Electronic Posters
: Other
|
Click on
to view the abstract pdf and click on
to view the video presentation. |
Spectroscopy - Other
Monday May 9th
Exhibition Hall |
14:00 - 16:00 |
Computer 46 |
14:00 |
3472. |
Gender
differences in GABA and glutamate concentrations
measured with MEGA-PRESS ![](play.gif)
Ruth L O'Gorman1, Lars Michels1,
Richard Edden2, and Ernst Martin1
1University Children's Hospital,
Zürich, Switzerland, 2Russell
H Morgan Department of Radiology and
Radiological Sciences, Johns Hopkins
University, Baltimore, MD, United States
Few studies have examined the normal
inter-subject variability in MRS GABA and
glutamate (Glu) concentrations with factors
like age and gender. This study investigates
age- and gender-related differences in GABA
and Glu in a group of healthy adults. No
significant age effects were seen, but GABA,
Glu, and Glx (glutamate+glutamine) levels
were significantly higher in the male
participants. These significant differences
are independent of the grey and white matter
fraction in the MRS voxel and emphasize the
importance of gender-matching for GABA and
Glu MRS studies with mixed-cohort subject
groups.
|
14:30 |
3473. |
Regional
Variations in GABA Measured with MEGA-PRESS ![](play.gif)
Christopher John Evans1, Frederic
Boy1, Richard A E Edden2,
Krish D Singh1, and Petroc Sumner1
1CUBRIC, School of Psychology,
Cardiff University, Cardiff, Wales, United
Kingdom, 2Russell
H. Morgan Department of Radiology and
Radiological Science, The Johns Hopkins
University, Baltimore, United States
In this work, we report on the regional
differences in human GABA levels, measured
with MEGA-PRESS. Six regions were studied -
anterior cingulate, dorsolateral pre-frontal
cortex, inferior frontal gyrus,
supplementary motor area, parietal lobe and
occipital lobe. There was a significant
effect of region and of voxel grey matter
fraction on GABA. The measured differences
in GABA not attributable solely to
differences in the tissue composition across
regions.
|
15:00 |
3474. |
Motor Control
Predicted by GABA Concentration in the
Supplimentary Motor Area ![](play.gif)
Christopher John Evans1, Frederic
Boy1, Richard A E Edden2,3,
Krish D Singh1, Masud Husain4,
and Petroc Sumner1
1CUBRIC, School of Psychology,
Cardiff University, Cardiff, Wales, United
Kingdom, 2Russell
H. Morgan Department of Radiology and
Radiological Science, The Johns Hopkins
University, Baltimore, United States, 3F.M.
Kirby Research Center for Functional MRI,
Kennedy Krieger Institute, Baltimore, United
States, 4UCL
Institute of Cognitive Neuroscience & UCL
Institute of Neurology, UCL, London,
England, United Kingdom
The concentration of inhibitory
neurotransmitter GABA has previously been
demonstrated to predict participants’
performance in visual behavioural tasks.
Here, we demonstrate that GABA concentration
correlates with the performance of
participants in a motor task closely
associated with behavioural inhibition (the
Negative Compatibility Effect, NCE).
Individual differences in participants' NCE
is explained by differences in participants
GABA levels in the supplementary motor area,
but not correlated with other brain regions.
|
15:30 |
3475. |
1H
MRS at 7T demonstrates a strong correlation
between stimulus-induced -frequency
in the visual cortex and the glutamine/GABA
ratio. ![](play.gif)
Mary Charlotte Stephenson1,
Matthew J Brookes1, Darren Price1,
Antonio Napolitano2, Susan T
Francis1, and Peter G Morris1
1School of Physics and Astronomy,
University of Nottingham, Nottingham,
Nottinghamshire, United Kingdom, 2Academic
Radiology, University of Nottingham, United
Kingdom
The peak frequency of stimulus-induced
visual ![lower case Greek gamma](http://submissions.miracd.com/ISMRM2011/Images/LCGreek/gamma.gif) -oscillations,
measured using magnetoencephalograpy, has
been shown to be predicted by the resting
concentration of ![lower case Greek gamma](http://submissions.miracd.com/ISMRM2011/Images/LCGreek/gamma.gif) -amino
butyric acid (GABA). However, cortical
network models show that the oscillatory
frequency depends on the balance between
excitatory and inhibitory neurotransmitters.
