Joint Annual
Meeting ISMRM-ESMRMB 2014
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10-16 May 2014
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Milan, Italy |
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ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Diffusion Biophysics & Microstructures
Wednesday 14 May 2014
Exhibition Hall |
13:30 - 14:30 |
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Computer # |
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4412. |
1 |
Probing the vitality of
yeast suspensions by Double Diffusion Weighted MRI ![](play.gif)
Lars Mueller1, Andreas Wetscherek1,
Jutta Janke1, Bram Stieltjes2, and
Frederik Bernd Laun1
1Medical Physics in Radiology, German Cancer
Research Center, Heidelberg, Germany, 2Quantitative
Imaging-based Disease Characterization, German Cancer
Research Center, Heidelberg, Germany
A double diffusion weighted sequence was implemented and
tested on yeast suspension phantoms with different yeast
concentrations. The sequence allowed us to determine the
apparent exchange rate, which is a measure for water
exchange rates across cell membranes, and the filter
efficiency. Higher yeast concentrations result in lower
exchange rates and higher filter efficiencies. Both
parameters are dependent on the age of the yeast
suspension and are shown to be good indicators of the
vitality of the yeast suspension.
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4413. |
2 |
Double-PFG Filtered
Diffusion Tensors ![](play.gif)
Ofer Pasternak1, Markus Nilsson2,
Yoram Cohen3, Evren Ozarslan1,
Hans Knutsson4, and Carl-Fredrik Westin1
1Harvard Medical School, Boston, MA, United
States, 2Lund
University, Lund, Sweden, 3Tel
Aviv University, Tel Aviv, Israel, 4Linköping
University, Linköping, Sweden
While most current double PFG methods concentrate on
parameterization of new types of anisotropies in gray
matter, we provide here a simple and intuitive filtered
tensor based framework to explore the utility of double
PFG for mapping white matter. The preliminary results
shown here suggest that using filtered tensors has the
potential to resolve complex fiber architecture in an
intuitive, signal driven way, which is different than
the typically complex model based HARDI methods.
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4414. |
3 |
Oscillating gradient
diffusion MRI reveals frequency-dependent contrasts in
cellular layers of the human cerebellum ![](play.gif)
Manisha Aggarwal1 and
Susumu Mori1
1Department of Radiology, Johns Hopkins
University School of Medicine, Baltimore, MD, United
States
We investigate the effect of gradient frequency on
diffusion MR contrasts derived using oscillating
diffusion-sensitizing gradients in the fixed human
cerebellum. Using diffusion MRI data acquired at 11.7 T
with pulsed gradient and modified trapezoid-cosine
oscillating gradient waveforms (at frequencies of 67,
100, 150, and 200 Hz), we report the generation of
unique layer-specific contrasts in the human cerebellum.
Quantitative maps derived from the rate of change in ADC
measurements with gradient frequency revealed distinct
anatomical contrasts highlighting specific cerebellar
layers, which were compared with histologically-stained
sections of the same tissue. The results demonstrate the
potential of oscillating-gradient diffusion MRI
acquisitions to generate anatomical contrasts that are
sensitive to the microstructure of cellular layers in
the human cerebellar gray matter.
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4415. |
4 |
Imaging microstructure:
Application of oscillating gradient diffusion sequences on a
3T clinical MRI scanner ![](play.gif)
Lebina Shrestha Kakkar1, David Atkinson2,
Rachel W Chan2, and Ivana Drobnjak1
1Center for Medical Image Computing,
University College London, London, United Kingdom, 2Center
for Medical Imaging, University College London, United
Kingdom
Estimation of brain micro-structure parameters can be
used to improve understanding of neuro-degeneration due
to ageing or dementia. Recent studies show these
estimations are possible using pulsed gradient spin echo
sequences but are more accurately estimated using
trapezoidal oscillating gradient spin echo (tOGSE)
sequences. Here, we implement tOGSEs on a 3T MRI scanner
and test its feasibility by imaging: (1)microcapillaries
(2)an asparagus stem and (3)the corpus callosum of two
healthy volunteers. Their fiber diameters were estimated
using only 5 measurements with the three-stage fitting
model procedure. Our results suggest good agreement with
the ground truth and histology for our phantoms.
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4416. |
5 |
Mapping mean axon diameters
using diffusion MRI with oscillating gradients ![](play.gif)
Junzhong Xu1, Hua Li1, Kevin D
Harkins1, Jingping Xie1, Mark D
Does1, and John C Gore1
1Institute of Imaging Science, Vanderbilt
University, Nashville, Tennessee, United States
Due to relatively long diffusion times used, small axons
are usually overestimated using PGSE-based models. In
the current study, the OGSE method was implemented in
fixed spinal cord measurements with much shorter
effective diffusion times to enhance detection
sensitivity to small axons. The results show that the
fitted mean axon diameters are in very good agreement
with histology.
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4417. |
6 |
Fast and robust measurement
of microstructural dimensions using temporal diffusion
spectroscopy ![](play.gif)
Hua Li1, John C. Gore1, and
Junzhong Xu1
1Institute of Imaging Science, Vanderbilt
University, Nashville, TN, United States
Current PGSE-based approaches usually require long
scanning times and high q-values to detect small axons,
which are limited by the long diffusion times and the
significantly reduced sensitivity to small spatial
scales. OGSE has been shown to achieve much shorter
diffusion times and hence may be able to detect smaller
axons with high sensitivity. We measure the inner
diameters of hollow microcapillaries using OGSE methods.
Two ADC values are sufficient to extract the cylinder
diameters accurately. OGSE is insensitive to the
intrinsic diffusion coefficient in the relatively low
frequency range. We propose OGSE as a fast and robust
method for mapping axon sizes non-invasively.
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4418. |
7 |
Axon diameter distribution
(ADD) mapping of porcine spinal cord using d-PFG MRI ![](play.gif)
Dan Benjamini1,2, Michal E Komlosh1,3,
Uri Nevo2, and Peter J Basser1
1NIH, Bethesda, MD, United States, 2Tel
Aviv University, Tel Aviv, Israel, 3USUHS,
Bethesda, MD, United States
Noninvasive estimation of a non-parametric axon diameter
distribution (ADD) provides sub-voxel microstructural
information of white matter tissue. ADD infers on the
nerve conductivity, and is influenced by several
diseases, such as amyotrophic lateral sclerosis and
multiple sclerosis. A recently suggested 2D double
pulsed-field gradient MRI experiment is used on a
porcine spinal cord. A voxel-by-voxel non-parametric ADD
estimation provides a sub-voxel resolution map. Distinct
domains where the ADDs are similar are then found. ADD
estimation might prove to have clinical MRI applications
owing to its critical functional role in the central and
peripheral nervous systems, in normal and abnormal
tissue.
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4419. |
8 |
NMR characterization of
cylinder radii distributions using a SHORE-based
regularization method ![](play.gif)
Gonzalo Sanguinetti1, Matt G Hall2,
Daniel C Alexander2, and Rachid Deriche1
1Athena Project-Team, INRIA, Sophia-Antipolis,
France, 2Centre
for Medical Image Computing, Department of Computer
Science, University College London, London, United
Kingdom
We are interested in retrieving information about the
axon diameter distributions in white matter fiber
bundles using NMR, which are commonly modelled as
ensembles of parallel cylinders. We add regularization
to the 1D-SHORE basis which results in more stable
characterization of diameter distributions. To validate
the method, we simulate NMR signals using the open
source toolkit CAMINO. The results illustrate the
enhanced estimation accuracy given by the regularization
and provide an alternative validation of the SHORE based
method.
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4420. |
9 |
Mathematical models of
colorectal tumour microstructure informed by oscillating
gradients diffusion MRI ![](play.gif)
Alessandro Proverbio1, Bernard M. Siow2,3,
Eleftheria Panagiotaki3, Samuel Walker-Samuel2,
Mark F. Lythgoe2, Adam P. Gibson1,
and Daniel C. Alexander3
1Medical Physics and Bioengineering,
University College London, London, United Kingdom, 2Centre
for Advanced Biomedical Imaging, Division of Medicine,
University College London, London, United Kingdom, 3Centre
for Medical Image Computing and Department of Computer
Science, University College London, London, United
Kingdom
Investigation of tissue microstructure with non-invasive
histology is a developing research area. Diffusion MRI
(dMRI) can estimate features of microstructural
components such as cell cytoarchitecture. Here develop
signal models for Square Wave Oscillating Gradient Spin
Echo (SWOGSE) dMRI. This study is performed on fixed
subcutaneous xenograft tumour samples grown in nude
mice: 3 LS174T, and 3 SW1222 cell lines. Oscillating
Gradient Spin Echo probes shorter length scales than
standard PGSE. The more tissue-like compartment model
appears to represent the signal better, suggesting the
feasibility of a clinical measurement of cytological
properties of the tissue.
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4421. |
10 |
The Importance of Angular
Dispersion in Physiological Modeling of Transverse Diffusion
Signal Decay ![](play.gif)
Novena A Rangwala1, David B Hackney1,
and David C Alsop1
1Department of Radiology, Beth Israel
Deaconess Medical Center and Harvard Medical School,
Boston, Massachusetts, United States
In this theoretical study we have investigated the
effect of axonal dispersion in white matter on the
accuracy of physiological parameters estimated with a
diffusion model incorporating axonal dispersion into
AxCaliber. Diffusion signal decay was estimated with a
characteristic dispersion angle of 6°, at diffusion
times 20–1000 ms and two axonal diameter distributions,
and fit to AxCaliber equations without angular
dispersion. Results show that although AxCaliber can fit
the signal decay curves effectively, the fitted
parameters do not accurately match the assumed
physiological parameters. These results strongly suggest
that models of diffusion signal decay include axonal
dispersion, even in white matter tracts with
well-aligned fibers.
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4422. |
11 |
Changes in epithelium,
stroma, and lumen space predict ADC changes with prostate
cancer Gleason grade ![](play.gif)
Aritrick Chatterjee1, Geoff Watson2,
Esther Myint3, and Roger Bourne1
1Faculty of Health Sciences, University of
Sydney, Sydney, NSW, Australia, 2Tissue
Pathology and Diagnostic Oncology, Royal Prince Alfred
Hospital, Sydney, NSW, Australia, 3Laverty
Pathology, Sydney, NSW, Australia
Reduced water ADC in cancer tissue is commonly
attributed to “increased cellularity”, however, this
explanation includes many assumptions about the
diffusion properties of tissue. We hypothesise that the
biophysical basis of reduced ADC in prostate cancer may
instead lie in an increased partial volume of low
diffusivity epithelial cells and loss of higher
diffusivity stroma and lumen space. Partial volumes of
epithelium, stroma, and lumen space were measured in
histology images. There was a significant increase in
epithelium volume and decrease in stroma and lumen space
with Gleason grade. Predicted ADC changes explained
about half the variation seen in vivo.
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4423. |
12 |
Quantifying in-vivo changes
in myofiber diameter due to muscular atrophy with
time-dependent diffusion MRI ![](play.gif)
Gregory Lemberskiy1,2, Els Fieremans1,
Thorsten Feiweier3, Leon Axel1,
and Dmitry S Novikov1
1New York University School of Medicine,
Bernard and Irene Schwartz Center for Biomedical
Imaging, Department of Radiology, New York, NY, United
States, 2Sackler
Institute of Graduate Biomedical Sciences, New York
University School of Medicine, New York, NY, United
States, 3Siemens
AG, Healthcare Sector, Erlangen, Germany
The random permeable barrier model (RPBM) utilizes
time-dependent diffusion to quantify cell size and
membrane permeability. Human in-vivo RPBM validation was
performed on individuals that experienced calf muscle
atrophy while immobilized in a non-weight bearing cast.
The RPBM was used to quantify the difference of myofiber
size in immobilized and control calf muscles. Muscle
groups of immobilized calf muscles of all volunteers
were significantly smaller than those of the control
leg. Additionally, the RPBM revealed that certain muscle
groups atrophied less due to degrees of freedom offered
by the cast.
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4424. |
13 |
Diffusion modeling in brain
cell geometries parameterized according to morphometric
statistics
- permission withheld
Julien Valette1
1Molecular Imaging Research Center (MIRCen),
Commissariat à l'Energie Atomique, Fontenay-aux-Roses,
France
An original diffusion modeling approach is proposed to
capture some features of brain cells complexity and
heterogeneity, while parameterizing the model with only
a small set of parameters based on cell morphometric
statistics as derived from microscopy. We exemplify how
this approach allows evaluating the effect of long-range
cell morphology (i.e. cellular processes branching and
length) on the apparent diffusion coefficient (ADC) of
intracellular molecules, as might be measured by
diffusion-weighted MRI/spectroscopy at long diffusion
times Td.
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4425. |
14 |
Inverse Laplace transform
analysis of the DWI MRI signal in prostate and bladder ![](play.gif)
Milica Medved1, Shiyang Wang1,
Steffen Sammet1, Ambereen Yousuf1,
Gregory S Karczmar1, and Aytekin Oto1
1Radiology, University of Chicago, Chicago,
Illinois, United States
The non-mono-exponential nature of the DWI signal decay
in the prostate is well established. Current advanced
modeling methods use a two component model, and the data
is fit for the fast (corresponding to the coherent
motion in blood vessels) and slow (describing the
inherent diffusion properties of the glandular tissue)
components. Using a new implementation of the inverse
Laplace transform, we present evidence that multiple
slow components can be present in the decaying DWI
signal. We demonstrate evidence for single-component
diffusion in the bladder, and for presence of up to
three components in the peripheral zone of the prostate.
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4426. |
15 |
3D structure tensor
analysis of light microscopy data for validating diffusion
MRI ![](play.gif)
Ahmad Raza Khan1,2, Lindsey A Leigland3,
Steven G Kohama1, Anda Cornea1,
Sune Nørhøj Jespersen4, and Christopher D
Kroenke1,2
1Division of Neuroscience, Oregon National
Primate Research Center, Oregon Health & Science
University, Beaverton, Oregon, United States, 2Advanced
Imaging Research Center, Oregon Health & Science
University, Portland, Oregon, United States, 3Advanced
Imaging Research Center, Oregon Health & Science
University, Beaverton, Oregon, United States, 4Center
of Functionally Integrative Neuroscience, Aarhus
University Hospital, Aarhus, Denmark
Recently, two-dimensional structure tensor (ST) analysis
has been applied to light microscopy images for the
purpose of validating diffusion anisotropy measurements.
The ST analysis strategy enables the microscopy data to
be analyzed in a high-throughput manner, and hence is
suitable for group-comparison studies. However, 2D
analyses are restricted to directions parallel to the
imaging plane. Here we show it is possible to extend ST
analyses to 3D using serial image "stacks" acquired with
confocal microscopy of nonhuman primate brain tissue. It
is expected that this generalization of the ST analysis
will extend its range of applications in future studies.
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4427. |
16 |
A novel method for
realistic DWI data generation ![](play.gif)
Daniele Perrone1, Jan Aelterman1,
Ben Jeurissen2, Aleksandra Pizurica1,
Wilfried Philips1, and Jan Sijbers2
1IPI-TELIN-IMINDS, University of Gent, Gent,
East Flanders, Belgium, 2Vision
Lab, University of Antwerp, Antwerp, Antwerp, Belgium
Diffusion Weighted Imaging (DWI) was introduced to
explore the human connectome in vivo; although many
fiber tractography (FT) algorithms exist, proving the
effectiveness of their estimates is challenging. We
present a biologically and physically realistic software
phantom, with brain-like fibres configuration and
images, fully tunable in terms of ‘simulated
acquisition’ parameters: a realistic bench test for
quantitative analyses of every DWI-related algorithm.
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4428. |
17 |
Methods for comparing fiber
orientation distribution (FOD) functions based on histology
and diffusion MRI ![](play.gif)
Yurui Gao1, Ann Choe2, Iwona
Stepniewskwa3, Xia Li2, and Adam W
Anderson4
1VUIIS, Vanderbilt University, Nashville,
Tennessee, United States, 2VUIIS,
Vanderbilt University, TN, United States, 3Psychology,
Vanderbilt University, TN, United States, 4BME,
Vanderbilt University, TN, United States
In previous studies, we validated
DTI-tractography-derived connectivity by comparing with
the histological ground truth. Because DTI fiber
orientation estimation is the basis of tractography,
juxtaposing the DTI fiber orientation distribution
(dFOD) and histological FOD (hFOD) is critical to
validation studies. However, obtaining the 3D hFOD is
challenging. This study introduces 1) two methods to
extract the hFOD from z-stack micrographs and 2) the
procedure to compare dFOD with hFOD functions.
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4429. |
18 |
NAA spectroscopy correlates
with intra-axonal compartment parameters from diffusion MRI ![](play.gif)
Elan J. Grossman1,2, Ivan I. Kirov1,
Oded Gonen1, Dmitry S. Novikov1,
Robert I. Grossman1, Matilde Inglese3,
and Els Fieremans1
1Center for Biomedical Imaging, Department of
Radiology, NYU School of Medicine, New York, New York,
United States, 2Department
of Physiology and Neuroscience, NYU School of Medicine,
New York, New York, United States, 3Department
of Neurology, Radiology, and Neuroscience, Mount Sinai
School of Medicine, New York, New York, United States
The relationship between compartment-specific white
matter tract integrity (WMTI) parameters from diffusion
MRI and concentrations of neurochemicals was
investigated in vivo using 1H-MRS on a cohort of
patients with mild traumatic brain injury (MTBI).
Results demonstrated significant correlations
associating n-acetylaspartate (NAA) with those WMTI
parameters that are affected by intra-axonal diffusion
and axonal density, suggesting the validity of a
two-compartment non-exchange model of intra- and
extra-axonal diffusion in a single WM fiber bundle. Our
results also indicate that NAA may influence downstream
processes related to axonal shrinkage, degeneration,
and/or loss, as well as plasma osmolarity and myelin
synthesis in MTBI.
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4430. |
19 |
Quantifying non-invasive
MRI parameters with angiogenesis and cellular infiltration
to characterize collagen-sponge remodeling ![](play.gif)
Mohammed Salman Shazeeb1,2, Sivakumar
Kandasamy2, Stuart Howes2, and
George Pins2
1Radiology, University of Massachusetts
Medical School, Worcester, MA, United States, 2Biomedical
Engineering, Worcester Polytechnic Institute, Worcester,
MA, United States
Invivo evaluation of biomaterial implant remodeling
involves surgical removal of the implant for subsequent
histological assessment. This approach is often
destructive and imposes practical limitations on how
effectively these materials can be evaluated. MRI has
the potential to non-invasively monitor the remodeling
of collagen scaffolds. This study investigated the
development of a model system to quantify MRI parameters
with angiogenesis and cellular infiltration of implanted
collagen scaffolds using MRI and histological
techniques. Correlations between MRI and histological
parameters demonstrated that MRI is sensitive to
specific remodeling parameters which can aid in the
design of robust biomaterial scaffolds for tissue
regeneration.
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4431. |
20 |
Integrated Phantom Analysis
of Perfusion, Diffusion, and Fluctuation MRI
- permission withheld
Naoki Ohno1, Tosiaki Miyati1,
Tomohiro Chigusa1, Hikaru Usui1,
Noam Alperin2, Shinnosuke Hiratsuka1,
Akihiro Asano1, Hirohito Kan3,
Satoshi Kobayashi1, Toshifumi Gabata1,
and Osamu Matsui1
1Kanazawa University, Kanazawa, Japan, 2University
of Miami, FL, United States, 3Nagoya
City University Hospital, Nagoya, Japan
To clarify relations and mechanisms among
blood-perfusion, water-diffusion, water-fluctuation, and
biomechanics of the intracranial tissue, we developed an
original cranial phantom for magnetic resonance imaging.
