitudinal studies are needed to assess possible abnormalities in the brain maturation process

  7. Magnetic resonance studies of brain function and neurochemistry

    OpenAIRE

    Uǧurbil, K.; Adriany, G.; Andersen, P; Chen, W.; Gruetter, R.; Hu, X.; Merkle, H; Kim, D.-S.; Kim, S. -G.; Strupp, J.; Zhu, X H; Ogawa, S

    2000-01-01

    In the short time since its introduction, magnetic resonance imaging (MRI) has rapidly evolved to become an indispensable tool for clinical diagnosis and biomedical research. Recently, this methodology has been successfully used for the acquisition of functional, physiological, and biochemical information in intact systems, particularly in the human body. The ability to map areas of altered neuronal activity in the brain, often referred to as functional magnetic resonance imaging (fMRI), is p...

  8. Magnetic micelles for DNA delivery to rat brains after mild traumatic brain injury.

    Science.gov (United States)

    Das, Mahasweta; Wang, Chunyan; Bedi, Raminder; Mohapatra, Shyam S; Mohapatra, Subhra

    2014-10-01

    Traumatic brain injury (TBI) causes significant mortality, long term disability and psychological symptoms. Gene therapy is a promising approach for treatment of different pathological conditions. Here we tested chitosan and polyethyleneimine (PEI)-coated magnetic micelles (CP-mag micelles or CPMMs), a potential MRI contrast agent, to deliver a reporter DNA to the brain after mild TBI (mTBI). CPMM-tomato plasmid (ptd) conjugate expressing a red-fluorescent protein (RFP) was administered intranasally immediately after mTBI or sham surgery in male SD rats. Evans blue extravasation following mTBI suggested CPMM-ptd entry into the brain via the compromised blood-brain barrier. Magnetofection increased the concentration of CPMMs in the brain. RFP expression was observed in the brain (cortex and hippocampus), lung and liver 48 h after mTBI. CPMM did not evoke any inflammatory response by themselves and were excreted from the body. These results indicate the possibility of using intranasally administered CPMM as a theranostic vehicle for mTBI. From the clinical editor: In this study, chitosan and PEI-coated magnetic micelles (CPMM) were demonstrated as potentially useful vehicles in traumatic brain injury in a rodent model. Magnetofection increased the concentration of CPMMs in the brain and, after intranasal delivery, CPMM did not evoke any inflammatory response and were excreted from the body. PMID:24486465

  9. Modelling Brain Tissue using Magnetic Resonance Imaging

    OpenAIRE

    Dyrby, Tim Bjørn; Hansen, Lars Kai

    2008-01-01

    Diffusion MRI, or diffusion weighted imaging (DWI), is a technique that measures the restricted diffusion of water molecules within brain tissue. Different reconstruction methods quantify water-diffusion anisotropy in the intra- and extra-cellular spaces of the neural environment. Fibre tracking models then use the directions of greatest diffusion as estimates of white matter fibre orientation. Several fibre tracking algorithms have emerged in the last few years that provide reproducible visu...

  10. The psychopath magnetized: insights from brain imaging

    OpenAIRE

    Anderson, Nathaniel E.; Kiehl, Kent A.

    2011-01-01

    Psychopaths commit a disproportionate amount of violent crime, and this places a substantial economic and emotional burden on society. Elucidation of the neural correlates of psychopathy may lead to improved management and treatment of the condition. Although some methodological issues remain, the neuroimaging literature is generally converging on a set of brain regions and circuits that are consistently implicated in the condition: the orbitofrontal cortex, amygdala, and the anterior and pos...

  11. In vivo high-resolution diffusion tensor imaging of the mouse brain.

    Science.gov (United States)

    Wu, Dan; Xu, Jiadi; McMahon, Michael T; van Zijl, Peter C M; Mori, Susumu; Northington, Frances J; Zhang, Jiangyang

    2013-12-01

    Diffusion tensor imaging (DTI) of the laboratory mouse brain provides important macroscopic information for anatomical characterization of mouse models in basic research. Currently, in vivo DTI of the mouse brain is often limited by the available resolution. In this study, we demonstrate in vivo high-resolution DTI of the mouse brain using a cryogenic probe and a modified diffusion-weighted gradient and spin echo (GRASE) imaging sequence at 11.7 T. Three-dimensional (3D) DTI of the entire mouse brain at 0.125 mm isotropic resolution could be obtained in approximately 2 h. The high spatial resolution, which was previously only available with ex vivo imaging, enabled non-invasive examination of small structures in the adult and neonatal mouse brains. Based on data acquired from eight adult mice, a group-averaged DTI atlas of the in vivo adult mouse brain with 60 structure segmentations was developed. Comparisons between in vivo and ex vivo mouse brain DTI data showed significant differences in brain morphology and tissue contrasts, which indicate the importance of the in vivo DTI-based mouse brain atlas.

  12. Pattern recognition on brain magnetic resonance imaging in alpha dystroglycanopathies

    Directory of Open Access Journals (Sweden)

    Bindu Parayil

    2010-01-01

    Full Text Available Alpha dystroglycanopathies are heterogeneous group of disorders both phenotypically and genetically. A subgroup of these patients has characteristic brain imaging findings. Four patients with typical imaging findings of alpha dystroglycanopathy are reported. Phenotypic features included: global developmental delay, contractures, hypotonia and oculomotor abnormalities in all. Other manifestations were consanguinity (3, seizures (3, macrocephaly (1, microcephaly (3, retinal changes (2 and hypogenitalism (2. Magnetic resonance imaging (MRI of the brain revealed polymicrogyria, white matter changes, pontine hypoplasia, and subcortical cerebellar cysts in all the patients, ventriculomegaly, callosal abnormalities, and absent septum pellucidum in two and Dandy -Walker variant malformation in three. Magnetic resonace imaging of the first cousin of one the patient had the same characteristic imaging features. Brain imaging findings were almost identical despite heterogeneity in clinical presentation and histopathological features. Pattern recognition of MR imaging features may serve as a clue to the diagnosis of alpha dystroglycanopathy.

  13. Normal feline brain: clinical anatomy using magnetic resonance imaging.

    Science.gov (United States)

    Mogicato, G; Conchou, F; Layssol-Lamour, C; Raharison, F; Sautet, J

    2012-04-01

    The purpose of this study was to provide a clinical anatomy atlas of the feline brain using magnetic resonance imaging (MRI). Brains of twelve normal cats were imaged using a 1.5 T magnetic resonance unit and an inversion/recovery sequence (T1). Fourteen relevant MRI sections were chosen in transverse, dorsal, median and sagittal planes. Anatomic structures were identified and labelled using anatomical texts and Nomina Anatomica Veterinaria, sectioned specimen heads, and previously published articles. The MRI sections were stained according to the major embryological and anatomical subdivisions of the brain. The relevant anatomical structures seen on MRI will assist clinicians to better understand MR images and to relate this neuro-anatomy to clinical signs.

  14. High resolution spectroscopy in solids by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    The nuclear magnetic resonance (NMR) techniques for High Resolution Spectroscopy in Solids are described. Also the construction project of a partially home made spectrometer and its applications in the characterization of solid samples are shown in detail. The high resolution spectrometer used is implemented with the double resonance multiple pulses sequences and magic angle spinning (MAS) and can be used with solid and liquid samples. The maximum spinning frequency for the MAS experiment is in excess of 5 Khz, the double resonance sequences can be performed with any type of nucleus, in the variable temperature operating range with nitrogen gas: -1200 C to +1600 C, and is fully controlled by a Macintosh IIci microcomputer. (author)

  15. Magnetic resonance imaging based volumetry: a primary approach to unravelling the brain

    Institute of Scientific and Technical Information of China (English)

    Huang Xiaoqi; Lü Su; Li Dongming; Gong Qiyong

    2007-01-01

    Magnetic resonance (MR) imaging based volumetry is recognized as an important technique for studying the brain. In this review, two principle volumetric methods using high resolution MR images were introduced, namely the Cavalieri method and the voxel based morphometry (VBM). The Cavalieri method represents a manual technique that allows the volume of brain structures to be estimated efficiently with no systematic error or sampling bias, whereby the VBM represents an automated image analysis which involves the use of statistical parametric mapping of the MR imaging data. Both methods have been refined and applied extensively in recent neuroscience research. The present paper aims to describe the development of methodologies and also to update the knowledge of their applications in studying the normal and diseased brain.

  16. Magnetic resonance and the human brain: anatomy, function and metabolism.

    Science.gov (United States)

    Talos, I-F; Mian, A Z; Zou, K H; Hsu, L; Goldberg-Zimring, D; Haker, S; Bhagwat, J G; Mulkern, R V

    2006-05-01

    The introduction and development, over the last three decades, of magnetic resonance (MR) imaging and MR spectroscopy technology for in vivo studies of the human brain represents a truly remarkable achievement, with enormous scientific and clinical ramifications. These effectively non-invasive techniques allow for studies of the anatomy, the function and the metabolism of the living human brain. They have allowed for new understandings of how the healthy brain works and have provided insights into the mechanisms underlying multiple disease processes which affect the brain. Different MR techniques have been developed for studying anatomy, function and metabolism. The primary focus of this review is to describe these different methodologies and to briefly review how they are being employed to more fully appreciate the intricacies associated with the organ, which most distinctly differentiates the human species from the other animal forms on earth. PMID:16568243

  17. Preliminary study in vitro brain tumor with high resolution magic angle spinning proton magnetic resonance spectroscopy%离体脑肿瘤高分辨魔角旋转磁共振质子波谱

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Objective: To explore water soluble metabolite features of brain tumor specimens with HRMAS-1HMRS and its potential clinical value.Methods: There were thirty cases of pathologically proven brain tumor, including 6Ⅰ-Ⅱgrade astrocytomas, 7Ⅲgrade anaplastic astrocytomas, 10 IV grade glioblastomas and 7 meningiomas.Used Varian Company 600 MHz spectrometer with the Nano-probe for acquisition HRMAS-1HMRS, which was postprocessed with jMRUI 3.2 version software.These metabolic probability and their ratios to Cr were summed.Results: (1)HRMAS-1HMRS could resolve NAA, PCr/Cr, GPC+Pcho+Cho, Ghu/Gin, Gly, Tau, Ala, Lac, ml and so on.All samples showed Lac, 6 samples showed unknown single peak at 3.72 ppm or 3.90 ppm.(2)The mean Cho/Cr of 6Ⅰ-Ⅱgrade astrocytomas was 2.42±1.01(P=0.003, compared with glioblastoma).The mean Cho/Cr of 7 anaplastic astrocytomas was 3.48±0.59 (P=0.01, compared with glioblastoma).The Cho/Cr of 10 glioblastomas broadly ranged from 0.9 to 11.3 (mean 5.40±1.23).FromⅠ-Ⅱgrade astrocytoma to glioblastoma, Ala/Cr, Tau/Cr and Gly/Cr trends were increased; the mean Ala/Cr of glioma was 0.31±0.13.(3)Meningiomas showed higher Ala and Cho.Their Cr was lower than that of gliomas.4/7 cases had no NAA, 3/7 patients had lower NAA.Mean Cho/Cr was 3.56±1.01, Ala/Cr was 0.53±0.28(P=0.006, compared with glioma).Conclusion: HRMAS-1HMRS can show further details in vivo MRS, resolve in vivo spectroscopic metabolite of Cho compound and differentiate the extent of benign and malignant glioma.With the increase in the malignant degree of gliomas, Cho, ml, Ala, Tau and Gly will increase.HRMAS-1HMRS is the only method of isotropic spectroscopy for pathological specimens.

  18. Thresholding magnetic resonance images of human brain

    Institute of Scientific and Technical Information of China (English)

    Qing-mao HU; Wieslaw L NOWINSKI

    2005-01-01

    In this paper, methods are proposed and validated to determine low and high thresholds to segment out gray matter and white matter for MR images of different pulse sequences of human brain. First, a two-dimensional reference image is determined to represent the intensity characteristics of the original three-dimensional data. Then a region of interest of the reference image is determined where brain tissues are present. The non-supervised fuzzy c-means clustering is employed to determine: the threshold for obtaining head mask, the low threshold for T2-weighted and PD-weighted images, and the high threshold for T1-weighted, SPGR and FLAIR images. Supervised range-constrained thresholding is employed to determine the low threshold for T1-weighted, SPGR and FLAIR images. Thresholding based on pairs of boundary pixels is proposed to determine the high threshold for T2- and PD-weighted images. Quantification against public data sets with various noise and inhomogeneity levels shows that the proposed methods can yield segmentation robust to noise and intensity inhomogeneity. Qualitatively the proposed methods work well with real clinical data.

  19. Development of a high angular resolution diffusion imaging human brain template.

    Science.gov (United States)

    Varentsova, Anna; Zhang, Shengwei; Arfanakis, Konstantinos

    2014-05-01

    Brain diffusion templates contain rich information about the microstructure of the brain, and are used as references in spatial normalization or in the development of brain atlases. The accuracy of diffusion templates constructed based on the diffusion tensor (DT) model is limited in regions with complex neuronal micro-architecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DT model and is capable of resolving intravoxel heterogeneity. However, when HARDI is combined with multiple-shot sequences to minimize image artifacts, the scan time becomes inappropriate for human brain imaging. In this work, an artifact-free HARDI template of the human brain was developed from low angular resolution multiple-shot diffusion data. The resulting HARDI template was produced in ICBM-152 space based on Turboprop diffusion data, was shown to resolve complex neuronal micro-architecture in regions with intravoxel heterogeneity, and contained fiber orientation information consistent with known human brain anatomy.

  20. Magnetic resonance elastography in normal human brain: preliminary study

    International Nuclear Information System (INIS)

    Objective: To study the application of magnetic resonance elastography (MRE) in the human brain. Methods: An external force actuator was developed. The actuator was fixed to the head coil. During MRE scan, one side of the actuator was attached to the volunteers' head. Low frequency oscillation was produced by the actuator and generated shear waves propagating into brain tissue. The pulse sequence of MRE was designed. A modified gradient echo sequence was developed with motion sensitizing gradient (MSG) imposed along X, Y or Z direction. Cyclic displacement within brain tissue induced by shear waves caused a measurable phase shift in the received MR signal. From the measured phase shift, the displacement at each voxel could be calculated, and the shear waves within the brain were directly imaged. By adjusting the phase offset, the dynamic propagation of shear waves in a wave cycle was obtained. Phase images were processed with local frequency estimation (LFE) technique to obtain the elasticity images. Shear waves at 100 Hz, 150 Hz, and 200 Hz were applied. Results: The phase images of MRE directly imaged the propagating shear waves within the brain. The direction of the propagation was from surface of the brain to the center. The wavelength of shear waves varied with the change of actuating frequency. The change of wavelength of shear waves in gray and white matter of the brain was identified. The wavelength of shear waves in gray matter was shorter than that in white matter. The elasticity image of the brain revealed that the shear modulus of the white matter was higher than that of gray matter. Conclusion: The phase images of MRE can directly visualize the propagation of shear waves in the brain tissue. The elasticity image of the brain can demonstrate the change of elasticity between gray and white matter. (authors)

  1. STEREOLOGICAL EVALUATION OF BRAIN MAGNETIC RESONANCE IMAGES OF SCHIZOPHRENIC PATIENTS

    Directory of Open Access Journals (Sweden)

    Amani Abdelrazag Elfaki

    2013-11-01

    Full Text Available Advances in neuroimaging have enabled studies of specific neuroanatomical abnormalities with relevance to schizophrenia. This study quantified structural alterations on brain magnetic resonance (MR images of patients with schizophrenia. MR brain imaging was done on 88 control and 57 schizophrenic subjects and Dicom images were analyzed with ImageJ software. The brain volume was estimated with the planimetric stereological technique. The volume fraction of brain structures was also estimated. The results showed that, the mean volume of right, left, and total hemispheres in controls were 551, 550, and 1101 cm³, respectively. The mean volumes of right, left, and total hemispheres in schizophrenics were 513, 512, and 1026 cm³, respectively. The schizophrenics’ brains were smaller than the controls (p < 0.05. The mean volume of total white matter of controls (516 cm³ was bigger than the schizophrenics’ volume (451 cm³, (p < 0.05. The volume fraction of total white matter was also lower in schizophrenics (p < 0.05. Volume fraction of the lateral ventricles was higher in schizophrenics (p < 0.05. According to the findings, the volumes of schizophrenics’ brain were smaller than the controls and the volume fractional changes in schizophrenics showed sex dependent differences. We conclude that stereological analysis of MR brain images is useful for quantifying schizophrenia related structural changes.

  2. 3D high spectral and spatial resolution imaging of ex vivo mouse brain

    Energy Technology Data Exchange (ETDEWEB)

    Foxley, Sean, E-mail: sean.foxley@ndcn.ox.ac.uk; Karczmar, Gregory S. [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States); Domowicz, Miriam [Department of Pediatrics, University of Chicago, Chicago, Illinois 60637 (United States); Schwartz, Nancy [Department of Pediatrics, Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637 (United States)

    2015-03-15

    Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T{sub 2}{sup *}-weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T{sub 2}{sup *} and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm{sup 3} and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T{sub 2}{sup *}-weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in

  3. Brain size and brain organization of the whale shark, Rhincodon typus, using magnetic resonance imaging.

    Science.gov (United States)

    Yopak, Kara E; Frank, Lawrence R

    2009-01-01

    Very little is known about the brain organization of the suction filter feeder, Rhincodon typus, and how it compares to other orectolobiforms in light of its specialization as a plankton-feeder. Brain size and overall brain organization was assessed in two specimens of R. typus in relation to both phylogeny and ecology, using magnetic resonance imaging (MRI). In comparison to over 60 other chondrichthyan species, R. typus demonstrated a relatively small brain for its body size (expressed in terms of encephalization quotients and residuals), similar to the lamniforms Carcharodon carcharias, Cetorhinus maximus, and Carcharias taurus. R. typus possessed a relatively small telencephalon with some development of the dorsal pallium, which was suggestive of moderate social behavior, in addition to a relatively large diencephalon and a relatively reduced mesencephalon. The most notable characteristic of the brain of Rhincodon was a large and highly foliated cerebellum, one of the largest cerebellums within the chondrichthyan clade. Early development of the brain was qualitatively assessed using an in situ MRI scan of the brain and chondrocranium of a neonate specimen of R. typus. There was evidence that folding of the cerebellar corpus appeared in early development, although the depth and number of folds might vary ontogenetically in this species. Hierarchical cluster analysis and multidimensional scaling ordinations showed evidence of convergent evolution with the basking shark, Cetorhinus maximus, another large-bodied filter feeding elasmobranch, supporting the claim that organization of the brain is more similar in species with analogous but independently evolved lifestyles than those that share taxonomic classification.

  4. Community detection in weighted brain connectivity networks beyond the resolution limit

    CERN Document Server

    Nicolini, Carlo; Bifone, Angelo

    2016-01-01

    Graph theory provides a powerful framework to investigate brain functional connectivity networks and their modular organization. However, most graph-based methods suffer from a fundamental resolution limit that may have affected previous studies and prevented detection of modules, or communities, that are smaller than a specific scale. Surprise, a resolution-limit-free function rooted in discrete probability theory, has been recently introduced and applied to brain networks, revealing a wide size-distribution of functional modules, in contrast with many previous reports. However, the use of Surprise is limited to binary networks, while brain networks are intrinsically weighted, reflecting a continuous distribution of connectivity strengths between different brain regions. Here, we propose Asymptotical Surprise, a continuous version of Surprise, for the study of weighted brain connectivity networks, and validate this approach in synthetic networks endowed with a ground-truth modular structure. We compare Asymp...

  5. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W. (AT and T Bell Laboratories, Murray Hill, NJ (United States))

    1990-12-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity.

  6. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    International Nuclear Information System (INIS)

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity

  7. A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy.

    Science.gov (United States)

    Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

    2016-01-01

    A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia.

  8. Clinical anatomy of the canine brain using magnetic resonance imaging.

    Science.gov (United States)

    Leigh, Edmund J; Mackillop, Edward; Robertson, Ian D; Hudson, Lola C

    2008-01-01

    The purpose of this study was to produce an magnetic resonsnce (MR) image atlas of clinically relevant brain anatomy and to relate this neuroanatomy to clinical signs. The brain of a large mixed breed dog was imaged in transverse, sagittal, and dorsal planes using a 1.5 T MR unit and the following pulse sequences: Turbo (fast) spin echo (TSE) T2, T1, and T2- weighted spatial and chemical shift-encoded excitation sequence. Relevant neuroanatomic structures were identified using anatomic texts, sectioned cadaver heads, and previously published atlases. Major subdivisions of the brain were mapped and the neurologic signs of lesions in these divisions were described. TSE T2-weighted images were found to be the most useful for identifying clinically relevant neuroanatomy. Relating clinical signs to morphology as seen on MR will assist veterinarians to better understand clinically relevant neuroanatomy in MR images. PMID:18418990

  9. Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain

    Science.gov (United States)

    Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

    1998-12-01

    Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.

  10. Reversible lesions in the brain parenchyma in Wilson's disease confirmed by magnetic resonance imaging: earlier administration of chelating therapy can reduce the damage to the brain.

    Science.gov (United States)

    Kozić, Duško B; Petrović, Igor; Svetel, Marina; Pekmezović, Tatjana; Ragaji, Aleksandar; Kostić, Vladimir S

    2014-11-01

    The aim of this study was to evaluate the resolution of brain lesions in patients with Wilson's disease during the long-term chelating therapy using magnetic resonance imaging and a possible significance of the time latency between the initial symptoms of the disease and the introduction of this therapy. Initial magnetic resonance examination was performed in 37 patients with proven neurological form of Wilson's disease with cerebellar, parkinsonian and dystonic presentation. Magnetic resonance reexamination was done 5.7 ± 1.3 years later in 14 patients. Patients were divided into: group A, where chelating therapy was initiated < 24 months from the first symptoms and group B, where the therapy started ≥ 24 months after the initial symptoms. Symmetry of the lesions was seen in 100% of patients. There was a significant difference between groups A and B regarding complete resolution of brain stem and putaminal lesions (P = 0.005 and P = 0.024, respectively). If the correct diagnosis and adequate treatment are not established less than 24 months after onset of the symptoms, irreversible lesions in the brain parenchyma could be expected. Signal abnormalities on magnetic resonance imaging might therefore, at least in the early stages, represent reversible myelinolisis or cytotoxic edema associated with copper toxicity.

  11. Magnetic field effects on brain monoamine oxidase activity

    Energy Technology Data Exchange (ETDEWEB)

    Borets, V.M.; Ostrovskiy, V.Yu.; Bankovskiy, A.A.; Dudinskaya, T.F.

    1985-03-01

    In view of the increasing use of magnetotherapy, studies were conducted on the effects of 35 mTesla magnetic fields on monoamine oxidase activity in the rat brain. Under in vitro conditions a constant magnetic field in the continuous mode was most effective in inhibiting deamination of dopamine following 1 min exposure, while in vivo studies with 8 min or 10 day exposures showed that inhibition was obtained only with a variable field in the continuous mode. However, inhibition of dopamine deamination was only evident within the first 24 h after exposure was terminated. In addition, in none of the cases was norepinephrine deamination inhibited. The effects of the magnetic fields were, therefore, transient and selective with the CNS as the target system. 9 references.

  12. Development of identification of the central sulcus in brain magnetic resonance imaging.

    Science.gov (United States)

    Hayashi, Norio; Sakuta, Keita; Minehiro, Kaori; Takanaga, Masako; Sanada, Shigeru; Suzuki, Masayuki; Miyati, Tosiaki; Yamamoto, Tomoyuki; Matsui, Osamu

    2011-01-01

    Magnetic resonance imaging (MRI) is useful in the quantitative evaluation of brain atrophy, because the superior contrast resolution facilitates separation of the gray and white matter. Quantitative assessment of brain atrophy has mainly been performed by manual measurement, which requires considerable time and effort to determine the brain volume. Therefore, computer-aided quantitative measurement methods for the diagnosis of brain atrophy are required. We have developed a method of segmenting the cerebrum, cerebellum-brainstem, and temporal lobe simultaneously on MR images obtained in a single sequence. It is important to measure the volume of not only these regions but also the frontal lobe in clinical use. However, for segmenting the frontal lobe, it is necessary to identify the Sylvian fissure and the central sulcus, which represent boundaries. Here, we developed a method of identifying the central sulcus from MR images obtained with a 1.5 T MRI scanner. The brain and the cerebrospinal fluid (CSF) regions were segmented using semiautomated segmentation method on MR images. The central sulcus shows an oblique line from the inside to the outside on the convexity view. The almost straight appearance of the central sulcus was used for segmentation of the central sulcus from the segmented CSF images. The central sulcus was identified with this technique in 77% of the images obtained by all sequences. This technique for identifying the central sulcus is very important not only for volumetry, but also for clinical diagnosis.

  13. Grooved multi-pole magnetic gratings for high-resolution positioning systems

    Science.gov (United States)

    Xu, Zhi-Hao; Tseng, Bin-Hui; Chang, Ching; Wang, Sheng-Ching; Chin, Tsung-Shune; Sung, Cheng-Kuo

    2015-06-01

    Magnetic encoders are much advantageous for precision positioning specifically under harsh environments. The finer the magnetic pole-pitches of the magnetic scale in a magnetic encoder the higher the resolution of the encoder. In this paper, a grooved multi-pole magnetic grating (MPMG) is substituted for conventional non-structured magnetic scale. A MPMG with pole-pitch of 200 µm was prepared by photo-lithography and electro-deposition. Simulation was first done to attain the relationship among magnetic flux density, magnetic properties of electrodeposited alloy layers, magnetizing directions and the grating dimensions. The MPMG can be fully magnetized for use by just a single pulse in a solenoid coil. Magnetic properties were investigated in which CoNiP layers were electrodeposited under various current densities. Measured magnetic flux densities versus grating heights, magnetizing directions and detection gaps on magnetized MPMG validate the applicability of ultra-fine pitched MPMG.

  14. High-Resolution Mapping of Myeloarchitecture In Vivo: Localization of Auditory Areas in the Human Brain.

    Science.gov (United States)

    De Martino, Federico; Moerel, Michelle; Xu, Junqian; van de Moortele, Pierre-Francois; Ugurbil, Kamil; Goebel, Rainer; Yacoub, Essa; Formisano, Elia

    2015-10-01

    The precise delineation of auditory areas in vivo remains problematic. Histological analysis of postmortem tissue indicates that the relation of areal borders to macroanatomical landmarks is variable across subjects. Furthermore, functional parcellation schemes based on measures of, for example, frequency preference (tonotopy) remain controversial. Here, we propose a 7 Tesla magnetic resonance imaging method that enables the anatomical delineation of auditory cortical areas in vivo and in individual brains, through the high-resolution visualization (0.6 × 0.6 × 0.6 mm(3)) of intracortical anatomical contrast related to myelin. The approach combines the acquisition and analysis of images with multiple MR contrasts (T1, T2*, and proton density). Compared with previous methods, the proposed solution is feasible at high fields and time efficient, which allows collecting myelin-related and functional images within the same measurement session. Our results show that a data-driven analysis of cortical depth-dependent profiles of anatomical contrast allows identifying a most densely myelinated cortical region on the medial Heschl's gyrus. Analyses of functional responses show that this region includes neuronal populations with typical primary functional properties (single tonotopic gradient and narrow frequency tuning), thus indicating that it may correspond to the human homolog of monkey A1. PMID:24994817

  15. Mapping fetal brain development in utero using magnetic resonance imaging: the Big Bang of brain mapping.

    Science.gov (United States)

    Studholme, Colin

    2011-08-15

    The development of tools to construct and investigate probabilistic maps of the adult human brain from magnetic resonance imaging (MRI) has led to advances in both basic neuroscience and clinical diagnosis. These tools are increasingly being applied to brain development in adolescence and childhood, and even to neonatal and premature neonatal imaging. Even earlier in development, parallel advances in clinical fetal MRI have led to its growing use as a tool in challenging medical conditions. This has motivated new engineering developments encompassing optimal fast MRI scans and techniques derived from computer vision, the combination of which allows full 3D imaging of the moving fetal brain in utero without sedation. These promise to provide a new and unprecedented window into early human brain growth. This article reviews the developments that have led us to this point, examines the current state of the art in the fields of fast fetal imaging and motion correction, and describes the tools to analyze dynamically changing fetal brain structure. New methods to deal with developmental tissue segmentation and the construction of spatiotemporal atlases are examined, together with techniques to map fetal brain growth patterns.

  16. Magnetoencephalography - a noninvasive brain imaging method with 1 ms time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, Cosimo; Pizzella, Vittorio; Romani, Gian Luca [Department of Clinical Sciences and Bioimaging, University ' G D' Annunzio' , Chieti (Italy); ITAB-Institute for Advanced Biomedical Technologies, University ' G D' Annunzio' , (Italy); INFM-National Institute for the Physics of Matter, Research Unit of L' Aquila (Italy); Tecchio, Franca [IESS-Institute for Solid State Electronics, National Council of Research, Rome (Italy)

    2001-12-01

    The basics of magnetoencephalography (MEG), i.e. the measurement and the analysis of the tiny magnetic fields generated outside the scalp by the working human brain, are reviewed. Three main topics are discussed: (1) the relationship between the magnetic field and its generators, including on one hand the neurophysiological basis and the physical theory of magnetic field generation, and on the other hand the techniques for the estimation of the sources from the magnetic field measurements; (2) the instrumental techniques and the laboratory practice of neuromagnetic field measurement and (3) the main applications of MEG in basic neurophysiology as well as in clinical neurology. (author)

  17. Localization and distribution of magnetic chemotherapeutic drugs with magnetic targeting in rat brain

    Institute of Scientific and Technical Information of China (English)

    LI An-min; ZHANG Chuan-xiu; FU Xiang-ping; ZHANG Zhi-wen; XUE Qing-hui; YAN Run-min; YI Lin-hua

    2005-01-01

    Background Magnetic targeting therapy may be a new method for the treatment of malignent tumors. The purpose of this study was to investigate the localization and distribution of ferrofluid microsphere of human serum albumin methotrexate (FM-HSA-MTX) carriers in the brain and to explore the magnetic targeting chemotherapy for malignant brain tumor. Methods Ninety SD rats were divided into three groups: targeting group, non-magnetic targeting group, and control group. Synthesized FM-HSA-MTX carriers (MTX 25 mg/kg) were injected into the systemic circulation via the caudal vein (magnetic targeting group, n=30). A 0.6 T magnetic field was placed around the right hemisphere. The non-magnetic targeting group (n=30) was administered with FM-HSA-MTX without external magnetic field, meanwhile the control group (n=30) was treated with MTX and a magnetic field. Random serial sacrifices (n=10) were conducted at 15, 30 and 45 minutes after drug administration. Bilateral hemispheres were collected respectively, and analyzed for total MTX content. Results MTX content in the right hemisphere of the magnetic targeting group was significantly higher than that in the other two groups at 15, 30 and 45 minutes after drug administration (P<0.05) No difference was seen between the non-targeting group and control group. In the magnetic targeting group, MTX returned to the peak level [(0.564±0.018) mg/g, q15-45=32.252, P<0.05] 45 minutes after the injection but it deceased in the other two groups [non-magnetic targeting group: (0.060±0.015) mg/g, q15-45=9.245, P<0.05, control group: (0.074±0.045) mg/g, q15-45=6.299, P<0.05]. In the magnetic targeting group, the concentration of MTX in the right hemisphere was significantly higher than that in the left hemisphere (t45min=21.135, P=0.000) but no difference was observed between bilateral hemispheres in the other two groups (non-magnetic targeting group: t45min=0.434, P=0.670; control group: t45min=0.533, P=0.600). Conclusion In

  18. High-Resolution and Quantitative X-Ray Phase-Contrast Tomography for Mouse Brain Research

    OpenAIRE

    Yan Xi; Xiaojie Lin; Falei Yuan; Guo-Yuan Yang; Jun Zhao

    2015-01-01

    Imaging techniques for visualizing cerebral vasculature and distinguishing functional areas are essential and critical to the study of various brain diseases. In this paper, with the X-ray phase-contrast imaging technique, we proposed an experiment scheme for the ex vivo mouse brain study, achieving both high spatial resolution and improved soft-tissue contrast. This scheme includes two steps: sample preparation and volume reconstruction. In the first step, we use heparinized saline to displa...

  19. Comparative mouse brain tractography of diffusion magnetic resonance imaging

    Science.gov (United States)

    Moldrich, Randal X.; Pannek, Kerstin; Hoch, Renee; Rubenstein, John L.; Kurniawan, Nyoman D.; Richards, Linda J.

    2010-01-01

    Diffusion magnetic resonance imaging (dMRI) tractography can be employed to simultaneously analyse three-dimensional white matter tracts in the brain. Numerous methods have been proposed to model diffusion-weighted magnetic resonance data for tractography, and we have explored the functionality of some of these for studying white and grey matter pathways in ex vivo mouse brain. Using various deterministic and probabilistic algorithms across a range of regions of interest we found that probabilistic tractography provides a more robust means of visualizing both white and grey matter pathways than deterministic tractography. Importantly, we demonstrate the sensitivity of probabilistic tractography profiles to streamline number, step size, curvature, fiber orientation distribution, and whole-brain versus region of interest seeding. Using anatomically well-defined cortico-thalamic pathways, we show how density maps can permit the topographical assessment of probabilistic tractography. Finally, we show how different tractography approaches can impact on dMRI assessment of tract changes in a mouse deficient for the frontal cortex morphogen, fibroblast growth factor 17. In conclusion, probabilistic tractography can elucidate the phenotypes of mice with neurodegenerative or neurodevelopmental disorders in a quantitative manner. PMID:20303410

  20. Brain size and brain organization of the whale shark, Rhincodon typus, using magnetic resonance imaging.

    Science.gov (United States)

    Yopak, Kara E; Frank, Lawrence R

    2009-01-01

    Very little is known about the brain organization of the suction filter feeder, Rhincodon typus, and how it compares to other orectolobiforms in light of its specialization as a plankton-feeder. Brain size and overall brain organization was assessed in two specimens of R. typus in relation to both phylogeny and ecology, using magnetic resonance imaging (MRI). In comparison to over 60 other chondrichthyan species, R. typus demonstrated a relatively small brain for its body size (expressed in terms of encephalization quotients and residuals), similar to the lamniforms Carcharodon carcharias, Cetorhinus maximus, and Carcharias taurus. R. typus possessed a relatively small telencephalon with some development of the dorsal pallium, which was suggestive of moderate social behavior, in addition to a relatively large diencephalon and a relatively reduced mesencephalon. The most notable characteristic of the brain of Rhincodon was a large and highly foliated cerebellum, one of the largest cerebellums within the chondrichthyan clade. Early development of the brain was qualitatively assessed using an in situ MRI scan of the brain and chondrocranium of a neonate specimen of R. typus. There was evidence that folding of the cerebellar corpus appeared in early development, although the depth and number of folds might vary ontogenetically in this species. Hierarchical cluster analysis and multidimensional scaling ordinations showed evidence of convergent evolution with the basking shark, Cetorhinus maximus, another large-bodied filter feeding elasmobranch, supporting the claim that organization of the brain is more similar in species with analogous but independently evolved lifestyles than those that share taxonomic classification. PMID:19729899

  1. Image characterization by fractal descriptors in variational mode decomposition domain: Application to brain magnetic resonance

    Science.gov (United States)

    Lahmiri, Salim

    2016-08-01

    The main purpose of this work is to explore the usefulness of fractal descriptors estimated in multi-resolution domains to characterize biomedical digital image texture. In this regard, three multi-resolution techniques are considered: the well-known discrete wavelet transform (DWT) and the empirical mode decomposition (EMD), and; the newly introduced; variational mode decomposition mode (VMD). The original image is decomposed by the DWT, EMD, and VMD into different scales. Then, Fourier spectrum based fractal descriptors is estimated at specific scales and directions to characterize the image. The support vector machine (SVM) was used to perform supervised classification. The empirical study was applied to the problem of distinguishing between normal and abnormal brain magnetic resonance images (MRI) affected with Alzheimer disease (AD). Our results demonstrate that fractal descriptors estimated in VMD domain outperform those estimated in DWT and EMD domains; and also those directly estimated from the original image.

  2. Classification of brain tumor extracts by high resolution ¹H MRS using partial least squares discriminant analysis

    Directory of Open Access Journals (Sweden)

    A.V. Faria

    2011-02-01

    Full Text Available High resolution proton nuclear magnetic resonance spectroscopy (¹H MRS can be used to detect biochemical changes in vitro caused by distinct pathologies. It can reveal distinct metabolic profiles of brain tumors although the accurate analysis and classification of different spectra remains a challenge. In this study, the pattern recognition method partial least squares discriminant analysis (PLS-DA was used to classify 11.7 T ¹H MRS spectra of brain tissue extracts from patients with brain tumors into four classes (high-grade neuroglial, low-grade neuroglial, non-neuroglial, and metastasis and a group of control brain tissue. PLS-DA revealed 9 metabolites as the most important in group differentiation: γ-aminobutyric acid, acetoacetate, alanine, creatine, glutamate/glutamine, glycine, myo-inositol, N-acetylaspartate, and choline compounds. Leave-one-out cross-validation showed that PLS-DA was efficient in group characterization. The metabolic patterns detected can be explained on the basis of previous multimodal studies of tumor metabolism and are consistent with neoplastic cell abnormalities possibly related to high turnover, resistance to apoptosis, osmotic stress and tumor tendency to use alternative energetic pathways such as glycolysis and ketogenesis.

  3. Magnetic Nanoparticles Cross the Blood-Brain Barrier: When Physics Rises to a Challenge

    Directory of Open Access Journals (Sweden)

    Maria Antònia Busquets

    2015-12-01

    Full Text Available The blood-brain barrier is a physical and physiological barrier that protects the brain from toxic substances within the bloodstream and helps maintain brain homeostasis. It also represents the main obstacle in the treatment of many diseases of the central nervous system. Among the different approaches employed to overcome this barrier, the use of nanoparticles as a tool to enhance delivery of therapeutic molecules to the brain is particularly promising. There is special interest in the use of magnetic nanoparticles, as their physical characteristics endow them with additional potentially useful properties. Following systemic administration, a magnetic field applied externally can mediate the capacity of magnetic nanoparticles to permeate the blood-brain barrier. Meanwhile, thermal energy released by magnetic nanoparticles under the influence of radiofrequency radiation can modulate blood-brain barrier integrity, increasing its permeability. In this review, we present the strategies that use magnetic nanoparticles, specifically iron oxide nanoparticles, to enhance drug delivery to the brain.

  4. Gadolinium-enhanced magnetic resonance angiography in brain death

    Science.gov (United States)

    Luchtmann, M.; Beuing, O.; Skalej, M.; Kohl, J.; Serowy, S.; Bernarding, J.; Firsching, R.

    2014-01-01

    Confirmatory tests for the diagnosis of brain death in addition to clinical findings may shorten observation time required in some countries and may add certainty to the diagnosis under specific circumstances. The practicability of Gadolinium-enhanced magnetic resonance angiography to confirm cerebral circulatory arrest was assessed after the diagnosis of brain death in 15 patients using a 1.5 Tesla MRI scanner. In all 15 patients extracranial blood flow distal to the external carotid arteries was undisturbed. In 14 patients no contrast medium was noted within intracerebral vessels above the proximal level of the intracerebral arteries. In one patient more distal segments of the anterior and middle cerebral arteries (A3 and M3) were filled with contrast medium. Gadolinium-enhanced MRA may be considered conclusive evidence of cerebral circulatory arrest, when major intracranial vessels fail to fill with contrast medium while extracranial vessels show normal blood flow.

  5. Fluorescent-protein stabilization and high-resolution imaging of cleared, intact mouse brains.

    Directory of Open Access Journals (Sweden)

    Martin K Schwarz

    Full Text Available In order to observe and quantify long-range neuronal connections in intact mouse brain by light microscopy, it is first necessary to clear the brain, thus suppressing refractive-index variations. Here we describe a method that clears the brain and preserves the signal from proteinaceous fluorophores using a pH-adjusted non-aqueous index-matching medium. Successful clearing is enabled through the use of either 1-propanol or tert-butanol during dehydration whilst maintaining a basic pH. We show that high-resolution fluorescence imaging of entire, structurally intact juvenile and adult mouse brains is possible at subcellular resolution, even following many months in clearing solution. We also show that axonal long-range projections that are EGFP-labelled by modified Rabies virus can be imaged throughout the brain using a purpose-built light-sheet fluorescence microscope. To demonstrate the viability of the technique, we determined a detailed map of the monosynaptic projections onto a target cell population in the lateral entorhinal cortex. This example demonstrates that our method permits the quantification of whole-brain connectivity patterns at the subcellular level in the uncut brain.

  6. High-resolution in vivo Wistar rodent brain atlas based on T1 weighted image

    Science.gov (United States)

    Huang, Su; Lu, Zhongkang; Huang, Weimin; Seramani, Sankar; Ramasamy, Boominathan; Sekar, Sakthivel; Guan, Cuntai; Bhakoo, Kishore

    2016-03-01

    Image based atlases for rats brain have a significant impact on pre-clinical research. In this project we acquired T1-weighted images from Wistar rodent brains with fine 59μm isotropical resolution for generation of the atlas template image. By applying post-process procedures using a semi-automatic brain extraction method, we delineated the brain tissues from source data. Furthermore, we applied a symmetric group-wise normalization method to generate an optimized template of T1 image of rodent brain, then aligned our template to the Waxholm Space. In addition, we defined several simple and explicit landmarks to corresponding our template with the well known Paxinos stereotaxic reference system. Anchoring at the origin of the Waxholm Space, we applied piece-wise linear transformation method to map the voxels of the template into the coordinates system in Paxinos' stereotoxic coordinates to facilitate the labelling task. We also cross-referenced our data with both published rodent brain atlas and image atlases available online, methodologically labelling the template to produce a Wistar brain atlas identifying more than 130 structures. Particular attention was paid to the cortex and cerebellum, as these areas encompass the most researched aspects of brain functions. Moreover, we adopted the structure hierarchy and naming nomenclature common to various atlases, so that the names and hierarchy structure presented in the atlas are readily recognised for easy use. It is believed the atlas will present a useful tool in rodent brain functional and pharmaceutical studies.

  7. Anatomical Brain Magnetic Resonance Imaging of Typically Developing Children and Adolescents

    Science.gov (United States)

    Giedd, Jay N.; Lalonde, Francois M.; Celano, Mark J.; White, Samantha L.; Wallace, Gregory L.; Lee, Nancy R.; Lenroot, Rhoshel K.

    2009-01-01

    Methodological issues relevant to magnetic resonance imaging studies of brain anatomy are discussed along with the findings on the neuroanatomic changes during childhood and adolescence. The development of the brain is also discussed.

  8. Three-dimensional structure of brain tissue at submicrometer resolution

    International Nuclear Information System (INIS)

    Biological objects are composed of submicrometer structures such as cells and organelles that are essential for their functions. Here, we report on three-dimensional X-ray visualization of cells and organelles at resolutions up to 100 nm by imaging microtomography (micro-CT) equipped with Fresnel zone plate optics. Human cerebral tissue, fruit fly cephalic ganglia, and Escherichia coli bacteria labeled with high atomic-number elements were embedded in epoxy resin and subjected to X-ray microtomography at the BL37XU and BL47XU beamlines of the SPring-8 synchrotron radiation facility. The obtained results indicated that soft tissue structures can be visualized with the imaging microtomography

  9. Three-dimensional structure of brain tissue at submicrometer resolution

    Energy Technology Data Exchange (ETDEWEB)

    Saiga, Rino; Mizutani, Ryuta, E-mail: ryuta@tokai-u.jp [Department of Applied Biochemistry, Tokai University, Hiratsuka, Kanagawa 259-1292 (Japan); Inomoto, Chie; Takekoshi, Susumu; Nakamura, Naoya; Tsuboi, Akio; Osawa, Motoki [Tokai University School of Medicine, Isehara, Kanagawa 259-1193 (Japan); Arai, Makoto; Oshima, Kenichi; Itokawa, Masanari [Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8506 (Japan); Uesugi, Kentaro; Takeuchi, Akihisa; Terada, Yasuko; Suzuki, Yoshio [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8), Sayo, Hyogo 679-5198 (Japan)

    2016-01-28

    Biological objects are composed of submicrometer structures such as cells and organelles that are essential for their functions. Here, we report on three-dimensional X-ray visualization of cells and organelles at resolutions up to 100 nm by imaging microtomography (micro-CT) equipped with Fresnel zone plate optics. Human cerebral tissue, fruit fly cephalic ganglia, and Escherichia coli bacteria labeled with high atomic-number elements were embedded in epoxy resin and subjected to X-ray microtomography at the BL37XU and BL47XU beamlines of the SPring-8 synchrotron radiation facility. The obtained results indicated that soft tissue structures can be visualized with the imaging microtomography.

  10. 25 T high resolution NMR magnet program and technology

    Energy Technology Data Exchange (ETDEWEB)

    Markiewicz, W.D.; Dixon, I.R.; Eyssa, Y.M.; Schwartz, J.; Swenson, C.A.; Van Sciver, S.; Schneider-Muntau, H.J. [National High Magnetic Field Lab., Tallahassee, FL (United States)

    1996-07-01

    The program at the National High Magnetic Field Laboratory for the design and development of 1 GHz class NMR magnets is described. The parameters are given for a 1.066 GHz magnet incorporating an HTS inner coil. The design of the related wide bore 900 MHz conventional superconductor magnet is described. Aspects of the technology development program supporting these designs are presented.

  11. Functional magnetic resonance imaging of the brain: A quick review

    Directory of Open Access Journals (Sweden)

    Vaghela Viratsinh

    2010-01-01

    Full Text Available Ability to non-invasively map the hemodynamic changes occurring focally in areas of brain involved in various motor, sensory and cognitive functions by functional magnetic resonance imaging (fMRI has revolutionized research in neuroscience in the last two decades. This technique has already gained clinical use especially in pre-surgical evaluation of epilepsy and neurosurgical planning of resection of mass lesions adjacent to eloquent cortex. In this review we attempt to illustrate basic principles and techniques of fMRI, its applications, practical points to consider while performing and evaluating clinical fMRI and its limitations.

  12. Prevalence of abnormal findings on brain magnetic resonance (MR examinations in adult participants of brain docking

    Directory of Open Access Journals (Sweden)

    Taketomi-Takahashi Ayako

    2005-10-01

    Full Text Available Abstract Background To determine the prevalence of abnormal findings on brain magnetic resonance (MR examinations in adult participants of brain docking in order to assess its usefulness. Methods We analyzed screening brain MR examinations for 1113 adults (age, 52.6+/-8.5 years; range, 22–84; 761 male and 352 female performed during 6-year period from April 1998 to March 2004. All participants voluntarily sought a brain MR examination at their own expense. All subjects were studied using the same 1.0-T MR scanner, on axial T1-weighted spin echo (SE images, proton-density-weighted and T2-weighted fast SE images, and intracranial MR angiography (MRA. All abnormal findings were classified into three basic categories: (1 findings with no referral necessary; (2 findings not requiring further evaluation, but which needed to be reported to the referring physician; (3 findings requiring further evaluation. Results Participants with abnormal MR findings requiring further evaluation accounted for 1.3 %, but five of seven suspected intracranial aneurysms were not confirmed by other imaging modalities (false positive. No malignant tumors or other life-threatening pathology was detected, and only three participants (0.27 % with abnormalities underwent surgical treatment. No participant groups were identified from our data as being high risk for MR abnormal findings requiring further evaluation. Conclusion Brain-docking participants had a variety of abnormalities on brain MR examinations, but only a small percentage of these findings required further evaluation. The usefulness of the brain docking with MRI and MRA has yet to be proven, and at this time we cannot approve this screening procedure.

  13. Magnetic resonance imaging research progress on brain functional reorganization after peripheral nerve injury

    International Nuclear Information System (INIS)

    In the recent years, with the development of functional magnetic resonance imaging technology the brain plasticity and functional reorganization are hot topics in the central nervous system imaging studies. Brain functional reorganization and rehabilitation after peripheral nerve injury may have certain regularity. In this paper, the progress of brain functional magnetic resonance imaging technology and its applications in the world wide clinical and experimental researches of the brain functional reorganization after peripheral nerve injury is are reviewed. (authors)

  14. Multivariate Analysis of Magnetic Resonance Imaging Signals of the Human Brain.

    Science.gov (United States)

    Miyawaki, Yoichi

    2016-01-01

    Magnetic resonance imaging (MRI) of the human brain plays an important role in the field of medical imaging as well as basic neuroscience. It measures proton spin relaxation, the time constant of which depends on tissue type, and allows us to visualize anatomical structures in the brain. It can also measure functional signals that depend on the local ratio of oxyhemoglobin to deoxyhemoglobin in the blood, which is believed to reflect the degree of neural activity in the corresponding area. MRI thus provides anatomical and functional information about the human brain with high spatial resolution. Conventionally, MRI signals are measured and analyzed for each individual voxel. However, these signals are essentially multivariate because they are measured from multiple voxels simultaneously, and the pattern of activity might carry more useful information than each individual voxel does. This paper reviews recent trends in multivariate analysis of MRI signals in the human brain, and discusses applications of this technique in the fields of medical imaging and neuroscience.

  15. In vivo interactions of magnetic nanoparticles with the blood-brain barrier

    International Nuclear Information System (INIS)

    Targeted drug delivery to the brain parenchyma, i.e., in brain tumor patients, by means of magnetically supported carrier delivery through the tight vascular endothelium of the blood-brain barrier is of critical biomedical importance. We were interested in delineating the first steps in successful brain drug delivery, which focuses on the interactions between magnetically guided yet freely blood circulating nanoparticles and the blood-brain barrier. We employed an in vivo model to quantitatively determine changes in cerebrovascular flow rate and volume during magnetically guided exposure of circulating nanoparticles.

  16. Improved delineation of short cortical association fibers and gray/white matter boundary using whole-brain three-dimensional diffusion tensor imaging at submillimeter spatial resolution.

    Science.gov (United States)

    Song, Allen W; Chang, Hing-Chiu; Petty, Christopher; Guidon, Arnaud; Chen, Nan-Kuei

    2014-11-01

    Recent emergence of human connectome imaging has led to a high demand on angular and spatial resolutions for diffusion magnetic resonance imaging (MRI). While there have been significant growths in high angular resolution diffusion imaging, the improvement in spatial resolution is still limited due to a number of technical challenges, such as the low signal-to-noise ratio and high motion artifacts. As a result, the benefit of a high spatial resolution in the whole-brain connectome imaging has not been fully evaluated in vivo. In this brief report, the impact of spatial resolution was assessed in a newly acquired whole-brain three-dimensional diffusion tensor imaging data set with an isotropic spatial resolution of 0.85 mm. It was found that the delineation of short cortical association fibers is drastically improved as well as the definition of fiber pathway endings into the gray/white matter boundary-both of which will help construct a more accurate structural map of the human brain connectome.

  17. Base-resolution DNA methylation landscape of zebrafish brain and liver

    Directory of Open Access Journals (Sweden)

    Aniruddha Chatterjee

    2014-12-01

    To our knowledge, these datasets are the only RRBS datasets and base-resolution DNA methylation data available at this time for zebrafish brain and liver. These datasets could serve as a resource for future studies to document the functional role of DNA methylation in zebrafish. In addition, these datasets could be used as controls while performing analysis on treated samples.

  18. Markerless 3D Head Tracking for Motion Correction in High Resolution PET Brain Imaging

    DEFF Research Database (Denmark)

    Olesen, Oline Vinter

    This thesis concerns application specific 3D head tracking. The purpose is to improve motion correction in position emission tomography (PET) brain imaging through development of markerless tracking. Currently, motion correction strategies are based on either the PET data itself or tracking devices...... images. Incorrect motion correction can in the worst cases result in wrong diagnosis or treatment. The evolution of a markerless custom-made structured light 3D surface tracking system is presented. The system is targeted at state-of-the-art high resolution dedicated brain PET scanners with a resolution...... of a few millimeters. Stateof- the-art hardware and software solutions are integrated into an operational device. This novel system is tested against a commercial tracking system popular in PET brain imaging. Testing and demonstrations are carried out in clinical settings. A compact markerless tracking...

  19. Focusing and targeting of magnetic brain stimulation using multiple coils.

    Science.gov (United States)

    Ruohonen, J; Ilmoniemi, R J

    1998-05-01

    Neurones can be excited by an externally applied time-varying electromagnetic field. Focused magnetic brain stimulation is attained using multiple small coils instead of one large coil, the resultant induced electric field being a superposition of the fields from each coil. In multichannel magnetic brain stimulation, partial cancellation of fields from individual coils provides a significant improvement in the focusing of the stimulating field, and independent coil channels allow targeting of the stimuli on a given spot without moving the coils. The problem of shaping the stimulating field in multichannel stimulation is analysed, and a method is derived that yields the driving currents required to induce a field with a user-defined shape. The formulation makes use of lead fields and minimum-norm estimation from magneto-encephalography. Using these methods, some properties of multichannel coil arrays are examined. Computer-assisted multichannel stimulation of the cortex will enable several new studies, including quick determination of the cortical regions, the stimulation of which disrupts cortical processing required by a task. PMID:9747568

  20. Resolution Improvement in Multidimensional Nuclear Magnetic Resonance Spectroscopy of Proteins

    International Nuclear Information System (INIS)

    The work presented in this thesis is concerned with both liquid-state and solid-state nuclear magnetic resonance (NMR) spectroscopy. Most of this work is devoted to the investigation by solid-state NMR of C13-enriched compounds with the principal aim of presenting techniques devised for further improving the spectral resolution in multidimensional NMR of microcrystalline proteins. In fully C13-labelled compounds, the J-coupling induces a broadening of the carbon lineshapes. We show that spin-state-selective technique called IPAP can be successfully combined with standard polarisation transfer schemes in order to remove the J-broadening in multidimensional solid-state NMR correlation experiments of fully C13-enriched proteins. We present subsequently two techniques tailored for liquid-state NMR spectroscopy. The carbon directly detected techniques provide chemical shift information for all backbone hetero-nuclei. They are very attracting for the study of large bio-molecular systems or for the investigation of paramagnetic proteins. In the last part of this thesis, we study the spin-echo J-modulation for homonuclear two-spin 1/2 systems. Under magic-angle spinning, the theory of J-induced spin-echo modulation allows to derive a set of modulation regimes which give a spin-echo modulation exactly equal to the J-coupling. We show that the chemical-shift anisotropy and the dipolar interaction tend to stabilize the spin-echo J-modulation. The theoretical conclusions are supported by numerical simulations and experimental results obtained for three representative samples containing C13 spin pairs. (author)

  1. Viscoelastic properties of the ferret brain measured in vivo at multiple frequencies by magnetic resonance elastography

    OpenAIRE

    Feng, Y.; Clayton, E. H.; Chang, Y.; Okamoto, R.J.; Bayly, P.V.

    2013-01-01

    Characterization of the dynamic mechanical behavior of brain tissue is essential for understanding and simulating the mechanisms of traumatic brain injury (TBI). Changes in mechanical properties may also reflect changes in the brain due to aging or disease. In this study, we used magnetic resonance elastography (MRE) to measure the viscoelastic properties of ferret brain tissue in vivo. Three-dimensional (3D) displacement fields were acquired during wave propagation in the brain induced by ha...

  2. Visible rodent brain-wide networks at single-neuron resolution

    Directory of Open Access Journals (Sweden)

    Jing eYuan

    2015-05-01

    Full Text Available There are some unsolvable fundamental questions, such as cell type classification, neural circuit tracing and neurovascular coupling, though great progresses are being made in neuroscience. Because of the structural features of neurons and neural circuits, the solution of these questions needs us to break through the current technology of neuroanatomy for acquiring the exactly fine morphology of neuron and vessels and tracing long-distant circuit at axonal resolution in the whole brain of mammals. Combined with fast-developing labeling techniques, efficient whole-brain optical imaging technology emerging at the right moment presents a huge potential in the structure and function research of specific-function neuron and neural circuit. In this review, we summarize brain-wide optical tomography techniques, review the progress on visible brain neuronal/vascular networks benefit from these novel techniques, and prospect the future technical development.

  3. Super resolution imaging of genetically labelled synapses in Drosophila brain tissue

    Directory of Open Access Journals (Sweden)

    Isabelle Ayumi Spühler

    2016-05-01

    Full Text Available Understanding synaptic connectivity and plasticity within brain circuits and their relationship to learning and behavior is a fundamental quest in neuroscience. Visualizing the fine details of synapses using optical microscopy remains however a major technical challenge. Super resolution microscopy opens the possibility to reveal molecular features of synapses beyond the diffraction limit. With direct stochastic optical reconstruction microscopy, dSTORM, we image synaptic proteins in the brain tissue of the fruit fly, Drosophila melanogaster. Super resolution imaging of brain tissue harbors difficulties due to light scattering and the density of signals. In order to reduce out of focus signal, we take advantage of the genetic tools available in the Drosophila and have fluorescently tagged synaptic proteins expressed in only a small number of neurons. These neurons form synapses within the calyx of the mushroom body, a distinct brain region involved in associative memory formation. Our results show that super resolution microscopy, in combination with genetically labelled synaptic proteins, is a powerful tool to investigate synapses in a quantitative fashion providing an entry point for studies on synaptic plasticity during learning and memory formation

  4. Robust Intensity Standardization in Brain Magnetic Resonance Images.

    Science.gov (United States)

    De Nunzio, Giorgio; Cataldo, Rosella; Carlà, Alessandra

    2015-12-01

    The paper is focused on a tiSsue-Based Standardization Technique (SBST) of magnetic resonance (MR) brain images. Magnetic Resonance Imaging intensities have no fixed tissue-specific numeric meaning, even within the same MRI protocol, for the same body region, or even for images of the same patient obtained on the same scanner in different moments. This affects postprocessing tasks such as automatic segmentation or unsupervised/supervised classification methods, which strictly depend on the observed image intensities, compromising the accuracy and efficiency of many image analyses algorithms. A large number of MR images from public databases, belonging to healthy people and to patients with different degrees of neurodegenerative pathology, were employed together with synthetic MRIs. Combining both histogram and tissue-specific intensity information, a correspondence is obtained for each tissue across images. The novelty consists of computing three standardizing transformations for the three main brain tissues, for each tissue class separately. In order to create a continuous intensity mapping, spline smoothing of the overall slightly discontinuous piecewise-linear intensity transformation is performed. The robustness of the technique is assessed in a post hoc manner, by verifying that automatic segmentation of images before and after standardization gives a high overlapping (Dice index >0.9) for each tissue class, even across images coming from different sources. Furthermore, SBST efficacy is tested by evaluating if and how much it increases intertissue discrimination and by assessing gaussianity of tissue gray-level distributions before and after standardization. Some quantitative comparisons to already existing different approaches available in the literature are performed.

  5. Brain magnetic resonance findings in infective endocarditis with neurological complications

    International Nuclear Information System (INIS)

    Diagnosing infective endocarditis and its complications can be difficult because of the nonspecific symptoms. We reviewed findings of intracranial abnormalities on magnetic resonance imaging (MRI) in 14 patients with neurological complications and herein discuss the overall intracranial MRI findings. We retrospectively reviewed patients with infective endocarditis from August 2004 to August 2006. Brain MRI, the causative bacteria, and abnormal neurological symptoms were reviewed for 14 patients with neurological complications. Of the 14 patients, 13 showed intracranial abnormalities on MRI. Embolization was seen in 10 patients, hemorrhage in 3, abscess formation in 3, and encephalitis in 2. Hyperintense lesions with a central hypointense area on T2-weighted and/or T2*-weighted imaging (Bull's-eye-like lesion) were seen in four patients. A combination of these intracranial abnormalities was observed in 6 patients. The MRI findings associated with infective endocarditis are wide-ranging: embolization, hemorrhage, meningitis, cerebritis, abscess, the bull's-eye-like lesion. Clinicians should consider the possibility of infective endocarditis in patients with unknown fever and neurological abnormality. Brain MRI should be promptly performed for those patients, and T2*-weighted imaging is recommended for an early diagnosis of infective endocarditis. (author)

  6. On Asymmetry of Magnetic Helicity in Emerging Active Regions: High Resolution Observations

    OpenAIRE

    Tian, Lirong; Démoulin, Pascal; Alexander, David; Zhu, Chunming

    2011-01-01

    We employ the DAVE (differential affine velocity estimator, Schuck 2005; 2006) tracking technique on a time series of MDI/1m high spatial resolution line- of-sight magnetograms to measure the photospheric flow velocity for three newly emerging bipolar active regions. We separately calculate the magnetic helicity injection rate of the leading and following polarities to confirm or refute the magnetic helicity asymmetry, found by Tian & Alexander (2009) using MDI/96m low spatial resolution magn...

  7. The blood-brain barrier penetration and distribution of PEGylated fluorescein-doped magnetic silica nanoparticles in rat brain

    International Nuclear Information System (INIS)

    PEGylated PAMAM conjugated fluorescein-doped magnetic silica nanoparticles (PEGylated PFMSNs) have been synthesized for evaluating their ability across the blood-brain barrier (BBB) and distribution in rat brain. The obtained nanoparticles were characterized by transmission electron microscopy (TEM), thermal gravimetry analyses (TGA), zeta potential (ζ-potential) titration, and X-ray photoelectron spectroscopy (XPS). The BBB penetration and distribution of PEGylated PFMSNs and FMSNs in rat brain were investigated not only at the cellular level with Confocal laser scanning microscopy (CLSM), but also at the subcellular level with transmission electron microscopy (TEM). The results provide direct evidents that PEGylated PFMSNs could penetrate the BBB and spread into the brain parenchyma.

  8. Periodic lateralized epileptiform discharges in neuropsychiatric lupus: association with cerebritis in magnetic resonance imaging and resolution after intravenous immunoglobulin.

    Science.gov (United States)

    Lim, K-S; Cheong, K-L; Tan, C-T

    2010-05-01

    A 13-year-old girl with a known diagnosis of systemic lupus erythematosus presented with seizures and psychosis. An electroencephalogram (EEG) revealed continuous, non-evolving periodic lateralized epileptiform discharges (PLEDs) in the left temporal region, which did not resolve with benzodiazepine. A magnetic resonance imaging (MRI) brain scan demonstrated a focal hyperintensity in the left medial temporal and left occipital lobes, left thalamus and bilateral cerebellar white matter, with evidence of vasculitis in the magnetic resonance angiography. Intravenous immunoglobulin was given because of failed steroid therapy, which resulted in a full resolution of clinical, EEG and MRI abnormalities. Lupus cerebritis should be considered as a possible aetiology in PLEDs, and immunoglobulin can be effective in neuropsychiatric lupus. PMID:20133346

  9. Super resolution imaging of genetically labeled synapses in drosophila brain tissue

    OpenAIRE

    Spühler, Isabelle A.; Conley, Gaurasundar M.; Scheffold, Frank; Sprecher, Simon G.

    2016-01-01

    Understanding synaptic connectivity and plasticity within brain circuits and their relationship to learning and behavior is a fundamental quest in neuroscience. Visualizing the fine details of synapses using optical microscopy remains however a major technical challenge. Super resolution microscopy opens the possibility to reveal molecular features of synapses beyond the diffraction limit. With direct stochastic optical reconstruction microscopy, dSTORM, we image synaptic proteins in the...

  10. High resolution paraventricular nucleus serial section model constructed within a traditional rat brain atlas

    OpenAIRE

    Simmons, Donna M.; Larry W Swanson

    2008-01-01

    As a starting point for constructing a high resolution, resliceable computer graphics model for the extraction, quantitative analysis, display, and modeling of neuroanatomical data the outer border and the boundaries of inner divisions and parts of the paraventricular nucleus have been drawn for all 39 serial histological sections prepared for a published reference atlas of the rat brain. This careful parceling revealed three new features of paraventricular nucleus topography: the full rostra...

  11. High Resolution Mapping of Modafinil Induced Changes in Glutamate Level in Rat Brain

    OpenAIRE

    Haris, Mohammad; Singh, Anup; Cai, Kejia; Nath, Kavindra; Verma, Gaurav; Nanga, Ravi Prakash Reddy; Hariharan, Hari; Detre, John A.; Epperson, Neill; Reddy, Ravinder

    2014-01-01

    Modafinil is marketed in the United States for the treatment of narcolepsy and daytime somnolence due to shift-work or sleep apnea. Investigations of this drug in the treatment of cocaine and nicotine dependence in addition to disorders of executive function are also underway. Modafinil has been known to increase glutamate levels in rat brain models. Proton magnetic resonance spectroscopy (1HMRS) has been commonly used to detect the glutamate (Glu) changes in vivo. In this study, we used a re...