In this study we utilize the increased
spectral resolution and signal available at
7T to quantify glutamate, glutamine and
GABA. Our results indicate a stronger
correlation between ![lower case Greek gamma](http://submissions.miracd.com/ISMRM2011/Images/LCGreek/gamma.gif) -frequency
and glutamate/GABA than for GABA alone. The
strongest correlation was found for
glutamine/GABA where the glutamine
concentration is thought to be closely
related to the glutamate neurotransmitter
pool size
|
Tuesday May 10th
|
13:30 - 15:30 |
Computer 46 |
13:30 |
3476. |
Feasibility of
Quantitative Proton MR Spectroscopy Without
Water Suppression in In Vivo Malignant Breast
Lesions at 1.5T ![](play.gif)
Hyeon-Man Baek1
1Advanced Imaging Research
Center, UT Southwestern Medical Center,
Dallas, Texas, United States
Recently, in vivo 1H-MRS acquired with water
suppression has been proven helpful for the
detection and therapy response monitoring of
breast cancer based on total choline-containing
compounds (tCho). However, the role of
1H-MRS acquired without water suppression is
less established. The aim of our study was
to determine whether quantitative results
from the breast cancer can show good
agreement between the estimated tCho levels
in water-suppressed and unsuppressed
spectra. There was a statistically
significant correlation between the
estimated tCho concentration levels by
1H-MRS with and without water suppression
(r2 = 0.462, p =0.001). This result
demonstrates the feasibility of in vivo
quantitative 1H-MRS without water
suppression for the measurement of tCho
concentrations from in vivo malignant breast
lesions.
|
14:00 |
3477. |
Increase in
SNR for 31P MR spectroscopy by integrating
polarization transfer and direct detection in
one repetition time.
Wybe van der Kemp1, Vincent Boer1,
Peter Luijten1, Jannie Wijnen1,
and Dennis Klomp1
1Department of Radiology,
University Medical Centre, Utrecht,
Netherlands
Here we show for 31P MR spectroscopy that by
integrating polarization transfer (BINEPT)
and a spin echo (SE) in one repetition time,
one can gain extra signal to noise for the
BINEPT as compared to spectra from separate
BINEPT and SE sequences. The BINEPT signal
is hardly affected by the subsequent SE.
However, the BINEPT signal has some
saturating effect on the SE signal.
Alternatively, the integrated sequence can
be used to obtain an BINEPT at the same SNR,
but with the additional information on
metabolite content that direct detection
offers.
|
14:30 |
3478. |
Optimal
recombination of multi-coils CSI data using
image based sensitivity map ![](play.gif)
Michaël Sdika1, Yann Le Fur1,
and Patrick J Cozzone1
1CRMBM, CNRS, UMR 6612, Faculté
de Médecine de Marseille, Université de la
Méditerranée, Marseille, France
This work addresses the problem of the
optimal recombination of multi-coil chemical
shift imaging (CSI) data. Eddy current
correction is performed using the
unsuppressed water signal. Coil sensitivity
maps are computed using low resultion images
and optimal recombination formula are
derived.
|
15:00 |
3479. |
MISSA - A
highly-developed clinical tool for MR
Spectroscopy ![](play.gif)
Bernd Merkel1, Markus T. Harz1,
and Horst K. Hahn1
1Fraunhofer MEVIS, Bremen,
Germany
MR Spectroscopy hasn't found the way into
clinical routine yet. For one reason, most
of the existing devices and software
assistants lack of performance or difficult
handling. We present the novel research
prototype MISSA (MEVIS Imaging and
Spectroscopy Software Assistant) for the
analysis of single- (in vivo, ex vivo) and
multi-voxel (2D, 3D) spectroscopy. All
standard processing steps are included,
together with different quantification
methods, which can be easily extended.