The new cranial phantom consisted of a high-density
polypropylene filter with intra- and extra-filter
spaces, and a capacitor space, which were filled with
water at 17 degrees centigrade. These correspond to a
brain parenchyma, artery and vein, and cerebrospinal
fluid space, respectively. Our original phantom makes it
possible to clarify relations and mechanisms among
blood-perfusion, water-diffusion, water-fluctuation, and
biomechanics of intracranial tissue. Perfusion,
diffusion, fluctuation, and biomechanics of the
intracranial tissue interact in diverse ways.
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4432. |
21 |
Magnetic Resonance
Microscopy of the Drosophila Brain at 10 Micron Isotropic
Resolution
- permission withheld
Choong Heon Lee1,2, Stephen J Blackband1,2,
and Fernandez-Funez Pedro1,3
1Neuroscience, University of Florida,
Gainesville, FL, United States, 2McKnight
Brain Institute, Gainesville, FL, United States, 3Neurology,
University of Florida, FL, United States
Understanding the complex brain architecture and
functional connectivity using MRI has been a major
interest in neuroscience. Based on the capability of MR
microscopy to visualize the mammalian and human cells,
the desire to map the entire human brain circuit at the
resolution high enough to visualize cell-level
structures is becoming a reality. Studies of a simpler
brain, i.e. Drosophila, are significant due to its high
genetic tractability together with high degree of
conservation with humans at the genetic and cellular
levels. To visualize the neuronal circuitry in the
brain, we acquired MRM of it at 10 µm isotropic
resolution.
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4433. |
22 |
In-Bore Oxygenator Designed
for Physiological Maintenance of Slice and Cell Culture
Preparations Employed in MR Microscopy Studies ![](play.gif)
Jeremy J Flint1,2, Kannan M Menon2,3,
Brian Hansen4, and Stephen J Blackband1,5
1Neuroscience, University of Florida,
Gainesville, Florida, United States, 2McKnight
Brain Institute, University of Florida, Gainesville,
Florida, United States,3Biomedical
Engineering, University of Florida, Gainesville,
Florida, United States, 4Center
for Functionally Integrative Neuroscience, Aarhus
University, Aarhus, Denmark, 5National
High Magnetic Field Laboratory, Florida State
University, Tallahassee, Florida, United States
Recent developments allowing direct visualization of
cellular structure in excised mammalian tissue using MRI
techniques have created a need for micro-perfusion
equipment capable of operating in conjunction with
high-field spectrometer hardware. This study details the
design and fabrication of an in-bore oxygenator capable
of offering precise control of perfusate properties
including pH and dissolved gas (O2 &
CO2) content. In addition, a stability
assessment is conducted which compares diffusion signal
reproducibility over time under conditions of constant
perfusion as compared to a static control group.
Findings indicate statistical equivalence at 13 of 14
time-points sampled over a 21 hour period.
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4434. |
23 |
In Vivo Observation of
Time-Dependent Diffusion in White Matter in Humans ![](play.gif)
Lauren Burcaw1, Jelle Veraart2,
Dmitry S Novikov1, and Els Fieremans1
1New York University School of Medicine,
Bernard and Irene Schwartz Center for Biomedical
Imaging, Department of Radiology, New York, NY, United
States, 2Vision
Lab, Department of Physics, University of Antwerp,
Antwerp, Belgium
We report on time-dependent diffusion in white We report
on time-dependent diffusion in white matter as measured
on three normal human volunteers over diffusion times
ranging from 26 to 400 ms. A decrease in axial
diffusivity with time is found indicating the presence
of restrictions to diffusion along the axonal direction.
We also note a decrease in radial diffusion with respect
to time, however this decrease is less pronounced. Our
results imply that axial and possibly radial
time-dependent diffusion may be observable using
clinical systems.
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4435. |
24 |
Magnetic resonance
microscopy of fixed breast tissue
- permission withheld
Narina Norddin1,2, Ned Charles1,
Nyoman Kurniawan3, Gary Cowin3,
Laurence Gluch4, Carl Power5,
Geoffrey Watson6, and Roger Bourne1
1Faculty of Health Sciences, University of
Sydney, Camperdown, NSW, Australia, 2Kulliyyah
of Allied Health Sciences, International Islamic
University Malaysia, Kuantan, Pahang, Malaysia, 3University
of Queensland, Brisbane, Queensland, Australia, 4The
Strathfield Breast Centre, Strathfield, NSW, Australia, 5University
of New South Wales, Sydney, NSW, Australia, 6Royal
Prince Alfred Hospital, Sydney, NSW, Australia
Conventional MRI has high sensitivity for breast cancer
detection but poor specificity.Addition of DWI to a
breast exam may increase specificity to around
90%.However,the biophysical basis of changes in
diffusion weighted contrast in the breast and other
non-neural tissue remains poorly understood.The study
described here investigates the microscopic diffusion
properties of formalin fixed breast tissue.Breast tissue
glandular epithelium is similar to prostate tissue
epithelium in having a low ADC relative to adjacent
tissue.Low ADC may be a distinctive and diagnostically
useful feature of glandular epithelia,not only in
prostate and breast,particularly considering that 80-90%
of all cancers are of epithelial origin.
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ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Diffusion: Acquisition Strategies
Wednesday 14 May 2014
Exhibition Hall |
13:30 - 14:30 |
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Computer # |
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4436. |
25 |
Asymmetric Two-Dimensional
Spatially Selective Excitation in Echo-Planar Imaging ![](play.gif)
Rainer Schneider1,2, Jens Haueisen2,
and Josef Pfeuffer1
1MR Application Development, Siemens
Healthcare, Erlangen, Bavaria, Germany, 2Institute
of Biomedical Engineering and Informatics, TU Ilmenau,
Ilmenau, Thuringia, Germany
An asymmetric design is introduced to 2-D spatially
selective radiofrequency (2DRF) pulses based on an
echo-planar trajectory. The proposed design allows a
significant reduction of pulse durations maintaining the
excitation quality. This can be done independent of
potential pulse accelerations with parallel
transmission. Excitation quality with different
asymmetry factors was analyzed in a phantom study.
Asymmetric 2DRF pulses were evaluated in human
diffusion-weighted experiments. Linked to the resulting
TE savings, asymmetric 2DRF pulses offered SNR gains of
up to 25% compared to the conventional 2DRF designs.
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4437. |
26 |
Reduced field-of-view
diffusion with 2D echo-planar RF excitation and Multiband
refocusing for extended slice coverage and robust fat
suppression ![](play.gif)
Suchandrima Banerjee1, Emine Ulku Saritas2,3,
Rachel Connett1, and Ajit Shankaranarayanan1
1Global Applied Science Laboratory, GE
Healthcare, Menlo Park, California, United States, 2Department
of Electrical and Electronics Engineering, Bilkent
University, Bilknet, Ankara, Turkey, 3National
Magnetic Resonance Research Center, Bilknet University,
Bilknet, Ankara, Turkey
Reduced field-of-view (rFOV) single-shot echo-planar
imaging (ssEPI) with 2D Echo-planar (EP) RF excitation
can improve diffusion image quality and enable high
resolution, by reducing distortion. However slice
coverage can be limited because of periodic repetitions
of the excitation sidelobes appearing along the slice
direction. We propose to address this constraint by
using a multiband refocusing scheme that will
simultaneously refocus multiple excitation lobes. Signal
from the simultaneously refocused slice locations can be
separated using parallel imaging method. We demonstrate
that by using multiband refocusing with 2D EPRF in ssEPI,
slice coverage can be increased while preserving rFOV
and fat suppression.
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4438. |
27 |
Correcting for B1
inhomogeneities in post-mortem DWSSFP human brain data at 7T
using multiple flip angles ![](play.gif)
Sean Foxley1, Saad Jbabdi1, Stuart
Clare1, and Karla Miller1
1FMRIB Centre, University of Oxford, Oxford,
OXON, United Kingdom
Due to the comparably sized RF wavelength at 7T, human
brain imaging suffers from a central ‘bright spot’.
Here, we investigated the implementation of a multiple
flip angle approach to account for this B1 dependent
artifact. Data were acquired at 7T of post-mortem human
brain using a diffusion weighted steady-state free
precession pulse sequence. Two flip angles were chosen
using a described optimization method and DTI data were
acquired using both. Results demonstrate that the
primary diffusion direction was more accurately
estimated in gray matter where signal loss due to B1
decreases have made this otherwise difficult to detect.
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4439. |
28 |
Three-Dimensional
Diffusion-Prepared Balanced Steady-State Free Precession
with Variable Flip Angle Scheme ![](play.gif)
Yuji Iwadate1, Mitsuharu Miyoshi1,
and Hiroyuki Kabasawa1
1Global MR Applications and Workflow, GE
Healthcare Japan, Hino, Tokyo, Japan
In diffusion preparation methods, the k-space signal
modulation by T1 recovery results in image degradation
if its effect is not negligible. We developed 3D
diffusion-prepared balanced steady-state free precession
pulse sequence with a variable flip angle technique to
correct for the T1 recovery effects during data
acquisition. In both simulation and phantom scan,
variable flip angle reduced edge enhancement effect when
we used centric view ordering. This technique can lead
to homogeneous 3D diffusion weighted image acquisition
of subjects with short T1 recovery times.
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4440. |
29 |
Acoustic noise optimized
Diffusion-Weighted Imaging (DWI) ![](play.gif)
Martin Ott1, David Porter2, Felix
Breuer1, David Grodzki2, Martin
Blaimer1, Björn Heismann2, and
Peter Jakob1,3
1MRB Forschungszentrum für
Magnet-Resonanz-Bayern e.V., Würzburg, Bavaria, Germany, 2Siemens
AG, Erlangen, Bavaria, Germany, 3Department
of Experimental Physics 5, University of Wuerzburg,
Würzburg, Germany
Diffusion-Weighted Imaging (DWI) is one of the loudest
and most challenging sequence in terms of acoustic-noise
due to the requirement of strong and fast switching
gradients. In this work, among other gradient
optimizations, a rs-EPI readout is modified to
consequently minimize slew rates and hence
acoustic-noise. Methodical modifications are presented
as well as corresponding acoustic-noise measurements. A
significant reduction in acoustic-noise of over 15dB(A)
could be achieved. In-vivo imaging results are compared
to standard methods like single-shot EPI.
|
4441. |
30 |
Improve Image Homogeneity
of High-Resolution DWI
Jiazheng Wang1 and
Yongchuan Lai2
1STO-MR, GE Healthcare, Beijing, Beijing,
China, 2GE
Healthcare, Beijing, China
EPI based diffusion imaging is widely used yet suffers
from geometric distortions, which become more pronounced
in high resolution imaging. This work presents a method
to implement 2D excitation for high-resolution EP-DWI
with reduced phase encoding FOV, and thus to reduce the
geometric distortion. Comparing to prior-art technique,
the 2D excitation in this work is equipped with a pair
of walking-saturations, which can improve the excitation
profile in the phase encoding FOV direction and get more
homogeneous imaging results. The proposed method is also
shown to increase the max number of slices per TR
comparing to traditional 2D excitation.
|
4442. |
31 |
Updating Shim Dynamically
During Diffusion Tensor Imaging Acquisition ![](play.gif)
A. Alhamud1, Aaron T. Hess2, Paul
A. Taylor1,3, Ernesta M. Meintjes1,
and André J.W. van der Kouwe4
1Human Biology,MRC/UCT Medical Imaging
Research Unit, University of Cape Town, Cape Town,
Western Cape, South Africa, 2University
of Oxford, Oxford, United Kingdom, 3African
Institute for Mathematical Sciences, Western Cape, South
Africa, 4Massachusetts
General Hospital, Charlestown, Massachusetts, United
States
Diffusion tensor imaging (DTI) is characterized by a
long acquisition time in which B0 homogeneity may change
from one TR to another, or from one DTI scan to another
due to many factors especially if head position changes
(e.g. acquiring DTI in two different phase encoding
directions ‘AP and PA’ ). Several studies have focused
on evaluating the changes in B0 for fMRI, but this issue
has been largely neglected for DTI. In this work, we
present the first study to measure, report and correct
the inhomogeneity in the static field with simultaneous
real time shim correction,TR-by-TR, in real time.
|
4443. |
32 |
Diffusion Weighted Imaging
of In-vivo heart with 2nd moment nulling diffusion gradient ![](play.gif)
Tetsuo Ogino1,2, Toshiaki Miyati3,
Marc Van Cauteren4, Tomoya Nakamura5,
Taro Takahara6, and Yutaka Imai6
1Healthcare department, Philips Electronics
Japan, LTD, Minato-ku, Tokyo, Japan, 2division
of Health Sciences, Kanazawa University, Kanazawa,
Ishikawa, Japan, 3Kanazawa
University, Kanazawa, Ishikawa, Japan, 4Philips
Healthcare LTD, Tokyo, Japan, 5Tokai
University Hospital, Kanagawa, Japan, 6Tokai
University, Kanagawa, Japan
A second moment nulling on diffusion gradients combined
with ECG triggering for in-vivo myocardial diffusion
weighted imaging was investigated its clinical
feasibility. Uniform DWI signal was obtained with
b-factor = 500 s/mm2 and clinically acceptable image
quality with moderate signal non-uniformity was achieved
up to b=800 s/mm2.
|
4444. |
33 |
POCS-ICE: POCS based
Inherent Correction of phase Errors for multi-shot spiral
DWI ![](play.gif)
Xiaodong Ma1, Feng Huang2, Zhe
Zhang1, Bida Zhang2, Sheng Fang3,
and Hua Guo1
1Center for Biomedical Imaging Research,
Department of Biomedical Engineering, School of
Medicine, Tsinghua University, Beijing, Beijing, China, 2Philips
Research China, Beijing, China, 3Institute
of nuclear and new energy technology, Tsinghua
University, Beijing, China
POCS based Inherent Correction of motion-induced phase
Errors (POCS-ICE) is proposed for the reconstruction in
multi-shot spiral DWI, which can automatically correct
the phase variation among different excitations without
calculating them directly. Invivo experiments show that
DW images from POCS-ICE present higher SNR and less
aliasing artifacts than SENSE+CG when a large shot
number is used. Therefore, it can contribute to
shortening the spiral readout duration such that high
resolution diffusion weighted images can be achieved.
|
4445. |
34 |
Self-feeding MUSE: A Method
for High Resolution Diffusion Weighted Imaging with Robust
Phase Variation Estimation ![](play.gif)
Zhe Zhang1, Feng Huang2, Bida
Zhang3, Sheng Fang4, and Hua Guo1
1Center for Biomedical Imaging Research,
Department of Biomedical Enginnering, School of
Medicine, Tsinghua University, Beijing, China, 2Philips
Healthcare, Gainesville, FL, United States, 3Philips
Research China, Beijing, China, 4Institute
of Nuclear and New Energy Technology, Tsinghua
University, Beijing, China
Multi-shot strategies have been used for improving
spatial resolution of DWI. MUSE is a multi-shot EPI
based DWI method using SENSE for self-navigating of each
shot. When many shots are used to decrease the EPI
distortion and blurring, high SENSE reduction factor
will cause inaccurate phase estimation and thus ghost
artifacts. In this work, Self-feeding MUSE is proposed
for robust phase estimation and improved MUSE
reconstruction, even if the number of shots is high.
|
4446.
![](MAGNA25.jpg) |
35 |
FAST MOTION-COMPENSATED ODF
RECONSTRUCTION FROM UNDER-SAMPLED MULTI-CHANNEL MULTI-SHOT
NON-CARTESIAN DIFFUSION IMAGING DATA AT HIGH ANGULAR AND
SPATIAL RESOLUTION ![](play.gif)
Merry Mani1, Mathews Jacob2,
Vincent Magnotta2, and Jianhui Zhong1
1University of Rochester, Rochester, NY,
United States, 2University
of Iowa, Iowa, United States
Applications such as the study of human brain
connectivity and pre-surgical planning can greatly
benefit from high angular and spatial resolution
diffusion data. Non-Cartesian multi-shot diffusion
imaging schemes can offer high spatial resolution
diffusion images. Coupled with high angular resolution
schemes, it can enable the reconstruction of high
fidelity fiber tracts. However, non-Cartesian multi-shot
image reconstruction can be prohibitively time-consuming
because of the need to account for motion-induced phase
terms in the reconstruction to avoid motion artifacts. A
fast reconstruction scheme is proposed using a PCA-based
approximation, to accelerate the motion-compensated
reconstruction of high angular and spatial resolution
diffusion data.
|
4447. |
36 |
High-quality and
High-throughput Interleaved Diffusion Weighted EPI Enabled
by Multi-band Multiplexed Sensitivity Encoding (MUSE) and
Adaptive Partial Fourier Reconstruction ![](play.gif)
Hing-Chiu Chang1, Shayan Guhaniyogi1,
and Nan-Kuei Chen1
1Brain Imaging and Analysis Center, Duke
University Medical Center, Durham, North Carolina,
United States
Multiplexed sensitivity encoding (MUSE) can effectively
remove aliasing artifact due to shot-to-shot phase
inconsistencies without relying on navigator echo.
However, the conventional partial Fourier reconstruction
procedure included in the original MUSE is highly
susceptible to motion-induced k-space energy peak
displacement, and the imaging throughput of multi-shot
MUSE is significantly lower than single-shot DWI. We
first develop a novel adaptive partial Fourier
reconstruction procedure capable of producing
high-quality multi-shot DWI, even in the presence of
motion-induced k-data energy displacement. Next, we
generalize the MUSE reconstruction to accommodate
multi-band data, so that high-throughput,
high-resolution and high-quality DWI can all be
simultaneously achieved.
|
4448. |
37 |
Clinically Feasible NODDI
Characterization of Brain Tumor in 5.5 minutes Using
Multiband EPI at 7T ![](play.gif)
Qiuting Wen1,2, Douglas A.C. Kelley3,
Suchandrima Banerjee4, Janine M. Lupo2,
Duan Xu2, Christopher P. Hess2,
and Sarah J. Nelson1,2
1Graduate Program in Bioengineering,
University of California, San Francisco & Berkeley, San
Francisco, CA, United States, 2Radiology
and Biomedical Imaging, University of California, San
Francisco, San Francisco, CA, United States, 3Global
Applied Science Laboratory, GE healthcare, San
Francisco, CA, United States, 4Global
Applied Science Laboratory, GE healthcare, Menlo Park,
CA, United States
The goal of this study was to demonstrate the
feasibility of acquiring 7T data suitable for NODDI in
under 6 minutes with a tailored multiband technique for
routine clinical application. In a brain tumor patient
NODDI provided unique contrast within the T2 lesion.
Although NODDI does not directly model tumor
characteristics, it demonstrates great potential in
revealing underlying tissue components that are
complimentary to FA and ADC. With the multiband EPI
technique, we reduced the acquisition time of this
two-shell diffusion sequence to 5.5 minutes, making it
clinically feasible. In addition to NODDI, both
diffusion tensor and tractography data can also be
generated from this protocol.
|
4449. |
38 |
Accelerated human cardiac
diffusion tensor imaging using simultaneous multi-slice
imaging ![](play.gif)
Angus Z. Lau1,2, Elizabeth M. Tunnicliffe1,
Robert Frost3, Peter J. Koopmans3,
Damian J. Tyler1,2, and Matthew D. Robson1
1Department of Cardiovascular Medicine,
University of Oxford, Oxford, United Kingdom, 2Department
of Physiology, Anatomy, and Genetics, University of
Oxford, Oxford, United Kingdom, 3FMRIB
Centre, University of Oxford, Oxford, United Kingdom
Remodeling of cardiac fibre structure contributes to
impaired cardiac function, and is implicated in the
development of cardiac arrhythmias and sudden cardiac
death. Diffusion tensor imaging (DTI) allows
non-invasive detection of microstructure in vivo, but
low SNR leads to long scan times, limiting the patient
population which can benefit from such exams. In this
abstract, we investigate the feasibility of using
simultaneous multi-slice (SMS) excitation to accelerate
human DTI of the heart. We demonstrate three-fold scan
time reduction of cardiac diffusion measurements, and we
anticipate this development will make it practical to
incorporate DTI within a comprehensive clinical exam.
|
4450. |
39 |
An Information Theoretic
Approach to Optimal Q-space Sampling ![](play.gif)
Hans Knutsson1 and
Carl-Fredrik Westin2,3
1Biomedical Engineering, CMIV, Linköping,
Östergötland, Sweden, 2Harvard
Medical School, MA, United States, 3Linköping
University, Östergötland, Sweden
We present a novel approach to determine a local q-space
metric that is optimal from an information theoretic
perspective with respect to the expected signal
statistics. The obtained metric will then serve as a
guide for the generation of specific q-space sample
distributions. It should be noted that the approach
differs significantly from the classical estimation
theory approach, e.g. one based on Cramer-Rao bounds.