  12. High-resolution x-ray absorption spectroscopy studies of metal compounds in neurodegenerative brain tissue

    Energy Technology Data Exchange (ETDEWEB)

    Collingwood, J.F.; Mikhaylova, A.; Davidson, M.R.; Batich, C.; Streit, W.J.; Eskin, T.; Terry, J.; Barrea, R.; Underhill, R.S.; Dobson, J. (IIT); (Keele); (Florida); (DRDC)

    2008-06-16

    Fluorescence mapping and microfocus X-ray absorption spectroscopy are used to detect, locate and identify iron biominerals and other inorganic metal accumulations in neurodegenerative brain tissue at sub-cellular resolution (< 5 microns). Recent progress in developing the technique is reviewed. Synchrotron X-rays are used to map tissue sections for metals of interest, and XANES and XAFS are used to characterize anomalous concentrations of the metals in-situ so that they can be correlated with tissue structures and disease pathology. Iron anomalies associated with biogenic magnetite, ferritin and haemoglobin are located and identified in an avian tissue model with a pixel resolution {approx} 5 microns. Subsequent studies include brain tissue sections from transgenic Huntington's mice, and the first high-resolution mapping and identification of iron biominerals in human Alzheimer's and control autopsy brain tissue. Technical developments include use of microfocus diffraction to obtain structural information about biominerals in-situ, and depositing sample location grids by lithography for the location of anomalies by conventional microscopy. The combined techniques provide a breakthrough in the study of both intra- and extra-cellular iron compounds and related metals in tissue. The information to be gained from this approach has implications for future diagnosis and treatment of neurodegeneration, and for our understanding of the mechanisms involved.

  13. A Magnetic Resonance Image Based Atlas of the Rabbit Brain for Automatic Parcellation

    OpenAIRE

    Emma Muñoz-Moreno; Ariadna Arbat-Plana; Dafnis Batalle; Guadalupe Soria; Miriam Illa; Alberto Prats-Galino; Elisenda Eixarch; Eduard Gratacos

    2013-01-01

    Rabbit brain has been used in several works for the analysis of neurodevelopment. However, there are not specific digital rabbit brain atlases that allow an automatic identification of brain regions, which is a crucial step for various neuroimage analyses, and, instead, manual delineation of areas of interest must be performed in order to evaluate a specific structure. For this reason, we propose an atlas of the rabbit brain based on magnetic resonance imaging, including both structural and d...

  14. Electron beam fabrication and characterization of high- resolution magnetic force microscopy tips

    NARCIS (Netherlands)

    Rührig, M.; Porthun, S.; Lodder, J.C.; McVitie, S.; Heyderman, L.J.; Johnston, A.B.; Chapman, J.N.

    1996-01-01

    The stray field, magnetic microstructure, and switching behavior of high‐resolution electron beam fabricated thin film tips for magnetic force microscopy (MFM) are investigated with different imaging modes in a transmission electron microscope (TEM). As the tiny smooth carbon needles covered with a

  15. Neuroimaging of pediatric brain tumors: from basic to advanced magnetic resonance imaging (MRI).

    Science.gov (United States)

    Panigrahy, Ashok; Blüml, Stefan

    2009-11-01

    In this review, the basic magnetic resonance concepts used in the imaging approach of a pediatric brain tumor are described with respect to different factors including understanding the significance of the patient's age. Also discussed are other factors directly related to the magnetic resonance scan itself including evaluating the location of the tumor, determining if the lesion is extra-axial or intra-axial, and evaluating the contrast characteristics of the lesion. Of note, there are key imaging features of pediatric brain tumors, which can give information about the cellularity of the lesion, which can then be confirmed with advanced magnetic resonance imaging (MRI) techniques. The second part of this review will provide an overview of the major advanced MRI techniques used in pediatric imaging, particularly, magnetic resonance diffusion, magnetic resonance spectroscopy, and magnetic resonance perfusion. The last part of the review will provide more specific information about the use of advanced magnetic resonance techniques in the evaluation of pediatric brain tumors.

  16. Differential aquaporin 4 expression during edema build-up and resolution phases of brain inflammation

    Directory of Open Access Journals (Sweden)

    Brochet Bruno

    2011-10-01

    Full Text Available Abstract Background Vasogenic edema dynamically accumulates in many brain disorders associated with brain inflammation, with the critical step of edema exacerbation feared in patient care. Water entrance through blood-brain barrier (BBB opening is thought to have a role in edema formation. Nevertheless, the mechanisms of edema resolution remain poorly understood. Because the water channel aquaporin 4 (AQP4 provides an important route for vasogenic edema resolution, we studied the time course of AQP4 expression to better understand its potential effect in countering the exacerbation of vasogenic edema. Methods Focal inflammation was induced in the rat brain by a lysolecithin injection and was evaluated at 1, 3, 7, 14 and 20 days using a combination of in vivo MRI with apparent diffusion coefficient (ADC measurements used as a marker of water content, and molecular and histological approaches for the quantification of AQP4 expression. Markers of active inflammation (macrophages, BBB permeability, and interleukin-1β and markers of scarring (gliosis were also quantified. Results This animal model of brain inflammation demonstrated two phases of edema development: an initial edema build-up phase during active inflammation that peaked after 3 days (ADC increase was followed by an edema resolution phase that lasted from 7 to 20 days post injection (ADC decrease and was accompanied by glial scar formation. A moderate upregulation in AQP4 was observed during the build-up phase, but a much stronger transcriptional and translational level of AQP4 expression was observed during the secondary edema resolution phase. Conclusions We conclude that a time lag in AQP4 expression occurs such that the more significant upregulation was achieved only after a delay period. This change in AQP4 expression appears to act as an important determinant in the exacerbation of edema, considering that AQP4 expression is insufficient to counter the water influx during the build

  17. High-Resolution and Quantitative X-Ray Phase-Contrast Tomography for Mouse Brain Research

    Directory of Open Access Journals (Sweden)

    Yan Xi

    2015-01-01

    Full Text Available Imaging techniques for visualizing cerebral vasculature and distinguishing functional areas are essential and critical to the study of various brain diseases. In this paper, with the X-ray phase-contrast imaging technique, we proposed an experiment scheme for the ex vivo mouse brain study, achieving both high spatial resolution and improved soft-tissue contrast. This scheme includes two steps: sample preparation and volume reconstruction. In the first step, we use heparinized saline to displace the blood inside cerebral vessels and then replace it with air making air-filled mouse brain. After sample preparation, X-ray phase-contrast tomography is performed to collect the data for volume reconstruction. Here, we adopt a phase-retrieval combined filtered backprojection method to reconstruct its three-dimensional structure and redesigned the reconstruction kernel. To evaluate its performance, we carried out experiments at Shanghai Synchrotron Radiation Facility. The results show that the air-tissue structured cerebral vasculatures are highly visible with propagation-based phase-contrast imaging and can be clearly resolved in reconstructed cross-images. Besides, functional areas, such as the corpus callosum, corpus striatum, and nuclei, are also clearly resolved. The proposed method is comparable with hematoxylin and eosin staining method but represents the studied mouse brain in three dimensions, offering a potential powerful tool for the research of brain disorders.

  18. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    Science.gov (United States)

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks.

  19. High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

    Directory of Open Access Journals (Sweden)

    Jacob Sharvit

    2007-09-01

    Full Text Available The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primarypurpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960.A magnetic map of the survey area (3.5 km2 on a 0.5 m grid was created revealing theanomalies at sub-meter accuracy. For each investigated target location a correspondingferro-metallic item was dug out, one of which turned to be very similar to a part of thecrashed airplane. The accuracy of location was confirmed by matching the position of theactual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m.

  20. An electric field induced in the retina and brain at threshold magnetic flux density causing magnetophosphenes.

    Science.gov (United States)

    Hirata, Akimasa; Takano, Yukinori; Fujiwara, Osamu; Dovan, Thanh; Kavet, Robert

    2011-07-01

    For magnetic field exposures at extremely low frequencies, the electrostimulatory response with the lowest threshold is the magnetophosphene, a response that corresponds to an adult exposed to a 20 Hz magnetic field of nominally 8.14 mT. In the IEEE standard C95.6 (2002), the corresponding in situ field in the retinal locus of an adult-sized ellipsoidal was calculated to be 53 mV m(-1). However, the associated dose in the retina and brain at a high level of resolution in anatomically correct human models is incompletely characterized. Furthermore, the dose maxima in tissue computed with voxel human models are prone to staircasing errors, particularly for the low-frequency dosimetry. In the analyses presented in this paper, analytical and quasi-static finite-difference time-domain (FDTD) solutions were first compared for a three-layer sphere exposed to a uniform 50 Hz magnetic field. Staircasing errors in the FDTD results were observed at the tissue interface, and were greatest at the skin-air boundary. The 99th percentile value was within 3% of the analytic maximum, depending on model resolution, and thus may be considered a close approximation of the analytic maximum. For the adult anatomical model, TARO, exposed to a uniform magnetic field, the differences in the 99th percentile value of in situ electric fields for 2 mm and 1 mm voxel models were at most several per cent. For various human models exposed at the magnetophosphene threshold at three orthogonal field orientations, the in situ electric field in the brain was between 10% and 70% greater than the analytical IEEE threshold of 53 mV m(-1), and in the retina was lower by roughly 50% for two horizontal orientations (anterior-posterior and lateral), and greater by about 15% for a vertically oriented field. Considering a reduction factor or safety factors of several folds applied to electrostimulatory thresholds, the 99th percentile dose to a tissue calculated with voxel human models may be used as an

  1. Simulation study of magnetic resonance imaging-guided cortically constrained diffuse optical tomography of human brain function.

    Science.gov (United States)

    Boas, David A; Dale, Anders M

    2005-04-01

    Diffuse optical imaging can measure brain activity noninvasively in humans through the scalp and skull by measuring the light intensity modulation arising from localized-activity-induced absorption changes within the cortex. Spatial resolution and localization accuracy are currently limited by measurement geometry to approximately 3 cm in the plane parallel to the scalp. Depth resolution is a more significant challenge owing to the limited angle tomography permitted by reflectance-only measurements. We combine previously established concepts for improving image quality and demonstrate, through simulation studies, their application for improving the image quality of adult human brain function. We show in a three-dimensional human head model that localization accuracy is significantly improved by the addition of measurements that provide overlapping samples of brain tissue. However, the reconstructed absorption contrast is significantly underestimated because its depth is underestimated. We show that the absorption contrast amplitude accuracy can be significantly improved by providing a cortical spatial constraint in the image reconstruction to obtain a better depth localization. The cortical constraint makes physiological sense since the brain-activity-induced absorption changes are occurring in the cortex and not in the scalp, skull, and cerebral spinal fluid. This spatial constraint is provided by segmentation of coregistered structural magnetic resonance imaging (MRI). However, the absorption contrast deep within the cortex is reconstructed superficially, resulting in an underestimation of the absorption contrast. The synthesis of techniques described here indicates that multimodality imaging of brain function with diffuse optical imaging and MRI has the potential to provide more quantitative estimates of the total and deoxyhemoglobin response to brain activation, which is currently not provided by either method independently. However, issues of depth resolution

  2. Simulation study of magnetic resonance imaging-guided cortically constrained diffuse optical tomography of human brain function

    Science.gov (United States)

    Boas, David A.; Dale, Anders M.

    2005-04-01

    Diffuse optical imaging can measure brain activity noninvasively in humans through the scalp and skull by measuring the light intensity modulation arising from localized-activity-induced absorption changes within the cortex. Spatial resolution and localization accuracy are currently limited by measurement geometry to approximately 3 cm in the plane parallel to the scalp. Depth resolution is a more significant challenge owing to the limited angle tomography permitted by reflectance-only measurements. We combine previously established concepts for improving image quality and demonstrate, through simulation studies, their application for improving the image quality of adult human brain function. We show in a three-dimensional human head model that localization accuracy is significantly improved by the addition of measurements that provide overlapping samples of brain tissue. However, the reconstructed absorption contrast is significantly underestimated because its depth is underestimated. We show that the absorption contrast amplitude accuracy can be significantly improved by providing a cortical spatial constraint in the image reconstruction to obtain a better depth localization. The cortical constraint makes physiological sense since the brain-activity-induced absorption changes are occurring in the cortex and not in the scalp, skull, and cerebral spinal fluid. This spatial constraint is provided by segmentation of coregistered structural magnetic resonance imaging (MRI). However, the absorption contrast deep within the cortex is reconstructed superficially, resulting in an underestimation of the absorption contrast. The synthesis of techniques described here indicates that multimodality imaging of brain function with diffuse optical imaging and MRI has the potential to provide more quantitative estimates of the total and deoxyhemoglobin response to brain activation, which is currently not provided by either method independently. However, issues of depth resolution

  3. Grid Computing Application for Brain Magnetic Resonance Image Processing

    International Nuclear Information System (INIS)

    This work emphasizes the use of grid computing and web technology for automatic post-processing of brain magnetic resonance images (MRI) in the context of neuropsychiatric (Alzheimer's disease) research. Post-acquisition image processing is achieved through the interconnection of several individual processes into pipelines. Each process has input and output data ports, options and execution parameters, and performs single tasks such as: a) extracting individual image attributes (e.g. dimensions, orientation, center of mass), b) performing image transformations (e.g. scaling, rotation, skewing, intensity standardization, linear and non-linear registration), c) performing image statistical analyses, and d) producing the necessary quality control images and/or files for user review. The pipelines are built to perform specific sequences of tasks on the alphanumeric data and MRIs contained in our database. The web application is coded in PHP and allows the creation of scripts to create, store and execute pipelines and their instances either on our local cluster or on high-performance computing platforms. To run an instance on an external cluster, the web application opens a communication tunnel through which it copies the necessary files, submits the execution commands and collects the results. We present result on system tests for the processing of a set of 821 brain MRIs from the Alzheimer's Disease Neuroimaging Initiative study via a nonlinear registration pipeline composed of 10 processes. Our results show successful execution on both local and external clusters, and a 4-fold increase in performance if using the external cluster. However, the latter's performance does not scale linearly as queue waiting times and execution overhead increase with the number of tasks to be executed.

  4. Brain Magnetic Resonance Imaging After High-Dose Chemotherapy and Radiotherapy for Childhood Brain Tumors

    International Nuclear Information System (INIS)

    Purpose: Brain necrosis or other subacute iatrogenic reactions has been recognized as a potential complication of radiotherapy (RT), although the possible synergistic effects of high-dose chemotherapy and RT might have been underestimated. Methods and Materials: We reviewed the clinical and radiologic data of 49 consecutive children with malignant brain tumors treated with high-dose thiotepa and autologous hematopoietic stem cell rescue, preceded or followed by RT. The patients were assessed for neurocognitive tests to identify any correlation with magnetic resonance imaging (MRI) anomalies. Results: Of the 49 children, 18 (6 of 25 with high-grade gliomas and 12 of 24 with primitive neuroectodermal tumors) had abnormal brain MRI findings occurring a median of 8 months (range, 2-39 months) after RT and beginning to regress a median of 13 months (range, 2-26 months) after onset. The most common lesion pattern involved multiple pseudonodular, millimeter-size, T1-weighted unevenly enhancing, and T2-weighted hyperintense foci. Four patients with primitive neuroectodermal tumors also had subdural fluid leaks, with meningeal enhancement over the effusion. One-half of the patients had symptoms relating to the new radiographic findings. The MRI lesion-free survival rate was 74% ± 6% at 1 year and 57% ± 8% at 2 years. The number of marrow ablative courses correlated significantly to the incidence of radiographic anomalies. No significant difference was found in intelligent quotient scores between children with and without radiographic changes. Conclusion: Multiple enhancing cerebral lesions were frequently seen on MRI scans soon after high-dose chemotherapy and RT. Such findings pose a major diagnostic challenge in terms of their differential diagnosis vis-a-vis recurrent tumor. Their correlation with neurocognitive results deserves further investigation

  5. Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

    Institute of Scientific and Technical Information of China (English)

    Quan Jiang

    2016-01-01

    Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance im-aging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

  6. Magnetic resonance imaging and cell-based neurorestorative therapy after brain injury

    Directory of Open Access Journals (Sweden)

    Quan Jiang

    2016-01-01

    Full Text Available Restorative cell-based therapies for experimental brain injury, such as stroke and traumatic brain injury, substantially improve functional outcome. We discuss and review state of the art magnetic resonance imaging methodologies and their applications related to cell-based treatment after brain injury. We focus on the potential of magnetic resonance imaging technique and its associated challenges to obtain useful new information related to cell migration, distribution, and quantitation, as well as vascular and neuronal remodeling in response to cell-based therapy after brain injury. The noninvasive nature of imaging might more readily help with translation of cell-based therapy from the laboratory to the clinic.

  7. Magnetic resonance monitoring of focused ultrasound/magnetic nanoparticle targeting delivery of therapeutic agents to the brain

    OpenAIRE

    Liu, Hao-Li; Hua, Mu-Yi; Yang, Hung-Wei; Huang, Chiung-Yin; Chu, Po-Chun; Wu, Jia-Shin; Tseng, I-Chou; Wang, Jiun-Jie; Yen, Tzu-Chen; Chen, Pin-Yuan; Wei, Kuo-Chen

    2010-01-01

    The superparamagnetic properties of magnetic nanoparticles (MNPs) allow them to be guided by an externally positioned magnet and also provide contrast for MRI. However, their therapeutic use in treating CNS pathologies in vivo is limited by insufficient local accumulation and retention resulting from their inability to traverse biological barriers. The combined use of focused ultrasound and magnetic targeting synergistically delivers therapeutic MNPs across the blood–brain barrier to enter th...

  8. Triangulating the sexually dimorphic brain through high-resolution neuroimaging of murine sex chromosome aneuploidies.

    Science.gov (United States)

    Raznahan, Armin; Lue, YanHe; Probst, Frank; Greenstein, Deanna; Giedd, Jay; Wang, Christina; Lerch, Jason; Swerdloff, Ronald

    2015-11-01

    Murine sex chromosome aneuploidies (SCAs) provide powerful models for charting sex chromosome influences on mammalian brain development. Here, building on prior work in X-monosomic (XO) mice, we use spatially non-biased high-resolution imaging to compare and contrast neuroanatomical alterations in XXY and XO mice relative to their wild-type XX and XY littermates. First, we show that carriage of a supernumerary X chromosome in XXY males (1) does not prevent normative volumetric masculinization of the bed nucleus of the stria terminalis (BNST) and medial amygdala, but (2) causes distributed anatomical alterations relative to XY males, which show a statistically unexpected tendency to be co-localized with and reciprocal to XO-XX differences in anatomy. These overlaps identify the lateral septum, BNST, ventral group thalamic nuclei and periaqueductal gray matter as regions with replicable sensitivity to X chromosome dose across two SCAs. We then harness anatomical variation across all four karyotype groups in our study--XO, XX, XY and XXY--to create an agnostic data-driven segmentation of the mouse brain into five distributed clusters which (1) recover fundamental properties of brain organization with high spatial precision, (2) define two previously uncharacterized systems of relative volume excess in females vs. males ("forebrain cholinergic" and "cerebelo-pontine-thalamo-cortical"), and (3) adopt stereotyped spatial motifs which delineate ordered gradients of sex chromosome and gonadal influences on volumetric brain development. Taken together, these data provide a new framework for the study of sexually dimorphic influences on brain development in health and disrupted brain development in SCA.

  9. Low resolution brain electromagnetic tomography in a realistic geometry head model: a simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Ding Lei; Lai Yuan; He Bin [Department of Biomedical Engineering, University of Minnesota, 7-105 BSBE, 312 Church Street SE, Minneapolis, MN 55455 (United States)

    2005-01-07

    It is of importance to localize neural sources from scalp recorded EEG. Low resolution brain electromagnetic tomography (LORETA) has received considerable attention for localizing brain electrical sources. However, most such efforts have used spherical head models in representing the head volume conductor. Investigation of the performance of LORETA in a realistic geometry head model, as compared with the spherical model, will provide useful information guiding interpretation of data obtained by using the spherical head model. The performance of LORETA was evaluated by means of computer simulations. The boundary element method was used to solve the forward problem. A three-shell realistic geometry (RG) head model was constructed from MRI scans of a human subject. Dipole source configurations of a single dipole located at different regions of the brain with varying depth were used to assess the performance of LORETA in different regions of the brain. A three-sphere head model was also used to approximate the RG head model, and similar simulations performed, and results compared with the RG-LORETA with reference to the locations of the simulated sources. Multi-source localizations were discussed and examples given in the RG head model. Localization errors employing the spherical LORETA, with reference to the source locations within the realistic geometry head, were about 20-30 mm, for four brain regions evaluated: frontal, parietal, temporal and occipital regions. Localization errors employing the RG head model were about 10 mm over the same four brain regions. The present simulation results suggest that the use of the RG head model reduces the localization error of LORETA, and that the RG head model based LORETA is desirable if high localization accuracy is needed.

  10. Magnetic resonance imaging of the brain in patients with migraine

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, H.; Sakai, F.; Kan, S.; Okada, J.; Tazaki, Y. (Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine)

    1991-05-01

    Magnetic resonance imaging (MRI) was studied in 91 patients with migraine and in 98 controls. Risk factors known to cause MRI lesions were carefully examined. In 36 patients with migraine (39.6%), small foci of high intensity on T{sub 2}-weighted and proton-density-weighted images were seen in the white matter. Of patients with migraine who were less than 40 years old and without any risk factor, 29.4% showed lesions on MRI; this was singificantly higher than the 11.2% for the group of age-matched controls (n=98). The lesions were distributed predominantly in the centrum semiovale and frontal white matter in young patients, but extended to the deeper white matter at the level of basal ganglia in the older age group. The side of the MRI lesions did not always correspond to the side of usual aura or headache. Migraine-related variables such as type of migraine, frequency, duration or intensity of headache or consumption of ergotamine showed no significant correlation with the incidence om MRI abnormalities. The data indicated that migraine may be associated with early pathologic changes in the brain. 26 refs., 4 figs., 3 tabs.

  11. Clinical application of magnetic resonance in acute traumatic brain injury

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Dionei F.; Gaia, Felipe F.P. [Hospital de Base de Sao Jose do Rio Preto, SP (Brazil). Servico de Neurocirurgia]. E-mail: centro@cerebroecoluna.com.br; Spotti, Antonio R.; Tognola, Waldir A. [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Dept. de Ciencias Neurologicas; Andrade, Almir F. [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Dept. de Neurocirurgia da Emergencia

    2008-07-01

    Purpose: To evaluate the clinical applications of magnetic resonance imaging (MRI) in patients with acute traumatic brain injury (TBI): to identify the type, quantity, severity; and improvement clinical-radiological correlation. Method: Assessment of 55 patients who were imaged using CT and MRI, 34 (61.8%) males and 21 (38.2%) females, with acute (0 to 5 days) and closed TBI. Results: Statistical significant differences (McNemar test): occurred fractures were detected by CT in 29.1% and by MRI in 3.6% of the patients; subdural hematoma by CT in 10.9% and MRI in 36.4 %; diffuse axonal injury (DAI) by CT in 1.8% and MRI in 50.9%; cortical contusions by CT in 9.1% and MRI in 41.8%; subarachnoid hemorrhage by CT in 18.2% and MRI in 41.8%. Conclusion: MRI was superior to the CT in the identification of DAI, subarachnoid hemorrhage, cortical contusions, and acute subdural hematoma; however it was inferior in diagnosing fractures. The detection of DAI was associated with the severity of acute TBI. (author)

  12. Advances in high-resolution nuclear magnetic resonance methods in inhomogeneous magnetic fields using intermolecular multiple quantum coherences

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Strong and extremely homogeneous static magnetic field is usually required for high-resolution nu-clear magnetic resonance (NMR). However, in the cases of in vivo and so on, the magnetic field inho-mogeneity owing to magnetic susceptibility variation in samples is unavoidable and hard to eliminate by conventional methods such as shimming. Recently, intermolecular multiple quantum coherences (iMQCs) have been employed to eliminate inhomogeneous broadening and obtain high-resolution NMR spectra, especially for in vivo samples. Compared to other high-resolution NMR methods, iMQC method exhibits its unique feature and advantage. It simultaneously holds information of chemical shifts, multiplet structures, coupling constants, and relative peak areas. All the information is often used to analyze and characterize molecular structures in conventional one-dimensional NMR spec-troscopy. In this work, recent technical developments including our results in this field are summarized; the high-resolution mechanism is analyzed and comparison with other methods based on interactions between spins is made; comments on the current situation and outlook on the research directions are also made.

  13. Ultra-high resolution polarization-sensitive optical coherence microscopy for brain imaging at 6 um, 3.4 um and 1.3 um resolution (Conference Presentation)

    Science.gov (United States)

    Wang, Hui; Akkin, Taner; Magnain, Caroline V.; Yaseen, Mohammad A.; Cramer, Avilash; Wang, Ruopeng; Sakadžic, Sava; Boas, David A.

    2016-03-01

    Neuroanatomical pathways form the basis for functional activity of brain circuits. In the past, we developed a polarization-sensitive optical coherence tomography with serial scanning to achieve large-scale brain imaging. The system was able to visualize 3D fiber tracts of ~20 um in diameter. To investigate the neuroanatomical pathways at finer scales, we have now built a polarization-maintaining fiber based ultra-high resolution polarization-sensitive optical coherence microscope (PS-OCM) at 1300 nm. The PS-OCM has an axial resolution of 3.5 um in tissue. The detection setup consists of two spectrometers, acquiring spectral interference on orthogonal polarization channels. With a single measurement, the setup generates four contrasts: reflectivity, cross-polarization, retardance and optic axis orientation. To investigate the capability of PS-OCM at different resolutions, we used three microscope objectives that yield lateral resolutions of 6.0 um, 3.4 um and 1.3 um. Blocks of formalin fixed mouse brain and human brain were scanned. The cross-polarization and retardance images clearly depict the neuronal fiber structures, which are comparable with that generated by the maximum projection of volumetric reflectivity data. The optic axis orientation quantifies the in-plane fiber orientation. With the lateral resolution of 1.3 um, the retardance contrast is weak in white matter due to the shallow depth of focus. Overall, the ultra-high resolution PS-OCM provides a new tool to reveal neuroanatomical maps in the brain at cellular resolution.

  14. Brain functional magnetic resonance imaging response to glucose and fructose infusions in humans

    Science.gov (United States)

    Objective: In animals, intracerebroventricular glucose and fructose have opposing effects on appetite and weight regulation. In humans, functional brain magnetic resonance imaging (fMRI) studies during carbohydrate ingestion suggest that glucose may regulate HT signaling but are potentially confoun...

  15. Optimal Magnetic Field for Crossing Super-Para-Magnetic Nanoparticles through the Brain Blood Barrier: A Computational Approach

    Directory of Open Access Journals (Sweden)

    Maysam Z. Pedram

    2016-06-01

    Full Text Available This paper scrutinizes the magnetic field effect to deliver the superparamagnetic nanoparticles (SPMNs through the Blood Brain Barrier (BBB. Herein we study the interaction between the nanoparticle (NP and BBB membrane using Molecular Dynamic (MD techniques. The MD model is used to enhance our understanding of the dynamic behavior of SPMNs crossing the endothelial cells in the presence of a gradient magnetic field. Actuation of NPs under weak magnetic field offers the great advantage of a non-invasive drug delivery without the risk of causing injury to the brain. Furthermore, a weak magnetic portable stimulator can be developed using low complexity prototyping techniques. Based on MD simulation results in this paper, SPMNs can cross the cell membrane while experiencing very weak mechanical forces in the range of pN. This study also derives guidelines for the design of the SPMNs dedicated to crossing the BBB using external magnetic fields.

  16. An alternative 3D inversion method for magnetic anomalies with depth resolution

    Directory of Open Access Journals (Sweden)

    M. Chiappini

    2006-06-01

    Full Text Available This paper presents a new method to invert magnetic anomaly data in a variety of non-complex contexts when a priori information about the sources is not available. The region containing magnetic sources is discretized into a set of homogeneously magnetized rectangular prisms, polarized along a common direction. The magnetization distribution is calculated by solving an underdetermined linear system, and is accomplished through the simultaneous minimization of the norm of the solution and the misfit between the observed and the calculated field. Our algorithm makes use of a dipolar approximation to compute the magnetic field of the rectangular blocks. We show how this approximation, in conjunction with other correction factors, presents numerous advantages in terms of computing speed and depth resolution, and does not affect significantly the success of the inversion. The algorithm is tested on both synthetic and real magnetic datasets.

  17. Admission criteria to the Danish Brain Cancer Program are moderately associated with magnetic resonance imaging findings

    DEFF Research Database (Denmark)

    Hill, Thomas Winther; Nielsen, Mie Kiszka; Nepper-Rasmussen, Jørgen

    2013-01-01

    The objective of this study was to evaluate the Danish Brain Cancer Program by examining the criteria for admission to the program and the results of magnetic resonance imaging (MRI) of the brain in 359 patients referred to the program at the Odense University Hospital during one year...

  18. High-resolution dichroic imaging of magnetic flux distributions in superconductors with scanning x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ruoß, S., E-mail: ruoss@is.mpg.de; Stahl, C.; Weigand, M.; Schütz, G. [MPI for Intelligent Systems, Heisenbergstr. 3, D-70569 Stuttgart (Germany); Albrecht, J. [Research Institute for Innovative Surfaces, FINO, Aalen University, Beethovenstr. 1, D-73430 Aalen (Germany)

    2015-01-12

    The penetration of magnetic flux into high-temperature superconductors has been observed using a high-resolution technique based on x-ray magnetic circular dichroism. Superconductors coated with thin soft-magnetic layers are observed in a scanning x-ray microscope under the influence of external magnetic fields. Resulting electric currents in the superconductor create an inhomogeneous magnetic field distribution above the superconductor and lead to a local reorientation of the ferromagnetic layer. Measuring the local magnetization of the ferromagnet by x-ray absorption microscopy with circular-polarized radiation allows the analysis of the magnetic flux distribution in the superconductor with a spatial resolution on the nanoscale.

  19. Multiclass imbalance learning:Improving classification of pediatric brain tumors from magnetic resonance spectroscopy

    OpenAIRE

    Zarinabad, Niloufar; Wilson, Martin P; Gill, Simrandip K.; Manias, Karen A; Davies, Nigel P; Peet, Andrew C

    2016-01-01

    PURPOSE: Classification of pediatric brain tumors from (1) H-magnetic resonance spectroscopy (MRS) can aid diagnosis and management of brain tumors. However, varied incidence of the different tumor types leads to imbalanced class sizes and introduces difficulties in classifying rare tumor groups. This study assessed different imbalanced multiclass learning techniques and compared the use of complete spectra and quantified metabolite profiles for classification of three main childhood brain tu...

  20. Change in brain magnetic resonance spectroscopy after treatment during acute HIV infection.

    Directory of Open Access Journals (Sweden)

    Napapon Sailasuta

    Full Text Available OBJECTIVE: Single voxel proton magnetic resonance spectroscopy (MRS can be used to monitor changes in brain inflammation and neuronal integrity associated with HIV infection and its treatments. We used MRS to measure brain changes during the first weeks following HIV infection and in response to antiretroviral therapy (ART. METHODS: Brain metabolite levels of N-acetyl aspartate (NAA, choline (tCHO, creatine (CR, myoinositol (MI, and glutamate and glutamine (GLX were measured in acute HIV subjects (n = 31 and compared to chronic HIV+individuals (n = 26 and HIV negative control subjects (n = 10 from Bangkok, Thailand. Metabolites were measured in frontal gray matter (FGM, frontal white matter (FWM, occipital gray matter (OGM, and basal ganglia (BG. Repeat measures were obtained in 17 acute subjects 1, 3 and 6 months following initiation of ART. RESULTS: After adjustment for age we identified elevated BG tCHO/CR in acute HIV cases at baseline (median 14 days after HIV infection compared to control (p = 0.0014, as well as chronic subjects (p = 0.0023. A similar tCHO/CR elevation was noted in OGM; no other metabolite abnormalities were seen between acute and control subjects. Mixed longitudinal models revealed resolution of BG tCHO/CR elevation after ART (p = 0.022 with tCHO/CR similar to control subjects at 6 months. INTERPRETATION: We detected cellular inflammation in the absence of measurable neuronal injury within the first month of HIV infection, and normalization of this inflammation following acutely administered ART. Our findings suggest that early ART may be neuroprotective in HIV infection by mitigating processes leading to CNS injury.

  1. Development of a high resolution alpha spectrometer using a magnetic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, W.S. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Korea University of Science and Technology (UST), Daejeon 305-350 (Korea, Republic of); Kang, C.S. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Kim, S.R., E-mail: yhkim@kriss.re.kr [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Kim, G.B. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Lee, H.J. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Lee, M.K.; Lee, J.H. [Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); So, J.H. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Kim, Y.H. [Center for Underground Physics, Institute for Basic Science (IBS), Daejeon 305-811 (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Korea University of Science and Technology (UST), Daejeon 305-350 (Korea, Republic of)

    2015-06-01

    We have developed a high resolution alpha spectrometer with a magnetic calorimeter. The operating principle of the detector is the calorimetric measurement of the temperature increase from particle absorption in a gold foil absorber at milli-Kelvin temperatures. A magnetic calorimeter made of gold doped with erbium on a superconducting meander pickup coil was used to accurately measure the temperature change, thereby acting as an ultra-sensitive thermometer. The detector demonstrated 1.2 keV FWHM equivalent resolution in alpha particle detection with an {sup 241}Am source. Many peaks were observed in the low-energy region from the absorption of low-energy X-rays, gamma rays, and conversion electrons. An energy resolution of 400 eV FWHM was achieved for 60 keV gamma rays that were measured with the alpha particles. Possible applications of such high resolution detectors are discussed.

  2. Rapid hybrid encoding for high-resolution whole-brain fluid-attenuated imaging.

    Science.gov (United States)

    Lee, Hoonjae; Sohn, Chul-Ho; Park, Jaeseok

    2013-12-01

    Single-slab three-dimensional (3D) turbo spin-echo (TSE) imaging combined with inversion recovery (IR), which employs short, spatially non-selective refocusing pulses and signal prescription based variable refocusing flip angles (VFA) to increase imaging efficiency, was recently introduced to produce fluid-attenuated brain images for lesion detection. Despite the advantages, the imaging efficiency in this approach still remains limited because a substantially long time of inversion is needed to selectively suppress the signal intensity of cerebrospinal fluid (CSF) while fully recovering that of brain tissues. The purpose of this work is to develop a novel, rapid hybrid encoding method for highly efficient whole-brain fluid-attenuated imaging. In each time of repetition, volumetric data are continuously encoded using the hybrid modular acquisition in a sequential fashion even during IR signal transition, wherein reversed fast imaging with steady-state free precession (PSIF) is employed to encode intermediate-to-high spatial frequency signals prior to CSF nulling, while VFA-TSE is used to collect low-to-intermediate spatial frequency signals afterwards. Gradient-induced spin de-phasing between a pair of neighboring radio-frequency (RF) pulses in both PSIF and TSE modules is kept identical to avoid the occurrence of multiple echoes in a single acquisition window. Additionally, a two-step, alternate RF phase-cycling scheme is employed in the low spatial frequency region to eliminate free induction decay induced edge artifacts. Numerical simulations of the Bloch equations were performed to evaluate signal evolution of brain tissues along the echo train while optimizing imaging parameters. In vivo studies demonstrate that the proposed technique produces high-resolution isotropic fluid-attenuated whole-brain images in a clinically acceptable imaging time with substantially high signal-to-noise ratio for white matter while retaining lesion conspicuity.

  3. High Resolution Observations and Modeling of Small-Scale Solar Magnetic Elements

    Science.gov (United States)

    Berger, Thomas E.

    2001-01-01

    This research contract investigating the radiative transfer and dynamic physics of the smallest observable magnetic structures in the solar photosphere. Due to the lack of a high-resolution visible light satellite instrument for solar studies, all data were acquired using ground-based instrumentation. The primary goal of the investigation was to understand the formation and evolution of "G-band bright points" in relation to the associated magnetic elements. G-band bright points are small (on the order of 100 kin or less in diameter) bright signatures associated with magnetic flux elements in the photosphere. They are seen in the A2A-X2 4308 A molecular bandhead of the CH radical ill the solar spectrum and offer the highest spatial resolution and highest contrast "tracers" of small magnetic structure on the Sun.

  4. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance

    Science.gov (United States)

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm.

  5. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance.

    Science.gov (United States)

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm. PMID:25557860

  6. Compact magnet array for portable high-resolution NMR and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Danieli, Ernesto; Perlo, Juan; Bluemich, Bernhard; Casanova, Federico [ITMC, RWTH Aachen University (Germany)

    2010-07-01

    Portable NMR probes built from permanent magnets offer several advantages over conventional NMR systems. However, the inhomogeneity of the magnetic field generated by these sensors precludes their use in high resolution NMR spectroscopy and MRI. Recently we have demonstrated that the inhomogeneities of the magnetic field can be removed by providing the sensor with movable permanent magnets which allows generating and controlling harmonic field corrections by a mechanical shimming approach. In this work we present a high-performance magnet design based on this concept, which enables us to reduce the size of the magnet keeping the field strength and the sample volume constant. In particular, it was used to build a palm size magnet working in a volume large enough to fit conventional 5 mm NMR tubes where the high field homogeneity allowed us to measure proton NMR spectra of different solvents with a resolution better than 0.16 ppm at 30 MHz. By scaling the dimensions of the magnet the same geometry was optimized to build a portable MRI scanner for imaging samples of 4 cm DSV 1.

  7. Compact magnet array for portable high-resolution NMR and imaging

    International Nuclear Information System (INIS)

    Portable NMR probes built from permanent magnets offer several advantages over conventional NMR systems. However, the inhomogeneity of the magnetic field generated by these sensors precludes their use in high resolution NMR spectroscopy and MRI. Recently we have demonstrated that the inhomogeneities of the magnetic field can be removed by providing the sensor with movable permanent magnets which allows generating and controlling harmonic field corrections by a mechanical shimming approach. In this work we present a high-performance magnet design based on this concept, which enables us to reduce the size of the magnet keeping the field strength and the sample volume constant. In particular, it was used to build a palm size magnet working in a volume large enough to fit conventional 5 mm NMR tubes where the high field homogeneity allowed us to measure proton NMR spectra of different solvents with a resolution better than 0.16 ppm at 30 MHz. By scaling the dimensions of the magnet the same geometry was optimized to build a portable MRI scanner for imaging samples of 4 cm DSV 1.

  8. Los Alamos Meson Physics Facility high-resolution-spectrometer dipole magnets: a summary report

    International Nuclear Information System (INIS)

    This report explains the design, fabrication, measurement, optimization, and installation of two 122 metric ton electromagnets for the High Resolution Proton Spectrometer at the Los Alamos Meson Physics Facility. These two magnets are the principal components of the proton spectrometer, which has an energy resolution of less than or equal to 10-4 FWHM. Many technical problems occurred during fabrication, measurement, and optimization, and the majority have been successfully solved. We hope that this report will help others planning similar projects

  9. A True Multi-modality Approach for High Resolution Optical Imaging: Photo-Magnetic Imaging

    OpenAIRE

    Luk, Alex T.; Ha, Seunghoon; Nouizi, Farouk; Thayer, David; Lin, Yuting; Gulsen, Gultekin

    2014-01-01

    Multi-modality imaging leverages the competitive advantage of different imaging systems to improve the overall resolution and quantitative accuracy. Our new technique, Photo-Magnetic Imaging (PMI) is one of these true multi-modality imaging approaches, which can provide quantitative optical absorption map at MRI spatial resolution. PMI uses laser light to illuminate tissue and elevate its temperature while utilizing MR thermometry to measure the laser-induced temperature variation with high s...

  10. Providing and optimizing functional MR (Magnetic Resonance) of motor cortex of human brain by MRI ( Magnetic Resonance Imaging) facilities of Imam Khomeinie Hospital

    CERN Document Server

    Khosravie, H R

    2000-01-01

    During the stimulation, an observable increased signal (%2-%5)in respective sensory-motor cortex was obtained after correcting for partial volume effects, optimizing S/N,and incorporating small vowels. The 2 D F A S T functional image obtained by this method, showed an anatomical association of the increased signal with gray matter of sensory-motor cortex(in T 1 weighted image). The resultant data showed the feasibility of functional magnetic resonance imaging using optimized gradient echo sequences on a standard 1.5 T imager. Display of human brain cortical activity is accomplished using various techniques, by them different spatial and temporal resolution may be obtained. F MRI technique with proper spatial and temporal resolution due to its noninvasivity is one of the promising techniques for detection of brain activities. This can be used as an important tool by neurologists, since a great development has been achieved for display different brain function. This thesis report the results of simulation effe...

  11. Stellar magnetic field parameters from a Bayesian analysis of high-resolution spectropolarimetric observations

    OpenAIRE

    Petit, V.; Wade, G. A.

    2011-01-01

    In this paper we describe a Bayesian statistical method designed to infer the magnetic properties of stars observed using high-resolution circular spectropolarimetry in the context of large surveys. This approach is well suited for analysing stars for which the stellar rotation period is not known, and therefore the rotational phases of the observations are ambiguous. The model assumes that the magnetic observations correspond to a dipole oblique rotator, a situation commonly encountered in i...

  12. Improved Depiction of Pterygopalatine Fossa Anatomy Using Ultrahigh-Resolution Magnetic Resonance Imaging at 7 Tesla

    OpenAIRE

    Oomen, K. P. Q.; Pameijer, F. A.; Zwanenburg, J. J. M.; Hordijk, G J; De Ru, J. A.; Bleys, R L A W

    2012-01-01

    Purpose. To study the anatomy of the pterygopalatine fossa (PPF) using ultrahigh-resolution magnetic resonance imaging. Methods. A human cadaveric tissue block containing the pterygopalatine fossa was examined on a clinical 7-Tesla magnetic resonance imaging system. Subsequently, cryosections of the tissue block were created in a coronal plane. The cryosections were photographed and collected on adhesive tape. The on-tape sections were stained for Mallory-Cason, in order to detail the anatomi...

  13. Magneto-Optic Fiber Bragg Gratings with Application to High-Resolution Magnetic Field Sensors

    Institute of Scientific and Technical Information of China (English)

    Bao-Jian Wu; Ying Yang; Kun Qiu

    2008-01-01

    Magneto-optic fiber Bragg gratings (MFBG) based on magneto-optic materials have a lot of potential applications for sensing and optical signal processing. The transmission and reflection spectra of guided optical waves in the MFBG are investigated. According to the sensitivity of MFBG spectral lines to the magneto-optic coupling intensity varying with applied magnetic field, a novel magnetic field sensor of high-resolution up to 0.01 nm/(kA/m) is predicted.

  14. Partial-Homogeneity-Based Two-Dimensional High-Resolution Nuclear Magnetic Resonance Spectroscopy under Inhomogeneous Magnetic Fields.

    Science.gov (United States)

    Qiu, Wenqi; Wei, Zhiliang; Ding, Nan; Yang, Yu; Ye, Qimiao; Lin, Yulan; Chen, Zhong

    2016-05-18

    High-resolution multidimensional nuclear magnetic resonance (NMR) spectroscopy serves as an irreplaceable and versatile tool in various chemical investigations. In this study, a method based on the concept of partial homogeneity is developed to offer two-dimensional (2D) high-resolution NMR spectra under inhomogeneous fields. Oscillating gradients are exerted to encode the high-resolution information, and a field-inhomogeneity correction algorithm based on pattern recognition is designed to recover high-resolution spectra. Under fields where inhomogeneity primarily distributes along a single orientation, the proposed method will improve performances of 2D NMR spectroscopy without increasing the experimental duration or significant loss in sensitivity, and thus may open important perspectives for studies of inhomogeneous chemical systems.

  15. Establishing resolution-improved NMR spectroscopy in high magnetic fields with unknown spatiotemporal variations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiyong; Cai, Shuhui; Zheng, Zhenyao; Lin, Yulan, E-mail: chenz@xmu.edu.cn, E-mail: lylfj2005@xmu.edu.cn; Chen, Zhong, E-mail: chenz@xmu.edu.cn, E-mail: lylfj2005@xmu.edu.cn [Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen (China); Smith, Pieter E. S. [Chemical Physics Department, Weizmann Institute of Science, Rehovot (Israel)

    2015-12-28

    A half-century quest for higher magnetic fields has been an integral part of the progress undergone in the Nuclear Magnetic Resonance (NMR) study of materials’ structure and dynamics. Because 2D NMR relies on systematic changes in coherences’ phases as a function of an encoding time varied over a series of independent experiments, it generally cannot be applied in temporally unstable fields. This precludes most NMR methods from being used to characterize samples situated in hybrid or resistive magnets that are capable of achieving extremely high magnetic field strength. Recently, “ultrafast” NMR has been developed into an effective and widely applicable methodology enabling the acquisition of a multidimensional NMR spectrum in a single scan; it can therefore be used to partially mitigate the effects of temporally varying magnetic fields. Nevertheless, the strong interference of fluctuating fields with the spatial encoding of ultrafast NMR still severely restricts measurement sensitivity and resolution. Here, we introduce a strategy for obtaining high resolution NMR spectra that exploits the immunity of intermolecular zero-quantum coherences (iZQCs) to field instabilities and inhomogeneities. The spatial encoding of iZQCs is combined with a J-modulated detection scheme that removes the influence of arbitrary field inhomogeneities during acquisition. This new method can acquire high-resolution one-dimensional NMR spectra in large inhomogeneous and fluctuating fields, and it is tested with fields experimentally modeled to mimic those of resistive and resistive-superconducting hybrid magnets.

  16. Establishing resolution-improved NMR spectroscopy in high magnetic fields with unknown spatiotemporal variations

    Science.gov (United States)

    Zhang, Zhiyong; Smith, Pieter E. S.; Cai, Shuhui; Zheng, Zhenyao; Lin, Yulan; Chen, Zhong

    2015-12-01

    A half-century quest for higher magnetic fields has been an integral part of the progress undergone in the Nuclear Magnetic Resonance (NMR) study of materials' structure and dynamics. Because 2D NMR relies on systematic changes in coherences' phases as a function of an encoding time varied over a series of independent experiments, it generally cannot be applied in temporally unstable fields. This precludes most NMR methods from being used to characterize samples situated in hybrid or resistive magnets that are capable of achieving extremely high magnetic field strength. Recently, "ultrafast" NMR has been developed into an effective and widely applicable methodology enabling the acquisition of a multidimensional NMR spectrum in a single scan; it can therefore be used to partially mitigate the effects of temporally varying magnetic fields. Nevertheless, the strong interference of fluctuating fields with the spatial encoding of ultrafast NMR still severely restricts measurement sensitivity and resolution. Here, we introduce a strategy for obtaining high resolution NMR spectra that exploits the immunity of intermolecular zero-quantum coherences (iZQCs) to field instabilities and inhomogeneities. The spatial encoding of iZQCs is combined with a J-modulated detection scheme that removes the influence of arbitrary field inhomogeneities during acquisition. This new method can acquire high-resolution one-dimensional NMR spectra in large inhomogeneous and fluctuating fields, and it is tested with fields experimentally modeled to mimic those of resistive and resistive-superconducting hybrid magnets.

  17. High-resolution nuclear magnetic resonance measurements in inhomogeneous magnetic fields: A fast two-dimensional J-resolved experiment.

    Science.gov (United States)

    Huang, Yuqing; Lin, Yung-Ya; Cai, Shuhui; Yang, Yu; Sun, Huijun; Lin, Yanqin; Chen, Zhong

    2016-03-14

    High spectral resolution in nuclear magnetic resonance (NMR) is a prerequisite for achieving accurate information relevant to molecular structures and composition assignments. The continuous development of superconducting magnets guarantees strong and homogeneous static magnetic fields for satisfactory spectral resolution. However, there exist circumstances, such as measurements on biological tissues and heterogeneous chemical samples, where the field homogeneity is degraded and spectral line broadening seems inevitable. Here we propose an NMR method, named intermolecular zero-quantum coherence J-resolved spectroscopy (iZQC-JRES), to face the challenge of field inhomogeneity and obtain desired high-resolution two-dimensional J-resolved spectra with fast acquisition. Theoretical analyses for this method are given according to the intermolecular multiple-quantum coherence treatment. Experiments on (a) a simple chemical solution and (b) an aqueous solution of mixed metabolites under externally deshimmed fields, and on (c) a table grape sample with intrinsic field inhomogeneity from magnetic susceptibility variations demonstrate the feasibility and applicability of the iZQC-JRES method. The application of this method to inhomogeneous chemical and biological samples, maybe in vivo samples, appears promising.

  18. In vivo 3D digital atlas database of the adult C57BL/6J mouse brain by magnetic resonance microscopy

    Directory of Open Access Journals (Sweden)

    Yu Ma

    2008-04-01

    Full Text Available In this study, a 3D digital atlas of the live mouse brain based on magnetic resonance microscopy (MRM is presented. C57BL/6J adult mouse brains were imaged in vivo on a 9.4 Tesla MR instrument at an isotropic spatial resolution of 100 μm. With sufficient signal-to-noise (SNR and contrast-to-noise ratio (CNR, 20 brain regions were identified. Several atlases were constructed including 12 individual brain atlases, an average atlas, a probabilistic atlas and average geometrical deformation maps. We also investigated the feasibility of using lower spatial resolution images to improve time efficiency for future morphological phenotyping. All of the new in vivo data were compared to previous published in vitro C57BL/6J mouse brain atlases and the morphological differences were characterized. Our analyses revealed significant volumetric as well as unexpected geometrical differences between the in vivo and in vitro brain groups which in some instances were predictable (e.g. collapsed and smaller ventricles in vitro but not in other instances. Based on these findings we conclude that although in vitro datasets, compared to in vivo images, offer higher spatial resolutions, superior SNR and CNR, leading to improved image segmentation, in vivo atlases are likely to be an overall better geometric match for in vivo studies, which are necessary for longitudinal examinations of the same animals and for functional brain activation studies. Thus the new in vivo mouse brain atlas dataset presented here is a valuable complement to the current mouse brain atlas collection and will be accessible to the neuroscience community on our public domain mouse brain atlas website.

  19. Magnetic resonance images of the brain of a dwarf sperm whale (Kogia simus).

    Science.gov (United States)

    Marino, L; Sudheimer, K; Pabst, D A; McLellan, W A; Johnson, J I

    2003-07-01

    Cetacean (dolphin, whale and porpoise) brains are among the least studied mammalian brains because of the difficulty of collecting and histologically preparing such relatively rare and large specimens. Among cetaceans, there exist relatively few studies of the brain of the dwarf sperm whale (Kogia simus). Magnetic resonance imaging (MRI) offers a means of observing the internal structure of the brain when traditional histological procedures are not practical. Therefore, MRI has become a critical tool in the study of the brain of cetaceans and other large species. This paper represents the first MRI-based anatomically labelled three-dimensional description of the dwarf sperm whale brain. Coronal plane sections of the brain of a sub-adult dwarf sperm whale were originally acquired and used to produce virtual digital scans in the other two orthogonal spatial planes. A sequential set of images in all three planes has been anatomically labelled and displays the proportions and positions of major neuroanatomical features. PMID:12892406

  20. Advanced techniques in magnetic resonance imaging of the brain in children with ADHD

    Energy Technology Data Exchange (ETDEWEB)

    Pastura, Giuseppe, E-mail: giuseppe.pastura@terra.com.b [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Pediatria; Mattos, Paulo [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Psiquiatria; Gasparetto, Emerson Leandro [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Radiologia; Araujo, Alexandra Prufer de Queiroz Campos [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Neuropediatria

    2011-04-15

    Attention deficit hyperactivity disorder (ADHD) affects about 5% of school-aged child. Previous published works using different techniques of magnetic resonance imaging (MRI) have demonstrated that there may be some differences between the brain of people with and without this condition. This review aims at providing neurologists, pediatricians and psychiatrists an update on the differences between the brain of children with and without ADHD using advanced techniques of magnetic resonance imaging such as diffusion tensor imaging, brain volumetry and cortical thickness, spectroscopy and functional MRI. Data was obtained by a comprehensive, non-systematic review of medical literature. The regions with a greater number of abnormalities are splenium of the corpus callosum, cingulated gyrus, caudate nucleus, cerebellum, striatum, frontal and temporal cortices. The brain regions where abnormalities are observed in studies of diffusion tensor, volumetry, spectroscopy and cortical thickness are the same involved in neurobiological theories of ADHD coming from studies with functional magnetic resonance imaging. (author)

  1. EMAG2. A 2-arc-minute resolution Earth magnetic anomaly grid compiled from satellite, airborne and marine magnetic measurements

    International Nuclear Information System (INIS)

    Complete text of publication follows. Airborne and marine magnetic data have been collected for more than half a century, providing extensive coverage of the Earth. Due to the changing main field from the Earth's core, and due to differences in quality and coverage, combining these data to a consistent global magnetic anomaly grid is challenging. A key ingredient is the long wavelength magnetic field observed by the low-orbiting CHAMP satellite. To produce a homogeneous grid, the marine and aeromagnetic trackline data are first line-leveled and then merged with the existing grids of continental-scale compilations by Least Squares Collocation. The method takes the anisotropy of the oceanic magnetic field into account. This leads to an improved representation of oceanic magnetic lineations and allows for the interpolation between adjacent tracks in sparsely surveyed regions, particularly in the southern oceans. In the final processing step the short-to- intermediate wavelengths of the near-surface grid are merged with the latest CHAMP satellite magnetic anomaly model MF6 (http://geomag.org/models/MF6.html). In analogy to NGDC's 2-arc-minute resolution ETOPO2 grid, the new magnetic anomaly grid is named EMAG2. The grid is available in digital form and as plug-ins for NASA World Wind, Google Earth and Google Maps at http://geomag.org.

  2. Enhancement of the amplitude of somatosensory evoked potentials following magnetic pulse stimulation of the human brain.

    Science.gov (United States)

    Seyal, M; Browne, J K; Masuoka, L K; Gabor, A J

    1993-01-01

    In this study we have demonstrated an enhancement of cortically generated wave forms of the somatosensory evoked potential (SEP) following magnetic pulse stimulation of the human brain. Subcortically generated activity was unaltered. The enhancement of SEP amplitude was greatest when the median nerve was stimulated 30-70 msec following magnetic pulse stimulation over the contralateral parietal scalp. We posit that the enhancement of the SEP is the result of synchronization of pyramidal cells in the sensorimotor cortex resulting from the magnetic pulse.

  3. Reversible lesions in the brain parenchyma in Wilson’s disease conifrmed by magnetic resonance imaging:earlier administration of chelating therapy can reduce the damage to the brain

    Institute of Scientific and Technical Information of China (English)

    Duko B Kozi; Igor Petrovi; Marina Svetel; Tatjana Pekmezovi; Aleksandar Ragaji; Vladimir S Kosti

    2014-01-01

    The aim of this study was to evaluate the resolution of brain lesions in patients with Wilson’s disease during the long-term chelating therapy using magnetic resonance imaging and a possible signiifcance of the time latency between the initial symptoms of the disease and the introduction of this therapy. Initial magnetic resonance examination was performed in 37 patients with proven neurological form of Wilson’s disease with cerebellar, parkinsonian and dystonic presentation. Magnetic resonance reexamination was done 5.7 ± 1.3 years later in 14 patients. Patients were divided into: group A, where chelating therapy was initiated < 24 months from the ifrst symp-toms and group B, where the therapy started≥ 24 months after the initial symptoms. Symmetry of the lesions was seen in 100% of patients. There was a signiifcant difference between groups A and B regarding complete resolution of brain stem and putaminal lesions (P= 0.005 andP=0.024, respectively). If the correct diagnosis and adequate treatment are not established less than 24 months after onset of the symptoms, irreversible lesions in the brain parenchyma could be ex-pected. Signal abnormalities on magnetic resonance imaging might therefore, at least in the early stages, represent reversible myelinolisis or cytotoxic edema associated with copper toxicity.

  4. A magnetic-free high-resolution parabolic mirror time-of-flight electron energy spectrometer

    Institute of Scientific and Technical Information of China (English)

    张戈; 沈鸿元; 曾瑞荣; 黄呈辉; 林文雄; 黄见洪

    2001-01-01

    The principle and structure of a magnetic-free high-resolution high-efficiency parabolic mirror time-offligght electron energy spectrometer are presented. The electron energy spectrum of Nz in a flight tube is measured using a 105 fs Ti:sappbire laser under different gas pressures.

  5. Study of coals by high resolution solid state nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    杨保联; 冯继文; 周建威; 李丽云; 叶朝辉

    1999-01-01

    By using high resolution solid state nuclear magnetic resonance method, six coal samples coming from four countries were investigated. Twelve structural parameters of these samples were measured and compared with those of Chinese coals. Spectral editing experiment was carried out and 15N NMR spectrum was obtained.

  6. Brain-heart interactions: challenges and opportunities with functional magnetic resonance imaging at ultra-high field.

    Science.gov (United States)

    Chang, Catie; Raven, Erika P; Duyn, Jeff H

    2016-05-13

    Magnetic resonance imaging (MRI) at ultra-high field (UHF) strengths (7 T and above) offers unique opportunities for studying the human brain with increased spatial resolution, contrast and sensitivity. However, its reliability can be compromised by factors such as head motion, image distortion and non-neural fluctuations of the functional MRI signal. The objective of this review is to provide a critical discussion of the advantages and trade-offs associated with UHF imaging, focusing on the application to studying brain-heart interactions. We describe how UHF MRI may provide contrast and resolution benefits for measuring neural activity of regions involved in the control and mediation of autonomic processes, and in delineating such regions based on anatomical MRI contrast. Limitations arising from confounding signals are discussed, including challenges with distinguishing non-neural physiological effects from the neural signals of interest that reflect cardiorespiratory function. We also consider how recently developed data analysis techniques may be applied to high-field imaging data to uncover novel information about brain-heart interactions.

  7. Brain-heart interactions: challenges and opportunities with functional magnetic resonance imaging at ultra-high field.

    Science.gov (United States)

    Chang, Catie; Raven, Erika P; Duyn, Jeff H

    2016-05-13

    Magnetic resonance imaging (MRI) at ultra-high field (UHF) strengths (7 T and above) offers unique opportunities for studying the human brain with increased spatial resolution, contrast and sensitivity. However, its reliability can be compromised by factors such as head motion, image distortion and non-neural fluctuations of the functional MRI signal. The objective of this review is to provide a critical discussion of the advantages and trade-offs associated with UHF imaging, focusing on the application to studying brain-heart interactions. We describe how UHF MRI may provide contrast and resolution benefits for measuring neural activity of regions involved in the control and mediation of autonomic processes, and in delineating such regions based on anatomical MRI contrast. Limitations arising from confounding signals are discussed, including challenges with distinguishing non-neural physiological effects from the neural signals of interest that reflect cardiorespiratory function. We also consider how recently developed data analysis techniques may be applied to high-field imaging data to uncover novel information about brain-heart interactions. PMID:27044994

  8. Quantitative assessment of brain perfusion with magnetic resonance imaging

    NARCIS (Netherlands)

    Bleeker, Egbert Jan Willem

    2011-01-01

    This thesis focuses on assessing blood supply to brain tissue using MRI. For Dynamic Susceptibility Contrast-MRI a series of images is acquired during the passage of a bolus contrast agent through the brain up to the point that the contrast agent is equally mixed within the total blood pool. The tis

  9. Scrutinizing brain magnetic resonance imaging patterns in Angelman syndrome

    Directory of Open Access Journals (Sweden)

    Marcio Leyser

    2016-01-01

    Conclusion: The lack of specific changes in the brain MRI of children with AS observed in this case series rendered brain MRI a less helpful complementary test. Thus, a definitive diagnosis of AS could only be established on molecular biology that was undertaken based on the clinical suspicion of AS.

  10. A hybrid CPU-GPU accelerated framework for fast mapping of high-resolution human brain connectome.

    Directory of Open Access Journals (Sweden)

    Yu Wang

    Full Text Available Recently, a combination of non-invasive neuroimaging techniques and graph theoretical approaches has provided a unique opportunity for understanding the patterns of the structural and functional connectivity of the human brain (referred to as the human brain connectome. Currently, there is a very large amount of brain imaging data that have been collected, and there are very high requirements for the computational capabilities that are used in high-resolution connectome research. In this paper, we propose a hybrid CPU-GPU framework to accelerate the computation of the human brain connectome. We applied this framework to a publicly available resting-state functional MRI dataset from 197 participants. For each subject, we first computed Pearson's Correlation coefficient between any pairs of the time series of gray-matter voxels, and then we constructed unweighted undirected brain networks with 58 k nodes and a sparsity range from 0.02% to 0.17%. Next, graphic properties of the functional brain networks were quantified, analyzed and compared with those of 15 corresponding random networks. With our proposed accelerating framework, the above process for each network cost 80∼150 minutes, depending on the network sparsity. Further analyses revealed that high-resolution functional brain networks have efficient small-world properties, significant modular structure, a power law degree distribution and highly connected nodes in the medial frontal and parietal cortical regions. These results are largely compatible with previous human brain network studies. Taken together, our proposed framework can substantially enhance the applicability and efficacy of high-resolution (voxel-based brain network analysis, and have the potential to accelerate the mapping of the human brain connectome in normal and disease states.

  11. High-Resolution Observations of Flare Precursors and Their Relationship with Magnetic Channels

    Science.gov (United States)

    Wang, Haimin; Xu, Yan; Ahn, Kwangsu; Jing, Ju; Liu, Chang; Deng, Na; Huang, Nengyi; Gary, Dale E.; Cao, Wenda

    2016-05-01

    The study of precursors of flares is important for understanding the basic magnetic instability leading to solar flares, which can aid the forecasting of eruptions potentially related to severe space weather effects. Although literatures reported many important clues, high-resolution observations of pre-flare activities before a well-observed solar flare have been rare. Even rarely, the associated magnetic structures in fine scale (below 1") were also observed. In this study we take advantage of multiwavelength high-resolution observations completely covering the 2015 June 22 M6.6 flare, which were obtained under excellent seeing condition with the 1.6 m New Solar Telescope (NST) at Big Bear Solar Observatory. The NST data includes observations of the H-alpha line in five spectral positions at a spatial resolution of 0.1" and magnetograms at a resolution of 0.25". These are complemented by IRIS UV observations with a resolution of 0.25". We find that there are two episodes of pre-flare brightenings (precursors), which are spatially associated with magnetic channels, i.e., elongated structures comprising alternating magnetic polarity inversion lines (Zirin & Wang, 1993, Nature, 363, 426). The pre-flare chromospheric and coronal features reflect an extremely sheared magnetic topology, while the initiation of main flare brightenings correspond to a much less sheared configuration. RHESSI HXR observations reveal that the precursors have both thermal and nonthermal components, and the latter is further evidenced by the microwave observations of the newly expanded Solar Radio Array at Owens Valley.We further investigate the electric current system above the magnetic channels using NLFFF extrapolations, which show strong current sheets above the channel structure. This is consistent with the MHD modeling of Kusano et al (2012, Ap.J., 760, 31), who noted the importance of localized small-scale magnetic structure in triggering the eruption of the whole active region. We

  12. High resolution spectroscopy and chemical shift imaging of hyperpolarized 129Xe dissolved in the human brain in vivo at 1.5 tesla

    Science.gov (United States)

    Rao, Madhwesha; Stewart, Neil J.; Norquay, Graham; Griffiths, Paul D.

    2016-01-01

    Purpose Upon inhalation, xenon diffuses into the bloodstream and is transported to the brain, where it dissolves in various compartments of the brain. Although up to five chemically distinct peaks have been previously observed in 129Xe rat head spectra, to date only three peaks have been reported in the human head. This study demonstrates high resolution spectroscopy and chemical shift imaging (CSI) of 129Xe dissolved in the human head at 1.5 Tesla. Methods A 129Xe radiofrequency coil was built in‐house and 129Xe gas was polarized using spin‐exchange optical pumping. Following the inhalation of 129Xe gas, NMR spectroscopy was performed with spectral resolution of 0.033 ppm. Two‐dimensional CSI in all three anatomical planes was performed with spectral resolution of 2.1 ppm and voxel size 20 mm × 20 mm. Results Spectra of hyperpolarized 129Xe dissolved in the human head showed five distinct peaks at 188 ppm, 192 ppm, 196 ppm, 200 ppm, and 217 ppm. Assignment of these peaks was consistent with earlier studies. Conclusion High resolution spectroscopy and CSI of hyperpolarized 129Xe dissolved in the human head has been demonstrated. For the first time, five distinct NMR peaks have been observed in 129Xe spectra from the human head in vivo. Magn Reson Med 75:2227–2234, 2016. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:27080441

  13. First high-resolution near-seafloor survey of magnetic anomalies of the South China Sea

    Science.gov (United States)

    Lin, J.; Xu, X.; Li, C.; Sun, Z.; Zhu, J.; Zhou, Z.; Qiu, N.