Furthermore, 3D-visualization, PACS
connection and the possibility of voxel-labeling
with export to machine learning algorithms
are integrated. Therefore, it is our goal to
improve and simplify MRS data analysis.
|
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|
Electronic
Posters : Other
|
Click on
to view the abstract pdf and click on
to view the video presentation. |
Elastography
Monday May 9th
Exhibition Hall |
14:00 - 16:00 |
Computer 47 |
14:00 |
3480. |
Calculation of Shear
Stiffness in Noise Dominated Magnetic Resonance Elastography
(MRE) Data Based on Principal Frequency Estimation. ![](play.gif)
Kiaran Patrick McGee1, David Lake1,
Yogesh Mariappan1, Armando Manduca1,
Rolf Hubmayr2, and Richard Ehman1
1Department of Radiology, Mayo Clinic,
Rochester, MN, United States, 2Pulmonology
and Critical Care Medicine, Mayo Clinic, Rochester, MN,
United States
A method for calculating the shear stiffness from
magnetic resonance elastography data under conditions of
low signal-to-noise ratio (SNR) is described. It is
based on the analysis of the spectral content of the
propagating shear wave field from which the principal
spatial frequency is identified and ultimately shear
stiffness calculated. Finite element simulations and ex
vivo lung experiments were performed to evaluate the
sensitivity of this approach in comparison to the local
frequency estimation (LFE) method. Results indicate that
principal frequency analysis accurately estimates shear
stiffness in comparison to commonly applied LFE-based
estimates under low SNR conditions.
|
14:30 |
3481. |
Geometric Focusing of High
Frequency Shear Waves for Noninvasive High Resolution MR
Elastography ![](play.gif)
Thomas J Royston1, Temel Kaya Yasar1,
and Richard L Magin1
1University of Illinois at Chicago, Chicago,
IL, United States
We combine the benefits of noninvasiveness and geometric
focusing of the rapidly attenuating shear waves to
extend the useful shear wave frequency range, and thus
achieve very short shear wavelengths that will help in
providing more localized estimates of material
properties using MR elastography on in vitro tissue
specimens or materials. This is accomplished by
vibrating the entire sealed test tube axially,
effectively using the entire inner test tube wall as an
axisymmetric shear wave source that creates waves
travelling radially inward. The basic theory supporting
this approach is followed by a description of our
experimental setup and pilot results.
|
15:00 |
3482. |
Physical Boundary
Conditions Reconstruction: a Novel Method to Determine
Viscoelastic Parameters from Magnetic Resonance Elastography
Data ![](play.gif)
Philippe Garteiser1, Sabrina Doblas1,
Bernard E. VanBeers1,2, Valérie Vilgrain2,
and Ralph Sinkus1
1INSERM UMR 773, Centre de Recherche
Biomédicale Bichat-Beaujon, Clichy, France, 2Department
of Radiology, Beaujon University Hospital, Paris Diderot
University, Clichy, France
The conventional reconstruction of viscoelastic
parameters in MR-Elastography (MRE) is challenging in
the presence of the signal noise levels typically
encountered in clinical datasets. A novel algorithm is
proposed, which stabilizes the noisy wave equation
inversion problem by injecting constraints arising from
the underlying physics into the system. As a result, the
viscoelastic parameters accurately reflect the input
data while also obeying necessary basic physical
constraints, gaining stability in the process. Proof of
concept is provided on simulated noisy waves and on
clinically relevant experimental data from a cohort of
patients with diffuse liver disease.
|
15:30 |
3483. |
Hardware and Software
Design for Serial and Longitudinal Rat MR Elastography
Studies ![](play.gif)
Kevin John Glaser1, Jun Chen1,
Meng Yin1, Thomas Hulshizer1,
Phillip Rossman1, and Richard Ehman1
1Radiology, Mayo Clinic, Rochester, MN,
United States
This work demonstrates an approach to rat liver MR
elastography (MRE) designed to facilitate serial and
longitudinal studies of hepatic stiffness for
applications such as monitoring disease progression and
treatment efficacy. A large, thin driver was constructed
that allowed for rapid positioning of each animal, and a
rapid EPI MRE acquisition was used to measure liver
stiffness. Results are shown demonstrating hepatic
changes in rats due to a bile duct ligation (BDL)
surgery over 4 weeks compared to rats given a sham
surgery.