The basis for finding the q-space metric is to compute
the information gain from measuring at a second q-space
location given that we already have information from a
first location.
|
4451. |
40 |
Sparse isotropic q-space
sampling distribution for Compressed Sensing in DSI ![](play.gif)
Alexandra Tobisch1,2, Gabriel Varela3,
Rüdiger Stirnberg1, Hans Knutsson4,
Thomas Schultz2,5, Pablo Irarrázaval3,6,
and Tony Stöcker1
1German Center for Neurodegenerative Diseases
(DZNE), Bonn, Germany, 2University
of Bonn, Bonn, Germany, 3Biomedical
Imaging Center, Pontificia Universidad Católica de
Chile, Santiago, Metropolitan District, Chile, 4Linköping
University, Linköping, Sweden, 5MPI
for Intelligent Systems, Tübingen, Germany, 6Department
of Electrical Engineering, Pontificia Universidad
Católica de Chile, Santiago, Metropolitan District,
Chile
The Compressed Sensing (CS) technique accelerates
Diffusion Spectrum Imaging (DSI) through sub-Nyquist
sampling in q-space and subsequent nonlinear
reconstruction of the diffusion propagator.
State-of-the-art DSI approaches that exploit CS apply
Cartesian undersampling patterns. Recently, a method was
proposed to generate 3D non-Cartesian sample
distributions that aim for isotropic sampling of
q-space. This work compares the new scheme to standard
Cartesian undersampling patterns in sparse
reconstruction of simulated diffusion signals. The
diffusion propagator and the corresponding orientation
distribution function of the reconstruction are found to
deviate less from the ground truth when using an
isotropic q-space sample distribution.
|
4452. |
41 |
Optimizing Q-Space Sampling
Density for Diffusion Spectrum Imaging ![](play.gif)
Qiyuan Tian1, Ariel Rokem2, Brian
L. Edlow3, Rebecca D. Folkerth4,
and Jennifer A. McNab5
1Department of Electrical Engineering,
Stanford University, Stanford, CA, United States, 2Department
of Psychology, Stanford University, Stanford, CA, United
States, 3Department
of Neurology, Massachusetts General Hospital, Boston,
MA, United States, 4Department
of Pathology, Brigham and Women's Hospital, Boston, MA,
United States, 5Department
of Radiology, Stanford University, Stanford, CA, United
States
Diffusion spectrum imaging is an approach to
characterizing complex tissue microstructure. Stronger
gradients enable expanded q-space coverage, which
improves the spin-displacement resolution but also
increases the q-space sampling density requirements.
Here, we show three datasets acquired on a whole, fixed,
human brain acquired with 300mT/m maximum gradients.
These data are used to examine the effects of q-space
sampling density on the fidelity of the voxel-wise
orientation distribution functions (ODFs). Specifically,
we show there is trade-off between ODF sharpness and
aliasing artifacts when sampling density is insufficient
to capture the spin-displacement pattern.
|
4453. |
42 |
Rotating Field Gradient (RFG)
Diffusion MRI for Mapping 3D Orientation Distribution
Functions (ODFs) in the Human Brain ![](play.gif)
Alexandru V Avram1, Joelle E Sarlls2,
Peter J Basser1, and Evren Ozarslan3
1Section on Tissue Biophysics and
Biomimetics, NICHD, National Institutes of Health,
Bethesda, MD, United States, 2NINDS,
National Institutes of Health, Bethesda, MD, United
States, 3Department
of Radiology, Brigham and Women's Hospital, Harvard
Medical School, Boston, MA, United States
Conventional methods for mapping 3D diffusion
orientation distribution functions (dODFs) of neuronal
microstructure require long acquisitions and are prone
to quantitation errors due to subject motion. In this
study we describe a method for directly measuring in
vivo 3D dODFs with a novel technique called Rotating
Field Gradient (RFG) diffusion MRI, which applies
sinusoidal diffusion gradients in arbitrarily oriented
planes to directly sample the dODFs along the axis of
rotation. RFG dMRI represents a fast, direct and
model-free method for mapping 3D ODFs that could
represent a powerful alternative to conventional
pulse-field gradient diffusion MRI techniques.
|
4454. |
43 |
What do we gain from
multiple q-shell acquistions in high angular resolution
diffusion imaging?
- permission withheld
Jonas Cordes1, Peter Neher1,
Hans-Peter Meinzer1, Bram Stieltjes2,
and Klaus Maier-Hein1,2
1Medical and Biological Informatics, German
Cancer Research Center (DKFZ), Heidelberg,
Baden-Württemberg, Germany, 2Quantitative
Image-based Disease Characterization, German Cancer
Research Center (DKFZ), Heidelberg, Baden-Württemberg,
Germany
Here we present a set of metrics and experiments that
evaluate the performance of several single- and
multi-shell high angular resolution diffusion imaging
(HARDI) acquisition schemes. In particular, we assess
the angular resolution, the peak accuracy, the peak
precision as well as the distribution function accuracy
and distribution function precision at several different
fiber configurations. We show that low b-value
acquisitions in a multi-shell configuration can reach
similar performances as high b-value acquisitions on a
single shell.
|
4455. |
44 |
Probing white matter
microstructure at high spatial resolution combining CHARMED
protocol optimization and a high performance gradient set ![](play.gif)
Matteo Bastiani1, Silvia De Santis2,3,
Derek Jones2,3, Yaniv Assaf4, and
Alard Roebroeck1
1Department of Cognitive Neuroscience,
Maastricht University, Maastricht, Limburg, Netherlands, 2CUBRIC,
School of Psychology, Cardiff University, Cardiff,
United Kingdom, 3Neuroscience
and Mental Health Research Institute, Cardiff
University, Cardiff, United Kingdom, 4Department
of Neurobiology, The George S. Wise Faculty of Life
Sciences, Tel Aviv University, Tel Aviv, Israel
The composite hindered and restricted model of diffusion
(CHARMED) typically requires multiple acquisitions with
high b-values and high angular resolution, both of which
are difficult to obtain with clinical MRI systems. The
purpose of this study is to investigate the feasibility
of probing white matter microstructure at high spatial
resolution in vivo at 3T, combining protocol
optimization and a high amplitude, high slew-rate
gradient set. Different levels of trade-off between
resolution, SNR and diffusion contrast are compared and
the results are further compared to a benchmark dataset
obtained from the Human Connectome Project (HCP).
|
4456. |
45 |
Diffusion tensor imaging
with 1mm isotropic resolution using a dual-echo steady-state
method at 3T ![](play.gif)
Vincent Gras1, Ezequiel Farrher1,
Farida Grinberg1, and N Jon Shah1,2
1INM-4, Research Centre Jülich GmbH, Jülich,
Germany, 2Department
of Neurology, RWTH Aachen University, Aachen, Germany
We investigate the applicability of the dual echo steady
state pulse sequence with diffusion-weighting field
gradients (DW-DESS) to characterize the anisotropic
diffusion of water molecules in a dedicated anisotropic
diffusion fibre phantom. The conventional diffusion
tensor imaging (DTI) model is used for the data analysis
and a comparison with the gold standard pulse sequence
for DTI, namely the DW spin-echo EPI sequence, is
carried out. A good agreement between both pulse
sequences is demonstrated. Finally the feasibility of
applying DW-DESS for high resolution DTI in
vivo is
discussed.
|
4457. |
46 |
Effect of Diffusion Time on
Intravoxel Incoherent Motion Parameters in Abdominal Organs ![](play.gif)
Yeeliang Thian1, Matthew R. Orton2,3,
David J. Collins2,3, James A. d'Arcy2,3,
Martin O. Leach2,3, Thorsten Feiweier4,
and Dow-Mu Koh1
1Department of Radiology, Royal Marsden
Hospital, Sutton, Surrey, United Kingdom, 2CR-UK
and EPSRC Cancer Imaging Centre,Institute of Cancer
Research UK, Surrey, United Kingdom, 3Royal
Marsden Hospital, Surrey, United Kingdom, 4Siemens
AG, Healthcare Sector, Erlangen, Germany
The intra-voxel incoherent motion (IVIM) model relates
signal decay on diffusion-weighted MRI (DWI) to tissue
characteristics of perfusion and diffusivity. We
explored the effects of altering the diffusion time of
DWI sequences on IVIM perfusion (f,D*) and diffusion (D)
related parameters in abdominal organs of healthy
volunteers. At longer diffusion times, the calculated
perfusion fraction (f) was significantly increased while
the effect on the D and D* parameters was more variable,
depending on the organ under study. The diffusion time
has a significant impact on measured IVIM parameters in
abdominal organs and should be reported when employing
the IVIM model.
|
4458. |
47 |
Prostate MRI : comparison
of generalized autocalibrating partial parallel acquisition
(GRAPPA) -accelerated readout-segmented echo-planar imaging
(EPI) and single-shot EPI in clinical application of
diffusion-weighted imaging at 3 T
Liang Li1, Liang Wang1, Hui Liu2,
Ming Deng1, Zhao-Yan Feng1, and Ji-Hong
Liu3
1Department of Radiology, Tongji Hospital,
Tongji Medical College, Huazhong University of Science
and Technology, wuhan, hubei, China, 2Siemens
Healthcare, Shanghai, China, 3Department
of Urology, Tongji Hospital, Tongji Medical College,
Huazhong University of Science and Technology, wuhan,
hubei, China
In this study, we investigate the use of
readout-segmented echo planar imaging(rs-EPI) for
diffusion imaging of the prostate. This result show the
rs-EPI sequence will be less affected by both chemical
shift and magnetic susceptibility resulting in higher
quality images.
|
4459. |
48 |
Effects of duration of the
diffusion-encoding gradient ( )
and/or diffusion time interval ( )
in diffusion weighted MRI: assessing ADC and Kurtosis in
human brain ![](play.gif)
Shohei Miyazaki1, Masato Uchikoshi2,
Thorsten Feiweier3, Andre de Oliveira3,
Souichirou Tateishi1, Hitoshi Matsui1,
Takashi Horinouchi1, and Katsuyuki Nakanishi1
1Osaka Medical Center for Cancer and
Cardiovascular Diseases, Osaka, Osaka, Japan, 2SIEMENS
JAPAN K.K., Tokyo, Japan, 3SIEMENS
AG, Erlangen, Germany
We evaluated the effect of duration of the
diffusion-encoding gradient (ƒÂ) and/or diffusion time
interval (Ģ) in DW-MRI. DW-MRI were performed with
various ƒÂ or ƒ¢ in healthy volunteers and patients with
metastatic brain tumor, and the ADC and kurtosis were
estimated. In our results, the kurtosis was affected by
ƒ¢ more significant than ƒÂ, whereas there was no
significant change in ADC against to both of ƒÂ and ƒ¢.
Our results suggested that it might be important to
optimize the Ģ, leading usefulness in clinical
diagnosis and assessment of the treatment effect of
brain disease using kurtosis.
|
|
|
|
ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Diffusion Analysis
Wednesday 14 May 2014
Exhibition Hall |
13:30 - 14:30 |
|
|
|
Computer # |
|
4460. |
49 |
The importance of
correcting for B0-drift-induced global signal decrease in
diffusion MRI ![](play.gif)
Sjoerd B. Vos1, Chantal M.W. Tax1,
Fredy Visser2, Peter R. Luijten2,
Alexander Leemans1, and Martijn Froeling2
1Image Sciences Institute, University Medical
Center Utrecht, Utrecht, Utrecht, Netherlands, 2Department
of Radiology, University Medical Center Utrecht,
Utrecht, Utrecht, Netherlands
B0-drift-induced global signal decrease in DWI data
causes a significant influence on the estimation of
diffusion parameters. Quantitative diffusion metrics (FA
and mean kurtosis) as well as directional information
(first eigenvectors in DTI) are affected by this
artifactual signal decrease during the scan session. By
interspersing the non-diffusion-weighted images
throughout the session, the signal decrease can be
estimated and compensated before processing, minimizing
the detrimental effects on all further analyses.
|
4461.
![](MAGNA25.jpg) |
50 |
Correction of Off-resonance
Distortions in In-vivo Cardiac Diffusion Tensor Imaging ![](play.gif)
Jack Harmer1, Rachel W Chan2,
Christian T Stoeck3, Constantin V Deuster3,
David Atkinson2, and Sebastian Kozerke1,3
1Division of Imaging Sciences & Biomedical
Engineering, King's College London, London, United
Kingdom, 2Centre
for Medical Imaging, University College London, London,
Greater London, United Kingdom, 3Institute
for Biomedical Engineering, University and ETH Zurich,
Zurich, Switzerland
Advances in diffusion acquisition schemes employing
stimulated echo modes now allow diffusion tensor imaging
of the beating heart. However these pulse sequences
almost invariably use single shot EPI readout modules
that are extremely sensitive to magnetic field
inhomogeneities. We demonstrate the feasibility of
acquiring fully sampled single-shot in-vivo cardiac DTI
data at 3T, in order to maximise SNR, by employing
off-resonance correction as part of the reconstruction
process. We demonstrate that such correction can be used
to accurately reconstruct the correct geometry in areas
of severe geometric distortion and signal pileup, whilst
still allowing diffusion tensors to be reconstructed.
|
4462. |
51 |
Comparison of extended
Point Spread Function and Reverse Gradient Polarity
distortion corrections in quantification of DW EPI at UHF ![](play.gif)
Oleg Posnansky1, Myung-Ho In1, and
Oliver Speck1
1Department of Biomedical Magnetic Resonance,
Institute of Experimental Physics, Otto-von-Guericke
University, Magdeburg, Germany
In this study, we compare fractional anisotropy (FA)
maps and DT (diffusion tensor) fiber tracks built after
application of extended PSF, and Reverse Gradient
Polarity distortion correction methods. The results
demonstrate that the extended PSF method is very
efficient for the correction of distortions in both
DW-EPI data with opposite PE polarity, and thus it
unveils properly positioned and fully recovered fine
anatomical structures in the brain FA maps and fiber
tracks. Due to its high accuracy extended PSF provides
overwhelming correspondence between anatomy and
connectivity of the tissue.
|
4463. |
52 |
Higher order correction of
eddy current distortion in diffusion weighted echo planar
images. ![](play.gif)
Alan Seth Barnett1,2, Elizabeth Hutchinson1,2,
M Okan Irfanoglu1,2, and Carlo Pierpaoli1,2
1NICHD, NIH, Bethesda, Maryland, United
States, 2CNRM,
USUHS, Bethesda, MD, United States
Higher order correction is sometimes required for
adequate correction of eddy current induced distortion
of diffusion weighted MR Images. The work consists of a
description of the correction method and an example of a
data set that requires cubic correction.
|
4464. |
53 |
A method to combine multi
NEX diffusion weighted images using Homomorphic filter ![](play.gif)
Sangwoo Lee1, Mitsuhiro Bekku2,
Jeong Min Lee3, Jeong Hee Yoon3,
Yuji Iwadate4, and Hiroyuki Kabasawa4
1Global MR Applications and Workflow, GE
Healthcare, Seoul, Korea, 2MR
Engineering, GE Healthcare, Hino-shi, Tokyo, Japan, 3Seoul
National University Hospital, Seoul, Korea, 4Global
MR Applications and Workflow, Hino-shi, Tokyo, Japan
Tissue movements from respiration, cardiac, and
peristaltic motion during diffusion gradient can cause
signal loss, which often leads to local overestimation
of ADC map. To reduce motion induced signal loss,
maximum intensity projection, weighted averaging or
weighted multiplication methods have been proposed.
These post processing methods are simple and efficient;
however the final images cannot achieve pixel
intensities higher than acquired raw images. To overcome
such limitation, we propose a new image combining method
with homomorphic filtering (H-MSW) and show the
feasibility of the proposed via simulation and in vivo
experiment.
|
4465. |
54 |
Total Variation-Regularized
Compressed Sensing Reconstruction for Multi-shell Diffusion
Kurtosis Imaging ![](play.gif)
Jonathan I. Sperl1, Tim Sprenger1,2,
Ek T. Tan3, Vladimir Golkov1,4,
Marion I. Menzel1, Christopher J. Hardy3,
and Luca Marinelli3
1GE Global Research, Munich, BY, Germany, 2IMETUM,
Technical University Munich, Munich, BY, Germany, 3GE
Global Research, Niskayuna, NY, United States, 4Computer
Vision Group, Technical University Munich, Munich, BY,
Germany
In Diffusion Kurtosis Imaging (DKI) the data is sampled
in a series of concentric shells in the diffusion
encoding space (q-space). This work proposes to randomly
undersample this multi-shell data in q-space (i.e. to
acquire fewer data points) and to exploit the 1D Fourier
relation between single rays in q-space and in the
reciprocal propagator space in order to reconstruct the
missing points based on the principles of compressed
sensing using a non-cartesian total variation
regularization. The benefits of this approach in terms
of stability and accuracy of the kurtosis tensor
estimation are shown for a volunteer diffusion MR data
set using undersampling factors up to R=2.
|
4466. |
55 |
Model-based DTI
reconstruction with sparsity constraints on the diffusion
tensor ![](play.gif)
Florian Knoll1, Jos'e G Raya1,
Rafael O Halloran2, Steven Beate1,
Eric Sigmund1, Roland Bammer2,
Tobias Block1, Ricardo Otazo1, and
Daniel K Sodickson1
1Bernard & Irene Schwartz Center for
Biomedical Imaging, Department of Radiology, NYU School
of Medicine, New York, New York, United States,2Radiology,
Stanford University, Stanford, California, United States
DTI allows to obtain quantitative measurements of tissue
microstructure that no other technique can reveal. A
simple and well defined signal model exists for DTI,
which makes it an ideal candidate for model-based
methods. The goal of this study is to introduce a new
combination of compressed sensing and model based
reconstruction where the sparsifying transform is
evaluated directly in the domain of the diffusion
tensor. Experimental results for truly accelerated
in-vivo imaging are shown for both brain an MSK
applications which demonstrate excellent performance of
the model based approach.
|
4467. |
56 |
Low Rank SENSE: A Robust
Reconstruction Method for ms-EPI based high spatial
resolution DWI ![](play.gif)
Feng Huang1, Zhe Zhang2, Randy
Duensing1, Bida Zhang3, and Hua
Guo2
1Philips Healthcare, Gainesville, FL, United
States, 2Center
for Biomedical Imaging Research, Department of
Biomedical Engineering, School of Medicine, Tsinghua
University, Beijing, China, 3Philips
Research China, Beijing, China
Multi-shot EPI has been proposed for high spatial
resolution DWI. Due to inter-shot motion, there are
phase inconsistency among shots. Unlike the existing
reconstruction methods for ms-EPI, we treat this ms-EPI
as accelerated dyanmic imaging. Instead of correcting
the phase difference, we use the low-rank property of
the data set and parallel imaging to reconstruct the
images of each shot. Experiments demonstrate that the
proposed method can robustly reconstruct high quality
DWI with up to 8-shot data set acquired by an 8-channel
head coil.
|
4468. |
57 |
CSF contamination
contributes to apparent microstructural alterations in
amnestic Mild Cognitive Impairment ![](play.gif)
Rok Berlot1,2, Claudia Metzler-Baddeley3,
Derek K Jones3, and Michael J O'Sullivan1
1Department of Clinical Neuroscience,
Institute of Psychiatry, King's College London, London,
United Kingdom, 2Department
of Neurology, University Medical Centre Ljubljana,
Ljubljana, Slovenia, 3Cardiff
University Brain Research Imaging Centre (CUBRIC),
School of Psychology, and the Neuroscience and Mental
Health Research Institute, Cardiff University, Cardiff,
United Kingdom
Partial volume effects due to cerebrospinal-fluid
contamination (CSFC) lead to artefacts in diffusion MRI
studies in populations prone to atrophy. We explored the
influence of CSFC on apparent microstructural
differences in amnestic mild cognitive impairment (MCI).
A post-acquisition method of Free Water Elimination was
used to correct for CSFC. Comparisons between controls
and MCI were performed at several spatial levels in
uncorrected and corrected data. CSFC shifted the pattern
of involvement of individual temporal association
tracts. Tract-based spatial statistics were robust to
CSFC with notable localised exceptions. A proportion of
group difference in mean histogram metrics was driven by
CSFC.
|
4469. |
58 |
Parametric representation,
variability analysis and atlas construction of the mouse
myocardial fiber structure
Samer Sarfaraz Merchant1, Arnold David Gomez1,
and Edward Hsu2
1BioEngineering, University of Utah, Salt
Lake City, Utah, United States, 2University
of Utah, BioEngineering, Salt Lake City, Utah, United
States
Myofiber atlases have been constructed from cardiac DTI
datasets using voxel-based statistics, which is prone to
noise and omits obvious functional and structural
interconnectivities of the organ. In the current work,
parametric modeling and principal component analysis
were performed to characterize and investigate the
variability of myofiber structure in a group of 6 mouse
hearts. Results show that the hearts can be well
represented by a 16-term parametric function in prolate
spheroidal space, and majority of the heart-to-heart
variability exists concentrically in the transmural
dimension. These findings are valuable for design and
interpretation of DTI cardiac structural measurement and
modeling.
|
4470. |
59 |
Evaluation of Diffusion
Spectrum Imaging Reconstruction with Trained Dictionaries
use of 3T MR ![](play.gif)
Ping-Hong Yeh1, Namgyun Lee2, John
Morissette3, Arman A. Taheri3,
Li-Wei Kuo4, Fang-Cheng Yeh5,
Erick Jorge Canales- Rodríguez6, Wei Lui3,
John Ollinger3, Terrence Oakes3,
Mark L. Ettenhofer7, and Gerard Riedy3
1Henry Jackson Foundation for the Advancement
of Military Medicine, Bethesda, MD, United States, 2Korea
Basic Science Institute, Korea, 3National
Capital Neuroimaging Consortium, Bethesda, MD, United
States, 4National
Health Research Institutes, Taiwan, 5Carnegie
Mellon University, PA, United States, 6FIDMAG
Research Foundation, Germanes Hospitalaries and
CIBERSAM, Barcelona, Spain, 77Uniformed
Services University of the Health Sciences, MD, United
States
Recent work using Compressed Sensing (CS) reconstruction
shows promising in greatly reducing diffusion spectrum
imaging (DSI) scan time without jeopardizing critical
image information. We evaluate the performance of CS
reconstruction using dictionary-based training coupled
with the Focal Underdetermined System Solver (FOCUSS)
algorithm and L2 regularization on undersampled human
brain DSI data acquired by a clinical 3T MR scanner
within an acceptable time frame (< 20 minutes).
|
4471. |
60 |
Semi-Joint Reconstruction
for Diffusion MRI Denoising Imposing Similarity of Edges in
Similar Diffusion-Weighted Images ![](play.gif)
Vladimir Golkov1,2, Marion I. Menzel1,
Tim Sprenger1,3, Axel Haase3,
Daniel Cremers2, and Jonathan I. Sperl1
1Diagnostics & Biomedical Technologies -
Europe, GE Global Research, Garching n. Munich, Germany, 2Department
of Computer Science, Technische Universität München,
Garching n. Munich, Germany, 3Institute
of Medical Engineering, Technische Universität München,
Garching n. Munich, Germany
Recently, Joint Reconstruction has been proposed by
Haldar et al. for SNR enhancement of diffusion-weighted
images (DWIs), performing edge-preserving denoising by
imposing identical edge constraints to all DWIs. In this
work, we propose Semi-Joint Reconstruction to allow
individual edges for each DWI in order to account for
the fact that distinct DWIs can look quite dissimilarly,
whereas similar DWIs contain common edge structures.
Individual edge maps necessitate edge map denoising, for
which we use DWI similarity weightings, truncated
singular value decomposition of DWIs, and shearlet-based
edge detectors. Results are comparable to Joint
Reconstruction, but more stable to regularization
parameter choice.
|
4472. |
61 |
Direct Reconstruction of
the Average Diffusion Propagator with Simultaneous
Compressed-Sensing-Accelerated Diffusion Spectrum Imaging
and Image Denoising by Means of Total Generalized Variation
Regularization ![](play.gif)
Vladimir Golkov1,2, Marion I. Menzel1,
Tim Sprenger1,3, Mohamed Souiai2,
Axel Haase3, Daniel Cremers2, and
Jonathan I. Sperl1
1Diagnostics & Biomedical Technologies -
Europe, GE Global Research, Garching n. Munich, Germany, 2Department
of Computer Science, Technische Universität München,
Garching n. Munich, Germany, 3Institute
of Medical Engineering, Technische Universität München,
Garching n. Munich, Germany
Reconstruction of diffusion-weighted images (DWIs) in
diffusion MRI is usually done independently for each DWI,
without exploiting structural correlations between the
DWIs. In this work, we propose direct reconstruction of
the average diffusion propagator (directly from k-space
data), taking advantage of the DWIs being linked
together via their Fourier relationship with the average
propagator space, while regularization using
five-dimensional total generalized variation (TGV) along
both image space and diffusion space is applied. The
results demonstrate the ability of the method to
reconstruct q-space-undersampled data in a compressed
sensing framework, simultaneously denoising the data.
|
4473. |
62 |
A Novel Post-processing
Procedure to Sharpen the ODFs of Different HARDI Datasets by
Using Super-CSD
Shiou-Ping Lee1, Chung-Ming Chen2,
Li-Chun Hsieh1, Wing-Keung Cheung1,
Yu-Chiang Chen1, and Ming-Chung Chou3
1Department of Medical imaging, Far Eastern
Memorial hospital, Banqiao, New Taipei city, Taiwan, 2Insitute
of Biomedical Engineering, National Taiwan University,
Taipei, Taiwan, 3Department
of Medical Imaging and Radiological Sciences, Kaohsiung
Medical University, Kaohsiung, Taiwan
Recently, there were a variety of algorithms proposed to
reconstruct orientation distribution function based on
high angular resolution diffusion imaging data in order
to resolve multiple fiber orientations. However, it was
found that some fiber orientations were likely lost when
fibers intersected at a small angle. A previous study
performed the super resolved - constrained spherical
deconvolution to resolve multiple fiber orientations
crossing at a smaller angle, but the method was only
suitable for diffusion-weighted datasets acquired in a
spherical coordinate, such as q-ball imaging. Other
HARDI datasets, such as diffusion spectrum imaging,
acquired in a Cartestian coordinate whose fiber
orientation distribution could not be obtained by using
super-CSD. Hence, the purpose of this study is to
propose a post-processing procedure which is suitable
for sharpening ODFs of different HARDI datasets and
resolving multiple fiber orientations by using super-CSD.
|
4474. |
63 |
3D locally dependent
regularization of the diffusion tensor using ICA and TGV ![](play.gif)
Gernot Reishofer1, Kristian Bredies2,
Karl Koschutnig3, Margit Jehna4,
Christian Langkammer5, David Porter6,
and Hannes Deutschmann4
1Radiology, Medical University of Graz, Graz,
Styria, Austria, 2Institute
for Mathematics and Scientific Computing, Universtiy of
Graz, Austria,3Psychology, Universtiy of
Graz, Austria, 4Neuroradiology,
Medical University of Graz, Austria, 5Neurology,
Medical University of Graz, Austria, 6Siemens
AG, Healthcare Sector, MR R&D, Germany
It has been shown recently, that spatially dependent
regularization of the diffusion tensor applied on
readout-segmented echo planar imaging (rs-EPI) with 2D
navigator-based reacquisition significantly improves
fractional anisotropy (FA) maps and tractography. In
this work we propose a novel approach for automatic
regularizing the entire diffusion tensor utilizing a
three dimensional implementation of total generalized
variation (TGV). The evaluation of the noise
distribution of the diffusion tensor by means of ICA
allows for an automatic update of the regularization
parameter making the proposed algorithm
user-independent. Furthermore the incorporation of the
locally varying noise distribution allows for a
spatially dependent regularization.
|
4475. |
64 |
Human Brain Intravoxel
Incoherent Motion (IVIM) : Optimized set-up for clinical
investigation ![](play.gif)
Alberto Ciarmatori1,2, Elisa Cenacchi1,
Tiziana Costi1, and Luca Nocetti1
1Medical Physics Department, University
Hospital "Policlinico", Modena, Italy, 2Medical
Physics School, University "Alma Mater Studiorum",
Bologna, Italy
This study focused on separation of vascular and
non-vascular component of DWI signal decay. Brain scans
were performed using a 3T whole body MR on six healthy
volunteers. DWIs with multiple b-values
(0-5-10-20-30-40-50-75-100-150-200-300-500-1000 s/mm2)
were obtained. Datas were fitted with a biexponential
function with Diffusion Coefficient and Perfusion
Fraction obtained from high-b (>250 s/mm2)
monoexponential fit. A temporal optimized (6 min)
sequence was found . Significative differences were
observed D and standard ADC as well as between gray
matter and white matter diffusion parameters. In
particular D* of gray matter resulted significantly
greater than in white matter.
|
4476. |
65 |
Combining Multi-Centre
Conventional and Diffusion MR Texture for the
Characterisation of Childhood Brain Tumours ![](play.gif)
S. Tantisatirapong1, N. P. Davies1,2,
D. Rodriguez3, L. Abernethy4, D.
P. Auer3,5, C. A. Clark6,7, R.
Grundy3,5, T. Jaspan5, D. Hargrave7,
L. MacPherson2, M. O. Leach8, G.
S. Payne8, B. L. Pizer4, S. Bailey9,
A. C. Peet1,10, and T. N. Arvanitis10,11
1University of Birmingham, Edgbaston,
Birmingham, United Kingdom, 2University
Hospitals Birmingham NHS Foundation Trust, Birmingham,
United Kingdom, 3University
of Nottingham, Nottingham, United Kingdom, 4Alder
Hey Children’s NHS Foundation Trust, Liverpool, United
Kingdom, 5University
Hospital Nottingham, Nottingham, United Kingdom, 6University
College London, London, United Kingdom, 7Great
Ormond Street Hospital, London, United Kingdom, 8The
Institute of Cancer Research and Royal Marsden Hospital,
Sutton, United Kingdom, 9Northern
Institute for Cancer Research, Newcastle University,
Newcastle upon Tyne, United Kingdom, 10Birmingham
Children’s Hospital NHS Foundation Trust, Birmingham,
United Kingdom, 11Institute
of Digital Healthcare, WMG, University of Warwick,
Coventry, United Kingdom
This paper presents integration of multimodal MR image
based texture analysis which take advantage of
complementary information derived from structural and
diffusion MR images. A supervised machine learning
approach is used to achieve image analysis based on
textural features from individual image types of T2,
T1-post contrast and ADC, as well their combination, in
order to characterize the multicenter dataset of the
most common pediatric brain tumors; medulloblastomas
(MB), pilocytic astrocytomas (PA), and ependymomas (EP).
|
4477. |
66 |
Combined Segmentation and
Sequential Registration Method for Artifact Removal in ADC
maps in Liver ![](play.gif)
Harini Veeraraghavan1, Joseph O. Deasy1,
and Richard K.G. Do1
1Memorial Sloan Kettering Cancer Center, New
York, New York, United States
Bulk motion artifacts adversely impact the reproducible
measurement of ADCs in the liver. We present a combined
segmentation and sequential registration to align multi
b-valued DWI images that removes artifacts and computes
repeatable ADC mappings. Our approach uses the automatic
volumetric segmentation of structures of interest
(tumor) with a sequential registration such that the
artifacts are most removed around those structures.
Evaluation over multiple trials with introduced motion
on 14 patients show that our approach results in least
artifacts and lowest standard deviation of mean ADC in
the tumors compared to either no registration or
simultaneous affine registration.
|
4478. |
67 |
Segmentation of renal
structures in distortion corrected diffusion-weighted
echo-planar images based on anatomical FSE and GRE images ![](play.gif)
Susanne Will1, Petros Martirosian1,
Christina Schraml1,2, Bernd Kardatzki3,
Michael Erb3, Günter Steidle1, and
Fritz Schick1
1Department of Diagnostic and Interventional
Radiology, University of Tuebingen, Tuebingen, Germany, 2Section
on Experimental Radiology, University of Tuebingen,
Germany, 3Department
of Biomedical Magnetic Resonance, University of
Tuebingen, Germany
Classification of anatomical renal structures in
diffusion-weighted echo-planar images may be difficult
to perform. For this reason a simple transfer of
segmented areas from high-resolution FSE/GRE images with
suitable visualization of the anatomy to DTI images
would be helpful but is hampered by geometric
distortions. The purpose of this study was to assess the
feasibility of renal segmentation and their internal
structures in distortion corrected DTI images. Six
volunteers were examined at 3T. It was found that DTI
values can be accurately determined in specific areas of
distortion corrected images by manual renal segmentation
in corresponding high-resolution anatomical images.
|
4479. |
68 |
Comparison of the accuracy
between manual and computerized anatomical delineation
techniques in ex-vivo diffusion tensor imaging of the mouse
brain. ![](play.gif)
Hedok Lee1,2, Joe Cavallo1, Vivek
Goyal1, Sagar Dhandia1, Michael
Cutrone1, Elyssa Chen1, Tian Fang1,
Helene Benveniste1,2, and Thomas Floyd1,2
1Anesthesiology, State University of New York
at Stony Brook, Stony Brook, New York, United States, 2Radiology,
State University of New York at Stony Brook, Stony
Brook, New York, United States
In this study we compared manual and semi-automated
computerized anatomical delineation techniques in
ex-vivo diffusion tensor imaging of the mouse brain. The
accuracy of both FAs and anatomical volumes in the
computerized technique was comparable or just below the
discrepancies caused by subjective bias between the two
raters. We conclude that the computerized method is
effective and time efficient method in analyzing FA and
anatomical volumes.
|
4480. |
69 |
A GPU-based parallel
computing framework for accelerating graph theoretical
analyses ![](play.gif)
Tsang-Chu Yu1, Yi-Ping Chao1,
Li-Wei Kuo2, Chung-Chih Lin1,
Shih-Yen Lin2,3, Hengtai Jan2,
Claudia Metzler-Baddeley4, and Derek Jones4
1Department of Computer Science and
Information Engineering, Chang Gung University, Taoyuan,
Taiwan, 2Institute
of Biomedical Engineering and Nanomedicine, National
Health Research Institutes, Miaoli, Taiwan, 3Department
of Computer Science, National Chiao Tung University,
Hsinchu, Taiwan,4School of Psychology,
Cardiff University, Cardiff, United Kingdom
The main purpose of this study is to develop a graphics
processing unit based framework for brain network
analysis that permit networks comprising much larger
numbers of nodes and provide the acceleration for
processing. From the results, our implementation for the
calculation of all pair shortest paths could reduce half
of time with brain connectivity toolbox (BCT) and 638x
speedup with Gretna in simulation random network with
larger number of nodes (>8k). Moreover, our algorithm
also shows better performance in human brain data with
1.37x and 21x speedup in comparison with BCT and Gretna
respectively.
|
4481. |
70 |
A New Algorithm to Estimate
the Mean of A Group of Tract Bundles ![](play.gif)
Hsu Yung-Chin1 and
Tseng Isaac Wen-Yih1,2
1Center for Optoelectronic Medicine, College
of Medicine, National Taiwan University, Taipei, Taipei,
Taiwan, 2Graduate
Institute of Brain and Mind Sciences, College of
Medicine, National Taiwan University, Taipei, Taiwan
In the study, we propose a new algorithm to iteratively
estimate the mean shape of a group of tract bundles. The
basic idea of our algorithm is: performing registration
on tract bundles and taking the average on orientation
maps. The conversion from orientation maps to tract
bundles is achieved via fiber-tracking algorithms, and
the reverse way is via modeling the tract bundles as
currents. The algorithm is demonstrated on ten right
cingulum bundles, and the results show that this method
could properly estimate the mean cingulum bundle. This
method has the potential to facilitate computational
anatomy of the brain.
|
4482. |
71 |
Moderate protein content
does not influence on DWI-thermometry:
Temperature-controlled Artificial CSF phantom study ![](play.gif)
Koji Sakai1, Ryusuke Nakai1, Kei
Yamada2, Jun Tazoe2, Kentaro
Aakazawa2, and Naozo Sugimoto1
1Kyoto University, Kyoto, Kyoto, Japan, 2Kyoto
Prefectural University of Medicine, Kyoto, Japan
Among MR thermometry, the most clinically applicable may
be the post processing of diffusion-weighted images (DWI).
However, this DWI-based method might be influenced by
the composition of CSF, which can strongly affect its
viscosity and diffusivity. The purpose of this study was
to investigate the influence of protein content on DWI
thermometry by using temperature-controlled artificial
CSF (ACSF). The results of DWI thermometry were not
influenced by the protein content in the range of 0.0 to
8.01 mg/ml (approximately 40 times protein content of
normal adult) at near body temperature.
|
4483. |
72 |
Reliable Analysis of
Tract-specific Multiparametric MR Data via Automated
Isolation of Nigro-Striatal Tract ![](play.gif)
Ryan Hutten1, Nisa Desai1,
Demetrius Maraganore2,3, Robert R. Edelman1,4,
and Ying Wu1,5
1Radiology, Northshore University Health
System, Evanston, IL, United States, 2Neurology,
Northshore University Health System, IL, United States,3Neurology,
University of Chicago, IL, United States, 4Radiology,
Northwestern University Feinberg School of Medicine,
Chicago, IL, United States,5Radiology,
University of Chicago, Chicago, IL, United States
Automated tract based diffusion tensor imaging (DTI) and
magnetization transfer ratio (MTR) of the nigro-striatal
tract (NST) represents a high innovative neuroimaging
approach in Parkinson’s disease. The NST is a major
dopamine pathway that is critically involved in
Parkinson’s Disease (PD) diagnosis and treatment
modulation. The development of the automated NST
overcomes the challenges associated with segmenting SN,
and the necessity of manual seed regions for
tractography. We demonstrate considerably improved
reliability that eliminates operator-induced error that
will benefit future longitudinal studies of Parkinson's
disease.
|
|
|
|
ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Diffusion Models
Wednesday 14 May 2014
Exhibition Hall |
14:30 - 15:30 |
|
|
|
Computer # |
|
4484. |
1 |
New Insights into Rabbit
Brain Development with Generalized Q-Sampling MRI ![](play.gif)
Fang-Yu Nien1, Seong Yong Lim1,
Yu-Han Hong1, Ya-Han Chang1, and
Jun-Cheng Weng1,2
1School of Medical Imaging and Radiological
Sciences, Chung Shan Medical University, Taichung,
Taiwan, 2Department
of Medical Imaging, Chung Shan Medical University
Hospital, Taichung, Taiwan
Characterizing complex anatomy at different stages of
brain development not only aids in understanding this
highly ordered process but also provides clues to detect
abnormalities caused by genetic or environmental
factors. Diffusion MRI allows for the in vivo
delineation of white matter tracts in the brain in a
manner that is individualized to the particular
neuroanatomy of each subject. Diffusion anisotropy and
diffusivity change in some brain regions with
demyelinating disease and also with neural development.