    2013-12-01

    We successfully conducted the first high-resolution near-seafloor magnetic survey of the Central, Southwest, and Northern Central Basins of the South China Sea (SCS) during two cruises on board Chinese R/V HaiYangLiuHao in October-November 2012 and March-April 2013, respectively. Measurements of magnetic field were made along four long survey lines, including (1) a NW-SE across-isochron profile transecting the Southwest Basin and covering all ages of the oceanic crust (Line CD); (2) a N-S across-isochron profile transecting the Central Basin (Line AB); and (3) two sub-parallel NE-SW across-isochron profiles transecting the Northern Central Basin of the SCS (Lines D and E). A three-axis magnetometer was mounted on a deep-tow vehicle, flying within 0.6 km above the seafloor. The position of the tow vehicle was provided by an ultra-short baseline navigation system along Lines D and E, while was estimated using shipboard GPS along Lines AB and CD. To investigate crustal magnetization, we first removed the International Geomagnetic Reference Field (IGRF) of 2010 from the measured magnetic data, and then downward continued the resultant magnetic field data to a horizontal plane at a water depth of 4.5 km to correct for variation due to the fishing depth of the deep-tow vehicle. Finally, we calculated magnetic anomalies at various water depths after reduction-to-the-pole corrections. We also constructed polarity reversal block (PRB) models of crustal magnetization by matching peaks and troughs of the observed magnetic field anomaly. Our analysis yielded the following results: (1) The near-bottom magnetic anomaly showed peak-to-trough amplitudes of more than 2,500 nT, which are several times of the anomaly amplitudes at the sea surface, illustrating that deep-tow measurements acquired much higher spatial resolutions. (2) The deep-tow data revealed several distinctive magnetic anomalies with wavelengths of 5-15 km and amplitudes of several hundred nT. These short

  14. Low temperature magnetic analysis in the identification of iron compounds from human brain tumour tissue

    Energy Technology Data Exchange (ETDEWEB)

    Brem, F [Institute of Geophysics, ETH-Hoenggerberg, CH-8093 Zurich (Switzerland); Hirt, A M [Institute of Geophysics, ETH-Hoenggerberg, CH-8093 Zurich (Switzerland); Simon, C [Neurology/EEG, University Hospital Zurich, CH-8091 Zurich (Switzerland); Wieser, H-G [Neurology/EEG, University Hospital Zurich, CH-8091 Zurich (Switzerland); Dobson, J [Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, ST4 7QB, (United Kingdom)

    2005-01-01

    In the brain, iron plays an important role, but also is potentially toxic if iron metabolism is disrupted. Excess iron accumulation in the brain has been shown to be associated with neurodegenerative diseases. However, identification of iron compounds in human tissue is difficult because concentrations are very low. Three types of magnetic methods were used to characterize iron compounds in tumour tissue from epileptic patients. Isothermal Remanent Magnetization (IRM) was measured at 77 K and 300 K and reveals a low-coercivity phase with the properties of magnetite or maghemite. Induced magnetization was measured between 2 K and 300 K after cooling in zero-field and in a 50 mT field. These curves reveal an average blocking temperature of 11 K, which is compatible with ferritin. The results of this study show that the combination of different magnetic methods provides a useful and sensitive tool for the characterisation of magnetic iron compounds in human tissue.

  15. High-resolution imaging of the large non-human primate brain using microPET: a feasibility study

    International Nuclear Information System (INIS)

    The neuroanatomy and physiology of the baboon brain closely resembles that of the human brain and is well suited for evaluating promising new radioligands in non-human primates by PET and SPECT prior to their use in humans. These studies are commonly performed on clinical scanners with 5 mm spatial resolution at best, resulting in sub-optimal images for quantitative analysis. This study assessed the feasibility of using a microPET animal scanner to image the brains of large non-human primates, i.e. papio hamadryas (baboon) at high resolution. Factors affecting image accuracy, including scatter, attenuation and spatial resolution, were measured under conditions approximating a baboon brain and using different reconstruction strategies. Scatter fraction measured 32% at the centre of a 10 cm diameter phantom. Scatter correction increased image contrast by up to 21% but reduced the signal-to-noise ratio. Volume resolution was superior and more uniform using maximum a posteriori (MAP) reconstructed images (3.2-3.6 mm3 FWHM from centre to 4 cm offset) compared to both 3D ordered subsets expectation maximization (OSEM) (5.6-8.3 mm3) and 3D reprojection (3DRP) (5.9-9.1 mm3). A pilot 18F-2-fluoro-2-deoxy-d-glucose ([18F]FDG) scan was performed on a healthy female adult baboon. The pilot study demonstrated the ability to adequately resolve cortical and sub-cortical grey matter structures in the baboon brain and improved contrast when images were corrected for attenuation and scatter and reconstructed by MAP. We conclude that high resolution imaging of the baboon brain with microPET is feasible with appropriate choices of reconstruction strategy and corrections for degrading physical effects. Further work to develop suitable correction algorithms for high-resolution large primate imaging is warranted

  16. High-resolution ultrasound evaluation of experimental brain abscess evolution: comparison with computed tomography and neuropathology

    Energy Technology Data Exchange (ETDEWEB)

    Enzmann, D.R.; Britt, R.H.; Lyons, B.; Carroll, B.; Wilson, D.A.; Buxton, J.

    1982-01-01

    Computed tomographic (CT) and high-resolution ultrasound (HRUS) imaging of experimental brain abscess were correlated with neuropathologic findings in nine mongrel dogs. The HRUS scan was more sensitive to different histologic features than the CT scan but both accurately delineated the evolution of the experimental brain abscess. All stages of abscess evolution were characterized by an appearance of an echogenic rim with a hypoechoic center. In the early stages the echogenicity of the abscess was related primarily to marked cellular infiltration while in the late stages extensive collagen deposition correlated closely with the echo pattern. The size of the abscess in the cerebritis stages appeared smaller on the HRUS scan than on the CT scan because the latter modality detected the extensive cerebritis around the developing necrotic center whereas the HRUS scan did not. This discrepancy disappeared in the capsule stages. The HRUS scan provided a more accurate depiction of the neuropathologic characteristics of the necrotic center than did the CT scan. Healing of the abscess, indicated by a decrease in size of the hypoechoic center, was accurately detected by the HRUS scan.

  17. High-resolution ultrasound evaluation of experimental brain abscess evolution: comparison with computed tomography and neuropathology

    International Nuclear Information System (INIS)

    Computed tomographic (CT) and high-resolution ultrasound (HRUS) imaging of experimental brain abscess were correlated with neuropathologic findings in nine mongrel dogs. The HRUS scan was more sensitive to different histologic features than the CT scan but both accurately delineated the evolution of the experimental brain abscess. All stages of abscess evolution were characterized by an appearance of an echogenic rim with a hypoechoic center. In the early stages the echogenicity of the abscess was related primarily to marked cellular infiltration while in the late stages extensive collagen deposition correlated closely with the echo pattern. The size of the abscess in the cerebritis stages appeared smaller on the HRUS scan than on the CT scan because the latter modality detected the extensive cerebritis around the developing necrotic center whereas the HRUS scan did not. This discrepancy disappeared in the capsule stages. The HRUS scan provided a more accurate depiction of the neuropathologic characteristics of the necrotic center than did the CT scan. Healing of the abscess, indicated by a decrease in size of the hypoechoic center, was accurately detected by the HRUS scan

  18. High resolution mapping of modafinil induced changes in glutamate level in rat brain.

    Directory of Open Access Journals (Sweden)

    Mohammad Haris

    Full Text Available Modafinil is marketed in the United States for the treatment of narcolepsy and daytime somnolence due to shift-work or sleep apnea. Investigations of this drug in the treatment of cocaine and nicotine dependence in addition to disorders of executive function are also underway. Modafinil has been known to increase glutamate levels in rat brain models. Proton magnetic resonance spectroscopy (1HMRS has been commonly used to detect the glutamate (Glu changes in vivo. In this study, we used a recently described glutamate chemical exchange saturation transfer (GluCEST imaging technique to measure Modafinil induced regional Glu changes in rat brain and compared the results with Glu concentration measured by single voxel 1HMRS. No increases in either GluCEST maps or 1HMRS were observed after Modafinil injection over a period of 5 hours. However, a significant increase in GluCEST (19 ± 4.4% was observed 24 hours post Modafinil administration, which is consistent with results from previous biochemical studies. This change was not consistently seen with 1HMRS. GluCEST mapping allows regional cerebral Glu changes to be measured and may provide a useful clinical biomarker of Modafinil effects for the management of patients with sleep disorders and addiction.

  19. Ultrahigh-spatial-resolution chemical and magnetic imaging by laser-based photoemission electron microscopy

    International Nuclear Information System (INIS)

    We report the first experiments carried out on a new chemical and magnetic imaging system, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with a continuous-wave deep-ultraviolet laser. Threshold photoemission is sensitive to the chemical and magnetic structures of the surface of materials. The spatial resolution of PEEM is limited by space charging when using pulsed photon sources as well as aberrations in the electron optics. We show that the use of a continuous-wave laser enabled us to overcome such a limit by suppressing the space-charge effect, allowing us to obtain a resolution of approximately 2.6 nm. With this system, we demonstrated the imaging of surface reconstruction domains on Si(001) by linear dichroism with normal incidence of the laser beam. We also succeeded in magnetic imaging of thin films with the use of magnetic circular dichroism near the Fermi level. The unique features of the ultraviolet laser will give us fast switching of the incident angles and polarizations of the photon source, which will be useful for the characterization of antiferromagnetic materials as well as ferromagnetic materials

  20. Estimating brain age using high-resolution pattern recognition: Younger brains in long-term meditation practitioners.

    Science.gov (United States)

    Luders, Eileen; Cherbuin, Nicolas; Gaser, Christian

    2016-07-01

    Normal aging is known to be accompanied by loss of brain substance. The present study was designed to examine whether the practice of meditation is associated with a reduced brain age. Specific focus was directed at age fifty and beyond, as mid-life is a time when aging processes are known to become more prominent. We applied a recently developed machine learning algorithm trained to identify anatomical correlates of age in the brain translating those into one single score: the BrainAGE index (in years). Using this validated approach based on high-dimensional pattern recognition, we re-analyzed a large sample of 50 long-term meditators and 50 control subjects estimating and comparing their brain ages. We observed that, at age fifty, brains of meditators were estimated to be 7.5years younger than those of controls. In addition, we examined if the brain age estimates change with increasing age. While brain age estimates varied only little in controls, significant changes were detected in meditators: for every additional year over fifty, meditators' brains were estimated to be an additional 1month and 22days younger than their chronological age. Altogether, these findings seem to suggest that meditation is beneficial for brain preservation, effectively protecting against age-related atrophy with a consistently slower rate of brain aging throughout life. PMID:27079530

  1. A Novel Method for Brain MRI Super-resolution by Wavelet-based POCS and Adaptive Edge Zoom

    Directory of Open Access Journals (Sweden)

    N. Hema Rajini,

    2010-10-01

    Full Text Available This paper aims to make the super-resolution of a high-resolution image from a sequence of low-resolution frames containing non-stationary objects. The challenges of making super-resolution image, like unavoidable smoothing effects, introduction of artifacts, computational efficiency in time and computational efficiency in memory requirements, are considered and a novel method is proposed to solve these problems. The proposed method handles the super-resolution process by using wavelet based projection-onto-convex-set with adaptive edge zoom algorithm. Adaptive edge zoom algorithm address the problem of producing enlarged picture from the given digital image. Wavelet based projection-onto-convex-set method is usedto enhance spatial resolution of MRI brain images from a temporal sequence. This method produces more clarity with high peak signal-to-noise ratio.

  2. A challenge for probing the statistics of interstellar magnetic fields: beyond the Planck resolution with Herschel

    Science.gov (United States)

    Bracco, Andrea; André, Philippe; Boulanger, Francois

    2015-08-01

    The recent Planck results in polarization at sub-mm wavelengths allow us to gain insight into the Galactic magnetic field topology, revealing its statistical correlation with matter, from the diffuse interstellar medium (ISM), to molecular clouds (MCs) (Planck intermediate results. XXXII, XXXIII, XXXV). This correlation has a lot to tell us about the dynamics of the turbulent ISM, stressing the importance of considering magnetic fields in the formation of structures, some of which eventually undergo gravitational collapse producing new star-forming cores.Investigating the early phases of star formation has been a fundamental scope of the Herschel Gould Belt survey collaboration (http://gouldbelt-herschel.cea.fr), which, in the last years, has thoroughly characterized, at a resolution of few tens of arcseconds, the statistics of MCs, such as their filamentary structure, kinematics and column density.Although at lower angular resolution, the Planck maps of dust emission at 353GHz, in intensity and polarization, show that all MCs are complex environments, where we observe a non-trivial correlation between the magnetic field and their density structure. This result opens new perspectives on their formation and evolution, which we have started to explore.In this talk, I will present first results of a comparative analysis of the Herschel-Planck data, where we combine the high resolution Herschel maps of some MCs of the Gould Belt with the Planck polarization data, which sample the structure of the field weighted by the density.In particular, I will discuss the large-scale envelopes of the selected MCs, and, given the correlation between magnetic field and matter, I will show how to make use of the high resolution information of the density structure provided by Herschel to investigate the statistics of interstellar magnetic fields in the Planck data.

  3. Investigation of high-resolution functional magnetic resonance imaging by means of surface and array radiofrequency coils at 7 T.

    Science.gov (United States)

    van der Zwaag, Wietske; Marques, José P; Hergt, Martin; Gruetter, Rolf

    2009-10-01

    In this investigation, high-resolution, 1x1x1-mm(3) functional magnetic resonance imaging (fMRI) at 7 T is performed using a multichannel array head coil and a surface coil approach. Scan geometry was optimized for each coil separately to exploit the strengths of both coils. Acquisitions with the surface coil focused on partial brain coverage, while whole-brain coverage fMRI experiments were performed with the array head coil. BOLD sensitivity in the occipital lobe was found to be higher with the surface coil than with the head array, suggesting that restriction of signal detection to the area of interest may be beneficial for localized activation studies. Performing independent component analysis (ICA) decomposition of the fMRI data, we consistently detected BOLD signal changes and resting state networks. In the surface coil data, a small negative BOLD response could be detected in these resting state network areas. Also in the data acquired with the surface coil, two distinct components of the positive BOLD signal were consistently observed. These two components were tentatively assigned to tissue and venous signal changes. PMID:19261421

  4. Magnetic-resonance-imaging-coupled broadband near-infrared tomography system for small animal brain studies

    Science.gov (United States)

    Xu, Heng; Springett, Roger; Dehghani, Hamid; Pogue, Brian W.; Paulsen, Keith D.; Dunn, Jeff F.

    2005-04-01

    A novel magnetic-resonance-coupled broadband near-infrared (NIR) tomography system for small animal brain studies is described. Several features of the image formation approach are new in NIR tomography and represent major advances in the path to recovering high-resolution hemoglobin and oxygen saturation images of tissue. The NIR data were broadband and continuous wave and were used along with a second-derivative-based estimation of the path length from water absorption. The path length estimation from water was then used along with the attenuation spectrum to recover absorption and reduced scattering coefficient images at multiple wavelengths and then to recover images of total hemoglobin and oxygen saturation. Going beyond these basics of NIR tomography, software has been developed to allow inclusion of structures derived from MR imaging (MRI) for the external and internal tissue boundaries, thereby improving the accuracy and spatial resolution of the properties in each tissue type. The system has been validated in both tissue-simulating phantoms, with 10% accuracy observed, and in a rat cranium imaging experiment. The latter experiment used variation in inspired oxygen (FiO2) to vary the observed hemoglobin and oxygen saturation images. Quantitative agreement was observed between the changes in deoxyhemoglobin values derived from NIR and the changes predicted with blood-oxygen-level-dependent (BOLD) MRI. This system represents the initial stage in what will likely be a larger role for NIR tomography, coupled to MRI, and illustrates that the technological challenges of using continuous-wave broadband data and inclusion of a priori structural information can be met with careful phantom studies.

  5. Developing a multiscale, multi-resolution agent-based brain tumor model by graphics processing units

    Directory of Open Access Journals (Sweden)

    Zhang Le

    2011-12-01

    Full Text Available Abstract Multiscale agent-based modeling (MABM has been widely used to simulate Glioblastoma Multiforme (GBM and its progression. At the intracellular level, the MABM approach employs a system of ordinary differential equations to describe quantitatively specific intracellular molecular pathways that determine phenotypic switches among cells (e.g. from migration to proliferation and vice versa. At the intercellular level, MABM describes cell-cell interactions by a discrete module. At the tissue level, partial differential equations are employed to model the diffusion of chemoattractants, which are the input factors of the intracellular molecular pathway. Moreover, multiscale analysis makes it possible to explore the molecules that play important roles in determining the cellular phenotypic switches that in turn drive the whole GBM expansion. However, owing to limited computational resources, MABM is currently a theoretical biological model that uses relatively coarse grids to simulate a few cancer cells in a small slice of brain cancer tissue. In order to improve this theoretical model to simulate and predict actual GBM cancer progression in real time, a graphics processing unit (GPU-based parallel computing algorithm was developed and combined with the multi-resolution design to speed up the MABM. The simulated results demonstrated that the GPU-based, multi-resolution and multiscale approach can accelerate the previous MABM around 30-fold with relatively fine grids in a large extracellular matrix. Therefore, the new model has great potential for simulating and predicting real-time GBM progression, if real experimental data are incorporated.

  6. Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans.

    Science.gov (United States)

    Nguyen, Jeffrey P; Shipley, Frederick B; Linder, Ashley N; Plummer, George S; Liu, Mochi; Setru, Sagar U; Shaevitz, Joshua W; Leifer, Andrew M

    2016-02-23

    The ability to acquire large-scale recordings of neuronal activity in awake and unrestrained animals is needed to provide new insights into how populations of neurons generate animal behavior. We present an instrument capable of recording intracellular calcium transients from the majority of neurons in the head of a freely behaving Caenorhabditis elegans with cellular resolution while simultaneously recording the animal's position, posture, and locomotion. This instrument provides whole-brain imaging with cellular resolution in an unrestrained and behaving animal. We use spinning-disk confocal microscopy to capture 3D volumetric fluorescent images of neurons expressing the calcium indicator GCaMP6s at 6 head-volumes/s. A suite of three cameras monitor neuronal fluorescence and the animal's position and orientation. Custom software tracks the 3D position of the animal's head in real time and two feedback loops adjust a motorized stage and objective to keep the animal's head within the field of view as the animal roams freely. We observe calcium transients from up to 77 neurons for over 4 min and correlate this activity with the animal's behavior. We characterize noise in the system due to animal motion and show that, across worms, multiple neurons show significant correlations with modes of behavior corresponding to forward, backward, and turning locomotion. PMID:26712014

  7. EMAG2: A 2-arc min resolution Earth Magnetic Anomaly Grid compiled from satellite, airborne, and marine magnetic measurements

    Science.gov (United States)

    Maus, S.; Barckhausen, U.; Berkenbosch, H.; Bournas, N.; Brozena, J.; Childers, V.; Dostaler, F.; Fairhead, J.D.; Finn, C.; von Frese, R.R.B; Gaina, C.; Golynsky, S.; Kucks, R.; Lu, Hai; Milligan, P.; Mogren, S.; Muller, R.D.; Olesen, O.; Pilkington, M.; Saltus, R.; Schreckenberger, B.; Thebault, E.; Tontini, F.C.

    2009-01-01

    A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne magnetic measurements. EMAG2 is a significant update of our previous candidate grid for the World Digital Magnetic Anomaly Map. The resolution has been improved from 3 arc min to 2 arc min, and the altitude has been reduced from 5 km to 4 km above the geoid. Additional grid and track line data have been included, both over land and the oceans. Wherever available, the original shipborne and airborne data were used instead of precompiled oceanic magnetic grids. Interpolation between sparse track lines in the oceans was improved by directional gridding and extrapolation, based on an oceanic crustal age model. The longest wavelengths (>330 km) were replaced with the latest CHAMP satellite magnetic field model MF6. EMAG2 is available at http://geomag.org/models/EMAG2 and for permanent archive at http://earthref.org/ cgi-bin/er.cgi?s=erda.cgi?n=970. ?? 2009 by the American Geophysical Union.

  8. Ultrasensitive Scanning Transmission X-ray Microscopy: Pushing the Limits of Time Resolution and Magnetic Sensitivity

    Science.gov (United States)

    Ohldag, Hendrik

    Understanding magnetic properties at ultrafast timescales is crucial for the development of new magnetic devices. Samples of interest are often thin film magnetic multilayers with thicknesses in the range of a few atomic layers. This fact alone presents a sensitivity challenge in STXM microscopy, which is more suited toward studying thicker samples. In addition the relevant time scale is of the order of 10 ps, which is well below the typical x-ray pulse length of 50 - 100 ps. The SSRL STXM is equipped with a single photon counting electronics that effectively allows using a double lock-in detection at 476MHz (the x-ray pulse frequency) and 1.28MHz (the synchrotron revelation frequency) to provide the required sensitivity. In the first year of operation the excellent spatial resolution, temporal stability and sensitivity of the detection electronics of this microscope has enabled researchers to acquire time resolved images of standing as well as traveling spin waves in a spin torque oscillator in real space as well as detect the real time spin accumulation in non magnetic Copper once a spin polarized current is injected into this material. The total magnetic moment is comparable to that of a single nanocube of magnetic Fe buried under a micron of non-magnetic material.

  9. Fetal brain tumors: Prenatal diagnosis by ultrasound and magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Hérbene; José; Milani; Edward; Araujo; Júnior; Sérgio; Cavalheiro; Patrícia; Soares; Oliveira; Wagner; Jou; Hisaba; Enoch; Quinderé; Sá; Barreto; Maurício; Mendes; Barbosa; Luciano; Marcondes; Nardozza; Antonio; Fernandes; Moron

    2015-01-01

    Congenital central nervous system tumors diagnosed during pregnancy are rare, and often have a poor prognosis. The most frequent type is the teratoma. Use of ultrasound and magnetic resonance image allows the suspicion of brain tumors during pregnancy. However, the definitive diagnosis is only confirmed after birth by histology. The purpose of this mini-review article is to describe the general clinical aspects of intracranial tumors and describe the main fetal brain tumors.

  10. High-field (9.4 T) ~1H magnetic resonance microscopy of mouse brain

    Institute of Scientific and Technical Information of China (English)

    丁广良; 胡红兵; 李丽云; 叶朝辉

    1997-01-01

    The FLASH and STEAM pulse sequences were used to perform the microimaging and localized spectroscopy of brain of living and dead mice, respectively. The phase-shift presaturation approach was used to sup-press water NMR signal. The experimental results show that the differences in localized spectra and MR images of brain between live and dead mice can be observed by means of magnetic resonance microscopy.

  11. Metabolic abnormalities in lobar and subcortical brain regions of abstinent polysubstance users: Magnetic resonance spectroscopic imaging

    OpenAIRE

    Abé, C.; Mon, A.; Hoefer, ME; Durazzo, TC; Pennington, DL; Schmidt, TP; Meyerhoff, DJ

    2013-01-01

    Aims: The aim of the study was to explore neurometabolic and associated cognitive characteristics of patients with polysubstance use (PSU) in comparison with patients with predominant alcohol use using proton magnetic resonance spectroscopy. Methods: Brain metabolite concentrations were examined in lobar and subcortical brain regions of three age-matched groups: 1-monthabstinent alcohol-dependent PSU, 1-month-abstinent individuals dependent on alcohol alone (ALC) and light drinking controls (...

  12. Review: magnetic resonance imaging of male/female differences in human adolescent brain anatomy

    OpenAIRE

    Giedd Jay N; Raznahan Armin; Mills Kathryn L; Lenroot Rhoshel K

    2012-01-01

    Abstract Improvements in neuroimaging technologies, and greater access to their use, have generated a plethora of data regarding male/female differences in the developing brain. Examination of these differences may shed light on the pathophysiology of the many illnesses that differ between the sexes and ultimately lead to more effective interventions. In this review, we attempt to synthesize the anatomic magnetic resonance imaging (MRI) literature of male/female brain differences with emphasi...

  13. Brain white matter lesions detected by magnetic resosnance imaging are associated with balance and gait speed

    OpenAIRE

    John M Starr; Leaper, S A; Murray, A D; Lemmon, H A; Staff, R T; Deary, Ian J.; Whalley, Lawrence J.

    2003-01-01

    Objective: To investigate the relations between premorbid and current mental ability, mood, and white matter signal abnormalities detected by T2 weighted brain magnetic resonance imaging (MRI) and impairment of balance and mobility in older adults. Methods: 97 subjects from the Aberdeen 1921 birth cohort underwent brain MRI, evaluation of balance, and measurement of gait speed. White matter hyperintensities detected on T2 weighted MRI scans were rated by three independent raters on three ...

  14. Increased blood–brain barrier permeability in type II diabetes demonstrated by gadolinium magnetic resonance imaging

    OpenAIRE

    Starr, J; Wardlaw, J; Ferguson, K; MacLullich, A; Deary, I; Marshall, I

    2003-01-01

    Objectives: Patients with type II diabetes are at increased risk of cognitive impairment. The retinal and renal complications of diabetes follow microvascular damage permitting small arterioles to leak, hence the cerebral damage might also follow loss of blood–brain barrier (BBB) integrity. Magnetic resonance (MR) brain imaging with intravenous gadolinium (Gd) diethylenetriamine pentaacetic acid (Gd-DTPA) was used to identify increased BBB permeability.

  15. Cerebrospinal fluid metabolic profiles in multiple sclerosis and degenerative dementias obtained by high resolution proton magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    We have analyzed the cerebrospinal fluid (CSF) of 19 patients with multiple sclerosis (MS), 12 patients with degenerative dementia and 17 control patients using in vitro high resolution proton magnetic resonance spectroscopy (MRS) at 400 MHz. The CSF metabolic profile is slightly modified in MS patients (increased lactate and fructose concentrations, decreased creatinine and phenylalanine concentrations) and is not correlated with the intensity of the intrathecal inflammation. Proton MRS of CSF does not differentiate relapsing-remitting MS and primary progressive MS. We have not detected any specific abnormal resonance in native or lyophilized CSF. The CSF metabolic profile of demented patients is much more altered (increased concentration of lactate, pyruvate, alanine, lysine, valine, leucine-isoleucine, tyrosine, glutamine) and is in agreement with a brain oxidative metabolism impairment as already described in Alzheimer's disease. Unassigned abnormal but non specific or constant resonances have been detected on MR spectra of demented patients. CSF inositol concentration is also increased in the CSF of patients with Alzheimer's disease. In vitro high resolution proton MRS of the CSF constitutes a new and original way to explore CSF for the differential and/or early diagnosis of dementias, as a complement to in vivo proton cerebral MRS. (authors). 22 refs., 4 figs., 2 tabs

  16. Alzheimer's Disease Detection in Brain Magnetic Resonance Images Using Multiscale Fractal Analysis

    International Nuclear Information System (INIS)

    We present a new automated system for the detection of brain magnetic resonance images (MRI) affected by Alzheimer's disease (AD). The MRI is analyzed by means of multiscale analysis (MSA) to obtain its fractals at six different scales. The extracted fractals are used as features to differentiate healthy brain MRI from those of AD by a support vector machine (SVM) classifier. The result of classifying 93 brain MRIs consisting of 51 images of healthy brains and 42 of brains affected by AD, using leave-one-out cross-validation method, yielded 99.18% ± 0.01 classification accuracy, 100% sensitivity, and 98.20% ± 0.02 specificity. These results and a processing time of 5.64 seconds indicate that the proposed approach may be an efficient diagnostic aid for radiologists in the screening for AD

  17. On the Voxel Size and Magnetic Field Strength Dependence of Spectral Resolution in MR Spectroscopy

    OpenAIRE

    Fleysher, Roman; Fleysher, Lazar; Liu, Songtao; Gonen, Oded

    2008-01-01

    While the inherent low sensitivity of in vivo MR spectroscopy motivated a trend towards higher magnetic fields, B0, it since has become apparent that this increase does not seem to translate into the anticipated improvement in spectral resolution. This is attributed to the decrease of the transverse relaxation time, T2*, in vivo due to macro- and mesoscopic tissue susceptibility. Using spectral contrast to noise ratio arguments we show that if in biological systems the linewidth (on the frequ...

  18. High-resolution Magnetic Resonance Imaging analysis of breast cancer xenograft on the chick chorioallantoic membrane

    OpenAIRE

    ZUO, ZHI

    2015-01-01

    In this thesis an age-adapted cooling regime for immobilization of the chick embryo is proposed. Reliable immobilization completely avoided motion artifacts, enabling high resolution magnetic resonance imaging (MRI) of the chicken embryo and also tumor xenograft on the chorioallantoic membrane (CAM). Tumor growth monitoring was firstly evaluated after xenotransplantation of MDA-MB-231 cells on the CAM. Tumor volumes were monitored from day 4 to day 9 after grafting applying a T2-weighted R...

  19. STUDY OF BRAIN TUMOURS BY NOVE L MAGNETIC RESONANCE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Mohammad Shamim

    2015-01-01

    Full Text Available In the present study , thirty patients in the age range of 22 to 63 years of age were included after being diagnosed to be having brain tumour on CT scan or conventional MRI. In addition DWI , MRS , and PWI were carried out i n these patients. All the patients with suspicious malignant lesions were then subjected to FDG - PET examination . Histopathological correlation was obtained in all the patients to serve as gold standard against which other modalities will be assessed for th eir sensitivity , specificity , positive predictive value , negative predictive value and diagnostic accuracy. Out of thirty patients selected for this study , twenty cases were found to be malignant and ten cases were benign on Histopathological evaluation. Majority of malignant lesions were glioblastoma multiforme. Amongst benign cases , majorities were meningioma , one was a Granulomatous lesion and one was a benign cystic lesion. MRI including the novel techniques showed high sensitivity and spe cificity in identifying malignant brain lesions and has a future role in better characterization of brain tumours. Wherever available , it should be integrated in routine workup of patients presenting with brain tumours or for follow up of patients undergon e surgery / adjuvant chemotherapy.

  20. Multi circular-cavity surface coil for magnetic resonance imaging of monkey's brain at 4 Tesla

    Science.gov (United States)

    Osorio, A. I.; Solis-Najera, S. E.; Vázquez, F.; Wang, R. L.; Tomasi, D.; Rodriguez, A. O.

    2014-11-01

    Animal models in medical research has been used to study humans diseases for several decades. The use of different imaging techniques together with different animal models offers a great advantage due to the possibility to study some human pathologies without the necessity of chirurgical intervention. The employ of magnetic resonance imaging for the acquisition of anatomical and functional images is an excellent tool because its noninvasive nature. Dedicated coils to perform magnetic resonance imaging experiments are obligatory due to the improvement on the signal-to-noise ratio and reduced specific absorption ratio. A specifically designed surface coil for magnetic resonance imaging of monkey's brain is proposed based on the multi circular-slot coil. Numerical simulations of the magnetic and electric fields were also performed using the Finite Integration Method to solve Maxwell's equations for this particular coil design and, to study the behavior of various vector magnetic field configurations and specific absorption ratio. Monkey's brain images were then acquired with a research-dedicated magnetic resonance imaging system at 4T, to evaluate the anatomical images with conventional imaging sequences. This coil showed good quality images of a monkey's brain and full compatibility with standard pulse sequences implemented in research-dedicated imager.

  1. Focused Azimuthally E-Polarized Vector Beam and Spatial Magnetic Resolution below the Diffraction Limit

    CERN Document Server

    Veysi, Mehdi; Capolino, Filippo

    2016-01-01

    An azimuthally E-polarized vector beam (AEVB) has a salient feature that it contains a magnetic-dominant region within which electric field has a null and longitudinal magnetic field is maximum. Fresnel diffraction theory and plane-wave spectral (PWS) calculations are applied to quantify the field features of such a beam upon focusing through a lens. The diffraction-limited full width at half maximum (FWHM) of the beams longitudinal magnetic field intensity profile and complementary FWHM (CFWHM) of the beam's annular-shaped total electric field intensity profile are calculated at the lens's focal plane as a function of the lens's paraxial focal distance. Subsequently, we demonstrate, for the first time, that a very high resolution magnetic field at optical frequency with the total magnetic field FWHM of 0.23{\\lambda}(magnetic field spot size of 0.04{\\lambda}^2) can be achieved by placing a subwavelength dense dielectric Mie scatterer in the minimum-waist plane of a self-standing converging AEVB. The theory sh...

  2. High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

    International Nuclear Information System (INIS)

    The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy. Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning parameters targeted at optimizing spatial resolution. Direct comparisons between 3 and 7 T were performed in two additional subjects using the finalized sequences (3 T: T2, PD, MPRAGE, SWAN; 7 T: 3D T2, MPRAGE, SWI, MP2RAGE). Artifacts and the depiction of structures were evaluated by two neuroradiologists using a standardized score sheet. Sequences could be established for high-resolution 7 T imaging even in caudal cranial areas. High in-plane resolution T2, PD, and SWI images provided depiction of inner brain stem structures such as pons fibers, raphe, reticular formation, nerve roots, and periaqueductal gray. MPRAGE and MP2RAGE provided clear depiction of the CNs. 3D T2 images improved depiction of inner brain structure in comparison to T2 images at 3 T. Although the 7-T SWI sequence provided improved contrast to some inner structures, extended areas were influenced by artifacts due to image disturbances from susceptibility differences. Seven-tesla imaging of basal brain areas is feasible and might have significant impact on detection and diagnosis in patients with specific diseases, e.g., trigeminal pain related to affection of the nerve root. Some inner brain stem structures can be depicted at 3 T, but certain sequences at 7 T, in particular 3D SPACE T2, are superior in producing anatomical in vivo images of deep brain stem structures. (orig.)

  3. High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

    Energy Technology Data Exchange (ETDEWEB)

    Gizewski, Elke R. [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Maderwald, Stefan [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Linn, Jennifer; Bochmann, Katja [LMU Munich, Department of Neuroradiology, Munich (Germany); Dassinger, Benjamin [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Justus-Liebig-University Giessen, Department of Neuroradiology, Giessen (Germany); Forsting, Michael [University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Ladd, Mark E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2014-03-15

    The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy. Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning parameters targeted at optimizing spatial resolution. Direct comparisons between 3 and 7 T were performed in two additional subjects using the finalized sequences (3 T: T2, PD, MPRAGE, SWAN; 7 T: 3D T2, MPRAGE, SWI, MP2RAGE). Artifacts and the depiction of structures were evaluated by two neuroradiologists using a standardized score sheet. Sequences could be established for high-resolution 7 T imaging even in caudal cranial areas. High in-plane resolution T2, PD, and SWI images provided depiction of inner brain stem structures such as pons fibers, raphe, reticular formation, nerve roots, and periaqueductal gray. MPRAGE and MP2RAGE provided clear depiction of the CNs. 3D T2 images improved depiction of inner brain structure in comparison to T2 images at 3 T. Although the 7-T SWI sequence provided improved contrast to some inner structures, extended areas were influenced by artifacts due to image disturbances from susceptibility differences. Seven-tesla imaging of basal brain areas is feasible and might have significant impact on detection and diagnosis in patients with specific diseases, e.g., trigeminal pain related to affection of the nerve root. Some inner brain stem structures can be depicted at 3 T, but certain sequences at 7 T, in particular 3D SPACE T2, are superior in producing anatomical in vivo images of deep brain stem structures. (orig.)

  4. Measuring stellar magnetic fields from high resolution spectroscopy of near-infrared lines

    Science.gov (United States)

    Leone, F.; Vacca, W. D.; Stift, M. J.

    2003-10-01

    Zeeman splitting of otherwise degenerate levels provides a straight-forward method of measuring stellar magnetic fields. In the optical, the relative displacements of the Zeeman components are quite small compared to the rotational line broadening, and therefore observations of Zeeman splitting are usually possible only for rather strong magnetic fields in very slowly rotating stars. However, the magnitude of the Zeeman splitting is proportional to the square of the wavelength, whereas rotational line broadening mechanisms are linear in wavelength; therefore, there is a clear advantage in using near-infrared spectral lines to measure surface stellar magnetic fields. We have obtained high resolution (R >= 25 000) spectra in the 15 625-15 665 Å region for two magnetic chemically peculiar stars, viz. HD 176232 and HD 201601, and for the suspected magnetic chemically peculiar star HD 180583, as part of a pilot study aimed at determining the accuracy with which we can measure stellar magnetic fields using the Zeeman splitting of near-infrared lines. We confirm that in principle the magnetic field strength can be estimated from the magnetic intensification of spectral lines, i.e. the increase in equivalent width of a line over the zero-field value. However, due to line blending as well as the dependence of this intensification on abundance and field geometry, accurate estimates of the magnetic field strengths can be obtained only by modelling the line profiles by means of spectral synthesis techniques. Using this approach, we find a 1.4 kG magnetic field modulus in HD 176132 and an upper limit of 0.2 kG in HD 180583. The very weak infrared lines in the spectrum of HD 201601 are consistent with a 3.9 kG field modulus estimated from the splitting of the Fe II 6149.258 Å line seen in an optical spectrum. Finally, we would like to draw attention to the fact that there are no sufficiently detailed and reliable atomic line lists available for the near-infrared region that

  5. Stellar magnetic field parameters from a Bayesian analysis of high-resolution spectropolarimetric observations

    CERN Document Server

    Petit, V

    2011-01-01

    In this paper we describe a Bayesian statistical method designed to infer the magnetic properties of stars observed using high-resolution circular spectropolarimetry in the context of large surveys. This approach is well suited for analysing stars for which the stellar rotation period is not known, and therefore the rotational phases of the observations are ambiguous. The model assumes that the magnetic observations correspond to a dipole oblique rotator, a situation commonly encountered in intermediate and high-mass stars. Using reasonable assumptions regarding the model parameter prior probability density distributions, the Bayesian algorithm determines the posterior probability densities corresponding to the surface magnetic field geometry and strength by performing a comparison between the observed and computed Stokes V profiles. Based on the results of numerical simulations, we conclude that this method yields a useful estimate of the surface dipole field strength based on a small number (i.e. 1 or 2) of...

  6. Neural basis for brain responses to TV commercials: a high-resolution EEG study.

    Science.gov (United States)

    Astolfi, Laura; De Vico Fallani, F; Cincotti, F; Mattia, D; Bianchi, L; Marciani, M G; Salinari, S; Colosimo, A; Tocci, A; Soranzo, R; Babiloni, F

    2008-12-01

    We investigated brain activity during the observation of TV commercials by tracking the cortical activity and the functional connectivity changes in normal subjects. The aim was to elucidate if the TV commercials that were remembered by the subjects several days after their first observation elicited particular brain activity and connectivity compared with those generated during the observation of TV commercials that were quickly forgotten. High-resolution electroencephalogram (EEG) recordings were performed in a group of healthy subjects and the cortical activity during the observation of TV commercials was evaluated in several regions of interest coincident with the Brodmann areas (BAs). The patterns of cortical connectivity were obtained in the four principal frequency bands, Theta (3-7 Hz), Alpha (8-12 Hz), Beta (13-30 Hz), Gamma (30-40 Hz) and the directed influences between any given pair of the estimated cortical signals were evaluated by use of a multivariate spectral technique known as partial directed coherence. The topology of the cortical networks has been identified with tools derived from graph theory. Results suggest that the cortical activity and connectivity elicited by the viewing of the TV commercials that were remembered by the experimental subjects are markedly different from the brain activity elicited during the observation of the TV commercials that were forgotten. In particular, during the observation of the TV commercials that were remembered, the amount of cortical spectral activity from the frontal areas (BA 8 and 9) and from the parietal areas (BA 5, 7, and 40) is higher compared with the activity elicited by the observation of TV commercials that were forgotten. In addition, network analysis suggests a clear role of the parietal areas as a target of the incoming flow of information from all the other parts of the cortex during the observation of TV commercials that have been remembered. The techniques presented here shed new light on

  7. Neural basis for brain responses to TV commercials: a high-resolution EEG study.

    Science.gov (United States)

    Astolfi, Laura; De Vico Fallani, F; Cincotti, F; Mattia, D; Bianchi, L; Marciani, M G; Salinari, S; Colosimo, A; Tocci, A; Soranzo, R; Babiloni, F

    2008-12-01

    We investigated brain activity during the observation of TV commercials by tracking the cortical activity and the functional connectivity changes in normal subjects. The aim was to elucidate if the TV commercials that were remembered by the subjects several days after their first observation elicited particular brain activity and connectivity compared with those generated during the observation of TV commercials that were quickly forgotten. High-resolution electroencephalogram (EEG) recordings were performed in a group of healthy subjects and the cortical activity during the observation of TV commercials was evaluated in several regions of interest coincident with the Brodmann areas (BAs). The patterns of cortical connectivity were obtained in the four principal frequency bands, Theta (3-7 Hz), Alpha (8-12 Hz), Beta (13-30 Hz), Gamma (30-40 Hz) and the directed influences between any given pair of the estimated cortical signals were evaluated by use of a multivariate spectral technique known as partial directed coherence. The topology of the cortical networks has been identified with tools derived from graph theory. Results suggest that the cortical activity and connectivity elicited by the viewing of the TV commercials that were remembered by the experimental subjects are markedly different from the brain activity elicited during the observation of the TV commercials that were forgotten. In particular, during the observation of the TV commercials that were remembered, the amount of cortical spectral activity from the frontal areas (BA 8 and 9) and from the parietal areas (BA 5, 7, and 40) is higher compared with the activity elicited by the observation of TV commercials that were forgotten. In addition, network analysis suggests a clear role of the parietal areas as a target of the incoming flow of information from all the other parts of the cortex during the observation of TV commercials that have been remembered. The techniques presented here shed new light on

  8. Magnetic resonance imaging of brain in cardiogenic insults

    International Nuclear Information System (INIS)

    MRI characteristic of stroke in patients with different forms of atrial fibrillation with the account of main vascular risk factors was described. The most frequent type of MRI picture in cardio embolic stroke is a wedge-shaped area in the cortical subcortical portions of the frontoparietal or patient temporal lobe. Hemorrhagic transformation of the brain infarct was diagnosed in 33,3% of the patient with cardio embolic insult. Small lacunar infarcts were visualized mainly in the patients with arterial hypertension

  9. Brain activation and inhibition after acupuncture at Taichong and Taixi: resting-state functional magnetic resonance imaging

    OpenAIRE

    Shao-qun Zhang; Yan-jie Wang; Ji-ping Zhang; Jun-qi Chen; Chun-xiao Wu; Zhi-peng Li; Jia-rong Chen; Huai-liang Ouyang; Yong Huang; Chun-zhi Tang

    2015-01-01

    Acupuncture can induce changes in the brain. However, the majority of studies to date have focused on a single acupoint at a time. In the present study, we observed activity changes in the brains of healthy volunteers before and after acupuncture at Taichong (LR3) and Taixi (KI3) using resting-state functional magnetic resonance imaging. Fifteen healthy volunteers underwent resting-state functional magnetic resonance imaging of the brain 15 minutes before acupuncture, then received acupunctur...

  10. Quantification of brain metabolites in amyotrophic lateral sclerosis by localized proton magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Gredal, O; Rosenbaum, S; Topp, S;

    1997-01-01

    We performed proton magnetic resonance spectroscopy (1H-MRS) in patients with motor neuron disease (MND) to determine the absolute in vivo concentrations in the brain of the metabolites N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr/PCr). We examined the spectra acquired from a 20 x 20 x...

  11. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves

    DEFF Research Database (Denmark)

    Rossini, P M; Burke, D; Chen, R;

    2015-01-01

    These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some ...

  12. Time resolved dosimetry of human brain exposed to low frequency pulsed magnetic fields

    Science.gov (United States)

    Paffi, Alessandra; Camera, Francesca; Lucano, Elena; Apollonio, Francesca; Liberti, Micaela

    2016-06-01

    An accurate dosimetry is a key issue to understanding brain stimulation and related interaction mechanisms with neuronal tissues at the basis of the increasing amount of literature revealing the effects on human brain induced by low-level, low frequency pulsed magnetic fields (PMFs). Most literature on brain dosimetry estimates the maximum E field value reached inside the tissue without considering its time pattern or tissue dispersivity. Nevertheless a time-resolved dosimetry, accounting for dispersive tissues behavior, becomes necessary considering that the threshold for an effect onset may vary depending on the pulse waveform and that tissues may filter the applied stimulatory fields altering the predicted stimulatory waveform’s size and shape. In this paper a time-resolved dosimetry has been applied on a realistic brain model exposed to the signal presented in Capone et al (2009 J. Neural Transm. 116 257–65), accounting for the broadband dispersivity of brain tissues up to several kHz, to accurately reconstruct electric field and current density waveforms inside different brain tissues. The results obtained by exposing the Duke’s brain model to this PMF signal show that the E peak in the brain is considerably underestimated if a simple monochromatic dosimetry is carried out at the pulse repetition frequency of 75 Hz.

  13. Structural Image Analysis of the Brain in Neuropsychology Using Magnetic Resonance Imaging (MRI) Techniques.

    Science.gov (United States)

    Bigler, Erin D

    2015-09-01

    Magnetic resonance imaging (MRI) of the brain provides exceptional image quality for visualization and neuroanatomical classification of brain structure. A variety of image analysis techniques provide both qualitative as well as quantitative methods to relate brain structure with neuropsychological outcome and are reviewed herein. Of particular importance are more automated methods that permit analysis of a broad spectrum of anatomical measures including volume, thickness and shape. The challenge for neuropsychology is which metric to use, for which disorder and the timing of when image analysis methods are applied to assess brain structure and pathology. A basic overview is provided as to the anatomical and pathoanatomical relations of different MRI sequences in assessing normal and abnormal findings. Some interpretive guidelines are offered including factors related to similarity and symmetry of typical brain development along with size-normalcy features of brain anatomy related to function. The review concludes with a detailed example of various quantitative techniques applied to analyzing brain structure for neuropsychological outcome studies in traumatic brain injury.

  14. Noninvasive detection of temozolomide in brain tumor xenografts by magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Kato, Y.; Holm, David Alberg; Okollie, B.;

    2010-01-01

    MG human brain cancer. Dynamic magnetic resonance imaging (MRI) with the low-molecular-weight contrast agent, gadolinium diethylenetriaminepentaacetic acid (GdDTPA), was used to evaluate tumor vascular parameters. Carbon-13-labeled TMZ ([C-13]TMZ, 99%) was intraperitoneally administered at a dose...... experiments demonstrated slower recovery of MRI signal following an intravenous bolus injection of GdDTPA, higher vascular flow and volume obtained by T-2*-weighted MRI, as well as enhanced uptake of the contrast agent in the brain tumor compared with normal brain detected by T-1-weighted MRI. These data...... detection of drug directly in the tumor can be critically important for accessing, predicting, and eventually improving effectiveness of therapy. In this study, in vivo magnetic resonance spectroscopy (MRS) was used to detect an anticancer agent, temozolomide (TMZ), in vivo in murine xenotransplants of U87...

  15. Application of magnetic resonance spectroscopy in the differentiation of high-grade brain neoplasm and inflammatory brain lesions

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz-Filho, Jose Roberto Lopes; Santana-Netto, Pedro Vieira; Sgnolf, Aline [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Image Dept.], e-mail: jrl.ferraz@terra.com.br; Rocha-Filho, Jose Alves; Mauad, Fernando [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Radiology Dept.; Sanches, Rafael Angelo [FAMERP Medical School, Sao Jose do Rio Preto SP (Brazil). Imaging Dept.

    2009-06-15

    This study aims at evaluating the application of magnetic resonance spectroscopy (MRS) in the differential diagnosis of brain tumors and inflammatory brain lesions. The examinations of 81 individuals, who performed brain MRS and were retrospectively analyzed. The patients with ages between 10 and 80 years old, were divided into two groups. Group A consisted of 42 individuals with diagnoses of cerebral toxoplasmosis and Group B was formed of 39 individuals with diagnosis of glial neoplasms. On analyzing the ROC curve, the discriminatory boundary for the Cho/Cr ratio between inflammatory lesions and tumors was 1.97 and for the NAA/Cr ratio it was 1.12. RMS is an important method useful in the distinction of inflammatory brain lesions and high-degree tumors when the Cho/Cr ratio is greater than 1.97 and the NAA/Cr ratio is less than 1.12. And so this method is important in the planning of treatment and monitoring of the therapeutic efficiency. (author)

  16. High-resolution, in vivo magnetic resonance imaging of Drosophila at 18.8 Tesla.

    Directory of Open Access Journals (Sweden)

    Brian Null

    Full Text Available High resolution MRI of live Drosophila was performed at 18.8 Tesla, with a field of view less than 5 mm, and administration of manganese or gadolinium-based contrast agents. This study demonstrates the feasibility of MR methods for imaging the fruit fly Drosophila with an NMR spectrometer, at a resolution relevant for undertaking future studies of the Drosophila brain and other organs. The fruit fly has long been a principal model organism for elucidating biology and disease, but without capabilities like those of MRI. This feasibility marks progress toward the development of new in vivo research approaches in Drosophila without the requirement for light transparency or destructive assays.

  17. The magnetic fields of Ap stars from high resolution Stokes IQUV spectropolarimetry

    Science.gov (United States)

    Silvester, James

    In this thesis we describe the acquisition of high resolution time resolved spectropolarimetric observations of 7 (bright and well understood) Ap stars in Stokes IQUV using the ESPaDOnS and Narval spectropolarimeters at the Canada-France-Hawaii Telescope and the 2m Telescope Bernard Lyot at Pic du Midi Observatory. We compare these observations with those obtained a decade earlier using the MuSiCoS spectropolarimeter to confirm consistency with the older data and provide evidence that both ESPaDOnS and Narval perform as expected in all Stokes parameters. We demonstrate that our refined longitudinal magnetic field and linear polarisation measurements for these 7 stars are of much greater quality than was previously obtained with MuSiCoS and that the global magnetic properties of these stars are stable over a long timescale. The ultimate aim of these new data is to provide a basis from which mapping of both the magnetic field and abundance structures can be performed on our target stars. We then describe magnetic field mapping of the Ap star alpha 2 CVn using these data. This mapping is achieved with the use of tomographic inversion of Doppler-broadened Stokes IQUV profiles of a large variety of spectral lines using the INVERS10 Magnetic Doppler imaging code. We show that not only are the new magnetic field maps of alpha 2 CVn consistent with a previous generation of maps of alpha 2 CVn, but that the same magnetic field topology can be derived from a variety of atomic line sets. This indicates that the magnetic field we derive for alpha2 CVn is a realistic representation of the star's true magnetic topology. Finally we investigate surface abundance structures for alpha 2 CVn for various chemical elements. We investigate the correlation between the location of these abundance features and the magnetic field of alpha 2 CVn. We will demonstrate that whilst the magnetic field plays a role in the formation of abundance structures, the current theoretical framework does

  18. Multi-resolution Statistical Analysis of Brain Connectivity Graphs in Preclinical Alzheimer's Disease

    Science.gov (United States)

    Kim, Won Hwa; Adluru, Nagesh; Chung, Moo K.; Okonkwo, Ozioma C.; Johnson, Sterling C.; Bendlin, Barbara; Singh, Vikas

    2015-01-01

    There is significant interest, both from basic and applied research perspectives, in understanding how structural/functional connectivity changes can explain behavioral symptoms and predict decline in neurodegenerative diseases such as Alzheimer's disease (AD). The first step in most such analyses is to encode the connectivity information as a graph; then, one may perform statistical inference on various ‘global’ graph theoretic summary measures (e.g., modularity, graph diameter) and/or at the level of individual edges (or connections). For AD in particular, clear differences in connectivity at the dementia stage of the disease (relative to healthy controls) have been identified. Despite such findings, AD-related connectivity changes in preclinical disease remain poorly characterized. Such preclinical datasets are typically smaller and group differences are weaker. In this paper, we propose a new multi-resolution method for performing statistical analysis of connectivity networks/graphs derived from neuroimaging data. At the high level, the method occupies the middle ground between the two contrasts — that is, to analyze global graph summary measures (global) or connectivity strengths or correlations for individual edges similar to voxel based analysis (local). Instead, our strategy derives a Wavelet representation at each primitive (connection edge) which captures the graph context at multiple resolutions. We provide extensive empirical evidence of how this framework offers improved statistical power by analyzing two distinct AD datasets. Here, connectivity is derived from diffusion tensor magnetic resonance images by running a tractography routine. We first present results showing significant connectivity differences between AD patients and controls that were not evident using standard approaches. Later, we show results on populations that are not diagnosed with AD but have a positive family history risk of AD where our algorithm helps in identifying

  19. Use of High resolution 3D Diffusion tensor imaging to study brain white matter development in live neonatal rats

    Directory of Open Access Journals (Sweden)

    Yu eCai

    2011-10-01

    Full Text Available High resolution diffusion tensor imaging (DTI can provide important information on brain development, yet it is challenging in live neonatal rats due to the small size of neonatal brain and motion-sensitive nature of DTI. Imaging in live neonatal rats has clear advantages over fixed brain scans, as longitudinal and functional studies would be feasible to understand neuro-developmental abnormalities. In this study, we developed imaging strategies that can be used to obtain high resolution 3D DTI images in live neonatal rats at postnatal day 5 (PND5 and postnatal day 14 (PND14, using only 3 hours of imaging acquisition time. An optimized 3D DTI pulse sequence and appropriate animal setup to minimize physiological motion artifacts are the keys to successful high resolution 3D DTI imaging. Thus, a 3D RARE DTI sequence with twin navigator echoes was implemented to accelerate imaging acquisition time and minimize motion artifacts. It has been suggested that neonatal mammals possess a unique ability to tolerate mild to moderate hypothermia and hypoxia without long term impact. Thus, we additionally utilized this ability to minimize motion artifacts in MR images by carefully suppressing the respiratory rate to around 15/min for PND5 and 30/min for PND14 using mild to moderate hypothermia. These imaging strategies have been successfully implemented to study how the effect of cocaine exposure in dams might affect brain development in their rat pups. Image quality resulting from this in vivo DTI study was comparable to ex vivo scans. FA values were also similar between the live and fixed brain scans. The capability of acquiring high quality in vivo DTI imaging offers a valuable opportunity to study many neurological disorders in brain development in an authentic living environment.

  20. Magnetic resonance imaging of the brain in congenital cytomegalovirus infection

    International Nuclear Information System (INIS)

    The children (age 2 months to 8 years) with a congenital cytomegalovirus (CMV) infection were studied by magnetic resonance imaging (MRI) using a 2.35 Tesla magnet. CMV infection was confirmed by serological investigations and virus culture in the neonatal period. Nine children had severe mental retardation and cerebral palsy, 1 patient suffered from microcephaly, ataxia and deafness. The cranial MRI examination showed the following abnormalities (N): Dilated lateral ventricles (10) and subarachnoid space (8), oligo/pacgyria (8), delayed/pathological myelination (7), paraventricular cysts (6), intra-cerebral calcification (1). This lack of sensitivity for calcification is explainable by the basic principles of MRI. The paraventricular cystic lesions were adjacent ot the occipital horns of the lateral ventricles and separated only by a thin membrane. This finding might represent a 'new sign' for congenital CMV infection in MRI examinations, being characteristic but nevertheless nonspecific, like calcification in CT. (orig.)

  1. Magnetic resonance imaging of the brain in congenital cytomegalovirus infection

    Energy Technology Data Exchange (ETDEWEB)

    Boesch, C.; Issakainen, J.; Kewitz, G.; Kikinis, R.; Martin, E.; Boltshauser, E.

    1989-01-01

    The children (age 2 months to 8 years) with a congenital cytomegalovirus (CMV) infection were studied by magnetic resonance imaging (MRI) using a 2.35 Tesla magnet. CMV infection was confirmed by serological investigations and virus culture in the neonatal period. Nine children had severe mental retardation and cerebral palsy, 1 patient suffered from microcephaly, ataxia and deafness. The cranial MRI examination showed the following abnormalities (N): Dilated lateral ventricles (10) and subarachnoid space (8), oligo/pacgyria (8), delayed/pathological myelination (7), paraventricular cysts (6), intra-cerebral calcification (1). This lack of sensitivity for calcification is explainable by the basic principles of MRI. The paraventricular cystic lesions were adjacent ot the occipital horns of the lateral ventricles and separated only by a thin membrane. This finding might represent a 'new sign' for congenital CMV infection in MRI examinations, being characteristic but nevertheless nonspecific, like calcification in CT.

  2. Fast Human Brain Magnetic Resonance Responses Associated With Epileptiform Spikes

    OpenAIRE

    Sundaram, Padmavathi; Wells, William M.; Mulkern, Robert V.; Bubrick, Ellen J.; Bromfield, Edward B.; Münch, Mirjam; Orbach, Darren B.

    2010-01-01

    Neuronal currents produce local electromagnetic fields that can potentially modulate the phase of the magnetic resonance signal and thus provide a contrast mechanism tightly linked to neuronal activity. Previous work has demonstrated the feasibility of direct MRI of neuronal activity in phantoms and cell culture, but in vivo efforts have yielded inconclusive, conflicting results. The likelihood of detecting and validating such signals can be increased with (i) fast gradient-echo echo-planar i...

  3. An ultra­high field Magnetic Resonance Spectroscopy study of post exercise brain lactate, glutamate and glutamine change in the human brain.

    Directory of Open Access Journals (Sweden)

    Andrea eDennis

    2015-12-01

    Full Text Available During strenuous exercise there is a progressive increase in lactate uptake and metabolism into the brain as workload and plasma lactate levels increase. Although it is now widely accepted that the brain can metabolise lactate, few studies have directly measured brain lactate following vigorous exercise. Here, we used ultra-high field Magnetic Resonance Spectroscopy of the brain to obtain static measures of brain lactate, as well as brain glutamate and glutamine after vigorous exercise. The aims of our experiment were to (a track the changes in brain lactate following recovery from exercise and, (b to simultaneously measure the signals from brain glutamate and glutamine. The results of our experiment showed that vigorous exercise resulted in a significant increase in brain lactate. Furthermore, both glutamate and glutamine were successfully resolved, and as expected, although contrary to some previous reports, we did not observe any significant change in either amino acid after exercise. We did however observe a negative correlation between glutamate and a measure of fitness. These results support the hypothesis that peripherally-derived lactate is taken up by the brain when available. Our data additionally highlight the potential of ultra-high field magnetic resonance spectroscopy as a non-invasive way of measuring multiple brain metabolite changes with exercise.

  4. Influence of type 2 diabetes on brain volumes and changes in brain volumes: Results from the Women's Health Initiative Magnetic Resonance Imaging Studies

    OpenAIRE

    Espeland, MA; Bryan, RN; Goveas, JS; Robinson, JG; Siddiqui, MS; Liu, S.; Hogan, PE; Casanova, R; Coker, LH; Yaffe, K.; Masaki, K.; Rossom, R; Resnick, SM

    2012-01-01

    OBJECTIVE - To study how type 2 diabetes adversely affects brain volumes, changes in volume, and cognitive function. RESEARCH DESIGN AND METHODS - Regional brain volumes and ischemic lesion volumes in 1,366 women, aged 72-89 years, were measured with structural brain magnetic resonance imaging (MRI). Repeat scans were collected an average of 4.7 years later in 698 women. Cross-sectional differences and changes with time between women with and without diabetes were compared. Relationships that...

  5. Low-frequency transcranial magnetic stimulation is beneifcial for enhancing synaptic plasticity in the aging brain

    Institute of Scientific and Technical Information of China (English)

    Zhan-chi Zhang; Feng Luan; Chun-yan Xie; Dan-dan Geng; Yan-yong Wang; Jun Ma

    2015-01-01

    In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz) ameliorates synaptic plasticity and spatial cognitive deifcits in learning-im-paired mice. However, the mechanisms by which this treatment improves these deifcits during normal aging are still unknown. Therefore, the current study investigated the effects of tran-scranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, syn-aptophysin and growth-associated protein 43 (both synaptic markers), to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcra-nial magnetic stimulation with low intensity (110%average resting motor threshold intensity, 1 Hz) increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippo-campus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this reg-ulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  6. Low-frequency transcranial magnetic stimulation is beneficial for enhancing synaptic plasticity in the aging brain

    Directory of Open Access Journals (Sweden)

    Zhan-chi Zhang

    2015-01-01

    Full Text Available In the aging brain, cognitive function gradually declines and causes a progressive reduction in the structural and functional plasticity of the hippocampus. Transcranial magnetic stimulation is an emerging and novel neurological and psychiatric tool used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency transcranial magnetic stimulation (≤1 Hz ameliorates synaptic plasticity and spatial cognitive deficits in learning-impaired mice. However, the mechanisms by which this treatment improves these deficits during normal aging are still unknown. Therefore, the current study investigated the effects of transcranial magnetic stimulation on the brain-derived neurotrophic factor signal pathway, synaptic protein markers, and spatial memory behavior in the hippocampus of normal aged mice. The study also investigated the downstream regulator, Fyn kinase, and the downstream effectors, synaptophysin and growth-associated protein 43 (both synaptic markers, to determine the possible mechanisms by which transcranial magnetic stimulation regulates cognitive capacity. Transcranial magnetic stimulation with low intensity (110% average resting motor threshold intensity, 1 Hz increased mRNA and protein levels of brain-derived neurotrophic factor, tropomyosin receptor kinase B, and Fyn in the hippocampus of aged mice. The treatment also upregulated the mRNA and protein expression of synaptophysin and growth-associated protein 43 in the hippocampus of these mice. In conclusion, brain-derived neurotrophic factor signaling may play an important role in sustaining and regulating structural synaptic plasticity induced by transcranial magnetic stimulation in the hippocampus of aging mice, and Fyn may be critical during this regulation. These responses may change the structural plasticity of the aging hippocampus, thereby improving cognitive function.

  7. Whole-genome analysis of 5-hydroxymethylcytosine and 5-methylcytosine at base resolution in the human brain

    OpenAIRE

    Wen, Lu; Li, Xianlong; Yan, Liying; Tan, Yuexi; Li, Rong; Zhao, Yangyu; Wang, Yan; Xie, Jingcheng; Zhang, Yan; Song, Chunxiao; Yu, Miao; Liu, Xiaomeng; Zhu, Ping; Li, XiaoYu; Hou, Yu

    2014-01-01

    Background 5-methylcytosine (mC) can be oxidized by the tet methylcytosine dioxygenase (Tet) family of enzymes to 5-hydroxymethylcytosine (hmC), which is an intermediate of mC demethylation and may also be a stable epigenetic modification that influences chromatin structure. hmC is particularly abundant in mammalian brains but its function is currently unknown. A high-resolution hydroxymethylome map is required to fully understand the function of hmC in the human brain. Results We present gen...

  8. In vivo detection of brain Krebs cycle intermediate by hyperpolarized magnetic resonance.

    Science.gov (United States)

    Mishkovsky, Mor; Comment, Arnaud; Gruetter, Rolf

    2012-12-01

    The Krebs (or tricarboxylic acid (TCA)) cycle has a central role in the regulation of brain energy regulation and metabolism, yet brain TCA cycle intermediates have never been directly detected in vivo. This study reports the first direct in vivo observation of a TCA cycle intermediate in intact brain, namely, 2-oxoglutarate, a key biomolecule connecting metabolism to neuronal activity. Our observation reveals important information about in vivo biochemical processes hitherto considered undetectable. In particular, it provides direct evidence that transport across the inner mitochondria membrane is rate limiting in the brain. The hyperpolarized magnetic resonance protocol designed for this study opens the way to direct and real-time studies of TCA cycle kinetics.

  9. Magnetic particle spectroscopy allows precise quantification of nanoparticles after passage through human brain microvascular endothelial cells

    Science.gov (United States)

    Gräfe, C.; Slabu, I.; Wiekhorst, F.; Bergemann, C.; von Eggeling, F.; Hochhaus, A.; Trahms, L.; Clement, J. H.

    2016-06-01

    Crossing the blood–brain barrier is an urgent requirement for the treatment of brain disorders. Superparamagnetic iron oxide nanoparticles (SPIONs) are a promising tool as carriers for therapeutics because of their physical properties, biocompatibility, and their biodegradability. In order to investigate the interaction of nanoparticles with endothelial cell layers in detail, in vitro systems are of great importance. Human brain microvascular endothelial cells are a well-suited blood–brain barrier model. Apart from generating optimal conditions for the barrier-forming cell units, the accurate detection and quantification of SPIONs is a major challenge. For that purpose we use magnetic particle spectroscopy to sensitively and directly quantify the SPION-specific iron content. We could show that SPION concentration depends on incubation time, nanoparticle concentration and location. This model system allows for further investigations on particle uptake and transport at cellular barriers with regard to parameters including particles’ shape, material, size, and coating.

  10. Regional magnetic resonance spectroscopy of the brain in autistic individuals

    Energy Technology Data Exchange (ETDEWEB)

    Hisaoka, S.; Harada, M.; Nishitani, H. [Dept. of Radiology, School of Medicine, University of Tokushima (Japan); Mori, K. [Dept. of Paediatrics, School of Medicine, University of Tokushima (Japan)

    2001-06-01

    We studied the variations in the concentration of metabolites with brain region and age in autistic individuals and normal controls using multiple analysis of covariance. We examined 55 autistic individuals (2-21 years old, 47 male and eight female) and 51 normal children (3 months-15 years old, 26 boys and 25 girls). Single volumes of interest were placed in the frontal, parietal and temporal region on both sides, the brain stem and cingulate gyrus. The concentration of each metabolite was quantified by the water reference method. The concentration of N-acetylaspartate in the temporal regions (Brodmann's areas 41 and 42) in the autistic individuals were significantly lower than those in the controls (P < 0.05), but concentrations in other regions were not significantly different between the autistic individuals and controls. This suggests low density or dysfunction of neurones in Brodmann's areas 41 and 42 in autistic individual, which might be related to the disturbances of the sensory speech centre (Wernicke's area) in autism. (orig.)

  11. Regional magnetic resonance spectroscopy of the brain in autistic individuals

    International Nuclear Information System (INIS)

    We studied the variations in the concentration of metabolites with brain region and age in autistic individuals and normal controls using multiple analysis of covariance. We examined 55 autistic individuals (2-21 years old, 47 male and eight female) and 51 normal children (3 months-15 years old, 26 boys and 25 girls). Single volumes of interest were placed in the frontal, parietal and temporal region on both sides, the brain stem and cingulate gyrus. The concentration of each metabolite was quantified by the water reference method. The concentration of N-acetylaspartate in the temporal regions (Brodmann's areas 41 and 42) in the autistic individuals were significantly lower than those in the controls (P < 0.05), but concentrations in other regions were not significantly different between the autistic individuals and controls. This suggests low density or dysfunction of neurones in Brodmann's areas 41 and 42 in autistic individual, which might be related to the disturbances of the sensory speech centre (Wernicke's area) in autism. (orig.)

  12. High spatial resolution Hall sensor array for edge plasma magnetic field measurements

    Science.gov (United States)

    Liu, Yuhong; Maurer, David A.; Navratil, Gerald A.; Rivera, Nicholas

    2005-09-01

    A one-dimensional, high-spatial resolution, 20-element Hall sensor array has been developed to directly measure the edge plasma perpendicular magnetic field and its fluctuations as a function of radius with 4-mm resolution. The array employs new small-area, high-sensitivity indium antimonide (InSb) Hall probes in combination with a high-density seven-layer printed circuit board to provide for connections to supply Hall current, record the measured Hall voltage output signals, and mitigate inductive pickup. A combination of bench and in situ measurements is described that provides absolute calibration of the diagnostic array in the presence of a strong transverse magnetic field component that is approximately 1000 times greater than the perpendicular fluctuating field needed to be resolved by the diagnostic. The Hall probes calibrated using this method are capable of magnetic field measurements with a sensitivity of 7V/T over the frequency band from 0 to 20 kHz.

  13. Fourier magnetic imaging with nanoscale resolution and compressed sensing speed-up using electronic spins in diamond

    Science.gov (United States)

    Arai, K.; Belthangady, C.; Zhang, H.; Bar-Gill, N.; Devience, S. J.; Cappellaro, P.; Yacoby, A.; Walsworth, R. L.

    2015-10-01

    Optically detected magnetic resonance using nitrogen-vacancy (NV) colour centres in diamond is a leading modality for nanoscale magnetic field imaging, as it provides single electron spin sensitivity, three-dimensional resolution better than 1 nm (ref. 5) and applicability to a wide range of physical and biological samples under ambient conditions. To date, however, NV-diamond magnetic imaging has been performed using ‘real-space’ techniques, which are either limited by optical diffraction to ˜250 nm resolution or require slow, point-by-point scanning for nanoscale resolution, for example, using an atomic force microscope, magnetic tip, or super-resolution optical imaging. Here, we introduce an alternative technique of Fourier magnetic imaging using NV-diamond. In analogy with conventional magnetic resonance imaging (MRI), we employ pulsed magnetic field gradients to phase-encode spatial information on NV electronic spins in wavenumber or ‘k-space’ followed by a fast Fourier transform to yield real-space images with nanoscale resolution, wide field of view and compressed sensing speed-up.

  14. Magnetic nanoformulation of azidothymidine 5’-triphosphate for targeted delivery across the blood–brain barrier

    Directory of Open Access Journals (Sweden)

    Zainulabedin M Saiyed

    2010-03-01

    Full Text Available Zainulabedin M Saiyed, Nimisha H Gandhi, Madhavan PN Nair1Department of Immunology, College of Medicine, Florida International University, Miami, FL, USAAbstract: Despite significant advances in highly active antiretroviral therapy (HAART, the prevalence of neuroAIDS remains high. This is mainly attributed to inability of antiretroviral therapy (ART to cross the blood–brain barrier (BBB, thus resulting in insufficient drug concentration within the brain. Therefore, development of an active drug targeting system is an attractive strategy to increase the efficacy and delivery of ART to the brain. We report herein development of magnetic azidothymidine 5’-triphosphate (AZTTP liposomal nanoformulation and its ability to transmigrate across an in vitro BBB model by application of an external magnetic field. We hypothesize that this magnetically guided nanoformulation can transverse the BBB by direct transport or via monocyte-mediated transport. Magnetic AZTTP liposomes were prepared using a mixture of phosphatidyl choline and cholesterol. The average size of prepared liposomes was about 150 nm with maximum drug and magnetite loading efficiency of 54.5% and 45.3%, respectively. Further, magnetic AZTTP liposomes were checked for transmigration across an in vitro BBB model using direct or monocyte-mediated transport by application of an external magnetic field. The results show that apparent permeability of magnetic AZTTP liposomes was 3-fold higher than free AZTTP. Also, the magnetic AZTTP liposomes were efficiently taken up by monocytes and these magnetic monocytes showed enhanced transendothelial migration compared to normal/non-magnetic monocytes in presence of an external magnetic field. Thus, we anticipate that the developed magnetic nanoformulation can be used for targeting active nucleotide analog reverse transcriptase inhibitors to the brain by application of an external magnetic force and thereby eliminate the brain HIV reservoir and help

  15. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  16. Radiation-Induced Alterations in Mouse Brain Development Characterized by Magnetic Resonance Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gazdzinski, Lisa M.; Cormier, Kyle [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Lu, Fred G. [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Lerch, Jason P. [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Wong, C. Shun [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Nieman, Brian J., E-mail: bjnieman@phenogenomics.ca [Mouse Imaging Centre, Hospital for Sick Children, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada)

    2012-12-01

    Purpose: The purpose of this study was to identify regions of altered development in the mouse brain after cranial irradiation using longitudinal magnetic resonance imaging (MRI). Methods and Materials: Female C57Bl/6 mice received a whole-brain radiation dose of 7 Gy at an infant-equivalent age of 2.5 weeks. MRI was performed before irradiation and at 3 time points following irradiation. Deformation-based morphometry was used to quantify volume and growth rate changes following irradiation. Results: Widespread developmental deficits were observed in both white and gray matter regions following irradiation. Most of the affected brain regions suffered an initial volume deficit followed by growth at a normal rate, remaining smaller in irradiated brains compared with controls at all time points examined. The one exception was the olfactory bulb, which in addition to an early volume deficit, grew at a slower rate thereafter, resulting in a progressive volume deficit relative to controls. Immunohistochemical assessment revealed demyelination in white matter and loss of neural progenitor cells in the subgranular zone of the dentate gyrus and subventricular zone. Conclusions: MRI can detect regional differences in neuroanatomy and brain growth after whole-brain irradiation in the developing mouse. Developmental deficits in neuroanatomy persist, or even progress, and may serve as useful markers of late effects in mouse models. The high-throughput evaluation of brain development enabled by these methods may allow testing of strategies to mitigate late effects after pediatric cranial irradiation.

  17. Internal brain motion pumping of CSF using high-resolution velocity MR imaging

    International Nuclear Information System (INIS)

    An MR velocity density (MRVD) technique able to detect velocities as low as 0.4 mm/sec was applied to obtain images of the brain synchronized to the cardiac cycle in 25 healthy subjects and five patients. During systole (100-200 msec after the R wave), MRVD images demonstrated a caudad velocity in the central regions of the brain, most prominent in the brain stem (up to 1.5 mm/sec). This caudad brain motion and the synchronous ejection of cerebrospinal fluid (CSF) from the ventricles into the basal cisterns, taken together, strongly suggest a cardiac-driven pumping action of the brain on the CSF

  18. Magnetic resonance imaging in assessment of treatment response of gamma knife for brain tumors

    Institute of Scientific and Technical Information of China (English)

    GAO Xiao; ZHANG Xue-ning; ZHANG Yun-ting; YU Chun-shui; XU De-sheng

    2011-01-01

    Objective To review the applications of magnetic resonance imaging (MRI) techniques in assessing treatment response to gamma knife radiosurgery for brain tumors.Data sources Published articles about assessing treatment response to gamma knife radiosurgery for brain tumors were selected using PubMed. The search terms were "MRI", "gamma knife" and "brain tumors".Study selection Articles regarding the MRI techniques using for early assessment of treatment response of gamma knife were selected.Results MRI techniques, especially diffusion weighted imaging, perfusion weighted imaging, magnetic resonance spectroscopy, are useful for early assessment of treatment response of gamma knife by detecting the hemodynamic, metabolic, and cellular alterations. Moreover, they can also provide important information on prognosis.Conclusions Diffusion weighted imaging, perfusion weighted imaging and magnetic resonance spectroscopy can provide early assessment of treatment response of gamma knife for brain tumors, and also information of tumor progression or recurrence earlier than conventional MRI. But there are still many questions to be answered which should be based on the development and advancement of MRI and related disciplines.

  19. Multimodal magnetic resonance imaging evaluation of primary brain tumors.

    Science.gov (United States)

    Treister, Daniel; Kingston, Sara; Hoque, Kristina E; Law, Meng; Shiroishi, Mark S

    2014-08-01

    Gliomas comprise 80% of primary brain neoplasms, with glioblastoma multiforme being the most commonly diagnosed glioma. The annual incidence is 5.26 per 100,000, or 17,000 newly diagnosed cases per year in the United States. The incidence increases with age, peaking between the 6th and 8th decades. Gliomas are more common among Caucasians and occur more often in men. They can be associated with certain rare hereditary syndromes including Cowden, Turcot, Li-Fraumeni, neurofibromatosis type 1 and type 2, tuberous sclerosis, and familial schwannomatosis. Known risk factors include a history of ionizing radiation, family history of glioma, and certain genetic susceptibility variants that are weakly associated with glioma. Preventative measures have not been shown to decrease the risk of later development. In addition, screening tests are unwarranted since early diagnosis and treatment have not been shown to improve outcome. PMID:25173141

  20. Transcranial magnetic stimulation for investigating causal brain-behavioral relationships and their time course.

    Science.gov (United States)

    Sliwinska, Magdalena W; Vitello, Sylvia; Devlin, Joseph T

    2014-01-01

    Transcranial magnetic stimulation (TMS) is a safe, non-invasive brain stimulation technique that uses a strong electromagnet in order to temporarily disrupt information processing in a brain region, generating a short-lived "virtual lesion." Stimulation that interferes with task performance indicates that the affected brain region is necessary to perform the task normally. In other words, unlike neuroimaging methods such as functional magnetic resonance imaging (fMRI) that indicate correlations between brain and behavior, TMS can be used to demonstrate causal brain-behavior relations. Furthermore, by varying the duration and onset of the virtual lesion, TMS can also reveal the time course of normal processing. As a result, TMS has become an important tool in cognitive neuroscience. Advantages of the technique over lesion-deficit studies include better spatial-temporal precision of the disruption effect, the ability to use participants as their own control subjects, and the accessibility of participants. Limitations include concurrent auditory and somatosensory stimulation that may influence task performance, limited access to structures more than a few centimeters from the surface of the scalp, and the relatively large space of free parameters that need to be optimized in order for the experiment to work. Experimental designs that give careful consideration to appropriate control conditions help to address these concerns. This article illustrates these issues with TMS results that investigate the spatial and temporal contributions of the left supramarginal gyrus (SMG) to reading. PMID:25079670

  1. Brain

    Science.gov (United States)

    ... will return after updating. Resources Archived Modules Updates Brain Cerebrum The cerebrum is the part of the ... the outside of the brain and spinal cord. Brain Stem The brain stem is the part of ...

  2. Magnetic Resonance Imaging and Computed Tomography of the Brain-50 Years of Innovation, With a Focus on the Future.

    Science.gov (United States)

    Runge, Val M; Aoki, Shigeki; Bradley, William G; Chang, Kee-Hyun; Essig, Marco; Ma, Lin; Ross, Jeffrey S; Valavanis, Anton

    2015-09-01

    This review focuses specifically on the developments in brain imaging, as opposed to the spine, and specifically conventional, clinical, cross-sectional imaging, looking primarily at advances in magnetic resonance imaging (MRI) and computed tomography (CT). These fields are viewed from a perspective of landmark publications in the last 50 years and subsequently more in depth using sentinel publications from the last 5 years. It is also written from a personal perspective, with the authors having witnessed the evolution of both fields from their initial clinical introduction to their current state. Both CT and MRI have made tremendous advances during this time, regarding not only sensitivity and spatial resolution, but also in terms of the speed of image acquisition. Advances in CT in recent years have focused in part on reduced radiation dose, an important topic for the years to come. Magnetic resonance imaging has seen the development of a plethora of scan techniques, with marked superiority to CT in terms of tissue contrast due to the many parameters that can be assessed, and their intrinsic sensitivity. Future advances in MRI for clinical practice will likely focus both on new acquisition techniques that offer advances in speed and resolution, for example, simultaneous multislice imaging and data sparsity, and on standardization and further automation of image acquisition and analysis. Functional imaging techniques including specifically perfusion and functional magnetic resonance imaging will be further integrated into the workflow to provide pathophysiologic information that influence differential diagnosis, assist treatment decision and planning, and identify and follow treatment-related changes.

  3. Manganese-enhanced magnetic resonance imaging (MEMRI) of brain activity and applications to early detection of brain ischemia.

    Science.gov (United States)

    Aoki, Ichio; Naruse, Shoji; Tanaka, Chuzo

    2004-12-01

    Divalent manganese ion (Mn2+) has been reported to be a useful contrast agent for functional MRI, through a technique named activity-induced manganese-dependent MRI (AIM). In AIM, signal enhancement is related to functional increases in calcium influx, and therefore AIM is, thus far, the only MRI method able to map brain activation in vivo independently of the surrogate hemodynamic changes used in functional MRI. Because of its high signal-to-noise ratio (SNR) and high sensitivity, AIM allows the use of multi-slice or three-dimensional MRI techniques to map functional activity at high spatial resolution. In the present review, we define AIM as a functional MRI tool based on the administration of divalent ionized manganese through an open or disrupted blood-brain barrier (BBB). The adequacy and efficacy of AIM in detecting neural activation is described in light of supporting experiments on inhibition of calcium channels, FOS expression, and on direct comparison to BOLD- and perfusion-based functional MRI. Two main applications of AIM, mapping brain activation in rat somatosensory cortex, as well stroke research based on the well-established middle cerebral artery occlusion model, are described in detail. Methodological problems associated with a strong dependence on anesthetic conditions, potential corruption due to disruption of the BBB, and unspecific increase of the baseline signal due to acoustical noise are discussed. Finally, recommended preparation methods and experimental protocols for AIM are introduced.

  4. Evaluation of Cancer Metabolomics Using ex vivo High Resolution Magic Angle Spinning (HRMAS) Magnetic Resonance Spectroscopy (MRS).

    Science.gov (United States)

    Fuss, Taylor L; Cheng, Leo L

    2016-03-22

    According to World Health Organization (WHO) estimates, cancer is responsible for more deaths than all coronary heart disease or stroke worldwide, serving as a major public health threat around the world. High resolution magic angle spinning (HRMAS) magnetic resonance spectroscopy (MRS) has demonstrated its usefulness in the identification of cancer metabolic markers with the potential to improve diagnosis and prognosis for the oncology clinic, due partially to its ability to preserve tissue architecture for subsequent histological and molecular pathology analysis. Capable of the quantification of individual metabolites, ratios of metabolites, and entire metabolomic profiles, HRMAS MRS is one of the major techniques now used in cancer metabolomic research. This article reviews and discusses literature reports of HRMAS MRS studies of cancer metabolomics published between 2010 and 2015 according to anatomical origins, including brain, breast, prostate, lung, gastrointestinal, and neuroendocrine cancers. These studies focused on improving diagnosis and understanding patient prognostication, monitoring treatment effects, as well as correlating with the use of in vivo MRS in cancer clinics.

  5. 3D-visualization of intracranial vessels and brain anatomy in magnetic resonance imaging

    International Nuclear Information System (INIS)

    This paper describes a 3D-image processing approach to generate a combination display of intracranial vessels and adjacent brain tissue surfaces in magnetic resonance imaging (MRI). The algorithm is based on the ray-tracing principle and may be regarded as a union of the techniques of surface integration and maximum intensity projection (MIP). Measurement methods and preprocessing steps of acquisition of a flow-compensated vessel dataset and a T1 weighted tissue volume with isolated brain with equal partitioning are described. The method is intended as a tool for the optimization of neurosurgical planning

  6. Effect of Repetitive Transcranial Magnetic Stimulation on Patients with Brain Injury and Dysphagia

    OpenAIRE

    Kim, Leesuk; Chun, Min Ho; Kim, Bo Ryun; Lee, Sook Joung

    2011-01-01

    Objective To investigate the effect of repetitive transcranial magnetic stimulation (rTMS) on recovery of the swallowing function in patients with a brain injury. Method Patients with a brain injury and dysphagia were enrolled. Patients were randomly assigned to sham, and low and high frequency stimulation groups. We performed rTMS at 100% of motor evoked potential (MEP) threshold and a 5 Hz frequency for 10 seconds and then repeated this every minute in the high frequency group. In the low f...

  7. Waxholm Space atlas of the rat brain hippocampal region: three-dimensional delineations based on magnetic resonance and diffusion tensor imaging.

    Science.gov (United States)

    Kjonigsen, Lisa J; Lillehaug, Sveinung; Bjaalie, Jan G; Witter, Menno P; Leergaard, Trygve B

    2015-03-01

    Atlases of the rat brain are widely used as reference for orientation, planning of experiments, and as tools for assigning location to experimental data. Improved quality and use of magnetic resonance imaging (MRI) and other tomographical imaging techniques in rats have allowed the development of new three-dimensional (3-D) volumetric brain atlas templates. The rat hippocampal region is a commonly used model for basic research on memory and learning, and for preclinical investigations of brain disease. The region features a complex anatomical organization with multiple subdivisions that can be identified on the basis of specific cytoarchitectonic or chemoarchitectonic criteria. We here investigate the extent to which it is possible to identify boundaries of divisions of the hippocampal region on the basis of high-resolution MRI contrast. We present the boundaries of 13 divisions, identified and delineated based on multiple types of image contrast observed in the recently published Waxholm Space MRI/DTI template for the Sprague Dawley rat brain (Papp et al., Neuroimage 97:374-386, 2014). The new detailed delineations of the hippocampal formation and parahippocampal region (Waxholm Space atlas of the Sprague Dawley rat brain, v2.0) are shared via the INCF Software Center (http://software.incf.org/), where also the MRI/DTI reference template is available. The present update of the Waxholm Space atlas of the rat brain is intended to facilitate interpretation, analysis, and integration of experimental data from this anatomically complex region.

  8. High-resolution magnetic field imaging with a nitrogen-vacancy diamond sensor integrated with a photonic-crystal fiber.

    Science.gov (United States)

    Fedotov, I V; Blakley, S M; Serebryannikov, E E; Hemmer, P; Scully, M O; Zheltikov, A M

    2016-02-01

    We demonstrate high-resolution magnetic field imaging with a scanning fiber-optic probe which couples nitrogen-vacancy (NV) centers in diamond to a high-numerical-aperture photonic-crystal fiber integrated with a two-wire microwave transmission line. Magnetic resonance excitation of NV centers driven by the microwave field is read out through optical interrogation through the photonic-crystal fiber to enable high-speed, high-sensitivity magnetic field imaging with sub 30 μm spatial resolution. PMID:26907400

  9. ROLE OF MAGNETIC RESONANCE IMAGING BRAIN IN EVALUATION OF SEIZURES

    Directory of Open Access Journals (Sweden)

    Athira

    2015-09-01

    Full Text Available BACKGROUND AND OBJECTIVES: In patients with seizures a dedicated MRI protocol is a useful tool in the detection of an epileptogenic focus, including congenital, neoplastic and degenerative. Resection of these lesions can lead to seizure freedom in most patients. In this context, a prospective study was conducted to evaluate the etiology of seizures using MRI brain. METHODOLOGY: 120 patients presenting with seizures, above the age of 2years, referred to the Department of Radio - diagnosis were included in this study. RESULTS: In this study, the MR examination revealed pathological findi ngs i n 32.50% (39 out of 120 patients which includes: mesial temporal sclerosis - 14.2% (17, cerebral infarct with gliosis - 6.6% (8, meningioma - 2.5% (3, hypoxic ischemic encephalopathy - 1.6% (2, cortical dysplasia - 1.6% (2, tuberous sclerosis - 11.6% (2, nodula r heterotopias - 0.83% (1, neurocysticercosis - 0.83% (1%, metastasis - 0.83% (1, Dyke Davidoff Maison syndrome - 0.83% (1 and Arnold Chiari Malformation 0.83% (1. CONCLUSION: This study concludes that MR imaging plays a pivotal role in the evaluation of pati ents with seizures using a dedicated MRI seizure protocol to confirm or rule out any organic or developmental lesions. The most common abnormality seen in this study was mesial temporal sclerosis.

  10. Magnetic resonance brain tissue segmentation based on sparse representations

    Science.gov (United States)

    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).

  11. Time-difference imaging of magnetic induction tomography in a three-layer brain physical phantom

    International Nuclear Information System (INIS)

    Magnetic induction tomography (MIT) is a contactless and noninvasive technique to reconstruct the conductivity distribution in a human cross-section. In this paper, we want to study the feasibility of imaging the low-contrast perturbation and small volume object in human brains. We construct a three-layer brain physical phantom which mimics the real conductivity distribution of brains by introducing an artificial skull layer. Using our MIT data acquisition system on this phantom and differential algorithm, we have obtained a series of reconstructed images of conductivity perturbation objects. All of the conductivity perturbation objects in the brain phantom can be clearly distinguished in the reconstructed images. The minimum detectable conductivity difference between the object and the background is 0.03 S m−1 (12.5%). The minimum detectable inner volume of the objects is 3.4 cm3. The three-layer brain physical phantom is able to simulate the conductivity distribution of the main structures of a human brain. The images of the low-contrast perturbation and small volume object show the prospect of MIT in the future. (paper)

  12. Prenatal magnetic resonance imaging: brain normal linear biometric values below 24 gestational weeks

    International Nuclear Information System (INIS)

    Prenatal magnetic resonance (MR) imaging is currently used to measure quantitative data concerning brain structural development. At present, morphometric MR imaging studies have been focused mostly on the third trimester of gestational age. However, in many countries, because of legal restriction on abortion timing, the majority of MR imaging fetal examination has to be carried out during the last part of the second trimester of pregnancy (i.e., before the 24th week of gestation). Accurate and reliable normative data of the brain between 20 and 24 weeks of gestation is not available. This report provides easy and practical parametric support to assess those normative data. From a database of 1,200 fetal MR imaging studies, we retrospectively selected 84 studies of the brain of fetuses aged 20-24 weeks of gestation that resulted normal on clinical and radiological follow-up. Fetuses with proved or suspected infections, twin pregnancy, and fetuses of mothers affected by pathology that might have influenced fetal growth were excluded. Linear biometrical measurements of the main cerebral structures were obtained by three experienced pediatric neuroradiologists. A substantial interobserver agreement for each measurements was reached, and normative data with median, maximum, and minimum value were obtained for brain structures. The knowledge of a range of normality and interindividual variability of linear biometrical values for the developing brain between 20th and 24th weeks of gestation may be valuable in assessing normal brain development in clinical settings. (orig.)

  13. Brain damages in ketamine addicts as revealed by magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Chunmei eWang

    2013-07-01

    Full Text Available Ketamine, a known antagonist of N-methyl-D-aspartic (NMDA glutamate receptors, had been used as an anesthetic particularly for pediatric or for cardiac patients. Unfortunately, ketamine has become an abusive drug in many parts of the world while chronic and prolonged usage led to damages of many organs including the brain. However, no studies on possible damages in the brains induced by chronic ketamine abuse have been documented in the human via neuroimaging. This paper described for the first time via employing magnetic resonance imaging (MRI the changes in ketamine addicts of 0.5 to 12 years and illustrated the possible brain regions susceptible to ketamine abuse. Twenty-one ketamine addicts were recruited and the results showed that the lesions in the brains of ketamine addicts were located in many regions which appeared 2-4 years after ketamine addiction. Cortical atrophy was usually evident in the frontal, parietal or occipital cortices of addicts. Such study confirmed that many brain regions in the human were susceptible to chronic ketamine injury and presented a diffuse effect of ketamine on the brain which might differ from other central nervous system (CNS drugs, such as cocaine, heroin and methamphetamine.

  14. Prenatal magnetic resonance imaging: brain normal linear biometric values below 24 gestational weeks

    Energy Technology Data Exchange (ETDEWEB)

    Parazzini, C.; Righini, A.; Triulzi, F. [Children' s Hospital ' ' V. Buzzi' ' , Department of Radiology and Neuroradiology, Milan (Italy); Rustico, M. [Children' s Hospital ' ' V. Buzzi' ' , Department of Obstetrics and Gynecology, Milan (Italy); Consonni, D. [Fondazione IRCCS Ospedale Maggiore Policlinico, Unit of Epidemiology, Milan (Italy)

    2008-10-15

    Prenatal magnetic resonance (MR) imaging is currently used to measure quantitative data concerning brain structural development. At present, morphometric MR imaging studies have been focused mostly on the third trimester of gestational age. However, in many countries, because of legal restriction on abortion timing, the majority of MR imaging fetal examination has to be carried out during the last part of the second trimester of pregnancy (i.e., before the 24th week of gestation). Accurate and reliable normative data of the brain between 20 and 24 weeks of gestation is not available. This report provides easy and practical parametric support to assess those normative data. From a database of 1,200 fetal MR imaging studies, we retrospectively selected 84 studies of the brain of fetuses aged 20-24 weeks of gestation that resulted normal on clinical and radiological follow-up. Fetuses with proved or suspected infections, twin pregnancy, and fetuses of mothers affected by pathology that might have influenced fetal growth were excluded. Linear biometrical measurements of the main cerebral structures were obtained by three experienced pediatric neuroradiologists. A substantial interobserver agreement for each measurements was reached, and normative data with median, maximum, and minimum value were obtained for brain structures. The knowledge of a range of normality and interindividual variability of linear biometrical values for the developing brain between 20th and 24th weeks of gestation may be valuable in assessing normal brain development in clinical settings. (orig.)

  15. Segmentation of tongue muscles from super-resolution magnetic resonance images.

    Science.gov (United States)

    Ibragimov, Bulat; Prince, Jerry L; Murano, Emi Z; Woo, Jonghye; Stone, Maureen; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2015-02-01

    Imaging and quantification of tongue anatomy is helpful in surgical planning, post-operative rehabilitation of tongue cancer patients, and studying of how humans adapt and learn new strategies for breathing, swallowing and speaking to compensate for changes in function caused by disease, medical interventions or aging. In vivo acquisition of high-resolution three-dimensional (3D) magnetic resonance (MR) images with clearly visible tongue muscles is currently not feasible because of breathing and involuntary swallowing motions that occur over lengthy imaging times. However, recent advances in image reconstruction now allow the generation of super-resolution 3D MR images from sets of orthogonal images, acquired at a high in-plane resolution and combined using super-resolution techniques. This paper presents, to the best of our knowledge, the first attempt towards automatic tongue muscle segmentation from MR images. We devised a database of ten super-resolution 3D MR images, in which the genioglossus and inferior longitudinalis tongue muscles were manually segmented and annotated with landmarks. We demonstrate the feasibility of segmenting the muscles of interest automatically by applying the landmark-based game-theoretic framework (GTF), where a landmark detector based on Haar-like features and an optimal assignment-based shape representation were integrated. The obtained segmentation results were validated against an independent manual segmentation performed by a second observer, as well as against B-splines and demons atlasing approaches. The segmentation performance resulted in mean Dice coefficients of 85.3%, 81.8%, 78.8% and 75.8% for the second observer, GTF, B-splines atlasing and demons atlasing, respectively. The obtained level of segmentation accuracy indicates that computerized tongue muscle segmentation may be used in surgical planning and treatment outcome analysis of tongue cancer patients, and in studies of normal subjects and subjects with speech and

  16. High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

    Institute of Scientific and Technical Information of China (English)

    Xian-Jin Zhu; Wu Wang; Zun-Jing Liu

    2016-01-01

    Objective:To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.Date Sources:We retrieved information from PubMed database up to December 2015,using various search terms including vessel wall imaging (VWI),high-resolution magnetic resonance imaging,intracranial arterial stenosis,black blood,and intracranial atherosclerosis.Study Selection:We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI.We organized this data to explain the value of VWI in clinical application.Results:VWI with black blood technique could provide high-quality images with submillimeter voxel size,and display both the vessel wall and lumen of intracranial artery simultaneously.Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening,enhancement,and vessel remodeling on VWI.This technique could be used for determining causes of stenosis,identification of stroke mechanism,risk-stratifying patients,and directing therapeutic management in clinical practice.In addition,a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.Conclusions:This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

  17. Semi-automated structural analysis of high resolution magnetic and gamma-ray spectrometry airborne surveys

    Science.gov (United States)

    Debeglia, N.; Martelet, G.; Perrin, J.; Truffert, C.; Ledru, P.; Tourlière, B.

    2005-08-01

    A user-controlled procedure was implemented for the structural analysis of geophysical maps. Local edge segments are first extracted using a suitable edge detector function, then linked into straight discontinuities and, finally, organised in complex boundary lines best delineating geophysical features. Final boundary lines may be attributed by a geologist to lithological contacts and/or structural geological features. Tests of some edge detectors, (i) horizontal gradient magnitude (HGM), (ii) various orders of the analytic signal ( An), reduced to the pole or not, (iii) enhanced horizontal derivative (EHD), (iv) composite analytic signal (CAS), were performed on synthetic magnetic data (with and without noise). As a result of these comparisons, the horizontal gradient appears to remain the best operator for the analysis of magnetic data. Computation of gradients in the frequency domain, including filtering and upward continuation of noisy data, is well-suited to the extraction of magnetic gradients associated to deep sources, while space-domain smoothing and differentiation techniques is generally preferable in the case of shallow magnetic sources, or for gamma-ray spectrometry analysis. Algorithms for edge extraction, segment linking, and line following can be controlled by choosing adequate edge detector and processing parameters which allows adaptation to a desired scale of interpretation. Tests on synthetic and real case data demonstrate the adaptability of the procedure and its ability to produce basic layer for multi-data analysis. The method was applied to the interpretation of high-resolution airborne magnetic and gamma-ray spectrometry data collected in northern Namibia. It allowed the delineation of dyke networks concealed by superficial weathering and demonstrated the presence of lithological variations in alluvial flows. The output from the structural analysis procedure are compatible with standard GIS softwares and enable the geologist to (i) compare

  18. Magnetic resonance electrical impedance tomography (MREIT) for high-resolution conductivity imaging

    International Nuclear Information System (INIS)

    Cross-sectional imaging of an electrical conductivity distribution inside the human body has been an active research goal in impedance imaging. By injecting current into an electrically conducting object through surface electrodes, we induce current density and voltage distributions. Based on the fact that these are determined by the conductivity distribution as well as the geometry of the object and the adopted electrode configuration, electrical impedance tomography (EIT) reconstructs cross-sectional conductivity images using measured current–voltage data on the surface. Unfortunately, there exist inherent technical difficulties in EIT. First, the relationship between the boundary current–voltage data and the internal conductivity distribution bears a nonlinearity and low sensitivity, and hence the inverse problem of recovering the conductivity distribution is ill posed. Second, it is difficult to obtain accurate information on the boundary geometry and electrode positions in practice, and the inverse problem is sensitive to these modeling errors as well as measurement artifacts and noise. These result in EIT images with a poor spatial resolution. In order to produce high-resolution conductivity images, magnetic resonance electrical impedance tomography (MREIT) has been lately developed. Noting that injection current produces a magnetic as well as electric field inside the imaging object, we can measure the induced internal magnetic flux density data using an MRI scanner. Utilization of the internal magnetic flux density is the key idea of MREIT to overcome the technical difficulties in EIT. Following original ideas on MREIT in early 1990s, there has been a rapid progress in its theory, algorithm and experimental techniques. The technique has now advanced to the stage of human experiments. Though it is still a few steps away from routine clinical use, its potential is high as a new impedance imaging modality providing conductivity images with a spatial

  19. High-Resolution Magnetic Analysis of the Nussloch Loess-Palaeosol Sequence

    Science.gov (United States)

    Taylor, S. N.; Lagroix, F.

    2012-12-01

    By performing a detailed rock magnetic analysis of loess-palaeosol sequences, it is possible to identify pedogenic, diagenetic and depositional processes while constraining climate variations (both local and regional). The Nussloch loess-palaeosol sequences are located on the Odenwald plateau near the right bank of the Rhine Valley in Germany (49°18'59''N; 8°43'54''E). This study uses a 13m section of the P4 sequence which has an age range of approximately 18kyrs to 33kyrs; with a tephra layer (Eltviller Tuff) marked at ~21kyrs. Using a 2cm sub-sampling resolution, the subsequent rock magnetic study of the P4 sequence includes on all samples hysteresis properties, their derived parameters, IRMs and ARMs and low-temperature magnetic properties on representative samples. The sequence divides magnetically into a series of 7 minor zones, identified from the hysteresis parameters, underlying 3 major zones from which also the stratigraphy shows: 1. fine-grained homogeneous loess from 0-8m, 2. coarser-grained homogeneous loess from 8-11m, 3. prominent interbedded gleys from 11-13m. High-coercivity grains dominate a fairly constant mineralogy in Zone 1 whereas in Zone 2 there is a transition into softer magnetic minerals. Zone 3 has a wide range of magnetic properties, a consequence of rapid changes in the stratigraphy. The bulk magnetic signal is fairly weak (χferri ranges from 5.19×10-8 to 1.55×10-7 m3kg-1 with the higher mean in Zone 2) and has a significant contribution of hard magnetic minerals with an absence of SP particles. Even though the signal from iron-bearing minerals dominates, the paramagnetic signal increases with depth, especially below 11m. In terms of the deposited material, the marked gleys generally show lower values of χ, MRS, MS and S-ratios and higher values of coercivity with respect to the unaltered loess. Not only is there a greater abundance of magnetic minerals in the loess but also the minerals are magnetically softer compared to those

  20. Effect of slice thickness on brain magnetic resonance image texture analysis

    OpenAIRE

    Heinonen Tomi; Luukkaala Tiina; Harrison Lara CV; Savio Sami J; Dastidar Prasun; Soimakallio Seppo; Eskola Hannu J

    2010-01-01

    Abstract Background The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients. Methods We averaged the intensities of three consecutive 1-mm slices to simulate 3-mm slices. Two h...

  1. Effects of extremely low frequency magnetic field on oxidative balance in brain of rats.

    Science.gov (United States)

    Ciejka, Elzbieta; Kleniewska, P; Skibska, B; Goraca, A

    2011-12-01

    Extremely low frequency magnetic field (ELF-MF) may result in oxidative DNA damage and lipid peroxidation with an ultimate effect on a number of systemic disturbances and cell death. The aim of the study is to assess the effect of ELF-MF parameters most frequently used in magnetotherapy on reactive oxygen species generation (ROS) in brain tissue of experimental animals depending on the time of exposure to this field. The research material included adult male Sprague-Dawley rats, aged 3-4 months. The animals were divided into 3 groups: I - control (shame) group; II - exposed to the following parameters of the magnetic field: 7 mT, 40 Hz, 30 min/day, 10 days; III - exposed to the ELF-MF parameters of 7 mT, 40 Hz, 60 min/day, 10 days. The selected parameters of oxidative stress: thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H(2)O(2)), total free sulphydryl groups (-SH groups) and protein in brain homogenates were measured after the exposure of rats to the magnetic field. ELF-MF parameters of 7 mT, 40 Hz, 30 min/day for 10 days caused a significant increase in lipid peroxidation and insignificant increase in H(2)O(2) and free -SH groups. The same ELF-MF parameters but applied for 60 min/day caused a significant increase in free -SH groups and protein concentration in the brain homogenates indicating the adaptive mechanism. The study has shown that ELF-MF applied for 30 min/day for 10 days can affect free radical generation in the brain. Prolongation of the exposure to ELF-MF (60/min/day) caused adaptation to this field. The effect of ELF-MF irradiation on oxidative stress parameters depends on the time of animal exposure to magnetic field. PMID:22314568

  2. Correlation between voxel based morphometry and manual volumetry in magnetic resonance images of the human brain

    OpenAIRE

    Ricardo R. Uchida; Cristina M. Del-Ben; David Araújo; Geraldo Busatto-Filho; Duran, Fábio L.S.; Crippa, José A. S.; Graeff, Frederico G.

    2008-01-01

    This is a comparative study between manual volumetry (MV) and voxel based morphometry (VBM) as methods of evaluating the volume of brain structures in magnetic resonance images. The volumes of the hippocampus and the amygdala of 16 panic disorder patients and 16 healthy controls measured through MV were correlated with the volumes of gray matter estimated by optimized modulated VBM. The chosen structures are composed almost exclusively of gray matter. Using a 4 mm Gaussian filter, statistical...

  3. Magnetic resonance imaging spectrum of perinatal hypoxic-ischemic brain injury

    Directory of Open Access Journals (Sweden)

    Binoj Varghese

    2016-01-01

    Full Text Available Perinatal hypoxic–ischemic brain injury results in neonatal hypoxic–ischemic encephalopathy and serious long-term neurodevelopmental sequelae. Magnetic resonance imaging (MRI of the brain is an ideal and safe imaging modality for suspected hypoxic–ischemic injury. The pattern of injury depends on brain maturity at the time of insult, severity of hypotension, and duration of insult. Time of imaging after the insult influences the imaging findings. Mild to moderate hypoperfusion results in germinal matrix hemorrhages and periventricular leukomalacia in preterm neonates and parasagittal watershed territory infarcts in full-term neonates. Severe insult preferentially damages the deep gray matter in both term and preterm infants. However, associated frequent perirolandic injury is seen in term neonates. MRI is useful in establishing the clinical diagnosis, assessing the severity of injury, and thereby prognosticating the outcome. Familiarity with imaging spectrum and insight into factors affecting the injury will enlighten the radiologist to provide an appropriate diagnosis.

  4. Positron Emission Tomography and Magnetic Resonance Imaging of the Brain in Fabry Disease

    DEFF Research Database (Denmark)

    Korsholm, Kirsten; Feldt-Rasmussen, Ulla; Granqvist, Henrik;

    2015-01-01

    risk of cerebrovascular disease at a young age in addition to heart and kidney failure. OBJECTIVE: The objective of this study was to assess brain function and structure in the Danish cohort of patients with Fabry disease in a prospective way using 18-fluoro-deoxyglucose (F-18 FDG) positron emission...... tomography (PET) and magnetic resonance imaging (MRI). PATIENTS: Forty patients with Fabry disease (14 males, 26 females, age at inclusion: 10-66 years, median: 39 years) underwent a brain F-18-FDG-PET-scan at inclusion, and 31 patients were followed with FDG-PET biannually for up to seven years. All...... patients (except one) had a brain MRI-scan at inclusion, and 34 patients were followed with MRI biannually for up to nine years. IMAGE ANALYSIS: The FDG-PET-images were inspected visually and analysed using a quantitative 3-dimensional stereotactic surface projection analysis (Neurostat). MRI images were...

  5. Detection of Brain Tumor and Extraction of Texture Features using Magnetic Resonance Images

    Directory of Open Access Journals (Sweden)

    Prof. Dilip Kumar Gandhi

    2012-10-01

    Full Text Available Brain Cancer Detection system is designed. Aim of this paper is to locate the tumor and determine the texture features from a Brain Cancer affected MRI. A computer based diagnosis is performed in order to detect the tumors from given Magnetic Resonance Image. Basic image processing techniques are used to locate the tumor region. Basic techniques consist of image enhancement, image bianarization, and image morphological operations. Texture features are computed using the Gray Level Co-occurrence Matrix. Texture features consists of five distinct features. Selective features or the combination of selective features will be used in the future to determine the class of the query image. Astrocytoma type of Brain Cancer affected images are used only for simplicity

  6. Region specific optimization of continuous linear attenuation coefficients based on UTE (RESOLUTE): application to PET/MR brain imaging

    Science.gov (United States)

    Ladefoged, Claes N.; Benoit, Didier; Law, Ian; Holm, Søren; Kjær, Andreas; Højgaard, Liselotte; Hansen, Adam E.; Andersen, Flemming L.

    2015-10-01

    The reconstruction of PET brain data in a PET/MR hybrid scanner is challenging in the absence of transmission sources, where MR images are used for MR-based attenuation correction (MR-AC). The main challenge of MR-AC is to separate bone and air, as neither have a signal in traditional MR images, and to assign the correct linear attenuation coefficient to bone. The ultra-short echo time (UTE) MR sequence was proposed as a basis for MR-AC as this sequence shows a small signal in bone. The purpose of this study was to develop a new clinically feasible MR-AC method with patient specific continuous-valued linear attenuation coefficients in bone that provides accurate reconstructed PET image data. A total of 164 [18F]FDG PET/MR patients were included in this study, of which 10 were used for training. MR-AC was based on either standard CT (reference), UTE or our method (RESOLUTE). The reconstructed PET images were evaluated in the whole brain, as well as regionally in the brain using a ROI-based analysis. Our method segments air, brain, cerebral spinal fluid, and soft tissue voxels on the unprocessed UTE TE images, and uses a mapping of R2* values to CT Hounsfield Units (HU) to measure the density in bone voxels. The average error of our method in the brain was 0.1% and less than 1.2% in any region of the brain. On average 95% of the brain was within  ±10% of PETCT, compared to 72% when using UTE. The proposed method is clinically feasible, reducing both the global and local errors on the reconstructed PET images, as well as limiting the number and extent of the outliers.

  7. Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  8. Brain-targeted delivery of trans-activating transcriptor-conjugated magnetic PLGA/lipid nanoparticles.

    Directory of Open Access Journals (Sweden)

    Xiangru Wen

    Full Text Available Magnetic poly (D,L-lactide-co-glycolide (PLGA/lipid nanoparticles (MPLs were fabricated from PLGA, L-α-phosphatidylethanolamine (DOPE, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-amino (polyethylene glycol (DSPE-PEG-NH2, and magnetic nanoparticles (NPs, and then conjugated to trans-activating transcriptor (TAT peptide. The TAT-MPLs were designed to target the brain by magnetic guidance and TAT conjugation. The drugs hesperidin (HES, naringin (NAR, and glutathione (GSH were encapsulated in MPLs with drug loading capacity (>10% and drug encapsulation efficiency (>90%. The therapeutic efficacy of the drug-loaded TAT-MPLs in bEnd.3 cells was compared with that of drug-loaded MPLs. The cells accumulated higher levels of TAT-MPLs than MPLs. In addition, the accumulation of QD-loaded fluorescein isothiocyanate (FITC-labeled TAT-MPLs in bEnd.3 cells was dose and time dependent. Our results show that TAT-conjugated MPLs may function as an effective drug delivery system that crosses the blood brain barrier to the brain.

  9. Whole brain magnetization transfer histogram analysis of pediatric acute lymphoblastic leukemia patients receiving intrathecal methotrexate therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Akira [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: yakira@kuhp.kyoto-u.ac.jp; Miki, Yukio [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: mikiy@kuhp.kyoto-u.ac.jp; Adachi, Souichi [Department of Pediatrics, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: sadachi@kuhp.kyoto-u.ac.jp (and others)

    2006-03-15

    Background and purpose: The purpose of this prospective study was to evaluate the hypothesis that magnetization transfer ratio (MTR) histogram analysis of the whole brain could detect early and subtle brain changes nonapparent on conventional magnetic resonance imaging (MRI) in children with acute lymphoblastic leukemia (ALL) receiving methotrexate (MTX) therapy. Materials and methods: Subjects in this prospective study comprised 10 children with ALL (mean age, 6 years; range, 0-16 years). In addition to conventional MRI, magnetization transfer images were obtained before and after intrathecal and intravenous MTX therapy. MTR values were calculated and plotted as a histogram, and peak height and location were calculated. Differences in peak height and location between pre- and post-MTX therapy scans were statistically analyzed. Conventional MRI was evaluated for abnormal signal area in white matter. Results: MTR peak height was significantly lower on post-MTX therapy scans than on pre-MTX therapy scans (p = 0.002). No significant differences in peak location were identified between pre- and post-chemotherapy imaging. No abnormal signals were noted in white matter on either pre- or post-MTX therapy conventional MRI. Conclusions: This study demonstrates that MTR histogram analysis allows better detection of early and subtle brain changes in ALL patients who receive MTX therapy than conventional MRI.

  10. Ultra-fast magnetic resonance encephalography of physiological brain activity - Glymphatic pulsation mechanisms?

    Science.gov (United States)

    Kiviniemi, Vesa; Wang, Xindi; Korhonen, Vesa; Keinänen, Tuija; Tuovinen, Timo; Autio, Joonas; LeVan, Pierre; Keilholz, Shella; Zang, Yu-Feng; Hennig, Jürgen; Nedergaard, Maiken

    2016-06-01

    The theory on the glymphatic convection mechanism of cerebrospinal fluid holds that cardiac pulsations in part pump cerebrospinal fluid from the peri-arterial spaces through the extracellular tissue into the peri-venous spaces facilitated by aquaporin water channels. Since cardiac pulses cannot be the sole mechanism of glymphatic propulsion, we searched for additional cerebrospinal fluid pulsations in the human brain with ultra-fast magnetic resonance encephalography. We detected three types of physiological mechanisms affecting cerebral cerebrospinal fluid pulsations: cardiac, respiratory, and very low frequency pulsations. The cardiac pulsations induce a negative magnetic resonance encephalography signal change in peri-arterial regions that extends centrifugally and covers the brain in ≈1 Hz cycles. The respiratory ≈0.3 Hz pulsations are centripetal periodical pulses that occur dominantly in peri-venous areas. The third type of pulsation was very low frequency (VLF 0.001-0.023 Hz) and low frequency (LF 0.023-0.73 Hz) waves that both propagate with unique spatiotemporal patterns. Our findings using critically sampled magnetic resonance encephalography open a new view into cerebral fluid dynamics. Since glymphatic system failure may precede protein accumulations in diseases such as Alzheimer's dementia, this methodological advance offers a novel approach to image brain fluid dynamics that potentially can enable early detection and intervention in neurodegenerative diseases. PMID:26690495

  11. Monitoring gold nanoparticle distribution with high resolution using photo-magnetic imaging

    Science.gov (United States)

    Luk, Alex T.; Nouizi, Farouk; Marks, Michael; Kart, Turkay; Gulsen, Gultekin

    2016-03-01

    One major advantage of using gold nanoparticles is the possibility of tuning their absorption peak by modifying their surface plasma resonance. They are proven to be a promising multi-functional platform that can be used for many imaging and therapeutic applications. As a true multi-modality imaging technique, Photo-Magnetic Imaging (PMI) has a great potential to monitor the distribution of gold nanoparticles non-invasively with MR resolution. With a simple addon of a continuous wave laser to an MRI system, PMI uses the laser induced temperature increase, measured by MR Thermometry (MRT), to provide tissue optical absorption maps at MR resolution. PMI utilizes a Finite Element Method (FEM) based algorithm to solve the combined diffusion and bio-heat equations. This system of combined equations models the photon distribution in the tissue and heat generation due to the absorption of the light and consequent heat diffusion. The key characteristic of PMI is that its spatial resolution is preserved at any depth as long as the temperature change within the imaged medium is detectable by MRT. Agar phantoms containing gold nanoparticles are used to validate the ability of PMI in monitoring their distribution. To make PMI suitable for diagnostic purposes, the laser powers has been kept under the American National Standard Institute maximum skin exposure limits in this study.

  12. Design of High Resolution Soft X-Ray Microcalorimeters Using Magnetic Penetration Thermometers

    Science.gov (United States)

    Busch. Sarah; Balvin, Manuel; Bandler, Simon; Denis, Kevin; Finkbeiner, Fred; Porst, Jan-Patrick; Sadlier, Jack; Smith, Stephen; Stevenson, Thomas

    2012-01-01

    We have designed high-resolution soft x-ray microcalorimeters using magnetic penetration thermometers (MPTs) in an array of pixels covering a total of 2 square centimeters to have a resolving power of 300 at energies around 300 eV. This performance is desirable for studying the soft x-ray background from the warm hot intergalactic medium. MPT devices have small sensor heat capacity and high responsivities, which makes them excellent detector technology for attempting to attain sub-eV resolution. We are investigating the feasibility of pixels with absorbers that are 625 x 625 square micrometers, up to 1 x 1 square millimeters in area and 0.35 micrometer thick and thinner. Our tests have shown that suspended gold absorbers 0.35 micrometers thick (RRR = 6.7) are feasible to fabricate. We modeled the thermal diffusion from such thin gold over the size of a 625 x 625 square micrometer absorber, and conclude that the effect of the thermalization on the resolution of a 300 eV photon is an additional approximately 0.2 eV FWHM of broadening. We discuss the thermal effects of small absorber attachment sterns on solid substrate, as well as considerations for multiplexed readout. We will present the progress we have made towards building and testing this soft x-ray detector.

  13. Current and future applications of magnetic resonance imaging and spectroscopy of the brain in hepatic encephalopathy

    Institute of Scientific and Technical Information of China (English)

    VP Bob Grover; M Alex Dresner; Daniel M Forton; Serena Counsell; David J Larkman; Nayna Patel; Howard C Thomas; Simon D Taylor-Robinson

    2006-01-01

    Hepatic encephalopathy (HE) is a common neuropsychiatric abnormality, which complicates the course of patients with liver disease and results from hepatocellular failure and/or portosystemic shunting.The manifestations of HE are widely variable and involve a spectrum from mild subclinical disturbance to deep coma. Research interest has focused on the role of circulating gut-derived toxins, particularly ammonia, the development of brain swelling and changes in cerebral neurotransmitter systems that lead to global CNS depression and disordered function. Until recently the direct investigation of cerebral function has been difficult in man. However, new magnetic resonance imaging (MRI) techniques provide a non-invasive means of assessment of changes in brain volume (coregistered MRI) and impaired brain function (fMRI), while proton magnetic resonance spectroscopy (1H MRS) detects changes in brain biochemistry, including direct measurement of cerebral osmolytes, such as myoinositol, glutamate and glutamine which govern processes intrinsic to cellular homeostasis, including the accumulation of intracellular water. The concentrations of these intracellular osmolytes alter with hyperammonaemia. MRS-detected metabolite abnormalities correlate with the severity of neuropsychiatric impairment and since MR spectra return towards normal after treatment, the technique may be of use in objective patient monitoring and in assessing the effectiveness of various treatment regimens.

  14. High-resolution X-ray spectroscopy of the magnetic Of?p star HD148937

    CERN Document Server

    Naze, Y; Walborn, N R

    2011-01-01

    High-resolution data of the peculiar magnetic massive star HD148937 were obtained with Chandra-HETGS, and are presented here in combination with a re-analysis of the older XMM-RGS data. The lines of the high-Z elements (Mg, Si, S) were found to be unshifted and relatively narrow (FWHM of about 800km/s), i.e. narrower than the O line recorded by RGS, which possibly indicates that the hot plasma is multi-thermal and has several origins. These data further indicate a main plasma temperature of about 0.6keV and a formation of the X-ray emission at about one stellar radius above the photosphere. From the spectral fits and the H-to-He line ratios, the presence of very hot plasma is however confirmed, though with a smaller relative strength than for the prototype magnetic oblique rotator $\\theta^1$\\,Ori\\,C. Both stars thus share many similarities, but HD148937 appears less extreme than $\\theta^1$\\,Ori\\,C despite having also a large magnetic confinement parameter.

  15. Peculiarities of permalloy thin film microcore hysteretic magnetization process in high space resolution fluxgate device

    Energy Technology Data Exchange (ETDEWEB)

    Skidanov, V. [Institute for Design Problems in Microelectronics RAS, Sovetskaja st. 3, Moscow 124681 (Russian Federation)], E-mail: skidanov@zelnet.ru

    2008-07-15

    Magnetization processes of the sectioned thin film permalloy core were examined in relation with its geometrical dimensions using magnetooptical Kerr technique and ferrofluid observation. It is shown quantitatively the intermediate case between Stoner-Wohlfarth and zero internal field contradicting models takes place. Ferrofluid investigation had shown the stable quasi-saturated state with closing domain structures at permalloy bar edges. Magnetization reversal occurs by hysteretic manner but the hysteresis loop parameters are reproducible and depend strongly upon core geometry. Hysteresis is characterized by parallelogram form with clear critical field and loop slope depending on bars dimensions and their mutual position in array. Loop shape approaches the rectangular form and critical field increases if bar thickness t, width w and bar density in array are decreased. The critical field value H{sub cr} is defined by demagnetizing field at bar edges while the saturation field H{sub s} depends only on width w at of a bar in array. Variation of the bar form or shift of every second bar in array possesses to increase the core thickness to enhance the stray field without increase of the saturating exciting current. The core described can be used with magnetooptical garnet film or Hall sensor in fluxgate regime for magnetic field measurement with space resolution 10-100 mcm.

  16. Diffusion tensor magnetic resonance imaging of glial brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Ferda, Jiri, E-mail: ferda@fnplzen. [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Kastner, Jan [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Mukensnabl, Petr [Sikl' s Institute of Pathological Anatomy, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Choc, Milan [Department of Neurosurgery, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic); Horemuzova, Jana; Ferdova, Eva; Kreuzberg, Boris [Department of Radiology, Charles University Hospital Plzen, Medical Faculty Plzen, Alej Svobody 80, 304 60 Plzen (Czech Republic)

    2010-06-15

    Aim: To evaluate the author's experience with the use of diffusion tensor magnetic resonance imaging (DTI) on patients with glial tumors. Methods: A retrospective evaluation of a group of 24 patients with glial tumors was performed. There were eight patients with Grade II, eight patients with Grade III and eight patients with Grade IV tumors with a histologically proven diagnosis. All the patients underwent routine imaging including T2 weighted images, multidirectional diffusion weighted imaging (measured in 60 non-collinear directions) and T1 weighted non-enhanced and contrast enhanced images. The imaging sequence and evaluation software were produced by Massachusetts General Hospital Corporation (Boston, MA, USA). Fractional anisotropy (FA) maps were calculated in all patients. The white matter FA changes were assessed within the tumorous tissue, on the tumorous borderline and in the normally appearing white matter adjacent to the tumor. A three-dimensional model of the white matter tract was created to demonstrate the space relationship of the tumor and the capsula interna or corpus callosum in each case using the following fiber tracing parameters: FA step 0.25 and a tensor declination angle of 45 gr. An additional assessment of the tumorous tissue enhancement was performed. Results: A uniform homogenous structure with sharp demargination of the Grade II tumors and the wide rim of the intermedial FA in all Grade III tumors respectively, were found during the evaluation of the FA maps. In Grade IV tumors a variable demargination was noted on the FA maps. The sensitivity and specificity for the discrimination of low- and high-grade glial tumors using FA maps was revealed to be 81% and 87% respectively. If the evaluation of the contrast enhancement was combined with the evaluation of the FA maps, both sensitivity and specificity were 100%. Conclusion: Although the evaluation of the fractional anisotropy maps is not sufficient for glioma grading, the

  17. Proton Magnetic Resonance Spectroscopy and MRI Reveal No Evidence for Brain Mitochondrial Dysfunction in Children with Autism Spectrum Disorder

    Science.gov (United States)

    Corrigan, Neva M.; Shaw, Dennis. W. W.; Richards, Todd L.; Estes, Annette M.; Friedman, Seth D.; Petropoulos, Helen; Artru, Alan A.; Dager, Stephen R.

    2012-01-01

    Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ([superscript 1]HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally…

  18. In vivo magnetic resonance imaging and 31P spectroscopy of large human brain tumours at 1.5 tesla

    DEFF Research Database (Denmark)

    Thomsen, C; Jensen, K E; Achten, E;

    1988-01-01

    31P MR spectroscopy of human brain tumours is one feature of magnetic resonance imaging. Eight patients with large superficial brain tumours and eight healthy volunteers were examined with 31P spectroscopy using an 8 cm surface coil for volume selection. Seven frequencies were resolved in our spe...

  19. Quantitative x-ray magnetic circular dichroism mapping with high spatial resolution full-field magnetic transmission soft x-ray spectro-microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, MacCallum J. [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States); Agostino, Christopher J. [Physics Department, University of California, Berkeley, California 94720 (United States); National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); N' Diaye, Alpha T. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Chen, Gong [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Im, Mi-Young [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873 (Korea, Republic of); Fischer, Peter, E-mail: PJFischer@lbl.gov [Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Santa Cruz, California 94056 (United States)

    2015-05-07

    The spectroscopic analysis of X-ray magnetic circular dichroism (XMCD), which serves as strong and element-specific magnetic contrast in full-field magnetic transmission soft x-ray microscopy, is shown to provide information on the local distribution of spin (S) and orbital (L) magnetic moments down to a spatial resolution of 25 nm limited by the x-ray optics used in the x-ray microscope. The spatially resolved L/S ratio observed in a multilayered (Co 0.3 nm/Pt 0.5 nm) × 30 thin film exhibiting a strong perpendicular magnetic anisotropy decreases significantly in the vicinity of domain walls, indicating a non-uniform spin configuration in the vertical profile of a domain wall across the thin film. Quantitative XMCD mapping with x-ray spectro-microscopy will become an important characterization tool for systems with topological or engineered magnetization inhomogeneities.

  20. Quantitative x-ray magnetic circular dichroism mapping with high spatial resolution full-field magnetic transmission soft x-ray spectro-microscopy

    International Nuclear Information System (INIS)

    The spectroscopic analysis of X-ray magnetic circular dichroism (XMCD), which serves as strong and element-specific magnetic contrast in full-field magnetic transmission soft x-ray microscopy, is shown to provide information on the local distribution of spin (S) and orbital (L) magnetic moments down to a spatial resolution of 25 nm limited by the x-ray optics used in the x-ray microscope. The spatially resolved L/S ratio observed in a multilayered (Co 0.3 nm/Pt 0.5 nm) × 30 thin film exhibiting a strong perpendicular magnetic anisotropy decreases significantly in the vicinity of domain walls, indicating a non-uniform spin configuration in the vertical profile of a domain wall across the thin film. Quantitative XMCD mapping with x-ray spectro-microscopy will become an important characterization tool for systems with topological or engineered magnetization inhomogeneities

  1. Quantitative x-ray magnetic circular dichroism mapping with high spatial resolution full-field magnetic transmission soft x-ray spectro-microscopy

    Science.gov (United States)

    Robertson, MacCallum J.; Agostino, Christopher J.; N'Diaye, Alpha T.; Chen, Gong; Im, Mi-Young; Fischer, Peter

    2015-05-01

    The spectroscopic analysis of X-ray magnetic circular dichroism (XMCD), which serves as strong and element-specific magnetic contrast in full-field magnetic transmission soft x-ray microscopy, is shown to provide information on the local distribution of spin (S) and orbital (L) magnetic moments down to a spatial resolution of 25 nm limited by the x-ray optics used in the x-ray microscope. The spatially resolved L/S ratio observed in a multilayered (Co 0.3 nm/Pt 0.5 nm) × 30 thin film exhibiting a strong perpendicular magnetic anisotropy decreases significantly in the vicinity of domain walls, indicating a non-uniform spin configuration in the vertical profile of a domain wall across the thin film. Quantitative XMCD mapping with x-ray spectro-microscopy will become an important characterization tool for systems with topological or engineered magnetization inhomogeneities.

  2. Altered human brain anatomy in chronic smokers: a review of magnetic resonance imaging studies.

    Science.gov (United States)

    Wang, Chao; Xu, Xiaojun; Qian, Wei; Shen, Zhujing; Zhang, Minming

    2015-04-01

    Cigarette smoking is becoming more prevalent in developing countries, such as China, and is the largest single cause of preventable death worldwide. New emerging reports are highlighting how chronic cigarette smoking plays a role in neural dysfunctions, such as cognitive decline. Basic animal experimental studies have shown that rats undergo persistent pathological brain changes after being given chronic levels of nicotine. What is perhaps less appreciated is the fact that chronic cigarette smoking induces subtle anatomical changes in the human brain. Consequently, this chapter aims to summarize and integrate the existing magnetic resonance imaging studies on both gray- and white-matter marcostructural and microstructural changes. The reviewed studies demonstrate that chronic cigarette smoking results in discrete and localized alterations in brain region tissue (both the gray and white matter of different brain regions), which may, in part, be responsible for different neural dysfunctions. In addition, we further discuss the possible pathological and neurobiological mechanisms of these nicotinic effects on the brain tissue. We will also address the limitations of the current studies on this issue and identify opportunities for future research. PMID:25577510

  3. Magnetic resonance spectroscopy: novel non-invasive technique for diagnosing brain tumors

    International Nuclear Information System (INIS)

    To determine the accuracy of MR Spectroscopy (MRS) in diagnosing brain tumors. Study Design: Analytical study. Place and Duration of Study:Neurosurgery Department, Jinnah Postgraduate Medical Centre, Karachi, from November 2010 to April 2011. Methodology: Fifty cases with brain tumors, who presented to Neurosurgery Department of Jinnah Postgraduate Medical Centre, Karachi, during the study period, were included in the study. All patients underwent MRS and later brain. Those with recurrent disease were excluded. Data was collected with the help of proforma. Data was analyzed using SPSS version 16. Comparison of MRS findings and biopsy diagnosis was done. Sensitivity, specificity, negative and positive predictive values (NPV and PPV) were determined keeping histopathology as the gold standard. Results: Out of the 50 patients, there were 20 (40%) females and 30 (60%) males with mean age of 37 13.24 years. The commonest presenting complaint was headache (76%) followed by weakness (62%) and seizures (30%). MRI had diagnosed 27 (51%) as neoplastic lesion. Spectroscopy reported 44 (88%) as neoplasms, while on histopathology, 42 (84%) were confirmed to have neoplasm. The accuracy of MRS was 94%, with 97.6% sensitivity, 71.42% specificity, 95.45% PPV and 83.3% NPV. Conclusion: Magnetic resonance spectroscopy can readily help in differentiating neoplasm from non-neoplastic brain tumors, thus an invasive brain biopsy procedure can be avoided. (author)

  4. Review: magnetic resonance imaging of male/female differences in human adolescent brain anatomy

    Directory of Open Access Journals (Sweden)

    Giedd Jay N

    2012-08-01

    Full Text Available Abstract Improvements in neuroimaging technologies, and greater access to their use, have generated a plethora of data regarding male/female differences in the developing brain. Examination of these differences may shed light on the pathophysiology of the many illnesses that differ between the sexes and ultimately lead to more effective interventions. In this review, we attempt to synthesize the anatomic magnetic resonance imaging (MRI literature of male/female brain differences with emphasis on studies encompassing adolescence – a time of divergence in physical and behavioral characteristics. Across all ages total brain size is consistently reported to be about 10% larger in males. Structures commonly reported to be different between sexes include the caudate nucleus, amygdala, hippocampus, and cerebellum – all noted to have a relatively high density of sex steroid receptors. The direction and magnitude of reported brain differences depends on the methodology of data acquisition and analysis, whether and how the subcomponents are adjusted for the total brain volume difference, and the age of the participants in the studies. Longitudinal studies indicate regional cortical gray matter volumes follow inverted U shaped developmental trajectories with peak size occurring one to three years earlier in females. Cortical gray matter differences are modulated by androgen receptor genotyope and by circulating levels of hormones. White matter volumes increase throughout childhood and adolescence in both sexes but more rapidly in adolescent males resulting in an expanding magnitude of sex differences from childhood to adulthood.

  5. Magnetic resonance imaging of neonatal brain. Assessment of normal and abnormal findings

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Koh; Kadono, Naoko; Kawase, Shohji; Kihara, Minako; Matsuo, Yasutaka; Yoshioka, Hiroshi; Kinugasa, Akihiko; Sawada, Tadashi (Kyoto Prefectural Univ. of Medicine (Japan))

    1994-11-01

    To establish the normal MRI appearance of the neonatal brain, magnetic resonance imaging (MRI) was performed on 124 neonates who admitted to our neonatal intensive care unit. Degree of myelination, ventricular size, width of the extracerebral space and focal lesion in the brain were evaluated to investigate the relationship between MRI findings of neonatal brain and the neurological prognosis. 85 neonates underwent MRI both at neonatal period and at the corrected age of one year. The change of abnormal MRI findings was evaluated. 19 neonates had abnormal neurological outcome on subsequent examinations. Delayed myelination, ventriculomegaly and large extracerebral space were seen in 13, 7 and 9 neonates respectively. 4, 3 and 5 neonates out of them showed abnormal neurological prognosis respectively. Of the 19 neonates with focal lesion in MRI, 2 had parenchymal hematoma in the brain, 2 had subdural hematoma, 5 had chronic hematoma following subependymal hemorrhage, 6 had cystic formation following subependymal hemorrhage, 2 had subcortical leukomalacia, one had periventricular leukomalacia and one had cyst in the parenchyma of cerebellum. 4 neonates of 19 with focal lesion in MRI showed abnormal development. Of the neonates who had abnormal neurological prognosis, 7 neonates showed no abnormal finding in MRI at neonatal period. 3 of them had mild mental retardation. MRI shows promise in the neonatal period. It facilitates recognition of abnormalities of neonatal brain and may be used to predict abnormal neurologic outcome. However physiological change in the brain of neonates, especially of premature neonates, should be considered on interpreting these findings. Awareness of developmental features should help to minimize misinterpretation of normal changes in the neonatal brain. (author).

  6. Brain Phosphorus Magnetic Resonance Spectroscopy Imaging of Sleep Homeostasis and Restoration in Drug Dependence

    Directory of Open Access Journals (Sweden)

    George H. Trksak

    2007-01-01

    Full Text Available Numerous reports have documented a high occurrence of sleep difficulties in drug-dependent populations, prompting researchers to characterize sleep profiles and physiology in drug abusing populations. This mini-review examines studies indicating that drug-dependent populations exhibit alterations in sleep homeostatic and restoration processes in response to sleep deprivation. Sleep deprivation is a principal sleep research tool that results in marked physiological challenge, which provides a means to examine sleep homeostatic processes in response to extended wakefulness. A report from our laboratory demonstrated that following recovery sleep from sleep deprivation, brain high-energy phosphates particularly beta–nucleoside triphosphate (beta-NTP are markedly increased as measured with phosphorus magnetic resonance spectroscopy (MRS. A more recent study examined the effects of sleep deprivation in opiate-dependent methadone-maintained (MM subjects. The study demonstrated increases in brain beta-NTP following recovery sleep. Interestingly, these increases were of a markedly greater magnitude in MM subjects compared to control subjects. A similar study examined sleep deprivation in cocaine-dependent subjects demonstrating that cocaine-dependent subjects exhibit greater increases in brain beta-NTP following recovery sleep when compared to control subjects. The studies suggest that sleep deprivation in both MM subjects and cocaine-dependent subjects is characterized by greater changes in brain ATP levels than control subjects. Greater enhancements in brain ATP following recovery sleep may reflect a greater disruption to or impact of sleep deprivation in drug dependent subjects, whereby sleep restoration processes may be unable to properly regulate brain ATP and maintain brain high-energy equilibrium. These studies support the notion of a greater susceptibility to sleep loss in drug dependent populations. Additional sleep studies in drug abusing

  7. Feasibility of a novel design of high resolution parallax-free Compton enhanced PET scanner dedicated to brain research

    Energy Technology Data Exchange (ETDEWEB)

    Braem, A [CERN, PH Department, CH-1211 Geneva (Switzerland); Llatas, M Chamizo [Department of Corpuscular and Nuclear Physics, Geneva University, Geneva (Switzerland); Chesi, E [CERN, PH Department, CH-1211 Geneva (Switzerland); Correia, J G [Instituto Tecnologico e Nuclear, Sacavem (Portugal); Garibaldi, F [Instituto Superiore di Sanita, Roma (Italy); Joram, C [CERN, PH Department, CH-1211 Geneva (Switzerland); Mathot, S [CERN, PH Department, CH-1211 Geneva (Switzerland); Nappi, E [INFN, Sezione di Bari, Bari (Italy); Silva, M Ribeiro da [Centro de FIsica Nuclear da Universidade de Lisboa, Lisbon (Portugal); Schoenahl, F [Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland); Seguinot, J [CERN, PH Department, CH-1211 Geneva (Switzerland); Weilhammer, P [CERN, PH Department, CH-1211 Geneva (Switzerland); Zaidi, H [Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva (Switzerland)

    2004-06-21

    A novel concept for a positron emission tomography (PET) camera module is proposed, which provides full 3D reconstruction with high resolution over the total detector volume, free of parallax errors. The key components are a matrix of long scintillator crystals and hybrid photon detectors (HPDs) with matched segmentation and integrated readout electronics. The HPDs read out the two ends of the scintillator package. Both excellent spatial (x, y, z) and energy resolution are obtained. The concept allows enhancing the detection efficiency by reconstructing a significant fraction of events which underwent Compton scattering in the crystals. The proof of concept will first be demonstrated with yttrium orthoaluminate perovskite (YAP):Ce crystals, but the final design will rely on other scintillators more adequate for PET applications (e.g. LSO:Ce or LaBr{sub 3}:Ce). A promising application of the proposed camera module, which is currently under development, is a high resolution 3D brain PET camera with an axial field-of-view of {approx}15 cm dedicated to brain research. The design philosophy and performance predictions based on analytical calculations and Monte Carlo simulations are presented. Image correction and reconstruction tools required to operate this transmissionless device in a research environment are also discussed. Better or similar performance parameters were obtained compared to other known designs at lower fabrication cost. The axial geometrical concept also seems to be promising for applications such as positron emission mammography.

  8. Feasibility of a novel design of high resolution parallax-free Compton enhanced PET scanner dedicated to brain research

    Science.gov (United States)

    Braem, A.; Chamizo Llatas, M.; Chesi, E.; Correia, J. G.; Garibaldi, F.; Joram, C.; Mathot, S.; Nappi, E.; Ribeiro da Silva, M.; Schoenahl, F.; Séguinot, J.; Weilhammer, P.; Zaidi, H.

    2004-06-01

    A novel concept for a positron emission tomography (PET) camera module is proposed, which provides full 3D reconstruction with high resolution over the total detector volume, free of parallax errors. The key components are a matrix of long scintillator crystals and hybrid photon detectors (HPDs) with matched segmentation and integrated readout electronics. The HPDs read out the two ends of the scintillator package. Both excellent spatial (x, y, z) and energy resolution are obtained. The concept allows enhancing the detection efficiency by reconstructing a significant fraction of events which underwent Compton scattering in the crystals. The proof of concept will first be demonstrated with yttrium orthoaluminate perovskite (YAP):Ce crystals, but the final design will rely on other scintillators more adequate for PET applications (e.g. LSO:Ce or LaBr3:Ce). A promising application of the proposed camera module, which is currently under development, is a high resolution 3D brain PET camera with an axial field-of-view of ~15 cm dedicated to brain research. The design philosophy and performance predictions based on analytical calculations and Monte Carlo simulations are presented. Image correction and reconstruction tools required to operate this transmissionless device in a research environment are also discussed. Better or similar performance parameters were obtained compared to other known designs at lower fabrication cost. The axial geometrical concept also seems to be promising for applications such as positron emission mammography. All the authors are members of the CIMA Collaboration.

  9. BRAIN FUNCTIONAL IMAGING BASED ON BRAIN TISSUE OXYGEN CONTENT VIA MAGNETIC RESONANCE

    Directory of Open Access Journals (Sweden)

    M.A OGHABIAN

    2003-03-01

    Full Text Available Introduction: FMRI is a new approach in MRI to provide functional data of human brain activities. Some methods such as BOLD contrast, perfusion imaging, diffusion imaging, and spectroscopy in MRI have used to yield functional images. Material and Methods: This research was performed in imaging center of IMAM KHOMEINI hospital in TEHRAN in 1997. The experiments were performed on a conventional 1.5- T picker MR instrument, using a standard head coil. CE – FAST gradient echo images were obtained (TR=100, TE = 35, 128*256 matrix, 10 mm slice, FOV = 250 mm, F.A =25 Degree, NEX = 1, 13 s per image. Images were obtained during sensory - motor stimulation by pressing fingers to each other, coronal oblique images were acquired through central sulcus (precentral gyrus where the related sensory cortex is. Then, the Images were transferred to personal computers in order to eliminate noise and highlight the functional differences. These images were processed by various mathematical methods such as subtraction and student T- test. Results: Although some changes were seen in functional area, there were not significant results by the conventional system protocols. Some new protocols were designed and implemented to increase the sensitivity of the system to functional changes. Discussion: However, more research needs to be done in the future to obtain faster and more efficient techniques and in regard to clinical applications of the method.

  10. Assessing brain plasticity across the lifespan with transcranial magnetic stimulation: Why, how, and what is the ultimate goal?

    Directory of Open Access Journals (Sweden)

    Catarina eFreitas

    2013-04-01

    Full Text Available Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the XXI Century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally ‘normal’ brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual’s life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual’s brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS, which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index to enable objective correlates of an individual’s brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions.

  11. In vivo quantification of localized neuronal activation and inhibition in the rat brain using a dedicated high temporal-resolution β+-sensitive microprobe

    OpenAIRE

    Pain, Frédéric; Besret, Laurent; Vaufrey, Françoise; Grégoire, Marie-Claude; Pinot, Laurent; Gervais, Philippe; Ploux, Lydie; Bloch, Gilles; Mastrippolito, Roland; Lanièce, Philippe; Hantraye, Philippe

    2002-01-01

    Understanding brain disorders, the neural processes implicated in cognitive functions and their alterations in neurodegenerative pathologies, or testing new therapies for these diseases would benefit greatly from combined use of an increasing number of rodent models and neuroimaging methods specifically adapted to the rodent brain. Besides magnetic resonance (MR) imaging and functional MR, positron-emission tomography (PET) remains a unique methodology to study in vivo brain processes. Howeve...

  12. High-resolution characterisation of the aging brain using simultaneous quantitative susceptibility mapping (QSM) and R2* measurements at 7T.

    Science.gov (United States)

    Betts, Matthew J; Acosta-Cabronero, Julio; Cardenas-Blanco, Arturo; Nestor, Peter J; Düzel, Emrah

    2016-09-01

    Quantitative susceptibility mapping (QSM) has recently emerged as a novel magnetic resonance imaging (MRI) method to detect non-haem iron deposition, calcifications, demyelination and vascular lesions in the brain. It has been suggested that QSM is more sensitive than the more conventional quantifiable MRI measure, namely the transverse relaxation rate, R2*. Here, we conducted the first high-resolution, whole-brain, simultaneously acquired, comparative study of the two techniques using 7Tesla MRI. We asked which of the two techniques would be more sensitive to explore global differences in tissue composition in elderly adults relative to young subjects. Both QSM and R2* revealed strong age-related differences in subcortical regions, hippocampus and cortical grey matter, particularly in superior frontal regions, motor/premotor cortices, insula and cerebellar regions. Within the basal ganglia system-but also hippocampus and cerebellar dentate nucleus-, QSM was largely in agreement with R2* with the exception of the globus pallidus. QSM, however, provided superior anatomical contrast and revealed age-related differences in the thalamus and in white matter, which were otherwise largely undetected by R2* measurements. In contrast, in occipital cortex, age-related differences were much greater with R2* compared to QSM. The present study, therefore, demonstrated that in vivo QSM using ultra-high field MRI provides a novel means to characterise age-related differences in the human brain, but also combining QSM and R2* using multi-gradient recalled echo imaging can potentially provide a more complete picture of mineralisation, demyelination and/or vascular alterations in aging and disease. PMID:27181761

  13. Plasma Diagnostics in High Resolution X-Ray Spectra of Magnetic Cataclysmic Variables

    Energy Technology Data Exchange (ETDEWEB)

    Mauche, C W

    2001-10-02

    Using the Chandra HETG spectrum of EX Hya as an example, we discuss some of the plasma diagnostics available in high-resolution X-ray spectra of magnetic cataclysmic variables. Specifically, for conditions appropriate to collisional ionization equilibrium plasmas, we discuss the temperature dependence of the H- to He-like line intensity ratios and the density and photoexcitation dependence of the He-like R line ratios and the Fe XVII I(17.10 {angstrom})/I(17.05 {angstrom}) line ratio. We show that the plasma temperature in EX Hya spans the range from {approx}0.5 to {approx}10 keV and that the plasma density n {ge} 2 x 10{sup 14} cm{sup -3}, orders of magnitude greater than that observed in the Sun or other late-type stars.

  14. Measurement of Two Phase Flow in Porous Medium Using High-resolution Magnetic Resonance Imaging

    Institute of Scientific and Technical Information of China (English)

    JIANG Lanlan; SONG Yongchen; LIU Yu; YANG Mingjun; ZHU Ningjun; WANG Xiaojing; DOU Binlin

    2013-01-01

    Measurement of two phase flow in porous medium for sequestration was carried out using high-resolution magnetic resonance imaging (MRI) technique.The porous medium was a packed bed of glass beads.Spin echo multi sequence was used to measure the distribution of CO2 and water in the porous medium.The intensity images show that the fluid distribution is non-uniform due to its viscosity and pore structure of porous medium.The velocity distribution of fluids is calculated from the saturation of water and porosity of porous medium.The experimental results show that fluid velocities vary with time and position.The capillary dispersion rate donated the effects of capillary,which was largest at water saturations of 0.45.The displacement process is different between in BZ-02 and BZ-2.The final water residual saturation depends on permeability and porosity.

  15. Measurement of Fluid Flow in Pipe and Porous Media by High-Resolution Magnetic Resonance Imaging

    Institute of Scientific and Technical Information of China (English)

    JIANG Lan-lan; SONG Yong-chen; LIU Yu; DOU Bin-lin; ZHU Ning-jun; ZHAO Jia-fei; BULITI Abudula

    2012-01-01

    The objective of this study is to understand the process of fluid flow in pipe and porous media with different pore structures.High-resolution Magnetic Resonance Imaging (MRI) technique was used to visualize the pore structure and measure fluid flow.The porous media was formed by packed bed of glass beads.Flow measurement was carried out by a modified spin echo sequence.The results show that the velocity distribution in pipe is annular and the linear relation between MRI velocity and actual velocity is found in pipe flow measurement.The flow distribution in porous media is rather heterogeneous,and it is consistent with heterogeneous pore structure.The flow through pores with the high volume flow rate is determined largely by geometrical effects such as pore size and cross-sectional area.

  16. Flicker noise and magnetic resolution of graphene hall sensors at low frequency

    Science.gov (United States)

    Xu, Huilong; Huang, Le; Zhang, Zhiyong; Chen, Bingyan; Zhong, Hua; Peng, Lian-Mao

    2013-09-01

    Hall elements fabricated on chemical vapor deposited graphene exhibited high current- and voltage-related sensitivities due to its low intrinsic carrier density and high mobility about 5000 cm2/V s. Electric noise of the Hall elements was measured at room temperature and found to be largely Flicker noise at low frequency which can be well described by Hooge's empirical relation with a low noise parameter of about 1.8 × 10-4. The combination of high sensitivity and low noise in graphene Hall elements leads to a high room temperature magnetic resolution of about 5 × 10-3 G/Hz0.5 at 3 kHz.

  17. Continuous wave free precession Practical analytical tool for low-resolution nuclear magnetic resonance measurements

    International Nuclear Information System (INIS)

    The use of continuous wave free precession (CWFP) as a practical analytical tool for quantitative determinations in low-resolution nuclear magnetic resonance (LRNMR) is examined. The requirements of this technique are shown to be no more demanding than those prevailing in free-induction decay or spin-echo measurements. It is shown that the substantial gain in signal to noise ratio for a given acquisition time permitted by CWFP, can be exploited with advantage in practically any application of LRNMR. This applies not only to homogeneous low viscosity liquid samples but also to multi-component systems where differences in relaxation times of each component permit a separation of the individual contributions. As an example, the use of CWFP for fast quantitative determination of oil and moisture in various seeds is presented

  18. Development of a metallic magnetic calorimeter for high resolution spectroscopy; Entwicklung eines metallischen magnetischen Kalorimeters fuer die hochaufloesende Roentgenspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Linck, M.

    2007-05-02

    In this thesis the development of a metallic magnetic calorimeter for high resolution detection of single x-ray quanta is described. The detector consists of an X-ray absorber and a paramagnetic temperature sensor. The raise in temperature of the paramagnetic sensor due to the absorption of a single X-ray is measured by the change in magnetization of the sensor using a low-noise SQUID magnetometer. The thermodynamic properties of the detector can be described by a theoretical model based on a mean field approximation. This allows for an optimization of the detector design with respect to signal size. The maximal archivable energy resolution is limited by thermodynamic energy fluctuations between absorber, heat bath and thermometer. An interesting field of application for a metallic magnetic calorimeter is X-ray astronomy and the investigation of X-ray emitting objects. Through high-resolution X-ray spectroscopy it is possible to obtain information about physical processes of even far distant objects. The magnetic calorimeter that was developed in this thesis has a metallic absorber with a quantum efficiency of 98% at 6 keV. The energy resolution of the magnetic calorimeter is EFWHM=2.7 eV at 5.9 keV. The deviation of the detector response from a linear behavior of the detector is only 0.8% at 5.9 keV. (orig.)

  19. Using microcontact printing to fabricate microcoils on capillaries for high resolution proton nuclear magnetic resonance on nanoliter volumes

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.A.; Jackman, R.J.; Whitesides, G.M. [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Olson, D.L.; Sweedler, J.V. [Beckman Institute and Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    1997-05-01

    This letter describes a method for producing conducting microcoils for high resolution proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopy on nanoliter volumes. This technique uses microcontact printing and electroplating to form coils on microcapillaries. Nuclear magnetic resonance spectra collected using these microcoils, have linewidths less than 1 Hz for model compounds and a limit of detection (signal-to-noise ratio=3) for ethylbenzene of 2.6 nmol in 13 min. {copyright} {ital 1997 American Institute of Physics.}

  20. Functional magnetic resonance imaging and diffusion tensor tractography of the corticopontocerebellar tract in the human brain

    Institute of Scientific and Technical Information of China (English)

    Ji Heon Hong; Sung Ho Jang

    2011-01-01

    The anatomical organization of the corticopontocerebellar tract (CPCT) in the human brain remains poorly understood.The present study investigated probabilistic tractography of the CPCT in the human brain using diffusion tensor tractography with functional magnetic resonance imaging.CPCT data was obtained from 14 healthy subjects.CPCT images were obtained from functional magnetic resonance imaging and diffusion tensor tractography,revealing that the CPCT originated from the primary sensorimotor cortex and descended to the pontine nucleus through the corona radiata,the posterior limb of the internal capsule,and the cerebral peduncle.After crossing the pons through the transverse pontine fibers,the CPCT entered the cerebellum via the middle cerebral peduncle.However,some variation was detected in the midbrain (middle cerebral peduncle and/or medial lemniscus) and pons (ventral and/or dorsal transverse pontine fibers).The CPCT was analyzed in 3 dimensions from the cerebral cortex to the cerebellum.These results could be informative for future studies of motor control in the human brain.

  1. The EMPOWER Code: Electro-Magnetic Particle Operation With Enhanced Resolution

    Science.gov (United States)

    Karimabadi, H.; Omelchenko, Y. A.; Vu, H. X.

    2007-11-01

    Large-scale full PIC simulations play a crucial role in the modeling of laser-plasma interactions, accelerators, HPM devices and magnetic reconnection. These simulations ubiquitously employ uniform meshes, which severely limits their CPU speed and in many cases makes high-resolution runs prohibitive even on massively parallel computers. On the other hand, inadequate spatial resolution of realistic features (localized plasma volumes, device boundaries, etc.) is known to result in unacceptable errors. Structured adaptive mesh refinement (SAMR) has successfully been applied to fluid dynamics and MHD simulations. However, extending SAMR to practical electromagnetic particle-in-cell (PIC) models has proven to be nontrivial due to a number of additional numerical challenges, with spurious wave reflection and macro-particle self-force at the coarse-fine mesh interfaces being the most severe. These approximation errors typically result in a significant loss of simulation accuracy, energy/momentum non-conservation and long-time instabilities. We review our progress in resolving these issues in our new EM-PIC code, EMPOWER. We demonstrate the efficiency and accuracy of the new techniques on realistic examples related to simulations of high-power EM pulses and energetic particle beams.

  2. Relating speech production to tongue muscle compressions using tagged and high-resolution magnetic resonance imaging

    Science.gov (United States)

    Xing, Fangxu; Ye, Chuyang; Woo, Jonghye; Stone, Maureen; Prince, Jerry

    2015-03-01

    The human tongue is composed of multiple internal muscles that work collaboratively during the production of speech. Assessment of muscle mechanics can help understand the creation of tongue motion, interpret clinical observations, and predict surgical outcomes. Although various methods have been proposed for computing the tongue's motion, associating motion with muscle activity in an interdigitated fiber framework has not been studied. In this work, we aim to develop a method that reveals different tongue muscles' activities in different time phases during speech. We use fourdimensional tagged magnetic resonance (MR) images and static high-resolution MR images to obtain tongue motion and muscle anatomy, respectively. Then we compute strain tensors and local tissue compression along the muscle fiber directions in order to reveal their shortening pattern. This process relies on the support from multiple image analysis methods, including super-resolution volume reconstruction from MR image slices, segmentation of internal muscles, tracking the incompressible motion of tissue points using tagged images, propagation of muscle fiber directions over time, and calculation of strain in the line of action, etc. We evaluated the method on a control subject and two postglossectomy patients in a controlled speech task. The normal subject's tongue muscle activity shows high correspondence with the production of speech in different time instants, while both patients' muscle activities show different patterns from the control due to their resected tongues. This method shows potential for relating overall tongue motion to particular muscle activity, which may provide novel information for future clinical and scientific studies.

  3. An Ultra-High Field Magnetic Resonance Spectroscopy Study of Post Exercise Lactate, Glutamate and Glutamine Change in the Human Brain

    OpenAIRE

    Dennis, Andrea; Thomas, Adam G.; Rawlings, Nancy B.; Near, Jamie; Nichols, Thomas E.; Clare, Stuart; Johansen-Berg, Heidi; Stagg, Charlotte J.

    2015-01-01

    During strenuous exercise there is a progressive increase in lactate uptake and metabolism into the brain as workload and plasma lactate levels increase. Although it is now widely accepted that the brain can metabolize lactate, few studies have directly measured brain lactate following vigorous exercise. Here, we used ultra-high field magnetic resonance spectroscopy of the brain to obtain static measures of brain lactate, as well as brain glutamate and glutamine after vigorous exercise. The a...

  4. A high resolution electrostatic time-of-flight spectrometer with adiabatic magnetic collimation

    CERN Document Server

    Bonn, J; Degen, B; Otten, E W; Weinheimer, C

    1999-01-01

    A new type of spectrometer for low energy charged particles is presented. It consists of an adiabatic magnetic collimation and two filters: an electrostatic retarding potential to set a lower limit (high pass) and a time-of-flight analysis to reject high energy charged particles (low pass). Both filters are only limited in their resolution by the efficiency of the adiabatic magnetic collimation. The proof of this principle is demonstrated by a pilot measurement on the K conversion line of sup 8 sup 3 sup m Kr. Possible applications to pulsed and continuous electron sources are discussed with the emphasis on the investigation of the beta spectrum of T sub 2 to deduce information on the mass of the electron antineutrino and possible anomalies in the beta spectrum. In this context design parameters of a spectrometer with a resolving power of E/DELTA E=20 000 and a luminosity of A DELTA OMEGA/4 pi=4 cm sup 2 for 20 keV electrons are given.

  5. Amyloids in solid-state nuclear magnetic resonance: potential causes of the usually low resolution

    Directory of Open Access Journals (Sweden)

    Espargaró A

    2015-11-01

    Full Text Available Alba Espargaró, Maria Antònia Busquets, Joan Estelrich, Raimon Sabate Department of Physical Chemistry, School of Pharmacy, Institute of Nanoscience and Nanotechnology (IN2UB, University of Barcelona, Barcelona, Spain Abstract: Amyloids are non-crystalline and insoluble, which imply that the classical structural biology tools, ie, X-ray crystallography and solution nuclear magnetic resonance (NMR, are not suitable for their analysis. In the last years, solid-state NMR (ssNMR has emerged as an alternative tool to decrypt the structural signatures of amyloid fibrils, providing major contributions to our understanding of molecular structures of amyloids such as β-amyloid peptide associated with Alzheimer’s disease or fungal prions, among others. Despite this, the wide majority of amyloid fibrils display low resolution by ssNMR. Usually, this low resolution has been attributed to a high disorder or polymorphism of the fibrils, suggesting the existence of diverse elementary β-sheet structures. Here, we propose that a single β-sheet structure could be responsible for the broadening of the line widths in the ssNMR spectra. Although the fibrils and fibers consist of a single elementary structure, the angle of twist of each individual fibril in the mature fiber depends on the number of individual fibrils as well as the fibril arrangement in the final mature fiber. Thus, a wide range of angles of twist could be observed in the same amyloid sample. These twist variations involve changes in amino acid alignments that could be enough to limit the ssNMR resolution. Keywords: amyloid, fibril, misfolding, β-structure, ssNMR, NMR, β-sheet

  6. A consensus embedding approach for segmentation of high resolution in vivo prostate magnetic resonance imagery

    Science.gov (United States)

    Viswanath, Satish; Rosen, Mark; Madabhushi, Anant

    2008-03-01

    Current techniques for localization of prostatic adenocarcinoma (CaP) via blinded trans-rectal ultrasound biopsy are associated with a high false negative detection rate. While high resolution endorectal in vivo Magnetic Resonance (MR) prostate imaging has been shown to have improved contrast and resolution for CaP detection over ultrasound, similarity in intensity characteristics between benign and cancerous regions on MR images contribute to a high false positive detection rate. In this paper, we present a novel unsupervised segmentation method that employs manifold learning via consensus schemes for detection of cancerous regions from high resolution 1.5 Tesla (T) endorectal in vivo prostate MRI. A significant contribution of this paper is a method to combine multiple weak, lower-dimensional representations of high dimensional feature data in a way analogous to classifier ensemble schemes, and hence create a stable and accurate reduced dimensional representation. After correcting for MR image intensity artifacts, such as bias field inhomogeneity and intensity non-standardness, our algorithm extracts over 350 3D texture features at every spatial location in the MR scene at multiple scales and orientations. Non-linear dimensionality reduction schemes such as Locally Linear Embedding (LLE) and Graph Embedding (GE) are employed to create multiple low dimensional data representations of this high dimensional texture feature space. Our novel consensus embedding method is used to average object adjacencies from within the multiple low dimensional projections so that class relationships are preserved. Unsupervised consensus clustering is then used to partition the objects in this consensus embedding space into distinct classes. Quantitative evaluation on 18 1.5 T prostate MR data against corresponding histology obtained from the multi-site ACRIN trials show a sensitivity of 92.65% and a specificity of 82.06%, which suggests that our method is successfully able to detect

  7. Angstrom-Resolution Magnetic Resonance Imaging of Single Molecules via Wave-Function Fingerprints of Nuclear Spins

    Science.gov (United States)

    Ma, Wen-Long; Liu, Ren-Bao

    2016-08-01

    Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom resolution of magnetic resonance imaging (MRI) are the highest challenges in magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR. Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes the "frequency fingerprints" of target nuclear spins. The frequency fingerprints by their nature cannot resolve different nuclear spins that have the same noise frequency or differentiate different types of correlations in nuclear-spin clusters, which limit the resolution of single-molecule MRI. Here we show that this limitation can be overcome by using "wave-function fingerprints" of target nuclear spins, which is much more sensitive than the frequency fingerprints to the weak hyperfine interaction between the targets and a sensor under resonant DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable of counting and individually localizing single nuclear spins of the same frequency and characterizing the correlations in nuclear-spin clusters. A nitrogen-vacancy-center spin sensor near a diamond surface, provided that the coherence time is improved by surface engineering in the near future, may be employed to determine with angstrom resolution the positions and conformation of single molecules that are isotope labeled. The scheme in this work offers an approach to breaking the resolution limit set by the "frequency gradients" in conventional MRI and to reaching the angstrom-scale resolution.

  8. Three-Dimensional Magnetic Resonance Spectroscopic Imaging of Brain and Prostate Cancer

    Directory of Open Access Journals (Sweden)

    John Kurhanewicz

    2000-01-01

    Full Text Available Clinical applications of magnetic resonance spectroscopic imaging (MRSI for the study of brain and prostate cancer have expanded significantly over the past 10 years. Proton MRSI studies of the brain and prostate have demonstrated the feasibility of noninvasively assessing human cancers based on metabolite levels before and after therapy in a clinically reasonable amount of time. MRSI provides a unique biochemical “window” to study cellular metabolism noninvasively. MRSI studies have demonstrated dramatic spectral differences between normal brain tissue (low choline and high N-acetyl aspartate, NAA and prostate (low choline and high citrate compared to brain (low NAA, high choline and prostate (low citrate, high choline tumors. The presence of edema and necrosis in both the prostate and brain was reflected by a reduction of the intensity of all resonances due to reduced cell density. MRSI was able to discriminate necrosis (absence of all metabolites, except lipids and lactate from viable normal tissue and cancer following therapy. The results of current MRSI studies also provide evidence that the magnitude of metabolic changes in regions of cancer before therapy as well as the magnitude and time course of metabolic changes after therapy can improve our understanding of cancer aggressiveness and mechanisms of therapeutic response. Clinically, combined MRI/MRSI has already demonstrated the potential for improved diagnosis, staging and treatment planning of brain and prostate cancer. Additionally, studies are under way to determine the accuracy of anatomic and metabolic parameters in providing an objective quantitative basis for assessing disease progression and response to therapy.

  9. Novel aspects of brain metabolism as revealed by magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Full text: The techniques of Magnetic Resonance Spectroscopy (MRS) and Imaging (MRI) are outlined, and compared with Positron Emission Tomography (PET). Invasive PET techniques using 19F-fluorodeoxyglucose (FDG) and 18O2 form the main basis of brain activation studies, and with 19F-fluoroDOPA, make major contributions to studies on neurological disorders such as stroke, Alzheimer's disease and Parkinson's disease. However the technique has no chemical specificity so can provide no knowledge of intermediary metabolism. Non-invasive MRI is also being applied to brain activation studies but also has no chemical specificity. On the other hand MRS has superb chemical specificity, although it suffers from low sensitivity. A most interesting example of this is the use of 13C-MRS. If glucose is labelled on the no. 1 or no. 2 positions with 13C, the passage of the label through different neuronal and glial metabolic pathways can be followed. If acetate is similarly labelled, metabolic routes through specifically glial pathways can be monitored, since acetate is taken up only by glia. These studies contributed to knowledge on metabolic trafficking, in that glia produce alanine, citrate and lactate in addition to the previously characterised production of glutamine. Studies on the hypoxic brain revealed increased production of alanine, lactate and glycerol 3-phosphate, providing further understanding of the role of the NADH redox state. 'Isotopomer analysis' of 13C resonances provides more information on metabolic pathways, because the chemical shift of a 13C atom is specifically affected by a neighbouring 13C within the same molecule. This approach was used to demonstrate that neurotransmitter γ-aminobutyrate (GABA) is partly derived from glial glutamine. Analogous 13C MRS studies are now providing novel information on metabolic flux rates within the human brain, and the most exciting developments are to follow changes in these rates on brain activation which can be

  10. Implementation of magnetic resonance elastography for the investigation of traumatic brain injuries

    Science.gov (United States)

    Boulet, Thomas

    Magnetic resonance elastography (MRE) is a potentially transformative imaging modality allowing local and non-invasive measurement of biological tissue mechanical properties. It uses a specific phase contrast MR pulse sequence to measure induced vibratory motion in soft material, from which material properties can be estimated. Compared to other imaging techniques, MRE is able to detect tissue pathology at early stages by quantifying the changes in tissue stiffness associated with diseases. In an effort to develop the technique and improve its capabilities, two inversion algorithms were written to evaluate viscoelastic properties from the measured displacements fields. The first one was based on a direct algebraic inversion of the differential equation of motion, which decouples under certain simplifying assumptions, and featured a spatio-temporal multi-directional filter. The second one relies on a finite element discretization of the governing equations to perform a direct inversion. Several applications of this technique have also been investigated, including the estimation of mechanical parameters in various gel phantoms and polymers, as well as the use of MRE as a diagnostic tools for brain disorders. In this respect, the particular interest was to investigate traumatic brain injury (TBI), a complex and diverse injury affecting 1.7 million Americans annually. The sensitivity of MRE to TBI was first assessed on excised rat brains subjected to a controlled cortical impact (CCI) injury, before execution of in vivo experiments in mice. MRE was also applied in vivo on mouse models of medulloblastoma tumors and multiple sclerosis. These studies showed the potential of MRE in mapping the brain mechanically and providing non-invasive in vivo imaging markers for neuropathology and pathogenesis of brain diseases. Furthermore, MRE can easily be translatable to clinical settings; thus, while this technique may not be used directly to diagnose different abnormalities in

  11. High-resolution brain tumor visualization using three-dimensional x-ray phase contrast tomography.

    Science.gov (United States)

    Pfeiffer, F; Bunk, O; David, C; Bech, M; Le Duc, G; Bravin, A; Cloetens, P

    2007-12-01

    We report on significant advances and new results concerning a recently developed method for grating-based hard x-ray phase tomography. We demonstrate how the soft tissue sensitivity of the technique is increased and show in vitro tomographic images of a tumor bearing rat brain sample, without use of contrast agents. In particular, we observe that the brain tumor and the white and gray brain matter structure in a rat's cerebellum are clearly resolved. The results are potentially interesting from a clinical point of view, since a similar approach using three transmission gratings can be implemented with more readily available x-ray sources, such as standard x-ray tubes. Moreover, the results open the way to in vivo experiments in the near future. PMID:18029984

  12. Multigrid Nonlocal Gaussian Mixture Model for Segmentation of Brain Tissues in Magnetic Resonance Images

    Directory of Open Access Journals (Sweden)

    Yunjie Chen

    2016-01-01

    Full Text Available We propose a novel segmentation method based on regional and nonlocal information to overcome the impact of image intensity inhomogeneities and noise in human brain magnetic resonance images. With the consideration of the spatial distribution of different tissues in brain images, our method does not need preestimation or precorrection procedures for intensity inhomogeneities and noise. A nonlocal information based Gaussian mixture model (NGMM is proposed to reduce the effect of noise. To reduce the effect of intensity inhomogeneity, the multigrid nonlocal Gaussian mixture model (MNGMM is proposed to segment brain MR images in each nonoverlapping multigrid generated by using a new multigrid generation method. Therefore the proposed model can simultaneously overcome the impact of noise and intensity inhomogeneity and automatically classify 2D and 3D MR data into tissues of white matter, gray matter, and cerebral spinal fluid. To maintain the statistical reliability and spatial continuity of the segmentation, a fusion strategy is adopted to integrate the clustering results from different grid. The experiments on synthetic and clinical brain MR images demonstrate the superior performance of the proposed model comparing with several state-of-the-art algorithms.

  13. Evaluation of fetal brain development by magnetic resonance imaging. Subependymal germinal matrix layer and cerebral ventricle

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Yoshimasa; Yokota, Akira [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan); Okudera, Toshio

    1999-10-01

    Three dimensional data of brain from the formalin-fixed fetuses were collected without isolation, by the 4.7 tesla super high magnetic field MRI and the developmental process of the cerebral parenchyma was studied by 3D images. Subjects were 13 fetal brain and MRI was performed using 3D-steady-state free precession sequence. The isolated brain is very soft and fragile and is deformed by its weight at the imaging. However 3D-MRI can be obtained without isolation, and the deformation is remarkably small. The subependymal germinal matrix layer did not be observed in 7 weeks-old fetus, appeared at 9 weeks-old and increased gradually. Then it rapidly reduced from 28 weeks-old. The volume calculated, from 3D-MRI, increased rapidly from 9 weeks-old to 23 weeks-old, and reached the maximum (2.346 mm{sup 3}) at 23 weeks-old. The relation between fetal ages and volume of cerebral ventricle also showed similar pattern. This method will be useful to examine the development of the fetal brain without any damage. (K.H.)

  14. WAVELET STATISTICAL TEXTURE FEATURES WITH ORTHOGONAL OPERATORS TUMOUR CLASSIFICATION IN MAGNETIC RESONANCE IMAGING BRAIN

    Directory of Open Access Journals (Sweden)

    R. Meenakshi

    2013-01-01

    Full Text Available Tumors medically also called neoplasms are an abnormal mass of tissue resulting from uncontrolled proliferation or division of cells occurring in the human body. If such growth is located in the brain then it is called as brain tumor. Identification of such tumors is a major challenge in the field of medical science. Early identification of tumors prove to be critical as serious consequences can be averted. Its threat level depends on a combination of various factors like the type of tumor, its location, its size and its developmental stage. Tumor can occur in any part of the body. Magnetic Resonance Imaging (MRI technique is mainly used for analyzing the brain, as the images produced are of high precision and applicability. The main objective of this study is to classify the brain MRI dataset for the existence or non existence of tumors. The proposed method uses Two Dimensional Discrete Wavelet Transform (2D-DWT for pre-processing and further classification with orthogonal operators and SVM. The usage of 2D-DWT for pre-processing improves the classification accuracy by 2% when compared to the existing classification techniques.

  15. Volumetric Magnetic Resonance Imaging Study of Brain and Cerebellum in Children with Cerebral Palsy.

    Science.gov (United States)

    Kułak, Piotr; Maciorkowska, Elżbieta; Gościk, Elżbieta

    2016-01-01

    Introduction. Quantitative magnetic resonance imaging (MRI) studies are rarely used in the diagnosis of patients with cerebral palsy. The aim of present study was to assess the relationships between the volumetric MRI and clinical findings in children with cerebral palsy compared to control subjects. Materials and Methods. Eighty-two children with cerebral palsy and 90 age- and sex-matched healthy controls were collected. Results. The dominant changes identified on MRI scans in children with cerebral palsy were periventricular leukomalacia (42%) and posthemorrhagic hydrocephalus (21%). The total brain and cerebellum volumes in children with cerebral palsy were significantly reduced in comparison to controls. Significant grey matter volume reduction was found in the total brain in children with cerebral palsy compared with the control subjects. Positive correlations between the age of the children of both groups and the grey matter volumes in the total brain were found. Negative relationship between width of third ventricle and speech development was found in the patients. Positive correlations were noted between the ventricles enlargement and motor dysfunction and mental retardation in children with cerebral palsy. Conclusions. By using the voxel-based morphometry, the total brain, cerebellum, and grey matter volumes were significantly reduced in children with cerebral palsy. PMID:27579318

  16. Volumetric Magnetic Resonance Imaging Study of Brain and Cerebellum in Children with Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Piotr Kułak

    2016-01-01

    Full Text Available Introduction. Quantitative magnetic resonance imaging (MRI studies are rarely used in the diagnosis of patients with cerebral palsy. The aim of present study was to assess the relationships between the volumetric MRI and clinical findings in children with cerebral palsy compared to control subjects. Materials and Methods. Eighty-two children with cerebral palsy and 90 age- and sex-matched healthy controls were collected. Results. The dominant changes identified on MRI scans in children with cerebral palsy were periventricular leukomalacia (42% and posthemorrhagic hydrocephalus (21%. The total brain and cerebellum volumes in children with cerebral palsy were significantly reduced in comparison to controls. Significant grey matter volume reduction was found in the total brain in children with cerebral palsy compared with the control subjects. Positive correlations between the age of the children of both groups and the grey matter volumes in the total brain were found. Negative relationship between width of third ventricle and speech development was found in the patients. Positive correlations were noted between the ventricles enlargement and motor dysfunction and mental retardation in children with cerebral palsy. Conclusions. By using the voxel-based morphometry, the total brain, cerebellum, and grey matter volumes were significantly reduced in children with cerebral palsy.

  17. Volumetric Magnetic Resonance Imaging Study of Brain and Cerebellum in Children with Cerebral Palsy

    Science.gov (United States)

    Maciorkowska, Elżbieta; Gościk, Elżbieta

    2016-01-01

    Introduction. Quantitative magnetic resonance imaging (MRI) studies are rarely used in the diagnosis of patients with cerebral palsy. The aim of present study was to assess the relationships between the volumetric MRI and clinical findings in children with cerebral palsy compared to control subjects. Materials and Methods. Eighty-two children with cerebral palsy and 90 age- and sex-matched healthy controls were collected. Results. The dominant changes identified on MRI scans in children with cerebral palsy were periventricular leukomalacia (42%) and posthemorrhagic hydrocephalus (21%). The total brain and cerebellum volumes in children with cerebral palsy were significantly reduced in comparison to controls. Significant grey matter volume reduction was found in the total brain in children with cerebral palsy compared with the control subjects. Positive correlations between the age of the children of both groups and the grey matter volumes in the total brain were found. Negative relationship between width of third ventricle and speech development was found in the patients. Positive correlations were noted between the ventricles enlargement and motor dysfunction and mental retardation in children with cerebral palsy. Conclusions. By using the voxel-based morphometry, the total brain, cerebellum, and grey matter volumes were significantly reduced in children with cerebral palsy. PMID:27579318

  18. Brain nuclear magnetic resonance imaging enhanced by a paramagnetic nitroxide contrast agent: preliminary report. [Dogs

    Energy Technology Data Exchange (ETDEWEB)

    Brasch, R.C. (Univ. of California, San Francisco); Nitecki, D.E.; Brant-Zawadzki, M.; Enzmann, D.R.; Wesbey, G.E.; Tozer, T.N.; Tuck, L.D.; Cann, C.E.; Fike, J.R.; Sheldon, P.

    1983-11-01

    Contrast-enhancing agents for demonstrating abnormalities of the blood-brain barrier may extend the diagnostic utility of proton nuclear magnetic resonance (NMR) imaging. TES, a nitroxide stable free radical derivative, was tested as a central nervous system contrast enhancer in dogs with experimentally induced unilateral cerebritis or radiation cerebral damage. After intravenous injection of TES, the normal brain showed no change in NMR appearance, but areas of disease demonstrated a dramatic increase (up to 45%) in spin-echo intensity and a decrease in T/sub 1/, relaxation times. The areas of disease defined by TES enhancement were either not evident on the nonenhanced NMR images or were better defined after contrast administration. In-depth tests of toxicity, stability, and metabolism of this promising NMR contrast agent are now in progress.

  19. Brain nuclear magnetic resonance imaging enhanced by a paramagnetic nitroxide contrast agent: preliminary report

    International Nuclear Information System (INIS)

    Contrast-enhancing agents for demonstrating abnormalities of the blood-brain barrier may extend the diagnostic utility of proton nuclear magnetic resonance (NMR) imaging. TES, a nitroxide stable free radical derivative, was tested as a central nervous system contrast enhancer in dogs with experimentally induced unilateral cerebritis or radiation cerebral damage. After intravenous injection of TES, the normal brain showed no change in NMR appearance, but areas of disease demonstrated a dramatic increase (up to 45%) in spin-echo intensity and a decrease in T1, relaxation times. The areas of disease defined by TES enhancement were either not evident on the nonenhanced NMR images or were better defined after contrast administration. In-depth tests of toxicity, stability, and metabolism of this promising NMR contrast agent are now in progress

  20. Blind Source Separation of Hemodynamics from Magnetic Resonance Perfusion Brain Images Using Independent Factor Analysis

    Directory of Open Access Journals (Sweden)

    Yen-Chun Chou

    2010-01-01

    Full Text Available Perfusion magnetic resonance brain imaging induces temporal signal changes on brain tissues, manifesting distinct blood-supply patterns for the profound analysis of cerebral hemodynamics. We employed independent factor analysis to blindly separate such dynamic images into different maps, that is, artery, gray matter, white matter, vein and sinus, and choroid plexus, in conjunction with corresponding signal-time curves. The averaged signal-time curve on the segmented arterial area was further used to calculate the relative cerebral blood volume (rCBV, relative cerebral blood flow (rCBF, and mean transit time (MTT. The averaged ratios for rCBV, rCBF, and MTT between gray and white matters for normal subjects were congruent with those in the literature.

  1. In vivo measurement of water self diffusion in the human brain by magnetic resonance imaging

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1987-01-01

    A new pulse sequence for in vivo diffusion measurements by magnetic resonance imaging (MRI) is introduced. The pulse sequence was tested on phantoms to evaluate the accuracy, reproducibility and inplane variations. The sensitivity of the sequence was tested by measuring the self diffusion...... between grey and white matter as well as regional differences within the white matter were seen. In two patients with infarction, alternations in water self diffusion were seen in the region of the infarct. Likewise, pronounced changes in brain water self diffusion were observed in a patient with benign...... intracranial hypertension. The results indicate that brain water self diffusion can be measured in vivo with reasonable accuracy. The clinical examples suggest that diffusion measurements may be clinically useful adding further information about in vivo MR tissue characterization....

  2. Quantitative magnetic resonance imaging and studies of degenerative diseases of the developing human brain

    Energy Technology Data Exchange (ETDEWEB)

    Caviness, V.S. Jr. (Massachusetts General Hospital, Boston, MA (United States)); Phil, D.; Filipek, P.A.; Kennedy, D.N.

    1992-05-01

    The Rett syndrome is a progressive disorder which is associated with regression of psychomotor development and precipitous deceleration of brain growth during the first year of life. General histopathological surveys in postmortem specimens have identified degeneration of subpopulations of neurons of the nigrostriatal system but no other evidence of degenerative process. Magnetic resonance imaging-based morphometry may usefully guide application of rigorous but demanding quantitative histologic search for evidence of neuronal degeneration. The volumes of the principal set of cortical and nuclear structures of principal interest in the disorder may be measured by currently avaiable MRI-based methods. Opimized levels of precision now allow detection of volumetric changes over time in the same brain of approximately 10% at the 95% confidence level. (author).

  3. High temporal resolution magnetic resonance imaging: development of a parallel three dimensional acquisition method for functional neuroimaging

    International Nuclear Information System (INIS)

    Echo Planar Imaging is widely used to perform data acquisition in functional neuroimaging. This sequence allows the acquisition of a set of about 30 slices, covering the whole brain, at a spatial resolution ranging from 2 to 4 mm, and a temporal resolution ranging from 1 to 2 s. It is thus well adapted to the mapping of activated brain areas but does not allow precise study of the brain dynamics. Moreover, temporal interpolation is needed in order to correct for inter-slices delays and 2-dimensional acquisition is subject to vascular in flow artifacts. To improve the estimation of the hemodynamic response functions associated with activation, this thesis aimed at developing a 3-dimensional high temporal resolution acquisition method. To do so, Echo Volume Imaging was combined with reduced field-of-view acquisition and parallel imaging. Indeed, E.V.I. allows the acquisition of a whole volume in Fourier space following a single excitation, but it requires very long echo trains. Parallel imaging and field-of-view reduction are used to reduce the echo train durations by a factor of 4, which allows the acquisition of a 3-dimensional brain volume with limited susceptibility-induced distortions and signal losses, in 200 ms. All imaging parameters have been optimized in order to reduce echo train durations and to maximize S.N.R., so that cerebral activation can be detected with a high level of confidence. Robust detection of brain activation was demonstrated with both visual and auditory paradigms. High temporal resolution hemodynamic response functions could be estimated through selective averaging of the response to the different trials of the stimulation. To further improve S.N.R., the matrix inversions required in parallel reconstruction were regularized, and the impact of the level of regularization on activation detection was investigated. Eventually, potential applications of parallel E.V.I. such as the study of non-stationary effects in the B.O.L.D. response

  4. Globally conditioned Granger causality in brain-brain and brain-heart interactions: a combined heart rate variability/ultra-high-field (7 T) functional magnetic resonance imaging study.

    Science.gov (United States)

    Duggento, Andrea; Bianciardi, Marta; Passamonti, Luca; Wald, Lawrence L; Guerrisi, Maria; Barbieri, Riccardo; Toschi, Nicola

    2016-05-13

    The causal, directed interactions between brain regions at rest (brain-brain networks) and between resting-state brain activity and autonomic nervous system (ANS) outflow (brain-heart links) have not been completely elucidated. We collected 7 T resting-state functional magnetic resonance imaging (fMRI) data with simultaneous respiration and heartbeat recordings in nine healthy volunteers to investigate (i) the causal interactions between cortical and subcortical brain regions at rest and (ii) the causal interactions between resting-state brain activity and the ANS as quantified through a probabilistic, point-process-based heartbeat model which generates dynamical estimates for sympathetic and parasympathetic activity as well as sympathovagal balance. Given the high amount of information shared between brain-derived signals, we compared the results of traditional bivariate Granger causality (GC) with a globally conditioned approach which evaluated the additional influence of each brain region on the causal target while factoring out effects concomitantly mediated by other brain regions. The bivariate approach resulted in a large number of possibly spurious causal brain-brain links, while, using the globally conditioned approach, we demonstrated the existence of significant selective causal links between cortical/subcortical brain regions and sympathetic and parasympathetic modulation as well as sympathovagal balance. In particular, we demonstrated a causal role of the amygdala, hypothalamus, brainstem and, among others, medial, middle and superior frontal gyri, superior temporal pole, paracentral lobule and cerebellar regions in modulating the so-called central autonomic network (CAN). In summary, we show that, provided proper conditioning is employed to eliminate spurious causalities, ultra-high-field functional imaging coupled with physiological signal acquisition and GC analysis is able to quantify directed brain-brain and brain-heart interactions reflecting

  5. Magnetic dynamics studied by high-resolution electron spectroscopy and time-resolved electron microscopy

    Science.gov (United States)

    Jayaraman, Rajeswari

    Future information technology requires an increased magnetically encoded data density and novel electromagnetic modes of data transfer. While to date magnetic properties are observed and characterized mostly statically, the need emerges to monitor and capture their fast dynamics. In this talk, I will focus on the spin dynamics i.e. spin wave excitations and the dynamics of a new topological distribution of spins termed ``skyrmions''. Wave packets of spin waves offer the unique capability to transport a quantum bit, the spin, without the transport of charge or mass. Here, large wave-vector spin waves are of particular interest as they admit spin localization within a few nanometers. By using our recently developed electron energy loss spectrometer, we could study such spin waves in ultrathin films with an unprecedented energy resolution of 4 meV. By virtue of the finite penetration depth of low energy electrons, spin waves localized at interfaces between a substrate and a thin capping layer can be been studied yielding information about the exchange coupling between atoms at the interface. The quantization of spin waves with wave vectors perpendicular to the film gives rise to standing modes to which EELS has likewise access. Such studies when carried out as function of the film thickness again yield information on the layer dependence of the exchange coupling. Magnetic skyrmions are promising candidates as information carriers in logic or storage devices. Currently, little is known about the influence of disorder, defects, or external stimuli on the spatial distribution and temporal evolution of the skyrmion lattice. In this talk, I will describe the dynamical role of disorder in a large and flat thin film of Cu2OSeO3, exhibiting a skyrmion phase in an insulating material. We image up to 70,000 skyrmions by means of cryo-Lorentz Transmission Electron Microscopy as a function of the applied magnetic field. In the skyrmion phase, dislocations are shown to cause the

  6. Imaging diagnosis--magnetic resonance imaging findings in a dog with sequential brain infarction.

    Science.gov (United States)

    Major, Alison C; Caine, Abby; Rodriguez, Sue B; Cherubini, Giunio B

    2012-01-01

    An adult greyhound was evaluated on three occasions for acute, intracranial neurologic signs. Based on magnetic resonance (MR) imaging, there were T2-hyperintense and T1-hypointense, noncontrast enhancing lesions in the cerebellum, and brain stem. Using diffusion-weighted imaging (DWI), the lesions were characterized initially by restricted water diffusion. The presumptive diagnosis on each occasion was acute ischemic cerebrovascular accident leading to infarction. This allowed us to characterize the changes in appearance of infarcted neural tissue on the standard MR sequences over time, and to confirm that the DWI could be successfully used in low-field imaging. © 2012 Veterinary Radiology & Ultrasound. PMID:22731883

  7. Case control study: magnetic resonance spectroscopy of brain in HIV infected patients

    OpenAIRE

    Bairwa, Devender; Kumar, Virendra; Vyas, Surabhi; Das, Bimal Kumar; Srivastava, Achal Kumar; Pandey, Ravinder M.; Sharma, Surendra K; Jagannathan, Naranamangalam R.; Sinha, Sanjeev

    2016-01-01

    Background In vivo proton magnetic resonance spectroscopy (1H-MRS) studies on brain in HIV infected patients have shown significant alteration in neuro-biochemicals. Methods In this study, we measured the neuro-biochemical metabolites from the left frontal white matter (FWM) and left basal ganglia (BG) caudate head nucleus in 71 subjects that include 30 healthy controls, 20 asymptomatic HIV and 21 HIV patients with CNS lesion. Proton MR spectra were acquired at 3 T MRI system and the concentr...

  8. The use of magnetic resonance imaging to study the brain size of young children with autism

    Directory of Open Access Journals (Sweden)

    Farah Ashrafzadeh

    2016-07-01

    Full Text Available Introduction: Autism spectrum disorder (ASD is a syndrome of social communication deficits and repetitive behaviors or restricted interests. While the impairments associated with ASD tend to deteriorate from childhood into adulthood, it is of critical importance that the syndrome is diagnosed at an early age. One means of facilitating this is through understanding how the brain of people with ASD develops from early childhood. Magnetic resonance imaging (MRI is the method of choice for in vivo and non-invasive investigations of the morphology of the human brain, especially when the subjects are children. In this study, we conducted a systematic review of existing structural MRI studies that have investigated brain size in ASD children of up to 5 years old. Methods: In this study, we systematically reviewed published papers that describe research studies in which the brain size of ASD children has been examined. PubMed and Scopus databases were searched for all relevant original articles that described the use of MRI techniques to study ASD patients who were between 1 and 5 years old. To be included in the review, all studies needed to be cohort and case series that involved at least 10 patients. No time limitations were placed on the searched articles within the inclusion criteria. The exclusion criteria were non-English articles, case reports, and articles that described research involving subjects that were not within the qualifying age range of 1-5 years old.Result: After an initial screening process through which the title, abstracts, and full text of the articles were reviewed to confirm they met the inclusion criteria, a total of 10 relevant articles were studied in depth. All studies found that children with ASD who were within the selected age range had a larger brain size than children without ASD.Discussion: The findings of recent studies indicate that the vast majority of ASD patients exhibit an enlarged brain; however, the extent of

  9. Quantitative magnetic resonance imaging of the fetal brain in utero: Methods and applications

    Institute of Scientific and Technical Information of China (English)

    Anat; Biegon; Chen; Hoffmann

    2014-01-01

    Application of modern magnetic resonance imaging(MRI) techniques to the live fetus in utero is a relatively recent endeavor. The relative advantages and disadvantages of clinical MRI relative to the widely used and accepted ultrasonographic approach are the subject of a continuing debate; however the focus of this review is on the even younger field of quantitative MRI as applied to non-invasive studies of fetal brain development. The techniques covered under this header include structural MRI when followed by quan-titative(e.g., volumetric) analysis, as well as quantita-tive analyses of diffusion weighted imaging, diffusion tensor imaging, magnetic resonance spectroscopy and functional MRI. The majority of the published work re-viewed here reflects information gathered from normal fetuses scanned during the 3rd trimester, with relatively smaller number of studies of pathological samples including common congenital pathologies such as ven-triculomegaly and viral infection.

  10. Improvement of image resolution of brain SPECT by use of the wide-angle offset acquisition method

    International Nuclear Information System (INIS)

    Cerebral single photon emission computed tomography (SPECT) images require high spatial and contrast resolution for precise evaluation of the abnormal tracer distribution in the brain. A shorter data acquisition time is preferable so that artifacts due to patient movement are avoided. We tried to shorten data acquisition time applying larger sampling angle and offset acquisition method, in which half degree of the step angle was shifted in the opposite gamma camera of the dual-detector SPECT system. A simulation study was performed with a 3-dimensional mathematical phantom. The phantom studies were performed with a hot-rod phantom and a brain phantom. A clinical study with 99mTc-ECD SPECT was also performed on a patient who had a cerebral infarction. Reconstruction of images was done for the normal 6 deg and 12 deg onset and 12 deg offset. Data for the 12 deg offset were acquired by shifting of sampling angles of the opposite detector by half (6 deg) of the sampling angles of 12 deg. The maximum likelihood-expectation maximization (MLEM) algorithm was used for image reconstruction. Image qualities in the simulation study, the phantom studies, and the clinical study were compared for the 6 deg and 12 deg onset, and for the 12 deg offset by quantitative analysis with use of profile curves. Analysis of the profile curves revealed that the image quality of the 12 deg offset was better than that of the 12 deg onset and compared to that of the 6 deg onset in the simulation study, the phantom studies, and the clinical study. The present study indicates that wide-angle offset data acquisition improves the image resolution of brain SPECT compared to onset data acquisition with the same sampling time. (author)

  11. Brain Basics

    Medline Plus

    Full Text Available ... Research Modern research tools and techniques are giving scientists a more detailed understanding of the brain than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of the brain's structure, studies ...

  12. THE STUDY OF THE BRAIN IN A PATIENT WITH TYPE 1 DIABETES MELLITUS USING TECHNIQUES OF MAGNETIC RESONANCE IMAGING

    Directory of Open Access Journals (Sweden)

    Yu. G. Samoylova

    2015-12-01

    Full Text Available Type 1 diabetes mellitus (T1DM is now widely distributed worldwide and in theRussian Federation, it is an important medical and social problem in connection with the development of serious, disabling complications. Some of these complications could make changes in the brain which are accompanied by cognitive impairments that decrease quality of life and worsening disease compensation. The diagnosis of these disorders to date, possible by using modern methods of magnetic resonance imaging, which describe not only the morphological changes of the brain, but also the metabolism of nervous tissue. The study of the brain, namely structural and metabolic manifestations of diabetes, is one of the priority problem of modern medical science.The aim of the study was to evaluate dynamics in the different techniques of magnetic resonance imaging in the diagnosis of brain changes in patients with T1DM.Research methods included physical examination, in accordance with the diagnostic algorithm of patients with T1DM, a neurologist consultation, an assessment of cognitive function, analysis of brain changes using standard magnetic resonance imaging and spectroscopy. Statistical processing was performed using software package R-system. This publication presents a clinical case of a patient with T1DM and severe cognitive impairments are associated with changes in the brain, diagnosed using standard magnetic resonance imaging and spectroscopy. The study shows the positive role of correction of carbohydrate metabolism in improving cognitive function in a patient with T1DM.In addition, the process analysis revealed the absence of dynamic changes in the brain of a patient with T1DM according to standard magnetic resonance imaging. This required the use of additional techniques – magnetic resonance spectroscopy, which revealed changes of metabolism in the thalamus N-acetyl aspartate, choline and creatinine.

  13. Investigation of brain injury using in vivo multinuclear magnetic resonance imaging and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chew, W.M.

    1989-01-01

    Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) are becoming increasingly important tools to the fields of biochemistry, physiology, and medicine. MRI and MRS studies offer one the opportunity to obtain anatomic images and biochemical information non-invasively and non-destructively, thus making serial repeated measurements possible on the same experimental subject. To investigate brain injury, the non-invasiveness finally allows one to follow the time course of evolution of injury and its effects on the brains metabolism. Although MRI and MRS offer exciting opportunities, much work is needed to overcome the initial problems of signal localization from a specified region of interest. Also, the potential utility of multinuclear (i.e. {sup 13}C, {sup 19}F, {sup 23}Na...) MRI and MRS studies, in assessing brain injury, is yet to be determined. This thesis attacks the aforementioned problems with a series of studies both on phantoms and in vivo. Experiments were performed to determine optimal localization schemes for use in MRS of the brain to overcome the initial problems encountered with MRS studies. The feasibility and utility of multinuclear MRI and MRS was determined in vivo involving {sup 13}C, {sup 19}F, and {sup 23}Na nuclei. The results of these studies have proven that acceptable signal localization for MRS studies is achievable and is not a hindrance for future MRS studies. Also, multinuclear studies have shown that it is feasible to obtain MRI or MRS data from less abundant nuclei and that the information obtained does or can provide useful insights into brain metabolism in pathologic states.

  14. Localization of brain activity during auditory verbal short-term memory derived from magnetic recordings.

    Science.gov (United States)

    Starr, A; Kristeva, R; Cheyne, D; Lindinger, G; Deecke, L

    1991-09-01

    We have studied magnetic and electrical fields of the brain in normal subjects during the performance of an auditory verbal short-term memory task. On each trial 3 digits, selected from the numbers 'one' through 'nine', were presented for memorization followed by a probe number which could or could not be a member of the preceding memory set. The subject pressed an appropriate response button and accuracy and reaction time were measured. Magnetic fields recorded from up to 63 sites over both hemispheres revealed a transient field at 110 ms to both the memory item and the probe consistent with a dipole source in Heschl's gyrus; a sustained magnetic field between 300 and 800 ms to just the memory items localized to the temporal lobe slightly deeper and posterior to Heschl's gyri; and a sustained magnetic field between 300 and 800 ms to just the probes localized bilaterally to the medio-basal temporal lobes. These results are related to clinical disorders of short-term memory in man.

  15. High-Resolution Imaging and Optical Control of Bose-Einstein Condensates in an Atom Chip Magnetic Trap

    CERN Document Server

    Salim, Evan A; Pfeiffer, Jonathan B; Anderson, Dana Z

    2012-01-01

    A high-resolution projection and imaging system for ultracold atoms is implemented using a compound silicon and glass atom chip. The atom chip is metalized to enable magnetic trapping while glass regions enable high numerical aperture optical access to atoms residing in the magnetic trap about 100 microns below the chip surface. The atom chip serves as a wall of the vacuum system, which enables the use of commercial microscope components for projection and imaging. Holographically generated light patterns are used to optically slice a cigar-shaped magnetic trap into separate regions; this has been used to simultaneously generate up to four Bose-condensates. Using fluorescence techniques we have demonstrated in-trap imaging resolution down to 2.5 microns

  16. Biofouling-Resistant Impedimetric Sensor for Array High-Resolution Extracellular Potassium Monitoring in the Brain

    Directory of Open Access Journals (Sweden)

    Ruben Machado

    2016-10-01

    Full Text Available Extracellular potassium concentration, [K+]o, plays a fundamental role in the physiological functions of the brain. Studies investigating changes in [K+]o have predominantly relied upon glass capillary electrodes with K+-sensitive solution gradients for their measurements. However, such electrodes are unsuitable for taking spatio-temporal measurements and are limited by the surface area of their tips. We illustrate seizures invoked chemically and in optogenetically modified mice using blue light exposure while impedimetrically measuring the response. A sharp decrease of 1–2 mM in [K+]o before each spike has shown new physiological events not witnessed previously when measuring extracellular potassium concentrations during seizures in mice. We propose a novel approach that uses multichannel monolayer coated gold microelectrodes for in vivo spatio-temporal measurements of [K+]o in a mouse brain as an improvement to the conventional glass capillary electrode.

  17. 3-Dimensional modelling of chick embryo eye development and growth using high resolution magnetic resonance imaging.

    Science.gov (United States)

    Goodall, Nicola; Kisiswa, Lilian; Prashar, Ankush; Faulkner, Stuart; Tokarczuk, Paweł; Singh, Krish; Erichsen, Jonathan T; Guggenheim, Jez; Halfter, Willi; Wride, Michael A

    2009-10-01

    Magnetic resonance imaging (MRI) is a powerful tool for generating 3-dimensional structural and functional image data. MRI has already proven valuable in creating atlases of mouse and quail development. Here, we have exploited high resolution MRI to determine the parameters necessary to acquire images of the chick embryo eye. Using a 9.4 Tesla (400 MHz) high field ultra-shielded and refrigerated magnet (Bruker), MRI was carried out on paraformaldehyde-fixed chick embryos or heads at E4, E6, E8, and E10. Image data were processed using established and custom packages (MRICro, ImageJ, ParaVision, Bruker and mri3dX). Voxel dimensions ranged from 62.5 microm to 117.2 microm. We subsequently used the images obtained from the MRI data in order to make precise measurements of chick embryo eye surface area, volume and axial length from E4 to E10. MRI was validated for accurate sizing of ocular tissue features by direct comparison with previously published literature. Furthermore, we demonstrate the utility of high resolution MRI for making accurate measurements of morphological changes due to experimental manipulation of chick eye development, thereby facilitating a better understanding of the effects on chick embryo eye development and growth of such manipulations. Chondroitin sulphate or heparin were microinjected into the vitreous cavity of the right eyes of each of 3 embryos at E5. At E10, embryos were fixed and various eye parameters (volume, surface area, axial length and equatorial diameter) were determined using MRI and normalised with respect to the un-injected left eyes. Statistically significant alterations in eye volume (p < 0.05; increases with chondroitin sulphate and decreases with heparin) and changes in vitreous homogeneity were observed in embryos following microinjection of glycosaminoglycans. Furthermore, in the heparin-injected eyes, significant disturbances at the vitreo-retinal boundary were observed as well as retinal folding and detachment

  18. The Spokane fault, Washington, Imaged with High-Resolution Airborne Magnetic Data—Implications for the 2001 Spokane Earthquake Sequence

    Science.gov (United States)

    Blakely, R. J.; Sherrod, B. L.; Weaver, C. S.; Stephenson, W. J.

    2015-12-01

    A newly acquired, high-resolution aeromagnetic survey provides insights into the near-surface lithology and tectonic structure throughout the greater Spokane area of northeastern Washington and northwestern Idaho. The region has a diverse array of magnetic lithologies, ranging from highly magnetic flood basalts of the Columbia River Basalt Group (CRBG) to weakly magnetic Mesozoic plutonic and metamorphic rocks. Faults within these magnetic lithologies produce linear magnetic anomalies that permit mapping of geologic structures over tens of kilometers. A high-amplitude, linear magnetic anomaly overlies the NW- striking Cheney fracture zone 37 km southwest of Spokane and is interpreted as a basaltic dike swarm intruded during the extensional event that opened the fractures, possibly feeder dikes for overlying CRBG flows. A sub-parallel anomaly near the town of Cheney reflects another dike swarm, likely formed during the same extensional event. The Latah fault is seen as a discontinuous alignment of magnetic anomalies extending north-northwestward from south of Spokane to the northern edge of the magnetic survey, a distance of 44 km. An arcuate, north-striking magnetic lineament ~20 km northeast of Spokane may mark the Newport fault, the detachment that promoted exhumation of the Priest River metamorphic complex. A subtle northeast-striking magnetic lineament passes through downtown Spokane and may indicate the trace of the Spokane fault, suspected of producing more than 105 small (M≤4), shallow earthquakes within Spokane city limits in 2001, accompanied by 15 mm of vertical uplift. This magnetic lineament extends 22 km and, to the northwest, merges with the lineament interpreted as the Newport fault. The Spokane fault may represent a reactivated section of the Newport fault that otherwise is not known to be active today. New LiDAR data from the Spokane area does not show distinct fault scarps associated with these magnetic anomalies, but a more comprehensive

  19. 3-D Rat Brain Phantom for High-Resolution Molecular Imaging

    NARCIS (Netherlands)

    F.J. Beekman; B. Vastenhouw; G. van der Wilt; M. Vervloet; R. Visscher; J. Booij; M. Gerrits; C. Ji; R. Ramakers; F. van der Have

    2009-01-01

    With the steadily improving resolution of novel small-animal single photon emission computed tomography (SPECT) and positron emission tomography devices, highly detailed phantoms are required for testing and optimizing these systems. We present a three-dimensional (3-D) digital and physical phantom

  20. Feasibility of a novel design of high resolution parallax-free Compton enhanced PET scanner dedicated to brain research

    CERN Document Server

    Braem, André; Chesi, Enrico Guido; Correia, J G; Garibaldi, F; Joram, C; Mathot, S; Nappi, E; Ribeiro da Silva, M; Schoenahl, F; Séguinot, Jacques; Weilhammer, P; Zaidi, H

    2004-01-01

    A novel concept for a positron emission tomography (PET) camera module is proposed, which provides full 3D reconstruction with high resolution over the total detector volume, free of parallax errors. The key components are a matrix of long scintillator crystals and hybrid photon detectors (HPDs) with matched segmentation and integrated readout electronics. The HPDs read out the two ends of the scintillator package. Both excellent spatial (x, y, z) and energy resolution are obtained. The concept allows enhancing the detection efficiency by reconstructing a significant fraction of events which underwent Compton scattering in the crystals. The proof of concept will first be demonstrated with yttrium orthoaluminate perovskite (YAP):Ce crystals, but the final design will rely on other scintillators more adequate for PET applications (e.g. LSO:Ce or LaBr /sub 3/:Ce). A promising application of the proposed camera module, which is currently under development, is a high resolution 3D brain PET camera with an axial fi...

  1. Ultra-wide bore 900 MHz high-resolution NMR at the National High Magnetic Field Laboratory

    Science.gov (United States)

    Fu, R.; Brey, W. W.; Shetty, K.; Gor'kov, P.; Saha, S.; Long, J. R.; Grant, S. C.; Chekmenev, E. Y.; Hu, J.; Gan, Z.; Sharma, M.; Zhang, F.; Logan, T. M.; Brüschweller, R.; Edison, A.; Blue, A.; Dixon, I. R.; Markiewicz, W. D.; Cross, T. A.

    2005-11-01

    Access to an ultra-wide bore (105 mm) 21.1 T magnet makes possible numerous advances in NMR spectroscopy and MR imaging, as well as novel applications. This magnet was developed, designed, manufactured and tested at the National High Magnetic Field Laboratory and on July 21, 2004 it was energized to 21.1 T. Commercial and unique homebuilt probes, along with a standard commercial NMR console have been installed and tested with many science applications to develop this spectrometer as a user facility. Solution NMR of membrane proteins with enhanced resolution, new pulse sequences for solid state NMR taking advantage of narrowed proton linewidths, and enhanced spatial resolution and contrast leading to improved animal imaging have been documented. In addition, it is demonstrated that spectroscopy of single site 17O labeled macromolecules in a hydrated lipid bilayer environment can be recorded in a remarkably short period of time. 17O spectra of aligned samples show the potential for using this data for orientational restraints and for characterizing unique details of cation binding properties to ion channels. The success of this NHMFL magnet illustrates the potential for using a similar magnet design as an outsert for high temperature superconducting insert coils to achieve an NMR magnet with a field >25 T.

  2. High-resolution near-bottom vector magnetic anomalies over Raven Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge

    Science.gov (United States)

    Tivey, Maurice A.; Johnson, H. Paul; Salmi, Marie S.; Hutnak, Michael

    2014-10-01

    High-resolution, near-bottom vector magnetic data were collected by remotely operated vehicle Jason over the Raven hydrothermal vent field (47°57.3'N 129°5.75'W) located north of Main Endeavour vent field on the Endeavour segment of the Juan de Fuca Ridge. The survey was part of a comprehensive heat flow study of the Raven site using innovative thermal blanket technology to map the heat flux and crustal fluid pathways around a solitary hydrothermal vent field. Raven hydrothermal activity is presently located along the western axial valley wall, while additional inactive hydrothermal deposits are found to the NW on the upper rift valley wall. Magnetic inversion results show discrete areas of reduced magnetization associated with both active and inactive hydrothermal vent deposits that also show high conductive heat flow. Higher spatial variability in the heat flow patterns compared to the magnetization is consistent with the heat flow reflecting the currently active but ephemeral thermal environment of fluid flow, while crustal magnetization is representative of the static time-averaged effect of hydrothermal alteration. A general NW to SE trend in reduced magnetization across the Raven area correlates closely with the distribution of hydrothermal deposits and heat flux patterns and suggests that the fluid circulation system at depth is likely controlled by local crustal structure and magma chamber geometry. Magnetic gradient tensor components computed from vector magnetic data improve the resolution of the magnetic anomaly source and indicate that the hydrothermally altered zone directly beneath the Raven site is approximately 15 × 106 m3 in volume.

  3. Evidence for a "metabolically inactive" inorganic phosphate pool in adenosine triphosphate synthase reaction using localized 31P saturation transfer magnetic resonance spectroscopy in the rat brain at 11.7 T.

    Science.gov (United States)

    Tiret, Brice; Brouillet, Emmanuel; Valette, Julien

    2016-09-01

    With the increased spectral resolution made possible at high fields, a second, smaller inorganic phosphate resonance can be resolved on (31)P magnetic resonance spectra in the rat brain. Saturation transfer was used to estimate de novo adenosine triphosphate synthesis reaction rate. While the main inorganic phosphate pool is used by adenosine triphosphate synthase, the second pool is inactive for this reaction. Accounting for this new pool may not only help us understand (31)P magnetic resonance spectroscopy metabolic profiles better but also better quantify adenosine triphosphate synthesis.

  4. Lesion localization of global aphasia without hemiparesis by overlapping of the brain magnetic resonance images

    Institute of Scientific and Technical Information of China (English)

    Woo Jin Kim; Nam-Jong Paik

    2014-01-01

    Global aphasia without hemiparesis is a striking stroke syndrome involving language impairment without the typically manifested contralateral hemiparesis, which is usually seen in patients with global aphasia following large left perisylvian lesions. The objective of this study is to elucidate the speciifc areas for lesion localization of global aphasia without hemiparesis by retrospectively studying the brain magnetic resonance images of six patients with global aphasia without hemi-paresis to deifne global aphasia without hemiparesis-related stroke lesions before overlapping the images to visualize the most overlapped area. Talairach coordinates for the most overlapped areas were converted to corresponding anatomical regions. Lesions where the images of more than three patients overlapped were considered significant. The overlapped global aphasia without hemiparesis related stroke lesions of six patients revealed that the signiifcantly involved anatomi-cal lesions were as follows:frontal lobe, sub-gyral, sub-lobar, extra-nuclear, corpus callosum, and inferior frontal gyrus, while caudate, claustrum, middle frontal gyrus, limbic lobe, temporal lobe, superior temporal gyrus, uncus, anterior cingulate, parahippocampal, amygdala, and subcallosal gyrus were seen less signiifcantly involved. This study is the ifrst to demonstrate the heteroge-neous anatomical involvement in global aphasia without hemiparesis by overlapping of the brain magnetic resonance images.

  5. Detection of cerebral atrophy in type- II diabetes mellitus by magnetic resonance imaging of brain

    International Nuclear Information System (INIS)

    Background: Diabetes is a metabolic disorder that affects many systems in the body. Cerebral atrophy is one of the complications of diabetes and research is on going to find out its aetiopathological factors. The main aim of the study was to determine the frequency of cerebral atrophy in type-II diabetes mellitus using magnetic resonance imaging of the brain. Methods: One hundred diabetic patients (Random blood sugar >126 mg/dl) were recruited in this study after the informed consent from every patient. Duration of diabetes was five years and more in all the patients as determined by their glycosylated haemoglobin which was >6 in all the patients. All the patients were undergone MRI of brain using 1.5 Tesla power magnetic resonance imaging machine of Picker Company. Evan's index, a specific parameter for measurement of cerebral atrophy was calculated on MR images and was used in this study. Results: In male group the frequency of cerebral atrophy was 22 (47%) and in female group it was found to be 23 (43%). When we study the overall population the frequency was found to be 45 (45%). The results are well in concordance with the previous data published on this issue. Conclusions: Cerebral atrophy, a complication of long standing diabetes is quite frequent in our population and is well diagnosed by MRI. (author)

  6. MR_CHIROD v.2: magnetic resonance compatible smart hand rehabilitation device for brain imaging.

    Science.gov (United States)

    Khanicheh, Azadeh; Mintzopoulos, Dionyssios; Weinberg, Brian; Tzika, A Aria; Mavroidis, Constantinos

    2008-02-01

    This paper presents the design, fabrication, and testing of a novel, one degree-of-freedom, magnetic resonance compatible smart hand interfaced rehabilitation device (MR_CHIROD v.2), which may be used in brain magnetic resonance (MR) imaging during handgrip rehabilitation. A key feature of the device is the use of electrorheological fluids (ERFs) to achieve computer controlled, variable, and tunable resistive force generation. The device consists of three major subsystems: 1) an ERF based resistive element, 2) handles, and c) two sensors, one optical encoder and one force sensor, to measure the patient induced motion and force. MR_CHIROD v.2 is designed to resist up to 50% of the maximum level of gripping force of a human hand and be controlled in real time. Our results demonstrate that the MR environment does not interfere with the performance of the MR_CHIROD v.2, and, reciprocally, its use does not cause fMR image artifacts. The results are encouraging in jointly using MR_CHIROD v.2 and brain MR imaging to study motor performance and assess rehabilitation after neurological injuries such as stroke. PMID:18303810

  7. Acute ischaemic brain lesions in intracerebral haemorrhage: multicentre cross-sectional magnetic resonance imaging study.

    Science.gov (United States)

    Gregoire, Simone M; Charidimou, Andreas; Gadapa, Naveen; Dolan, Eamon; Antoun, Nagui; Peeters, Andre; Vandermeeren, Yves; Laloux, Patrice; Baron, Jean-Claude; Jäger, Hans R; Werring, David J

    2011-08-01

    Subclinical acute ischaemic lesions on brain magnetic resonance imaging have recently been described in spontaneous intracerebral haemorrhage, and may be important to understand pathophysiology and guide treatment. The underlying mechanisms are uncertain. We tested the hypothesis that ischaemic lesions are related to magnetic resonance imaging markers of the severity and type of small-vessel disease (hypertensive arteriopathy or cerebral amyloid angiopathy) in a multicentre, cross-sectional study. We studied consecutive patients with intracerebral haemorrhage from four specialist stroke centres, and age-matched stroke service referrals without intracerebral haemorrhage. Acute ischaemic lesions were assessed on magnetic resonance imaging (imaging. White matter changes and cerebral microbleeds were rated with validated scales. We investigated associations between diffusion-weighted imaging lesions, clinical and radiological characteristics. We included 114 patients with intracerebral haemorrhage (39 with clinically probable cerebral amyloid angiopathy) and 47 age-matched controls. The prevalence of diffusion-weighted imaging lesions was 9/39 (23%) in probable cerebral amyloid angiopathy-related intracerebral haemorrhage versus 6/75 (8%) in the remaining patients with intracerebral haemorrhage (P = 0.024); no diffusion-weighted imaging lesions were found in controls. Diffusion-weighted imaging lesions were mainly cortical and were associated with mean white matter change score (odds ratio 1.14 per unit increase, 95% confidence interval 1.02-1.28, P = 0.024) and the presence of strictly lobar cerebral microbleeds (odds ratio 3.85, 95% confidence interval 1.15-12.93, P = 0.029). Acute, subclinical ischaemic brain lesions are frequent but previously underestimated after intracerebral haemorrhage, and are three times more common in cerebral amyloid angiopathy-related intracerebral haemorrhage than in other intracerebral haemorrhage types. Ischaemic brain lesions are

  8. Magnetoacoustic tomography with magnetic induction for high-resolution bioimepedance imaging through vector source reconstruction under the static field of MRI magnet

    Energy Technology Data Exchange (ETDEWEB)

    Mariappan, Leo; Hu, Gang [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 (United States); He, Bin, E-mail: binhe@umn.edu [Department of Biomedical Engineering, University of Minnesota, Minnesota 55455 and Institute of Engineering in Medicine, University of Minnesota, Minnesota 55455 (United States)

    2014-02-15

    Purpose: Magnetoacoustic tomography with magnetic induction (MAT-MI) is an imaging modality to reconstruct the electrical conductivity of biological tissue based on the acoustic measurements of Lorentz force induced tissue vibration. This study presents the feasibility of the authors' new MAT-MI system and vector source imaging algorithm to perform a complete reconstruction of the conductivity distribution of real biological tissues with ultrasound spatial resolution. Methods: In the present study, using ultrasound beamformation, imaging point spread functions are designed to reconstruct the induced vector source in the object which is used to estimate the object conductivity distribution. Both numerical studies and phantom experiments are performed to demonstrate the merits of the proposed method. Also, through the numerical simulations, the full width half maximum of the imaging point spread function is calculated to estimate of the spatial resolution. The tissue phantom experiments are performed with a MAT-MI imaging system in the static field of a 9.4 T magnetic resonance imaging magnet. Results: The image reconstruction through vector beamformation in the numerical and experimental studies gives a reliable estimate of the conductivity distribution in the object with a ∼1.5 mm spatial resolution corresponding to the imaging system frequency of 500 kHz ultrasound. In addition, the experiment results suggest that MAT-MI under high static magnetic field environment is able to reconstruct images of tissue-mimicking gel phantoms and real tissue samples with reliable conductivity contrast. Conclusions: The results demonstrate that MAT-MI is able to image the electrical conductivity properties of biological tissues with better than 2 mm spatial resolution at 500 kHz, and the imaging with MAT-MI under a high static magnetic field environment is able to provide improved imaging contrast for biological tissue conductivity reconstruction.

  9. Brain tissue segmentation using q-entropy in multiple sclerosis magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, P.R.B.; Brum, D.G. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Neurociencias e Ciencias do Comportamento; Santos, A. C. [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Clinica Medica; Murta-Junior, L.O.; Araujo, D.B. de, E-mail: murta@usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2010-01-15

    The loss of brain volume has been used as a marker of tissue destruction and can be used as an index of the progression of neurodegenerative diseases, such as multiple sclerosis. In the present study, we tested a new method for tissue segmentation based on pixel intensity threshold using generalized Tsallis entropy to determine a statistical segmentation parameter for each single class of brain tissue. We compared the performance of this method using a range of different q parameters and found a different optimal q parameter for white matter, gray matter, and cerebrospinal fluid. Our results support the conclusion that the differences in structural correlations and scale invariant similarities present in each tissue class can be accessed by generalized Tsallis entropy, obtaining the intensity limits for these tissue class separations. In order to test this method, we used it for analysis of brain magnetic resonance images of 43 patients and 10 healthy controls matched for gender and age. The values found for the entropic q index were 0.2 for cerebrospinal fluid, 0.1 for white matter and 1.5 for gray matter. With this algorithm, we could detect an annual loss of 0.98% for the patients, in agreement with literature data. Thus, we can conclude that the entropy of Tsallis adds advantages to the process of automatic target segmentation of tissue classes, which had not been demonstrated previously. (author)

  10. Lesion detection in magnetic resonance brain images by hyperspectral imaging algorithms

    Science.gov (United States)

    Xue, Bai; Wang, Lin; Li, Hsiao-Chi; Chen, Hsian Min; Chang, Chein-I.

    2016-05-01

    Magnetic Resonance (MR) images can be considered as multispectral images so that MR imaging can be processed by multispectral imaging techniques such as maximum likelihood classification. Unfortunately, most multispectral imaging techniques are not particularly designed for target detection. On the other hand, hyperspectral imaging is primarily developed to address subpixel detection, mixed pixel classification for which multispectral imaging is generally not effective. This paper takes advantages of hyperspectral imaging techniques to develop target detection algorithms to find lesions in MR brain images. Since MR images are collected by only three image sequences, T1, T2 and PD, if a hyperspectral imaging technique is used to process MR images it suffers from the issue of insufficient dimensionality. To address this issue, two approaches to nonlinear dimensionality expansion are proposed, nonlinear correlation expansion and nonlinear band ratio expansion. Once dimensionality is expanded hyperspectral imaging algorithms are readily applied. The hyperspectral detection algorithm to be investigated for lesion detection in MR brain is the well-known subpixel target detection algorithm, called Constrained Energy Minimization (CEM). In order to demonstrate the effectiveness of proposed CEM in lesion detection, synthetic images provided by BrainWeb are used for experiments.

  11. Brain tissue segmentation using q-entropy in multiple sclerosis magnetic resonance images

    Directory of Open Access Journals (Sweden)

    P.R.B. Diniz

    2010-01-01

    Full Text Available The loss of brain volume has been used as a marker of tissue destruction and can be used as an index of the progression of neurodegenerative diseases, such as multiple sclerosis. In the present study, we tested a new method for tissue segmentation based on pixel intensity threshold using generalized Tsallis entropy to determine a statistical segmentation parameter for each single class of brain tissue. We compared the performance of this method using a range of different q parameters and found a different optimal q parameter for white matter, gray matter, and cerebrospinal fluid. Our results support the conclusion that the differences in structural correlations and scale invariant similarities present in each tissue class can be accessed by generalized Tsallis entropy, obtaining the intensity limits for these tissue class separations. In order to test this method, we used it for analysis of brain magnetic resonance images of 43 patients and 10 healthy controls matched for gender and age. The values found for the entropic q index were 0.2 for cerebrospinal fluid, 0.1 for white matter and 1.5 for gray matter. With this algorithm, we could detect an annual loss of 0.98% for the patients, in agreement with literature data. Thus, we can conclude that the entropy of Tsallis adds advantages to the process of automatic target segmentation of tissue classes, which had not been demonstrated previously.

  12. Uptake of dimercaptosuccinate-coated magnetic iron oxide nanoparticles by cultured brain astrocytes

    Science.gov (United States)

    Geppert, Mark; Hohnholt, Michaela C.; Thiel, Karsten; Nürnberger, Sylvia; Grunwald, Ingo; Rezwan, Kurosch; Dringen, Ralf

    2011-04-01

    Magnetic iron oxide nanoparticles (Fe-NP) are currently considered for various diagnostic and therapeutic applications in the brain. However, little is known on the accumulation and biocompatibility of such particles in brain cells. We have synthesized and characterized dimercaptosuccinic acid (DMSA) coated Fe-NP and have investigated their uptake by cultured brain astrocytes. DMSA-coated Fe-NP that were dispersed in physiological medium had an average hydrodynamic diameter of about 60 nm. Incubation of cultured astrocytes with these Fe-NP caused a time- and concentration-dependent accumulation of cellular iron, but did not lead within 6 h to any cell toxicity. After 4 h of incubation with 100-4000 µM iron supplied as Fe-NP, the cellular iron content reached levels between 200 and 2000 nmol mg - 1 protein. The cellular iron content after exposure of astrocytes to Fe-NP at 4 °C was drastically lowered compared to cells that had been incubated at 37 °C. Electron microscopy revealed the presence of Fe-NP-containing vesicles in cells that were incubated with Fe-NP at 37 °C, but not in cells exposed to the nanoparticles at 4 °C. These data demonstrate that cultured astrocytes efficiently take up DMSA-coated Fe-NP in a process that appears to be saturable and strongly depends on the incubation temperature.

  13. Uptake of dimercaptosuccinate-coated magnetic iron oxide nanoparticles by cultured brain astrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Geppert, Mark; Hohnholt, Michaela C; Dringen, Ralf [Center for Biomolecular Interactions Bremen, University of Bremen, PO Box 330440, D-28334 Bremen (Germany); Thiel, Karsten; Grunwald, Ingo [Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Wiener Strasse 12, D-28359 Bremen (Germany); Nuernberger, Sylvia [Department of Traumatology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Rezwan, Kurosch, E-mail: ralf.dringen@uni-bremen.de [Advanced Ceramics, University of Bremen, Am Biologischen Garten 2, D-28359 Bremen (Germany)

    2011-04-08

    Magnetic iron oxide nanoparticles (Fe-NP) are currently considered for various diagnostic and therapeutic applications in the brain. However, little is known on the accumulation and biocompatibility of such particles in brain cells. We have synthesized and characterized dimercaptosuccinic acid (DMSA) coated Fe-NP and have investigated their uptake by cultured brain astrocytes. DMSA-coated Fe-NP that were dispersed in physiological medium had an average hydrodynamic diameter of about 60 nm. Incubation of cultured astrocytes with these Fe-NP caused a time- and concentration-dependent accumulation of cellular iron, but did not lead within 6 h to any cell toxicity. After 4 h of incubation with 100-4000 {mu}M iron supplied as Fe-NP, the cellular iron content reached levels between 200 and 2000 nmol mg{sup -1} protein. The cellular iron content after exposure of astrocytes to Fe-NP at 4 deg. C was drastically lowered compared to cells that had been incubated at 37 deg. C. Electron microscopy revealed the presence of Fe-NP-containing vesicles in cells that were incubated with Fe-NP at 37 deg. C, but not in cells exposed to the nanoparticles at 4 deg. C. These data demonstrate that cultured astrocytes efficiently take up DMSA-coated Fe-NP in a process that appears to be saturable and strongly depends on the incubation temperature.

  14. Uptake of dimercaptosuccinate-coated magnetic iron oxide nanoparticles by cultured brain astrocytes

    International Nuclear Information System (INIS)

    Magnetic iron oxide nanoparticles (Fe-NP) are currently considered for various diagnostic and therapeutic applications in the brain. However, little is known on the accumulation and biocompatibility of such particles in brain cells. We have synthesized and characterized dimercaptosuccinic acid (DMSA) coated Fe-NP and have investigated their uptake by cultured brain astrocytes. DMSA-coated Fe-NP that were dispersed in physiological medium had an average hydrodynamic diameter of about 60 nm. Incubation of cultured astrocytes with these Fe-NP caused a time- and concentration-dependent accumulation of cellular iron, but did not lead within 6 h to any cell toxicity. After 4 h of incubation with 100-4000 μM iron supplied as Fe-NP, the cellular iron content reached levels between 200 and 2000 nmol mg-1 protein. The cellular iron content after exposure of astrocytes to Fe-NP at 4 deg. C was drastically lowered compared to cells that had been incubated at 37 deg. C. Electron microscopy revealed the presence of Fe-NP-containing vesicles in cells that were incubated with Fe-NP at 37 deg. C, but not in cells exposed to the nanoparticles at 4 deg. C. These data demonstrate that cultured astrocytes efficiently take up DMSA-coated Fe-NP in a process that appears to be saturable and strongly depends on the incubation temperature.

  15. Impaired cognitive functions in mild traumatic brain injury patients with normal and pathologic magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kurca, E.; Sivak, S. [Comenius University, Clinic of Neurology, Jessenius Faculty of Medicine, Martin (Slovakia); Kucera, P. [Comenius University, 1st Clinic of Neurology, Faculty of Medicine, Bratislava (Slovakia)

    2006-09-15

    Mild traumatic brain injury (MTBI) is a common neurological (neurotraumatological) diagnosis. As well as different subjective symptoms, many patients develop neuropsychological dysfunction with objective impairment of attention, memory and certain executive functions. Magnetic resonance imaging (MRI) is not routinely used in MTBI patients despite its proven greater sensitivity and specificity in comparison with computed tomography (CT). The patient group consisted of 30 persons with MTBI and the control group consisted of 30 sex- and age-matched healthy volunteers. Both groups underwent neurological examination, neuropsychological testing (including the Postconcussion Symptoms Scale questionnaire, PCSS) and brain MRI (the patient group within 96 h after injury). The analyzed groups did not differ significantly in terms of sex, age, or level or duration of education. MRI pathological findings (traumatic and nonspecific) were present in nine patients. Traumatic lesions were found in seven patients. Nonspecific white matter lesions were found in five healthy controls. There were significant differences between MTBI patients and controls in terms of subjective symptoms (PCSS) and selected neuropsychological tests. Statistically significant neuropsychological differences were found between MTBI patients with true traumatic lesions and MTBI patients with nonspecific lesions. There is evidence that MTBI patients with true traumatic MRI lesions are neuropsychologically different from MTBI patients with nonspecific MRI lesions or normal brain MRI. These results support the hypothesis that some acute MTBI signs and symptoms have a real organic basis which can be detected by selected new MRI modalities. (orig.)

  16. Temporal filtering of longitudinal brain magnetic resonance images for consistent segmentation

    Directory of Open Access Journals (Sweden)

    Snehashis Roy

    2016-01-01

    Full Text Available Longitudinal analysis of magnetic resonance images of the human brain provides knowledge of brain changes during both normal aging as well as the progression of many diseases. Previous longitudinal segmentation methods have either ignored temporal information or have incorporated temporal consistency constraints within the algorithm. In this work, we assume that some anatomical brain changes can be explained by temporal transitions in image intensities. Once the images are aligned in the same space, the intensities of each scan at the same voxel constitute a temporal (or 4D intensity trend at that voxel. Temporal intensity variations due to noise or other artifacts are corrected by a 4D intensity-based filter that smooths the intensity values where appropriate, while preserving real anatomical changes such as atrophy. Here smoothing refers to removal of sudden changes or discontinuities in intensities. Images processed with the 4D filter can be used as a pre-processing step to any segmentation method. We show that such a longitudinal pre-processing step produces robust and consistent longitudinal segmentation results, even when applying 3D segmentation algorithms. We compare with state-of-the-art 4D segmentation algorithms. Specifically, we experimented on three longitudinal datasets containing 4–12 time-points, and showed that the 4D temporal filter is more robust and has more power in distinguishing between healthy subjects and those with dementia, mild cognitive impairment, as well as different phenotypes of multiple sclerosis.

  17. Impaired cognitive functions in mild traumatic brain injury patients with normal and pathologic magnetic resonance imaging

    International Nuclear Information System (INIS)

    Mild traumatic brain injury (MTBI) is a common neurological (neurotraumatological) diagnosis. As well as different subjective symptoms, many patients develop neuropsychological dysfunction with objective impairment of attention, memory and certain executive functions. Magnetic resonance imaging (MRI) is not routinely used in MTBI patients despite its proven greater sensitivity and specificity in comparison with computed tomography (CT). The patient group consisted of 30 persons with MTBI and the control group consisted of 30 sex- and age-matched healthy volunteers. Both groups underwent neurological examination, neuropsychological testing (including the Postconcussion Symptoms Scale questionnaire, PCSS) and brain MRI (the patient group within 96 h after injury). The analyzed groups did not differ significantly in terms of sex, age, or level or duration of education. MRI pathological findings (traumatic and nonspecific) were present in nine patients. Traumatic lesions were found in seven patients. Nonspecific white matter lesions were found in five healthy controls. There were significant differences between MTBI patients and controls in terms of subjective symptoms (PCSS) and selected neuropsychological tests. Statistically significant neuropsychological differences were found between MTBI patients with true traumatic lesions and MTBI patients with nonspecific lesions. There is evidence that MTBI patients with true traumatic MRI lesions are neuropsychologically different from MTBI patients with nonspecific MRI lesions or normal brain MRI. These results support the hypothesis that some acute MTBI signs and symptoms have a real organic basis which can be detected by selected new MRI modalities. (orig.)

  18. Study of $\\overline{p}$-Nucleus Interaction with a High Resolution Magnetic Spectrometer

    CERN Multimedia

    2002-01-01

    This experiment uses the high resolution, large solid angle and large momentum acceptance magnetic spectrometer SPES~II to study the interaction between @* and complex nuclei in the following experiments: \\\\ \\\\ \\item 1)~~~~A(@*, @*)A. Angular distribution of @* elastically scattered from |1|2C, |4|0Ca and |2|0|8Pb. \\item 2)~~~~A(@*, @*')A*. Excitation energy spectra and some angular distributions of @* inelastically scattered from |1|2C, |4|0Ca and |2|0|8Pb up to an excitation energy of &prop.~100~MeV. \\item 3)~~~~A(@*, p)A^z^-^1 (@*). Excitation energy spectra for knock out reaction on |6Li, |1|2C, |6|3Cu and |2|0|9Bi at several angles. \\end{enumerate}\\\\ \\\\ Any beam momentum between 300 MeV/c and 800 MeV/c will be suitable for this experiment. In order to vary the effect of strong absorption of @* by nuclei, elastic and inelastic scattering will be performed at two or three different @* momenta (depending on the way LEAR will be operated) down to 300~MeV/c.

  19. High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues

    Directory of Open Access Journals (Sweden)

    Boel Lene WT

    2010-03-01

    Full Text Available Abstract Background In biomedical sciences, ex vivo angiography is a practical mean to elucidate vascular structures three-dimensionally with simultaneous estimation of intravascular volume. The objectives of this study were to develop a magnetic resonance (MR method for ex vivo angiography and to compare the findings with computed tomography (CT. To demonstrate the usefulness of this method, examples are provided from four different tissues and species: the human placenta, a rice field eel, a porcine heart and a turtle. Results The optimal solution for ex vivo MR angiography (MRA was a compound containing gelatine (0.05 g/mL, the CT contrast agent barium sulphate (0.43 mol/L and the MR contrast agent gadoteric acid (2.5 mmol/L. It was possible to perform angiography on all specimens. We found that ex vivo MRA could only be performed on fresh tissue because formalin fixation makes the blood vessels permeable to the MR contrast agent. Conclusions Ex vivo MRA provides high-resolution images of fresh tissue and delineates fine structures that we were unable to visualise by CT. We found that MRA provided detailed information similar to or better than conventional CTA in its ability to visualize vessel configuration while avoiding interfering signals from adjacent bones. Interestingly, we found that vascular tissue becomes leaky when formalin-fixed, leading to increased permeability and extravascular leakage of MR contrast agent.

  20. High resolution magnetic resonance imaging of urethral anatomy in continent nulliparous pregnant women

    International Nuclear Information System (INIS)

    Introduction: To quantify the distribution of morphologic appearances of urethral anatomy and measure variables of urethral sphincter anatomy in continent, nulliparous, pregnant women by high resolution magnetic resonance imaging (MRI). Materials and methods: We studied fifteen women during their first pregnancy. We defined and quantified bladder neck and urethral morphology on axial and sagittal MR images from healthy, continent women. Results: The mean (±standard deviation) total transverse urethral diameter, anterior–posterior diameter, unilateral striated sphincter muscle thickness, and striated sphincter length were 15 ± 2 mm (range: 12–19 mm), 15 ± 2 mm (range: 11–20 mm), 2 ± 1 mm (range: 1–4 mm), and 13 ± 3 mm (range: 9–18 mm) respectively. The mean (±standard deviation) total urethral length on sagittal scans was 22 ± 3 mm (range: 17.6–26.4 mm). Discussion: Advances in MR technique combined with anatomical and histological findings will provide an insight to understand how changes in urethral anatomy might affect the continence mechanisms in pregnant and non-pregnant, continent or incontinent individuals.

  1. Magnetization transfer ratio and volumetric analysis of the brain in macrocephalic patients with neurofibromatosis type 1

    Energy Technology Data Exchange (ETDEWEB)

    Margariti, Persefoni N.; Katzioti, Frosso G.; Zikou, Anastasia K.; Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Blekas, Konstantinos [University of Ioannina, Department of Computer Science, Ioannina (Greece); Tzoufi, Meropi [University of Ioannina, Child Health Department, Medical School, Ioannina (Greece)

    2007-02-15

    The purpose of the study was to evaluate brain myelination by measuring the magnetization transfer ratio (MTR) and to measure grey (GMV) and white matter volume (WMV) in macrocephalic children with neurofibromatosis type 1 (NF1). Seven NF1 patients (aged 0.65-16.67 years) and seven age- and gender-matched controls were studied. A three-dimensional (3D) gradient echo sequence with and without magnetization transfer (MT) prepulse was used for MTR assessment. Volume measurements of GM and WM were performed by applying segmentation techniques on T2-weighted turbo spin echo images (T2WI). MTR of unidentified bright objects (UBOs) on T2WI in cerebellar white matter (52.8{+-}3.3), cerebral peduncles (48.5{+-}1.5), hippocampus (52.6{+-}1.1), internal capsule (55.7{+-}0.3), globus pallidus (52.7{+-}3.9), and periventricular white matter (52.6{+-}1.2) was lower than in the corresponding areas of controls (64.6{+-}2.5, 60.8{+-}1.3, 56.4{+-}0.9, 64.7{+-}1.9, 59.2{+-}2.3, 63.6{+-}1.7, respectively; p<0.05). MTR of normal-appearing brain tissue in patients was not significantly different than in controls. Surface area (mm{sup 2}) of the corpus callosum (809.1{+-}62.8), GMV (cm{sup 3}) (850.7{+-}42.9), and white matter volume (WMV) (cm{sup 3}) (785.1{+-}85.2) were greater in patients than in controls (652.5{+-}52.6 mm{sup 2}, 611.2{+-}92.1 cm{sup 3}, 622.5{+-}108.7 cm{sup 3}, respectively; p<0.05). To conclude, macrocephaly in NF1 patients is related to increased GMV and WMV and corpus callosum enlargement. MTR of UBOs is lower than that of normal brain tissue. (orig.)

  2. Fetal magnetic resonance imaging of the brain; Fetale Magnetresonanztomographie des Gehirns

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M. [Johns Hopkins Hospital, Baltimore, MD (United States). Div. of Pediatric Radiology

    2008-03-15

    Fetal magnetic Resonance Imaging (MRI) is a valuable adjunct to ultrasonography (US) in prenatal diagnosis. The high spatial resolution, the large field-of-view, the different contrasts that can be generated and the development of functional MRI-sequences are especially valuable in the diagnosis of complex pathologies of the central nervous system. In addition, fetal MRI does not suffer from obscuring maternal or fetal osseous structures, intestinal gas or maternal obesitas. The ultrafast MRI sequences allow imaging without fetal sedation. Nowadays, fetal MRI is used to confirm, complete or correct US-findings in order to offer the best possible fetal treatment pre- and postnatally. (orig.)

  3. A thin film magnetic field sensor of sub-pT resolution and magnetocardiogram (MCG) measurement at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yabukami, S. [Tohoku-Gakuin University, 1-13-1 Tagajo 985-8537 (Japan)], E-mail: yab@tjcc.tohoku-gakuin.ac.jp; Kato, K.; Ohtomo, Y. [Tohoku-Gakuin University, 1-13-1 Tagajo 985-8537 (Japan); Ozawa, T. [Miyagi National College of Technology, 48 Nodayama, Medeshima-Shiote, Natori 981-1239 (Japan); Arai, K.I. [Research Institute for Electric and Magnetic Materials, 2-1-1 Yagiyama minami, Taihaku-ku, Sendai 982 0807 (Japan); National Institute of Information and Communications Technology, 6-6-3 Minami-Yoshinari, Aoba-ku, Sendai 989 3204 (Japan)

    2009-04-15

    We developed a very sensitive high-frequency carrier-type thin film sensor with a sub-pT resolution using a transmission line. The sensor element consists of Cu conductor with a meander pattern (20 mm in length, 0.8 mm in width, and 18 {mu}m in thickness), a ground plane, and amorphous CoNbZr film (4 {mu}m in thickness). The amplitude modulation technique was employed to enhance the magnetic field resolution for measurement of the high-frequency field (499 kHz), a resolution of 7.10x10{sup -13} T/Hz{sup 1/2} being achieved, when we applied an AC magnetic field at 499 kHz. The phase detection technique was applied for measurement of the low frequency field (around 1 Hz). A small phase change was detected using a dual mixer time difference method. A high phase change of 130 deg./Oe was observed. A magnetic field resolution of 1.35x10{sup -12} T/Hz{sup 1/2} was obtained when a small AC field at 1 Hz was applied. We applied the sensor for magnetocardiogram (MCG) measurement using the phase detection technique. We succeeded in measuring the MCG signal including typical QRS and T waves, and compared the MCG with a simultaneously obtained conventional electrocardiogram (ECG) signal.

  4. Laterality of brain areas associated with arithmetic calculations revealed by functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yun-ting; ZHANG Quan; ZHANG Jing; LI Wei

    2005-01-01

    Background Asymmetry of bilateral cerebral function, i.e. laterality, is an important phenomenon in many brain actions: arithmetic calculation may be one of these phenomena. In this study, first, laterality of brain areas associated with arithmetic calculations was revealed by functional magnetic resonance imaging (fMRI). Second, the relationship among laterality, handedness, and types of arithmetic task was assessed. Third, we postulate possible reasons for laterality.Methods Using a block-designed experiment, twenty-five right-handed and seven left-handed healthy volunteers carried out simple calculations, complex calculations and proximity judgments. T1WI and GRE-EPI fMRI were performed with a GE 1.5T whole body MRI scanner. Statistical parametric mapping (SPM99) was used to process data and localize functional areas. Numbers of activated voxels were recorded to calculate laterality index for evaluating the laterality of functional brain areas.Results For both groups, the activation of functional areas in the frontal lobe showed a tendency towards the nonpredominant hand side, but the functional areas in the inferior parietal lobule had left laterality. During simple and complex calculations, the laterality indices of the prefrontal cortex and premotor area were higher in the right-handed group than that in the left-handed group, whereas the laterality of the inferior parietal lobule had no such significant difference. In both groups, when the difficulty of the task increased, the laterality of the prefrontal cortex, premotor area, and inferior parietal lobule decreased, but the laterality of posterior part of the inferior frontal gyrus increased.Conclusions The laterality of the functional brain areas associated with arithmetic calculations can be detected with fMRI. The laterality of the functional areas was related to handedness and task difficulty.

  5. Magnetic resonance imaging assessment of brain maturation in preterm neonates with punctate white matter lesions

    Energy Technology Data Exchange (ETDEWEB)

    Ramenghi, Luca A.; Fumagalli, Monica; Bassi, Laura; Groppo, Michela; Mosca, Fabio [University of Milan, Neonatal Intensive Care Unit - Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena, IRCCS, Milan (Italy); Righini, Andrea; Parazzini, Cecilia; Bianchini, Elena; Triulzi, Fabio [Ospedale Pediatrico ' ' Buzzi' ' -ICP, Department of Radiology and Neuroradiology, Milan (Italy)

    2007-02-15

    Early white matter (WM) injury affects brain maturation in preterm infants as revealed by diffusion tensor imaging and volumetric magnetic resonance (MR) imaging at term postmenstrual age (PMA). The aim of the study was to assess quantitatively brain maturation in preterm infants with and without milder forms of WM damage (punctate WM lesions, PWML) using conventional MRI. Brain development was quantitatively assessed using a previously validated scoring system (total maturation score, TMS) which utilizes four parameters (progressive myelination and cortical infolding, progressive involution of glial cell migration bands and germinal matrix tissue). PWML were defined as foci of increased signal on T1-weighted images and decreased signal on T2-weighted images with no evidence of cystic degeneration. A group of 22 preterm infants with PWML at term PMA (PWML group) were compared with 22 matched controls with a normal MR appearance. The two groups were comparable concerning gestational age, birth weight and PMA. TMS was significantly lower in the PWML group than in the control group (mean TMS 12.44 {+-} 2.31 vs 14.00 {+-} 1.44; P = 0.011). Myelination (mean 2.76 {+-} 0.42 PWML group vs 3.32 {+-} 0.55 control group, P = 0.003) and cortical folding (3.64 {+-} 0.79 vs 4.09 {+-} 0.43, P = 0.027) appeared to be significantly delayed in babies with PWML. Conventional MRI appears able to quantify morphological changes in brain maturation of preterm babies with PWML; delayed myelination and reduced cortical infolding seem to be the most significant aspects. (orig.)

  6. Magnetic susceptibility of brain iron is associated with childhood spatial IQ.

    Science.gov (United States)

    Carpenter, Kimberly L H; Li, Wei; Wei, Hongjiang; Wu, Bing; Xiao, Xue; Liu, Chunlei; Worley, Gordon; Egger, Helen Link

    2016-05-15

    Iron is an essential micronutrient for healthy brain function and development. Because of the importance of iron in the brain, iron deficiency results in widespread and lasting effects on behavior and cognition. We measured iron in the basal ganglia of young children using a novel MRI method, quantitative susceptibility mapping, and examined the association of brain iron with age and cognitive performance. Participants were a community sample of 39 young children recruited from pediatric primary care who were participating in a 5-year longitudinal study of child brain development and anxiety disorders. The children were ages 7 to 11years old (mean age: 9.5years old) at the time of the quantitative susceptibility mapping scan. The differential abilities scale was administered when the children were 6years old to provide a measure of general intelligence and verbal (receptive and expressive), non-verbal, and spatial performance. Magnetic susceptibility values, which are linearly related to iron concentration in iron-rich areas, were extracted from regions of interest within iron-rich deep gray matter nuclei from the basal ganglia, including the caudate, putamen, substantia nigra, globus pallidus, and thalamus. Controlling for scan age, there was a significant positive association between iron in the basal ganglia and spatial IQ, with this effect being driven by iron in the right caudate We also replicated previous findings of a significant positive association between iron in the bilateral basal ganglia and age. Our finding of a positive association between spatial IQ and mean iron in the basal ganglia, and in the caudate specifically, suggests that iron content in specific regions of the iron-rich deep nuclei of the basal ganglia influences spatial intelligence. This provides a potential neurobiological mechanism linking deficits in spatial abilities reported in children who were severely iron deficient as infants to decreased iron within the caudate. PMID:26899787

  7. Mapping whole-brain activity with cellular resolution by light-sheet microscopy and high-throughput image analysis (Conference Presentation)

    Science.gov (United States)

    Silvestri, Ludovico; Rudinskiy, Nikita; Paciscopi, Marco; Müllenbroich, Marie Caroline; Costantini, Irene; Sacconi, Leonardo; Frasconi, Paolo; Hyman, Bradley T.; Pavone, Francesco S.

    2016-03-01

    Mapping neuronal activity patterns across the whole brain with cellular resolution is a challenging task for state-of-the-art imaging methods. Indeed, despite a number of technological efforts, quantitative cellular-resolution activation maps of the whole brain have not yet been obtained. Many techniques are limited by coarse resolution or by a narrow field of view. High-throughput imaging methods, such as light sheet microscopy, can be used to image large specimens with high resolution and in reasonable times. However, the bottleneck is then moved from image acquisition to image analysis, since many TeraBytes of data have to be processed to extract meaningful information. Here, we present a full experimental pipeline to quantify neuronal activity in the entire mouse brain with cellular resolution, based on a combination of genetics, optics and computer science. We used a transgenic mouse strain (Arc-dVenus mouse) in which neurons which have been active in the last hours before brain fixation are fluorescently labelled. Samples were cleared with CLARITY and imaged with a custom-made confocal light sheet microscope. To perform an automatic localization of fluorescent cells on the large images produced, we used a novel computational approach called semantic deconvolution. The combined approach presented here allows quantifying the amount of Arc-expressing neurons throughout the whole mouse brain. When applied to cohorts of mice subject to different stimuli and/or environmental conditions, this method helps finding correlations in activity between different neuronal populations, opening the possibility to infer a sort of brain-wide 'functional connectivity' with cellular resolution.

  8. Effect of slice thickness on brain magnetic resonance image texture analysis

    Directory of Open Access Journals (Sweden)

    Heinonen Tomi

    2010-10-01

    Full Text Available Abstract Background The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients. Methods We averaged the intensities of three consecutive 1-mm slices to simulate 3-mm slices. Two hundred sixty-four texture parameters were calculated for both the original and the averaged slices. Wilcoxon's signed ranks test was used to find differences between the regions of interest representing white matter and multiple sclerosis plaques. Linear and nonlinear discriminant analyses were applied with several separate training and test sets to determine the actual classification accuracy. Results Only moderate differences in distributions of the texture parameter value for 1-mm and simulated 3-mm-thick slices were found. Our study also showed that white matter areas are well separable from multiple sclerosis plaques even if the slice thickness differs between training and test sets. Conclusions Three-millimeter-thick magnetic resonance image slices acquired with a 1.5 T clinical magnetic resonance scanner seem to be sufficient for texture analysis of multiple sclerosis plaques and white matter tissue.

  9. USE OF PROTON MAGNETIC RESONANCE SPECTROSCOPIC IMAGING DATA IN PLANNING FOCAL RADIATION THERAPIES FOR BRAIN TUMORS

    Directory of Open Access Journals (Sweden)

    Edward E Graves

    2011-05-01

    Full Text Available Advances in radiation therapy for malignant neoplasms have produced techniques such as Gamma Knife radiosurgery, capable of delivering an ablative dose to a specific, irregular volume of tissue. However, efficient use of these techniques requires the identification of a target volume that will produce the best therapeutic response while sparing surrounding normal brain tissue. Accomplishing this task using conventional computed tomography (CT and contrast-enhanced magnetic resonance imaging (MRI techniques has proven difficult because of the difficulties in identifying the effective tumor margin. Magnetic resonance spectroscopic imaging (MRSI has been shown to offer a clinically-feasible metabolic assessment of the presence and extent of neoplasm that can complement conventional anatomic imaging. This paper reviews current Gamma Knife protocols and MRSI acquisition, reconstruction, and interpretation techniques, and discusses the motivation for including magnetic resonance spectroscopy findings while planning focal radiation therapies. A treatment selection and planning strategy incorporating MRSI is then proposed, which can be used in the future to assess the efficacy of spectroscopy-based therapy planning.

  10. Magnetization transfer studies of the fast and slow tissue water diffusion components in the human brain.

    Science.gov (United States)

    Mulkern, Robert V; Vajapeyam, Sridhar; Haker, Steven J; Maier, Stephan E

    2005-05-01

    Magnetization transfer (MT) properties of the fast and slow diffusion components recently observed in the human brain were assessed experimentally. One set of experiments, performed at 1.5 T in healthy volunteers, was designed to determine whether the amplitudes of fast and slow diffusion components, differentiated on the basis of biexponential fits to signal decays over a wide range of b-factors, demonstrated a different or similar magnetization transfer ratio (MTR). Another set of experiments, performed at 3 T in healthy volunteers, was designed to determine whether MTRs differed when measured from high signal-to-noise images acquired with b-factor weightings of 350 vs 3500 s/mm2. The 3 T studies included measurements of MTR as a function of off-resonance frequency for the MT pulse at both low and high b-factors. The primary conclusion drawn from all the studies is that there appears to be no significant difference between the magnetization transfer properties of the fast and slow tissue water diffusion components. The conclusions do not lend support to a direct interpretation of the 'components' of the biexponential diffusion decay in terms of the 'compartments' associated with intra- and extracellular water. PMID:15578729

  11. Functional magnetic resonance imaging can be used to explore tactile and nociceptive processing in the infant brain

    OpenAIRE

    Williams, G.; Fabrizi, L.; Meek, J; Jackson, D; Tracey, I; Robertson, N; Slater, R.; Fitzgerald, M.

    2014-01-01

    Aim Despite the importance of neonatal skin stimulation, little is known about activation of the newborn human infant brain by sensory stimulation of the skin. We carried out functional magnetic resonance imaging (fMRI) to assess the feasibility of measuring brain activation to a range of mechanical stimuli applied to the skin of neonatal infants. Methods We studied 19 term infants with a mean age of 13 days. Brain activation was measured in response to brushing, von Frey hair (vFh) punctate ...

  12. Investigating the impact of blood pressure increase to the brain using high resolution serial histology and image processing

    Science.gov (United States)

    Lesage, F.; Castonguay, A.; Tardif, P. L.; Lefebvre, J.; Li, B.

    2015-09-01

    A combined serial OCT/confocal scanner was designed to image large sections of biological tissues at microscopic resolution. Serial imaging of organs embedded in agarose blocks is performed by cutting through tissue using a vibratome which sequentially cuts slices in order to reveal new tissue to image, overcoming limited light penetration encountered in microscopy. Two linear stages allow moving the tissue with respect to the microscope objective, acquiring a 2D grid of volumes (1x1x0.3 mm) with OCT and a 2D grid of images (1x1mm) with the confocal arm. This process is repeated automatically, until the entire sample is imaged. Raw data is then post-processed to re-stitch each individual acquisition and obtain a reconstructed volume of the imaged tissue. This design is being used to investigate correlations between white matter and microvasculature changes with aging and with increase in pulse pressure following transaortic constriction in mice. The dual imaging capability of the system allowed to reveal different contrast information: OCT imaging reveals changes in refractive indices giving contrast between white and grey matter in the mouse brain, while transcardial perfusion of FITC or pre-sacrifice injection of Evans Blue shows microsvasculature properties in the brain with confocal imaging.

  13. Enhancing lexical ambiguity resolution by brain polarization of the right posterior superior temporal sulcus.

    Science.gov (United States)

    Peretz, Yael; Lavidor, Michal

    2013-04-01

    Previous studies have reported a hemispheric asymmetry in processing dominant (e.g., paper) and subordinate (e.g., farmer) associations of ambiguous words (pen). Here we applied sham and anodal Transcranial Direct Current Stimulation (tDCS) over Wernicke's area and its right homologue to test whether we can modulate the selective hemispheric expertise in processing lexical ambiguity. Ambiguous prime words were presented followed by target words that could be associated to the dominant or subordinate meaning of the prime in a semantic relatedness task. Anodal stimulation of the right Wernicke's area significantly decreased response time (RTs) to subordinate but not dominant associations compared to sham stimulation. There was also a complementary trend of faster responses to dominant associations following anodal stimulation of Wernicke's area. The results support brain asymmetry in processing lexical ambiguity and show that tDCS can enhance complex language processing even in a sample of highly literate individuals. PMID:22513342

  14. Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation

    Science.gov (United States)

    Andrews, Russell J.

    2003-01-01

    Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.

  15. Three-Dimensional Electroencephalographic Changes on Low-Resolution Brain Electromagnetic Tomography (LORETA) During the Sleep Onset Period.

    Science.gov (United States)

    Park, Doo-Heum; Ha, Jee Hyun; Ryu, Seung-Ho; Yu, Jaehak; Shin, Chul-Jin

    2015-10-01

    Electroencephalographic (EEG) patterns during sleep are markedly different from those measured during the waking state, but the process of falling asleep is not fully understood in terms of biochemical and neurophysiological aspects. We sought to investigate EEG changes that occur during the transitional period from wakefulness to sleep in a 3-dimensional manner to gain a better understanding of the physiological meaning of sleep for the brain. We examined EEG 3-dimensionally using LORETA (low-resolution electromagnetic tomography), to localize the brain region associated with changes that occur during the sleep onset period (SOP). Thirty-channel EEG was recorded in 61 healthy subjects. EEG power spectra and intracortical standardized LORETA were compared between 4 types of 30-second states, including the wakeful stage, transition stage, early sleep stage 1, and late sleep stage 1. Sleep onset began with increased delta and theta power and decreased alpha-1 power in the occipital lobe, and increased theta power in the parietal lobe. Thereafter, global reductions of alpha-1 and alpha-2 powers and greater increases of theta power in the occipito-parietal lobe occurred. As sleep became deeper in sleep stage 1, beta-2 and beta-3, powers decreased mainly in the frontal lobe and some regions of the parieto-temporo-limbic area. These findings suggest that sleep onset includes at least 3 steps in a sequential manner, which include an increase in theta waves in the posterior region of the brain, a global decrease in alpha waves, and a decrease in beta waves in the fronto-central area. PMID:25150221

  16. Direct mapping of 19F in 19FDG-6P in brain tissue at subcellular resolution using soft X-ray fluorescence

    OpenAIRE

    Poitry-yamate, Carole; Gianoncelli, A; Kourousias, G.; Kaulich, B; Lepore, Mario; Gruetter, Rolf; M. Kiskinova

    2013-01-01

    Low energy x-ray fluorescence (LEXRF) detection was optimized for imaging cerebral glucose metabolism by mapping the fluorine LEXRF signal of 19 F in 19 FDG, trapped as intracellular 19 F-deoxyglucose-6-phosphate ( 19 FDG-6P) at 1μm spatial resolution from 3μm thick brain slices. 19 FDG metabolism was evaluated in brain structures closely resembling the general cerebral cytoarchitecture following formalin fixation of brain slices and their inclusion in an epon matrix. 2-dimensional distribu...

  17. In vivo imaging of brain dopaminergic neurotransmission system in small animals with high-resolution single photon emission computed tomography

    International Nuclear Information System (INIS)

    High-resolution single photon emission computed tomography (SPECT) provides a unique capability to image the biodistribution of radiolabeled molecules in small laboratory animals. Thus, we applied the high-resolution SPECT to in vivo imaging of the brain dopaminergic neurotransmission system in common marmosets using two radiolabeled ligands, [123I]2β-carbomethoxy-3β-(4-iodophenyl)tropane (β-CIT) as a dopamine transporter(DAT) ligand and [123I]iodobenzamide (IBZM) as a dopamine D2 receptor (D2R) ligand. Specific images of the striatum, a region with a high density of dopaminergic synapses, were obtained at 240 min and 60 min after injection of [123I]β-CIT and [123I]IBZM, respectively. Furthermore, a significantly low accumulation of [123I]β-CIT in the striatum was observed in MPTP-treated animals compared with results for a control group, and a similar accumulation in the control group was observed with the pretreatment of deprenyl in the MPTP-treated animals. However, the striatal accumulation of [123I]IBZM showed no changes among the control, MPTP-treated, and deprenyl-MPTP-treated groups. These SPECT imaging results agreed well with those of DA concentration and motor behavior. Since MPTP destroys nigrostriatal dopamine nerves and produces irreversible neurodegeneration associated with Parkinsonian syndrome, SPECDT imaging data in this study demonstrated that deprenyl shows its neuroprotective effect on Parkinsonism by protecting against the destruction of presynaptic dopamine neutrons. (author)

  18. A combined solenoid-surface RF coil for high-resolution whole-brain rat imaging on a 3.0 Tesla clinical MR scanner.

    Science.gov (United States)

    Underhill, Hunter R; Yuan, Chun; Hayes, Cecil E

    2010-09-01

    Rat brain models effectively simulate a multitude of human neurological disorders. Improvements in coil design have facilitated the wider utilization of rat brain models by enabling the utilization of clinical MR scanners for image acquisition. In this study, a novel coil design, subsequently referred to as the rat brain coil, is described that exploits and combines the strengths of both solenoids and surface coils into a simple, multichannel, receive-only coil dedicated to whole-brain rat imaging on a 3.0 T clinical MR scanner. Compared with a multiturn solenoid mouse body coil, a 3-cm surface coil, a modified Helmholtz coil, and a phased-array surface coil, the rat brain coil improved signal-to-noise ratio by approximately 72, 61, 78, and 242%, respectively. Effects of the rat brain coil on amplitudes of static field and radiofrequency field uniformity were similar to each of the other coils. In vivo, whole-brain images of an adult male rat were acquired with a T(2)-weighted spin-echo sequence using an isotropic acquisition resolution of 0.25 x 0.25 x 0.25 mm(3) in 60.6 min. Multiplanar images of the in vivo rat brain with identification of anatomic structures are presented. Improvement in signal-to-noise ratio afforded by the rat brain coil may broaden experiments that utilize clinical MR scanners for in vivo image acquisition. PMID:20535812

  19. Efficacy of High Resolution Magnetic Resonance Imaging in Preoperative Local Staging of Rectal Cancer

    Directory of Open Access Journals (Sweden)

    Aysun Uçar

    2013-08-01

    Full Text Available Objective: To assess the efficacy of high-resolution magnetic resonance imaging (HRMRI for preoperative local staging in patients with rectal cancer who did not receive preoperative radiochemotherapy. Methods: In this retrospective study, 30 patients with biopsy proved primary rectal cancer were evaluated by HRMRI. Two observers independently scored the tumour and lymph node stages, and circumferential resection margin (CRM involvement. The sensitivity, specificity, the negative predictive value and the positive predictive value of HRMRI findings were calculated within the 95% confidence interval. The area under the curve was measured for each result. Agreement between two observers was assessed by means of the Kappa test. Results: In T staging the accuracy rate of HRMRI was 47-67%, overstaging was 10-21%, and understaging was 13-43%. In the prediction of extramural invasion with HRMRI, the sensitivity was 79-89%, the specificity was 72-100%, the PPV was 85-100%, the NPV was 73-86%, and the area under the curve was 0.81-0.89. In the prediction of lymph node metastasis, the sensitivity was 58-58%, the specificity was 50-55%, the PPV was 43-46%, and the NPV was 64-66%. The area under the curve was 0.54-0.57. When the cut off value was selected as 1 mm, the sensitivity of HRMRI was 38-42%, the specificity was 73-82%, the PPV was 33-42%, and NPV was 79-81% in the prediction of the CRM involvement. The correlation between the two observers was moderate for tumour staging, substantial for lymph node staging and predicting of CRM involvement. Conclusion: Preoperative HRMRI provides good predictive data for extramural invasion but poor prediction of lymph node status and CRM involvement.

  20. First MMS Observations of High Time Resolution 3D Electric and Magnetic fields at the Dayside Magnetopause.

    Science.gov (United States)

    Torbert, R. B.; Burch, J. L.; Russell, C. T.; Magnes, W.; Ergun, R. E.; Lindqvist, P. A.; Le Contel, O.; Vaith, H.; Macri, J.; Myers, S.; Rau, D.; Needell, J.; King, B.; Granoff, M.; Chutter, M.; Dors, I.; Argall, M. R.; Shuster, J. R.; Olsson, G.; Marklund, G. T.; Khotyaintsev, Y. V.; Eriksson, A. I.; Kletzing, C.; Bounds, S. R.; Anderson, B. J.; Baumjohann, W.; Steller, M.; Bromund, K. R.; Le, G.; Nakamura, R.; Strangeway, R. J.; Leinweber, H. K.; Tucker, S.; Westfall, J.; Fischer, D.; Plaschke, F.; Pollock, C. J.; Giles, B. L.; Moore, T. E.; Mauk, B.; Fuselier, S. A.

    2015-12-01

    The electrodynamics at the magnetopause is key to our understanding of ion and electron acceleration within reconnection regions. The Magnetospheric Multiscale (MMS) fleet of four spacecraft was launched into its Phase-1 equatorial orbit of 12 Re apogee specifically to investigate these regions at the Earth's magnetopause. In addition to a comprehensive suite of particle measurements, MMS makes very high time resolution 3D electric and magnetic field measurements of high accuracy using flux-gate, search coil, 3-axis double probe, and electron drift sensors. In September 2015, the MMS fleet will begin to encounter the dusk-side magnetopause in its initial configuration of approximately 160 km separation, allowing investigation of the spatial and temporal characteristics of important electrodynamics during reconnection. Using these field and particle measurements, we present first observations of 3D magnetic and electric fields (including their parallel component), and inferred current sheets, during active magnetopause crossings using the highest time resolution data available on MMS.

  1. Quantification of dopamine transporters in the mouse brain using ultra-high resolution single-photon emission tomography

    International Nuclear Information System (INIS)

    Functional imaging of small animals, such as mice and rats, using ultra-high resolution positron emission tomography (PET) and single-photon emission tomography (SPET), is becoming a valuable tool for studying animal models of human disease. While several studies have shown the utility of PET imaging in small animals, few have used SPET in real research applications. In this study we aimed to demonstrate the feasibility of using ultra-high resolution SPET in quantitative studies of dopamine transporters (DAT) in the mouse brain. Four healthy ICR male mice were injected with (mean±SD) 704±154 MBq [99mTc]TRODAT-1, and scanned using an ultra-high resolution SPET system equipped with pinhole collimators (spatial resolution 0.83 mm at 3 cm radius of rotation). Each mouse had two studies, to provide an indication of test-retest reliability. Reference tissue kinetic modeling analysis of the time-activity data in the striatum and cerebellum was used to quantitate the availability of DAT. A simple equilibrium ratio of striatum to cerebellum provided another measure of DAT binding. The SPET imaging results were compared against ex vivo biodistribution data from the striatum and cerebellum. The mean distribution volume ratio (DVR) from the reference tissue kinetic model was 2.17±0.34, with a test-retest reliability of 2.63%±1.67%. The ratio technique gave similar results (DVR=2.03±0.38, test-retest reliability=6.64%±3.86%), and the ex vivo analysis gave DVR=2.32±0.20. Correlations between the kinetic model and the ratio technique (R2=0.86, P2=0.92, P=0.04) were both excellent. This study demonstrated clearly that ultra-high resolution SPET of small animals is capable of accurate, repeatable, and quantitative measures of DAT binding, and should open up the possibility of further studies of cerebral binding sites in mice using pinhole SPET. (orig.)

  2. Annotation: What Electrical Brain Activity Tells Us about Brain Function that Other Techniques Cannot Tell Us--A Child Psychiatric Perspective

    Science.gov (United States)

    Banaschewski, Tobias; Brandeis, Daniel

    2007-01-01

    Background: Monitoring brain processes in real time requires genuine subsecond resolution to follow the typical timing and frequency of neural events. Non-invasive recordings of electric (EEG/ERP) and magnetic (MEG) fields provide this time resolution. They directly measure neural activations associated with a wide variety of brain states and…

  3. Analyzing the effects of a single episode of neonatal maternal deprivation on metabolite profiles in rat brain: a proton nuclear magnetic resonance spectroscopy study.

    Science.gov (United States)

    Llorente, R; Villa, P; Marco, E M; Viveros, M P

    2012-01-10

    Animal models have greatly contributed to the understanding of neuropsychiatric disorders and have provided extensive evidence for the "neurodevelopmental hypothesis." In this regard, a single and prolonged episode (24 h) of early maternal deprivation early in life, on postnatal day 9, has been proposed as an animal model for the investigation of certain neuropsychiatric disorders, including schizophrenia. Since metabolic changes in hippocampus (HIP) and prefrontal cortex (PFC) have been described among schizophrenic patients by using ex vivo high-resolution magic angle spinning (HR-MAS) proton ((1)H) nuclear magnetic resonance spectroscopy, in the present study we aimed to investigate the effects of maternal deprivation (MD) on the metabolite profiles of the developing brain by using the HR-MAS technique. MD significantly altered the hippocampal and cortical metabolic profile of neonatal rats (PND 13) in a sex-dependent manner. Glutamine and glutamate (Glx) and taurine of male and female rat pups were altered in both brain areas analyzed. Differences in hippocampal phosphorylethanolamine have also been found as a function of the MD protocol. In addition, MD induced some other region- and sex-dependent effects, including changes in N-acetyl aspartate and total choline signals in the hippocampi of male pups. Present findings indicate a different brain metabolic profile in our animal model of early life stress suggesting its potential utility in the implementation of translational neuropsychiatric research.

  4. Proton magnetic resonance spectroscopy of normal human brain and glioma:a quantitive in vivo study

    Institute of Scientific and Technical Information of China (English)

    TONG Zhi-yong; YAMAKI Toshiaki; WANG Yun-jie

    2005-01-01

    Background In vivo proton magnetic resonance spectroscopy (MRS) provides a noninvasive method of examining a wide variety of cerebral metabolites in both healthy subjects and patients with various brain diseases.Absolute metabolite concentrations have been determined using external and internal standards with known concentrations.When an external standard is placed beside the head, variations in signal amplitudes due to B1 field inhomogeneity and static field inhomogeneity may occur.Hence an internal standard is preferable.The purpose of this study was to quantitatively analyze the metabolite concentrations in normal adult brains and gliomas by in vivo proton MRS using the fully relaxed water signal as an internal standard.Methods Between January 1998 and October 2001, 28 healthy volunteers and 16 patients with gliomas were examined by in vivo proton MRS.Single-voxel spectra were acquired using the point-resolved spectroscopic pulse sequence with a 1.5 T scanner (TR/TE/Ave=3000 ms/30 ms/64).Results The calculated concentrations of N-acetyl-asparatate (NAA), creatine (Cre), choline (Cho), and water (H2O) in the normal hemispheric white matter were (23.59±2.62) mmol/L, (13.06±1.8) mmol/L, (4.28±0.8) mmol/L, and (47 280.96±5414.85) mmol/L, respectively.The metabolite concentrations were not necessarily uniform in different parts of the brain.The concentrations of NAA and Cre decreased in all gliomas (P<0.001).The ratios of NAA/Cho and NAA/H2O showed a significant difference between the normal brain and gliomas, and also between the high and low grades (P<0.001).Conclusions Quantitative analysis of in vivo proton MR spectra using the fully relaxed water signal as an internal standard is useful.The concentrations of NAA and the ratios of NAA/H2O and NAA/Cho conduce to discriminating between the glioma and normal brain, and also between the low-grade glioma and high-grade glioma.

  5. Neuropsychological correlates of brain atrophy in Huntington's disease: a magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Magnetic resonance imaging and a comprehensive cognitive evaluation were carried out in a series of 29 patients with mild to moderate Huntington's disease (HD). A factor analysis of the neuropsychological test scores provided three factors: A memory/speed-of-processing factor, a 'frontal' factor, and a response inhibition factor. The memory/speed factor correlated significantly with measures of caudate atrophy, frontal atrophy, and atrophy of the left (but not the right) sylvian cistern. There were no significant correlations between the 'frontal' or response inhibition factors and measures of cortical or subcortical brain atrophy. Our findings confirm that subcortical atrophy is significantly correlated with specific cognitive deficits in HD, and demonstrate that cortical atrophy also has important association with the cognitive deficits of patients with HD. (orig.)

  6. Neuropsychological correlates of brain atrophy in Huntington's disease: a magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Starkstein, S.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States). Dept. of Psychiatry Inst. of Neurological Investigation ' Dr. Raul Carrea' , Buenos Aires (Argentina)); Brandt, J.; Bylsma, F.; Peyser, C.; Folstein, M.; Folstein, S.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States). Dept. of Psychiatry)

    1992-11-01

    Magnetic resonance imaging and a comprehensive cognitive evaluation were carried out in a series of 29 patients with mild to moderate Huntington's disease (HD). A factor analysis of the neuropsychological test scores provided three factors: A memory/speed-of-processing factor, a 'frontal' factor, and a response inhibition factor. The memory/speed factor correlated significantly with measures of caudate atrophy, frontal atrophy, and atrophy of the left (but not the right) sylvian cistern. There were no significant correlations between the 'frontal' or response inhibition factors and measures of cortical or subcortical brain atrophy. Our findings confirm that subcortical atrophy is significantly correlated with specific cognitive deficits in HD, and demonstrate that cortical atrophy also has important association with the cognitive deficits of patients with HD. (orig.).

  7. Subacute sclerosing panencephalitis with bilateral inferior collicular hyperintensity on magnetic resonance imaging brain

    Directory of Open Access Journals (Sweden)

    Maya Thomas

    2012-01-01

    Full Text Available Subacute sclerosing panencephalitis (SSPE is chronic encephalitis occurring after infection with measles virus. An 8-year-old boy presented with progressive behavioral changes, cognitive decline and myoclonic jerks, progressing to a bed bound state over 2 months. Magnetic resonance imaging (MRI brain showed T2-weighted hyperintensities in the subcortical areas of the left occipital lobe and brachium of the inferior colliculus on both sides. EEG showed bilateral, synchronous periodic discharges. Serum/cerebrospinal fluid measles IgG titer was significantly positive. The overall features were suggestive of SSPE. MRI finding of bilateral inferior colliculus changes on MRI without significant involvement of other commonly involved areas suggests an uncommon/rare imaging pattern of SSPE.

  8. A water-fat separation imaging method for the brain on low field magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Hong-jun Tian; Si-ping Chen; Tian-fu Wang; Xian-fen Diao; Chong-xun Zheng

    2009-01-01

    Water-fat separation is a particularly important problem for magnetic resonance imaging. Although many methods have been proposed, the reliability is still challenging. In this work, we have presented a method based on the combination of the branch-cut method and multigrid algorithm to get a more robust performance of water-fat separation. First, the branch-cut method is applied to identify residues, which violates the requirement that the interacting phase gradient around a closed path be zero. Residues and branches are marked to be zeros and filled to the weighting factor array. Then, the unwrapped phase array can be given by the multigrid algorithm. Finally, the Dixon method for water-fat separation is applied to the unwrapped phase array. Experiments for brain scanning on the 0.3T low field MRI system demonstrate the successful application of the proposed method.

  9. Measurements of the magnetic fields produced by the human heart, brain, and lungs

    International Nuclear Information System (INIS)

    Magnetic fields produced by organs of the human body are being measured in a shielded room, using both a SQUID magnetometer and second-derivative gradiometer. Measurements of the field around the human body can yield new information not obtainable with surface electrodes about organs which generate current and about organs which contain foreign, ferromagnetic particles. Magnetocardiograms of normal and abnormal heart subjects are being analyzed and visually displayed in order to assess their information content. Magnetoencephalograms recorded from normal and abnormal brain subjects are also under analysis. Measurements were made of magnetite dust in the lung, with two potential medical applications: (1) the use of pure magnetite dust as a deliberately inhaled tracer (harmless) for pulmonary diagnosis; and (2) the assessment of the amount of asbestos accumulated in the lungs of heavily-exposed workers, since most asbestos (harmful) occurs with adhered magnetite

  10. Magnetic resonance imaging for radiotherapy planning of brain cancer patients using immobilization and surface coils

    International Nuclear Information System (INIS)

    This study investigated the compatibility of a head and neck immobilization device with magnetic resonance imaging (MRI). The immobilization device is used to position a patient in the same way as when receiving a computed tomography (CT) scan for radiotherapy planning and radiation treatment. The advantage of using immobilization in MR is improved accuracy in CT/MR image registration enabling greater confidence in the delineation of structures. The main practical difficulty in using an immobilization device in MRI is that physical constraints make their use incompatible with head imaging coils. Within this paper we describe a method for MR imaging of the brain which allows the use of head and neck immobilization devices. By a series of image quality tests we obtained the same or better image quality as a multi-channel head coil.

  11. The impact of data preprocessing in traumatic brain injury detection using functional magnetic resonance imaging.

    Science.gov (United States)

    Vergara, Victor M; Damaraju, Eswar; Mayer, Andrew B; Miller, Robyn; Cetin, Mustafa S; Calhoun, Vince

    2015-01-01

    Traumatic brain injury (TBI) can adversely affect a person's thinking, memory, personality and behavior. For this reason new and better biomarkers are being investigated. Resting state functional network connectivity (rsFNC) derived from functional magnetic resonance (fMRI) imaging is emerging as a possible biomarker. One of the main concerns with this technique is the appropriateness of methods used to correct for subject movement. In this work we used 50 mild TBI patients and matched healthy controls to explore the outcomes obtained from different fMRI data preprocessing. Results suggest that correction for motion variance before spatial smoothing is the best alternative. Following this preprocessing option a significant group difference was found between cerebellum and supplementary motor area/paracentral lobule. In this case the mTBI group exhibits an increase in rsFNC.

  12. Association of Metabolic Dysregulation With Volumetric Brain Magnetic Resonance Imaging and Cognitive Markers of Subclinical Brain Aging in Middle-Aged Adults

    OpenAIRE

    Beiser, Alexa S; Au, Rhoda; Himali, Jayandra J.; Debette, Stephanie; DeCarli, Charles; Vasan, Ramachandran S.; Wolf, Philip A.; Seshadri, Sudha; Tan, Zaldy S.; Fox, Caroline

    2011-01-01

    Objective: Diabetic and prediabtic states, including insulin resistance, fasting hyperglycemia, and hyperinsulinemia, are associated with metabolic dysregulation. These components have been individually linked to increased risks of cognitive decline and Alzheimer’s disease. We aimed to comprehensively relate all of the components of metabolic dysregulation to cognitive function and brain magnetic resonance imaging (MRI) in middle-aged adults. Research Design and Methods: Framingham Offspring ...

  13. Improved Bathymetry Resolution in the Ross Sea from Aerogravity and Magnetics: Examples from Operation IceBridge.

    Science.gov (United States)

    Tinto, K. J.; Cochran, J. R.; Bell, R. E.; Charles, K.; Burton, B.

    2014-12-01

    The Ross Ice Shelf, located in the embayment between East and West Antarctica, is one of the largest underexplored patches of ocean on the planet. Sediment cores show that the Ross Ice Shelf can disintegrate during some interglacial periods. The conditions required for sudden collapse are not well constrained. A key to understanding the dynamics and long-term stability of the Ross Ice Shelf system is having high-resolution constraints on its boundary conditions, including sea floor bathymetry. The sea floor under the Ross Ice Shelf has developed in response to both the tectonic development of the West Antarctic Rift and the glacial signature of the waxing and waning Antarctic Ice Sheets. A mixture of fabrics and orientations in its bathymetry reflect this complex development. However, present oceanographic models of water circulation under the ice are based on low-resolution bathymetric maps drawn from stations spaced 55 km apart obtained during the RIGGS project in the 1970s. In contrast, most of the bathymetry of the world's oceans has been mapped to approximately 15 km resolution from satellite altimetry and much higher resolution from acoustic surveys. Improvement of Ross Ice Shelf bathymetry can be achieved from combined analysis and inversion of gravity and magnetic data acquired from airborne surveys over the Ross Ice Shelf. Survey lines flown in 2013 by Operation IceBridge, with the Sander Geophysics Ltd AIRGrav system over the central and northern Ross Embayment provide a tenfold increase, to 5 km, of the along track resolution of bathymetry. Newly resolved bathymetric highs and lows have amplitudes of up to 200 km. Combining the gravity and magnetic surveys also reveals the differing geology across the embayment. Results from these surveys, including comparison with ship-based bathymetry data from the Ross Sea, demonstrate the value of gravity and magnetic surveys for mapping the bathymetry of the Ross Ice Shelf and the need for more comprehensive

  14. Love-related changes in the brain: A resting-state functional magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Hongwen eSong

    2015-02-01

    Full Text Available Romantic love is a motivational state associated with a desire to enter or maintain a close relationship with a specific other person. Studies with functional magnetic resonance imaging (fMRI have found activation increases in brain regions involved in processing of reward, emotion, motivation when romantic lovers view photographs of their partners. However, not much is known on whether romantic love affects the brain’s functional architecture during rest. In the present study, resting state functional magnetic resonance imaging (rsfMRI data was collected to compare the regional homogeneity (ReHo and functional connectivity (FC across a lover group (LG, N=34, currently intensely in love, ended-love group (ELG, N=34, romantic relationship ended recently, and single group (SG, N=32, never fallen in love.The results showed that:1 ReHo of the left dorsal anterior cingulate cortex (dACC was significantly increased in the LG (in comparison to the ELG and the SG; 2 ReHo of the left dACC was positively correlated with length of time in love in the LG, and negatively correlated with the lovelorn duration since breakup in the ELG; 3 functional connectivity (FC within the reward, motivation, and emotion network (dACC, insula, caudate, amygdala and nucleus accumbens and the social cognition network (temporo-parietal junction (TPJ, posterior cingulate cortex (PCC, medial prefrontal cortex (MPFC, inferior parietal, precuneus and temporal lobe was significantly increased in the LG (in comparison to the ELG and SG; 4 in most regions within both networks FC was positively correlated with the love duration in the LG but negatively correlated with the lovelorn duration in the ELG. This study provides first empirical evidence of love-related alterations of brain functional architecture. The results shed light on the underlying neural mechanisms of romantic love, and demonstrate the possibility of applying a resting state approach for investigating romantic love.

  15. Brain activation and inhibition after acupuncture at Taichong and Taixi: resting-state functional magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Shao-qun Zhang

    2015-01-01

    Full Text Available Acupuncture can induce changes in the brain. However, the majority of studies to date have focused on a single acupoint at a time. In the present study, we observed activity changes in the brains of healthy volunteers before and after acupuncture at Taichong (LR3 and Taixi (KI3 using resting-state functional magnetic resonance imaging. Fifteen healthy volunteers underwent resting-state functional magnetic resonance imaging of the brain 15 minutes before acupuncture, then received acupuncture at Taichong and Taixi using the nail-pressing needle insertion method, after which the needle was retained in place for 30 minutes. Fifteen minutes after withdrawal of the needle, the volunteers underwent a further session of resting-state functional magnetic resonance imaging, which revealed that the amplitude of low-frequency fluctuation, a measure of spontaneous neuronal activity, increased mainly in the cerebral occipital lobe and middle occipital gyrus (Brodmann area 18/19, inferior occipital gyrus (Brodmann area 18 and cuneus (Brodmann area 18, but decreased mainly in the gyrus rectus of the frontal lobe (Brodmann area 11, inferior frontal gyrus (Brodmann area 44 and the center of the posterior lobe of the cerebellum. The present findings indicate that acupuncture at Taichong and Taixi specifically promote blood flow and activation in the brain areas related to vision, emotion and cognition, and inhibit brain areas related to emotion, attention, phonological and semantic processing, and memory.

  16. Brain activation and inhibition after acupuncture at Taichong and Taixi: resting-state functional magnetic resonance imaging.

    Science.gov (United States)

    Zhang, Shao-Qun; Wang, Yan-Jie; Zhang, Ji-Ping; Chen, Jun-Qi; Wu, Chun-Xiao; Li, Zhi-Peng; Chen, Jia-Rong; Ouyang, Huai-Liang; Huang, Yong; Tang, Chun-Zhi

    2015-02-01

    Acupuncture can induce changes in the brain. However, the majority of studies to date have focused on a single acupoint at a time. In the present study, we observed activity changes in the brains of healthy volunteers before and after acupuncture at Taichong (LR3) and Taixi (KI3) using resting-state functional magnetic resonance imaging. Fifteen healthy volunteers underwent resting-state functional magnetic resonance imaging of the brain 15 minutes before acupuncture, then received acupuncture at Taichong and Taixi using the nail-pressing needle insertion method, after which the needle was retained in place for 30 minutes. Fifteen minutes after withdrawal of the needle, the volunteers underwent a further session of resting-state functional magnetic resonance imaging, which revealed that the amplitude of low-frequency fluctuation, a measure of spontaneous neuronal activity, increased mainly in the cerebral occipital lobe and middle occipital gyrus (Brodmann area 18/19), inferior occipital gyrus (Brodmann area 18) and cuneus (Brodmann area 18), but decreased mainly in the gyrus rectus of the frontal lobe (Brodmann area 11), inferior frontal gyrus (Brodmann area 44) and the center of the posterior lobe of the cerebellum. The present findings indicate that acupuncture at Taichong and Taixi specifically promote blood flow and activation in the brain areas related to vision, emotion and cognition, and inhibit brain areas related to emotion, attention, phonological and semantic processing, and memory. PMID:25883630

  17. Brain activation and inhibition after acupuncture at Taichong andTaixi:resting-state functional magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Shao-qun Zhang; Chun-zhi Tang; Yan-jie Wang; Ji-ping Zhang; Jun-qi Chen; Chun-xiao Wu; Zhi-peng Li; Jia-rong Chen; Huai-liang Ouyang; Yong Huang

    2015-01-01

    Acupuncture can induce changes in the brain. However, the majority of studies to date have focused on a single acupoint at a time. In the present study, we observed activity changes in the brains of healthy volunteers before and after acupuncture atTaichong (LR3) andTaixi (KI3) using resting-state functional magnetic resonance imaging. Fifteen healthy volunteers underwent resting-state functional magnetic resonance imaging of the brain 15 minutes before acupuncture, then received acupuncture atTaichong andTaixi using the nail-pressing needle insertion method, after which the needle was retained in place for 30 minutes. Fifteen minutes after withdrawal of the needle, the volunteers underwent a further session of resting-state functional magnetic res-onance imaging, which revealed that the amplitude of low-frequency lfuctuation, a measure of spontaneous neuronal activity, increased mainly in the cerebral occipital lobe and middle occipital gyrus (Brodmann area 18/19), inferior occipital gyrus (Brodmann area 18) and cuneus (Brodmann area 18), but decreased mainly in the gyrus rectus of the frontal lobe (Brodmann area 11), inferi-or frontal gyrus (Brodmann area 44) and the center of the posterior lobe of the cerebellum. The present ifndings indicate that acupuncture atTaichong andTaixi speciifcally promote blood lfow and activation in the brain areas related to vision, emotion and cognition, and inhibit brain areas related to emotion, attention, phonological and semantic processing, and memory.

  18. Dosimetric and geometric evaluation of an open low-field magnetic resonance simulator for radiotherapy treatment planning of brain tumours

    DEFF Research Database (Denmark)

    Kristensen, B.H.; Laursen, F.J.; Logager, V.;

    2008-01-01

    Background and purpose: Magnetic resonance (MR) imaging is superior to computed tomography (CT) in radiotherapy of brain tumours. In this study an open low-field MR-simulator is evaluated in order to eliminate the cost of and time spent on additional CT scanning. Materials and methods: Eleven...

  19. Comparison between neuroimaging classifications and histopathological diagnoses using an international multicenter brain tumor magnetic resonance imaging database.

    NARCIS (Netherlands)

    Julia-Sape, M.; Acosta, D.M.; Majos, C.; Moreno-Torres, A.; Wesseling, P.; Acebes, J.J.; Griffiths, J.R.; Arus, C.

    2006-01-01

    OBJECT: The aim of this study was to estimate the accuracy of routine magnetic resonance (MR) imaging studies in the classification of brain tumors in terms of both cell type and grade of malignancy. METHODS: The authors retrospectively assessed the correlation between neuroimaging classifications a

  20. Does Magnetic Resonance Brain Scanning at 3.0 Tesla Pose a Hyperthermic Challenge to Term Neonates?

    Science.gov (United States)

    Cawley, Paul; Few, Karen; Greenwood, Richard; Malcolm, Paul; Johnson, Glyn; Lally, Pete; Thayyil, Sudhin; Clarke, Paul

    2016-08-01

    Next-generation 3-Tesla magnetic resonance (MR) scanners offer improved neonatal neuroimaging, but the greater associated radiofrequency radiation may increase the risk of hyperthermia. Safety data for neonatal 3-T MR scanning are lacking. We measured rectal temperatures continuously in 25 neonates undergoing 3-T brain MR imaging and observed no significant hyperthermic threat. PMID:27318382

  1. Does Magnetic Resonance Brain Scanning at 3.0 Tesla Pose a Hyperthermic Challenge to Term Neonates?

    Science.gov (United States)

    Cawley, Paul; Few, Karen; Greenwood, Richard; Malcolm, Paul; Johnson, Glyn; Lally, Pete; Thayyil, Sudhin; Clarke, Paul

    2016-08-01

    Next-generation 3-Tesla magnetic resonance (MR) scanners offer improved neonatal neuroimaging, but the greater associated radiofrequency radiation may increase the risk of hyperthermia. Safety data for neonatal 3-T MR scanning are lacking. We measured rectal temperatures continuously in 25 neonates undergoing 3-T brain MR imaging and observed no significant hyperthermic threat.

  2. Brain responses evoked by high-frequency repetitive transcranial magnetic stimulation: an event-related potential study

    NARCIS (Netherlands)

    M. Hamidi; H.A. Slagter; G. Tononi; B.R. Postle

    2010-01-01

    Background Many recent studies have used repetitive transcranial magnetic stimulation (rTMS) to study brain-behavior relationships. However, the pulse-to-pulse neural effects of rapid delivery of multiple TMS pulses are unknown largely because of TMS-evoked electrical artifacts limiting recording of

  3. Structure and dynamics of small scale magnetic fields in the solar atmosphere Results of high resolution polarimetry and image reconstruction

    Science.gov (United States)

    Janssen, K.

    2003-07-01

    Two-dimensional spectrograms were obtained at the Vacuum Tower Telescope, Tenerife, in order to study the structure of small scale magnetic fields on the Sun. The speckle reconstruction method that is used for data processing gives high resolution images and wavelength scans in left and right circular polarized light, from which magnetic field maps are calculated using the center of gravity method. The geometric similarity of magnetic structures is studied via the area- perimeter-relation, from which the Hausdorff-dimension of the rim of a structure is determined. The investigation shows that the actual value of the fractal dimension depends on the threshold that is used to determine the borders of the magnetic areas. Higher treshold values lead to smaller fractal dimensions. This can be explained by the concentration of strong magnetic fields while weak fields spread out in more complex structures. With a treshold of 80 Gauss a fractal dimension of D=1,40(5) is obtained. Furthermore, the dimension obtained by observed data is compared to the fractal dimension gained from MHD simulations. It is found that if the measurement scales are adjusted correctly the dimensions for both datasets match quite well. In a second part the dynamics of the mass motions were analysed and a coarse estimate of the energy conveyed by these movements to the magnetic field is given. The energy flux is strong enough to participate in the heating of the solar chromosphere and corona over active regions.

  4. Parameters of glucose metabolism and the aging brain: a magnetization transfer imaging study of brain macro- and micro-structure in older adults without diabetes.

    Science.gov (United States)

    Akintola, Abimbola A; van den Berg, Annette; Altmann-Schneider, Irmhild; Jansen, Steffy W; van Buchem, Mark A; Slagboom, P Eline; Westendorp, Rudi G; van Heemst, Diana; van der Grond, Jeroen

    2015-08-01

    Given the concurrent, escalating epidemic of diabetes mellitus and neurodegenerative diseases, two age-related disorders, we aimed to understand the relation between parameters of glucose metabolism and indices of pathology in the aging brain. From the Leiden Longevity Study, 132 participants (mean age 66 years) underwent a 2-h oral glucose tolerance test to assess glucose tolerance (fasted and area under the curve (AUC) glucose), insulin sensitivity (fasted and AUC insulin and homeostatic model assessment of insulin sensitivity (HOMA-IS)) and insulin secretion (insulinogenic index). 3-T brain MRI was used to detect macro-structural damage (atrophy, white matter hyper-intensities, infarcts and/or micro-bleeds) and magnetization transfer imaging (MTI) to detect loss of micro-structural homogeneity that remains otherwise invisible on conventional MRI. Macro-structurally, higher fasted glucose was significantly associated with white matter atrophy (P = 0.028). Micro-structurally, decreased magnetization transfer ratio (MTR) peak height in gray matter was associated with higher fasted insulin (P = 0.010), AUCinsulin (P = 0.001), insulinogenic index (P = 0.008) and lower HOMA-IS index (P macro-structural damage, impaired insulin action was associated more strongly with reduced micro-structural brain parenchymal homogeneity. These findings offer some insight into the association between different parameters of glucose metabolism (impairment of which is characteristic of diabetes mellitus) and brain aging.

  5. Brain magnetic resonance imaging findings in cryptogenic stroke patients under 60 years with patent foramen ovale

    International Nuclear Information System (INIS)

    Purpose: To compare magnetic resonance imaging (MRI) brain feature in cryptogenic stroke patients with patent foramen ovale (PFO), cryptogenic stroke patients without PFO and patients with cardioembolic stroke. Materials and methods: The ethics committee required neither institutional review board approval nor informed patient consent for retrospective analyses of the patients’ medical records and imaging data. The patients’ medical files were retrospectively reviewed in accordance with human subject research protocols. Ninety-two patients under 60 years of age were included: 15 with cardioembolic stroke, 32 with cryptogenic stroke with PFO and 45 with cryptogenic stroke without PFO. Diffusion-weighted imaging of brain MRI was performed by a radiologist blinded to clinical data. Univariate, Fischer's exact test for qualitative data and non-parametric Wilcoxon test for quantitative data were used. Results: There was no statistically significant difference found between MRI features of patients with PFO and those with cardioembolic stroke (p < .05). Patients without PFO present more corticosubcortical single lesions (p < .05) than patients with PFO. Patients with PFO have more often subcortical single lesions larger than 15 mm, involvement of posterior cerebral arterial territory and intracranial occlusion (p < .05) than patients with cryptogenic stroke without PFO. Conclusion: Our study suggests a cardioembolic mechanism in ischemic stroke with PFO

  6. Intensity-Curvature Measurement Approaches for the Diagnosis of Magnetic Resonance Imaging Brain Tumors

    Directory of Open Access Journals (Sweden)

    Carlo Ciulla

    2015-11-01

    Full Text Available This research presents signal-image post-processing techniques called Intensity-Curvature Measurement Approaches with application to the diagnosis of human brain tumors detected through Magnetic Resonance Imaging (MRI. Post-processing of the MRI of the human brain encompasses the following model functions: (i bivariate cubic polynomial, (ii bivariate cubic Lagrange polynomial, (iii monovariate sinc, and (iv bivariate linear. The following Intensity-Curvature Measurement Approaches were used: (i classic-curvature, (ii signal resilient to interpolation, (iii intensity-curvature measure and (iv intensity-curvature functional. The results revealed that the classic-curvature, the signal resilient to interpolation and the intensity-curvature functional are able to add additional information useful to the diagnosis carried out with MRI. The contribution to the MRI diagnosis of our study are: (i the enhanced gray level scale of the tumor mass and the well-behaved representation of the tumor provided through the signal resilient to interpolation, and (ii the visually perceptible third dimension perpendicular to the image plane provided through the classic-curvature and the intensity-curvature functional.

  7. A multi-channel magnetic induction tomography measurement system for human brain model imaging

    International Nuclear Information System (INIS)

    This paper proposes a multi-channel magnetic induction tomography measurement system for biological conductivity imaging in a human brain model. A hemispherical glass bowl filled with a salt solution is used as the human brain model; meanwhile, agar blocks of different conductivity are placed in the solution to simulate the intracerebral hemorrhage. The excitation and detection coils are fixed co-axially, and the axial gradiometer is used as the detection coil in order to cancel the primary field. On the outer surface of the glass bowl, 15 sensor units are arrayed in two circles as measurement parts, and a single sensor unit for canceling the phase drift is placed beside the glass bowl. The phase sensitivity of our system is 0.204°/S m−1 with the excitation frequency of 120 kHz and the phase noise is in the range of −0.03° to +0.05°. Only the coaxial detection coil is available for each excitation coil; therefore, 15 phase data are collected in each measurement turn. Finally, the two-dimensional images of conductivity distribution are obtained using an interpolation algorithm. The frequency-varying experiment indicates that the imaging quality becomes better as the excitation frequency is increased

  8. Brain magnetic resonance imaging findings in cryptogenic stroke patients under 60 years with patent foramen ovale

    Energy Technology Data Exchange (ETDEWEB)

    Boutet, Claire, E-mail: claire.boutet@chu-st-etienne.fr [Department of Radiology, University Hospital of Saint-Etienne (France); Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Rouffiange-Leclair, Laure, E-mail: laurerouffiange@hotmail.com [Department of Radiology, University Hospital of Saint-Etienne (France); Garnier, Pierre, E-mail: pierre.garnier@chu-st-etienne.fr [Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Department of Neurology, University Hospital of Saint-Etienne (France); Quenet, Sara, E-mail: sara.quenet@chu-st-etienne.fr [Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Delsart, Daphné, E-mail: daphne.delsart@hotmail.fr [Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Department of Therapeutic Medicine, CHU Saint-Etienne, Hôpital Nord, Saint-Etienne (France); Inserm, CIE3, F-42055 Saint-Etienne (France); Varvat, Jérôme, E-mail: jvarvat@9online.fr [Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Department of Neurology, University Hospital of Saint-Etienne (France); Epinat, Magali, E-mail: magali.epinat@chu-st-etienne.fr [Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Department of Neurology, University Hospital of Saint-Etienne (France); Schneider, Fabien, E-mail: fabien.schneider@univ-st-etienne.fr [Department of Radiology, University Hospital of Saint-Etienne (France); Thrombosis Research Group EA 3065, Jean Monnet University, Saint-Etienne (France); Antoine, Jean-Christophe, E-mail: j.christophe.antoine@chu-st-etienne.fr [Department of Neurology, University Hospital of Saint-Etienne (France); Lyon Neuroscience Research Center, INSERM U1028 – CNRS UMR5292 (France); EA 4338, Jean Monnet University, Saint-Etienne (France); and others

    2014-05-15

    Purpose: To compare magnetic resonance imaging (MRI) brain feature in cryptogenic stroke patients with patent foramen ovale (PFO), cryptogenic stroke patients without PFO and patients with cardioembolic stroke. Materials and methods: The ethics committee required neither institutional review board approval nor informed patient consent for retrospective analyses of the patients’ medical records and imaging data. The patients’ medical files were retrospectively reviewed in accordance with human subject research protocols. Ninety-two patients under 60 years of age were included: 15 with cardioembolic stroke, 32 with cryptogenic stroke with PFO and 45 with cryptogenic stroke without PFO. Diffusion-weighted imaging of brain MRI was performed by a radiologist blinded to clinical data. Univariate, Fischer's exact test for qualitative data and non-parametric Wilcoxon test for quantitative data were used. Results: There was no statistically significant difference found between MRI features of patients with PFO and those with cardioembolic stroke (p < .05). Patients without PFO present more corticosubcortical single lesions (p < .05) than patients with PFO. Patients with PFO have more often subcortical single lesions larger than 15 mm, involvement of posterior cerebral arterial territory and intracranial occlusion (p < .05) than patients with cryptogenic stroke without PFO. Conclusion: Our study suggests a cardioembolic mechanism in ischemic stroke with PFO.

  9. {sup 1}H magnetic resonance spectroscopy in the diagnosis of paediatric low grade brain tumours

    Energy Technology Data Exchange (ETDEWEB)

    Orphanidou-Vlachou, E., E-mail: eleni.orphanidou@googlemail.com [School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Birmingham Children' s Hospital NHS Foundation Trust, Whittall Street, Birmingham, B4 6NH (United Kingdom); Auer, D., E-mail: dorothee.auer@nottingham.ac.uk [Division of Academic Radiology, School of Medical and Surgical Sciences, The University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Children' s Brain Tumour Research Centre, Queens Medical Centre, University of Nottingham (United Kingdom); Brundler, M.A., E-mail: marie-anne.brundler@bch.nhs.uk [Birmingham Children' s Hospital NHS Foundation Trust, Whittall Street, Birmingham, B4 6NH (United Kingdom); Davies, N.P., E-mail: nigel.davies@nhs.net [School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Birmingham Children' s Hospital NHS Foundation Trust, Whittall Street, Birmingham, B4 6NH (United Kingdom); Department of Medical Physics, University Hospitals Birmingham NHS Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB (United Kingdom); Jaspan, T., E-mail: tim.jaspan@nuh.nhs.uk [Children' s Brain Tumour Research Centre, Queens Medical Centre, University of Nottingham (United Kingdom); MacPherson, L., E-mail: Lesley.MacPherson@bch.nhs.uk [Birmingham Children' s Hospital NHS Foundation Trust, Whittall Street, Birmingham, B4 6NH (United Kingdom); Natarajan, K., E-mail: Kal.Natarajan@uhb.nhs.uk [Birmingham Children' s Hospital NHS Foundation Trust, Whittall Street, Birmingham, B4 6NH (United Kingdom); Department of Medical Physics, University Hospitals Birmingham NHS Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB (United Kingdom); and others

    2013-06-15

    Introduction: Low grade gliomas are the commonest brain tumours in children but present in a myriad of ways, each with its own treatment challenges. Conventional MRI scans play an important role in their management but have limited ability to identify likely clinical behaviour. The aim of this study is to investigate {sup 1}H magnetic resonance spectroscopy (MRS) as a method for detecting differences between the various low grade gliomas and related tumours in children. Patients and methods: Short echo time single voxel {sup 1}H MRS at 1.5 or 3.0 T was performed prior to treatment on children with low grade brain tumours at two centres and five MR scanners, 69 cases had data which passed quality control. MRS data was processed using LCModel to give mean spectra and metabolite concentrations which were compared using T-tests, ANOVA, Receiver Operator Characteristic curves and logistic regression in SPSS. Results: Significant differences were found in concentrations of key metabolites between glioneuronal and glial tumours (T-test p < 0.05) and between most of the individual histological subtypes of low grade gliomas. The discriminatory metabolites identified, such as choline and myoinositol, are known tumour biomarkers. In the set of pilocytic astrocytomas and unbiopsied optic pathway gliomas, significant differences (p < 0.05, ANOVA) were found in metabolite profiles of tumours depending on location and patient neurofibromatosis type 1 status. Logistic regression analyses yielded equations which could be used to assess the probability of a tumour being of a specific type. Conclusions: MRS can detect subtle differences between low grade brain tumours in children and should form part of the clinical assessment of these tumours.

  10. Effects of hormone replacement therapy on magnetic resonance imaging of brain parenchyma hyperintensities in postmenopausal women

    Institute of Scientific and Technical Information of China (English)

    Yan-yong LIU; Qin-sheng GE; Ping-ping ZUO; Ling HU; Chao JI; Dong-wen CHEN; Xi SHEN; Nan YANG; Yun YUE; Jing-mei JIANG; Xia HONG

    2009-01-01

    Aim:To apply 3.0 magnetic resonance imaging (MRI) to study the effects of long-term,low dose hormone replacement therapy (HRT) on the brain parenchyma of postmenopausal women.Methods:A total of 155 postmenopausal healthy female medical staff members from Peking Union Medical College Hospital were enrolled.The HRT group was composed of 71 subjects who had been given a low dose of HRT for over 4 years,while 84 women who had never been given HRT were enrolled in the control group.The Mini-Mental State Examination (MMSE) was used to evaluate mental state,and an Enzyme-Linked ImmunoSorbent Assay (ELISA) was used to detect plasma levels of sex hormones.In addition,all participants were subjected to an MRI,including axial T2 weighted imaging (T2WI),fluid-attenuated inversion recovery (FLAIR),T1 weighted imaging (TIWI,oblique coronal,vertical to the hippocampus,slice thickness 3 mm without gaps),and a 3D image of the whole brain.Results:The ELISA showed that the plasma level of estradiol in the HRT group was significantly higher than that in the control group (Pbrain parenchyma.

  11. Limitations on the resolution and suitability of global gravity and magnetic models for geological interpretation: A user health warning!

    Science.gov (United States)

    Fairhead, J. D.; Somerton, I. W.

    2011-12-01

    There have been major advances in the generation of global gravity and crustal magnetic models that are now down loadable from the Internet. All models have variable spatial resolution which is not always readily apparent when viewing these models. The global models include: 1) Free air gravity: EGM08 (5'), Danish DTU(1') and Sandwell and Smith V16.1 (1'). 2) TMI crustal magnetic: WDMAM (3') and EMAG3 (3'), where grid cell size is in arc minutes, where 1'≈ 2 km Both models can be spectrally divided into Long wavelength components: that are very well constrained and are derived from satellite observations. For Free air gravity: wavelengths > 150 km from Grace and for TMI crustal magnetic:wavlengths > 400 km from CHAMP MF6 Shorter wavelength components: The spatial resolution is very dependent on the data coverage of the terrestrial (ground, ship and airborne) surveys and are discussed below Gravity Model: The gravity model is expressed as the Free air gravity anomaly. For marine and large inland water areas the data used are derived from satellite altimeter measurements that generate a spatial gravity resolution of 15 to 20 km (full wavelength) from 3 to 4 km spaced orbital track data. For onshore areas the data coverage is highly variable from no data (e.g. interior Angola) to more than adequate coverage (e.g. Europe). To infill data gaps, free air correction values derived from the SRTM topography data were used. This results in a free air anomaly grid that appears to have full spectral content down to the resolution of the model. Locating where the data gaps exist is difficult, since the land gravity survey coverage for EGM08, used by all models, has not been released. A further resolution problem is that many large surveys used in EGM08 have been decimated to preserve their commercial value (e.g. GETECH input grids were decimated to at least 15' grid). TMI Crustal Magnetic Model: For marine areas these models suffer even larger problems in that the sparsity of

  12. The etiology of cirrhosis is a strong determinant of brain reserve: A multimodal magnetic resonance imaging study.

    Science.gov (United States)

    Ahluwalia, Vishwadeep; Wade, James B; Moeller, F Gerard; White, Melanie B; Unser, Ariel B; Gavis, Edith A; Sterling, Richard K; Stravitz, R Todd; Sanyal, Arun J; Siddiqui, Mohammad S; Puri, Puneet; Luketic, Velimir; Heuman, Douglas M; Fuchs, Michael; Matherly, Scott; Bajaj, Jasmohan S

    2015-09-01

    Poor brain reserve in alcoholic cirrhosis could worsen insight regarding disease severity and increase the patients' vulnerability toward further deterioration. The aim of this study was to analyze brain reserve in abstinent alcoholic cirrhotic (Alc) patients compared to nonalcoholic cirrhotic (Nalc) patients in the context of hepatic encephalopathy (HE) and to evaluate relative change in brain reserve between groups over time and before and after elective transjugular intrahepatic portosystemic shunt (TIPS) placement. The cross-sectional study included 46 Alc and 102 Nalc outpatients with or without HE. Cognitive tests were followed by magnetic resonance imaging (MRI), including proton magnetic resonance spectroscopy (1 H-MRS), diffusion tensor imaging, and T1-weighted imaging. The prospective study included 1H-MRS on a subset of 10 patients before and after TIPS placement. Another subset of 26 patients underwent (1) H-MRS at least 1 year apart. For the cross-sectional study, Alc patients were worse on cognitive tests than Nalc patients. MRI results suggest a greater effect of hyperammonemia, brain edema, and significantly higher cortical damage in Alc as compared to Nalc patients. The effect of HE status on cognitive tests and brain reserve was more marked in the Nalc than in the Alc group. For the TIPS study, Nalc patients showed a greater adverse relative change after TIPS compared to the Alc group. At 1-year follow-up, both groups remained stable between the 2 visits. However, Alc patients continued to show poor brain reserve compared to Nalc patients over time. In conclusion, Alc patients, despite abstinence, have a poor brain reserve, whereas Nalc patients have a greater potential for brain reserve deterioration after HE and TIPS. Information regarding the brain reserve in cirrhosis could assist medical teams to refine their communication and monitoring strategies for different etiologies.

  13. Unresolved Mixed Polarity Magnetic Fields at Flux Cancellation Site in Solar Photosphere at 0".3 Spatial Resolution

    CERN Document Server

    Kubo, Masahito; Lites, Bruce W

    2014-01-01

    This is a follow-up investigation of a magnetic-flux cancellation event at a polarity inversion line (PIL) on the Sun observed with the spectropolarimeter on board Hinode. Anomalous circular polarization (Stokes V) profiles are observed in the photosphere along the PIL at the cancellation sites. Kubo et al. (2010) previously reported that the theoretically expected horizontal fields between the canceling opposite-polarity magnetic elements in this event are not detected at granular scales. We show that the observed anomalous Stokes V profiles are reproduced successfully by adding the nearly symmetric Stokes V profiles observed at pixels immediately adjacent to the PIL. This result suggests that these observed anomalous Stokes V profiles are not indications of a flux removal process, but are the result of either a mixture of unresolved, opposite-polarity magnetic elements or the unresolved width of the PIL, at an estimated resolution element of about 0".3. The hitherto undetected flux removal process accountin...

  14. Whole-brain calcium imaging with cellular resolution in freely behaving Caenorhabditis elegans

    Science.gov (United States)

    Nguyen, Jeffrey; Shipley, Frederick; Linder, Ashley; Plummer, George; Liu, Mochi; Setru, Sagar; Shaevitz, Joshua; Leifer, Andrew

    The ability to acquire large-scale recordings of neuronal activity in awake and unrestrained animals is needed to provide new insights into how populations of neurons generate animal behavior. Acquiring this data, however, is challenging because it is difficult to track and image individual neurons as an animal deforms its posture and moves many body lengths. Here, we present an instrument capable of recording intracellular calcium transients from the majority of neurons in the head of a freely behaving Caenorhabditis elegans with cellular resolution while simultaneously recording the animal's position, posture, and locomotion. 3D volumetric fluorescent images of neurons expressing the calcium indicator GCaMP6s are recorded at 6 head-volumes/s using spinning disk confocal microscopy. At the same time, we record low magnification images of the animal to measure the animals behavior and track its head as it moves. We develop a time independent neuronal matching algorithm that uses non-rigid point set registration and machine learning to correctly match neurons across time. Using this method, we are able to observe calcium transients from up to 90 neurons for over 4 min and correlate the neural activity with the animal's behavior.

  15. Coupling of transient near infrared photonic with magnetic nanoparticle for potential dissipation-free biomedical application in brain

    Science.gov (United States)

    Sagar, Vidya; Atluri, V. S. R.; Tomitaka, A.; Shah, P.; Nagasetti, A.; Pilakka-Kanthikeel, S.; El-Hage, N.; McGoron, A.; Takemura, Y.; Nair, M.

    2016-07-01

    Combined treatment strategies based on magnetic nanoparticles (MNPs) with near infrared ray (NIR) biophotonic possess tremendous potential for non-invasive therapeutic approach. Nonetheless, investigations in this direction have been limited to peripheral body region and little is known about the potential biomedical application of this approach for brain. Here we report that transient NIR exposure is dissipation-free and has no adverse effect on the viability and plasticity of major brain cells in the presence or absence superparamagnetic nanoparticles. The 808 nm NIR laser module with thermocouple was employed for functional studies upon NIR exposure to brain cells. Magnetic nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic laser scattering (DLS), and vibrating sample magnetometer (VSM). Brain cells viability and plasticity were analyzed using electric cell-substrate impedance sensing system, cytotoxicity evaluation, and confocal microscopy. When efficacious non-invasive photobiomodulation and neuro-therapeutical targeting and monitoring to brain remain a formidable task, the discovery of this dissipation-free, transient NIR photonic approach for brain cells possesses remarkable potential to add new dimension.

  16. The Relationship Between Brain Oscillatory Activity and Therapeutic Effectiveness of Transcranial Magnetic Stimulation in the Treatment of Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Andrew Francis Leuchter

    2013-02-01

    Full Text Available Major Depressive Disorder (MDD is marked by disturbances in brain functional connectivity. This connectivity is modulated by rhythmic oscillations of brain electrical activity, which enable coordinated functions across brain regions. Oscillatory activity plays a central role in regulating thinking and memory, mood, cerebral blood flow, and neurotransmitter levels, and restoration of normal oscillatory patterns is associated with effective treatment of MDD. Repetitive Transcranial Magnetic Stimulation (rTMS is a robust treatment for MDD, but the mechanism of action (MOA of its benefits for mood disorders remains incompletely understood. Benefits of rTMS have been tied to enhanced neuroplasticity in specific brain pathways. We summarize here the evidence that rTMS entrains and resets thalamocortical oscillators, normalizes regulation and facilitates reemergence of intrinsic cerebral rhythms, and through this mechanism restores normal brain function. This entrainment and resetting may be a critical step in engendering neuroplastic changes and the antidepressant effects of rTMS. It may be possible to modify the method of rTMS administration to enhance this mechanism of action and achieve better antidepressant effectiveness. We propose that rTMS can be administered: 1 synchronized to a patient’s individual alpha rhythm (IAF, or synchronized rTMS (sTMS; 2 as a low magnetic field strength sinusoidal wave form; and, 3 broadly to multiple brain areas simultaneously. We present here the theory and evidence indicating that these modifications could enhance the therapeutic effectiveness of rTMS for the treatment of MDD.

  17. Ultrasound/Magnetic Targeting with SPIO-DOX-Microbubble Complex for Image-Guided Drug Delivery in Brain Tumors

    Science.gov (United States)

    Fan, Ching-Hsiang; Cheng, Yu-Hang; Ting, Chien-Yu; Ho, Yi-Ju; Hsu, Po-Hung; Liu, Hao-Li; Yeh, Chih-Kuang

    2016-01-01

    One of the greatest challenges in the deployment of chemotherapeutic drugs against brain tumors is ensuring that sufficient drug concentrations reach the tumor, while minimizing drug accumulation at undesired sites. Recently, injection of therapeutic agents following blood-brain barrier (BBB) opening by focused ultrasound (FUS) with microbubbles (MBs) has been shown to enhance drug delivery in targeted brain regions. Nevertheless, the distribution and quantitative deposition of agents delivered to the brain are still hard to estimate. Based on our previous work on superparamagnetic iron oxide (SPIO)-loaded MBs, we present a novel theranostic complex of SPIO-Doxorubicin (DOX)-conjugated MB (SD-MB) for drug delivery to the brain. Magnetic labeling of the drug enables direct visualization via magnetic resonance imaging, and also facilitates magnetic targeting (MT) to actively enhance targeted deposition of the drug. In a rat glioma model, we demonstrated that FUS sonication can be used with SD-MBs to simultaneously facilitate BBB opening and allow dual ultrasound/magnetic targeting of chemotherapeutic agent (DOX) delivery. The accumulation of SD complex within brain tumors can be significantly enhanced by MT (25.7 fold of DOX, 7.6 fold of SPIO). The change in relaxation rate R2 (1/T2) within tumors was highly correlated with SD deposition as quantified by high performance liquid chromatography (R2 = 0.93) and inductively coupled plasma-atomic emission spectroscopy (R2 = 0.94), demonstrating real-time monitoring of DOX distribution. Our results suggest that SD-MBs can serve as multifunction agents to achieve advanced molecular theranostics. PMID:27446489

  18. Neurosyphilis with dementia and bilateral hippocampal atrophy on brain magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Mehrabian Shima

    2012-09-01

    Full Text Available Abstract Background This article reports a rare case of active neurosyphilis in a man with mild to moderate dementia and marked hippocampal atrophy, mimicking early onset Alzheimer’s disease. Few cases have so far described bilateral hippocampal atrophy mimicking Alzheimer’s disease in neurosyphilis. Case presentation The patient presented here is a 33 year old Bulgarian male, whose clinical features include progressive cognitive decline and behavioral changes over the last 18 months. Neuropsychological examination revealed mild to moderate dementia (Mini Mental State Examination score was 16/30 with impaired memory and attention, and executive dysfunction. Pyramidal, and extrapyramidal signs, as well as dysarthria and impairment in coordination, were documented. Brain magnetic resonance imaging showed cortical atrophy with noticeable bilateral hippocampal atrophy. The diagnosis of active neurosyphilis was based on positive results of the Venereal Disease Research Laboratory test/Treponema pallidum hemagglutination reactions in blood and cerebrospinal fluid samples. In addition, cerebrospinal fluid analysis showed pleocytosis and elevated protein levels. High-dose intravenous penicillin therapy was administered. At 6 month follow up, improvements were noted clinically, on neuropsychological examinations, and in cerebrospinal fluid samples. Conclusion This case underlines the importance of early diagnosis of neurosyphilis. The results suggest that neurosyphilis should be considered when magnetic resonance imaging results indicate mesiotemporal abnormalities and hippocampal atrophy. Neurosyphilis is a treatable condition which requires early aggressive antibiotic therapy.

  19. Neurosyphilis with dementia and bilateral hippocampal atrophy on brain magnetic resonance imaging

    International Nuclear Information System (INIS)

    Full text: Background: This article reports a rare case of active neurosyphilis in a 33-years-old man with mild to moderate dementia and marked hippocampal atrophy, mimicking early onset Alzheimer's disease. Few number of cases described bilateral hippocampal atrophy mimicking Alzheimer's disease in neurosyphilis. Case presentation: The clinical feature is characterized by a progressive cognitive decline and behavioral changes for the last 18 months. Neuropsychological examination revealed mild to moderate dementia (MMSE=16) with impaired memory, attention and executive dysfunction. Pyramidal, extrapyramidal signs, dysarthria and impairment in coordination were documented. Brain magnetic resonance imaging showed cortical atrophy with marked bilateral hippocampal atrophy. The diagnosis of active neurosyphilis was based on positive results of Venereal Disease Research Laboratory test - Treponema Pallidum. Hemagglutination reactions in blood and cerebrospinal fluid samples. In addition, cerebrospinal fluid analysis showed pleocytosis and elevated protein levels. High dose intravenous penicillin therapy was administered. During the follow up examination at 6 month, the clinical signs, and neuropsychological examinations, and cerebrospinal fluid samples showed improvement. Conclusion: This case underlines the importance of early diagnosis of neurosyphilis. The results suggest that neurosyphilis should be considered when magnetic resonance imaging results indicate mesiotemporal abnormalities and hippocampal atrophy. Neurosyphilis is a treatable condition and needs early aggressive antibiotic therapy

  20. The value of multimodal magnetic resonance imaging in the differential diagnosis of glioma recurrence and radiation brain injury

    Directory of Open Access Journals (Sweden)

    Guang-zhi GE

    2015-11-01

    Full Text Available Objective  To explore the application of a combination of diFFusion weighted imaging (DWI, perfusion weighted imaging (PWI and magnetic resonance spectroscopy (MRS in the differential diagnosis of glioma recurrence and radiation brain injury. Methods The clinical and imaging data of 32 patients were retrospectively analyzed, including 15 cases of glioma recurrence and 17 cases of radiation brain injury, admitted from Jan. 2011 to Dec. 2013 in General Hospital of Beijing Command. The DWI, PWI and MRS data of the 32 patients were retrospectively analyzed. The following values were compared between abnormal enhancement area and contralateral normal area: magnetic resonance apparent diFFusion coeFFcient (ADC, relative cerebral blood flow (rCBF, relative cerebral blood volume (rCBV, relative mean transit time (rMTT, choline/creatine (Cho/Cr and choline/N-acetyl aspartate (Cho/ NAA ratio. Results No statistical significance of ADC and rMTT values was found between glioma recurrence group and radiation brain injury group (P>0.05; The maximum and average rCBF and rCBV values were significantly higher in glioma recurrence group than in radiation brain injury group (P0.05. The ratios of Cho/Cr and Cho/NAA were higher in glioma recurrence group than in radiation brain injury group (P<0.05. The diagnostic sensitivity of PWI to glioma recurrence was 80.0%, of MRS was 73.3%, and of PWI combined with MRS was 93.3%. The diagnostic sensitivity of PWI to radiation brain injury was 82.4%, of MRS was 70.6%, and of PWI combined with MRS was 88.2%. Conclusion Combined application of multimodal magnetic resonance imaging technology may improve the diagnostic accuracy to glioma recurrence and radiation brain injury, thus provide a good guidance for clinical treatment. DOI: 10.11855/j.issn.0577-7402.2015.11.13

  1. Ultra-high-resolution Observations of MHD Waves in Photospheric Magnetic Structures

    CERN Document Server

    Jess, David B

    2015-01-01

    Here we review the recent progress made in the detection, examination, characterisation and interpretation of oscillations manifesting in small-scale magnetic elements in the solar photosphere. This region of the Sun's atmosphere is especially dynamic, and importantly, permeated with an abundance of magnetic field concentrations. Such magnetic features can span diameters of hundreds to many tens of thousands of km, and are thus commonly referred to as the `building blocks' of the magnetic solar atmosphere. However, it is the smallest magnetic elements that have risen to the forefront of solar physics research in recent years. Structures, which include magnetic bright points, are often at the diffraction limit of even the largest of solar telescopes. Importantly, it is the improvements in facilities, instrumentation, imaging techniques and processing algorithms during recent years that have allowed researchers to examine the motions, dynamics and evolution of such features on the smallest spatial and temporal ...

  2. Transcranial magnetic stimulation of the brain: guidelines for pain treatment research.

    Science.gov (United States)

    Klein, Max M; Treister, Roi; Raij, Tommi; Pascual-Leone, Alvaro; Park, Lawrence; Nurmikko, Turo; Lenz, Fred; Lefaucheur, Jean-Pascal; Lang, Magdalena; Hallett, Mark; Fox, Michael; Cudkowicz, Merit; Costello, Ann; Carr, Daniel B; Ayache, Samar S; Oaklander, Anne Louise

    2015-09-01

    Recognizing that electrically stimulating the motor cortex could relieve chronic pain sparked development of noninvasive technologies. In transcranial magnetic stimulation (TMS), electromagnetic coils held against the scalp influence underlying cortical firing. Multiday repetitive transcranial magnetic stimulation (rTMS) can induce long-lasting, potentially therapeutic brain plasticity. Nearby ferromagnetic or electronic implants are contraindications. Adverse effects are minimal, primarily headaches. Single provoked seizures are very rare. Transcranial magnetic stimulation devices are marketed for depression and migraine in the United States and for various indications elsewhere. Although multiple studies report that high-frequency rTMS of the motor cortex reduces neuropathic pain, their quality has been insufficient to support Food and Drug Administration application. Harvard's Radcliffe Institute therefore sponsored a workshop to solicit advice from experts in TMS, pain research, and clinical trials. They recommended that researchers standardize and document all TMS parameters and improve strategies for sham and double blinding. Subjects should have common well-characterized pain conditions amenable to motor cortex rTMS and studies should be adequately powered. They recommended standardized assessment tools (eg, NIH's PROMIS) plus validated condition-specific instruments and consensus-recommended metrics (eg, IMMPACT). Outcomes should include pain intensity and qualities, patient and clinician impression of change, and proportions achieving 30% and 50% pain relief. Secondary outcomes could include function, mood, sleep, and/or quality of life. Minimum required elements include sample sources, sizes, and demographics, recruitment methods, inclusion and exclusion criteria, baseline and posttreatment means and SD, adverse effects, safety concerns, discontinuations, and medication-usage records. Outcomes should be monitored for at least 3 months after initiation

  3. Performance evaluation of three-dimensional position-sensitive CdTe detector blocks for an ultra-high resolution brain PET scanner

    International Nuclear Information System (INIS)

    We have developed an ultra-high resolution human brain positron emission tomography (PET) scanner with the resolution of less than 1 mm FWHM, in which cadmium telluride (CdTe) semiconductor detectors were used. As the detector of the scanner, we have developed a two-dimensional position-sensitive CdTe detector (2D-PSD) which was developed in our previous study. The 2D-PSD can detect gamma rays with a position resolution of approximately 1.2 mm. We developed a three-dimensional position-sensitive CdTe detector block (3D-PSD block) by stacking 80 2D-PSDs which were connected to subsequent circuits (amplifiers, analog to digital converters, and other data processing circuits). We constructed an ultra-high resolution semiconductor brain PET gantry placing the ten 3D-PSD blocks in decagonal arrangement. In this paper, we checked all 2D-PSDs and classified their performance. As the results, we confirmed that our 3D-PSD blocks can be used to the ultra-high resolution human brain PET. We made a circuit to reduce the dead time due to restoration from polarization phenomena in CdTe detector and we could stabilize count rates. (author)

  4. A Magnetic Thermometer for High-Resolution 10 mK Scale Thermometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative thin-film magnetic thermometer with integrated superconducting quantum interference device (SQUID) readout is described for fast, precision...

  5. Crocus sativus Petals: Waste or Valuable Resource? The Answer of High-Resolution and High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance.

    Science.gov (United States)

    Righi, Valeria; Parenti, Francesca; Tugnoli, Vitaliano; Schenetti, Luisa; Mucci, Adele

    2015-09-30

    Intact Crocus sativus petals were studied for the first time by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy, revealing the presence of kinsenoside (2) and goodyeroside A (3), together with 3-hydroxy-γ-butyrolactone (4). These findings were confirmed by HR-NMR analysis of the ethanol extract of fresh petals and showed that, even though carried out rapidly, partial hydrolysis of glucopyranosyloxybutanolides occurs during extraction. On the other hand, kaempferol 3-O-sophoroside (1), which is "NMR-silent" in intact petals, is present in extracts. These results suggest to evaluate the utilization of saffron petals for phytopharmaceutical and nutraceutical purposes to exploit a waste product of massive production of commercial saffron and point to the application of HR-MAS NMR for monitoring bioactive compounds directly on intact petals, avoiding the extraction procedure and the consequent hydrolysis reaction.

  6. Brain Basics

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    Full Text Available ... Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take pictures of ... to slow or stop them from progressing. Functional magnetic resonance imaging (fMRI) is another important research tool in understanding ...

  7. Brain Basics

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    Full Text Available ... Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses magnetic fields to take ... to slow or stop them from progressing. Functional magnetic resonance imaging (fMRI) is another important research tool in ...

  8. Zebrafish brain lipid characterization and quantification by ¹H nuclear magnetic resonance spectroscopy and MALDI-TOF mass spectrometry.

    Science.gov (United States)

    van Amerongen, Yvonne F; Roy, Upasana; Spaink, Herman P; de Groot, Huub J M; Huster, Daniel; Schiller, Jürgen; Alia, A

    2014-06-01

    Lipids play an important role in many neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, and Huntington's disease. Zebrafish models for these diseases have been recently developed. The detailed brain lipid composition of the adult zebrafish is not known, and therefore, the representativeness of these models cannot be properly evaluated. In this study, we characterized the total lipid composition of healthy adult zebrafish using (1)H nuclear magnetic resonance spectroscopy. A close resemblance of the zebrafish brain composition is shown in comparison to the human brain. Moreover, several lipids involved in the pathogenesis of neurodegenerative diseases (i.e., cholesterol, phosphatidylcholine, docosahexaenoic acid, and further, polyunsaturated fatty acids) are detected and quantified. These lipids might represent useful biomarkers in future research toward human therapies. Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry coupled with high-performance thin-layer chromatography was used for further characterization of zebrafish brain lipids. Our results show that the lipid composition of the zebrafish brain is rather similar to the human brain and thus confirms that zebrafish represents a good model for studying various brain diseases.

  9. Can fruits and vegetables be used as substitute phantoms for normal human brain tissues in magnetic resonance imaging?

    International Nuclear Information System (INIS)

    Various custom-made phantoms designed to optimize magnetic resonance imaging (MRI) sequences have been created and subsequently reported in Japanese Society of Radiological Technology (JSRT). However, custom-made phantoms that correctly match the T1-value and T2-values of human brain tissue (gray matter and white matter) cannot be made easily or quickly. The aim of this project was to search for alternative materials, such as fruits and vegetables, for optimizing MRI sequences. The following eight fruits and vegetables were investigated: apple, tomato, melon, apple mango (Mangifera indica), banana, avocado, peach, and eggplant. Their potential was studied for use in modeling phantoms of normal human brain tissues. MRI (T1- and T2-weighted sequences) was performed on the human brain and the fruits and vegetables using various concentrations of contrast medium (gadolinium) in the same size tubes as the custom-made phantom. The authors compared the signal intensity (SI) in human brain tissue (gray matter and white matter) with that of the fruits and the custom-made phantom. The T1 and T2 values were measured for banana tissue and compared with those for human brain tissue in the literature. Our results indicated that banana tissue is similar to human brain tissue (both gray matter and white matter). Banana tissue can thus be employed as an alternative phantom for the human brain for the purpose of MRI. (author)

  10. Tracing Activity across the Whole Brain Neural Network with Optogenetic Functional Magnetic Resonance Imaging (ofMRI

    Directory of Open Access Journals (Sweden)

    Jin Hyung eLee

    2011-10-01

    Full Text Available Despite the overwhelming need, there has been a relatively large gap in our ability to trace network level activity across the brain. The complex dense wiring of the brain makes it extremely challenging to understand a specific set of neuron’s activity and their communication beyond a few synapses. Recent development of the optogenetic functional magnetic resonance imaging (ofMRI provides a new impetus for the study of the brain circuit by enabling causal tracing of the brain circuit activity across the whole brain. Brain circuit elements can be selectively triggered based on their genetic identity, cell body location, and/or their axonal projection target with temporal precision while the resulting network response is monitored non-invasively with unprecedented spatial and temporal accuracy. With further studies including technological innovations to bring ofMRI to its full potential, ofMRI is expected to play an important role in our system-level understanding of the brain circuit mechanism.

  11. Mapping primary gyrogenesis during fetal development in primate brains: high-resolution in utero structural MRI study of fetal brain development in pregnant baboons

    Directory of Open Access Journals (Sweden)

    Peter Kochunov

    2010-05-01

    Full Text Available The global and regional changes in the fetal cerebral cortex in primates were mapped during primary gyrification (PG; weeks 17-25 of 26 weeks total gestation. Studying pregnant baboons using high-resolution MRI in utero, measurements included cerebral volume, cortical surface area, gyrification index and length and depth of ten primary cortical sulci. Seven normally developing fetuses were imaged in two animals longitudinally and sequentially. We compared these results to those on PG that from the ferret studies and analyzed them in the context of our recent studies of phylogenetics of cerebral gyrification. We observed that in both primates and non-primates, the cerebrum undergoes a very rapid transformation into the gyrencephalic state, subsequently accompanied by an accelerated growth in brain volume and cortical surface area. However, PG trends in baboons exhibited some critical differences from those observed in ferrets. For example, in baboons, the growth along the long (length axis of cortical sulci was unrelated to the growth along the short (depth axis and far outpaced it. Additionally, the correlation between the rate of growth along the short sulcal axis and heritability of sulcal depth was negative and approached significance (r=-0.60;p<.10, while the same trend for long axis was positive and not significant (p=0.3;p=0.40. These findings, in an animal that shares a highly orchestrated pattern of PG with humans, suggest that ontogenic processes that influence changes in sulcal length and depth are diverse and possibly driven by different factors in primates than in non-primates.

  12. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    Energy Technology Data Exchange (ETDEWEB)

    Caiazzo, Giuseppina; Trojsi, Francesca; Cirillo, Mario; Tedeschi, Gioacchino [MRI Research Center SUN-FISM-Neurological Institute for Diagnosis and Care ' ' Hermitage Capodimonte' ' , Naples (Italy); Second University of Naples, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Naples (Italy); Esposito, Fabrizio [University of Salerno, Department of Medicine and Surgery, Baronissi (Salerno) (Italy); Maastricht University, Department of Cognitive Neuroscience, Maastricht (Netherlands)

    2016-02-15

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm{sup 2}, 54 gradient directions) and low angular resolution (b = 1000 s/mm{sup 2}, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  13. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    International Nuclear Information System (INIS)

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm2, 54 gradient directions) and low angular resolution (b = 1000 s/mm2, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  14. qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution

    Directory of Open Access Journals (Sweden)

    Maximilian Schneiderbauer

    2012-02-01

    Full Text Available Magnetic force microscopy (MFM allows one to image the domain structure of ferromagnetic samples by probing the dipole forces between a magnetic probe tip and a magnetic sample. The magnetic domain structure of the sample depends on the alignment of the individual atomic magnetic moments. It is desirable to be able to image both individual atoms and domain structures with a single probe. However, the force gradients of the interactions responsible for atomic contrast and those causing domain contrast are orders of magnitude apart, ranging from up to 100 Nm−1 for atomic interactions down to 0.0001 Nm−1 for magnetic dipole interactions. Here, we show that this gap can be bridged with a qPlus sensor, with a stiffness of 1800 Nm−1 (optimized for atomic interaction, which is sensitive enough to measure millihertz frequency contrast caused by magnetic dipole–dipole interactions. Thus we have succeeded in establishing a sensing technique that performs scanning tunneling microscopy, atomic force microscopy and MFM with a single probe.

  15. Identification of brain metabolites by magnetic resonance spectroscopy in MND/ALS.

    Science.gov (United States)

    Knight, J M; Jones, A P; Redmond, J P; Shaw, I C

    1996-08-01

    Magnetic resonance spectroscopy (MRS) has provided a novel means of studying the brain biochemistry of motor neurone disease/amyotrophic lateral sclerosis (MND/ALS) patients in vivo in situ. Previous studies have demonstrated changes in the ratios of areas under specific spectral peaks in MND/ALS patients (Jones et al., 1995). However, the significance of such findings cannot be fully elucidated without first ascertaining the biochemical identity of each peak. Each peak in a MRS spectrum corresponds to the resonance of specific protons in a particular chemical environment. Many biochemicals contain similar protons in similar environments so it is possible that a single spectral peak could represent protons from more than one biochemical. In this study of major brain MRS peaks we have demonstrated that peaks are potentially composed of a number of protons from different chemicals. For example, the peak at chemical shift 2.01 ppm, conventionally recognised as the neurotransmitter N-acetyl aspartate, may actually be a result of the protons of the N-acetyl moiety (Frahm et al., 1991). We have consequently shown that other N-acetylated compounds such as N-acetyl glutamate are also capable of producing a peak here, whereas their non-acetylated derivatives are not. We have also shown GABA is capable of producing a peak at chemical shift 3.00 ppm, a peak which is generally assigned to creatine/phosphocreatine. These findings have important implications in the identification of spectral peaks in MRS studies and in the interpretation of spectral differences between MND patients and controls. PMID:8899668

  16. Microvascular permeability of brain astrocytoma with contrastenhanced magnetic resonance imaging: correlation analysis with histopathologic grade

    Institute of Scientific and Technical Information of China (English)

    JIA Zhong-zheng; GENG Dao-ying; LIU Ying; CHEN Xing-rong; ZHANG Jun

    2013-01-01

    Background The degree of pathological microvascular proliferation is an important element in evaluation of the astrocytoma grade.This study was aimed to quantitatively assess the microvascular permeability of brain astrocytoma with the volume transfer constant (Ktrans) and volume of extravascular extracellular space per unit volume of tissue (Ve) from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and to evaluate the effectiveness of the Ktrans and Ve in the grading of astrocytoma.Methods The highest values of the Ktrans and Ve of 67 patients with astrocytoma (27 with grade Ⅱ,12 with grade Ⅲ,and 28 with grade Ⅳ) were obtained.The comparisons of the differences of the Ktrans and Ve between the different grades were conducted using the Mann-Whitney rank-sum tests.Spearman's rank correlation coefficients were determined between Ktrans values,Ve values and astrocytoma grades.Receiver operating characteristic (ROC) curve analyses were performed to determine the cut-off values for the Ktrans and Ve to distinguish between the different grades of astrocytoma.Results There were significant differences (P<0.001) between the different grades in the Ktrans values and Ve values,except for grades Ⅲ and Ⅳ.The Ktrans values and Ve values were both correlated with astrocytoma grades (both P<0.001).The ROC curve analyses showed that the cut-off values for the Ktrans and Ve provided the best combination of sensitivity and specificity in distinguishing between grade Ⅱ and grade Ⅲ or Ⅳ astrocytomas.Conclusions DCE-MRI can play an important role in assessing the microvascular permeability and the grading of brain astrocytoma.

  17. Microwave and magnetic (M2 proteomics of a mouse model of mild traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Teresa M. Evans

    2014-06-01

    Full Text Available Short-term increases in oxidative stress and decreases in motor function, including debilitating effects on balance and motor control, can occur following primary mild traumatic brain injuries (mTBI. However, the long-term effects on motor unit impairment and integrity as well as the molecular mechanisms underlying secondary injuries are poorly understood. We hypothesized that changes in central nervous system-specific protein (CSP expression might correlate to these long-term effects. To test our hypothesis, we longitudinally assessed a closed-skull mTBI mouse model, vs. sham control, at 1, 7, 30, and 120 days post-injury. Motor impairment was determined by rotarod and grip strength performance measures, while motor unit integrity was determined using electromyography. Relative protein expression was determined by microwave and magnetic (M2 proteomics of ipsilateral brain tissue, as previously described. Isoprostane measurements were performed to confirm a primary oxidative stress response. Decoding the relative expression of 476 ± 56 top-ranked proteins for each specimen revealed statistically significant changes in the expression of two well-known CSPs at 1, 7 and 30 days post-injury: P < 0.001 for myelin basic protein (MBP and p < 0.05 for myelin associated glycoprotein (MAG. This was confirmed by Western blot. Moreover, MAG, αII-spectrin (SPNA2 and neurofilament light (NEFL expression at 30 days post-injury were directly related to grip strength (p < 0.05. While higher-powered studies of larger cohorts merit further investigation, this study supports the proof-of-concept that M2 proteomics is a rapid method to quantify putative protein biomarkers and therapeutic targets of mTBI and suggests the feasibility of CSP expression correlations to long-term effects on motor impairment.

