Electronic
Poster Session - fMRI |
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fMRI: Connectivity Analysis & Temporal Characteristics
Click on
to view
the abstract pdf and click on
to view the
video presentation. (Not all presentations are available.)
Monday 7 May 2012
Exhibition Hall |
10:45 - 11:45 |
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Computer # |
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2820. |
49 |
A geometric view of global
signal confounds in resting-state fMRI ![](play.gif)
Thomas Liu1, and Hongjian He2
1UCSD Center for Functional MRI, La Jolla,
CA, United States, 2Bio-X
Laboratory, Zhejiang University, Hangzhou, China
In resting-state functional connectivity MRI (fcMRI),
the presence of global signal confounds lead to
variability in connectivity maps. A number of global
signal correction methods have been proposed, but have
their limitations. Here we demonstrate that a portion of
the global signal can be viewed as an additive confound
that increases with the mean BOLD amplitude. An approach
for minimizing the contribution of this additive
confound is presented, and an initial comparison with
existing global signal correction methods is provided.
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2821. |
50 |
Noise-related variance of
functional networks ![](play.gif)
Hu Cheng1, and Aina Puce1
1Indiana University, Bloomington, IN, United
States
A simple method is proposed to estimate the variance of
resting state functional network originated from
residual noises in the MRI signal. The variance from
noise is compared with the total variance between
networks from different time periods. The results
suggest that a substantial amount of variance of the
functional network comes from the intrinsic noise that
is not coupled with the coherences of different brain
regions. Sampling more time points can effectively
reduce the noise-related variance. Another effect of
residual noise is reduction of the correlation
coefficient, which can be estimated from the variance of
network.
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2822. |
51 |
Identification of state
changes from spontaneous fluctuations in fMRI data
![](play.gif)
Meghan Robinson1, Javier Gonzalez-Castillo1,
Souheil Inati2, Daniel Handwerker1,
and Peter Bandettini1,2
1Section on Functional Imaging Methods, NIMH,
NIH, Bethesda, MD, United States, 2functional
MRI Facility, NIMH, NIH, Bethesda, MD, United States
The brain is continuously adapting to respond to the
environment. In the course of a rest scan, subjects are
expected to engage in different cognitive states for
variable periods of time (i.e., relaxing, planning
dinner, napping, etc.). Each of these states brings the
brain into a different pattern of overall connectivity.
Still, some level of stability is expected for the
periods when subjects remain in a given cognitive state.
Here, we propose a way to automatically identify such
cognitive states looking at how the fMRI signal from
different cortical regions pass in-and-out of synchrony
with each other as time progresses.
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2823. |
52 |
Time-Frequency Dynamics of
Resting State Effective Connectivity in the Default Mode
Network ![](play.gif)
Gopikrishna Deshpande1,2, Hao Jia1,
Zhihao Li3, and Xiaoping Hu3
1AU MRI research center, Dept. of ECE, Auburn
University, Auburn, Alabama, United States, 2Dept.
of Psychology, Auburn University, Auburn, Alabama,
United States, 3Coulter
Dept of Biomedical Engineering, Georgia Institute of
Technology and Emory University, Atlanta, Georgia,
United States
Functional connectivity in resting state networks show
dynamic patterns in time and frequency.We hypothesized
that effective connectivity between resting state fMRI
time series may also dynamically evolve across time and
frequency. We obtained effective connectivity between 33
regions in 4 RSNs as a function of time and frequency
using dynamic multiscale vector autoregressive model
based on Kalman filter. We observed that in the 0.1 to
0.01 Hz frequency range, RSNs toggle between 5 distinct
states.
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2824. |
53 |
Observing Resting-State
Networks at Higher Frequencies with MR-Encephalography and
Independent Component Analysis ![](play.gif)
Hsu-Lei Lee1, Benjamin Zahneisen1,
Thimo Hugger1, Pierre LeVan1, and
Jürgen Hennig1
1Medical Physics, University Medical Center
Freiburg, Freiburg, Germany
MR-Encephalography allows the acquisition of whole brain
volume image within 100 msec. With this high sampling
rate, we looked at resting-state fMRI BOLD signal at
0.5~0.8 Hz. Independent component analysis revealed
several resting-state networks that are similar to the
ones observed under 0.1 Hz. These networks at higher
frequencies are more stable as we shorten the signal
length, therefore can provide the possibility to shorten
total scan time and to assess resting-state network
dynamics over a period of time.
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2825. |
54 |
Unsupervised Parcellation
of Precentral Gyrus using Resting-state fMRI ![](play.gif)
Ali-Mohammad Golestani1, and Mariana Lazar1
1Radiology, New York University Medical
Center, New York, NY, United States
Anatomical landmarks are commonly used to identify
regions of interest (ROIs) for brain imaging studies
that might not reflect functional specialization.
Previous studies showed that some of the anatomically
defined ROIs can be subdivided into sub-regions based on
their connectivity. Most of the parcellation approaches
use clustering algorithms in which the number of
clusters should be known in advance. We used a new
clustering method that estimates the number and size of
sub-regions, and parcellate precentral gyrus into
posterior and inferior parts. This study highlights the
importance of using a parcellation method that can
automatically detect the number of clusters.
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2826. |
55 |
Functional Connectivity
Based Clustering of White Matter ![](play.gif)
Clare Kelly1, Greg J. Siegle2, and
Michael P. Milham3,4
1NYU Child Study Center, New York, NY, United
States, 2University
of Pittsburgh School of Medicine, Pittsburgh, PA, United
States, 3Nathan
S. Kline Institute for Psychiatric Research, NY, United
States, 4Child
Mind Institute, New York, NY, United States
Studies applying clustering methods to intrinsic
(resting-state) functional connectivity (iFC) data have
largely avoided white matter (WM), reflecting skepticism
regarding the fidelity of WM BOLD signal. In light of
mounting evidence supporting the neurophysiological
veracity of WM BOLD, we parcellated WM on the basis of
iFC, using a multi-site large-n dataset. We obtained a
symmetrical topography consistent with DTI tractography
atlases. For example, the corpus callosum, the internal
capsule, and the superior longitudinal fasciculus were
stably identified across sites. We suggest that iFC
measures may have utility for the investigation of WM in
clinical disorders characterized by WM alterations.
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2827. |
56 |
BrainNet Viewer: A
Graph-Based Brain Network Mapping Tool ![](play.gif)
Mingrui Xia1, Jinhui Wang1, and
Yong He1
1State Key Laboratory of Cognitive
Neuroscience and Learning, Beijing Normal University,
Beijing, China
With the development of complex network analyzes on
human brain neuroimaging data; visualization of the
structural and functional connectivity patterns became
an important part of the graph theoretical approach. An
easy using network visualization tool can help
researchers show their results intuitively, and
highlight their key point. Therefore we developed this
brain network visualization tool termed as ‘BrainNet
Viewer’, which can help researchers visualize structural
and functional connectivity patterns from different
levels in a quick, easy and flexible way. This package
can be downloaded from NITRC (www.nitrc.org/projects/bnv/).
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2828. |
57 |
The x-Guided Clustering
Method and its Application to Unbiased Detection of
Differences in Functional Connectivity Networks
![](play.gif)
Gang Chen1, B. Douglas Ward1,
Chunming Xie1, Wenjun Li1, Guangyu
Chen1, Joseph S Goveas2, Piero G
Antuono3, and Shi-Jiang Li1
1Biophysics, Medical College of Wisconsin,
Milwaukee, WI, United States, 2Psychiatry
and Behavioral Medicine, Medical College of Wisconsin,
Milwaukee, WI, United States, 3Neurology,
Medical College of Wisconsin, Milwaukee, WI, United
States
In resting-state functional MRI cross-group studies, the
available techniques may bias the results in choosing
the specified reference. We introduced an x-guided
clustering method to solve this problem. The x-guided
clustering method incorporates all of the subject groups
by producing group difference information and then
creating functional clusters. This method was applied to
identify functional clusters that were significantly
different between the amnestic mild cognitively impaired
and cognitively normal subjects.
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2829. |
58 |
A new information
theoretic approach to quantify fMRI functional connectivity ![](play.gif)
Yinan Liu1, Karl Young1,2, Yu
Zhang1,2, Michael Weiner1,2, and
Norbert Schuff1,2
1Department of Veteran Affairs Medical
Center, Center for Imaging of Neurodegenerative
Diseases, San Francisco, CA, United States, 2Department
of Radiology and Biomedical Imaging, University of
California at San Francisco, San Francisco, CA, United
States
We examined the value of transient information (TI), a
recently introduced information-theoretic quantity that
measures the uncertainty in synchronization, for
characterizing functional connectivity in fMRI.
Specifically, we used TI to capture the process of
synchronization between two fMRI signals whose
periodicity is initially unknown. We found that TI
various markedly across the brain with e.g. posterior
cingulate and precuneus synchronizing easier and faster
with each other than with the putamen. These preliminary
results suggest that TI may be a useful metric for
quantifying functional connectivity.
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2830. |
59 |
A Comparison Study of
CMBHC and ICA Methods for Human Functional Connectivity
Analysis ![](play.gif)
Xiao Liu1, Xiao-Hong Zhu1, and Wei
Chen1
1Radiology, Center for Magnetic Resonance
Research, Minneapolis, MN, United States
In this study, a recently proposed
correlation-matrix-based hierarchical clustering (CMBHC)
method was tested and evaluated using human
resting-state fMRI datasets, and the results were
compared with those obtained using the independent
component analysis (ICA). It was found that the CMBHC
was able not only to extract more coherent patterns than
the ICA, but also to retain a number of weak but
consistent functional connections (e.g.,
cortico-subcortical connections) that were largely
missed by the ICA. The overall results suggest that the
CMBHC could be a powerful tool for analyzing
resting-state fMRI data, especially at the single
subject level.
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2831. |
60 |
A wavelet-based approach
to improve the reproducibility of resting-state fMRI
analysis ![](play.gif)
Shantanu Majumdar1, and David C Zhu1,2
1Department of Radiology, Michigan State
University, East Lansing, Michigan, United States, 2Department
of Psychology, Michigan State University, East Lansing,
Michigan, United States
Resting-state fMRI has shown great potential towards
understanding the spontaneous brain activity at rest in
healthy subjects as well as patients with neurological
disorders. A viable clinical tool requires a high level
of reproducibility. In this work, we investigated
quantitative effects of a wavelet-based analysis of
resting-state fMRI signal to improve the reproducibility
in detecting functionally active brain regions.
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2832.
![](MAGNA25.jpg) |
61 |
Non-linear modulation of
both positive and negative fMRI responses to visual
stimulation by pre-stimulus occipital EEG alpha power ![](play.gif)
Stephen D Mayhew1, Camillo Porcaro2,
Dirk Ostwald3, and Andrew P Bagshaw1
1Birmingham University Imaging Centre, School
of Psychology, University of Birmingham, Birmingham,
West Mids, United Kingdom, 2Institute
of Neuroscience, Newcastle University, Newcastle upon
Tyne, United Kingdom, 3Bernstein
Centre for Computational Neuroscience, Berlin, Germany
We use simultaneous EEG-fMRI to investigate the
relationship between ongoing or "baseline" brain
activity, as indexed by pre-stimulus EEG alpha (8-13Hz)
power, and the magnitude of the BOLD fMRI response to
brief visual stimulation. We report a significant
reduction of visual PBR and enhancement of auditory NBR
in trials preceded by high alpha power, beyond that
predicted by a linear model. This study provides new
evidence that both PBR and NBR to visual stimulation are
nonlinearly dependent upon electrophysiological
characteristics of baseline brain activity and that NBR
reflects inhibition of non-task related brain areas as
indexed by occipital alpha power.
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2833. |
62 |
Analysis of MR Signal
Dynamics during Carbogen Inhalation using a Combined Spin-
And Gradient-Echo (SAGE) EPI Sequence ![](play.gif)
Georges Hankov1, Thomas Christen1,
Heiko Schmiedeskamp1, Roland Bammer1,
and Greg Zaharchuk1
1Department of Radiology, Stanford
University, Stanford, California, United States
The purpose of the study was to follow and analyze the
dynamic changes in brain oxygenation induced by a
carbogen respiratory challenge in normal human brain.
Using a simple model and a multiple spin- and
gradient-echo (SAGE) EPI sequence, maps of amplitude,
wash-in and wash-out time constants, and arrival time
delay of carbogen were computed. In 5 volunteers, we
found a homogeneous response to carbogen and low
inter-subject variability. This methodology could be
used to study pathologies such as stroke or cancer.