|
Tuesday May 10th
|
13:30 - 15:30 |
Computer 47 |
13:30 |
3484. |
Evaluating the Feasibility
of Multi-Slice Endorectal Magnetic Resonance Elastography
for Prostate Cancer Localization ![](play.gif)
Arvin Arani1,2, Donald Plewes1,2,
and Rajiv Chopra1,2
1Imaging Research, Sunnybrook Research
Institute, Toronto, ON, Canada, 2Medical
Biophysics, University of Toronto, Toronto, ON, Canada
Purpose: To evaluate the feasibility of multi-slice
endorectal MR elastography (MRE) over a volume
equivalent to the prostate, for the application of
identifying localized prostate cancer. Methods:
Experiments were conducted in a prostate mimicking
phantom embedded with tumour mimicking inclusions. MRE
was performed by mechanically coupling an endorectal
coil to a custom made piezoceramic actuator. Results:
Multi-slice endorectal MRE was feasible over the entire
60cc prostate volume (27 slices, 2mm slice thickness).
Conclusions: The results of this study, in combination
with the clinical availability of an endorectal coil,
motivate further investigation of endorectal MRE in
patients.
|
14:00 |
3485. |
MR-Elastography, a new
biomarker of the tumor vascularization in a colon cancer
mice model
Lauriane Jugé1, Bich-Thuy Doan2,
Johanne Seguin2, Miguel Albuquerque1,
Benoit Larrat3, Daniel Scherman2,
Valerie Vilgrain1, Valérie Paradis1,
Bernard E. Van-Beers1, and Ralph Sinkus1
1CRB3 / UMR 773, CLICHY, Ile de France,
France, Metropolitan, 2UMR
8151, Unité de pharmacologie chimique et génétique et
d’Imagerie, -UPCGI/Chimie-Paristech, Paris, France,
Metropolitan, 3Institut
Langevin, ESPCI, Paris, France, Metropolitan
Assessment and follow-up of angiogenesis are major
challenges in cancer. We studied the alterations of the
vascularization during the spontaneous growth of a
murine colon tumor and after a treatment with an
antivascular agent. We obtained T2-weighted, 3D
steady-state MR-Elastography and Diffusion MR images.
After the MR examinations, the tumors were excised for
histological analysis (CD31 and KI67 immunohistology).
Our results show that it was possible to follow the
evolution of a tumor and the efficacy of an antivascular
agent using MRE. It was also shown that the viscosity
and the elasticity are potentially new biomarkers to
trace alterations of the vascularization.
|
14:30 |
3486. |
Measuring the Transient
before Steady-State in Brain MR Elastography ![](play.gif)
Curtis L Johnson1, Bradley P Sutton2,3,
and John G Georgiadis1,3
1Department of Mechanical Science and
Engineering, University of Illinois at Urbana-Champaign,
Urbana, IL, United States, 2Department
of Bioengineering, University of Illinois at
Urbana-Champaign, Urbana, IL, United States, 3Beckman
Institute for Advanced Science and Technology,
University of Illinois at Urbana-Champaign, Urbana, IL,
United States
The time required for shear waves to reach steady state
in Magnetic Resonance Elastography (MRE) of the brain is
investigated. The temporal evolution of the in-plane
displacement field of the brain was determined by
employing SPAMM tagging with HARP processing during the
typical head vibration used in MRE. Proper orthogonal
decomposition of this field is then used to determine
the time required for the brain to reach steady state.
This information is of use to brain MRE practitioners
for optimizing the actuation and acquisition method.
|
15:00 |
3487. |
Hydraulic conductivity
estimation using magnetic resonance elastography ![](play.gif)
Adam J Pattison1, Phillip R Perrinez1,
Matthew D.J. McGarry1, John B Weaver1,2,
and Keith D Paulsen1,3
1Thayer School of Engineering, Dartmouth
College, Hanover, New Hampshire, United States, 2Dartmouth-Hitchcock
Medical Center, Lebanon, New Hampshire, United States, 3Norris
Cotton Cancer Center, Lebanon, New Hampshire, United
States
While linear elastic and viscoelastic material models
are the norm for magnetic resonance elastography (MRE),
poroelasticity may better estimate properties of
biphasic material like brain tissue. Further, this
algorithm allows for estimation of hydrodynamic material
parameters such as pore pressure, porosity, and
hydraulic conductivity. Defined as the rate at which
fluid penetrates through pores, hydraulic conductivity
may provide new clinical information like
differentiation between normal and tumorous tissues and
detection of increased intracranial pressure. In a
recently developed poroelastic algorithm, this parameter
can be estimated with high accuracy and resolution in
simulated phantoms and may become an important biomarker
in disease processes.