  18. Late-Onset Neurodegeneration with Brain Iron Accumulation with Diffusion Tensor Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Syed Omar Shah

    2012-12-01

    Full Text Available Introduction: Neuroferritinopathy is an autosomal dominant neurodegenerative disorder that includes a movement disorder, cognitive decline, and characteristic findings on brain magnetic resonance imaging (MRI due to abnormal iron deposition. Here, we present a late-onset case, along with diffusion tensor imaging (DTI. Case Presentation: We report the case of a 74-year-old Caucasian female with no significant past medical history who presented for evaluation of orofacial dyskinesia, suspected to be edentulous dyskinesia given her history of ill-fitting dentures. She had also developed slowly progressive dysarthria, dysphagia, visual hallucinations as well as stereotypic movements of her hands and feet. Results: The eye-of-the-tiger sign was demonstrated on T2 MRI. Increased fractional anisotropy and T2 hypointensity were observed in the periphery of the globus pallidus, putamen, substantia nigra, and dentate nucleus. T2 hyperintensity was present in the medial dentate nucleus and central globus pallidus. Discussion: The pallidal MRI findings were more typical of pantothenate kinase-associated neurodegeneration (PKAN, but given additional dentate and putamenal involvement, lack of retinopathy, and advanced age of onset, PKAN was less likely. Although the patient’s ferritin levels were within low normal range, her clinical and imaging features led to a diagnosis of neuroferritinopathy. Conclusion: Neurodegeneration with brain iron accumulation (NBIA is a rare cause of orofacial dyskinesia. DTI MRI can confirm abnormal iron deposition. The location of abnormal iron deposits helps in differentiating NBIA subtypes. Degeneration of the dentate and globus pallidus may occur via an analogous process given their similar T2 and DTI MRI appearance.

  19. Brain Basics

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    Full Text Available ... all. She was happily married and successful in business. Then, after a serious setback at work, she ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ...

  20. Brain Basics

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    Full Text Available ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ... depression experience when starting treatment. Gene Studies Advanced technologies are also making it faster, easier, and more ...

  1. Brain Basics

    Medline Plus

    Full Text Available ... and epigenetic changes can be passed on to future generations. Further understanding of genes and epigenetics may ... than ever before. Brain Imaging Using brain imaging technologies such as magnetic resonance imaging (MRI), which uses ...

  2. Quadrupole magnetic mapping of the high resolution spectrometers of Thomas Jefferson National Accelerator Laboratory, Hall A. (Q.M.M. project: Quadrupole Magnetic Measurement)

    International Nuclear Information System (INIS)

    This thesis describes the magnetic measurements that have been performed on the superconducting quadrupoles of the High Resolution Spectrometers of TJNAF, Hall A (USA), which are designed to measure particle momentum up to 4 GeV.c-1 with a σp/p = 10-4 resolution. The mapping method is based on rotating coil technique, the originality being a segmentation of the probe along the quad axis. Together with an accurate magnet modelling, the measurement of the flux variations through the set of rotating coils allows to determine the magnetic field at each point. We use the 3D field formalism, i.e., the Fourier-Bessel expansion of the field obtained by solving the Laplace equation. We describe the QMM method and then the apparatus consisting in two probes of length 1.6 m and 3.2 m built to map the three quadrupoles Q1, Q2, Q3. Data processing uses Fourier analysis. The mapping of the Electron Arm took place in situ in 1996. A first set of results concerns integral measurements including the properties of excitation cycle of the magnets (saturation and hysteresis). Second set of results in terms of local field yields the 3D field maps of the quadrupoles. After having applied corrections to the data we obtain a local field accuracy of 5 Gauss on each component, i.e. an uncertainty of 5.10-4 relative to the quadrupole central field. We use SNAKE ray-tracing code with the implementation of QMM field maps and obtain preliminary results on HRS optics. (author)

  3. Brain magnetic resonance imaging, aerobic power, and metabolic parameters among 30 asymptomatic scuba divers.

    Science.gov (United States)

    Tripodi, D; Dupas, B; Potiron, M; Louvet, S; Geraut, C

    2004-11-01

    The aim of the study was to evaluate the presence of cerebral lesions in asymptomatic scuba divers and explain the causes of them: potential risk factors associating cardiovascular risk factors, low aerobic capacity, or characteristics of diving (maximum depth, ascent rate). Experienced scuba divers, over 40 years of age, without any decompression sickness (DCS) history were included. We studied 30 scuba divers (instructors) without any clinical symptoms. For all of them, we carried out a clinical examination with fatty body mass determination and we questioned them about their diving habits. A brain Magnetic Resonance imaging (MRI), an assessment of maximal oxygen uptake, glycemia, triglyceridemia, and cholesterolemia were systematically carried out. Cerebral spots of high intensity were found at 33 % in the scuba diving group and 30 % in the control group. In the diving group, abnormalities were related to unsafe scuba-diving or metabolic abnormalities. In our study, we did not find a significant relationship between the lesions of the central nervous system, and the age, depth of the dives, number of dives, and ergometric performances (maximal oxygen uptake, V.O (2max), serum level of blood lactate). Nevertheless, we found a significant relationship between the lesions of the central nervous system and ascent rate faster than 10 meters per minute (r = 0.57; p = 0.003) or presence of high level of cholesterolemia (r = 0.6; p = 0.001). We found concordant results using the Cochran's Test: meaningful link between the number of brain lesions and the speed of decompression (Uexp = 14 < Utable = 43; alpha = 0.05, p < 0.01). We concluded that hyperintensities can be explained by preformed nitrogen gas microbubbles and particularly in presence of cholesterol, when the ascent rate is up to 10 meters per minute. So, it was remarkable to note that asymptomatic patients practicing scuba diving either professionally or recreationally, presented lesions of the central nervous

  4. High Resolution Nuclear Magnetic Resonance Studies of the Active Site of Chymotrypsin. I. The Hydrogen Bonded Protons of the “Charge Relay” System

    NARCIS (Netherlands)

    Robillard, G.; Shulman, R.G.

    1974-01-01

    High resolution proton nuclear magnetic resonance has been used to observe protons at the active site of chymotrypsin Aδ and at the same region of chymotrypsinogen A. A single resonance with the intensity of one proton is located in the low field region of the nuclear magnetic resonance spectrum. Th

  5. High-Resolution Magnetic Resonance Imaging of Trabecular Bone in the Wrist at 3 Tesla: Initial Results

    Energy Technology Data Exchange (ETDEWEB)

    Ludescher, B.; Martirosian, P.; Lenk, S.; Machann, J.; Dammann, F.; Schick, F.; Claussen, C.; Schlemmer, H. [Univ. Clinic, Tuebingen (Germany). Dept. of Diagnostic Radiology and Section on Experimental Radiology

    2005-05-01

    Purpose: To evaluate the feasibility of high-resolution magnetic resonance imaging (MRI) of trabecular bone of the wrist at 3 Tesla (3T) in vivo and to assess the potential benefit of the increased resolution for clinical assessment of structural changes in spongy bone. Material and Methods: High-resolution MRI of the wrist was performed with a whole-body 3T MR scanner using a dedicated circularly polarized transmit/receive wrist-coil. Two 3D-FISP sequences with a spatial resolution of 300x300x300 {mu}m{sup 3} in a measuring time of TA{approx}7:51 min, and 200x200x200 {mu}m{sup 3} in TA{approx}9:33 min were applied. Seven young healthy volunteers and three elderly subjects with suspected osteoporosis were examined. The signal-to-noise ratio (SNR) in the optimized setup at 3T was compared to measurements at 1.5T. Results: The images at 3T allow microscopic analysis of the bone structure at an isotropic spatial resolution of 200 {mu}m in examination times of <10 min. Differences in the structure of the spongy bone between normal and markedly osteoporotic subjects are well depicted. The SNR at 3T was found up to 16 times higher than at 1.5T applying unchanged imaging parameters. Conclusion: The proposed high-resolution MRI technique offers high potential in the diagnosis and follow-up of diseases with impaired bone structure of hand and/or wrist in clinical applications.

  6. Activation changes in zebra finch (Taeniopygia guttata brain areas evoked by alterations of the earth magnetic field.

    Directory of Open Access Journals (Sweden)

    Nina Keary

    Full Text Available Many animals are able to perceive the earth magnetic field and to use it for orientation and navigation within the environment. The mechanisms underlying the perception and processing of magnetic field information within the brain have been thoroughly studied, especially in birds, but are still obscure. Three hypotheses are currently discussed, dealing with ferromagnetic particles in the beak of birds, with the same sort of particles within the lagena organs, or describing magnetically influenced radical-pair processes within retinal photopigments. Each hypothesis is related to a well-known sensory organ and claims parallel processing of magnetic field information with somatosensory, vestibular and visual input, respectively. Changes in activation within nuclei of the respective sensory systems have been shown previously. Most of these previous experiments employed intensity enhanced magnetic stimuli or lesions. We here exposed unrestrained zebra finches to either a stationary or a rotating magnetic field of the local intensity and inclination. C-Fos was used as an activity marker to examine whether the two treatments led to differences in fourteen brain areas including nuclei of the somatosensory, vestibular and visual system. An ANOVA revealed an overall effect of treatment, indicating that the magnetic field change was perceived by the birds. While the differences were too small to be significant in most areas, a significant enhancement of activation by the rotating stimulus was found in a hippocampal subdivision. Part of the hyperpallium showed a strong, nearly significant, increase. Our results are compatible with previous studies demonstrating an involvement of at least three different sensory systems in earth magnetic field perception and suggest that these systems, probably less elaborated, may also be found in nonmigrating birds.

  7. A streak camera based fiber optic pulsed polarimetry technique for magnetic sensing to sub-mm resolution

    Science.gov (United States)

    Smith, R. J.; Weber, T. E.

    2016-11-01

    The technique of fiber optic pulsed polarimetry, which provides a distributed (local) measurement of the magnetic field along an optical fiber, has been improved to the point where, for the first time, photocathode based optical detection of backscatter is possible with sub-mm spatial resolutions. This has been realized through the writing of an array of deterministic fiber Bragg gratings along the fiber, a so-called backscatter-tailored optical fiber, producing a 34 000-fold increase in backscatter levels over Rayleigh. With such high backscatter levels, high repetition rate lasers are now sufficiently bright to allow near continuous field sensing in both space and time with field resolutions as low as 0.005 T and as high as 170 T over a ˜mm interval given available fiber materials.

  8. Role of magnetic field strength and numerical resolution in simulations of the heat-flux driven buoyancy instability

    CERN Document Server

    Avara, Mark J; Bogdanović, Tamara

    2013-01-01

    The role played by magnetic fields in the intracluster medium (ICM) of galaxy clusters is complex. The weakly collisional nature of the ICM leads to thermal conduction that is channelled along field lines. This anisotropic heat conduction profoundly changes the stability of the ICM atmosphere, with convective stabilities being driven by temperature gradients of either sign. Here, we employ the Athena magnetohydrodynamic code to investigate the local non-linear behavior of the heat-flux driven buoyancy instability (HBI), relevant in the cores of cooling-core clusters where the temperature increases with radius. We study a grid of 2-d simulations that span a large range of initial magnetic field strengths and numerical resolutions. For very weak initial fields, we recover the previously known result that the HBI wraps the field in the horizontal direction thereby shutting off the heat flux. However, we find that simulations which begin with intermediate initial field strengths have a qualitatively different beh...

  9. qPlus Magnetic Force Microscopy in Frequency-Modulation Mode with milli-Hertz Resolution

    CERN Document Server

    Schneiderbauer, M

    2011-01-01

    Magnetic force microscopy (MFM) allows one to image the domain structure of ferromagnetic samples by probing the dipole forces between a magnetic probe tip and a magnetic sample. The magnetic domain structure of the sample depends on the atomic arrangement of individual electron spins. It is desirable to be able to image both individual atoms and domain structures with a single probe. However, the force gradients of the interactions responsible for atomic contrast and those causing domain contrast are orders of magnitude apart - ranging from up to 100N/m for atomic interactions down to 0.0001N/m for magnetic dipole interactions. Here, we show that this gap can be bridged with a qPlus sensor, with a stiffness of 1800N/m (optimized for atomic interaction), that is sensitive enough to measure milli-Hertz frequency contrast caused by magnetic dipole-dipole interactions. Thus we have succeeded to establish a sensing technique that performs Scanning Tunneling Microscopy, Atomic Force Microscopy and MFM with a singl...

  10. High Resolution Magic Angle Spinning 1H-NMR Metabolic Profiling of Nanoliter Biological Tissues at High Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ju; Hu, Jian Z.; Burton, Sarah D.; Hoyt, David W.

    2013-03-05

    It is demonstrated that a high resolution magic angle spinning 1H-NMR spectrum of biological tissue samples with volumes as small as 150 nanoliters, or 0.15 mg in weight, can be acquired in a few minutes at 21.1 T magnetic field using a commercial 1.6 mm fast-MAS probe with minor modification of the MAS rotor. The strategies of sealing the samples inside the MAS rotor to avoid fluid leakage as well as the ways of optimizing the signal to noise are discussed.

  11. Magnetic resonance imaging structural alterations in brain of alcohol abusers and its association with impulsivity.

    Science.gov (United States)

    Asensio, Samuel; Morales, Julia L; Senabre, Isabel; Romero, Maria J; Beltran, Miguel A; Flores-Bellver, Miguel; Barcia, Jorge M; Romero, Francisco J

    2016-07-01

    Despite the suggestion that impulsivity plays a central role in the transfer from a recreational drug use to a substance use disorder, very few studies focused on neurobiological markers for addiction. This study aimed to identify volumetric alterations in a sample of patients with mild alcohol use disorder with a short history of alcohol use, compared with a control group, and also focused on its association with impulsivity levels. Most magnetic resonance imaging studies have focused on severe alcohol use disorder, formerly called alcohol-dependent patients, showing alcohol-related structural alterations and their association with alcohol use history variables but not with personality parameters like impulsivity. Our hypothesis is that our group of alcohol users may already display structural alterations especially in brain regions related to inhibitory control like medial-prefrontal regions, and that those structural alterations could be more associated to personality traits like impulsivity than to drug use variables. Our results clearly demonstrate that our population showed lower regional grey and white matter volumes in the medial-prefrontal and orbitofrontal cortices, as well as higher regional white matter volume in the ventral striatum and the internal capsule. Volumetric alterations were associated to the Barratt's impulsivity score: the more impulsive the subjects, the lower the medial-prefrontal cortex grey matter volume. PMID:25988724

  12. Comparing implementations of magnetic-resonance-guided fluorescence molecular tomography for diagnostic classification of brain tumors

    Science.gov (United States)

    Davis, Scott C.; Samkoe, Kimberley S.; O'Hara, Julia A.; Gibbs-Strauss, Summer L.; Paulsen, Keith D.; Pogue, Brian W.

    2010-09-01

    Fluorescence molecular tomography (FMT) systems coupled to conventional imaging modalities such as magnetic resonance imaging (MRI) and computed tomography provide unique opportunities to combine data sets and improve image quality and content. Yet, the ideal approach to combine these complementary data is still not obvious. This preclinical study compares several methods for incorporating MRI spatial prior information into FMT imaging algorithms in the context of in vivo tissue diagnosis. Populations of mice inoculated with brain tumors that expressed either high or low levels of epidermal growth factor receptor (EGFR) were imaged using an EGF-bound near-infrared dye and a spectrometer-based MRI-FMT scanner. All data were spectrally unmixed to extract the dye fluorescence from the tissue autofluorescence. Methods to combine the two data sets were compared using student's t-tests and receiver operating characteristic analysis. Bulk fluorescence measurements that made up the optical imaging data set were also considered in the comparison. While most techniques were able to distinguish EGFR(+) tumors from EGFR(-) tumors and control animals, with area-under-the-curve values=1, only a handful were able to distinguish EGFR(-) tumors from controls. Bulk fluorescence spectroscopy techniques performed as well as most imaging techniques, suggesting that complex imaging algorithms may be unnecessary to diagnose EGFR status in these tissue volumes.

  13. Caveat of measuring perfusion indexes using intravoxel incoherent motion magnetic resonance imaging in the human brain

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wen-Chau [National Taiwan University, Graduate Institute of Oncology, Taipei (China); National Taiwan University, Graduate Institute of Clinical Medicine, Taipei (China); National Taiwan University, Graduate Institute of Biomedical Electronics and Bioinformatics, Taipei (China); National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Chen, Ya-Fang; Yang, Shun-Chung; My, Pei-Chi [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Tseng, Han-Min [National Taiwan University Hospital, Department of Neurology, Taipei (China)

    2015-08-15

    To numerically and experimentally investigate the robustness of intravoxel incoherent motion (IVIM) magnetic resonance imaging in measuring perfusion indexes in the human brain. Eighteen healthy volunteers were imaged on a 3 T clinical system. Data of IVIM imaging (12 b-values ranging from 0 to 1000 s/mm{sup 2}, 12 repetitions) were fitted with a bi-exponential model to extract blood volume fraction (f) and pseudo-diffusion coefficient (D*). The robustness of measurement was assessed by bootstrapping. Dynamic susceptibility contrast (DSC) imaging and arterial spin-labelling (ASL) imaging were performed for cross-modal comparison. Numerical simulations were performed to assess the accuracy and precision of f and D* estimates at varied signal-to-noise ratio (SNR{sub b1000}). Based on our experimental setting (SNR{sub b1000} ∝ 30), the average error/variability is ∝ 5 %/25 % for f and ∝ 100 %/30 % for D* in gray matter, and ∝ 10 %/50 % for f and ∝ 300 %/60 % for D* in white matter. Correlation was found between f and DSC-derived cerebral blood volume in gray matter (r = 0.29 - 0.48 across subjects, p < 10{sup -5}), but not in white matter. No correlation was found between f-D* product and ASL-derived cerebral blood flow. f may provide noninvasive measurement of cerebral blood volume, particularly in gray matter. D* has limited robustness and should be interpreted with caution. (orig.)

  14. A longitudinal magnetic resonance elastography study of murine brain tumors following radiation therapy

    Science.gov (United States)

    Feng, Y.; Clayton, E. H.; Okamoto, R. J.; Engelbach, J.; Bayly, P. V.; Garbow, J. R.

    2016-08-01

    An accurate and noninvasive method for assessing treatment response following radiotherapy is needed for both treatment monitoring and planning. Measurement of solid tumor volume alone is not sufficient for reliable early detection of therapeutic response, since changes in physiological and/or biomechanical properties can precede tumor volume change following therapy. In this study, we use magnetic resonance elastography to evaluate the treatment effect after radiotherapy in a murine brain tumor model. Shear modulus was calculated and compared between the delineated tumor region of interest (ROI) and its contralateral, mirrored counterpart. We also compared the shear modulus from both the irradiated and non-irradiated tumor and mirror ROIs longitudinally, sampling four time points spanning 9–19 d post tumor implant. Results showed that the tumor ROI had a lower shear modulus than that of the mirror ROI, independent of radiation. The shear modulus of the tumor ROI decreased over time for both the treated and untreated groups. By contrast, the shear modulus of the mirror ROI appeared to be relatively constant for the treated group, while an increasing trend was observed for the untreated group. The results provide insights into the tumor properties after radiation treatment and demonstrate the potential of using the mechanical properties of the tumor as a biomarker. In future studies, more closely spaced time points will be employed for detailed analysis of the radiation effect.

  15. Cognitive impairment after traumatic brain injury: a functional magnetic resonance imaging study using the Stroop task

    Energy Technology Data Exchange (ETDEWEB)

    Soeda, Akio; Iwama, Toru [Gifu University School of Medicine, Department of Neurosurgery, Gifu City (Japan); Nakashima, Toshihiko; Okumura, Ayumi; Shinoda, Jun [Kizawa Memorial Hospital, Chubu Medical Center for Prolonged Traumatic Brain Dysfunction, Department of Neurosurgery, Minokamo (Japan); Kuwata, Kazuo [Gifu University School of Medicine, Department of Biochemistry and Biophysics, Gifu (Japan)

    2005-07-01

    The anterior cingulate cortex (ACC) plays a key role in cognition, motor function, and emotion processing. However, little is known about how traumatic brain injury (TBI) affects the ACC system. Our purpose was to compare, by functional magnetic resonance imaging (fMRI) studies, the patterns of cortical activation in patients with cognitive impairment after TBI and those of normal subjects. Cortical activation maps of 11 right-handed healthy control subjects and five TBI patients with cognitive impairment were recorded in response to a Stroop task during a block-designed fMRI experiment. Statistical parametric mapping (SPM99) was used for individual subjects and group analysis. In TBI patients and controls, cortical activation, found in similar regions of the frontal, occipital, and parietal lobes, resembled patterns of activation documented in previous neuroimaging studies of the Stroop task in healthy controls. However, the TBI patients showed a relative decrease in ACC activity compared with the controls. Cognitive impairment in TBI patients seems to be associated with alterations in functional cerebral activity, especially less activation of the ACC. These changes are probably the result of destruction of neural networks after diffuse axonal injury and may reflect cortical disinhibition attributable to disconnection or compensation for an inefficient cognitive process. (orig.)

  16. A longitudinal magnetic resonance elastography study of murine brain tumors following radiation therapy

    Science.gov (United States)

    Feng, Y.; Clayton, E. H.; Okamoto, R. J.; Engelbach, J.; Bayly, P. V.; Garbow, J. R.

    2016-08-01

    An accurate and noninvasive method for assessing treatment response following radiotherapy is needed for both treatment monitoring and planning. Measurement of solid tumor volume alone is not sufficient for reliable early detection of therapeutic response, since changes in physiological and/or biomechanical properties can precede tumor volume change following therapy. In this study, we use magnetic resonance elastography to evaluate the treatment effect after radiotherapy in a murine brain tumor model. Shear modulus was calculated and compared between the delineated tumor region of interest (ROI) and its contralateral, mirrored counterpart. We also compared the shear modulus from both the irradiated and non-irradiated tumor and mirror ROIs longitudinally, sampling four time points spanning 9-19 d post tumor implant. Results showed that the tumor ROI had a lower shear modulus than that of the mirror ROI, independent of radiation. The shear modulus of the tumor ROI decreased over time for both the treated and untreated groups. By contrast, the shear modulus of the mirror ROI appeared to be relatively constant for the treated group, while an increasing trend was observed for the untreated group. The results provide insights into the tumor properties after radiation treatment and demonstrate the potential of using the mechanical properties of the tumor as a biomarker. In future studies, more closely spaced time points will be employed for detailed analysis of the radiation effect.

  17. Anatomy and metabolism of the normal human brain studied by magnetic resonance at 1.5 Tesla

    International Nuclear Information System (INIS)

    Proton magnetic resonance (MR) images were obtained of the human head in magnetic fields as high as 1.5 Tesla (T) using slotted resonator high radio-frequency (RF) detection coils. The images showed no RF field penetration problems and exhibited an 11 (+/-1)-fold improvement in signal-to-noise ratio over a .12-T imaging system. The first localized phosphorus 31, carbon 13, and proton MR chemical shift spectra recorded with surface coils from the head and body in the same instrument showed relative concentrations of phosphorus metabolites, triglycerides, and, when correlated with proton images, negligible lipid (-CH2-) signal from brain tissue on the time scale of the imaging experiment. Sugar phosphate and phosphodiester concentrations were significantly elevated in the head compared with muscle. This method should allow the combined assessment of anatomy, metabolism, and biochemistry in both the normal and diseased brain

  18. Human brain imaging

    International Nuclear Information System (INIS)

    Just as there have been dramatic advances in the molecular biology of the human brain in recent years, there also have been remarkable advances in brain imaging. This paper reports on the development and broad application of microscopic imaging techniques which include the autoradiographic localization of receptors and the measurement of glucose utilization by autoradiography. These approaches provide great sensitivity and excellent anatomical resolution in exploring brain organization and function. The first noninvasive external imaging of receptor distributions in the living human brain was achieved by positron emission tomography (PET) scanning. Developments, techniques and applications continue to progress. Magnetic resonance imaging (MRI) is also becoming important. Its initial clinical applications were in examining the structure and anatomy of the brain. However, more recent uses, such as MRI spectroscopy, indicate the feasibility of exploring biochemical pathways in the brain, the metabolism of drugs in the brain, and also of examining some of these procedures at an anatomical resolution which is substantially greater than that obtainable by PET scanning. The issues will be discussed in greater detail

  19. Regional and voxel-wise comparisons of blood flow measurements between dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) and arterial spin labeling (ASL) in brain tumors.

    Science.gov (United States)

    White, Carissa M; Pope, Whitney B; Zaw, Taryar; Qiao, Joe; Naeini, Kourosh M; Lai, Albert; Nghiemphu, Phioanh L; Wang, J J; Cloughesy, Timothy F; Ellingson, Benjamin M

    2014-01-01

    The objective of the current study was to evaluate the regional and voxel-wise correlation between dynamic susceptibility contrast (DSC) and arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) measurement of cerebral blood flow (CBF) in patients with brain tumors. Thirty patients with histologically verified brain tumors were evaluated in the current study. DSC-MRI was performed by first using a preload dose of gadolinium contrast, then collecting a dynamic image acquisition during a bolus of contrast, followed by posthoc contrast agent leakage correction. Pseudocontinuous ASL was collected using 30 pairs of tag and control acquisition using a 3-dimensional gradient-echo spin-echo (GRASE) acquisition. All images were registered to a high-resolution anatomical atlas. Average CBF measurements within regions of contrast-enhancement and T2 hyperintensity were evaluated between the two modalities. Additionally, voxel-wise correlation between CBF measurements obtained with DSC and ASL were assessed. Results demonstrated a positive linear correlation between DSC and ASL measurements of CBF when regional average values were compared; however, a statistically significant voxel-wise correlation was only observed in around 30-40% of patients. These results suggest DSC and ASL may provide regionally similar, but spatially different measurements of CBF.

  20. Local high-resolution crustal magnetic field analysis from satellite data

    Science.gov (United States)

    Plattner, Alain; Simons, Frederik J.

    2016-04-01

    Planetary crustal magnetic fields are key to understanding a planet or moon's structure and history. Due to satellite orbit parameters such as aerobraking (Mars) or only partial coverage (Mercury), or simply because of the strongly heterogeneous crustal field strength, satellite data of planetary magnetic fields vary regionally in their signal-to noise ratio and data coverage. To take full advantage of data quality within one region of a planet or moon without diluting the data with lower quality measurements outside of that region we resort to local methods. Slepian functions are linear combinations of spherical harmonics that provide local sensitivity to structure. Here we present a selection of crustal magnetic field models obtained from vector-valued variable-altitude satellite observations using an altitude-cognizant gradient-vector Slepian approach. This method is based on locally maximizing energy concentration within the region of data availability while simultaneously bandlimiting the model in terms of its spherical-harmonic degree and minimizing noise amplification due to downward continuation. For simple regions such as spherical caps, our method is computationally efficient and allows us to calculate local crustal magnetic field solutions beyond spherical harmonic degree 800, if the data permit. We furthermore discuss extensions of the method that are optimized for the analysis and separation of internal and external magnetic fields.

  1. Towards ultra-high resolution fibre tract mapping of the human brain - registration of polarised light images and reorientation of fibre vectors

    Directory of Open Access Journals (Sweden)

    Christoph Palm

    2010-04-01

    Full Text Available Polarised Light Imaging (PLI utilises the birefringence of the myelin sheaths in order to visualise the orientation of nerve fibres in microtome sections of adult human post-mortem brains at ultra-high spatial resolution. The preparation of post-mortem brains for PLI involves fixation, freezing and cutting into 100-micrometer thick sections. Hence, geometrical distortions of histological sections are inevitable and have to be removed for 3D reconstruction and subsequent fibre tracking. We here present a processing pipeline for 3D reconstruction of these sections using PLI derived multimodal images of post-mortem brains. Blockface images of the brains were obtained during cutting; they serve as reference data for alignment and elimination of distortion artefacts. In addition to the spatial image transformation, fibre orientation vectors were reoriented using the transformation fields, which consider both affine and subsequent non-linear registration. The application of this registration and reorientation approach results in a smooth fibre vector field, which reflects brain morphology. PLI combined with 3D reconstruction and fibre tracking is a powerful tool for human brain mapping. It can also serve as an independent method for evaluating in vivo fibre tractography.

  2. Brain regions involved in moxibustion-induced analgesia in irritable bowel syndrome with diarrhea: a functional magnetic resonance imaging study

    OpenAIRE

    Zhu, Yi; Wu, Zhiyuan; Ma, Xiaopeng; Liu, Huirong; Bao, Chunhui; YANG, LING; Cui, Yunhua; Zhou, Cili; Wang, Xiaomei; Wang, Yuemin; Zhang, Zhongwei; Zhang, Huan; Jia, Haipeng; Wu, Huangan

    2014-01-01

    Background Moxibustion is one of the most commonly used therapies in acupuncture practice, and is demonstrated to be beneficial for patients with diarrhea from irritable bowel syndrome (D-IBS). But its mechanism remains unclear. Because visceral hypersensitivity in IBS patients has been documented by evaluation of perceived stimulations through functional magnetic resonance imaging (fMRI) studies, we focused on observing brain imaging changes in D-IBS patients during rectal balloon distention...

  3. Improving the specificity of R2' to the deoxyhaemoglobin content of brain tissue: Prospective correction of macroscopic magnetic field gradients

    OpenAIRE

    Blockley, NP; Stone, AJ

    2016-01-01

    The reversible transverse relaxation rate, R2', is sensitive to the deoxyhaemoglobin content of brain tissue, enabling information about the oxygen extraction fraction to be obtained. However, R2' is also sensitive to macroscopic magnetic field gradients, particularly at air-tissue interfaces where a large susceptibility difference is present. It is important that this latter effect is minimised in order to produce meaningful estimates of blood oxygenation. Therefore, the aim of this study wa...

  4. Gender differences in functional hemispheric asymmetry during processing of vowels as reflected by the human brain magnetic response

    OpenAIRE

    Obleser, Jonas; Eulitz, Carsten; Lahiri, Aditi; Elbert, Thomas

    2001-01-01

    A number of findings indicate gender differences in language-related functional hemispheric brain asymmetry. To test if such gender-specific laterality is already present at the level of vowel-processing, the auditory evoked magnetic field was recorded in healthy right-handed male and female participants in response to the German synthetic vowels [a], [e] and [i]. Female participants exhibited stronger N100m responses than male participants over the left hemisphere. This observation was highl...

  5. Real-time functional magnetic imaging-brain-computer interface and virtual reality promising tools for the treatment of pedophilia.

    Science.gov (United States)

    Renaud, Patrice; Joyal, Christian; Stoleru, Serge; Goyette, Mathieu; Weiskopf, Nikolaus; Birbaumer, Niels

    2011-01-01

    This chapter proposes a prospective view on using a real-time functional magnetic imaging (rt-fMRI) brain-computer interface (BCI) application as a new treatment for pedophilia. Neurofeedback mediated by interactive virtual stimuli is presented as the key process in this new BCI application. Results on the diagnostic discriminant power of virtual characters depicting sexual stimuli relevant to pedophilia are given. Finally, practical and ethical implications are briefly addressed.

  6. THE STUDY OF THE BRAIN IN A PATIENT WITH TYPE 1 DIABETES MELLITUS USING TECHNIQUES OF MAGNETIC RESONANCE IMAGING

    OpenAIRE

    Yu. G. Samoylova; N. G. Zhukova; M. V. Matveyeva; M. A. Rotkank; O. S. Tonkikh

    2015-01-01

    Type 1 diabetes mellitus (T1DM) is now widely distributed worldwide and in theRussian Federation, it is an important medical and social problem in connection with the development of serious, disabling complications. Some of these complications could make changes in the brain which are accompanied by cognitive impairments that decrease quality of life and worsening disease compensation. The diagnosis of these disorders to date, possible by using modern methods of magnetic resonance imaging, wh...

  7. Is it Possible to Extract Brain Metabolic Pathways Information from In Vivo H Nuclear Magnetic Resonance Spectroscopy Data?

    CERN Document Server

    de Lara, Alejandro Chinea Manrique

    2010-01-01

    In vivo H nuclear magnetic resonance (NMR) spectroscopy is an important tool for performing non-invasive quantitative assessments of brain tumour glucose metabolism. Brain tumours are considered as fast-growth tumours because of their high rate of proliferation. In addition, tumour cells exhibit profound genetic, biochemical and histological differences with respect to the original non-transformed cellular types. Therefore, there is a strong interest from the clinical investigator point of view in understanding the role of brain metabolites in normal and pathological conditions and especially on the development of early tumour detection techniques. Unfortunately, current diagnosis techniques ignore the dynamic aspects of these signals. It is largely believed that temporal variations of NMR Spectra are noisy or just simply do not carry enough information to be exploited by any reliable diagnosis procedure. Thus, current diagnosis procedures are mainly based on empirical observations extracted from single avera...

  8. An in vivo three-dimensional magnetic resonance imaging-based averaged brain collection of the neonatal piglet (Sus scrofa.

    Directory of Open Access Journals (Sweden)

    Matthew S Conrad

    Full Text Available Due to the fact that morphology and perinatal growth of the piglet brain is similar to humans, use of the piglet as a translational animal model for neurodevelopmental studies is increasing. Magnetic resonance imaging (MRI can be a powerful tool to study neurodevelopment in piglets, but many of the MRI resources have been produced for adult humans. Here, we present an average in vivo MRI-based atlas specific for the 4-week-old piglet. In addition, we have developed probabilistic tissue classification maps. These tools can be used with brain mapping software packages (e.g. SPM and FSL to aid in voxel-based morphometry and image analysis techniques. The atlas enables efficient study of neurodevelopment in a highly tractable translational animal with brain growth and development similar to humans.

  9. An in vivo three-dimensional magnetic resonance imaging-based averaged brain collection of the neonatal piglet (Sus scrofa).

    Science.gov (United States)

    Conrad, Matthew S; Sutton, Bradley P; Dilger, Ryan N; Johnson, Rodney W

    2014-01-01

    Due to the fact that morphology and perinatal growth of the piglet brain is similar to humans, use of the piglet as a translational animal model for neurodevelopmental studies is increasing. Magnetic resonance imaging (MRI) can be a powerful tool to study neurodevelopment in piglets, but many of the MRI resources have been produced for adult humans. Here, we present an average in vivo MRI-based atlas specific for the 4-week-old piglet. In addition, we have developed probabilistic tissue classification maps. These tools can be used with brain mapping software packages (e.g. SPM and FSL) to aid in voxel-based morphometry and image analysis techniques. The atlas enables efficient study of neurodevelopment in a highly tractable translational animal with brain growth and development similar to humans.

  10. Magnetic resonance imaging-guided attenuation and scatter corrections in three-dimensional brain positron emission tomography

    CERN Document Server

    Zaidi, H; Slosman, D O

    2003-01-01

    Reliable attenuation correction represents an essential component of the long chain of modules required for the reconstruction of artifact-free, quantitative brain positron emission tomography (PET) images. In this work we demonstrate the proof of principle of segmented magnetic resonance imaging (MRI)-guided attenuation and scatter corrections in 3D brain PET. We have developed a method for attenuation correction based on registered T1-weighted MRI, eliminating the need of an additional transmission (TX) scan. The MR images were realigned to preliminary reconstructions of PET data using an automatic algorithm and then segmented by means of a fuzzy clustering technique which identifies tissues of significantly different density and composition. The voxels belonging to different regions were classified into air, skull, brain tissue and nasal sinuses. These voxels were then assigned theoretical tissue-dependent attenuation coefficients as reported in the ICRU 44 report followed by Gaussian smoothing and additio...

  11. Magnetic resonance imaging features of brain and spinal cord injury in a fatal case of isopropanol intoxication

    Directory of Open Access Journals (Sweden)

    Mahajan PS

    2014-03-01

    Full Text Available Parag Suresh Mahajan,1 Joyal Jacob Mathew,2 Abhilash Pulincherry Jayaram,1 Vidya Chander Negi,1 Mohamed Milad Abu Hmaira21Department of Radiology, 2Department of Medicine, Al-Khor Hospital, Hamad Medical Corporation, Doha, QatarAbstract: A 60-year-old man presented with headache, dizziness, and disorientation one day after consumption of isopropanol along with ethanol. Computed tomography (CT of the brain performed immediately was unremarkable. The patient collapsed within the hospital 30 minutes after the CT scan was done, and remained comatose until death, showing no improvement with symptomatic treatment. Magnetic resonance imaging of the brain and spine done 6 days after admission revealed bilaterally symmetrical hyperintensities involving the cerebral and cerebellar cortex and white matter, basal ganglia, thalami, and brainstem on T2-weighted, fluid attenuated inversion recovery and diffusion weighted images; similar hyperintensities were seen involving the swollen and edematous cervical spinal cord and cerebellar tonsillar herniation compressing the proximal cervical cord. Petechial hemorrhages were also noted within the brainstem. These features are compatible with toxic injury to the brain and cervical spinal cord. To our knowledge, the magnetic resonance imaging features of brain and spinal cord injury and cerebellar tonsillar herniation, secondary to isopropanol intoxication have not been reported in the published literature before.Keywords: alcohol intoxication, computed tomography, isopropyl alcohol, ethyl alcohol, toxicity

  12. Maintenance of high-energy brain phosphorous compounds during insulin-induced hypoglycemia in men. 31P nuclear magnetic resonance spectroscopy study

    DEFF Research Database (Denmark)

    Hilsted, Jannik; Jensen, K E; Thomsen, C;

    1988-01-01

    31P nuclear magnetic resonance (NMR) spectroscopy allows noninvasive studies of cerebral energy-rich phosphorous compounds in humans. In an attempt to characterize the relationship between peripheral blood glucose concentrations and whole-brain phosphate metabolism during insulin...

  13. MAGNETIC-RESONANCE-IMAGING OF THE BRAIN AND NEUROPSYCHOLOGICAL EVALUATION IN CHILDREN TREATED FOR ACUTE LYMPHOBLASTIC-LEUKEMIA AT A YOUNG AGE

    NARCIS (Netherlands)

    KINGMA, A; MOOYAART, EL; KAMPS, WA; WILMINK, JT

    1993-01-01

    Purpose: To evaluate the adverse late effects of ALL treatment on cognitive functions and brain morphology; to integrate the results of a neuropsychological and neuroradiological study. Patients and Methods: Cranial magnetic resonance imaging (MRI) and neuropsychological assessments (NA) were perfor

  14. High-resolution AUV-based near bottom magnetic surveys at Palinuro volcanic complex (Southern Tyrrhenian Sea)

    Science.gov (United States)

    Cocchi, L.; Plunkett, S.; Augustin, N.; Petersen, S.

    2013-12-01

    In this paper we present the preliminary results of new near bottom magnetic datasets collected during the recent POS442 cruise using the autonomous underwater vehicle (AUV) Abyss. The Southern Tyrrhenian basin is characterized by deep seafloor interspersed with huge volcanic seamounts (e.g Vavilov and Marsili and those associated to the Aeolian volcanic arc), which were formed during eastward roll back of the Apennine subduction system. These submarine edifices often are affected by significant hydrothermal activity and associated mineral deposits such as those observed at Marsili, Palinuro and Panarea. The western part of the Palinuro volcanic complex is characterized by a half rim of a caldera-like structure and hosts hydrothermal barite-pyrite deposits. Until recently, the full extent of the hydrothermal system remained poorly defined, as exploration has been limited to a few specific sites. In November 2012, a set of high resolution near seafloor geophysical surveys were carried out using GEOMAR's AUV Abyss to attempt to better define the hydrothermal mineralization at Palinuro. Five AUV dives were performed, mapping a total area of 3.7 km2 over the western part of Palinuro. Geomar's Abyss AUV (a Remus6000 class vehicle) was equipped with an Applied Physics Systems flux gate magnetometer, writing to a stand alone data logger, powered by the AUV's main batteries. The 5 dives were performed within the same area but with different primary geophysical sensors (multibeam, sidescan sonar, subbottom profiler), survey altitudes above seafloor (100m, 40m) and line spacing (150m, 100m, 20m). Magnetic data was collect on all five dives. At the beginning of each dive, the AUV performed a set of calibration manoeuvres, involving a 360 degree heading variation, a set of three upwards/downwards pitches, and three port and starboard yaws. This magnetic data reveals the magnetization features of the seafloor in unprecedented detail, highlighting a complex pattern mostly due to

  15. Pattern recognition analysis of proton nuclear magnetic resonance spectra of brain tissue extracts from rats anesthetized with propofol or isoflurane.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kawaguchi

    Full Text Available BACKGROUND: General anesthesia is routinely used as a surgical procedure and its safety has been endorsed by clinical outcomes; however, its effects at the molecular level have not been elucidated. General anesthetics influence glucose metabolism in the brain. However, the effects of anesthetics on brain metabolites other than those related to glucose have not been well characterized. We used a pattern recognition analysis of proton nuclear magnetic resonance spectra to visualize the changes in holistic brain metabolic phenotypes in response to the widely used intravenous anesthetic propofol and the volatile anesthetic isoflurane. METHODOLOGY/PRINCIPAL FINDINGS: Rats were randomized into five groups (n = 7 each group. Propofol and isoflurane were administered to two groups each, for 2 or 6 h. The control group received no anesthesia. Brains were removed directly after anesthesia. Hydrophilic compounds were extracted from excised whole brains and measured by proton nuclear magnetic resonance spectroscopy. All spectral data were processed and analyzed by principal component analysis for comparison of the metabolite profiles. Data were visualized by plotting principal component (PC scores. In the plots, each point represents an individual sample. The propofol and isoflurane groups were clustered separately on the plots, and this separation was especially pronounced when comparing the 6-h groups. The PC scores of the propofol group were clearly distinct from those of the control group, particularly in the 6-h group, whereas the difference in PC scores was more subtle in the isoflurane group and control groups. CONCLUSIONS/SIGNIFICANCE: The results of the present study showed that propofol and isoflurane exerted differential effects on holistic brain metabolism under anesthesia.

  16. The resolution of a magnetic anomaly map expected from GRM data

    Science.gov (United States)

    Strangway, D. W.; Arkani-Hamed, J.; Teskey, D. J.; Hood, P. J.

    1985-01-01

    Data from the MAGSAT mission were used to derive a global scalar magnetic anomaly map at an average altitude of about 400 km. It was possible to work with 2 data sets corresponding to dawn and dusk. The anomalies which were repeatable at dawn and at dusk was identified and the error limits of these anomalies were estimated. The repeatable anomalies were downward continued to about 10 km altitude. The anomalies over Canada were correlated quantitatively with bandpass filtered magnetic anomalies derived from aeromagnetic surveys. The close correlation indicates that the repeatable anomalies detected from orbit are due to geological causes. This correlation supports the geological significance of the global anomaly map.

  17. Brain Extraction and Fuzzy Tissue Segmentation in Cerebral 2D T1-Weigthed Magnetic Resonance Images

    OpenAIRE

    Bouchaib Cherradi; Omar Bouattane; Mohamed Youssfi; Abdelhadi Raihani

    2011-01-01

    In medical imaging, accurate segmentation of brain MR images is of interest for many brain manipulations. In this paper, we present a method for brain Extraction and tissues classification. An application of this method to the segmentation of simulated MRI cerebral images in three clusters will be made. The studied method is composed with different stages, first Brain Extraction from T1-weighted 2D MRI slices (TMBE) is performed as pre-processing procedure, then Histogram based centroids init...

  18. Using Proton Magnetic Resonance Imaging and Spectroscopy to Understand Brain "Activation"

    Science.gov (United States)

    Baslow, Morris H.; Guilfoyle, David N.

    2007-01-01

    Upon stimulation, areas of the brain associated with specific cognitive processing tasks may undergo observable physiological changes, and measures of such changes have been used to create brain maps for visualization of stimulated areas in task-related brain "activation" studies. These perturbations usually continue throughout the period of the…

  19. ST-Segment resolution and clinical outcome with ischemic postconditioning and comparison to magnetic resonance

    DEFF Research Database (Denmark)

    Lønborg, Jacob; Holmvang, Lene; Kelbæk, Henning;

    2010-01-01

    Ischemic postconditioning (IPost) during primary percutaneous coronary intervention (PPCI) is suggested to reduce myocardial damage. However, the association with ST-segment resolution (STR) and clinical outcome is not determined. The primary aim of this study was to evaluate the association of I...

  20. Diffusion Magnetic Resonance Imaging Patterns in Metabolic and Toxic Brain Disorders

    International Nuclear Information System (INIS)

    Purpose: To evaluate metabolic and toxic brain disorders that manifest with restricted, elevated, or both restricted and elevated diffusion patterns on diffusion magnetic resonance imaging (MRI). Material and Methods: Echo-planar diffusion MRI examinations were obtained in 34 pediatric patients with metabolic and toxic brain disorders proved by appropriate laboratory studies. The MRI unit operated at 1.5T with a gradient strength of 30 mT/meter, and a rise time of 600 s. b=1000 s/mm2 images and apparent diffusion coefficient (ADC) maps with ADC values were studied. Results: Three patterns were observed: 1. A restricted diffusion pattern (high signal on b=1000 s/mm2 images and low ADC values); 2. an elevated diffusion pattern (normal signal on b=1000 s/mm2 images and high ADC values); and 3. a mixed pattern (coexistent restricted and increased diffusion patterns in the same patient). Disorders manifesting with a restricted diffusion pattern included metachromatic leukodystrophy (n=2), phenylketonuria (n=3), maple syrup urine disease (intermediate form) (n=1), infantile neuroaxonal dystrophy (n=1), Leigh (n=2), Wilson (n=3), and Canavan disease (n=1). Disorders with an elevated diffusion pattern included phenylketonuria (n=1), adrenoleukodystrophy (n=1), merosin-deficient congenital muscular dystrophy (n=2), mucopolysaccharidosis (n=2), Lowe syndrome (n=1), Leigh (n=2), Alexander (n=1), Pelizaeus-Merzbacher (n=1), and Wilson (n=3) disease. Disorders with a mixed pattern included L-2 hydroxyglutaric aciduria (n=2), non-ketotic hyperglycinemia (n=1), infantile neuroaxonal dystrophy (n=2), maple syrup urine disease (n=1), and Leigh (n=1) disease. Conclusion: The findings suggested that the three different diffusion patterns reflect the histopathological changes associated with the disorders and different stages of a particular disorder. It is likely that the restricted diffusion pattern corresponds to abnormalities related to myelin, and the elevated diffusion pattern

  1. Correlation between voxel based morphometry and manual volumetry in magnetic resonance images of the human brain

    Directory of Open Access Journals (Sweden)

    Ricardo R. Uchida

    2008-03-01

    Full Text Available This is a comparative study between manual volumetry (MV and voxel based morphometry (VBM as methods of evaluating the volume of brain structures in magnetic resonance images. The volumes of the hippocampus and the amygdala of 16 panic disorder patients and 16 healthy controls measured through MV were correlated with the volumes of gray matter estimated by optimized modulated VBM. The chosen structures are composed almost exclusively of gray matter. Using a 4 mm Gaussian filter, statistically significant clusters were found bilaterally in the hippocampus and in the right amygdala in the statistical parametric map correlating with the respective manual volume. With the conventional 12 mm filter,a significant correlation was found only for the right hippocampus. Therefore,narrowfilters increase the sensitivity of the correlation procedure, especially when small brain structures are analyzed. The two techniques seem to consistently measure structural volume.Trata-se de estudo comparativo entre a volumetria manual(VM e a morfometria baseada no vóxel (MBV, como métodos de avaliação do volume de estruturas cerebrais. Os volumes do hipocampo e da amídala de 16 pacientes de pânico e 16 controles sadios medidos através da VM foram correlacionados com os volumes de matéria cinzenta estimados pela MBV.As estruturas escolhidas são constituídas quase exclusivamente de matéria cinzenta. Utilizando um filtro Gaussiano de 4 mm, encontram-se, bilateralmente, aglomerados significativos de correlação nas duas estruturas no mapa estatístico paramétrico, correspondendo ao respectivo volume manual. Com o filtro convencional de 12 mm, apenas uma correlação significativa foi encontrada no hipocampo direito. Portanto, filtros estreitos aumentam a sensibilidade do procedimento de correlação,especialmente quando estruturas pequenas são analisadas. Ambas as técnicas parecem medir consistentemente o volume estrutural.

  2. Diffusion Magnetic Resonance Imaging Patterns in Metabolic and Toxic Brain Disorders

    Energy Technology Data Exchange (ETDEWEB)

    Sener, R.N. [Ege Univ. Hospital, Bornova, Izmir (Turkey). Dept. of Radiology

    2004-08-01

    Purpose: To evaluate metabolic and toxic brain disorders that manifest with restricted, elevated, or both restricted and elevated diffusion patterns on diffusion magnetic resonance imaging (MRI). Material and Methods: Echo-planar diffusion MRI examinations were obtained in 34 pediatric patients with metabolic and toxic brain disorders proved by appropriate laboratory studies. The MRI unit operated at 1.5T with a gradient strength of 30 mT/meter, and a rise time of 600 s. b=1000 s/mm{sup 2} images and apparent diffusion coefficient (ADC) maps with ADC values were studied. Results: Three patterns were observed: 1. A restricted diffusion pattern (high signal on b=1000 s/mm{sup 2} images and low ADC values); 2. an elevated diffusion pattern (normal signal on b=1000 s/mm2 images and high ADC values); and 3. a mixed pattern (coexistent restricted and increased diffusion patterns in the same patient). Disorders manifesting with a restricted diffusion pattern included metachromatic leukodystrophy (n=2), phenylketonuria (n=3), maple syrup urine disease (intermediate form) (n=1), infantile neuroaxonal dystrophy (n=1), Leigh (n=2), Wilson (n=3), and Canavan disease (n=1). Disorders with an elevated diffusion pattern included phenylketonuria (n=1), adrenoleukodystrophy (n=1), merosin-deficient congenital muscular dystrophy (n=2), mucopolysaccharidosis (n=2), Lowe syndrome (n=1), Leigh (n=2), Alexander (n=1), Pelizaeus-Merzbacher (n=1), and Wilson (n=3) disease. Disorders with a mixed pattern included L-2 hydroxyglutaric aciduria (n=2), non-ketotic hyperglycinemia (n=1), infantile neuroaxonal dystrophy (n=2), maple syrup urine disease (n=1), and Leigh (n=1) disease. Conclusion: The findings suggested that the three different diffusion patterns reflect the histopathological changes associated with the disorders and different stages of a particular disorder. It is likely that the restricted diffusion pattern corresponds to abnormalities related to myelin, and the elevated

  3. Evaluation of 2D multiband EPI imaging for high-resolution, whole-brain, task-based fMRI studies at 3T: Sensitivity and slice leakage artifacts.

    Science.gov (United States)

    Todd, Nick; Moeller, Steen; Auerbach, Edward J; Yacoub, Essa; Flandin, Guillaume; Weiskopf, Nikolaus

    2016-01-01

    Functional magnetic resonance imaging (fMRI) studies that require high-resolution whole-brain coverage have long scan times that are primarily driven by the large number of thin slices acquired. Two-dimensional multiband echo-planar imaging (EPI) sequences accelerate the data acquisition along the slice direction and therefore represent an attractive approach to such studies by improving the temporal resolution without sacrificing spatial resolution. In this work, a 2D multiband EPI sequence was optimized for 1.5mm isotropic whole-brain acquisitions at 3T with 10 healthy volunteers imaged while performing simultaneous visual and motor tasks. The performance of the sequence was evaluated in terms of BOLD sensitivity and false-positive activation at multiband (MB) factors of 1, 2, 4, and 6, combined with in-plane GRAPPA acceleration of 2× (GRAPPA 2), and the two reconstruction approaches of Slice-GRAPPA and Split Slice-GRAPPA. Sensitivity results demonstrate significant gains in temporal signal-to-noise ratio (tSNR) and t-score statistics for MB 2, 4, and 6 compared to MB 1. The MB factor for optimal sensitivity varied depending on anatomical location and reconstruction method. When using Slice-GRAPPA reconstruction, evidence of false-positive activation due to signal leakage between simultaneously excited slices was seen in one instance, 35 instances, and 70 instances over the ten volunteers for the respective accelerations of MB 2×GRAPPA 2, MB 4×GRAPPA 2, and MB 6×GRAPPA 2. The use of Split Slice-GRAPPA reconstruction suppressed the prevalence of false positives significantly, to 1 instance, 5 instances, and 5 instances for the same respective acceleration factors. Imaging protocols using an acceleration factor of MB 2×GRAPPA 2 can be confidently used for high-resolution whole-brain imaging to improve BOLD sensitivity with very low probability for false-positive activation due to slice leakage. Imaging protocols using higher acceleration factors (MB 3 or MB 4

  4. Combining scanning tunneling microscopy and synchrotron radiation for high-resolution imaging and spectroscopy with chemical, electronic, and magnetic contrast

    International Nuclear Information System (INIS)

    The combination of high-brilliance synchrotron radiation with scanning tunneling microscopy opens the path to high-resolution imaging with chemical, electronic, and magnetic contrast. Here, the design and experimental results of an in-situ synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system are presented. The system is designed to allow monochromatic synchrotron radiation to enter the chamber, illuminating the sample with x-ray radiation, while an insulator-coated tip (metallic tip apex open for tunneling, electron collection) is scanned over the surface. A unique feature of the SXSTM is the STM mount assembly, designed with a two free-flex pivot, providing an angular degree of freedom for the alignment of the tip and sample with respect to the incoming x-ray beam. The system designed successfully demonstrates the ability to resolve atomic-scale corrugations. In addition, experiments with synchrotron x-ray radiation validate the SXSTM system as an accurate analysis technique for the study of local magnetic and chemical properties on sample surfaces. The SXSTM system's capabilities have the potential to broaden and deepen the general understanding of surface phenomena by adding elemental contrast to the high-resolution of STM. -- Highlights: ► Synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system designed. ► Unique STM mount design allows angular DOF for tip alignment with x-ray beam. ► System demonstrates ability to resolve atomic corrugations on HOPG. ► Studies show chemical sensitivity with STM tip from photocurrent and tunneling. ► Results show system's ability to study local magnetic (XMCD) properties on Fe films.

  5. Targeted brain derived neurotropic factors (BDNF delivery across the blood-brain barrier for neuro-protection using magnetic nano carriers: an in-vitro study.

    Directory of Open Access Journals (Sweden)

    Sudheesh Pilakka-Kanthikeel

    Full Text Available Parenteral use of drugs; such as opiates exert immunomodulatory effects and serve as a cofactor in the progression of HIV-1 infection, thereby potentiating HIV related neurotoxicity ultimately leading to progression of NeuroAIDS. Morphine exposure is known to induce apoptosis, down regulate cAMP response element-binding (CREB expression and decrease in dendritic branching and spine density in cultured cells. Use of neuroprotective agent; brain derived neurotropic factor (BDNF, which protects neurons against these effects, could be of therapeutic benefit in the treatment of opiate addiction. Previous studies have shown that BDNF was not transported through the blood brain barrier (BBB in-vivo.; and hence it is not effective in-vivo. Therefore development of a drug delivery system that can cross BBB may have significant therapeutic advantage. In the present study, we hypothesized that magnetically guided nanocarrier may provide a viable approach for targeting BDNF across the BBB. We developed a magnetic nanoparticle (MNP based carrier bound to BDNF and evaluated its efficacy and ability to transmigrate across the BBB using an in-vitro BBB model. The end point determinations of BDNF that crossed BBB were apoptosis, CREB expression and dendritic spine density measurement. We found that transmigrated BDNF was effective in suppressing the morphine induced apoptosis, inducing CREB expression and restoring the spine density. Our results suggest that the developed nanocarrier will provide a potential therapeutic approach to treat opiate addiction, protect neurotoxicity and synaptic density degeneration.

  6. Management of brain metastasis with magnetic resonance imaging and stereotactic irradiation attenuated benefits of prophylactic cranial irradiation in patients with limited-stage small cell lung cancer

    OpenAIRE

    Ozawa, Yuichi; Omae, Minako; Fujii, Masato; Matsui, Takashi; KATO, Masato; Sagisaka, Shinya; Asada, Kazuhiro; Karayama, Masato; Shirai, Toshihiro; Yasuda, Kazumasa; Nakamura, Yutaro; Inui, Naoki; Yamada, Kazunari; Yokomura, Koshi; Suda, Takafumi

    2015-01-01

    Background Magnetic resonance imaging (MRI) enables a more sensitive detection of brain metastasis and stereotactic irradiation (SRI) efficiently controls brain metastasis. In limited-stage small cell lung cancer (LS-SCLC), prophylactic cranial irradiation (PCI) in patients with good responses to initial treatment is recommended based on the survival benefit shown in previous clinical trials. However, none of these trials evaluated PCI effects using the management of brain metastasis with MRI...

  7. High-resolution magnetic resonance angiography of the internal carotid artery: 2D vs 3D TOF in stenotic disease

    Energy Technology Data Exchange (ETDEWEB)

    Carriero, A.; Magarelli, N.; Marano, R.; Ambrosini, R.; Bonomo, L. [Department of Radiology, University of Chieti (Italy); Scarabino, T. [IRCCS, S. Giovanni Rotondo, Foggia (Italy); Salvolini, U. [Department of Neuroradiology, University of Ancona (Italy)

    1998-10-01

    The aim of this study was to compare high-resolution 2D TOF with high-resolution 3D TOF in the study of internal carotid artery disease. Sixty-four patients with clinical signs of cerebrovascular insufficiency were studied with a superconductive 1.5 T magnet using two techniques: 2D and 3D TOF. Digital subtraction angiography (DSA) was the gold standard. The 2D TOF technique was performed using the following parameters: TR/TE/FA/MA 49 ms/9 ms/60 /512 x 256; the 3D TOF was performed with the following parameters: TR/TE/FA/MA 50 ms/8 ms/20 /512 x 256. The 2D TOF agreed with DSA in 116 of 128 diagnostic judgments (90 %) and overestimated seven times. The 3D TOF technique agreed with DSA in 125 of 128 diagnostic judgments (97 %) with one overestimation and two underestimations. There was no statistically significant difference (P < 0.05) between the two different techniques. Our study confirms the high reliability of themethodology carried out with the high-resolution 2D and 3D technique. (orig.) (orig.) With 1 fig., 5 refs.

  8. Possible promotion of neuronal differentiation in fetal rat brain neural progenitor cells after sustained exposure to static magnetism.

    Science.gov (United States)

    Nakamichi, Noritaka; Ishioka, Yukichi; Hirai, Takao; Ozawa, Shusuke; Tachibana, Masaki; Nakamura, Nobuhiro; Takarada, Takeshi; Yoneda, Yukio

    2009-08-15

    We have previously shown significant potentiation of Ca(2+) influx mediated by N-methyl-D-aspartate receptors, along with decreased microtubules-associated protein-2 (MAP2) expression, in hippocampal neurons cultured under static magnetism without cell death. In this study, we investigated the effects of static magnetism on the functionality of neural progenitor cells endowed to proliferate for self-replication and differentiate into neuronal, astroglial, and oligodendroglial lineages. Neural progenitor cells were isolated from embryonic rat neocortex and hippocampus, followed by culture under static magnetism at 100 mT and subsequent determination of the number of cells immunoreactive for a marker protein of particular progeny lineages. Static magnetism not only significantly decreased proliferation of neural progenitor cells without affecting cell viability, but also promoted differentiation into cells immunoreactive for MAP2 with a concomitant decrease in that for an astroglial marker, irrespective of the presence of differentiation inducers. In neural progenitors cultured under static magnetism, a significant increase was seen in mRNA expression of several activator-type proneural genes, such as Mash1, Math1, and Math3, together with decreased mRNA expression of the repressor type Hes5. These results suggest that sustained static magnetism could suppress proliferation for self-renewal and facilitate differentiation into neurons through promoted expression of activator-type proneural genes by progenitor cells in fetal rat brain.

  9. Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Tamar ePashut

    2014-06-01

    Full Text Available Although transcranial magnetic stimulation (TMS is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies.

  10. Proton magnetic resonance spectroscopy (1H MRS) of human brain tumours: assessment of differences between tumour types and its applicability in brain tumour categorization

    International Nuclear Information System (INIS)

    Our objective was to evaluate the usefulness of proton magnetic resonance spectroscopy (1H MRS) in categorizing brain tumours. In vivo single-voxel 1H MRS at an echo time of 136 ms was performed in 108 patients with brain neoplasms that included 29 meningiomas (MEN), 15 low-grade astrocytomas (LGA), 12 anaplastic astrocytomas (AA), 25 glioblastomas (GBM) and 27 metastases (MET). Time-domain fitted areas of nine resonances were evaluated in all spectra. Twenty-five additional tumours were prospectively included as independent test set. Differences in at least two resonances were found in all pairwise comparisons of tumour groups except in GBM vs MET. Large lipid resonance at 1.30 ppm was found to be characteristic of GBM and MET, and alanine was characteristic of MEN. Significant differences were found between LGA and AA in choline-containing compounds and total creatine resonances. When implemented in a stepwise algorithm, these findings correctly classified 84% (21 of 25) tumours in the independent test set. Some additional utility was found in glycine/myo-inositol at 3.55 ppm for bilateral differentiation between GBM and MET (9 of 11, 82% correct classification in the test set). 1H MRS provides useful information to categorize the most common brain tumours that can be implemented in clinical practice with satisfactory results. (orig.)

  11. Revisiting a historic human brain with magnetic resonance imaging - the first description of a divided central sulcus.

    Science.gov (United States)

    Schweizer, Renate; Helms, Gunther; Frahm, Jens

    2014-01-01

    In 1860 and 1862, the German physiologist Wagner published two studies, in which he compared the cortical surfaces of brain specimens. This provided the first account of a rare anatomical variation - bridges across the central sulci in both hemispheres connecting the forward and backward facing central convolutions in one of the brains. The serendipitous rediscovery of the preserved historic brain specimen in the collections at Göttingen University, being mistaken as the brain of the mathematician C.F. Gauss, allowed us to further investigate the morphology of the bridges Wagner had described with magnetic resonance imaging (MRI). On the historic lithograph, current photographs and MRI surface reconstructions of the brain, a connection across the central sulcus can only be seen in the left hemisphere. In the right hemisphere, contrary to the description of Wagner, a connecting structure is only present across the post-central sulcus. MRI reveals that the left-hemispheric bridge extends into the depth of the sulcus, forming a transverse connection between the two opposing gyri. This rare anatomical variation, generally not associated with neurological symptoms, would nowadays be categorized as a divided central sulcus. The left-hemispheric connection seen across the post-central sulcus, represents the very common case of a segmented post-central sulcus. MRI further disclosed a connection across the right-hemispheric central sulcus, which terminates just below the surface of the brain and is therefore not depicted on the historical lithography. This explains the apparent inconsistency between the bilateral description of bridges across the central sulci and the unilateral appearance on the brain surface. The results are discussed based on the detailed knowledge of anatomists of the late 19th century, who already recognized the divided central sulcus as an extreme variation of a deep convolution within the central sulcus.

  12. Revisiting a historic human brain with magnetic resonance imaging – the first description of a divided central sulcus

    Directory of Open Access Journals (Sweden)

    Renate eSchweizer

    2014-05-01

    Full Text Available In 1860 and 1862, the German physiologist Wagner published two studies, in which he compared the cortical surfaces of brain specimens. This provided the first account of a rare anatomical variation – bridges across the central sulci in both hemispheres connecting the forward and backward facing central convolutions in one of the brains. The serendipitous rediscovery of the preserved historic brain specimen in the collections at Göttingen University, being mistaken as the brain of the mathematician C.F. Gauss, allowed us to further investigate the morphology of the bridges Wagner had described with magnetic resonance imaging (MRI. On the historic lithograph, current photographs and MRI surface reconstructions of the brain, a connection across the central sulcus can only be seen in the left hemisphere. In the right hemisphere, contrary to the description of Wagner, a connecting structure is only present across the postcentral sulcus. MRI reveals that the left-hemispheric bridge extends into the depth of the sulcus, forming a transverse connection between the two opposing gyri. This rare anatomical variation, generally not associated with neurological symptoms, would nowadays be categorized as a divided central sulcus. The left-hemispheric connection seen across the postcentral sulcus, represents the very common case of a segmented postcentral sulcus. MRI further disclosed a connection across the right-hemispheric central sulcus, which terminates just below the surface of the brain and is therefore not depicted on the historical lithography. This explains the apparent inconsistency between the bilateral description of bridges across the central sulci and the unilateral appearance on the brain surface. The results are discussed based on the detailed knowledge of anatomists of the late 19th century, who already recognized the divided central sulcus as an extreme variation of a deep convolution within the central sulcus.

  13. High-resolution marine magnetic</