Previously we used diffusion tensor imaging (DTI) to
detect the changes of white matter tracts of rabbit
during brain development. However, DTI suffers from
resolving the complicated neural structure, i.e. fiber
crossing, which is observed frequently during mature
period. Therefore the goal of this study was to
characterize the changes of quantitative diffusion
indices in the developing rabbit brains using
generalized q-sampling imaging (GQI).
|
4485. |
2 |
Transforming grids to
shells and vice versa: an evaluation of interpolation
methods in diffusion MRI q- and b-space ![](play.gif)
Chantal M.W. Tax1, Sjoerd B. Vos1,
Max A. Viergever1, Martijn Froeling2,
and Alexander Leemans1
1Image Sciences Institute, University Medical
Center Utrecht, Utrecht, Utrecht, Netherlands, 2Department
of Radiology, University Medical Center Utrecht,
Utrecht, Utrecht, Netherlands
Interpolation in q- or b-space can be used to convert
between different sampling patterns (e.g. from multi
shell to grid as in hybrid diffusion imaging) to be able
to compare between diffusion MRI reconstruction methods,
or to detect and correct for artifacts, amongst others.
In this work we perform a comparison between different
interpolation methods (i.e. nearest neighbor, linear,
cubic and model based) in q- and b-space, on simulated
data.
|
4486. |
3 |
Two-component Low Q-space
Diffusion MRI in Evaluation of Spinal Cord in Patients with
Cervical Spondylosis in Vivo: a Feasibility Study
-permission withheld
Masaaki Hori1, Koji Kamagata1,
Mariko Yoshida1, Nozomi Hamasaki2,
Shuji Sato2, Kouhei Kamiya1,3,
Yuriko Suzuki4, Michimasa Suzuki1,
and Shigeki Aoki1
1Radiology, Juntendo University School of
Medicine, Tokyo, Japan, 2Juntendo
University Hospital, Tokyo, Japan, 3Radiology,
The University of Tokyo, Tokyo, Japan, 4Philips
Electronics Japan, Ltd, Tokyo, Japan
We investigate two-component low q-space diffusion MRI
in evaluation of microstructural changes in the spinal
cord in patients with cervical spondylosis in vivo, as a
feasibility study. Five patients were enrolled in this
study. There were significant differences in root mean
square displacement of water molecules in extra- and
intra- cellular spaces between compressed and
uncompressed area in the spinal cords. More studies of
the imaging pathological correlation and improvement of
image quality are needed; this technique has the
potential to provide new information in patients with
spinal cord in vivo.
|
4487. |
4 |
Rotation-invariant measures
for population study in HARDI
Emmanuel Caruyer1 and
Ragini Verma1
1Section of Biomedical Image Analysis,
Department of Radiology, University of Pennsylvania,
Philadelphia, PA, United States
We present a novel family of rotational-invariant
measures for High Angular Resolution Diffusion Imaging1
(HARDI) data. This research is motivated by need for the
developing new biomarkers and thereby facilitating
population-based studies in HARDI. From a spherical
harmonics (SH) representation of the angular information
in diffusion MRI, we derive 12 rotational-invariant
measures computed as homogeneous polynomials of the SH
coefficients. These measures are expected to be
sensitive to subtle changes in white matter structure,
not captured by FA or GFA. The large number of measures
will be used to create population classifiers, paving
the way for pathology-specific biomarkers.
|
4488. |
5 |
Optimization of a Fast
Diffusion Estimation Two-Compartment Model for Diffusion
Tensor Imaging ![](play.gif)
Andrew R. Hoy1,2, Chen Guan Koay1,
Steven R. Kecskemeti2,3, and Andrew L.
Alexander1,2
1Medical Physics, University of Wisconsin,
Madison, Wisconsin, United States, 2Waisman
Laboratory for Brain Imaging and Behavior, Madison,
Wisconsin, United States, 3Radiology,
University of Wisconsin, Madison, Wisconsin, United
States
Diffusion tensor imaging yields information about tissue
microstructure. However, when a single voxel contains
tissue and free water, DTI is not appropriate. A
two-tensor fast diffusion estimation model has been
proposed to correct this shortcoming. This model was
implemented in a novel manner, and the acquisition
parameters optimized through Monte Carlo simulations.
The optimal acquisition with 68 diffusion-weighted
encoded images had three diffusion-weighted shells
(b-value in s/mm2 x number of directions) of 200x12,
650x40, 1500x12. This was confirmed in vivo. The model
is useful for tissues adjacent to CSF and removing
artifacts from CSF blurring and ghosting.
|
4489. |
6 |
High Resolution Diffusion
Imaging of the Brain Stem for Non-Gaussian Diffusion
Analysis at High b-Values ![](play.gif)
Yi Sui1,2, Frederick C. Damen1,3,
and Xiaohong Joe Zhou1,4
1Center for MR Research, University of
Illinois at Chicago, Chicago, Illinois, United States, 2Department
of Bioengineering, University of Illinois at Chicago,
Chicago, Illinois, United States, 3Department
of Radiology, University of Illinois Hospital & Health
Sciences System, Chicago, Illinois, United States,4Departments
of Radiology, Neurosurgery and Bioengineering,
University of Illinois Hospital & Health Sciences
System, Chicago, Illinois, United States
An integrated high-resolution, multi-b-value diffusion
acquisition approach has been developed with reduced FOV
and phase-sensitive signal averaging. Using this
approach, distortion-free brain stem diffusion images
with an in-plane resolution of ~0.6×0.6 mm2 have
been obtained at b-values up to 4000 s/mm2 and
successfully fitted to a non-Gaussian diffusion model
(Fractional Order Calculus model). This study
demonstrates the potential for extending the
applications of high b-value non-Gaussian diffusion
models to fine brain structures.
|
4490. |
7 |
Experimentally estimated
non-Gaussian water diffusion at a large range of b-values ![](play.gif)
Louise Munk Rydtoft1, Brian Hansen1,
Mikkel Bo Hansen1, and Sune Nørhøj Jespersen1,2
1CFIN / MindLab, Aarhus university, Aarhus,
Denmark, 2Department
of physics and astronomy, Aarhus University, Denmark
Conventionally DTI is deemed accurate for b-values below
1000 s/mm2 and
DKI for b-values below 2000 s/mm2. By
analysing DKI and DTI fits on data from a human
volunteer and perfusion fixated rat, we show the DKI
model is a better fit for a linearly increasing ratio of
voxels, independent on tissue type. Up to one-third of
voxels are better fitted by DKI when maximum b-value is
1000 s/mm2. DKI is a convincing alternative
to DTI, even at smaller b-values that has generally been
accepted. Also, we show that the fixation process indeed
restricts diffusion; this is disputed in the literature.
|
4491. |
8 |
Analysis of the cumulant
expansion terms of the diffusion-weighted MRI signal in the
human brain
-permission withheld
Ezequiel Farrher1, Farida Grinberg1,2,
Ivan I. Maximov1, and N. Jon Shah1,2
1INM - 4, Research Centre Jülich GmbH,
Jülich, Germany, 2Department
of Neurology, RWTH Aachen University, Aachen, Germany
Diffusion kurtosis imaging has become an important
extension to diffusion tensor imaging in the
quantification of non-Gaussian diffusion by means of
magnetic resonance imaging. However, there is still no
general consensus on the optimal range of b-values for
data analysis. In this work we perform an investigation
on the dependence of the cumulant expansion terms of the
diffusion-weighted MRI signal on the fitting b-value
range. The present analysis gives important insights
into the validity of the fitting b-value range in DKI
analysis.
|
4492. |
9 |
Improving fiber orientation
estimation in constrained spherical deconvolution under
non-white matter partial volume effects ![](play.gif)
Timo Roine1, Ben Jeurissen1,
Wilfried Philips2, Alexander Leemans3,
and Jan Sijbers1
1iMinds-Vision Lab, University of Antwerp,
Antwerp, Flanders, Belgium, 2Department
of Telecommunications and Information Processing,
University of Ghent, Ghent, Flanders, Belgium, 3Image
Sciences Institute, University Medical Center Utrecht,
Utrecht, Netherlands
Diffusion-weighted magnetic resonance imaging is prone
to large partial volume effects (PVEs) due to its large
voxel size. In this work, we studied the PVEs with
non-white matter (WM) tissue on estimation of the fiber
orientation distribution function (fODF) with
constrained spherical deconvolution (CSD). We found a
loss of precision in the detected fiber orientations and
an emergence of a high number of false orientations in
the fODF. The effects were most significant with gray
matter (GM) partial volume. We propose a modification to
CSD to further improve the estimation of the fODF
especially near the WM-GM interface.
|
4493. |
10 |
A Combined Analysis of the
Non-Gaussian Diffusion Methods in Monte Carlo Simulations,
Anisotropic Fibre Phantoms, and in in vivo Human Brain
Tissues ![](play.gif)
Farida A Grinberg1, Ezequiel Farrher1,
Ivan I Maximov1, and N. Jon Shah1,2
1INM-4, Forschungszentrum Juelich, Juelich,
Germany, 2Department
of Neurology, RWTH Aachen University, Aachen, Germany
This work provides a comparative analysis of the four
non-monoexponential functions in fitting the diffusion
response in a) the Monte Carlo diffusion simulations in
a set of cylindrical objects, b) synthetic fibre
phantoms with parallel and crossing fibres, and c) in
vivo human brain tissue. All functions including the
diffusion kurtosis, stretched-exponential, the
lognormal- and gamma-distribution functions were shown
to provide complimentary information and different
contrasts in parameter maps.
|
4494. |
11 |
Altered Global and Regional
Brain Mean Kurtosis in Recently-Diagnosed Patients with
Obstructive Sleep Apnea
-permission withheld
Rajesh Kumar1, Santosh K Yadav1,
Jennifer A Ogren2, Mary A Woo2,
Daniel W Kang3, Paul M Macey2,
Frisca L Yan-Go4, and Ronald M Harper5
1Anesthesiology, University of California at
Los Angeles, Los Angeles, CA, United States, 2UCLA
School of Nursing, University of California at Los
Angeles, Los Angeles, CA, United States, 3Medicine,
University of California at Los Angeles, Los Angeles,
CA, United States, 4Neurology,
University of California at Los Angeles, Los Angeles,
CA, United States, 5Neurobiology,
University of California at Los Angeles, Los Angeles,
CA, United States
Obstructive sleep apnea (OSA) patients show structural
injury and functional deficits in multiple brain areas,
based on various MRI techniques, in sites that regulate
autonomic, motor, cognitive, and mood functions,
deficient in the condition. However, the nature of
tissue injury remains unclear. We examined global and
regional mean kurtosis values in newly-diagnosed,
treatment-naive OSA patients, and found increased global
values in critical autonomic, cognitive, motor, and
respiratory control sites, including the insular
cortices, cerebellum, and basal-ganglia. The
pathological mechanisms contributing to tissue injury
likely include hypoxemia-induced processes, leading to
acute tissue changes in OSA.
|
4495. |
12 |
Demonstration of fast
diffusion kurtosis MRI for imaging acute ischemic stroke
diffusion/kurtosis lesion mismatch
-permission withheld
Phillip Zhe Sun1, Yu Wang1,2,
Emiri Mandeville3, Eng H Lo3, and
Xunming Ji2
1Radiology, Martinos Center for Biomedical
Imaging, Charlestown, MA, United States, 2Cerebrovascular
Diseases Research Institute, Xuanwu Hospital of Capital
Medical University, Beijing, China, 3Department
of Radiology and Neurology, Neuroprotection Research
Laboratory, MA, United States
Diffusion kurtosis MRI (DKI) is a complementary index to
stratify heterogeneous DWI deficit. However, DKI
acquisition time is relatively long. Here, we tested a
fast DKI approach, recently proposed by Hansen et al.,
using a rodent model of acute stroke. We found
significant correlation, per pixel, between the
diffusion and kurtosis coefficients measured using the
standard and fast DKI protocols. We further demonstrated
that diffusion and kurtosis lesion sizes defined using
the fast and conventional DKI methods were in good
agreement. Moreover, we showed that kurtosis lesion size
was significantly smaller than that of diffusion lesions
(72±16%, P<0.01, Paired-t test).
|
4496. |
13 |
Diffusional Kurtosis
Imaging of White Matter and Gray Matter Lesions in Multiple
Sclerosis: Combined Use with Double Inversion Recovery ![](play.gif)
Mariko Yoshida1, Masaaki Hori1,
Kazumasa Yokoyama2, Nozomi Hamasaki1,
Michimasa Suzuki1, Koji Kamagata1,
Kohei Kamiya1, Shigeki Aoki1,
Yoshitaka Masutani3, and Nobutaka Hattori2
1Department of Radiology, Juntendo University
School of Medicine, Bunkyo, Tokyo, Japan, 2Department
of Neurology, Juntendo University School of Medicine,
Tokyo, Japan, 3Division
of Radiology and Biomedical Engineering, Graduate School
of Medicine, The University of Tokyo, Tokyo, Japan
The purpose of this study is to evaluate diffusional
changes of the WM and GM including plaques, periplaque
WM (PWM), periplaque GM (PGM), NAWM, and NAGM in MS by
using a new method\DKI with double inversion recovery
(DIR) to segment GM. The participants were 7 MS patients
with GM plaques. DKI with DIR detected abnormalities in
WM and GM with high sensitivity and can provide
additional information on changes of WM and GM in MS. In
contrast to WM plaques, there may be little change in
the GM substance around GM plaques. MK may be a more
sensitive biomarker of tissue damage in MS patients.
|
4497. |
14 |
Comparison of Fitting
Methods and b value Sampling Strategies for Intravoxel
Incoherent Motion (IVIM) in Breast Cancer ![](play.gif)
Gene Young Cho1, Jeff L Zhang2,
Linda Moy1,3, Steven Baete1,
Melanie Moccaldi3, Sungheon Kim1,
Daniel K Sodickson1, and Eric E Sigmund1
1Radiology - Bernard and Irene Schwartz
Center for Biomedical Imaging, New York University
School of Medicine, New York, Select, United States,2Radiology,
University of Utah, Salt Lake City, UT, United States, 3Radiology,
New York University Cancer Institute, New York, NY,
United States
The selection of diffusion gradients for diffusion
weighted imaging (DWI) is important for protocol
optimization. It has been shown that different ranges of
gradients sensitize the signal to different components
of diffusion. Additionally, quantification of DWI data
with the biexponential IVIM fitting model can be
numerically nontrivial. In this study, we employ an
optimized b value selection for biexponential IVIM
analysis of breast lesions to increase measurement
precision. Eventually, optimization may lead to
increasing diagnostic differentiation between cancerous
subtypes and potentially allow more careful monitoring
of response to treatment.
|
4498. |
15 |
Effects of computation
methods, median filtering and Rician noise removal on
diffusional kurtosis and tensor imaging metrics in vivo ![](play.gif)
Masaaki Hori1,2, Yoshitaka Masutani3,
Ryuji Nojiri2, Katsutoshi Murata4,
Koji Kamagata1, Mariko Yoshida1,
Michimasa Suzuki1, and Shigeki Aoki1
1Radiology, Juntendo University School of
Medicine, Tokyo, Japan, 2Tokyo
Medical Clinic, Tokyo, Japan, 3The
University of Tokyo, Tokyo, Japan, 4Siemens
Japan K.K., Tokyo, Japan
The purpose of this exhibit is to characterize,
particularly for clinical use, the effects of
computation methods, median filtering and Rician noise
removal on diffusion tensor imaging (DTI) and
diffusional kurtosis imaging (DKI) metrics in normal
white matter and brain tumors. Median filtering is an
important factor that affects quantitative diffusion
metrics; for example, it changes fractional anisotropy
(FA) values by 10%. Differences of computing methods and
Rician noise removal appear to be less influential in
changing diffusion metrics. Selection of post-processing
methods should be clarified in research and clinical
use.
|
4499. |
16 |
Temporal change of bloody
fluid with apparent diffusion coefficient and T1-/
T2-relaxation time in a phantom study.
-permission withheld
Tomohiro Namimoto1, Kosuke Morita1,
Yuuki Kizaki1, Toshinori Hirai1,
Makoto Gotoh2, Yukimi Waki2, Ryo
Itatani1, and Yasuyuki Yamashita1
1Diagnostic Radiology, Kumamoto University,
Kumamoto, Kumamoto, Japan, 2Kumamoto
University Hospital, Kumamoto, Japan
We compared apparent diffusion coefficients (ADCs) with
T1-/T2-relaxation time in a phantom study. Blood
phantoms were gradually diluted with saline. MR
measurements were performed with T1-/T2-calculations and
ADCs from 0.2 hour to 7 days. T1-relaxation time
cumulatively increased and subsequently plateaued.
T2-relaxation time increased, and then decreased. ADC
slightly decreased during whole times. T1-relaxation
time and ADC was almost proportional decreased as blood
concentration decreased; T2-relaxation time was almost
inversely proportional decreased. Temporary change of
ADCin bloody fluid was poorly correlated with that of
T1-/T2-relaxation time. ADC is almost linearly dependent
on blood concentration and almost independent of
T1-/T2-relaxation times.
|
4500. |
17 |
Computing ADC for higher b-value
using log-linear relationship between ADC and b-value ![](play.gif)
Prativa Sahoo1, Rakesh Kumar Gupta2,
Indrajit Saha1, Bhaswati Roy2, Ram
Krishna Singh Rathore3, and Divya Rathore4
1Philips Healthcare, Philips India Ltd,
Gurgaon, Haryana, India, 2Radiology
and Imaging, Fortis Memorial Research Institute, Gurgaon,
Haryana, India,3Mathematics and Statistics,
Indian Institute of Technology Kanpur, Kanpur, UP,
India, 4ADISL
India, Kanpur, UP, India
Diffusion weighted imaging (DWI) is a very sensitive
imaging sequence for detecting various tissue
abnormalities in brain. In clinical practice, b-values
of 1000 sec/mm2 or less are commonly used; however it
has been reported that use of higher b-values improves
disease visualization and detection1. DWI imaging with
higher b-values is challenging because it suffers with
low signal to noise ratio (SNR), distortion along with
longer scan time. To overcome these difficulties
computed DWI technique has been proposed by many
researchers 2. Computed DWI technique is a mathematical
technique, which generates images of higher b-values by
using at least two different lower b value (b ≤ 1000)
images. Here we report that we have observed ADC depends
on b-values, on contrary to the previous assumption
where it was considered constant for all b-values and
computation of ADC corresponding to higher b-values was
not possible. The aim of this study was to find the
relationship between ADC and b-values for quantification
of ADC corresponding to higher b-values using lower
b-values with computed DWI technique.
|
4501. |
18 |
DTI fibre tracking: beyond
the main eigenvector ![](play.gif)
Ivan I. Maximov1, Anton Minnekhanov1,2,
Ezequiel Farrher1, Farida Grinberg1,
and N. Jon Shah1,3
1INM-4, Forschungszentrum Juelich, Juelich,
Germany, 2Department
of Physics, Moscow State University, Moscow, Russian
Federation, 3Department
of Neurology, RWTH Aachen University, Aachen, Germany
Diffusion tensor imaging is a well-known and
well-established imaging technique. It allows one to
easily visualize the neuronal tissue architecture by
using the eigenvector linked to the largest eigenvalue
of the diffusion tensor. However, the diffusion tensor
eigenvectors form a complete orthonormal basis in space
and contain additional information. We hypothesize here
that all three eigenvectors in the neuronal bundles can
generate a structure similar to a crystal lattice and
keep this configuration along the bundle with high
anisotropy. Thus, vector fields based on secondary
and/or tertiary eigenvectors could improve the
segmentation/reconstruction of fibre tracts and provide
additional information on white matter organisation.
|
4502. |
19 |
Diffusion Tensor Imaging of
Rat Brains Following Long-term Passive Acoustic Exposure at
Moderate Sound Pressure Level ![](play.gif)
Condon Lau1, Sherwin Abdoli2, Leon
C Ho3,4, Jevin W Zhang3,4, and Ed
X Wu3,4
1Division of Biomedical Engineering, HKUST,
Kowloon, Hong Kong, 2Keck
School of Medicine, University of Southern California,
CA, United States,3Department of Electrical
and Electronic Engineering, The University of Hong Kong,
Hong Kong, Hong Kong, 4Laboratory
of Biomedical Imaging and Signal Processing, The
University of Hong Kong, Hong Kong, Hong Kong
Diffusion tensor imaging was used to observe changes in
the brain structure of rats (n=16) following two months
of continuous and passive acoustic exposure at moderate
sound pressure level. Voxel-based statistics (VBS)
revealed greater fractional anisotropy of the pyramidal
tract, tectospinal tract, intertwined trigeminothalamic
tract and medial lemniscus of the exposed rats than of
the control rats. ROIs were drawn for the structures
indicated and applied to the fractional anisotropy and
mean diffusivity maps. ROI analysis confirmed that in
the structures indicated by VBS, fractional anisotropy
was higher and mean diffusivity was lower in exposed
rats than in normal rats.
|
4503. |
20 |
Development of a
hindered-diffusion-dominant DTI phantom made of polyethylene
fibers: Comparison with a restricted-diffusion phantom. ![](play.gif)
Atsushi Tachibana1, Takayuki Obata1,
Yasuhiko Tachibana1, Hiroshi Kawaguchi2,
Jeff Kershaw2, Ichio Aoki2,
Hiroshi Ito2, and Hiroshi Tsuji1
1Research Center for Charged Particle
Therapy, National Institute of Radiological Sciences,
Chiba-shi, Chiba, Japan, 2Molecular
Imaging Center, National Institute of Radiological
Sciences, Chiba-shi, Chiba, Japan
This study investigates the diffusion characteristics of
our newly developed DTI phantom made of bundled
polyethylene fibers (Dyneema (Dy)), in comparison to a
conventionally used glass made phantom with micro
capillaries (capillary plates (CP)). Dy was less
sensitive to diffusion time, implying that the water
diffusion is hindered rather than restricted. Dy also
had b-value dependent signal attenuation more similar to
that in vivo tissue, and was much less expensive than
CP. These suggest that Dy is a better phantom for DTI QC
than CPs.
|
4504. |
21 |
Examination of Tensor
Estimation Methods for Cervical Spinal Cord DTI in Pediatric
Subjects with Spinal Cord Injury and Typically Developing
Subjects ![](play.gif)
Devon M. Middleton1,2, Nadia Barakat3,
Sphoorti Shellikeri4, Scott H. Faro1,2,
MJ Mulcahey3,5, and Feroze B. Mohamed1,2
1Department of Engineering, Temple
University, Philadelphia, PA, United States, 2Department
of Radiology, Temple University, Philadelphia, PA,
United States, 3Shriners
Hospital for Children, Philadelphia, PA, United States, 4Childrens
Hospital of Philadelphia, Philadelphia, PA, United
States, 5Thomas
Jefferson University, Philadelphia, PA, United States
This study examines the effects of three different
tensor estimation methods (linear least squares, robust
outlier rejection, and linear least squares with
non-positive tensor removal) on FA and MD in the
cervical spinal cord for pediatric subjects. Both
typically developing and injured subjects were examined.
|
4505. |
22 |
Temperature-controlled
Isotropic Diffusion Phantom with Wide Range of Apparent
Diffusion Coefficients for Multicenter Assessment of Scanner
Repeatability and Reproducibility ![](play.gif)
Michael A. Boss1, Thomas L. Chenevert2,
John C. Waterton3,4, David M. Morris4,
Hossein Ragheb4, Alan Jackson4,
Nandita deSouza5, David J. Collins5,
Bernard E. van Beers6, Philippe Garteiser6,
Sabrina Doblas6, Stephen E. Russek1,
Kathryn E. Keenan1, Edward F. Jackson7,
and Gudrun Zahlmann8
1National Institute of Standards and
Technology, Boulder, CO, United States, 2University
of Michigan, Ann Arbor, MI, United States, 3AstraZeneca,
Macclesfield, United Kingdom, 4University
of Manchester, Manchester, United Kingdom, 5The
Institute of Cancer Research, Sutton, Surrey, United
Kingdom,6INSERM, France, 7University
of Wisconsin, Madison, WI, United States, 8F.
Hoffman-La Roche Ltd., Basel, Switzerland
We designed and built an ADC phantom to cover a wide
range of physiologically relevant ADC values. The
phantom used aqueous solutions of polyvinylpyrrolidone (PVP),
and we maintained constant temperature by filling the
phantom with ice water. The phantom was scanned at three
sites (1.5 and 3.0 T) to assess variability of ADC
measurement. We found excellent intrascanner
repeatability and good reproducibility across systems
and field strengths. There was non-negligible
variability only for the highest concentrations of PVP,
representing ADCs less than 0.3 x 10-3 mm2/s.
The ADC of water at 0 °C was in excellent agreement
with literature values of 1.1 x 10-3 mm2/s.
|
4506. |
23 |
Quantitative Imaging
Network Demonstration of ADC Nonlinearity Bias in
Multi-center Trials ![](play.gif)
Dariya Malyarenko1, David Newitt2,
Alina Tudorica3, Robert Mulkern4,
Karl G. Helmer5, Michael A. Jacobs6,
Lori Arlinghaus7, Thomas Yankeelov7,
Fiona Fennessy4, Wei Huang3, Nola
Hylton2, and Thomas L. Chenevert1
1Radiology, University of Michigan, Ann
Arbor, MI, United States, 2Radiology
and Biomedical Imaging, University of California San
Francisco, San Francisco, CA, United States, 3Oregon
Health and Science University, Portland, OR, United
States, 4Dana
Faber Harvard Cancer Center, Harvard Medical School,
Boston, MA, United States, 5Athinoula
A. Martinos Center for Biomedical Imaging, Massachusetts
General Hospital, Boston, MA, United States, 6John
Hopkins University School of Medicine, Baltimore, MD,
United States, 7Vanderbilt
University Institute of Imaging Science, Vanderbilt
Unversity, Nashville, TN, United States
Multi-center clinical trials seek to establish
confidence levels for quantitative diffusion
measurements. Scanner-specific gradient nonlinearity
bias was observed for off-center measurements and
implicated as a major source of potential
reproducibility error in ADC mapping for some scanners.
A practical procedure was developed to empirically
characterize the systematic nonlinearity bias across
diverse clinical MRI platforms. The results are
demonstrated for representative MRI scanners utilized in
clinical oncology trials supported by the NCI
Quantitative Imaging Network (QIN).
|
4507. |
24 |
Estimation of brain
perfusion using flow-compensated intravoxel incoherence
motion MRI: a simulation study ![](play.gif)
Yen-Peng Liao1, Shin-ichi Urayama1,
and Hidenao Fukuyama1
1Human Brain Research Center, Kyoto
University, Kyoto, Japan
Small blood volume of brain limits the application of
IVIM-MRI. Hypoperfusion is an important index for
diagnosis of some brain diseases. However, without
sufficient signal-noise ratio, large estimation errors
may be yielded in conditions of small cerebral blood
volume (CBV) and cerebral blood flow (CBF). In this
study, we proposed a method using conventional diffusion
weighted imaging combined with flow-compensated pulses
to estimate the CBF-related parameter. Computer
simulation was performed to evaluate the accuracy and
precision in heterogeneous brain tissues. The results
showed that the proposed method can estimate extremely
low CBF with better precision than the conventional
fitting method.
|
|
|
|
ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Tractography
Wednesday 14 May 2014
Exhibition Hall |
14:30 - 15:30 |
|
|
|
Computer # |
|
4508. |
25 |
Probabilistic mapping of
brain connectivity in the IIT Human Brain Atlas ![](play.gif)
Anna Varentsova1, Shengwei Zhang2,
and Konstantinos Arfanakis2,3
1Department of Physics, Illinois Institute of
Technology, Chicago, IL, United States, 2Department
of Biomedical Engineering, Illinois Institute of
Technology, Chicago, IL, United States, 3Rush
Alzheimer's Disease Center, Rush University, Chicago,
IL, United States
The IIT Human Brain Atlas project is in the 4th year of
development (www.nitrc.org/projects/iit2). The latest
version of the atlas contains high-quality artifact-free
anatomical, DTI, HARDI templates, and probabilistic gray
matter (GM) labels of the adult human brain in ICBM-152
space. The project is currently focusing on the
development of a probabilistic white matter atlas that
is complementary to the GM atlas, by performing
tractography in the state-of-the-art HARDI template
using the labels of the GM atlas as seeds. The present
work aimed to: a) evaluate the tractography results, and
b) generate probabilistic connectivity maps for pairs of
GM labels.
|
4509. |
26 |
Model-based neuroanatomy:
Tractography validation, white-matter connections and
geometrical organization ![](play.gif)
Franco Pestilli1, Justin Solomon2,
Adrian Butscher3, and Brian Wandell1
1Psychology, Stanford University, Stanford,
CA, United States, 2Computer
Science, Stanford University, Stanford, CA, United
States, 3Max
Planck Institute for Informatics, Saarbruecken, Germany,
Germany
We present a method for validating the organization of
the white-matter tracts generated using diffusion
weighted MRI and fiber tractography. Unlike previous
techniques, our method locally determines the quality of
each fascicle by associating nodes on each fascicle with
nonnegative weights. These weights are optimized to
predict the diffusion signal while also exhibiting
smoothness along the fiber path. We find that different
tractography algorithms generate different white-matter
geometries. After cross-validation using our localized
fascicle weights, however, we can describe the geometry
of fascicles in white matter with confidence that our
result is not a by-product of the choice of tractography
techniques.
|
4510. |
27 |
Visualizing complex white
matter anatomy in the live monkey at 3T using
super-resolution track density imaging ![](play.gif)
Louise Emsell1,2, Thijs Dhollander2,
Koen Nelissen3, Ronald Peters1,2,
Wim Vanduffel3, and Stefan Sunaert1,2
1Translational MRI, Imaging & Pathology, KU
Leuven & Radiology, University Hospitas Leuvenl, Leuven,
Belgium, 2Medical
Imaging Research Center, Leuven, Belgium, 3Laboratorium
voor Neuro-en Psychofysiologie, KU Leuven Medical
School, Leuven, Belgium
Visualising white matter anatomy in vivo at submilimetre
resolution using diffusion MRI is challenging without
access to high-field and strong gradient systems.
Short-tracks TDI (stTDI) is a post-processing technique
that allows super-resolution visualization beyond the
resolution of acquired data. In this pilot study we used
stTDI to enhance anatomical contrast in 3T monkey data
from 1.0mm3 to 0.25mm3 allowing the identification of
structures not visible on the 1.0mm3 colour FA maps
(e.g. stria medullaris, pre- and post-commissural
fornix, decussation of the superior cerebellar
peduncles). Reliability was assessed using bootstrapping
to model the effect of noise in the stTDI maps
|
4511. |
28 |
Tractography of
Richardson-Lucy Spherical Deconvolution under Rician noise
of Sparse Multiple q-shell Diffusion Imaging ![](play.gif)
Ping-Hong Yeh1, Erick Jorge Canales-
Rodríguez2, John Morissette3,
Arman A. Taheri3, Li-Wei Kuo4,
Fang-Cheng Yeh5, Wei Lui3, John
Ollinger3, Terrence Oakes3, Mark
L. Ettenhofer6, and Gerard Riedy3
1Henry Jackson Foundation for the Advancement
of Military Medicine, Bethesda, MD, United States, 2FIDMAG
Research Foundation, Germanes Hospitalaries and
CIBERSAM, Barcelona, Spain, 3National
Intrepid Center of Excellence, Walter Reed National
Military Medical Center, MD, United States, 4National
Health Research Institutes, Taiwan, 5Carnegie
Mellon University, PA, United States, 6Uniformed
Services University of the Health Sciences, MD, United
States
A variant of Richardson-Lucy (RL) spherical
deconvolution (SD) algorithm modeling Rician noise from
high angular resolution diffusion imaging (HARDI) data
has been shown efficient in recovering the fiber
orientation distribution in the low and medium SNR
range. We evaluate the performance of RL_SD
reconstruction on undersampled multiple q-shell HARDI
data acquired by a clinical 3T MR scanner within an
acceptable time frame (< 15 minutes).
|
4512. |
29 |
Graph-based fibre
tractography computing shortest paths between regions of
interest ![](play.gif)
Niklas Kasenburg1,2, Matthew Liptrot1,
Karsten M. Borgwardt2,3, Silas N. Ørting1,
Mads Nielsen1, and Aasa Feragen1,2
1University of Copenhagen, Copenhagen,
Zealand, Denmark, 2Max
Planck Institutes Tübingen, Tübingen, Baden-Württemberg,
Germany, 3Eberhard
Karls Universität Tübingen, Baden-Württemberg, Germany
We present a novel, graph-based fibre tractography
method, where the graph model can integrate any
diffusion representation provided as an ODF.
Tractography is performed by computing all possible
shortest paths between regions of interest. For each
path a confidence value is computed to assess its
quality. Voxels are scored by the average value of paths
they lie upon. Results for three different known tracts
show the robustness of the method over five healthy
subjects and a high overlap with tract atlases. The
region based approach is especially useful for creating
brain connectivity graphs while not suffering from path
length dependencies.
|
4513. |
30 |
Choosing Tractography
Parameters to Improve Connectivity Mapping ![](play.gif)
Gabriel Girard1,2, Kevin Whittingstall3,
Rachid Deriche2, and Maxime Descoteaux1
1Sherbrooke Connectivity Imaging Lab (SCIL),
Computer Science Department, Université de Sherbrooke,
Sherbrooke, Qc, Canada, 2ATHENA
Project-Team, INRIA, Sophia-Antipolis, France, 3Department
of Diagnostic Radiology, Faculty of Medicine and Health
Science, Université de Sherbrooke, Sherbrooke, Qc,
Canada
Diffusion-weighted imaging is often used as a starting
point for in vivo white matter connectivity to
reconstruct potential white matter pathways between
brain areas. Tractography algorithms have many
parameters which influence the reconstruction and
connectivity analysis. But how does one choose the best
set of parameters? In this study, we varied some of the
tractography parameters and observed the connectivity
score using the Tractometer evaluation system on the
ISBI Challenge 2013 dataset. We think this provides
useful information to choose tractography algorithms and
its parameters for connectivity study.
|
4514. |
31 |
Quantification of
voxel-wise total tract density: addressing the problems
associated with track-count mapping ![](play.gif)
Fernando Calamante1,2, Robert Elton Smith1,
J-Donald Tournier1,3, David Raffelt1,
and Alan Connelly1,2
1The Florey Institute of Neuroscience and
Mental Health, Melbourne, Victoria, Australia, 2Department
of Medicine, Austin Health and Northern Health,
University of Melbourne, Melbourne, Victoria, Australia, 3Centre
for the Developing Brain, King's College London, London,
United Kingdom
A biological parameter that would be valuable to draw
from a DWI experiment is the local white matter axonal
density. It has been suggested that track-density
imaging (TDI) could provide such a measure; however,
this has been the subject of controversy. The
post-processing method of SIFT was recently introduced
to minimise tractography biases. Importantly, the TDI
intensity following SIFT ideally corresponds to the DC
term of the FOD spherical harmonic expansion. We
characterise the TDI reproducibility with and without
SIFT pre-processing, as well as the reproducibility of
DC maps, to determine the most appropriate method for
quantifying voxel-wise fibre densities.
|
4515. |
32 |
Anatomical Priors to
improve Global Tractography ![](play.gif)
Alia Lemkaddem1, Didrik Skiöldebrand1,
Alessandro Dal Palú2, Jean-Philippe Thiran1,3,
and Alessandro Daducci1
1Signal Processing Laboratory (LTS5), Ecole
Polytechnique Fédérale de Lausanne (EPFL), Lausanne,
Switzerland, 2Department
of Mathematics and Computer Science, University of
Parma, Italy, 3Department
of Radiology, University Hospital Center (CHUV) and
University of Lausanne (UNIL), Switzerland
Despite the improved robustness of current global
tractography methods, the computation time makes them
still not clinically feasible. Furthermore, the
inclusion of anatomical priors are missing, i.e that the
fiber starts and terminates in the gray matter. The
latter constraint is thus crucial when performing
connectivity studies, as it is mandatory to asses which
pair of cortical regions a fiber is connecting. In this
work, we have reformulated global tractography to reduce
the computation time and furthermore embedded anatomical
priors. We compare our results to state-of-the-art
global tractography methods and therefore show how we
improve.
|
4516. |
33 |
Automated extraction of
fiber bundles for population studies ![](play.gif)
Birkan Tunc1, William A. Parker1,
and Ragini Verma1
1Department of Radiology, University of
Pennsylvania, Philadelphia, PA, United States
In this work, we design a framework for extraction of
fiber bundles by introducing a group-wise consistent
fiber clustering. This consists of defining a
connectivity based fiber representation, using this
representation to design a fiber atlas, and finally a
subsequent adaptive clustering of a new subject based on
this atlas. The connectivity based fiber representation
encodes information related to the connectivity
signatures of fibers. The fiber atlas is generated using
several representative scans. The fibers of a new
subject is clustered adaptively by incorporating this
atlas as a prior. This whole framework results in a
population consistent automated fiber clustering.
|
4517. |
34 |
A method for evaluating the
similarity of HARDI-based fiber tracking methods ![](play.gif)
Jian Lin1, Ken Sakaie1, Myron
Zhang2, Katherine A Koenig1,
Stephen E Jones1, and Mark J Lowe1
1Cleveland Clinic, Cleveland, OHIO, United
States, 2The
Ohio State College of Medicine, OSU, Columbus, OHIO,
United States
Tractography can be sensitive to a number of parameters.