|
Wednesday May 11th
|
13:30 - 15:30 |
Computer 47 |
13:30 |
3488. |
Quantitative Measurement
of Brain Deformation Caused by Pressure Loading of the Skull ![](play.gif)
Erik H. Clayton1, Agus Priatna2,
Bradley D Bolster, Jr.3, and Philip V Bayly1,4
1Mechanical Engineering & Material Science,
Washington University in St. Louis, St. Louis, MO,
United States, 2MR
R&D Collaborations, Siemens Healthcare, St. Louis, MO,
United States, 3MR
R&D Collaborations, Siemens Healthcare, Rochester, MN,
United States, 4Biomedical
Engineering, Washington University, St. Louis, MO,
United States
Traumatic brain injuries (TBI) are common and often lead
to permanent cognitive impairment, yet the condition
remains poorly understood. Computer simulations of
injury mechanics offer enormous potential for the study
of TBI; however, they require accurate experimental data
for validation. In this study, Magnetic Resonance
Elastography (MRE) imaging is used to measure brain
tissue motion for the purposes of calculating strains
imposed by acoustic extra-cranial pressure loading at 45
60, & 80 Hz. The unique features of this study are
knowledge of the external loading (pressure amplitude)
and the quantification of the brain’s response in terms
of mechanical strain.
|
14:00 |
3489. |
Whole brain MRE with
guided pressure waves
Xavier Maitre1, Emeline Lamain1,
Ralph Sinkus2, Bruno Louis3, and
Luc Darrasse1
1IR4M (UMR8081), Univ Paris-Sud, CNRS, Orsay,
France, 2Centre
de Recherches Biomedicales Bichat-Beaujon (UMR773),
CRB3, Inserm, Paris, France, 3Biomecanique
Cellulaire et Respiratoire (U841), IMRB, Inserm,
Creteil, France
For a given acquisition sequence, the sensitivity of
MR-elastography relies on the strength of the shear
waves which may be induced in the targeted organ. For
the last ten years, the brain has proven to be rather
well decoupled from any mechanical excitations by the
natural shielding layers. A very different approach from
current devices was taken here. By guiding pressure
waves into the buccal cavity, it was possible to
generate, throughout the brain, shear waves in the three
directions such that whole brain MRE could be performed
and 3D maps of dynamic and loss shear moduli could be
reconstructed.
|
14:30 |
3490. |
Non-Contact Driver System
for MR Elastography of the Breast ![](play.gif)
Jun Chen1, Kevin J Glaser1, Eric G
Stinson1, Jennifer L Kugel1, and
Richard L Ehman1
1Mayo Clinic, Rochester, MN, United States
Used in combination with dynamic CE-MRI, MRE has shown
promising results for characterizing breast disease.
Previously described MRE drivers contact the breasts
directly for wave transmission into the breasts, with
several disadvantages: (1) deforming the breasts; (2)
the variability in mechanical coupling, depending on
breast size; (3) requiring modification of the breast RF
coil; (4) interfering with MRI-guided breast biopsy.
This study evaluated an indirect-contact breast driver
that does not require direct breast contact and can be
used with any breast coil. The results demonstrated
shear wave illumination of breast tissue equivalent to
or better than existing drivers.
|
15:00 |
3491. |
Modeling Strain-Encoded
(SENC) MRI for Use in Clinical Breast Imaging ![](play.gif)
Ahmed Amr Harouni1, Nael F Osman2,
and Michael A Jacobs3
1Electrical and Computer Engineering, Johns
Hopkins University, Baltimore, Maryland, United States, 2Department
of Radiology, Johns Hopkins University, Baltimore,
Maryland, United States, 3Department
of Radiology and Oncology, Johns Hopkins University
school of medicine, Baltimore, Maryland, United States
Previously, we proposed using mass stiffness to increase
specificity of breast cancer detection using MRI. We
used strain-Encoded (SENC) MRI to measure strain, which
is inversely proportional to stiffness. However, since
SENC was originally developed for cardiac applications,
30% compression was used. In this work, we investigate
the minimum compression required to apply in order to
detect and classify breast masses through finite element
method simulations and phantom experiments. Our results,
shows that we can detect masses with low compressions
(5-10%), but in order to classify benign from malignant
masses we need to use higher compression (10-15%).
|
Thursday May 12th
|
13:30 - 15:30 |
Computer 47 |
13:30 |
3492. |
Feasibility of brain
MR-Elastography at 1.5 T with a novel wave generator: An
animal study ![](play.gif)
Najat Salameh1, Line Souris1,
Mathieu Sarracanie1, Ludovic de Rochefort1,
Ralph Sinkus2, Luc Darrasse1, and
Xavier Maître1
1IR4M (UMR 8081), Université Paris-Sud 11,
Orsay, France, 2Inserm
U979 - CNRS (UMR 7587), Institut Langevin, Paris, France
Protected by the meninges and the skull, the brain is a
challenging organ for Magnetic Resonance Elastography.
The challenge persists in rodents despite the smaller
dimensions since waves with higher frequencies and lower
penetration depth must be accordingly applied to resolve
the animal brain structures. In the present study, a new
excitation mode, where pressure waves are directly
guided into the animal mouth, is proposed. Proof of
concept and optimization of the technique were carried
out onto gel phantoms at 1.5 T. In vivo rat brain MRE
was then performed.
|
14:00 |
3493. |
A Novel Cardiac Phantom to
Study Murine and Human Cardiac Motion and Function using MRI ![](play.gif)
Christakis Constantinides1, Dimitris Nearchou1,
Christoforos Constantinou1, Panayiotis
Ktorides1, Robert Gravett2, and
Vasilios Tzagarakis3
1Mechanical and Manufacturing Engineering,
University of Cyprus, Nicosia, Cyprus, 2Shelley
Medical Imaging Technologies, London, Ontario, Canada, 3Alpha
Evresis Diagnostic Center, Nicosia, Cyprus
A novel cardiac MRI phantom is presented. Such phantom
is scalable to both the human and mouse hearts and can
be used in low and high field MRI systems. It
constitutes the technological platform for detailed
ex-vivo electro-mechanical studies of the cardiovascular
system at the tissue and organ levels in mice and
humans.
|
14:30 |
3494. |
Measurement of Ferret
Brain Tissue Stiffness in
vivo Using MR
Elastography ![](play.gif)
Yulin V Chang1, Yuan Aaron Feng1,
Erik H Clayton1, and Philip V Bayly1
1Mechanical Engineering, Washington
University, St. Louis, MO, United States
We present our initial experience of measuring brain
tissue stiffness in adult ferrets at several frequencies
using MR elastography. The average dynamics storage
modulus of the ferret brain is measured to be 3.6 ± 1.3
kPa at 400 Hz. Our results suggest that the ferret brain
appears to be slightly stiffer than the mouse brain and
softer than brain measured at similar frequencies. We
also observed frequency dependence of the brain tissue
stiffness in the ferret.
|
15:00 |
3495. |
Single-shot cardiac MR
Elastography ![](play.gif)
Sebastian Hirsch1, Thomas Elgeti1,
Dieter Klatt1, Juergen Braun2, and
Ingolf Sack1
1Department of Radiology, Charité -
University Medicine Berlin, Berlin, Germany, 2Institute
of Medical Informatics, Charité - University Medicine
Berlin, Berlin, Germany
A single-shot echo-planar imaging (EPI) cardiac MRE
technique is introduced which provides harmonic
displacement images of the heart within 20 to 70 ms
acquisition time depending on the desired motion
sensitivity and image resolution. This method allows one
to study multiple effects of wave dynamics in confined
media with time-varying elastic and geometrical
properties. Single-shot EPI-MRE facilitates
time-resolved evaluation of wave amplitudes as a
possible marker for myocardial dysfunction.
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|
Electronic
Posters
: Other
|
Click on
to view the abstract pdf and click on
to view the video presentation. |
Non-Proton MRI
Monday May 9th
Exhibition Hall |
14:00 - 16:00 |
Computer 48 |
14:00 |
3496. |
Visualization and
quantification of intestinal transit and motor function
by real-time tracking of 19F labeled capsules in humans ![](play.gif)
Tobias Hahn1, Sebastian Kozerke1,
Werner Schwizer2, