Scholars@Duke
Allen W Song

Allen W Song

Professor in Radiology
Radiology
allen.song@duke.edu
Brain Imaging and Analysis Ctr, Box 3918, Durham, NC 27710
40 Duke Medicine Circle, Davison 414, Box 3918, Durham, NC 27710

Selected Publications

Chronic cannabis use associated with subcortical topological reorganization of structural connectivity in adults.

Journal Article Drug Alcohol Depend · September 1, 2024 BACKGROUND: Cannabis is commonly used in the United States. However, chronic cannabis use has been linked to alterations in white matter (WM) integrity. Studies investigating WM in people who use cannabis (PWC) have produced varying results, which may be d ... Full text Link to item Cite

Flexible multi-purpose integrated RF/shim coil array for MRI and localized B0 shimming.

Journal Article Magn Reson Med · February 2024 PURPOSE: To develop a flexible, lightweight, and multi-purpose integrated parallel reception, excitation, and shimming (iPRES) coil array that can conform to the subject's anatomy and perform MR imaging and localized B0 shimming in different anatomical reg ... Full text Link to item Cite

Depth- and curvature-based quantitative susceptibility mapping analyses of cortical iron in Alzheimer's disease.

Journal Article Cereb Cortex · January 31, 2024 In addition to amyloid beta plaques and neurofibrillary tangles, Alzheimer's disease (AD) has been associated with elevated iron in deep gray matter nuclei using quantitative susceptibility mapping (QSM). However, only a few studies have examined cortical ... Full text Open Access Link to item Cite

Using latent profile analyses to classify subjects with anhedonia based on reward-related measures obtained in the FAST-MAS study.

Journal Article J Affect Disord · October 15, 2023 BACKGROUND: Growing evidence indicates that anhedonia is a multifaceted construct. This study examined the possibility of identifying subgroups of people with anhedonia using multiple reward-related measures to provide greater understanding the Research Do ... Full text Link to item Cite

High-resolution multi-shot diffusion imaging of structural networks in healthy neurocognitive aging.

Journal Article Neuroimage · July 15, 2023 Healthy neurocognitive aging has been associated with the microstructural degradation of white matter pathways that connect distributed gray matter regions, assessed by diffusion-weighted imaging (DWI). However, the relatively low spatial resolution of sta ... Full text Open Access Link to item Cite

Numerical simulations of an integrated radio-frequency/wireless coil design for simultaneous acquisition and wireless transfer of magnetic resonance imaging data.

Journal Article Phys Med Biol · June 8, 2023 Objective.A novel magnetic resonance imaging (MRI) radio-frequency (RF) coil design, termed an integrated RF/wireless (iRFW) coil design, can simultaneously perform MRI signal reception and far-field wireless data transfer with the same coil conductors bet ... Full text Link to item Cite

Column-based cortical depth analysis of the diffusion anisotropy and radiality in submillimeter whole-brain diffusion tensor imaging of the human cortical gray matter in vivo.

Journal Article Neuroimage · April 15, 2023 High-resolution diffusion tensor imaging (DTI) can noninvasively probe the microstructure of cortical gray matter in vivo. In this study, 0.9-mm isotropic whole-brain DTI data were acquired in healthy subjects with an efficient multi-band multi-shot echo-p ... Full text Link to item Cite

An iPRES-W Coil Array for Simultaneous Imaging and Wireless Localized B0 Shimming of the Cervical Spinal Cord.

Journal Article Magn Reson Med · August 2022 PURPOSE: To develop a wireless integrated parallel reception, excitation, and shimming (iPRES-W) coil array for simultaneous imaging and wireless localized B0 shimming, and to demonstrate its ability to correct for distortions in DTI of the spinal cord in ... Full text Link to item Cite

Strengthened and posterior-shifted structural rich-club organization in people who use cocaine.

Journal Article Drug Alcohol Depend · June 1, 2022 BACKGROUND: People with cocaine use disorder (CUD) often have abnormal cognitive function and brain structure. Cognition is supported by brain networks that typically have characteristics like rich-club organization, which is a group of regions that are hi ... Full text Link to item Cite

Recent Advances in Radio-Frequency Coil Technologies: Flexible, Wireless, and Integrated Coil Arrays.

Journal Article J Magn Reson Imaging · April 2022 Radio-frequency (RF) coils are to magnetic resonance imaging (MRI) scanners what eyes are to the human body. Because of their critical importance, there have been constant innovations driving the rapid development of RF coil technologies. Over the past fou ... Full text Link to item Cite

Cortical iron mediates age-related decline in fluid cognition.

Journal Article Hum Brain Mapp · February 15, 2022 Brain iron dyshomeostasis disrupts various critical cellular functions, and age-related iron accumulation may contribute to deficient neurotransmission and cell death. While recent studies have linked excessive brain iron to cognitive function in the conte ... Full text Open Access Link to item Cite

Changes in the geometry and robustness of diffusion tensor imaging networks: Secondary analysis from a randomized controlled trial of young autistic children receiving an umbilical cord blood infusion.

Journal Article Front Psychiatry · 2022 Diffusion tensor imaging (DTI) has been used as an outcome measure in clinical trials for several psychiatric disorders but has rarely been explored in autism clinical trials. This is despite a large body of research suggesting altered white matter structu ... Full text Link to item Cite

Application of an integrated radio-frequency/shim coil technology for signal recovery in fMRI.

Journal Article Magn Reson Med · December 2021 PURPOSE: Gradient-echo echo-planar imaging (EPI), which is typically used for blood oxygenation level-dependent (BOLD) functional MRI (fMRI), suffers from distortions and signal loss caused by localized B0 inhomogeneities. Such artifacts cannot be effectiv ... Full text Link to item Cite

DTI Tract-Based Quantitative Susceptibility Mapping: An Initial Feasibility Study to Investigate the Potential Role of Myelination in Brain Connectivity Change in Cerebral Palsy Patients During Autologous Cord Blood Cell Therapy Using a Rotationally-Invariant Quantitative Measure.