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2834. |
63 |
The Contribution of
Vascular Reactivity in Layer-Specific Hemodynamic Response ![](play.gif)
Cecil Chern-Chyi Yen1, Fuqiang Zhao2,
and Seong-Gi Kim3,4
1National Institute of Neurological Disorders
and Stroke, National Institutes of Health, Bethesda, MD,
United States, 2Imaging,
Merck, West Point, PA, United States, 3Radiology,
University of Pittsburgh, Pittsburgh, PA, United States, 4Bioengineering,
University of Pittsburgh, Pittsburgh, PA, United States
Cortical layer-specific responses are shown to resemble
the neural response of the cortical layers. However,
these layer-specific hemodynamic responses may be
contaminated by the vascular reactivity, which is known
to have layer-specific distribution. To investigate this
issue, we performed two cerebral blood volume (CBV)-
weighted fMRI studies in cat visual cortex with
hypercapnic stimulus as an indicator for vascular
reactivity, and visual stimulus. Our results showed that
the peak responses of the CBV-weighted layer profile
induced by hypercapnic stimulus co-localized with that
induced by visual stimulus. Therefore, cautions shall be
taken in interpreting layer-specific hemodynamic
response as neural response.
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2835. |
64 |
Specificity and
Sensitivity of Layer specific fMRI responses using GE and 3D
GRASE at high fields. ![](play.gif)
Federico De Martino1,2, Jan Zimmermann2,
Lars Muckli3, Kamil Ugurbil1,
Pierre-Francois van de Moortele1, Rainer
Goebel2, and Essa Yacoub1
1Radiology, Center for Magnetic Resonance
Research, Minneapolis, Minnesota, United States, 2Cognitive
Neuroscience, Maastricht University, Maastricht,
Netherlands, 3Psychology,
University of Glasgow, GLasgow, United Kingdom
Laminar specific fMRI in humans has potential for
clinical applications. It has not yet been demonstrated
whether gains in high field T2 weighted BOLD would be
advantageous in layer specific fMRI investigations
and/or in regions outside of V1. We examine layer
specific response profiles in two different visual areas
(V1 and MT) within the same subjects and compare
Gradient Echo and GRASE. We show that GRASE might be
preferred to GE when layer specific responses throughout
the entire cortical depth are of interest.
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2836. |
65 |
An assessment of the
post-stimulus undershoot using hyperoxic BOLD contrast and
ASL ![](play.gif)
Ian D Driver1, Emma L Hall1, Paula
L Croal1, Susan T Francis1, and
Penny A Gowland1
1Sir Peter Mansfield Magnetic Resonance
Centre, University of Nottingham, Nottingham, United
Kingdom
The BOLD post-stimulus undershoot (PSU) following a
motor task is assessed at 7T through simultaneous
measurement of BOLD, CBF, and venous CBV using hyperoxia.
This work shows a post-stimulus undershoot in both the
BOLD and CBF response, when the venous CBV response had
returned to baseline. This suggests a neuronal origin
for the PSU, but could also result from a delayed
vascular compliance. Results show that at the spatial
resolution (2 x 2 x 3 mm3), the PSU is not
more localised to the underlying neuronal response, as
reported in animal models.
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2837. |
66 |
Dynamic
compartment-specific cerebral blood volume and BOLD
responses to electrical forepaw stimulation in -chloralose
anesthetized rats
![](play.gif)
Xiaopeng Zong1, Tae Kim1, and
Seong-Gi Kim1
1Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, United States
Studying the compartment-specific dynamic cerebral blood
volume responses is important for quantitative fMRI
studies and understanding the dynamic properties of BOLD
fMRI responses. In this study, we measured BOLD,
arterial ( ![Capital Greek Delta](http://submissions.miracd.com/ISMRM2012/Images/UCGreek/Delta.gif) CBV a),
venous ( ![Capital Greek Delta](http://submissions.miracd.com/ISMRM2012/Images/UCGreek/Delta.gif) CBV v),
and total cerebral blood volume responses to electrical
forepaw stimulation in ![lower case Greek alpha](http://submissions.miracd.com/ISMRM2012/Images/LCGreek/alpha.gif) -chloralose
anesthetized rats using a magnetization transfer-varied
fMRI technique and injection of paramagnetic contrast
agent. We found a fast ![Capital Greek Delta](http://submissions.miracd.com/ISMRM2012/Images/UCGreek/Delta.gif) CBV a response
and a delayed slower ![Capital Greek Delta](http://submissions.miracd.com/ISMRM2012/Images/UCGreek/Delta.gif) CBV v response.
Our findings are consistent with earlier studies under
different anesthesia conditions and support the
anesthesia independence of the fast CBV a and
slow CBV v dynamic
properties.
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2838. |
67 |
Dynamics of BOLD fMRI time
series: dependence on cognitive load and sensitivity to
temporal pre-processing
![](play.gif)
Catie Chang1, Biyu J. He2, and
Jeff H. Duyn1
1Advanced MRI section, NINDS, National
Institutes of Health, Bethesda, MD, United States, 2NINDS,
National Institutes of Health, Bethesda, MD, United
States
It was recently demonstrated that the BOLD signal
exhibits scale-free temporal dynamics whose
autocorrelation/long-range memory is reflected in the
Hurst exponent (H). Here, we demonstrate that H and BOLD
signal amplitude decrease as a function of increased
cognitive effort (working memory load) across widespread
regions of the brain. Furthermore, we characterize the
sensitivity of H to the manner in which fMRI data are
pre-processed. Importantly, removing noise due to
physiological processes and head motion was found to
enhance the significance of load-dependent changes in
the Hurst exponent, increasing the likelihood that the
observed dynamic changes are of neural origin.
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2839.
![](MAGNA25.jpg) |
68 |
Microvascular GE BOLD
specificity and dynamics revealed by ultra high field MRI in
humans ![](play.gif)
Jeroen C. W. Siero1,2, Nick F. Ramsey1,
Hans Hoogduin1,2, Dennis W. J. Klomp2,
Peter R. Luijten2, and Natalia Petridou1,2
1Rudolf Magnus Institute, University Medical
Center Utrecht, Utrecht, Utrecht, Netherlands, 2Radiology,
University Medical Center Utrecht, Utrecht, Utrecht,
Netherlands
Gradient-echo BOLD at high fields has opened up the
possibility to visualize the cortical columnar and
laminar functional organization but its specificity can
suffer from contributions of several vessel sizes even
at high fields. Here we assess the microvascular
contributions of the GE BOLD response (HRF) across the
cortical depth at 7T by relating it to the microvascular
specific SE BOLD response. We show that the early phase
(onset time and rising slope) of the GE HRF is specific
to the microvasculature in deep gray matter which
presumably contains layers III-V.
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2840. |
69 |
Temporal Characteristics
of the Homodynamic Response Function of Transition-band SSFP
fMRI
![](play.gif)
Jing Chen1, Jing An2, Yan Zhuo1,
and X. Joe Zhou3
1State Key Laboratory of Brain and Cognitive
Science, Inst. of Biophysics, Chinese Academy of
Sciences, Beijing, China, 2MR
Collaboration NE Asia, Siemens Healthcare, Siemens
Shenzhen Magnetic Resonance, Shenzhen, China, 3Department
of Radiology and Center for MR Research, University of
Illinois Medical Center, Chicago, IL, United States
Recently, steady-state free precession (SSFP) fMRI has
drawn widespread interests, due to its unique ability of
providing distortion-free functional images with
improved SNR/CNR, especially in regions near
susceptibility boundaries. However, to develop SSFP fMRI
as a robust tool for a broad range of applications,
several practical issues must be carefully examined. In
this study, we measure the hemodynamic response function
of transition-band SSFP (tb-SSFP) fMRI, describe its
temporal characteristics, and evaluate its linearity.
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2841. |
70 |
Comparison of
Methodologies for Detecting Small Temporal Differences in
BOLD Responses Using fMRI ![](play.gif)
Santosh B. Katwal1,2, John C. Gore2,3,
and Baxter P. Rogers2,3
1Electrical Engineering and Computer Science,
Vanderbilt University, Nashville, TN, United States, 2Vanderbilt
University Institute of Imaging Science, Nashville, TN,
United States, 3Biomedical
Engineering, Vanderbilt University
We assessed the ability to detect small temporal
differences in BOLD responses from fMRI using Granger
causality. Task-related-voxels were selected using: i)
self-organizing map (SOM), ii) independent component
analysis (ICA), iii) statistical parametric mapping
(SPM) and iv) localizer scan in conjunction with SPM.
Additionally, we fitted curves to average signals with
inverse logit functions and estimated the differences in
time-to-peak to compare the temporal differences. The
combination of SOM and Granger causality detected
differences as small as 28 ms. In general, data-driven
approach for voxel selection seems to work better than
hypothesis-driven approach in detecting small temporal
differences from fMRI.
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2842. |
71 |
Identification of
Spatio-Temporal Oscillatory Signal Structure in Cerebral
Hemodynamics Using DRIFTER ![](play.gif)
Simo Särkkä1, Arno Solin1, Aapo
Nummenmaa1,2, Aki Vehtari1, Toni
Auranen3, Simo Vanni3,4, and
Fa-Hsuan Lin1,2
1Department of Biomedical Engineering and
Computational Science, Aalto University, Espoo, Finland, 2Athinoula
A. Martinos Center for Biomedical Imaging, Massachusetts
General Hospital, Boston, MA, United States, 3Advanced
Magnetic Imaging Centre, Aalto University, Espoo,
Finland, 4Low
Temperature Laboratory, Aalto University, Espoo, Finland
We use a Kalman filter and smoother method (DRIFTER) to
identify physiological oscillatory signals from fMRI
data, and analyze their spatial amplitude and phase
structures. The frequencies of the cardiac and
respiration signals were identified from external
reference signals and the frequency of a physiological
0.1 Hz signal was identified from spatially averaged EPI
data with 100 ms TR. The results indicate that the
signals indeed have a clear spatial structure, which
could be used to aid removal of the physiological
signals or for analysis of brain functionality.
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2843. |
72 |
Correlated Slow
Fluctuations in Respiration, EEG, and BOLD fMRI: What is the
Origin of Physiological Noise?
Han Yuan1, Vadim Zotev1, Raquel
Phillips1, and Jerzy Bodurka1
1Laureate Institute for Brain Research,
Tulsa, OK, United States
We investigated the relationship between the
respiration, alpha-band-limited EEG power, and BOLD fMRI
from simultaneous recordings in human subjects and have
found significant correlation between slow temporal
fluctuations of these three sources of signals. In
particular, the correlation between respiration and EEG
is much stronger in closed-eye resting than in open-eye
resting, and is consistently observed from recordings
inside and outside scanner. Results suggest that
respiration fluctuations reflect and are linked to the
underlying brain electrophysiological activity.
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Electronic
Poster Session - fMRI |
|
fMRI: Analysis & High-Resolution Methods
Click on
to view
the abstract pdf and click on
to view the
video presentation. (Not all presentations are available.)
Monday 7 May 2012
Exhibition Hall |
11:45 - 12:45 |
|
|
|
Computer # |
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2844.
![](MAGNA25.jpg) |
49 |
Approximate entropy as a
metric for quantifying fMRI changes across time
![](play.gif)
Kyle D Steinke1, David Frakes2,
Jose Rios3, Gabe Oland2, and
Leslie C Baxter1
1Neuroimaging Research, Barrow Neurological
Institute, Phoenix, AZ, United States, 2School
of Biological and Health Systems Engineering, Arizona
State University, Tempe, AZ, United States, 3Biomedical
Engineering, Cornell University, Ithaca, NY, United
States
Functional MRI is of limited utility in longitudinal
studies because it lacks a quantitative baseline. We
tested whether a test of interest (e.g., a motor task)
could be compared to a generally stable vision task to
overcome this weakness. We used approximate entropy (ApEn)
to characterize each time series signal. The motor task
ApEn was then compared to the vision task ApEn to form a
ratio, which remained stable after a caffeine
intervention, as expected, but changed in surgical
patients that had behavioral decline.
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2845. |
50 |
A model of
dopamine-induced fMRI response informed by simultaneous PET/fMRI ![](play.gif)
Joseph Mandeville1, Christin Sander2,
Bruce Jenkins3, Bruce Rosen3,
Jacob Hooker3, Ciprian Catana3,
Wim Vanduffel3, Nathaniel Alpert3,
and Marc Normandin4
1Radiology, Massachusetts General Hospital,
Boston, MA, United States, 2Massachusetts
Institute of Technology, United States, 3Radiology,
Massachusetts General Hospital, United States, 4Massachusetts
General Hospital, United States
fMRI data in an awake monkey during amphetamine
challenge were acquired simultaneously with PET
measurement of D2 receptor density. A compartment model
of the fMRI response, based upon the competing effects
of stimulation at D1 and D2 receptors, was developed to
describe the temporal shape and magnitude of the fMRI
response, while also accurately describing other
reported fMRI responses in monkeys and rats at different
levels of drug-induced dopamine. The model-inferred D2
contribution to fMRI signal correlated linearly with
measured D2 receptor density. Simultaneous PET/MR
measurements of dynamic dopaminergic function will be
required to further refine the model.
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2846. |
51 |
Consistent Activation
Across Trials and Field Strengths by ROC-reproducibility
Thresholding ![](play.gif)
Tynan Reid Stevens1, David B Clarke2,
Ryan CN D'Arcy1, and Steven D Beyea1
1IBD-Atlantic, NRC, Halifax, Nova Scotia,
Canada, 2QEII
Health Science Centre, Halifax, Nova Scotia, Canada
Setting activation thresholds remains a significant
challenge in fMRI. Fixed threshold levels do not account
for individual variability, habituation, or acquisition
strategies. We developed a method for determining
data-driven thresholds levels based on test-retest
ROC-reproducibility (ROC-r) analysis. Eight subjects
performed test-retest fMRI at two field strengths (1.5 &
4 Tesla). Optimized ROC-r thresholds were calculated for
the template (5.27 +/- 0.22) and retest images (3.71 +/-
0.18). The ROC-r thresholds were significantly higher
for 4 Tesla than 1.5 Tesla. Compared to FDR or
Bonferroni thresholds, ROC-r thresholds produced more
consistent activation extent across field strengths and
trials.
|
2847. |
52 |
fMRI Motion Regressors
Based on EEG Motion Artifacts in Simultaneous EEG-fMRI
Vadim Zotev1, Han Yuan1, Raquel
Phillips1, and Jerzy Bodurka1
1Laureate Institute for Brain Research,
Tulsa, OK, United States
EEG performed simultaneously with fMRI with millisecond
temporal resolution is particularly sensitive to rapid
head rotations. Motion artifacts in EEG-fMRI recordings
contain useful real-time information about such
rotations. We describe a novel and simple approach for
deriving additional fMRI motion regressors directly from
EEG motion artifacts, and demonstrate its efficiency for
patients with major depression. We show that inclusion
of four EEG based motion regressors to the GLM model in
addition to six fMRI motion parameters reduces average
standard deviation of the GLM fit error by 5-10%,
especially in frontal and occipital regions. Possible
applications of this approach are discussed.
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2848. |
53 |
Removal of
ballistocardiographic artifacts from EEG recorded inside the
MR scanner using an optical motion-tracking system ![](play.gif)
Pierre LeVan1, Julian Maclaren1,
Michael Herbst1, and Jürgen Hennig1
1Radiology, Medical Physics, University
Medical Center Freiburg, Freiburg, Germany
This study investigates the use of accurate
motion-tracking to remove ballistocardiographic (BCG)
artifacts in EEG recorded inside the MR scanner. These
artifacts, due to heartbeat-related head motion in the
magnetic field, are usually corrected by an averaged
artifact subtraction (AAS) method, which consists of
subtracting a template formed by averaging EEG signals
from each cardiac cycle. However, AAS cannot model
artifact variability across cardiac cycles, preventing a
complete removal of BCG artifacts. Motion measurements
during scanning were used to regress out residual BCG
waveforms, resulting in significantly reduced
root-mean-square residuals across cardiac cycles and
improved EEG quality.
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2849. |
54 |
Correction for T1 effect
incorporating flip angle estimated by Kalman filter in
cardiac-gated fMRI ![](play.gif)
Jaemin Shin1, and Xiaoping Hu1
1Biomedical Engineering, Georgia Tech/Emory
University, Atlanta, GA, United States
To overcome cardiac pulsation related artifact,
cardiac-gated acquisition has been utilized with
correction for T1 effect due to variation of the cardiac
cycle but it is only valid for the flip angle of 90°. B1
inhomogeneity can often cause a significant variation in
flip angle, e.g., 65° to 105° over the brain volume for
a nominal flip angle of 90° at 3 T. In this work, we
developed a generalized correction technique for T1
effect incorporating actual flip angle, estimated from
fMRI dataset itself using Unscented Kalman filter. The
new technique is demonstrated with simulated data and in
vivo data.
|
2850. |
55 |
Removal of synergistic
physiological motion and image artefacts in functional MRI
of the human spinal cord ![](play.gif)
Patrick W Stroman1, Rachael L Bosma1,
Michaela Beynon1, and Christine Dobek1
1Centre for Neuroscience Studies, Queen's
University, Kingston, Ontario, Canada
An improvement in physiological noise removal in spinal
cord fMRI data is demonstrated. A combination of phase
errors due to flow of cerebrospinal fluid (CSF), and
image artefacts at high intensity boundaries between CSF
and adjacent tissues, is revealed by means of computer
simulations of the spinal fMRI acquisition. Spatially
and temporally variant signals are demonstrated that do
not match the timing of the CSF flow itself. However,
the cause of this physiological noise enables it to be
modeled as a convolution of a distortion operator, and
the unaffected data, and we demonstrate a means of
modeling and removing it.
|
2851. |
56 |
Regressor Selection for
RETROICOR and RETROKCOR Corrections of 3D FMRI Data
![](play.gif)
Rob H.N. Tijssen1,2, Mark Jenkinson1,
and Karla L. Miller1
1FMRIB Centre, Oxford University, Oxford,
United Kingdom, 2University
Medical Center Utrecht, Utrecht, Netherlands
In this work we explore the use of retrospective
corrections, in order to remove temporal instabilities
from 3D FMRI acquisitions. Using the Bayesian
Information Criterion (BIC) to determine an optimal
subset, previously proposed for RETROICOR, we aim to
optimize the regressor set for various 3D acquisition
methods (e.g., SPGR and bSSFP). The results suggest that
the optimal number of regressors is highly dependent on
the acquisition and can even be zero (i.e., no
retrospective correction) in some cases (e.g., when a
real-time cardiac synchronized readout is used to
correct for cardiac fluctuations prospectively).
|
2852. |
57 |
Cost-effective fMRI
normalization improves differentiation between subject
categories: the first clinical demonstration ![](play.gif)
Peiying Liu1, Carolyn Sacco2, Yan
Fang2, Carol Tamminga2, and
Hanzhang Lu1
1Advanced Imaging Research Center, University
of Texas Southwestern Medical Center, Dallas, Texas,
United States, 2Department
of Psychiatry, University of Texas Southwestern Medical
Center, Dallas, Texas, United States
The power of fMRI in assessing neural activity and
detecting group differences are often hampered by
variations in fMRI responses across individuals.
Normalization of fMRI signals with basal physiologic
parameters may be useful in reducing variations and
improving sensitivity, but this utility hasn’t been
tested in patient populations. The present work extends
previous findings in healthy controls, and showed a
modulation effect of baseline venous oxygenation on fMRI
signals in Schizophrenia patients. The results
demonstrated that, by accounting for basal physiologic
parameters, the sensitivity of fMRI in differentiating
patient population from healthy controls can be enhanced
with relatively little cost.
|
2853. |
58 |
A real-time fMRI
communication interface for Turbo-BrainVoyager 3.0 using the
TBV 3.0 Plugin Interface
Michael Lührs1, Charles Müller1,
and Johannes Bernarding1
1Department of Biometry and Medical
Informatics, Otto von Guericke University Magdeburg,
Magdeburg, Saxony-Anhalt, Germany
Real-time fMRI communication interface between Turbo-BrainVoyager
3.0 and other software tools, providing transfer of
multiple data (ROI's) and datatypes based on the TCP/IP
protocol.
|
2854. |
59 |
Single trial
classification of complex hand movements using high field
fMRI ![](play.gif)
M.G. Bleichner1, J. M. Jansma1, M.
Raemakers1, J. Sellmeijer1, E.J.
Aarnoutse1, J.C.W. Siero2, N.
Petridou2, and N.F. Ramsey1
1Dept. of Neurology and Neurosurgery,
University Medical Center Utrecht, Rudolf Magnus
Institute of Neuroscience, Utrecht, Netherlands, 2Dept.
of Radiology, University Medical Center Utrecht, Rudolf
Magnus Institute of Neuroscience, Utrecht, Netherlands
Decoding the neuronal activity of complex hand gestures,
as used in sign languages, could be an interesting way
to control a brain computer interface. Thinking about
hand gestures representing letters could be translated
directly into text on a computer screen. Here we study
the underlying neuro-physiological changes of executed
hand movements using high field fMRI. We show that
single trial classification is possible and that
different hand gestures can be distinguished based on
the underlying neuronal activation pattern. We conclude
that complex hand gestures are a promising control
signal for brain computer interfaces.
|
2855. |
60 |
Composite Hypothesis
Testing via Support Vector Regression ![](play.gif)
Nagesh Adluru1, Richard J. Davidson1,
and Andrew L. Alexander1
1University of Wisconsin-Madison, Madison,
WI, United States
Hypothesis testing is one of the most commonly performed
statistical analyses in neuroimaging studies. Often the
goal is to study the effects of variables such as
physiological, behavioral and/or clinical on a variety
of neuroimaging measurements e.g., cortical thickness,
bold-activation, microstructural properties. A most
common approach to test the significance of these
effects is to project the measured neuroimaging data
onto the linear models defined using the variables of
interest via ordinary least squares. In this paper we
propose that using a more robust projection can increase
sensitivity to the effects and hence can also control
for confounding parameters.
|
2856. |
61 |
Enhancement of Temporal
Resolution and BOLD Sensitivity in Real-Time fMRI using
Multi-Slab Echo-Volumar Imaging
![](play.gif)
Stefan Posse1,2, and Elena Ackley1
1Neurology, University of New Mexico,
Albuquerque, NM, United States, 2Electrical
and Computer Engineering, Physics and Astronomy,
University of New Mexico, Albuquerque, NM, United States
Real-time fMRI using multi-slab echo volumar imaging was
performed with temporal resolution of 286 ms for whole
brain acquisition and 136 ms for partial brain
acquisition on a clinical 3 Tesla MRI scanner equipped
with 12-channel head coil. Whole brain EVI with 286 ms
temporal resolution of visual and motor tasks
significantly increased average and maximum percent BOLD
signal change, average and maximum t-score, and extent
of activation compared with EPI. Partial brain EVI with
136 ms temporal resolution exhibited comparable percent
signal change, enabled nonaliased detection of heartbeat
correlated signal fluctuation and improved sampling of
the hemodynamic response function.
|
2857.
![](MAGNA25.jpg) |
62 |
Multiplexed spiral
sequence for high temporal resolution resting state fMRI ![](play.gif)
Benedikt Andreas Poser1, and V Andrew Stenger1
1UH-QMC Neuroscience and MR Research Program,
University of Hawaii, Honolulu, Hawaii, United States
There is demand for shorter whole-brain fMRI acquisition
times to allow clear separation of signals from resting
state networks and unwanted phsysiological fluctuations
(e.g. motion, respiratory and cardiac noise).
“Multiplexed” 2D EPI has been proposed to improve
temporal resolution. We investigate multiplexed
spiral-in acquisition as a more efficent approach
because TE is at the end of the sequence. Factor three
multiplexing gave whole brain coverage with 36 slices in
420ms. RS fMRI at 3T showed clear sampling of
physiologcial noise in the time courses.
|
2858. |
63 |
Increased temporal
resolution in fMRI using Hadamard-encoding with phase
correction and physiological noise removal ![](play.gif)
Alan Chu1, Jon-Fredrik Nielsen1,
and Douglas C. Noll1
1Biomedical Engineering, University of
Michigan, Ann Arbor, Michigan, United States
Hadamard-encoded fMRI is a multi-slice acquisition
method that potentially increases temporal resolution
compared to conventional, single-slice fMRI. Because
Hadamard-encoded fMRI is relatively more susceptible to
signal variations from both physiological and
non-physiological sources, it is critical to perform
appropriate noise removal for the method to perform
well. In this abstract, we outline the proper processing
needed for Hadamard-encoded fMRI, and show that the
results have increased temporal resolution without a
decrease in activation quality.
|
2859. |
64 |
High temporal resolution
fMRI-study of trial-by-trial brain function in Visual
attention
![](play.gif)
Mehdi Ordikhani-Seyedlar1, Benjamin Zahneisen1,
Thimo Hugger1, Jürgen Hennig1, and
Pierre LeVan1
1Radiology and Medical Physics,
University-Medical Center Freiburg, Freiburg, Germany
Our aim was to use a new technique to acquire the whole
brain functional imaging data at a high temporal
resolution of 100ms while doing a visuospatial attention
task. This study showed that high temporal resolution
fMRI can successfully measure small fluctuations in
trial-by-trial BOLD signal correlated with reaction time
in order to identify the emergence of functional
networks in the brain during the execution of a
cognitive task.
|
2860. |
65 |
Comparison of Simultaneous
Multiband Whole Brain Imaging with Multiplexed-EPI ![](play.gif)
Liyong Chen1,2, Audrey Chang1,2,
Junqian Xu3, Steen Moeller3,
Edward J Auerbach3, An Thanh Vu1,2,
Kamil Ugurbil3, Essa Yacoub3, and
David Feinberg1,2
1Helen Wills Neuroscience Institute,
University of California, Berkeley, CA, United States, 2Advanced
MRI Technologies, Sebastopol, CA, United States,3Center
for Magnetic Resonance Research (CMRR), Department of
Radiology, University of Minnesota, Minneapolis, MN,
United States
Multiplexed-EPI is performed using different number of
images readout simultaneous in the EPI echo trains.
Compared in whole brain imaging, slice accelerations (M)
of 6 to 48 images per echo train were evaluated. Results
showed observable trade-offs in image quality at highest
accelerations using single echo trains to scan the whole
brain and good quality images using two or three echo
trains.
|
2861. |
66 |
Investigating the
performance of ZOOM-EPI for fMRI in the brain ![](play.gif)
Moreno Pasin1, Marios C Yiannakas1,
Ahmed Toosy2, and Claudia A M
Wheeler-Kingshott1
1NMR Research Unit, Department of
Neuroinflammation, UCL Institute of Neurology,
University College London, London, England, United
Kingdom, 2NMR
Unit, Department of Brain Repair and Rehabilitation, UCL
Institute of Neurology, University College London,
London, United Kingdom
In this study we assess the performance of the
ZOnally-magnified Oblique Multislice EPI (ZOOM-EPI)
sequence using a reduced field of view for targeted
areas of fMRI activation. We compared motor fMRI
activations on 5 healthy subjects obtained using
ZOOM-EPI with ones obtained using conventional GE-EPI
and SE-EPI sequences in terms of their spatial
localisation. Moreover we report the dimensions of the
activated regions in each subject for the three
different sequences. For all subjects the ZOOM-EPI
showed good anatomical correspondence with the
overlapping activated areas from the more conventional
GE-EPI and SE-EPI sequences and more localised
activation.
|
2862. |
67 |
Submillimeter fMRI at 3T
using Long Axis PROPELLER-EPI ![](play.gif)
Martin Krämer1, and Jürgen R Reichenbach1
1Medical Physics Group, Department of
Diagnostic and Interventional Radiology I, Jena
University Hospital, Jena, Germany
Using the PROPELLER-EPI technique for functional
magnetic resonance imaging has the advantage that,
albeit the multi-shot nature of the method, acceptable
temporal resolutions can be achieved. At the same time
the readout train length is significantly reduced,
enabling high in-plane resolutions. In our work we
demonstrate that long-axis PROPELLER-EPI can be used for
performing fMRI with submillimeter resolution at a
clinical field strength of 3T. Results from a finger
tapping experiment are presented with an in-plane
resolution of 0.7 mm2
|
2863. |
68 |
High-resolution fMRI
experiments on visual cortex using consecutive interleaved
EPI at 7T ![](play.gif)
Dae-Hun Kang1, Uk-Su Choi1,
Jun-Young Chung1, Da-Eun Kim1,
Young-Bo Kim1, and Zang-Hee Cho1
1Neuroscience Research Institute, Gachon
University of Medicine and Science, Incheon, Korea
Using consecutive interleaved multi-shot EPI scheme (ciEPI)
with minimal intersegment delay and parallel imaging is
one of methods to obtain less-distorted images.
Recently, multiple stimulus-driven retinotopic maps were
introduced using conventional EPI schemes in the
previous study. In a present paper, a retinotopic
response is observed by visual stimuli through ciEPI
schemes with high-resolution at 7T.
|
2864. |
69 |
High temporal resolution
and physiological noise removal improve BOLD detection in
brainstem and auditory cortex at 7T ![](play.gif)
Wietske van der Zwaag1,2, Mayur Narsude1,
João Jorge3, José Pedro Marques1,2,
and Rolf Gruetter1,2
1Université de Lausanne, Lausanne, VD,
Switzerland, 2LIFMET,
EPFL, Lausanne, VD, Switzerland, 3Instituto
Superior Técnico, Lisbonne, Switzerland
Physiological noise can prohibit the detection of BOLD
signal variations. The movement of the brainstem during
the cardiac cycle amplifies this problem locally. In
this study, the effect of (1) temporal resolution of a
3D-EPI acquisition and (2) physiological noise removal
on BOLD detection in primary auditory cortex AI and the
brainstem were investigated. Physiological noise removal
was essential for BOLD signal detection in the brainstem
at the axial slice orientation used. In addition, higher
temporal resolution increased the number of active
voxels significantly. Increases in BOLD sensitivity with
shorter TR and physiological noise removal were also
found in AI.
|
2865. |
70 |
High-resolution
sparse-sampling fMRI reveals tonotopic organization of human
inferior colliculus
![](play.gif)
David Ress1, Reswanul Khan2,
Bharath Chandresekaran3, and Seth Koslov3
1Neurobiology, Psychology, Imaging Research
Center, Center for Perceptual Systems, The University of
Texas at Austin, Austin, TX, United States,2Neurobiology,
Physics, Imaging Research Center, Center for Perceptual
Systems, The University of Texas at Austin, Austin, TX,
United States,3Communication Sciences and
Disorders, The University of Texas at Austin, Austin,
TX, United States
We present a high-resolution sparse-sampling fMRI
approach for imaging small auditory brainstem
structures. High resolution is obtained with a
multi-shot spiral acquisition. Sparse sampling is
obtained by two adjustments to the fMRI pulse sequence.
First, quiet periods are created by disabling the
acquisition gradients for long periods (9 s) to permit
delivery of auditory stimuli. Second T1-equilibrium is
maintained by continual delivery of slice-selective
excitation pulses throughout each scanning run. Using
this approach, we have obtained 1.2-mm sampling in human
inferior colliculus (IC) with satisfactory
contrast-to-noise ratio. The data confirm a laminar
organization of stimulus frequency representation in
human IC.
|
2866. |
71 |
Depth characterization of
the BOLD hemodynamic response function in human early visual
cortex
![](play.gif)
Reswanul Khan1, Sucharit Katyal2,
Clint Greene2, Evan Luther3, and
David Ress2
1Neurobiology, Physics, Imaging Research
Center, Center for Perceptual Systems, The University of
Texas at Austin, Austin, TX, United States,2Neurobiology,
Psychology, Imaging Research Center, Center for
Perceptual Systems, The University of Texas at Austin,
Austin, TX, United States,3Neurobiology,
Biomedical Engineering, Imaging Research Center, Center
for Perceptual Systems, The University of Texas at
Austin, Austin, TX, United States
At conventional resolutions, BOLD fMRI samples responses
from various tissues in cerebral cortex: white matter,
gray matter, and extra-pial. Here, we utilize
high-resolution fMRI (0.9-mm voxels) to characterize the
BOLD hemodynamic response function (HRF), as it varies
with depth and tissue type in cortex. Surface-based
analysis methods create a normalized depth coordinate
that permits characterization throughout the variable
thickness of gray matter. The HRF peak response occurs
faster in deep gray matter, but is stronger and noisier
in more superficial tissue. No significant initial dip
is present in the gray matter, but is clearly evident in
extra-pial tissues.
|
2867. |
72 |
Columnar organization or
noise? Optimization and validation of fMRI at the resolution
of columns ![](play.gif)
Denis Chaimow1,2, Kamil Ugurbil1,
and Amir Shmuel1,3
1Center for Magnetic Resonance Research,
University of Minnesota, Minneapolis, MN, United States, 2Max
Planck Institute for Biological Cybernetics, Tübingen,
Germany, 3Montreal
Neurological Institute, McGill University, Montreal, QC,
Canada
The ability of high-field fMRI to truly resolve columnar
organization depends on the spatial scale of the
pattern, the BOLD point spread, the voxel size and the
noise level. To better understand the role of each
factor, and to guide the selection of optimal
parameters, we developed a mathematical model of imaging
cortical columns. We quantified the expected
differential functional contrast relative to noise and
the expected similarity between the imaged pattern and
the true columnar organization as a function of
parameters of interest. We found that the voxel width
that optimizes differential contrast is larger than the
one that optimizes accuracy. Furthermore, we propose a
method for confirming that an imaged pattern reflects
the true columnar organization.
|
|
|
Electronic
Poster Session - fMRI |
|
fMRI: Connectivity Analysis & Novel Contrasts
Click on
to view
the abstract pdf and click on
to view the
video presentation. (Not all presentations are available.)
Monday 7 May 2012
Exhibition Hall |
10:45 - 11:45 |
|
|
|
Computer # |
|
2868. |
73 |
Reduced Local BOLD
Correlation in Pre-Frontal Cortex during Deep Sleep
![](play.gif)
Xiao Liu1, Silvina G. Horovitz1,2,
Allen R. Braun3, Walter S. Carr4,
Dante Picchionie5, Masaki Fukunaga1,
and Jeff H. Duyn1
1Advanced MRI section, LFMI, NINDS, National
Institutes of Health, Bethesda, MD, United States, 2Human
Motor Control Section, MNB, National Institutes of
Health, 3Language
Section, Voice, Speech and Language Branch, NIDCD,
National Institutes of Health, 4Naval
Medical Research Center, 5Department
of Behavioral Biology, Walter Reed Army Institute of
Research
In this study, the average temporal correlation of
spontaneous BOLD fMRI activity within local brain
regions was computed and compared between the wake and
slow wave sleep (SWS) stages in human. Significant
reductions in local BOLD correlation were primarily
found in the prefrontal cortex during the SWS, while
increases were limited to posterior brain regions. The
finding is consistent with the notion that prefontal
activity is an important constituent of higher cognitive
function during conscious awareness, and the fact that
the latter is reduced during SWS. This suggests that the
distribution of local correlation may report on
cognitive state.
|
2869. |
74 |
Disturbed Coherence of
Information Processes as Revealed by Intrinsic Functional
Connectivity during Propofol Anesthesia ![](play.gif)
Maolin Qiu1, Ramachandran Ramani2,
and R. Todd Constable1,3
1Diagnostic Radiology, Yale University, New
Haven, CT, United States, 2Anesthesiology,
Yale University, New Haven, CT, United States, 3Biomedical
Engineering, and Neurosurgery, Yale University
Process-coherence theories have been proposed by
anesthesiologists about anesthesia and unconsciousness
and they were originally based on clinical observations
of neuronal activity in sleep, epileptic, or vegetative
patients. It has been difficult to test hypotheses
involving disruptions in the coherence of neural
activity until very recently with the development of
techniques for reliably assessing intrinsic functional
connectivity contrast (ICC). We used ICC power to
quantify changes in communications between neural
networks, upon administration of Propofol, and test the
hypothesis of process-coherence theories. Our results
demonstrate the enhancement of synchronous oscillations
in the DMN in the presence of Propofol, and such
increases in synchronous oscillations may be a
prerequisite for producing sleepiness and
unconsciousness.