However, there are few methods for quantifying such
sensitivity. We demonstrate a means for quantitative
comparison of pathways by comparison with an ensemble of
tracks. We apply the method to compare the results of
two probabilistic tractography methods: a
computationally intensive Monte Carlo (MC) approach and
fast partial differential equations (PDE) that is
designed to rapidly replicate the results of the MC
approach.
|
4518. |
35 |
Alteration of White Matter
Networks in Unilateral Mesial Temporal Sclerosis Identified
by The Whole Brain Tract-Based Automatic Analysis ![](play.gif)
Yao-Chia Shih1,2, Yun-Chin Hsu2,
Horng-Huei Liu3, and Wen-Yih Isaac Tseng2
1Institute of Biomedical Engineering,
National Taiwan University, Taipei, Taipei, Taiwan, 2Center
for Optoelectronic Medicine, National Taiwan University
College of Medicine, Taipei, Taipei, Taiwan, 3Department
of Neurology, National Taiwan University Hospital,
Taipei, Taipei, Taiwan
Patients with unilateral mesial temporal sclerosis(MTS)
were shown to have extensive gray matter (GM) and white
matter (WM) abnormalities ipsilateral and contralateral
to the seizure onset area. The changes of the whole
brain WM tracts in MTS still remain unclear. In this
study, we proposed a new method to perform
tract-specific analysis over the whole brain, named
tract-based automatic analysis (TBAA), using a diffusion
spectrum imaging (DSI) template and a tract atlas. We
hypothesized that left and right MTS would affect WM
tract integrity over the whole brain and have different
epileptic networks. In conclusion, we successfully
identified different epileptic networks in left and
right MTS, and found more extensive WM alterations in
right MTS than in left MTS.
|
4519. |
36 |
Impact of simulated lesions
on communicability metrics of the brain structural network ![](play.gif)
Jennifer Andreotti1, Kay Jann1,2,
Lester Melie-Garcia1,3, Stéphanie
Giezendanner1, Thomas Dierks1, and
Andrea Federspiel1
1Department of Psychiatric Neurophysiology,
University Psychiatric Hospital, Bern, BE, Switzerland, 2Department
of Neurology, University of California Los Angeles, Los
angeles, California, United States, 3Department
of Neuroinformatics, Cuban Neuroscience Center, Havana,
Havana, Cuba
Communicability is a wider measure of network
connectivity based on the idea that any path between two
nodes will contribute to the total flow of information.
Previous studies suggest that communicability may be
sensitive to reorganizational changes of the brain
network following a lesion. In our study the sensitivity
of communicability related metrics was assessed using
simulated lesions modelled as attacks to nodes and
single edges. Our analysis confirmed that
communicability metrics are an interesting tool to study
the effects of lesions as they are sensitive to changes
in the networks also in regions distant from the main
lesion focus.
|
4520. |
37 |
Evidence of brain damage in
neuro asymptomatic HIV positive subjects kept on immune
surveillance – A DTI study ![](play.gif)
Namita Singh Saini1, Giriraj Singh Gujral2,
Richa Trivedi3, Archana Kumari3,
Prabhjot Kaur3, Pawan Kumar3,
Subhash Khushu3, and Rajender Prasad Tripathi3
1NMR, INMAS, Delhi, Delhi, India, 2Radiodiagnosis,
Command Hospital Southern Command, Pune, Maharashtra,
India, 3INMAS,
Delhi, India
Neurological damage in HIV infection ranges from Minor
Cognitive Motor Dysfunction in the neuroasymptomatic
stage to frank HIV associated dementia later,
necessitating placement under Highly Active Anti
Retroviral Therapy (HAART). Conventional MRI is unable
to detect abnormalities in the early stages while
Diffusion Tensor Imaging shows reduced Fractional
Anisotropy (FA) in Corpus Callosum in later stages. In a
cohort of neuroasymptomatic HIV positive individuals we
have found evidence of motor progression and reduced FA
in Corticospinal Tract even in subjects with CD4 counts
above 250, indicating disease progression. Thus DTI
instead of CD4 could determine necessity for HAART
cover.
|
4521. |
38 |
Independent component
analysis with ball-stick model tractography to solve an
intra-voxel crossing fiber problem in clinical DTI data
-permission withheld
Jeong-Won Jeong1,2
1Pediatrics and Neurology, Wayne State
University, Detroit, Michigan, United States, 2PET
center, Children's Hospital of Michigan, Detroit,
Michigan, United States
The present study investigates whether independent
component analysis with ball-stick model (ICA+BSM)
analysis can estimate accurate orientation of multiple
fiber bundles in clinical DTI. Simultaion studies
assessing the absolute errors for two and three fibers
per voxel demonsrated that ICA+BSM provides promising
accuracy (median value of error angle = 4.1 ° and 10.4 °
for two and three fiber crossing, respectively) even at
b-value =1000 s/mm2 and
12 encoding gradients. A preliminary human study
suggests these errors may be marginal to isolate three
crossing pathways, copus callosum, arcuate fasciculus,
and cortico-spinal tracts in the lateral regions of
central gyrus/sulcus.
|
4522. |
39 |
Assessing Test-Retest
Reliability of Quantitative Tractography Based on Diffusion
Spectrum Imaging ![](play.gif)
Durai Arasan1, Wang Zhan1, and
Luiz Pessoa1
1University of Maryland, College Park, MD,
United States
Compared with diffusion tensor imaging (DTI) techniques,
diffusion spectrum imaging (DSI) has demonstrated its
superiority in characterizing complex diffusion patterns
related to multiple fiber structures within a single
imaging voxel. However, the test-retest reliability of
DSI-based tractography remains unclear since assessments
so far were generally based on DTI only. Here we present
a study to investigate the test-retest reliability of a
set of tracts in a group of healthy subjects, with 4
independent DSI scans for each. The outcome tractography
measurements, such as fiber counts and tract length,
show higher test-retest reliability than previously
reported DTI results.
|
4523. |
40 |
Analysis of the generalized
fractional anisotropy in regions of fiber crossings: a
simulation study
-permission withheld
Jennifer Andreotti1, Alessandra Griffa2,
Thomas Dierks1, Andrea Federspiel1,
and Patric Hagmann2,3
1University Psychiatric Hospital, Bern, BE,
Switzerland, 2Swiss
Federal Institute of Technology, Lausanne, VD,
Switzerland, 3CHUV,
Lausanne, VD, Switzerland
Quantitative tractography methods require a detailed
characterization of tissue properties specific to each
white matter (WM) fiber tract. In our study Monte-Carlo
simulations are used to understand how the generalized
fractional anisotropy (GFA) is affected in the case of
variable configurations of WM fiber tracts crossings. In
particular, a linear sum of specific anisotropy measures
for each of the tracts (linGFA) is compared to the usual
GFA. The analysis shows that, compared to standard GFA,
linGFA has a more linear relationship with the
underlying characteristics of each of the fiber tracts
and hence would be beneficial for quantitative
tractography studies.
|
4524. |
41 |
Robust Automated
Tractography of the Brain using Diffusion Spectrum Imaging ![](play.gif)
Ek T Tan1, Xiaofeng Liu1, Aziz M
Ulug2, Peter B Kingsley3, Anil K
Malhotra2,3, Delbert G Robinson2,3,
Philip R Szeszko2,3, and Luca Marinelli1
1GE Global Research, Niskayuna, NY, United
States, 2Feinstein
Institute for Medical Research, Manhasset, NY, United
States, 3North
Shore-LIJ Health System, Manhasset, NY, United States
Brain tractography is a manually-intensive and
operator-dependent task, requires anatomical knowledge,
and is inaccurate in regions containing crossing-fibers.
We propose a robust, automated seeding method that
performs image registration (1) to a predefined seeding
template, and (2) multi-fiber tractography using
compressed-sensing-accelerated diffusion spectrum
imaging (CS-DSI). Because the method uses simple
spherical ROIs, seeds can be easily adjusted on a manual
basis to optimize tract identification. The automated
algorithm was evaluated on CS-DSI data acquired in six
healthy volunteers and seven patients with
schizophrenia. The proposed method simplifies
tractography workflow, and may provide improved
reproducibility in studies utilizing diffusion
tractography.
|
4525. |
42 |
Diffusion Kurtosis Imaging
based Tractography ![](play.gif)
Rafael Neto Henriques1,2, Luis Lacerda2,3,
Rita Nunes2, Marta Morgado Correia1,
and Hugo Alexandre Ferreira2
1Cognition and Brain Science Unit, Medical
Research Council, Cambridge, United Kingdom, 2Institute
of Biophysics and Biomedical Engineering, Faculty of
Sciences of the University of Lisbon, Lisbon, Portugal, 3Centre
for Neuroimaging Sciences, Institute of Psychiatry,
King's College London, London, United Kingdom
Diffusion kurtosis Imaging (DKI) is an extension of
diffusion tensor imaging. In addition to the diffusion
tensor, DKI estimates a diffusion kurtosis tensor which
provides an indirect measure of tissue heterogeneity.
Moreover, previous studies show that the diffusion
kurtosis tensor can help resolve crossing fibres. Thus,
DKI-based tractography algorithms can be advantageous
for visualization of crossing white matter pathways in
clinical applications since they require less data and
hence shorter scanning times relative to HARDI methods.
Here, two tractography algorithms based on DKI are
evaluated, one of which is shown to be able to resolve
fibers crossing up to 45º.
|
4526. |
43 |
Diffusion Tensor Imaging of
the kidneys: functional assessment in the renal artery
stenosis ![](play.gif)
Caterina Gaudiano1, Fiorenza Busato1,
Beniamino Corcioni1, Valeria Clementi2,
Emma Fabbri3, Paola Berardi3, and
Rita Golfieri1
1Radiology Unit, Sant'Orsola-Malpighi
Hospital, Bologna, Bologna, Italy, 2Clinical
Science Development Group, GE Healthcare, Bologna,
Italy, 3Medical
Physics Department, Sant'Orsola-Malpighi Hospital,
Bologna, Bologna, Italy
We studied 17 renal patients with RAS detected by using
CE-MRA and 15 control subjects with 1.5 T MRI scanner
adding DTI to the standard protocol. The comparison
between the two groups showed that medullary ADC/FA in
the study group were significantly lower than in the
control group (P=0.034 and 0.022, respectively); there
was no significant difference for the other parameters.
This suggests that DTI could be a useful tool in
evaluating renal alteration in hemodynamic RAS.
|
4527. |
44 |
Evaluation of diffusion
acquisition and tractography methods for neurosurgical
planning systems ![](play.gif)
Jonathan Ashmore1, Flavio Dell'Acqua2,
Ruth O'Gorman3, Gareth Barker2,
and Jozef Jarosz1
1Neuroradiology, Kings College Hospital,
London, United Kingdom, 2Department
of Neuroimaging, Kings College London, London, United
Kingdom, 3University
Children's Hospital, Zurich, Switzerland
The purpose of this study was to investigate how
diffusion acquisition parameters including the number of
diffusion directions, the use of cardiac gating and the
use of non-isotropic versus isotropic voxels impacts on
tractography of the corticospinal tract for application
to neurosurgical planning. We consider the tractography
generated from a regulatory approved neurosurgical
planning system to those produced from research software
which incorporates constrained spherical deconvolution
and probabilistic tractography. All tractography results
are assessed against cyctoarchitectonic maps of the
corticospinal tract which is used as a gold standard to
asses the validity of the generated tracts.
|
4528. |
45 |
Towards minimizing
tractography errors and quantifying fiber crossing ratios ![](play.gif)
Stefan Sommer1,2, Sebastian Kozerke1,
Erich Seifritz2, and Philipp Staempfli2
1Institute for Biomedical Engineering, ETH
Zurich, Zurich, Zurich, Switzerland, 2Departement
of Psychiatry, Psychotherapy and Psychosomatics, Zurich
University Hospital of Psychiatry, Zurich, Zurich,
Switzerland
A fundamental problem of tracking techniques based on
high angular resolution diffusion data is that a
quantitative evaluation of the resulting fiber tracts is
still error prone and dependent on the algorithm and
anatomy of interest. Furthermore, it remains challenging
to derive e.g. crossing ratios of two or more
intersecting fiber populations in a robust and
reproducible manner. In this work, we present a method
to minimize fiber tracking errors of any tracking
algorithm in order to improve the quality of fiber
tracts and fiber quantification of fiber crossing
ratios. The method is validated using synthetic data and
in-vivo data.
|
4529. |
46 |
Orientation-dependent
rendering of diffusion fiber tractography streamlines for
improved visualization of complex tissue organization ![](play.gif)
Chantal M.W. Tax1, Marijn van Stralen1,
Max A. Viergever1, Nick Ramsey2,3,
and Alexander Leemans1
1Image Sciences Institute, University Medical
Center Utrecht, Utrecht, Utrecht, Netherlands, 2Rudolf
Magnus Institute of Neuroscience, University Medical
Center Utrecht, Utrecht, Utrecht, Netherlands, 3Department
of Neurology and Neurosurgery, University Medical Center
Utrecht, Utrecht, Utrecht, Netherlands
The complex nature of diffusion MRI data has triggered
the development of new approaches to visualize the
architectural organization of diffusion MRI
trajectories, which is becoming increasingly important
with emerging human connectome studies and the growing
interest of applying diffusion MRI tractography in
clinical applications. We propose a visualization
approach that interactively and selectively visualizes
these tracts based on their local orientation, by
applying an orientation-dependent transparency rendering
to the fiber pathways. This greatly improves the
visualization and exploration of the 3D architectural
organization of pathways and the underlying tissue
configurations that otherwise would be largely covered
by other pathways.
|
4530. |
47 |
A probabilistic method for
unbiased longitudinal tractography with application to
Huntington's disease ![](play.gif)
Anastasia Yendiki1, Martin Reuter1,
Paul Wilkens1, Herminia Diana Rosas1,
and Bruce Fischl1,2
1HMS/MGH/MIT Athinoula A. Martinos Center for
Biomedical Imaging, Charlestown, MA, United States, 2MIT
Computer Science and Artificial Intelligence Laboratory,
Cambridge, MA, United States
We propose a probabilistic method for reconstructing
white-matter pathways from longitudinal diffusion MRI
data. We model the posterior probability of a pathway
given a subject's full longitudinal data set, including
diffusion and structural images from all time points.
Our method is unbiased, making no assumptions on the
direction of longitudinal change. By design, it allows
longitudinal analysis of anisotropy and diffusivity
measures to be performed as a function of position along
the trajectory of a tract. We demonstrate that our
longitudinal tractography improves both specificity and
sensitivity compared to the conventional approach of
performing tractography in each time point
independently.
|
4531. |
48 |
A High-Resolution
Cardiomyofiber Atlas of the C57BL/6 Murine Heart ![](play.gif)
Stelios Angeli1, Nicolas Befera2,
Jean-Marc Peyrat3, Evan Calabrese2,
George Allan Johnson2, and Christakis
Constantinides1,4
1University of Cyprus, Nicosia, Nicosia,
Cyprus, 2Duke
University Medical Center, Durham, NC, United States, 3Qatar
Robotic Surgery Centre, Doha, Qatar,4Chi
Biomedical Ltd, Nicosia, Cyprus
|
|
|
|
ELECTRONIC
POSTER SESSION ○ DIFFUSION |
Diffusion Applications
Wednesday 14 May 2014
Exhibition Hall |
14:30 - 15:30 |
|
|
|
Computer # |
|
4532. |
49 |
White matter tract atlas on
NTU-DSI-122 template ![](play.gif)
Yu-Chun Lo1, Yung-Chin Hsu1,
Yu-Jen Chen1, and Wen-Yih Isaac Tseng1,2
1Center for Optoelectronic Medicine, National
Taiwan University College of Medicine, Taipei, Taiwan, 2Graduate
Institute of Brain and Mind Sciences, National Taiwan
University, Taipei, Taiwan
White matter tract atlas has gained interests in the
neuroscience community because it provides 3D anatomy of
white matter fiber pathways in the human brain.
Recently, we constructed a diffusion spectrum imaging (DSI)
template (NTU-DSI-122) from 122 healthy adults¡¦ DSI
datasets. ¡§Difficult¡¨ fiber pathways which are of
small sizes or have frequent crossings with other fiber
tracts were reconstructed on the template. The tract
atlas can be used to understand the geometric features
of the white matter fiber pathways. Moreover, It allows
us to implement a template-based approach that enables
the microstructural integrity of the tracts in the human
brain.
|
4533.
![](MAGNA25.jpg) |
50 |
Aging in White Matter
Revealed by Diffusional Kurtosis Imaging ![](play.gif)
Nan-Jie Gong1,2, Chun-Sing Wong1,
Chun-Chung Chan3, Lam-Ming Leung4,
Yiu-Ching Chu5, and Queenie Chan6
1Diagnostic Radiology, The University of Hong
Kong, Hong Kong, China, 2Radiology,
Stanford University, Stanford, CA, United States, 3Geriatrics
& Medicine, United Christian Hospital, Hong Kong, China, 4Psychiatry,
United Christian Hospital, Hong Kong, China, 5Radiology,
Kwong Wah Hospital, Hong Kong, China, 6Philips
Healthcare, Hong Kong, China
We utilized DKI, and for the first time a
white-matter-model that provided metrics of explicit
neurobiological interpretations in cognitive aging
adults. Whole brain TBSS and regional results suggested
that age-related white matter degenerations were broadly
driven by axonal loss across nearly all tracts. In the
anterior brain which is mostly composed of the late-myelinated
fibre tracts, demyelination was also a major mechanism
contributing to disintegration. Such probable
coexistence of both mechanisms was in line with the
Wallerian degeneration theory and is more supportive of
the anterior-posterior gradient degeneration than the
retrogenesis theory.
|
4534. |
51 |
Correlation of DTI measures
with neuropsychological scores in HIV-seropositive children ![](play.gif)
Bhaswati Roy1, Rakesh K Gupta1,
Richa Trivedi2, Alok Kumar Singh3,
Ravindra Kumar Garg3, Yogita Rai4,
Vimla Venkatesh5, Mukesh Tripathi6,
and Chandra M Pandey7
1Radiology & Imaging, Fortis Memorial
Research Institute, Gurgaon, Haryana, India, 2NMR
Reseach Centre, Institute of Nuclear Medicine and Allied
Sciences, Delhi, Delhi, India, 3Neurology,
King George's Medical University, Lucknow, Uttar
Pradesh, India, 4Radiodiagnosis,
Sanjay Gandhi Post Graduate Institute of Medical
Sciences, Lucknow, Uttar Pradesh, India, 5Microbiology,
King George's Medical University, Lucknow, Uttar
Pradesh, India,6Anaesthesiology, Sanjay
Gandhi Post Graduate Institute of Medical Sciences,
Lucknow, Uttar Pradesh, India, 7Biostatistics
& Health Informatics, Sanjay Gandhi Post Graduate
Institute of Medical Sciences, Lucknow, Uttar Pradesh,
India
With an aim to assess the integrity of white matter in
HIV positive pediatric patients, DTI and
neuropsychological test battery was performed on 38
HIV-seropositive and 8 HIV-seronegative children born to
HIV-seropositive mothers of same socioeconomic status.
Voxel wise-based technique was implemented for the
analysis of DTI data of participants. We observed
significant changes in FA values in the corpus callosum,
corona radiata, internal capsule. Significant direct
correlation was also observed between FA and cognition
scores relating to memory function. DT MRI could be used
as an early objective marker of HIV related
microstructural brain changes.
|
4535. |
52 |
Differences in diffusional
changes of the optic pathways between Multiple Sclerosis and
Neuromyelitis Optica using Diffusional Kurtosis Imaging ![](play.gif)
Mariko Yoshida1, Masaaki Hori1,
Kazumasa Yokoyama2, Nozomi Hamasaki1,
Michimasa Suzuki1, Koji Kamagata1,
Kohei Kamiya1, Shigeki Aoki1,
Yoshitaka Masutani3, and Nobutaka Hattori2
1Department of Radiology, Juntendo University
School of Medicine, Bunkyo, Tokyo, Japan, 2Department
of Neurology, Juntendo University School of Medicine,
Tokyo, Japan, 3Division
of Radiology and Biomedical Engineering, Graduate School
of Medicine, The University of Tokyo, Tokyo, Japan
The purpose of this study is to evaluate differences in
diffusional changes of the optic pathways between
multiple sclerosis (MS) and neuromyelitis optica (NMO)
using a new method, diffusional kurtosis imaging (DKI)
Six NMO, eight MS, and seven healthy volunteers
participated in this study. DKI sensitively detected
abnormalities in optic tract in NMO patients. According
to the past reports, NMO-immunoglobulin G targeting AQP4
is often observed in optic tact. DKI may be a more
sensitive biomarker to differentiate between MS and NMO
than conventional diffusional evaluations, such as
diffusion tensor imaging.
|
4536. |
53 |
Enhanced Contrast of
Ischemic Stroke Lesions in Non-Gaussian Diffusion Imaging ![](play.gif)
Farida A. Grinberg1, Ezequiel Farrher1,
Luisa Ciobanu2, Françoise Geffroy2,
Denis Le Bihan2, and N. Jon Shah1,3
1Forschungszentrum Juelich, Juelich, Germany, 2Neurospin,
CEA, France, 3RWTH
Aachen University, Germany
We compare a sensitivity of two non-Gaussian diffusion
models with the gold standard ADC approach in providing
the contrast for ischemic lesions in animals: the
stretched-exponential and gamma-distribution functions.
Both functions provide good fits in the extended range
of the diffusion weightings and allow for an enhanced
contrast of the lesions. An interesting finding of this
work is the appearance of laminar cortical structures in
stroke lesions clearly visualised by the parameter maps
of the investigated models but hardly observable in the
ADC-maps.
|
4537. |
54 |
Repeatability investigation
and radiologic assessment of reduced field of view DWI on
thyroid glands ![](play.gif)
Yonggang Lu1, Vaios Hatzoglou1,
Hilda E. Stambuk1, Suchandrima Banerjee2,
Ajit Shankaranarayanan2, Yousef Mazaheri1,
Joseph O. Deasy1, and Amita Shukla-Dave1
1Memorial Sloan-Kettering Cancer Center, NEW
YORK, New York, United States, 2Global
Applied Sciences Laboratory, GE Healthcare, Menlo Park,
California, United States
This study investigated the repeatability and assessed
the radiologic quality of reduced field of view
diffusion weighted imaging (rFOV DWI) in thyroid glands
of healthy human volunteers. Repetitive DWI scans were
performed on each subject within the same scan exam and
across scan exams. Image qualities were scored and
apparent diffusion coefficient (ADC) values were
calculated on the lobes of thyroid glands and followed
by reproducibility investigation. The study demonstrated
that rFOV DWI had significantly improved image quality
but lower ADC values and lesser repeatability value of
ADC compared to the conventional DWI techniques in the
region of thyroid glands.
|
4538. |
55 |
Correlation of Diffusion
Tensor Imaging (DTI) measures with memory dysfunction scores
in hypothyroid patients
Subash Khushu1, Sadhana Singh1,
Richa Trivedi1, Kavita Singh1,
Pawan Kumar1, and L Ravi Shankar2
1NMR Research Centre, INMAS DRDO, Delhi,
delhi, India, 2Thyroid
Research Centre, INMAS DRDO, Delhi, delhi, India
The aim of our study was to correlate DTI measures (FA
and MD) with memory dysfunction scores in hypothyroid
population. Diffusion tensor tractography (DTT) and PGI-memory
scale (PGIMS) were performed on eight healthy controls
and eight hypothyroid patients. Our results showed the
inverse correlation of memory dysfunction score with FA
of WM tracts (RIFO and LIFO) and positive correlation of
memory dysfunction scores with MD of RATR fibre tract.
These findings suggest that the microstructural changes
in these WM tracts may contribute to underlying
dysfunction in memory in hypothyroidism.
|
4539. |
56 |
IVIM-DTI of Healthy Human
Liver ![](play.gif)
Oi Lei Wong1,2 and
Michael D Noseworthy3,4
1Department of Medical Physics and Applied
Radiation Science, McMaster University, Hamilton,
Ontario, Canada, 2Medical
Physics and Research Department, Hong Kong Sanatorium &
Hospital, Hong Kong, Hong Kong, Hong Kong, 3Department
of Electrical and Computer Engineering, McMaster
University, Hamilton, Ontario, Canada, 4Imaging
Research Center, St.Joseph's Healthcare, Hamilton,
Ontario, Canada
Both IVIM and DTI are well recognized MRI methods for
quantifying flow and diffusion, respectively.
Simultaneously assessing both techniques (IVIM-DTI) has
recently been shown feasible in the kidney. We proposed
that the same technique is also feasible in the liver
with multiple breath holds and subsequent retrospective
motion compensation. Based on our result, IVIM-DTI
analysis is able to differentiate between hepatic blood
vessels and liver parenchyma, while minimizing the
pseudo-hepatic artifact.
|
4540. |
57 |
Assessment of aquaporins
function in stages of liver fibrosis using multi-b diffusion
weighted magnetic resonance imaging ![](play.gif)
LI Qiu-ju1, ZHANG Zi-heng2, LI
Jia-hui1, YU Bing1, ZHANG Xin1,
ZHAO Zhou-she2, SHI Yu1, XIN Jun1,
and GUO Qi-yong1
1Radiology, Shengjing Hospital of China
Medical University, Shenyang, Liaoning, China, 2General
Electronic Company Healthcare (China), Beijing, China
A multi-b diffusion weighted MR imaging measurement was
performed to examine the effects of AQP inhibition to
normal and liver-fibrotic rats in vivo. At low-b values,
the resulted ADCs reflected the hepatic blood perfusion
information while the functional changes of the AQPs on
cell membranes at high b values. The AQP1 expression in
the liver endothelial cells increased with aggravation
of liver fibrosis. An increase of perfusion was observes
at S1, but a decrease occurred with the addition of
inhibitor. At S2, perfusion decreased, and further
decreased with inhibitor. The inhibition tests were all
negative.
|
4541. |
58 |
Sensitivity and specificity
of prostate tumor discrimination by IVIM approximation ![](play.gif)
Gina Belmonte1, Vito Biondo2,
Augusto La Penna3, Francesco Carbone4,
Gianluca Vischi5, Leonardo Semeraro5,
and Fabrizio Banci Buonamici1
1Medical Physics, University Hospital of
Siena, Siena, Italy, Italy, 2University
of Siena, Italy, Italy, 3Radiology,
University of Siena, Italy, Italy,4Radiology,
University Hospital of Siena, Italy, Italy, 5Radioterapy,
University of Siena, Italy, Italy
We analyzed precision and accuracy in the discrimination
of prostate tumor of IVIM parameters measured with a
bi-exponential fit and a simplified approach, that
allows to estimate the diffusion coefficient and the
pseudo-diffusion fraction from a 2 b-values acquisition.
ROC analysis were used to extract the optimum cut-off
for each parameter that maximize the accuracy of test.
The simplified IVIM parameters are not accurate
estimates of the corresponding ones from the
bi-exponential fit, but discriminate prostate tumor from
healthy tissues in a accurate way. This simplified
technique allows therefore to reduce the acquisition
time and preserve a good diagnostic accuracy.
|
4542. |
59 |
Age-related Changes of
Prostate Peripheral Zone in Normal Adults£ºEvaluation by DTI ![](play.gif)
tao gong1,2, bin wang1, lili li2,
and guangbin wang2
1binzhou medical university, shandong,
yantai, China, 2Shandong
Medical Imaging Research Institute, shandong, jinan,
China
The DTI parameters of MD/FA values of normal prostate
peripheral zone is different in different age groups,
and MD values were increased with age , while FA values
decreased.
|
4543. |
60 |
Differential Diagnosis of
Chest Lesions: Values of Diffusion-Weighted MR Imaging ![](play.gif)
Nan-Han Lu1,2, Tai-Been Chen2,
Yung-Hui Huang2, Hueisch-Jy Ding2,
Lee-Ren Yeh1, and Jeon-Hor Chen1,3
1Department of Radiology, E-DA Hospital,
Kaohsiung, Kaohsiung, Taiwan, 2Department
of Medical Imaging and Radiological Sciences, I-Shou
University, Kaohsiung, Kaohsiung, Taiwan, 3Functional
Onco-Imaging, Department of Radiological Sciences,
University of California Irvine, Irvin, CA, United
States
Lung cancer is the leading cause of cancer death among
men and women worldwide. The precise pre-operation
diagnosis of chest neoplasms and inflammatory nodules
using CT, MRI and PET-CT is difficult. The most
sensitive diagnostic method is the surgical biopsy. The
differences in imaging findings may reflect differences
in histopathologic features of chest lesions. On
T2-weighted MR images could not be used to distinguish
malignant from benign pulmonary nodules. On
diffusion-weighted MR imaging (DWI), the apparent
diffusion coefficient (ADC) value refers to the specific
diffusion capacity of a biologic tissue. ADC value
depends largely on the presence of barriers to diffusion
within the water microenvironment.The goal of this study
is to present a novel method for differential diagnosis
among primary chest cancers, metastatic tumors and
benign tumors using ADC standard deviation value (SD) of
diffusion-weighted MR imaging.
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DIFFUSION TENSOR IMAGING OF
CERVICAL SPINAL CORD A 3T : NORMAL VALUES OF RADIAL, AXIAL,
MEAN DIFFUSIVITY AND FRACTIONAL ANISOTROPY IN ANTERIOR HORN,
DORSAL FUNICULUS AND PYRAMIDAL TRACT AT EACH CERVICAL LEVEL ![](play.gif)
Crombé Amandine1,2, Menegon Patrice1,
Tourdias Thomas1, and Dousset Vincent1
1Department of neuroradiology, Pellegrin
Hospital, Bordeaux Segalen University, Bordeaux, France, 2ENS
Lyon, Lyon, France
From a commercially available axial SE-EPI DTI sequence,
after empirical optimizations in order to limit
distortion in an acceptable scan time, our aim was to
determine the normal values of DTI parameters (mean
diffusivity, axial diffusivity, radial diffusivity and
fractional anisotropy) in key locations of cervical
spine (cortico spinal tract, posterior column and
anterior horn, full spine section) at each cervical
level from C1 to C7.
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Spatial and voxel-wise
evaluation of eigenvector stability within the human calf at
3T ![](play.gif)
Conrad Rockel1,2 and
Michael D Noseworthy1,2
1School of Biomedical Engineering, McMaster
University, Hamilton, Ontario, Canada, 2Imaging
Research Centre, St Joseph's Healthcare, Hamilton,
Ontario, Canada
Spatial distribution of eigenvector variability was
investigated in the human calf at 3T using different
amoungs of signal averages and encoding directions. The
principal vector was found to vary much less than the
two minor vectors. Furthermore, the spatial distribution
appeared non-random and favourable to the peripheral
musles, although noisier for the minor eigenvectors. The
spatial distribution appeared dependent upon scan
acquisition conditions.
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63 |
Changes in the Medial and
Lateral Gastrocnemius Fiber Architecture with Age.
Yanjie Xue1, Usha Sinha1, Vadim
Malis1, Robert Csapo2, and
Shantanu Sinha2
1Physics, SDSU, San Diego, CA, United States, 2Radiology,
UCSD, San Diego, CA, United States
Age related changes in muscle alter fiber architecture
(fiber lengths and pennation angles). Diffusion tensor
imaging (DTI) allows the mapping of fiber architecture,
this study investigates age related changes in fiber
architecture of the medial and lateral gastrocnemius
using DTI. Ten female subjects (5 young/ 5 old) were
imaged using DTI and fiber length and pennation angles
were determined. Decreases in fiber length and pennation
angle were seen in the older cohort as well as regional
differences between distal and middle origin fibers. The
length/pennation angle changes in the LG were smaller
than those seen in the MG.
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64 |
MRI quantification of
diffusion and perfusion in bone marrow by intravoxel
incoherent motion (IVIM) and non-negative least square
(NNLS) analysis. ![](play.gif)
Giulio Gambarota1, Antoine Marchand2,
Eric Hitti1, Frederik Monge1,
Regis Duvauferrier2, Raphael Guillin2,
and Hervé Saint-Jalmes1
1Université de Rennes 1, LTSI, Rennes,
F-35000, France, 2Department
of Imaging, Rennes University Hospital, Rennes, F-35000,
France
The aim of this study was to assess the feasibility of
measuring diffusion and perfusion in vertebral bone
marrow using the intravoxel incoherent motion (IVIM)
approach and to investigate the benefits of the
non-negative least square (NNLS) technique for analysis
of IVIM data. Results indicated that, for a proper
analysis of IVIM data, the use of NNLS is essential
especially in cases where the signal-to-noise ratio is
low or where motion artifacts and other factors might
affect the data quality.
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65 |
3 Tesla Diffusion Tensor
Imaging (DTI) of Normal Uterus in Young and Middle-aged
Women during the Menstrual Cycle: an Initial Study to
Evaluate the Cyclic Changes of Fractional Anisotropy (FA)
and Apparent Diffusion Coefficient (ADC) Values ![](play.gif)
Yonglan He1, Huadan Xue2, Ning
Ding2, Yuan Li3, and Zhengyu Jin4
1Radiology, Peking Union Medical College
Hospital, Beijing, Beijing, China, 2Radiology,
Peking Union Medical College Hospital, Beijing, China, 3gynaecology
and obstetrics, Peking Union Medical College Hospital,
Beijing, China, 4Peking
Union Medical College Hospital, Beijing, China
Prospectively investigate the cyclic changes of FA and
ADC values of the normal uterus in a larger population
divided into different age groups during 4 phases of the
menstrual cycle, and the correlation with the basic
serum hormone levels in menstrual phase.
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Effects of gradient
nonlinearity correction on DTI ADC and FA measurements for
assessing breast cancer treatment response ![](play.gif)
David Newitt1, Ek Tsoon Tan2, Lisa
Wilmes1, Hee Jung Shin3, Luca
Marinelli2, and Nola Hylton1
1Radiology and Biomedical Imaging, UCSF, San
Francisco, CA, United States, 2GE
Global Research, Niskayuna, NY, United States, 3Radiology,
Asan Medical Center, University of Ulsan, Korea
Gradient nonlinearity (GN) is a significant source of
error for quantitative diffusion MRI and is of
particular concern in breast imaging where anatomy
requires large offsets from magnet isocenter. GN
correction (GNC) to correct for spatially-varying
diffusion encoding was evaluated in DTI acquired ADC and
FA of tumor and normal tissue regions in breast cancer
subjects undergoing neoadjuvant chemotherapy. GNC
resulted in a mean change in tumor ADC of -11% (range
-4% to -19%), and in FA of -6% (range -24% to 20%).
Percent change in tumor ADC between visits had an RMS
change of 3% with GNC.
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Effect of scanner and head
coil on diffusion MRI measures of the brain ![](play.gif)
Matthan W.A. Caan1, Michiel B. de Ruiter1,
Liesbeth Reneman1, and Aart J. Nederveen1
1Radiology, Academic Medical Center,
Amsterdam, Netherlands
The goal of this study was to compare diffusion
parameters between three scanners of one vendor with the
head-coils used in daily practice on the particular
scanners. Of seven subjects, diffusion weighted MRI data
were acquired on 3.0 Tesla Philips Intera, Achieva and
Ingenia scanners. Signal to Noise Ratio (SNR), Mean
Diffusivity (MD) and Fractional Anisotropy (FA) maps
were compared. Inter-scanner differences were three
times as large as intra-scanner differences. SNR varied
up to 20% between scanners, was positively associated
with MD and negatively with FA. Differences in MD and FA
up to 7% are in agreement with literature.
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Self correction of blood
flow effect for brain-fluctuation MRI
-permission withheld
Marina Takatsuji1, Toshiaki Miyati1,
Naoki Ohno1, Saori Yoshizawa2,
Tomohiro Noda1, Satoshi Kobayashi3,
Toshifumi Gabata3, and Osamu Matsui3
1Division of Health Sciences, Institute of
Sciences, Kanazawa University, Kanazawa, Ishikawa,
Japan, 2School
of Health Sciences, College of Medical, Pharmeceutical
and Health Sciences, Kanazawa University, Kanazawa,
Ishikawa, Japan, 3Department
of Radiology, School of Medical Sciences, Kanazawa
University, Kanazawa, Ishikawa, Japan
The change of the apparent diffusion coefficient (
ADC)during the cardiac cycle in the brain are affected
by the regional cerebral blood flow (rCBF). To evaluate
hemodynamic-independent water fluctuaion, we corrected
the rCBF effect by using the ECG-triggered single shot
diffusion echo planner data itself. We corrected the the
changes of ADC (ĢADC) by the maximum ADC with b=0-200
having the highest correlation with the rCBF. There was
no significant correlation between corrected-ĢADC and
eCBF. Corrected-ĢADC makes it possible to obtain the
degree of fluctuation of the water molecules
hemodynamic-in the brain.
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Reproducibility of
Diffusion Weighted MRI under Active Breathing Coordinator
control ![](play.gif)
Evangelia Kaza1, David Collins1,
Richard Symonds-Tayler1, Rafal Panek1,
and Martin Osmund Leach1
1CR-UK and EPSRC Cancer Imaging Centre,
Institute of Cancer Research and Royal Marsden Hospital,
Sutton, Surrey, United Kingdom
The feasibility of diffusion-weighted (DW) MRI
automatically acquired during breath holding enforced by
a modified, MR-compatible Active Breathing Coordinator
(ABC) system was demonstrated on healthy volunteers. The
position of abdominal organs, major vessels and the
diaphragm was shown to be reproducible between different
measurements under ABC control at the same inhaled air
volume and unaffected by changes of non-spatial sequence
parameters. The observed repeatability of organ position
using the ABC device suggests that DW-MRI with
controlled lung volume can be matched to CT images
acquired with the same ABC settings and thus support
radiotherapy treatment planning.
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4553. |
70 |
In vivo detection of sexual
dimorphisms in the brain of a Passerine songbird, a
proof-of-principle study ![](play.gif)
Julie Hamaide1, Geert De Groof2,
Johan Van Audekerke1, Lisbeth Van Ruijssevelt1,
Zhenhua Mai1, Firat Kara1, Marleen
Verhoye1, and Annemie Van Der Linden1
1University of Antwerp, Wilrijk, Antwerp,
Belgium, 2University
of Antwerp, Antwerp, Belgium
The aim of the present study was to implement a
non-invasive in vivo diffusion tensor imaging (DTI)
protocol in the tiny zebra finch. To test for the
sensitivity of the optimized sequence, we tried to
visualize known (histology) sexual dimorphisms in adult
zebra finches. We found the known dimorphisms and
illustrate the benefit of using whole-brain in vivo MRI
by revealing novel, unexplored sexual dimorphisms in the
adult zebra finch brain.
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Structure Specific Analysis
of white and gray matter in the rat brain after exposure to
chronic stress ![](play.gif)
Philip A Cook1, Paul A Yushkevich1,
Sijie Tian2, Sandra Luz3, Seema
Bhatnagar4, and James C Gee1
1Department of Radiology, University of
Pennsylvania, Philadelphia, PA, United States, 2School
of Engineering and Applied Science, University of
Pennsylvania, Philadelphia, PA, United States, 3Children's
Hospital of Philadelphia, PA, United States, 4Anesthesiology
and Critical Care, Children's Hospital of Philadelphia
and University of Pennsylvania, Philadelphia, PA, United
States
TSA in rat brain
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Neurotoxic aspects of
tungusten Alloy Based Heavy Metals in Rat Brain: A DTI study
Ritu Tyagi1, Poonam Rana1, Richa
Trivedi1, B.S. Hemanth Kumar1,
Deepak Bhatnagar2, and Subash Khushu1
1NMR Research centre, Institute of Nuclear
Medicine and Allied Sciences (INMAS), DELHI, DELHI,
India, 2School
of Biochemistry, Devi Ahilya Vishwavidayalaya, Indore,
M.P., India
HMTAs are composed of a mixture of tungsten (91–93%),
nickel (3–5%) and either cobalt (2–4%) or iron (2–4%)
particles which are increasingly adopted as the raw
material to make parts of military products. Diffusion
tensor imaging (DTI) study was performed at day 1, day
3, and day 5 in controls and animals treated metals used
in HMTAs and their mixture. An increase in MD values
were observed in cerebral pedeuncle with cobalt and
tungsten, whereas all the three metal salts and their
mixture showed pronounced effect on the thalamic region
of the brain compared to controls.
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