Journal Article J Magn Reson Imaging · January 2021 BACKGROUND: Previous studies using diffusion tensor imaging (DTI)-based connectome analysis revealed improved connectivity in cerebral palsy (CP) patients who underwent autologous umbilical cord blood (UCB) stem-cell therapy. However, the potential mechani ... Full text Link to item Cite

Measuring robustness of brain networks in autism spectrum disorder with Ricci curvature.

Journal Article Sci Rep · July 2, 2020 Ollivier-Ricci curvature is a method for measuring the robustness of connections in a network. In this work, we use curvature to measure changes in robustness of brain networks in children with autism spectrum disorder (ASD). In an open label clinical tria ... Full text Open Access Link to item Cite

A Phase II Randomized Clinical Trial of the Safety and Efficacy of Intravenous Umbilical Cord Blood Infusion for Treatment of Children with Autism Spectrum Disorder.

Journal Article J Pediatr · July 2020 OBJECTIVE: To evaluate whether umbilical cord blood (CB) infusion is safe and associated with improved social and communication abilities in children with autism spectrum disorder (ASD). STUDY DESIGN: This prospective, randomized, placebo-controlled, doubl ... Full text Open Access Link to item Cite

Magnetic resonance imaging volumetric analysis in patients with Alternating hemiplegia of childhood: A pilot study.

Journal Article Eur J Paediatr Neurol · May 2020 Quantitative MRI is increasingly being used as a biomarker in neurological disorders. Cerebellar atrophy occurs in some Alternating Hemiplegia of Childhood (AHC) patients. However, it is not known if cerebellar atrophy can be a potential biomarker in AHC o ... Full text Link to item Cite

A randomized proof-of-mechanism trial applying the 'fast-fail' approach to evaluating κ-opioid antagonism as a treatment for anhedonia.

Journal Article Nat Med · May 2020 The National Institute of Mental Health (NIMH) 'fast-fail' approach seeks to improve too-often-misleading early-phase drug development methods by incorporating biomarker-based proof-of-mechanism (POM) testing in phase 2a. This first comprehensive applicati ... Full text Link to item Cite

Toward direct MRI of neuro-electro-magnetic oscillations in the human brain.

Journal Article Magn Reson Med · June 2019 PURPOSE: Neuroimaging techniques are widely used to investigate the function of the human brain, but none are currently able to accurately localize neuronal activity with both high spatial and temporal specificity. Here, a new in vivo MRI acquisition and a ... Full text Link to item Cite

Integrated radio-frequency/wireless coil design for simultaneous MR image acquisition and wireless communication.

Journal Article Magn Reson Med · March 2019 PURPOSE: An innovative radio-frequency (RF) coil design that allows RF currents both at the Larmor frequency and in a wireless communication band to flow on the same coil is proposed to enable simultaneous MRI signal reception and wireless data transfer, t ... Full text Link to item Cite

White Matter Tract Changes Associated with Clinical Improvement in an Open-Label Trial Assessing Autologous Umbilical Cord Blood for Treatment of Young Children with Autism.

Journal Article Stem Cells Transl Med · February 2019 Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by social communication deficits and the presence of restricted interests and repetitive behaviors. We have previously reported significant improvements in behavior ... Full text Open Access Link to item Cite

Simultaneous and inherent correction of B0 and eddy-current induced distortions in high-resolution diffusion MRI using reversed polarity gradients and multiplexed sensitivity encoding (RPG-MUSE).

Journal Article Neuroimage · December 2018 In diffusion MRI (dMRI), static magnetic field (B0) inhomogeneity and time varying gradient eddy currents induce spatial distortions in reconstructed images. These distortions are exacerbated when high spatial resolutions are used, and many field-mapping b ... Full text Link to item Cite

Structural connectome differences in HIV infection: brain network segregation associated with nadir CD4 cell count.

Journal Article J Neurovirol · August 2018 This study investigated structural brain organization using diffusion tensor imaging (DTI) in 35 HIV-positive and 35 HIV-negative individuals. We used global and nodal graph theory metrics to investigate whether HIV was associated with differences in brain ... Full text Link to item Cite

Adaptive integrated parallel reception, excitation, and shimming (iPRES-A) with microelectromechanical systems switches.

Journal Article Magn Reson Med · July 2018 PURPOSE: Integrated parallel reception, excitation, and shimming coil arrays with N shim loops per radio-frequency (RF) coil element (iPRES(N)) allow an RF current and N direct currents (DC) to flow in each coil element, enabling simultaneous reception/exc ... Full text Link to item Cite

Training with brain-machine interfaces, visuo-tactile feedback and assisted locomotion improves sensorimotor, visceral, and psychological signs in chronic paraplegic patients.

Journal Article PLoS One · 2018 Spinal cord injury (SCI) induces severe deficiencies in sensory-motor and autonomic functions and has a significant negative impact on patients' quality of life. There is currently no systematic rehabilitation technique assuring recovery of the neurologica ... Full text Link to item Cite

Effect of Autologous Cord Blood Infusion on Motor Function and Brain Connectivity in Young Children with Cerebral Palsy: A Randomized, Placebo-Controlled Trial.

Journal Article Stem Cells Transl Med · December 2017 Cerebral palsy (CP) is a condition affecting young children that causes lifelong disabilities. Umbilical cord blood cells improve motor function in experimental systems via paracrine signaling. After demonstrating safety, we conducted a phase II trial of a ... Full text Open Access Link to item Cite

3D-MB-MUSE: A robust 3D multi-slab, multi-band and multi-shot reconstruction approach for ultrahigh resolution diffusion MRI.

Journal Article Neuroimage · October 1, 2017 Recent advances in achieving ultrahigh spatial resolution (e.g. sub-millimeter) diffusion MRI (dMRI) data have proven highly beneficial in characterizing tissue microstructures in organs such as the brain. However, the routine acquisition of in-vivo dMRI d ... Full text Link to item Cite

Cortical and Subcortical Coordination of Visual Spatial Attention Revealed by Simultaneous EEG-fMRI Recording.

Journal Article J Neurosci · August 16, 2017 Visual spatial attention has been studied in humans with both electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) individually. However, due to the intrinsic limitations of each of these methods used alone, our understanding of th ... Full text Link to item Cite

Phase-updated regularized SENSE for navigator-free multishot diffusion imaging.

Journal Article Magn Reson Med · July 2017 PURPOSE: Either SENSE+CG or POCS-ICE methods can be used to correct for motion-induced phase errors in navigator-free multishot diffusion imaging. SENSE+CG has the advantage of a fast convergence, however, occasionally the convergence can be unstable, thus ... Full text Link to item Cite

Plasma cytokines associated with febrile status epilepticus in children: A potential biomarker for acute hippocampal injury.

Journal Article Epilepsia · June 2017 OBJECTIVE: Our aim was to explore the association between plasma cytokines and febrile status epilepticus (FSE) in children, as well as their potential as biomarkers of acute hippocampal injury. METHODS: Analysis was performed on residual samples of childr ... Full text Link to item Cite

Integrated parallel reception, excitation, and shimming (iPRES) with multiple shim loops per radio-frequency coil element for improved B0 shimming.

Journal Article Magn Reson Med · May 2017 PURPOSE: Integrated parallel reception, excitation, and shimming (iPRES) coil arrays allow radio-frequency currents and direct currents to flow in the same coils, which enables excitation/reception and localized B0 shimming with a single coil array. The pu ... Full text Link to item Cite

Maintenance and Representation of Mind Wandering during Resting-State fMRI.

Journal Article Sci Rep · January 12, 2017 Major advances in resting-state functional magnetic resonance imaging (fMRI) techniques in the last two decades have provided a tool to better understand the functional organization of the brain both in health and illness. Despite such developments, charac ... Full text Open Access Link to item Cite

Frontal Hypoactivation During a Working Memory Task in Children With 22q11 Deletion Syndrome.

Journal Article J Child Neurol · January 2017 Impairments in executive function, such as working memory, are almost universal in children with chromosome 22q11.2 deletion syndrome. Delineating the neural underpinnings of these functions would enhance understanding of these impairments. In this study, ... Full text Link to item Cite

Risk factors for subsequent febrile seizures in the FEBSTAT study.

Journal Article Epilepsia · July 2016 OBJECTIVES: To identify risk and risk factors for developing a subsequent febrile seizure (FS) in children with a first febrile status epilepticus (FSE) compared to a first simple febrile seizure (SFS). To identify home use of rescue medications for subseq ... Full text Link to item Cite

Multi-site study of diffusion metric variability: effects of site, vendor, field strength, and echo time on regions-of-interest and histogram-bin analyses.

Conference Proc SPIE Int Soc Opt Eng · February 27, 2016 It is now common for magnetic-resonance-imaging (MRI) based multi-site trials to include diffusion-weighted imaging (DWI) as part of the protocol. It is also common for these sites to possess MR scanners of different manufacturers, different software and h ... Full text Link to item Cite

Multi-site Study of Diffusion Metric Variability: Characterizing the Effects of Site, Vendor, Field Strength, and Echo Time using the Histogram Distance.

Conference Proc SPIE Int Soc Opt Eng · February 27, 2016 MRI-based multi-site trials now routinely include some form of diffusion-weighted imaging (DWI) in their protocol. These studies can include data originating from scanners built by different vendors, each with their own set of unique protocol restrictions, ... Full text Link to item Cite

Motion immune diffusion imaging using augmented MUSE for high-resolution multi-shot EPI.

Journal Article Magn Reson Med · February 2016 PURPOSE: To develop new techniques for reducing the effects of microscopic and macroscopic patient motion in diffusion imaging acquired with high-resolution multishot echo-planar imaging. THEORY: The previously reported multiplexed sensitivity encoding (MU ... Full text Link to item Cite

Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

Journal Article Neuroimage · September 2015 The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in ... Full text Link to item Cite

Effects of repetitive transcranial magnetic stimulation on motor symptoms in Parkinson disease: a systematic review and meta-analysis.

Journal Article JAMA Neurol · April 2015 IMPORTANCE: Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive neuromodulation technique that has been closely examined as a possible treatment for Parkinson disease (PD). However, results evaluating the effectiveness of rTMS in PD are mi ... Full text Link to item Cite

Association between increased magnetic susceptibility of deep gray matter nuclei and decreased motor function in healthy adults.

Journal Article Neuroimage · January 15, 2015 In the human brain, iron is more prevalent in gray matter than in white matter, and deep gray matter structures, particularly the globus pallidus, putamen, caudate nucleus, substantia nigra, red nucleus, and dentate nucleus, exhibit especially high iron co ... Full text Open Access Link to item Cite

Brain structural connectivity increases concurrent with functional improvement: evidence from diffusion tensor MRI in children with cerebral palsy during therapy.

Journal Article Neuroimage Clin · 2015 Cerebral Palsy (CP) refers to a heterogeneous group of permanent but non-progressive movement disorders caused by injury to the developing fetal or infant brain (Bax et al., 2005). Because of its serious long-term consequences, effective interventions that ... Full text Open Access Link to item Cite

Preschool anxiety disorders predict different patterns of amygdala-prefrontal connectivity at school-age.

Journal Article PLoS One · 2015 OBJECTIVE: In this prospective, longitudinal study of young children, we examined whether a history of preschool generalized anxiety, separation anxiety, and/or social phobia is associated with amygdala-prefrontal dysregulation at school-age. As an explora ... Full text Open Access Link to item Cite

Correction for Eddy Current-Induced Echo-Shifting Effect in Partial-Fourier Diffusion Tensor Imaging.

Journal Article Biomed Res Int · 2015 In most diffusion tensor imaging (DTI) studies, images are acquired with either a partial-Fourier or a parallel partial-Fourier echo-planar imaging (EPI) sequence, in order to shorten the echo time and increase the signal-to-noise ratio (SNR). However, edd ... Full text Open Access Link to item Cite

Integrated RF/shim coil array for parallel reception and localized B0 shimming in the human brain.

Journal Article Neuroimage · December 2014 The purpose of this work was to develop a novel integrated radiofrequency and shim (RF/shim) coil array that can perform parallel reception and localized B0 shimming in the human brain with the same coils, thereby maximizing both the signal-to-noise ratio ... Full text Link to item Cite

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

Journal Article Brain Connect · November 2014 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 ... Full text Open Access Link to item Cite

Differential developmental trajectories of magnetic susceptibility in human brain gray and white matter over the lifespan.

Journal Article Hum Brain Mapp · June 2014 As indicated by several recent studies, magnetic susceptibility of the brain is influenced mainly by myelin in the white matter and by iron deposits in the deep nuclei. Myelination and iron deposition in the brain evolve both spatially and temporally. This ... Full text Open Access Link to item Cite

Regionally selective atrophy of subcortical structures in prodromal HD as revealed by statistical shape analysis.

Journal Article Hum Brain Mapp · March 2014 Huntington disease (HD) is a neurodegenerative disorder that involves preferential atrophy in the striatal complex and related subcortical nuclei. In this article, which is based on a dataset extracted from the PREDICT-HD study, we use statistical shape an ... Full text Link to item Cite

Dynamic and inherent B0 correction for DTI using stimulated echo spiral imaging.

Journal Article Magn Reson Med · March 2014 PURPOSE: To present a novel technique for high-resolution stimulated echo diffusion tensor imaging with self-navigated interleaved spirals readout trajectories that can inherently and dynamically correct for image artifacts due to spatial and temporal vari ... Full text Link to item Cite

Cortical depth dependence of the diffusion anisotropy in the human cortical gray matter in vivo.

Journal Article PLoS One · 2014 Diffusion tensor imaging (DTI) is typically used to study white matter fiber pathways, but may also be valuable to assess the microstructure of cortical gray matter. Although cortical diffusion anisotropy has previously been observed in vivo, its cortical ... Full text Link to item Cite

Integrated parallel reception, excitation, and shimming (iPRES).

Journal Article Magn Reson Med · July 2013 PURPOSE: To develop a new concept for a hardware platform that enables integrated parallel reception, excitation, and shimming. THEORY: This concept uses a single coil array rather than separate arrays for parallel excitation/reception and B0 shimming. It ... Full text Link to item Cite

A robust multi-shot scan strategy for high-resolution diffusion weighted MRI enabled by multiplexed sensitivity-encoding (MUSE).

Journal Article Neuroimage · May 15, 2013 Diffusion weighted magnetic resonance imaging (DWI) data have been mostly acquired with single-shot echo-planar imaging (EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in single-shot EPI, even when the par ... Full text Link to item Cite

Diffuse reduction of white matter connectivity in cerebral palsy with specific vulnerability of long range fiber tracts.

Journal Article Neuroimage Clin · 2013 Cerebral palsy (CP) is a heterogeneous group of non-progressive motor disorders caused by injury to the developing fetal or infant brain. Although the defining feature of CP is motor impairment, numerous other neurodevelopmental disabilities are associated ... Full text Open Access Link to item Cite

Inherent correction of motion-induced phase errors in multishot spiral diffusion-weighted imaging.

Journal Article Magn Reson Med · October 2012 Multishot spiral imaging is a promising alternative to echo-planar imaging for high-resolution diffusion-weighted imaging and diffusion tensor imaging. However, subject motion in the presence of diffusion-weighting gradients causes phase inconsistencies am ... Full text Link to item Cite

Functional neuroimaging of treatment effects in psychiatry: methodological challenges and recommendations.

Journal Article Int J Neurosci · September 2012 Functional magnetic resonance imaging (fMRI) has helped to elucidate the neurobiological bases of psychiatric and neurodevelopmental disorders by localizing etiologically-relevant aberrations in brain function. Functional MRI also has shown great promise t ... Full text Link to item Cite

Diffusion modulation of the fMRI signal: early investigations on the origin of the BOLD signal.

Journal Article Neuroimage · August 15, 2012 The early 1990s was a very special period for functional MRI (fMRI). Many original concepts were formed during that period which helped set up the foundations for modern neuroimaging development. I was fortunate to be in graduate school at the time. I was ... Full text Link to item Cite

Acceleration of high angular and spatial resolution diffusion imaging using compressed sensing

Journal Article Proceedings - International Symposium on Biomedical Imaging · August 15, 2012 Achieving simultaneously high angular and spatial resolution in diffusion imaging is challenging because of the long acquisition times involved. We propose a novel compressed sensing method to acquire high angular and spatial resolution diffusion imaging d ... Full text Cite

The involvement of the dopaminergic midbrain and cortico-striatal-thalamic circuits in the integration of reward prospect and attentional task demands.

Journal Article Cereb Cortex · March 2012 Reward has been shown to promote human performance in multiple task domains. However, an important debate has developed about the uniqueness of reward-related neural signatures associated with such facilitation, as similar neural patterns can be triggered ... Full text Link to item Cite

Diffusion tensor imaging of cerebral white matter integrity in cognitive aging.

Journal Article Biochim Biophys Acta · March 2012 In this article we review recent research on diffusion tensor imaging (DTI) of white matter (WM) integrity and the implications for age-related differences in cognition. Neurobiological mechanisms defined from DTI analyses suggest that a primary dimension ... Full text Open Access Link to item Cite

Two-dimensional phase cycled reconstruction for inherent correction of echo-planar imaging Nyquist artifacts.

Journal Article Magn Reson Med · October 2011 The inconsistency of k-space trajectories results in Nyquist artifacts in echo-planar imaging (EPI). Traditional techniques often only correct for phase errors along the frequency-encoding direction (one-dimensional correction), which may leave significant ... Full text Link to item Cite

Dynamic correction of artifacts due to susceptibility effects and time-varying eddy currents in diffusion tensor imaging.

Journal Article Neuroimage · August 15, 2011 In diffusion tensor imaging (DTI), spatial and temporal variations of the static magnetic field (B(0)) caused by susceptibility effects and time-varying eddy currents result in severe distortions, blurring, and misregistration artifacts, which in turn lead ... Full text Link to item Cite

Structural connectivity of the frontal lobe in children with drug-resistant partial epilepsy.

Journal Article Epilepsy Behav · May 2011 The superior longitudinal fasciculus (SLF) II and cingulum are two white matter tracts important for attention and other frontal lobe functions. These functions are often disturbed in children with drug-resistant (DR) partial epilepsy, even when no abnorma ... Full text Link to item Cite

Myelin water weighted diffusion tensor imaging.

Journal Article Neuroimage · October 15, 2010 In this study we describe our development and implementation of a magnetization transfer (MT) prepared stimulated-echo diffusion tensor imaging (DTI) technique that can be made sensitive to the microanatomy of myelin tissue. The short echo time (TE) enable ... Full text Link to item Cite

Application of k-space energy spectrum analysis for inherent and dynamic B0 mapping and deblurring in spiral imaging.

Journal Article Magn Reson Med · October 2010 Spiral imaging is vulnerable to spatial and temporal variations of the amplitude of the static magnetic field (B(0)) caused by susceptibility effects, eddy currents, chemical shifts, subject motion, physiological noise, and system instabilities, resulting ... Full text Link to item Cite

White matter abnormalities in bipolar disorder: insights from diffusion tensor imaging studies.

Journal Article J Neural Transm (Vienna) · May 2010 Diffusion tensor imaging (DTI) is a neuroimaging technique with the potential to elucidate white matter abnormalities. Recently, it has been applied to help in better understanding of the pathophysiology of bipolar disorder (BD). This review sought to synt ... Full text Link to item Cite

Apparent diffusion coefficient dependent fMRI: Spatiotemporal characteristics and implications on calibrated fMRI

Journal Article International Journal of Imaging Systems and Technology · March 1, 2010 In this manuscript, we review the development of an alternative functional magnetic resonance imaging (fMRI) contrast mechanism based on the apparent diffusion coefficient (ADC), in light of the recent progress in other complementary functional imaging con ... Full text Cite

Distinct value signals in anterior and posterior ventromedial prefrontal cortex.

Journal Article J Neurosci · February 17, 2010 The core feature of an economic exchange is a decision to trade one good for another, based on a comparison of relative value. Economists have long recognized, however, that the value an individual ascribes to a good during decision making (i.e., their rel ... Full text Link to item Cite

The Saccadic Re-Centering Bias is Associated with Activity Changes in the Human Superior Colliculus.

Journal Article Front Hum Neurosci · 2010 Being able to effectively explore our visual world is of fundamental importance, and it has been suggested that the straight-ahead gaze (primary position) might play a special role in this context. We employed fMRI in humans to investigate how neural activ ... Full text Link to item Cite

Cerebral white matter integrity and cognitive aging: contributions from diffusion tensor imaging.

Journal Article Neuropsychol Rev · December 2009 The integrity of cerebral white matter is critical for efficient cognitive functioning, but little is known regarding the role of white matter integrity in age-related differences in cognition. Diffusion tensor imaging (DTI) measures the directional displa ... Full text Link to item Cite

Measurement of spontaneous signal fluctuations in fMRI: adult age differences in intrinsic functional connectivity.

Journal Article Brain Struct Funct · October 2009 Functional connectivity (FC) reflects the coherence of spontaneous, low-frequency fluctuations in functional magnetic resonance imaging (fMRI) data. We report a behavior-based connectivity analysis method, in which whole-brain data are used to identify beh ... Full text Link to item Cite

Cortical depth dependence and implications on the neuronal specificity of the functional apparent diffusion coefficient contrast.

Journal Article Neuroimage · August 1, 2009 Although the blood oxygenation level-dependent (BOLD) contrast is widely used in functional MRI (fMRI), its spatial specificity is compromised by the diversity of the participating vasculature, including large draining veins. Previous studies have shown th ... Full text Link to item Cite

Biochemical abnormalities of the medial temporal lobe and medial prefrontal cortex in late-life depression.

Journal Article Psychiatry Res · April 30, 2009 We utilized single-voxel (1)H magnetic resonance spectroscopy (MRS) to investigate biochemical abnormalities related to late-life depression in the medial prefrontal cortex and medial temporal lobe. Fourteen elderly subjects whose depression responded to t ... Full text Link to item Cite

Investigations on spinal cord fMRI of cats under ketamine.

Journal Article Neuroimage · January 15, 2009 Functional magnetic resonance imaging (fMRI) of the spinal cord has been the subject of intense research for the last ten years. An important motivation for this technique is its ability to detect non-invasively neuronal activity in the spinal cord related ... Full text Link to item Cite

Dynamic MRI of small electrical activity.

Journal Article Methods Mol Biol · 2009 Neuroscience methods entailing in vivo measurements of brain activity have greatly contributed to our understanding of brain function for the past decades, from the invasive early studies in animals using single-cell electrical recordings, to the noninvasi ... Full text Link to item Cite

Differentiating sensitivity of post-stimulus undershoot under diffusion weighting: implication of vascular and neuronal hierarchy.

Journal Article PLoS One · August 13, 2008 The widely used blood oxygenation level dependent (BOLD) signal during brain activation, as measured in typical fMRI methods, is composed of several distinct phases, the last of which, and perhaps the least understood, is the post-stimulus undershoot. Alth ... Full text Open Access Link to item Cite

Integrated SENSE DTI with correction of susceptibility- and eddy current-induced geometric distortions.

Journal Article Neuroimage · March 1, 2008 Diffusion tensor imaging (DTI) is vulnerable to geometric distortions caused by subject-dependent susceptibility effects and diffusion-weighting direction-dependent eddy currents. Although the introduction of sensitivity encoding (SENSE) has reduced the ov ... Full text Link to item Cite

Lorentz effect imaging of ionic currents in solution.

Journal Article J Magn Reson · March 2008 Current functional MRI techniques relying on hemodynamic modulations are inherently limited in their ability to accurately localize neural activity in space and time. To address these limitations, we previously proposed a novel technique based on the Loren ... Full text Link to item Cite

Single-shot dual-z-shimmed sensitivity-encoded spiral-in/out imaging for functional MRI with reduced susceptibility artifacts.

Journal Article Magn Reson Med · January 2008 Blood oxygenation level-dependent (BOLD) functional MRI (fMRI) can be severely hampered by signal loss due to susceptibility-induced static magnetic field (B(0)) inhomogeneities near air/tissue interfaces. A single-shot spiral-in/out sequence with a z-shim ... Full text Link to item Cite

Diffusion tensor imaging fiber tracking with local tissue property sensitivity: phantom and in vivo validation.

Journal Article Magn Reson Imaging · January 2008 Diffusion tensor imaging (DTI) provides directional information that can be used to delineate brain white matter connections noninvasively via fiber tracking. The most commonly used methods for tractography are based on the streamline tracking algorithm fo ... Full text Link to item Cite

Component structure of event-related fMRI responses in the different neurovascular compartments.

Journal Article Magn Reson Imaging · April 2007 In most functional magnetic resonance imaging (fMRI) studies, brain activity is localized by observing changes in the blood oxygenation level-dependent (BOLD) signal that are believed to arise from capillaries, venules and veins in and around the active ne ... Full text Link to item Cite

Single-shot ADC imaging for fMRI.

Journal Article Magn Reson Med · February 2007 It has been suggested that apparent diffusion coefficient (ADC) contrast can be sensitive to cerebral blood flow (CBF) changes during brain activation. However, current ADC imaging techniques have an inherently low temporal resolution due to the requiremen ... Full text Link to item Cite

Endogenous functional CBV contrast revealed by diffusion weighting.

Journal Article NMR Biomed · December 2006 Functional MRI (fMRI) based on the blood oxygenation level dependent (BOLD) contrast often suffers from a lack of specificity because of the vascular spread of oxygenation changes. It is suggested from the optical imaging and animal fMRI literature that ce ... Full text Link to item Cite

Finding neuroelectric activity under magnetic-field oscillations (NAMO) with magnetic resonance imaging in vivo.

Journal Article Proc Natl Acad Sci U S A · August 15, 2006 Neuroimaging techniques are among the most important tools for investigating the function of the human nervous system and for improving the clinical diagnosis of neurological disorders. However, most commonly used techniques are limited by their invasivene ... Full text Link to item Cite

Dependence of gradient-echo and spin-echo BOLD fMRI at 4 T on diffusion weighting.

Journal Article NMR Biomed · August 2006 Diffusion weighting and spin-echo (SE) acquisitions can be used to help improve the spatial localization of BOLD fMRI at the cost of reduced acquisition rates and lower signal-to-noise ratio (SNR). To evaluate these costs, SE and gradient-echo (GE) data we ... Full text Link to item Cite

Single-voxel 1H PRESS at 4.0 T: precision and variability of measurements in anterior cingulate and hippocampus.

Journal Article NMR Biomed · June 2006 The precision [coefficient of variation or CV (%) = 100SD/X] of single-voxel point resolved spectroscopic data was characterized bilaterally, in anterior cingulate and in hippocampus, at 4.0 T in a healthy subject. Data acquisition was replicated 10 times ... Full text Link to item Cite

Synchronized detection of minute electrical currents with MRI using Lorentz effect imaging.

Journal Article J Magn Reson · March 2006 The blood oxygenation level-dependent (BOLD) effect is the most commonly used contrast mechanism in functional magnetic resonance imaging (fMRI), due to its relatively high spatial resolution and sensitivity. However, the ability of BOLD fMRI to accurately ... Full text Link to item Cite

Correction for direction-dependent distortions in diffusion tensor imaging using matched magnetic field maps.

Journal Article Neuroimage · March 2006 Diffusion tensor imaging (DTI) has seen increased usage in clinical and basic science research in the past decade. By assessing the water diffusion anisotropy within biological tissues, e.g. brain, researchers can infer different fiber structures important ... Full text Link to item Cite

Nonuniform activity of human calf muscles during an exercise task.

Journal Article Arch Phys Med Rehabil · October 2005 OBJECTIVES: To determine the distribution of leg muscle activity during heel raises using magnetic resonance imaging (MRI) with special emphasis on quantifying activity across multiple axial sections and to determine if there are differences among portions ... Full text Link to item Cite

Decisions under uncertainty: probabilistic context influences activation of prefrontal and parietal cortices.

Journal Article J Neurosci · March 30, 2005 Many decisions are made under uncertainty; that is, with limited information about their potential consequences. Previous neuroimaging studies of decision making have implicated regions of the medial frontal lobe in processes related to the resolution of u ... Full text Link to item Cite

Amygdala activation to sad pictures during high-field (4 tesla) functional magnetic resonance imaging.

Journal Article Emotion · March 2005 Fear-related processing in the amygdala has been well documented, but its role in signaling other emotions remains controversial. The authors recovered signal loss in the amygdala at high-field strength using an inward spiral pulse sequence and probed its ... Full text Link to item Cite

B factor dependence of the temporal characteristics of brain activation using dynamic apparent diffusion coefficient contrast.

Journal Article Magn Reson Med · December 2004 Functional MRI studies to date have been generally performed using the blood oxygenation level dependent (BOLD) contrast mechanism. Recently, it has been proposed that dynamic change in the apparent diffusion coefficient (ADC), measured using intravoxel in ... Full text Link to item Cite

Changes in magnetization transfer MRI correlate with spreading depression-induced astroglial reactivity and increased protein expression in mice.

Journal Article AJR Am J Roentgenol · December 2004 OBJECTIVE: Gliosis refers to a range of glial cell transformations that vary according to specific brain pathologic states. Disease, however, is not a prerequisite for gliosis because glial reactivity may also be seen in regions of increased physiologic ac ... Full text Link to item Cite

The BOLD fMRI refractory effect is specific to stimulus attributes: evidence from a visual motion paradigm.

Journal Article Neuroimage · September 2004 Functional magnetic resonance imaging (fMRI) studies have demonstrated that the blood oxygenation level-dependent (BOLD) hemodynamic response (HDR) to a stimulus is reduced by the previous presentation of a similar stimulus. We investigated the dependence ... Full text Link to item Cite

The spatial and temporal characteristics of the apparent-diffusion-coefficient-dependent fMRI signal changes during visual stimulation.

Journal Article J Neural Eng · March 2004 The blood oxygenation level dependent (BOLD) contrast has been commonly used to detect fMRI signal. The majority of the BOLD signals are believed to arise from the venous and capillary networks. However, only those from the capillaries are spatially close ... Full text Link to item Cite

Hemodynamic correlates of stimulus repetition in the visual and auditory cortices: an fMRI study.

Journal Article Neuroimage · March 2004 We examined the effects of stimulus repetition upon the evoked hemodynamic response (HDR) in auditory and visual cortices measured by magnetic resonance imaging in two experiments. Experiment 1 focused on the effects of the interval duration between two id ... Full text Link to item Cite

Linking hemodynamic and electrophysiological measures of brain activity: evidence from functional MRI and intracranial field potentials.

Journal Article Cereb Cortex · February 2004 We investigated the relation between electrophysiological and hemodynamic measures of brain activity through comparison of intracranially recorded event-related local field potentials (ERPs) and blood-oxygenation level dependent functional magnetic resonan ... Full text Link to item Cite

Functional parcellation of attentional control regions of the brain.

Journal Article J Cogn Neurosci · 2004 Recently, a number of investigators have examined the neural loci of psychological processes enabling the control of visual spatial attention using cued-attention paradigms in combination with event-related functional magnetic resonance imaging. Findings f ... Full text Open Access Link to item Cite

FMRI signal source analysis using diffusion-weighted spiral-in acquisition.

Journal Article Conf Proc IEEE Eng Med Biol Soc · 2004 Despite the tremendous growth in functional magnetic resonance imaging (fMRI), susceptibility induced static field inhomogeneity at air/tissue interface have limited the study of ventral brain regions engaged in object recognition and other processes. Furt ... Full text Link to item Cite

Fast functional brain signal changes detected by diffusion weighted fMRI.

Journal Article Magn Reson Imaging · October 2003 Functional magnetic resonance imaging (fMRI) has become the method of choice in the study of system neuroscience, as evidenced by an explosion of such literature in the past decade. Contrast mechanisms based on the blood oxygenation level, volume, and flow ... Full text Link to item Cite

Word frequency and subsequent memory effects studied using event-related fMRI.

Journal Article Neuroimage · October 2003 Event-related fMRI was used to evaluate the effect of printed word frequency on the subsequent recognition of words incidentally encoded while 16 healthy right-handed volunteers performed living/nonliving judgments. Semantic judgment took longer for low-fr ... Full text Link to item Cite

Functional activation using apparent diffusion coefficient-dependent contrast allows better spatial localization to the neuronal activity: evidence using diffusion tensor imaging and fiber tracking.

Journal Article Neuroimage · October 2003 Recent studies suggested that functional activation using apparent diffusion coefficient (ADC) contrast can be used to detect synchronized functional MRI (fMRI) signal changes during brain activation. Such changes may reflect better spatial localization to ... Full text Link to item Cite

Single-shot spiral image acquisition with embedded z-shimming for susceptibility signal recovery.

Journal Article J Magn Reson Imaging · September 2003 PURPOSE: To efficiently and effectively recover the susceptibility-induced signal losses for functional MRI (fMRI) experiments. MATERIALS AND METHODS: The signal losses near air/tissue interfaces at the ventral brain regions introduce difficulties in the n ... Full text Link to item Cite

Conflict monitoring in the human anterior cingulate cortex during selective attention to global and local object features.

Journal Article Neuroimage · August 2003 Parallel processing affords the brain many advantages, but processing multiple bits of information simultaneously presents formidable challenges. For example, while one is listening to a speaker at a noisy social gathering, processing irrelevant conversati ... Full text Link to item Cite

Neural mechanisms of top-down control during spatial and feature attention.

Journal Article Neuroimage · July 2003 Theories of visual selective attention posit that both spatial location and nonspatial stimulus features (e.g., color) are elementary dimensions on which top-down attentional control mechanisms can selectively influence visual processing. Neuropsychologica ... Full text Link to item Cite

An improved gridding method for spiral MRI using nonuniform fast Fourier transform.

Journal Article J Magn Reson · June 2003 The algorithm of Liu and Nguyen [IEEE Microw. Guided Wave Lett. 8 (1) (1998) 18; SIAM J. Sci. Comput. 21 (1) (1999) 283] for nonuniform fast Fourier transform (NUFFT) has been extended to two dimensions to reconstruct images using spiral MRI. The new gridd ... Full text Link to item Cite

Faces evoke spatially differentiated patterns of BOLD activation and deactivation.

Journal Article Neuroreport · May 23, 2003 Using fMRI techniques sensitive to blood oxygen-level dependent (BOLD) contrast, we measured brain activity in participants (n=8) as they viewed images of faces presented periodically within a continuously changing montage of common objects. Consistent wit ... Full text Open Access Link to item Cite

Improved spatial localization based on flow-moment-nulled and intra-voxel incoherent motion-weighted fMRI.

Journal Article NMR Biomed · May 2003 Functional MRI signal based on the blood oxygenation level-dependent contrast can reveal brain vascular activities secondary to neuronal activation. It could, however, arise from vascular compartments of all sizes, and in particular, be largely influenced ... Full text Link to item Cite

Magnetic resonance imaging with lateralized arterial spin labeling.

Journal Article Magn Reson Imaging · October 2002 We report the development of a new MRI technique which allows spins from right-sided arteries to be labeled separately from spins from left-sided arteries. This method uses two spatially-selective adiabatic inversion pulses to alternate the labeling of the ... Full text Link to item Cite

Enhanced spatial localization of neuronal activation using simultaneous apparent-diffusion-coefficient and blood-oxygenation functional magnetic resonance imaging.

Journal Article Neuroimage · October 2002 Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to local neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because ... Link to item Cite

BOLD signal compartmentalization based on the apparent diffusion coefficient.

Journal Article Magn Reson Imaging · September 2002 Functional MRI (fMRI) can detect blood oxygenation level dependent (BOLD) hemodynamic responses secondary to neuronal activity. The most commonly used method for detecting fMRI signals is the gradient-echo echo-planar imaging (EPI) technique because of its ... Full text Open Access Link to item Cite

On the timing characteristics of the apparent diffusion coefficient contrast in fMRI.

Journal Article Magn Reson Med · August 2002 For the past 10 years, functional MRI (fMRI) has seen rapid progress in both clinical and basic science research. Most of the imaging techniques are based on the blood oxygenation level-dependent (BOLD) contrast which arises from the field perturbation of ... Full text Link to item Cite

Experience-dependent changes in cerebellar contributions to motor sequence learning.

Journal Article Proc Natl Acad Sci U S A · January 22, 2002 Studies in experimental animals and humans have stressed the role of the cerebellum in motor skill learning. Yet, the relative importance of the cerebellar cortex and deep nuclei, as well as the nature of the dynamic functional changes occurring between th ... Full text Link to item Cite

Functional activation of the extensor carpi radialis muscles in humans.

Journal Article Arch Phys Med Rehabil · September 2001 OBJECTIVES: To assess activity of radial wrist extensors caused by isometric radial deviation and extension by using magnetic resonance imaging (MRI) and to assess measures that might be used to normalize T2-weighted data. DESIGN: Two-way analysis of varia ... Full text Link to item Cite

Single-shot EPI with signal recovery from the susceptibility-induced losses.

Journal Article Magn Reson Med · August 2001 A major problem in the gradient-recalled echo-planar imaging (EPI) method that also uses a long echo time (TE) is the severe signal loss in regions with large static field inhomogeneities. These regions include the ventral frontal, medial temporal, and inf ... Full text Link to item Cite

Lorentz effect imaging.

Journal Article Magn Reson Imaging · July 2001 This paper presents a method that can detect minute electrical activity in a strong magnetic field. It uses displacement encoding to detect small spatial displacement induced by Lorentz force on the conducting materials, hence the term Lorentz effect imagi ... Full text Link to item Cite

Linking sight and sound: fMRI evidence of primary auditory cortex activation during visual word recognition.

Journal Article Brain Lang · March 2001 We describe two studies that used repetition priming paradigms to investigate brain activity during the reading of single words. Functional magnetic resonance images were collected during a visual lexical decision task in which nonword stimuli were manipul ... Full text Link to item Cite

Nonlinear spatiotemporal dynamics of functional MRI revealed by independent components analysis

Journal Article Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings · December 1, 1999 Linear experimental designs have dominated the field of functional neuroimaging, but although successful at mapping regions of relative brain activation, the technique assumes that both cognition and brain activation are linear processes. To test these ass ... Cite

Segmented spin-echo pulses to increase fMRI signal: repeated intrinsic diffusional enhancement.

Journal Article Magn Reson Med · October 1999 Since its inception, functional magnetic resonance imaging (fMRI) has seen rapid progress in the application to neuroscience. Common gradient-recalled acquisition methods are susceptible to static field inhomogeneities, resulting in signal loss at the medi ... Full text Link to item Cite

A confrontational naming task produces congruent increases and decreases in PET and fMRI.

Journal Article Neuroimage · October 1999 This work uses the well-established (by PET) confrontation naming task to compare PET and fMRI in a cognitive activation experiment. The signal changes from this task are much less than the changes caused by visual or motor activation tasks used in previou ... Full text Link to item Cite

Continuous functional magnetic resonance imaging reveals dynamic nonlinearities of "dose-response" curves for finger opposition.

Journal Article J Neurosci · July 15, 1999 Linear experimental designs have dominated the field of functional neuroimaging, but although successful at mapping regions of relative brain activation, the technique assumes that both cognition and brain activation are linear processes. To test these ass ... Full text Link to item Cite

T1-selective diffusion weighted fMRI at 1.5 T

Journal Article NMR Biomed. (UK) · 1998 Apparent diffusion coefficients (ADC) of protons contributing to the functional signal can be determined from diffusion weighted functional magnetic resonance imaging (MRI) studies. An earlier study indicated that ADCs calculated from the functional signal ... Full text Link to item Cite

fMRI and PET studies of a visual confrontation naming task

Journal Article NeuroImage · January 1, 1998 Full text Cite

The effect of off-resonance radiofrequency pulse saturation on fMRI contrast.

Journal Article NMR Biomed · 1997 This paper describes the use of off-resonance saturation to further manipulate the blood oxygenation level dependent (BOLD) contrast of fMRI. A customized narrow bandwidth radiofrequency pulse, applied with a range of frequency offsets prior to selection o ... Full text Link to item Cite

Technical foundations and pitfalls of clinical fMRI.

Journal Article Neuroimage · December 1996 Magnetic resonance imaging (MRI) has become an established and invaluable tool in the diagnosis of numerous diseases through its ability to show pathologic contrast in images of soft tissue. More recently, MRI has found application in the study of organ fu ... Full text Link to item Cite

Diffusion weighted fMRI at 1.5 T.

Journal Article Magn Reson Med · February 1996 Functional magnetic resonance imaging (fMRI) is capable of detecting task-induced blood oxygenation changes using susceptibility sensitive pulse sequences such as gradient-recalled echo-planar imaging (EPI). The local signal increases seen in the time cour ... Full text Link to item Cite

Optimized isotropic diffusion weighting.

Journal Article Magn Reson Med · August 1995 The authors introduce several sets of time-efficient gradient waveforms for applying isotropic diffusion weighting in NMR experiments. This creates signal attenuation that depends on the trace of the diffusion tensor and is therefore rotationally invariant ... Full text Link to item Cite

Echo-volume imaging.

Journal Article Magn Reson Med · November 1994 Two single-shot volume imaging techniques are described. The first, single-echo echo-volume imaging, is essentially the echo-volume imaging (EVI) sequence suggested by Mansfield (J. Phys. C. 10, L55 (1977)). The second is a multi-spin-echo approach in whic ... Full text Link to item Cite