|
2870. |
75 |
Mapping of cortico-cortical
and cortico-subcortical alterations in functional
connectivity induced by light sedation with propofol. ![](play.gif)
Tommaso Gili1, Neeraj Saxena2, Ana
Diukova1, Kevin Murphy1, Judith E
Hall2, and Richard G Wise1
1Cardiff University Brain Research Imaging
Centre (CUBRIC), Cardiff, United Kingdom, 2Section
of Anaesthetics, Intensive Care and Pain Medicine,
Cardiff University School of Medicine, Cardiff, United
Kingdom
We have examined alterations in functional connectivity
induced by propofol sedation in a group of healthy
volunteers. Large cortical areas (occipital, temporal,
frontal and parietal) were used as seed regions for the
functional connectivity analysis. While there appeared
to be little involvement of the default-mode network in
sedation related changes, thalamo-cortical functional
connectivity was modified. This is consistent with
previous suggestions of altered thalamo-cortical
communication in sedation and pharmacologically induced
loss of consciousness.
|
2871. |
76 |
Can time under anesthesia
affect resting state connectivity? ![](play.gif)
Benito de Celis Alonso1, Silke Kreitz2,
Silvia Hidalgo Tobón3, Carlos Herrera1,
Florian Spiegel2, Sebastian Spiegel2,
Marina Sergeyeva2, and Andreas Hess2
1Faculty of Medicine, BUAP, Benemérita
Universidad Autónoma de Puebla, Puebla, PUE, Mexico, 2Pharmacology
and Toxicology, FAU Erlagen-Nuremberg, Erlangen, Bayern,
Germany, 3UAM
Universidad Autónoma de México, Mexico
Resting-state imaging analyzes the low frequency
fluctuations of the BOLD signal (0.01-0.1 Hz) when brain
is at rest. It is accepted that these fluctuations
reflect neuronal activity (1,2) and also a certain
degree of structural (3) and functional connectivity
(4). It is known that resting states are reproducible in
other order of mammalians (5) and that they are not
affected by sleep (6) or even sedation (7). Results for
rodents are obtained regularly under anesthesia and
apparently the narcotic has no effect on resting-states
(8,9) even if other authors establish that there should
be anesthetic confounds (10, 11). No study tackles the
effect on resting-states of total experimental time
under anesthesia. In this study, we compared resting
states in two scenarios, one before and after an fMRI
experiment and other when no fMRI experiment was
performed between resting state measurements. Our
results show that there is a decay in both cases of
correlation strength that depends on the total time
animals have been under anesthesia, This decay does not
seem to imply a change in the nature of the
correlations.
|
2872. |
77 |
Disruption of
interhemispheric functional connectivity by peripheral nerve
block ![](play.gif)
Todd B Harshbarger1, M. Stephen Melton2,
Allen W Song1, and Stephen Klein2
1Brain Imaging and Analysis Center, Duke
University, Durham, NC, United States, 2Anesthesiology,
Duke University Medical Center, Durham, NC, United
States
Functional connectivity is increasingly used to compare
normal brain states with various disorders. In this
study, we investigated resting state functional
connectivity before and after a peripheral nerve block.
We show that cross-hemispheric correlations in motor
areas which exist before the block is applied are
disrupted by the nerve block. These correlations return
immediately after the block wears off. This can have
implications in the study of connectivity and
correlations between hemispheres, as well as potential
implications for studies of how the brain reacts to
damage in the peripheral nervous system.
|
2873. |
78 |
Impaired Functional
Connectivity between the Hippocampus and Dorsolateral
Prefrontal Cortex in a Neonatal Hippocampal Lesion Macaque
Model
Chunxia Li1, Zhihao Li2, Xiaoping
Hu2, Jocelyne Bachevalier3, and
Xiaodong Zhang1,4
1Yerkes Imaging Center, Yerkes National
Primate Research Center, Emory University, Atlanta,
Georgia, United States, 2Department
of Biomedical Engineering, Georgia Institute of
Technology and Emory University, Atlanta, Georgia,
United States, 3Yerkes
National Primate Research Center and Department of
Psychology, Emory University, Atlanta, Georgia, United
States, 4Division
of Neuropharmacology and Neurologic Disease, Yerkes
National Primate Research Center, Emory University,
Atlanta, Georgia, United States
Macaques with neonatal hippocampal lesions showed
hippocampal-dependent and prefrontal-dependent memory
deficits similar to those reported in schizophrenic
patients and are thus an ideal animal model to study the
mechanism of the abnormal functional connectivity
reported in schizophrenia. In this study, rhesus monkeys
with neonatal hippocampal lesions were used to
investigate the functional connectivity between the
hippocampus (HP) and the dorsolateral prefrontal cortex
(DLPFC) with the resting-state functional MRI technique.
The results showed weaker functional connectivity
between left HP and left DLPFC in animals with neonatal
HP lesions, and the degree of abnormal connectivity was
significantly correlated with volume of HP lesion.
|
2874.
![](MAGNA25.jpg) |
79 |
Resting-state Functional
Connectivity Altered by Complete and Partial Corpus
Callosotomy in Rats ![](play.gif)
Iris Y. Zhou1,2, Y. X. Liang3, Joe
S. Cheng1,2, Russell W. Chan1,2,
Kevin C. Chan1,4, K. F. So3, and
Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal
Processing, The University of Hong Kong, Hong Kong SAR,
China, 2Department
of Electrical and Electronic Engineering, The University
of Hong Kong, Hong Kong SAR, China, 3Department
of Anatomy, The University of Hong Kong, Hong Kong SAR,
China, 4Center
for the Neural Basis of Cognition, University of
Pittsburgh and Carnegie Mellon University, Pittsburgh,
PA, United States
Resting-state fMRI has been increasingly used in the
diagnosis of a variety of brain diseases. However, the
underlying mechanism of the spontaneous fluctuations in
rsfMRI signals is still under debate. In this study, the
effects of complete and partial transection of corpus
callosum (CC) on rsfMRI signal were investigated. The
loss of interhemispheric functional connections after
the complete transection of CC was observed. More
importantly, partial CC transection disrupted only the
specific intercortical functional connection that is
known to be anatomically connected through CC. These
findings further indicate that the spontaneous
fluctuations in rsfMRI signal largely reflect the
anatomical connections.
|
2875. |
80 |
Changes in Resting
Connectivity between Functional Networks in a Patient with
Significant Recovery from Complete Cervical Spinal Cord
Injury ![](play.gif)
Ann S Choe1,2, Visar Belegu1,2,
Cristina Sadowsky2,3, Peter C van Zijl4,5,
James Pekar4,5, and John McDonald1,2
1Department of Neurology, Johns Hopkins
University School of Medicine, Baltimore, MD, United
States, 2International
Center for Spinal Cord Injury, Hugo Moser Research
Institute at Kennedy Krieger Inc, Baltimore, MD, United
States, 3Physical
Medicine and Rehabilitation, Johns Hopkins University
School of Medicine, Baltimore, MD, United States, 4Russell
H. Morgan Department of Radiology and Radiological
Science, Johns Hopkins University School of Medicine,
Baltimore, MD, United States, 5F.M.
Kirby Research Center for Functional Brain Imaging,
Kennedy Krieger Institute, Baltimore, MD, United States
Can MRI inform classification of spinal cord injury
(SCI), and assess consequent brain changes? In this
study, we used advanced MR methods to report on the
structural and functional alterations in the central
nervous system of a patient who recovered significant
neurological function after SCI. Pattern of changes in
diffusion tensor imaging and magnetization transfer
imaing-derived parameters in the cord was consistent
with the subject¡¯s motor and sensory function
evaluations, and the changes in the BNC of the subject
was consistent with the subject¡¯s clinical
presentation, suggesting that rs-fMRI can be used to
observe brain functional changes of SCI subjects.
|
2876. |
81 |
Structural and functional
connectivity in amyotrophic lateral sclerosis
![](play.gif)
Molly Claire Chapman1, Laura Marie
Jelsone-Swain2, and Robert Cary Welsh2
1School of Medicine, University of Michigan,
Ann Arbor, MI, United States, 2Radiology,
University of Michigan, Ann Arbor, MI, United States
We examine diffusion tensor metrics and resting state
functional connectivity in an amyotrophic lateral
sclerosis population.
|
2877. |
82 |
Abnormality of variance of
resting state fMRI signal in white matter for schizophrenia ![](play.gif)
Hu Cheng1, Jerillyn Kent1, Mallory
Klaunig1, Dae-Jin Kim1, Brian
O'donnell1, William Hetrick1, and
Aina Puce1
1Indiana University, Bloomington, IN, United
States
Recently, abnormalities in the amplitude of low
frequency resting state fMRI signal have been observed
in schizophrenia patients. In this report, we examined
the variance of the signal in resting state fMRI across
the whole brain, and found significant differences
between schizophrenia patients and non-patient controls.
The controls showed higher temporal SNR mainly in the
white matter, clustered in several regions including
temporal, frontal, and parietal lobes, cerebellum,
anterior cingulate, and major white matter tracts. White
matter abnormalities in these regions have been
previously reported in schizophrenia patients.
|
2878. |
83 |
Complexity and
synchronicity of resting state fMRI in normal aging and
familial Alzheimer's disease ![](play.gif)
Collin Liu1,2, Anitha Priya Krishnan3,
Lirong Yan1, Jeffrey R Alger1,
John Ringman4, and Danny JJ Wang1,4
1Ahmanson-Lovelace Brain Mapping Center,
UCLA, Los Angeles, CA, United States, 2Neurobehavior
Unit, VA Greater LA Healthcare System, Los Angeles, CA,
United States, 3Molecular
Imaging Center, USC, Los Angeles, CA, 4Neurology,
UCLA, Los Angeles, CA
Interpretation of biological signals is essential for
diagnosing diseases. Pattern recognition and spectral
analyses have commonly been used. More recently a
non-linear time-series analysis called approximate
entropy has been applied to EEG, ECG, and hormonal
levels. Here we applied approximate entropy to resting
state BOLD fMRI time-series, to characterize the
complexity of the signal in normal aging and familial
Alzheimer's disease. Similar calculation can be made
between the time-series of a seed voxel and that of all
other voxels to provide a measure of synchronicity. This
is called cross-approximate entropy. These analyses
might provide novel measures of functional connectivity,
complementary to cross-correlation.
|
2879. |
84 |
The power spectral density
of slow fluctuation BOLD signal analysis during
resting-state functional magnetic resonance image in
fibromyalgia
Jeehye Seo1, Hui-jin Song1,
Seong-Uk Jin1, Hee-Kyung Kim1,
Jang Woo Park1, Moon Han1, Jong Su
Baeck1, Ji-Young Kim2, and Yongmin
Chang1,3
1Medical & Biological Engineering, Kyungpook
National University, Daegu, Jung-gu, Korea, 2School
of Medicine, Kyungpook National University, Daegu, Jung-gu,
Korea, 3Molecular
Medicine, Kyungpook National University, Daegu, Jung-gu,
Korea
Fibromyalgia (FM) is a medical disorder characterized by
chronic widespread pain, a heightened and painful
response to pressure. Currently, no investigation is
available for identifying the power spectral density of
low frequency BOLD fluctuations during resting-state
functional magnetic resonance imaging (rs-fMRI) while
recent study evaluated functional connectivity of low
frequency fluctuation in FM patients. Using seed-based
analysis of low frequency BOLD fluctuations in pain
related networks, our results demonstrated (1) the
medial and lateral pain networks of slow fluctuation
BOLD signal during rs-fMRI and (2) the differences in
the power spectral density within pain-related networks
between FM patients and healthy controls.
|
2880. |
85 |
Spatiotemporal Correlation
of Optical Neuronal Calcium Recordings with BOLD fMRI in
Rats ![](play.gif)
Albrecht Stroh1, Florian Schmid2,
Lydia Wachsmuth2, Valentin Riedl1,
Afra Wohlschlaeger3, Jenny Kressel3,
Claus Zimmer3, and Cornelius Faber2
1Technical University Munich, Munich,
Germany, 2University
Hospital Muenster, Germany, 3Technical
University Munich, Germany
Furthering our understanding of the spatiotemporal
dynamics of neurovascular coupling requires the
simultaneous and unperturbed recording of neuronal
spiking and BOLD fMRI. Here, we demonstrate the
feasibility of optical recording of neuronal activity
with sub-millisecond temporal precision within a 9.4 T
small animal scanner and simultaneously recording BOLD
fMRI. Using fluorescent indicators for intracellular
Ca2+ concentrations, we achieve a direct optical readout
of super-threshold neuronal spiking activity, enabling
the temporal and spatial correlation of BOLD time course
and neuronal firing patterns.
|
2881. |
86 |
The Influence of Laser
Power and Pulse Characteristics on the Optogenetically
Induced BOLD Signal of Excitatory Neurons in the Mouse
Hippocampus at 9.4T ![](play.gif)
Philipp Lebhardt1, Wolfgang Kelsch2,3,
Claudia Falfan-Melgoza1, Gabriele Ende1,
Alexander Sartorius2, and Wolfgang Weber-Fahr1
1NeuroImaging, Central Institute of Mental
Health, Mannheim, Germany, 2Clinic
of Psychiatry and Psychotherapy, Central Institute of
Mental Health, Mannheim, Germany, 3Cinical
Neurobiology, University of Heidelberg, Hiedelberg,
Germany
In this study we were interested in the influence of
laser power and stimulation frequency on the
optogenetically induced BOLD signal of the hippocampal
network in mice. We induced expression of
channelrhodopsin-2 in Ca2+/calmodulin-dependent protein
kinase II-expressing neurons by virus injection. Laser
stimulation was periodically applied through an optical
fiber in the left hippocampus with block and event
related designs using different power and stimulation
characteristics. We found activation and deactivation
due to laser heating effects even at low power levels
and diverse activation patterns in dependency of
stimulation length and frequency
|
2882. |
87 |
Optogenetic control of the
BOLD response during local suppression of neuronal activity
by muscimol
Daniil Aksenov1,2, Limin Li1,2,
Michael Miller1,2, George Iordanescu1,2,
and Alice Wyrwicz1,2
1NorthShore Univ. RI, Center for Basic MR
Research, Evanston, IL, United States, 2Pritzker
Sch. of Med., Univ. of Chicago, Chicago, IL, United
States
Optogenetic control offers great potential for studying
the relationship between BOLD and neuronal activity in
specific cell populations under a variety of modulatory
conditions. In this work, we combine simultaneous fMRI
and electrophysiological recording in the whisker barrel
cortex with localized pharmacological modulation and
optogenetic stimulation to examine the BOLD response in
awake rabbits before and after local injection of the
GABA-A agonist muscimol. Our results indicate that BOLD
area and magnitude are preserved during optical
stimulation in the cortex even in the presence of
increased inhibition produced by muscimol injection, but
thalamic BOLD response decreased after injection.
|
2883. |
88 |
Arterial cerebral blood
volume (CBVa) weighted functional MRI using pseudocontinuous
arterial spin labeling
Hesamoddin Jahanian1,2, Scott Peltier1,2,
Douglas C Noll1,2, and Luis Hernandez-Garcia1,2
1Functional MRI Laboratory, University of
Michigan, Ann Arbor, Michigan, United States, 2Department
of Biomedical Engineering, University of Michigan, Ann
Arbor, Michigan, United States
Functional magnetic resonance imaging using
physiological parameters such as cerebral blood
perfusion or cerebral blood volume (CBV), unlike BOLD
fMRI, provides a quantifiable contrast and is also more
closely related to neural activity. Current
Perfusion-based fMRI techniques, however, suffer from
poor sensitivity and low temporal resolution. It has
recently been shown that the change in CBV during neural
activation mainly originates from arterial rather than
venous blood volume, but CBV-based fMRI methods (such as
VASO and MOTIVE) are also limited by their low signal to
noise ratio. We propose a novel method based on
pseudocontinuous arterial spin labeling (pCASL)
technique to achieve a contrast that depends on arterial
cerebral blood volume (CBVa) and can be used for
functional imaging experiments. The method proposed here
offers sensitivity to brain activation that is on par
with BOLD imaging and superior to perfusion ASL, while
maintaining most of the advantages of perfusion ASL
imaging.
|
2884. |
89 |
Functional Blood Volume
Imaging (fBVI) using Blood Pool Gadolinium Contrast Agent
Gadofosveset Trisodium
Deqiang Qiu1, David E Rex1,
Manojkumar Saranathan1, Robert M Lober2,
Greg Zaharchuk1, Michael E Moseley1,
and Kristen W Yeom1
1Radiology, Stanford University, Stanford,
CA, United States, 2Neurosurgery
and Division of Child Neurology, Stanford University,
Stanford, CA, United States
Functional MRI (fMRI) has commonly been performed using
a T2*-based BOLD (Blood oxygenation level dependent)
technique, which depends on complex interactions between
multiple physiological processes and has inherent
resolution limits due to sensitivity to large veins. In
this paper, we present the first human demonstration of
the use of blood pool agent gadofosveset trisodium (Ablavar)
for functional T1-based blood volume MRI. Development of
T1 contrast agent based fMRI will lead to
high-resolution and distortion-free brain mapping
techniques.
|
2885. |
90 |
Evaluation of a functional
MRI Assay Using a Novel USPIO Contrast Agent (Ferumoxytol)
in Normal Healthy Volunteers ![](play.gif)
Richard Baumgartner 1, William Cho 2,
Alexandre Coimbra 2, Cynthia Gargano 3,
Robert Iannone 4, Arie Struyk 4,
Rebecca Fox 4, Zaiqi Wang 4, Fuqiang
Zhao 5, Donald Williams 5, Torsten
Reese 6, Brian Henry 7, Esben
Petersen 8, Chris Chen 9, Dai Feng 3,
Sofia Apreleva 3, and Jeffrey Evelhoch 5
1Biostatistics and Research Decision Sciences
(BARDS), Merck Research Laboratories (MRL), Rahway, New
Jersey, United States, 2Genentech, 3BARDS,
MRL, 4Experimental
Medicine, MRL, 5Imaging,
MRL, 6Center
for Cooperative Research in Biomaterials, Spain, 7Translational
Medicine Research Center, MRL,8Clinical
Imaging Center, Singapore, 9Singapore
National University
|
2886.
![](MAGNA25.jpg) |
91 |
An fMRI Phantom Based on
the Alignment of Molecular Dipoles with an Electric Field ![](play.gif)
Yujie Qiu1, Edmund Kwok2, and
Joseph P Hornak1
1Imaging Science, Rochester Institute of
Technology, Rochester, NY, United States, 2Imaging
Science, University of Rochester Medical Center,
Rochester, NY, United States
A new concept for an fMRI phantom is presented where the
T2 of
a non-viscous, high dielectric constant liquid is
changed by the application of an electric field. The
electric field aligns the dipoles in the liquid, thus
changing the molecular motions and T2. The T2 value
of propylene carbonate was changed from 45 to 36 ms by
the application of a 116 V/cm electric field. This T2 change
will produce a 15% change in the signal, comparable to
the 5-20% seen for the BOLD response. This concept may
allow changing the T2 at
rates comparable to the BOLD response.
|
2887. |
92 |
MRI detection of
short-duration "epileptiform" discharges in an ionic-current
phantom ![](play.gif)
Mukund Balasubramanian1, Padma Sundaram1,
William W. Wells2, Tobias Loddenkemper3,
Robert V. Mulkern1, and Darren B. Orbach1
1Department of Radiology, Children's Hospital
Boston, Boston, Massachusetts, United States, 2Department
of Radiology, Brigham and Women's Hospital,3Department
of Neurology, Children's Hospital Boston, Boston,
Massachusetts, United States
In order to determine the limits of detecting
short-duration currents with the phase of gradient-echo
EPI, we imaged a phantom carrying ionic currents of
various amplitudes and duty cycles, including those
approximating epileptiform activity. Our results
demonstrate the feasibility of detecting DC pulses with
durations of 200 milliseconds or longer, for current
amplitudes that are plausible for interictal discharges.
Although our particular focus is on epilepsy, the
ability to reliably image neuronal currents in general
would provide a novel and important contrast mechanism
for fMRI, with widespread applicability.
|
2888. |
93 |
Combined Vessel Size and
Blood Flow Imaging with Hyperoxia ![](play.gif)
Michael Germuska1, Thies Jochimsen2,
Michael Kelly1, Tom Okell1, and
Daniel Bulte1
1Nuffield Dept. of Clinical Neurosciences,
University of Oxford, Oxford, Oxon, United Kingdom, 2PET-MR
Group, Department of Nuclear Medicine, University of
Leipzig, Leipzig, Germany
Of particular interest when assessing neuro-angiogenesis
are changes in blood flow, blood volume and vessel size.
Here we present an MR imaging protocol that maybe used
to make simultaneous measurements of these parameters in
humans. The protocol uses a modified pseudo-continuous
ASL sequence, with a dual gradient-spin echo EPI
readout. Periods of mild hyperoxia are used to modulate
the BOLD signal during acquisition. Mean vessel size
maps and blood volume are calculated from the change in
spin echo and gradient echo images. While the gradient
echo signal is used to calculate resting blood flow.
|
2889. |
94 |
Comparisons of
diffusion-weighted and BOLD fMRI signals in the rat
somatosensory cortex. ![](play.gif)
Tomokazu Tsurugizawa1, Luisa Ciobanu1,
and Denis Le Bihan1
1Neurospin, Gif sur Yvette, France
Diffusion-weighted functional MRI (DfMRI) has been shown
to be sensitive to neural activation in the human brain.
In this study, I compared the DfMRI (b=10, 250, and
1800) and BOLD signal changes in rat somatosensory
cortex under hyperoxia without neuronal stimulation and
forepaw electrical stimulation. The amplitude of the
high b-value DfMRI (b=1800) signal was lower than those
of BOLD signal during hyperoxia. During the forepaw
stimulation, early return-to-baseline of the high
b-value DfMRI response was observed compared to BOLD
response. These results show that the BOLD and DfMRI
signal point out different mechanisms.
|
2890. |
95 |
Activation by fasting
changes diffusion parameters of the hypothalamus in the
adult human brain as detected by DWI
![](play.gif)
Blanca Lizarbe1, Maria Lusia Garcia-Martin2,3,
Pilar Lopez-Larrubia1, and Sebastian Cerdan1
1Instituto Investigaciones Biomedicas
"Alberto Sols", Madrid, Spain, 2Magnetic
Ressonance Unit, Clinica Nuestra Senora del Rosario,
Madrid, Spain, 3Head
Nano-Imaging Facility, Parque Tecnológico de Andalucía,
Malaga, Spain
We report on the use of functional DWI as a robust
marker of hypothalamic activation by fasting in human
subjects. Six adult male where imaged (DWI, three
directions) in two different situations, fed (after one
week of a balanced diet), and after 24 hours of fasting.
Two areas of the brain, the hypothalamus and the cortex,
were investigated using a biexponential model of
diffusion. Fasting is shown to elicit significant, and
directionally-dependent, changes of the biexponential
diffusion parameters in the hypothalamus, suggesting an
activation-induced cell swelling. These results open the
possibility to examine feeding disorders and their
therapies by DWI.
|
2891. |
96 |
Validation of
Diffusion-Weighted FMRI signal in vitro using brain slices ![](play.gif)
Nyoman D. Kurniawan1, John Power2,
Natalie Alexopoulos1, Donald J Maillet3,
Michael Vogel1, Ian M. Brereton1,
and David C. Reutens1
1Centre for Advanced Imaging, University of
Queensland, Brisbane, Queensland, Australia, 2Queensland
Brain Institute, University of Queensland, Brisbane,
Queensland, Australia, 3Centre
for Advanced Imaging, University of Queensland,
Brisbane, Australia
Diffusion-weighted FMRI (DFMRI) was suggested to provide
a more direct measurement of neuronal activation (Le
Bihan et al., 2006). DFMRI methods are thought to
reflect cell swelling and a reduction in extracellular
space accompanying the influx of water and ions in
active neurons. However, there is some evidence that in
vivo DFMRI signals may be contaminated by haemodynamic/BOLD
effects and thus put doubts about the significance and
origin of the DFMRI signal. In this study, we aimed to
verify the origin of DFMRI signal in vitro using
perfused brain slices free from haemodynamic effects. We
found that DFMRI could detect activation signal in the
absence of hemodynamic effects. In hippocampal slices,
K+ stimulation induced changes in DFMRI signal with a
similar spatial distribution and time course to that
observed with fluorescence microscopy.
|
|
|
Electronic
Poster Session - fMRI |
|
fMRI: Neuroscience Applications & Brain Physiology
Click on
to view
the abstract pdf and click on
to view the
video presentation. (Not all presentations are available.)
Monday 7 May 2012
Exhibition Hall |
11:45 - 12:45 |
|
|
|
Computer # |
|
2892. |
73 |
Activation in thalamus
predicts state and trait anxiety: An fMRI perspective of
attentional control theory
![](play.gif)
Shilpi Modi1, Manas K Mandal2,
Prabhjot Kaur1, Rajendra P Tripathi1,
and Subash Khushu1
1Institute of Nuclear Medicine and Allied
Sciences (INMAS), Delhi, Delhi, India, 2Defence
Institute of Psychological Research, Delhi, Delhi, India
Anxiety impairs the inhibition function and hence,
increased distractibility is found in anxious
individuals compared with nonanxious ones. fMRI was
carried out to map neural correlates for an attention
task that required distracter inhibition. Individual
differences in state and trait anxiety levels were
regressed with individual BOLD activation patterns.
Multiple regression analysis results indicate that the
activation in thalamus predicted lower state anxiety and
higher trait anxiety levels of subjects Results further
suggest that different types of anxiety—state or
trait—may influence attention differently.
|
2893. |
74 |
The effect of fat on the
cortical response to flavour ![](play.gif)
Sally Eldeghaidy1,2, Luca Marciani1,3,
Tracey Hollowood4, Kay Head1,
Johanneke Busch5, Andrew J. Taylor4,
Tim Foster6, Robin C. Spiller3,
Joanne Hort4, Penny A. Gowland1,
and Susan Francis1
1Sir Peter Mansfield Magnetic Resonance
Centre, School of Physics and Astronomy, University of
Nottingham, Nottingham, Nottinghamshire, United Kingdom, 2Department
of Physics, Suez Canal University, Ismailia, Egypt, 3Nottingham
Digestive Diseases Centre NIHR Biomedical Research Unit,
Nottingham University Hospitals, Nottinghamshire, United
Kingdom, 4Sensory
Science Centre, Division of Food Sciences, University of
Nottingham, Loughborough, Leicestershire, United
Kingdom, 5Unilever
R&D, Vlaardingen, Netherlands, 6Division
of Food Sciences, University of Nottingham, Loughborough,
Leicestershire, United Kingdom
The increase understanding of the impact of fat on the
flavour perception could assist the design of food
products that are lower in fat but still rewarding to
eat. Here, we mapped the cortical representation to no
flavoured fat, flavoured no fat, iso-release and
perceived flavoured fat emulsions. We show that the
presence of fat in the oral cavity reduces the cortical
response to flavour, particularly in the primary taste
areas and anterior cingulate, even when samples are
iso-perceived (or volatile release) for sweetness,
flavour and thickness.
|
2894. |
75 |
Functional MRI of
Auditory-Visual Convergence in the Superior Colliculus ![](play.gif)
Kyle K. Xing1,2, Condon Lau1,2,
Patrick P. Gao1,2, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal
Processing, the University of Hong Kong, Hong Kong,
China, 2Department
of Electrical and Electronic Engineering, the University
of Hong Kong, Hong Kong, China
Extensive research has been conducted to understand how
the central nervous system receives information from
individual sensory channels and converts it into
perceptions of sight, sound, touch, smell, and taste.
Neurons in the superior colliculus (SC) respond to
auditory and visual inputs, but noninvasive fMRI studies
have only observed visual responses. In this study, we
apply BOLD fMRI on rats to measure the hemodynamic
responses in the SC and inferior colliculus following
auditory and visual stimulation. Responses are observed
in the SC during both stimuli, providing the first fMRI
evidence of auditory-visual convergence in the SC.
|
2895. |
76 |
Group Differences in Brain
Activity between Dyslexic Children and Normal Controls Using
Functional Magnetic Resonance Imaging
Youngseob Seo1,2, Zhiyue J Wang1,2,
Srinivas Rachakonda3, Jonathan M Chia4,
and Nancy K Rollins1,2
1Radiology, The University of Texas
Southwestern Medical Center at Dallas, Dallas, Texas,
United States, 2Radiology,
Children's Medical Center Dallas, Dallas, Texas, United
States, 3University
of New Mexico, 4Philips
Healthcare
Dyslexia is referred to as specific reading
disability/retardation in spite of conventional
instruction and adequate intelligence. Learning to read
is one of the most important skills for children to
acquire in early education. We compared brain activities
between dyslexic children and normal controls for
reading and action-related tasks using fMRI and group
ICA. We demonstrated there are differences in brain
function activities in visual, executive, auditory,
motor, sensory cortexes and Broca’s area between the 2
groups.
|
2896. |
77 |
Imaging brain response to
exercise fatigue and exhaustion: an ASL perfusion study
![](play.gif)
Ying Hao1, Zhiyue Xia2, Haibin Zhu3,
Xiaoying Wang1,3, Jing Fang1,4,
Jue Zhang1,4, and Dapeng Bao2
1Academy for Advanced Interdisciplinary
Studies, Peking University, Beijing, Beijing, China, 2Beijing
Sport University, 3Peking
University First Hospital,4Department of
Engineering, Peking University
Most studies have utilized noninvasive BOLD-fMRI to
depict the central neural adaption to physical fatigue
or exhaustion; however, the large-scale effects of
exercise on the cardio-pulmonary systems may influence
the blood oxygen level dependent (BOLD) signal
independent of neuronal activation. Thus, arterial spin
labeling (ASL), which is capable of acquiring regional
CBF values noninvasively, was proposed here to depict
the brain response to exercise fatigue and exhaustion.
Eight athletes were conducted the PASL scan pre- and
post- the ergometer tasks on fatigue and exhaustion
levels. Significant CBF reduction was observed after
both kinds of exercises.
|
2897. |
78 |
The Basal Ganglia Coupling
during Social Interaction Revealed by Dyadic fMRI ![](play.gif)
Ray Lee1
1Neuroscience Institute, Princeton
University, Princeton, NJ, United States
Taking advantage of emerging dyadic fMRI (dfMRI), a
study on two human-brain interactions inside one MRI
scanner was conducted. Besides confirmed most of the
previous results regarding BOLD effect in social
cognition, the probabilistic independent component
analysis (PICA) results of our dfMRI data reveal that
the basal ganglia coupling between two brains could be
an essential stage in social cognition. This is the
first time that fMRI shows that a special region of
brain during social interaction becomes correlated,
while most other BOLD effects due to social interaction
are only coherent within each individual brain.
|
2898. |
79 |
fMRI Study of Sound
Pressure Level Processing in the Central Auditory System ![](play.gif)
Jevin W. Zhang1,2, Condon Lau1,2,
Joe S. Cheng1,2, Kyle K. Xing1,2,
Iris Y. Zhou1,2, Matthew M. Cheung1,2,
and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal
Processing, The University of Hong Kong, Hong Kong SAR,
China, 2Department
of Electrical and Electronic Engineering, The University
of Hong Kong, Hong Kong SAR, China
Intensity is an important physical property of the sound
wave and is usually reported as sound pressure level
(SPL). This study examines the fMRI hemodynamic
responses in the rat inferior colliculus (IC), lateral
lemniscus (LL), medial geniculate body (MGB) and
auditory cortex (AC) over a broad 72dB SPL range using
sparse temporal sampling. The BOLD signal change
increases significantly with SPL in IC and LL, but not
in MGB and AC, which agrees with electrophysiology
findings. This is the first fMRI observation of
differences in SPL dependences between auditory
structures and furthers our understanding of SPL
processing.
|
2899. |
80 |
Functional MRI of the
Olfactory System in Awake and Anesthetized Dogs ![](play.gif)
Hao Jia1, Oleg Mykolajovych Pustovyy2,
Paul Waggoner3, Ronald J Beyers1,
John Schumacher4, Jay Barrett5,
Edward Morrison2, Robert L Gillette4,
Thomas S Denney1,6, Vitaly J Vodyanoy5,
and Gopikrishna Deshpande1,6
1AU MRI research center, Dept. of ECE, Auburn
University, Auburn, Alabama, United States, 2Dept.
of Anatomy, Physiology & Pharmacology, Auburn
University, Auburn, Alabama, United States, 3Canine
Detection Research Institute, Auburn University, Auburn,
Alabama, United States, 4Dept.
of Clinical Sciences, Auburn University, Auburn,
Alabama, United States, 5College
of Veterinary Medicine, Auburn University, Auburn,
Alabama, United States, 6Dept.
of Psychology, Auburn University, Auburn, Alabama,
United States
Canines are used extensively for detecting odors in both
civilian and national security contexts, but their
olfactory system remains largely unexplored in vivo. We
developed and demonstrated the feasibility of an
experimental setup for controlled delivery of odorant
stimulus to both conscious and lightly anesthetized
dogs. We found that in awake dogs, regions modulated by
odor concentration were mainly in the frontal cortex,
while that in anesthetized dogs were primarily in lower
structures such as brain stem. The differential response
to concentrations in awake and anesthetized dogs provide
in vivo demonstration of previous ex vivo cellular
recordings.
|
2900. |
81 |
Heritability of
hemodynamic response function of human brain during working
memory task ![](play.gif)
Zuyao Y Shan1, Katie L McMahon1,
Greig I de Zubicaray2, Paul M Thompson3,
Nicholas G Martin4, Margaret J Wright4,
and David C Reutens1
1Centre for Advanced Imaging, The University
of Queensland, Brisbane, QLD 4072, Australia, 2School
of Psychology, The University of Queensland, Brisbane,
QLD 4072, 3Laboratory
of Neuro Imaging, Department of Neurology, UCLA School
of Medicine, Los Angeles, CA, United States, 4Genetic
Epidemiology Laboratory, Queensland Insitute of Medical
Research, Brisbane, QLD 4029, Australia
Neurovascular coupling is crucial for normal brain
function but the contribution of genetic factors to
coupling mechanisms is poorly understood. We
investigated the heritability of the hemodynamic
response function (HRF) of BOLD fMRI in the brain using
the twin methodology, in which the degree of concordance
between monozygotic (MZ, identical) and dizygotic (DZ,
fraternal) twin pairs is compared. We found smaller
differences in HRF time to peak in MZ than DZ twin
pairs. It suggests that this trait is heritable, perhaps
reflecting the genetic influence on neurovascular
coupling factors that control the timing of blood entry
into the activated area.
|
2901. |
82 |
SVM analysis of nicotine
craving using functional MRI ![](play.gif)
Yash Shailesh Shah1, Luis Hernandez-Garcia1,
Douglas C Noll1, Kinh Luan Phan1,
Mark K Greenwald2, Jon Kar Zubieta1,
and Scott J Peltier1
1University of Michigan, Ann arbor, Michigan,
United States, 2Wayne
State University, Detroit, Michigan, United States
Support vector machine learning from fMRI images for
application in real-time neurofeedback to regulate
craving in nicotine-dependent subjects.
|
2902. |
83 |
Assessment of Cerebral
Autoregulation by Inducing Acute Hypertension in Rats ![](play.gif)
Guang Li1,2, Yen-Yu I. Shih2,
Bryan H. De La Garza2, Jeffrey W. Kiel3,4,
and Timothy Q. Duong1,2
1Radiology, University of Texas Health
Science Center at San Antonio, San Antonio, TX, United
States, 2Research
Imaging Institute, University of Texas Health Science
Center at San Antonio, San Antonio, TX, United States, 3Ophthalmology,
University of Texas Health Science Center at San
Antonio, San Antonio, TX, United States, 4Physiology,
University of Texas Health Science Center at San
Antonio, San Antonio, TX, United States
There are clinical interests in dynamic cerebral
autoregulation (DCA) assessment in diseases such as
stroke and diabetic. We developed a rat model to assess
DCA through transient BF changes during acute
hypertension using MRI. We detected normal and impaired
CA, and also revealed BF and oxygenation increases
associated with acute BP elevation. Our study suggested
that CA was established at a higher BF level during
acute hypertension under normocapnia but it was impaired
under hypercapnia. This method can be used for quick
region-specific CA evaluation in normal and diseased
physiology and can be extended to other organs such as
eye.
|
2903. |
84 |
Paradoxical increase in
amygdala responsiveness to unpleasant stimuli through
peripheral beta-blockade: a pharmacological fMRI study ![](play.gif)
Rebecca Susan Dewey1,2, Olga Pollatos3,
Akram A. Hosseini1, Susan T. Francis2,
and Dorothee P. Auer1
1Radiological and Imaging Sciences,
University of Nottingham, Nottingham, Nottinghamshire,
United Kingdom, 2Sir
Peter Mansfield Magnetic Resonance Centre, University of
Nottingham, Nottingham, Nottinghamshire, United Kingdom, 3Department
of Psychology, Potsdam University, Potsdam, Germany
Reduction of peripheral nervous system feedback is
hypothesised to be associated with reduced neural
response to emotional stimuli. Emotional stimuli
typically elicit responses in the limbic system,
including the amygdala, brainstem and salience network
(anterior insula and anterior cingulate). The
peripherally acting beta-blocker, nadolol, reduces
peripheral autonomous nervous responses. Simultaneous
acquisition of perfusion weighted ASL and BOLD fMRI give
novel insight into regional drug induced changes in BOLD
and perfusion. This study reports a pharmacologically
induced increase in amygdala response to unpleasant
emotional visual stimuli as measured using BOLD fMRI.
Speculative explanations for paradoxical amygdala
behaviour are given.
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2904. |
85 |
Evaluation of a new qBOLD
approach to map local blood oxygen saturation in non human
primates ![](play.gif)
Julien Bouvier1,2, Affif Zaccaria1,3,
Irène Troprès4, Laurent Selek3,5,
Pierre Bouzat3,5, David Chechin2,
François Berger3,5, Alexandre Krainik3,5,
and Emmanuel Barbier1,3
1INSERM, U836, Grenoble, Isère, France, 2Philips
Healthcare, Suresnes, Ile de France, France, 3Université
Joseph Fourier, Grenoble Institute of Neurosciences,
Grenoble, France, 43T
Facility, SFR Biomedical NMR and Neurosciences,
Grenoble, France, 5CHU,
Grenoble, France
Tissue oxygenation can be characterized by local oxygen
saturation (lSO2), which may be mapped by quantitative
Blood Oxygen Level Dependent (BOLD) approaches. An
approach that combines separate estimates of T2, T2*,
BVf, and B0 inhomogeneities has recently been proposed
and validated in rats and a preliminary study has been
realized in humans. The aim of this study is to evaluate
this approach in non human primates under two depth of
anesthesia.
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2905. |
86 |
Hemodynamics under
pharmacological challenge in rat brain: comparison of BOLD,
CBV and CBF using bicuculline ![](play.gif)
Zeenat Atcha1, Hui Chien Tay1,
Fatima Ali Nasrallah1, Huang Wei Wei1,
Brian Henry2, and Kai-Hsiang Chuang1
1Magnetic Resonance Imaging Group, Singapore
Bioimaging Consortium, A*STAR, Singapore, Singapore,
Singapore, 2Medicine
Research Centre, MSD, Singapore, Singapore
The aim of our study was to investigate the sensitivity
and distinct spatiotemporal responses of bicuculine-induced
brain activity using three pharmacological magnetic
resonance imaging (phMRI) methods:
blood-oxygen-level-dependent (BOLD) contrast, cerebral
blood volume (CBV) with intravascular contrast agent,
and cerebral blood flow (CBF) with arterial spin
labeling (ASL). Acute administration of bicuculline
produced region-specific hemodynamic responses in the
S1, hippocampal, caudate putamen and thalamus regions.
Furthermore, we demonstrate that temporal dynamics of
CBV and BOLD signals were long lasting, whereas CBF
responses were immediate. Information obtained from
these complementary imaging techniques provide better
insights to underpin neurovascular coupling upon a drug
challenge.
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2906. |
87 |
Brain Oxygen Saturation
assessment using T2 Prepared Diffusion Imaging ![](play.gif)
Esben Thade Petersen1, Jill De Vis1,
Thomas Alderliesten2, Petra M. Lemmers2,
Karina J Kersbergen2, Manon Benders2,
C. A. T. van den Berg3, and Jeroen Hendrikse1
1Department of Radiology, UMC, Utrecht,
Netherlands, 2Neonatology,
Wilhemina Children's Hospital, Utrecht, Netherlands, 3Department
of Radiotherapy, UMC, Utrecht, Netherlands
Bloods oxygen saturation is an important parameter for
the evaluation of patients such as stroke or asphyxiated
newborns. Here we present a method for measurement of
blood T2 in the tissue using a “T2-Prepared Blood IVIM
Imaging of Oxygen Saturation” (T2-BIOS) sequence from
where bloods oxygen saturation can be estimated. IVIM
effects in diffusion-weighted imaging are exploited to
separate the blood signal and by using previous
determined relationships of T2 versus Y, one can
generate an oxygen saturation map. In the neonates this
information is obtained from NIRS and similarity is
shown, although not significantly correlated in this
small population.
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2907. |
88 |
Empirical estimation of
the Grubb exponent using simultaneously acquired CBF and
static magnetisation changes ![](play.gif)
Kevin Murphy1, Ashley D Harris1,
and Richard G Wise1
1CUBRIC, School of Psychology, Cardiff
University, Cardiff, United Kingdom
The Grubb exponent, α, describes the non-linear
relationship between CBV and CBF changes and is usually
assumed to be 0.38. Increases in CBV are reflected in
the static magnetisation (M0) changes of the BOLD
signal. This study proposes a model to use
simultaneously acquired static magnetisation and CBF
measurements to determine α. A previous model by
Woolrich et al., neglected M0 effects caused by
extravascular spins after CBV increases. This new model
accounts for both blood and non-blood effects on M0 and
removes the need to assume a baseline CBV value when
estimating the Grubb exponent.
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2908. |
89 |
Measurement of absolute
CMRO2 in
the human brain with calibrated FMRI ![](play.gif)
Richard G Wise1, Ashley D Harris1,
and Kevin Murphy1
1CUBRIC, School of Psychology, Cardiff
University, Cardiff, United Kingdom
We present a method for measuring absolute cerebral
metabolic oxygen consumption (CMRO2). ASL and
BOLD FMRI were combined with hypercapnic and hyperoxic
respiratory challenges. Under an assumption of iso-metabolism,
the BOLD signal calibration parameter (M) established in
hypercapnia was used with the hyperoxic BOLD signal
changes to estimate the resting venous deoxyhaemoglobin
concentration and therefore oxygen extraction fraction
and CMRO2, on a regional basis. This was
performed at rest and with continuous visual
stimulation. The proposed method may offer a useful
marker of cerebral metabolism in health and disease
given its non-invasiveness compared to radiotracer
methods.
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2909. |
90 |
Quantitative measurement
of functional cerebral blood volume changes with multi-echo
fMRI at 7T
![](play.gif)
Swati Rane1, Manus Donahue1,2, and
John C Gore1,3
1Radiology and Radiological Sciences,
Vanderbilt University Institute of Imaging Science,
Vanderbilt University, Nashville, TN, United States, 2Psychiatry,
Vanderbilt University, Nashville, TN, United States, 3Biomedical
Engineering, Vanderbilt University, Nashville, TN,
United States
Multi-echo fMRI experiments were performed at 7T with
and without REST slabs. Signal changes upon functional
activation were measured at TE = 0 ms as a measure of
functional CBV change. Simulations were also conducted
to study multi-echo fMRI signal characteristics and its
dependence on functional CBV changes
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2910. |
91 |
A simple heuristic model
for the BOLD response (that works remarkably well) ![](play.gif)
Valerie E.M. Griffeth1, Nicholas P Blockley2,
and Richard B Buxton2
1Department of Bioengineering, University of
California, San Diego, La Jolla, CA, United States, 2Department
of Radiology, University of California, San Diego, La
Jolla, CA, United States
We used a detailed model of the BOLD effect to reexamine
the original assumptions of the Davis model for
calibrated BOLD, particularly the relationship between
the BOLD signal and the change in total deoxyhemoglobin
content. A simple heuristic model, as an alternative to
the Davis model, incorporates transparent dependency on
the underlying physiology, and works remarkably well for
CBF/CMRO2 coupling
ratios from 1.3-5. Additionally, it directly defines the
null line of the BOLD response while also providing a
means by which to directly compare CBF/CMRO2 coupling
ratios between two stimuli without calibrating to
measure the scaling parameter, M.
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2911. |
92 |
Dependence of Cerebral
Blood Flow and Oxygen Consumption on Hyperoxia-Induced
Changes in the Longitudinal Relaxation Time ![](play.gif)
David Thomas Pilkinton1, and Ravinder Reddy1
1Center for Magnetic Resonance and Optical
Imaging, Department of Radiology, University of
Pennsylvania, Philadelphia, PA, United States
This work aims to develop a biophysical model that
relates blood flow and oxygen consumption to the
observed T1 decrease in tissues during hyperoxia.
Showing opposite trends compared to hyperoxic effects on
R2 (BOLD), hyperoxic R1 enhancement increases as CBF
increases and metabolism decreases. Using hypercapnia to
induce an isometabolic increase in CBF, our model
captures effects on R1 due to this physiological
parameter during hyperoxia. Since a comprehensive
validation of this model requires measuring hyperoxia as
a function of metabolism, future work will focus on
altered metabolic states.
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2912. |
93 |
Hyperoxic Calibrated
Quantitative fMRI for the Measurement of Regional Cerebral
Metabolic Rate of Oxygen in a Hypermetabolic Swine Model ![](play.gif)
David T Pilkinton1, Victor K Babu1,
Wesley Baker1, Joel H Greenberg2,
and Ravinder Reddy1
1Center for Magnetic Resonance and Optical
Imaging, Department of Radiology, University of
Pennsylvania, Philadelphia, PA, United States, 2Department
of Neurology, University of Pennsylvania, Philadelphia,
PA, United States
The aim of this study is to quantify relative metabolic
changes using hyperoxic calibrated BOLD/ASL fMRI in a
hypermetabolic swine model. Metabolic changes using this
large animal model were previously studied by our group
using gas that is isotopically-enriched with 17O2. We
sought to cross-validate these measurements with
hyperoxic dHb dilution methods of relative metabolism
and to compare the results of hyperoxia and hypercapnia
calibration methods using this animal model.
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2913. |
94 |
Quantification of Cerebral
Arteriole Oxygenation in Human Brain by qBOLD Technique
![](play.gif)
Xiang He1, Chan-Hong Moon1, Serter
Gumus1, Ayaz Aghayev1, JinHong
Wang1, Dmitriy A Yablonskiy2, and
Kyongtae Ty Bae1
1Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, United States, 2Mallinckrodt
Institute of Radiology, Washington University in St
Louis, St Louis, Missouri, United States
The objective of this study is a non-invasive
quantification of arteriole oxygenation in human brain
in the baseline state and during functional activation.
We applied a recently proposed MR-based ASL-qBOLD
technique to investigate T2* decay profile of ASL water
signal originated from large feeding arteries and small
arteries/arterioles. Our data demonstrate a gradual
decrease of arteriole blood oxygenation approaching
capillaries. We found that in arterioles the mean blood
oxygen saturation was 86.9±3.4%. During visual
stimulation, no significant change of arteriole blood
oxygenation was detected, which is consistent with the
results reported in previous studies using invasive
methods in rodent models.
|
2914. |
95 |
Non-invasive
Quantification of Absolute Cerebral Blood Volume Applicable
to the Whole Human Brain ![](play.gif)
Pelin Aksit Ciris1, Maolin Qiu1,
and Robert Todd Constable1
1Yale University, New Haven, CT, United
States
CBV changes occur across diverse pathologies and during
functional challenges, however, measurements have been
invasive and difficult especially in humans. In this
study, whole brain absolute CBV (mL blood/100mL
parenchyma) was measured non-invasively in 13 human
volunteers during visual stimulation; by further
developing a method based on a biophysical model with
rotating multi-slice acquisitions maintaining steady
state. Such non-invasive quantification could foster
improved understanding of the relationship between
neuronal activity, hemodynamic changes and metabolism
underlying fMRI signal, provide a reference for
calibrated fMRI, and potentially find clinical utility
in evaluating vascular state, vascular damage, and/or
monitoring treatments.
|
2915. |
96 |
Acute and chronic effects
of glucose on brain metabolism: findings from healthy
subjects and diseased conditions ![](play.gif)
Feng Xu1, Peiying Liu1, Juan
Pascual2, Xuchen Zhang2, and
Hanzhang Lu1
1Advanced Imaging Research Center, University
of Texas Southwestern Medical Center, Dallas, TX, United
States, 2Department
of Neurology, University of Texas Southwestern Medical
Center, Dallas, TX, United States
The glucose is the primary source of energy for the
brain and its effect on brain metabolism is not well
understood. With a recently developed technique
quantifying cerebral metabolic rate of oxygen (CMRO2),
we studied the acute and chronic effect of glucose on
healthy controls and GLUT-1 deficiency (GLUT-1 DS)
patients who suffer the chronic hypoglycemia in the
brain. In healthy subjects, the acute increase of
glucose reduced CMRO2. The baseline CMRO2 of Glut-1DS
patients is lower than healthy controls, and was
elevated after the glucose ingestion.
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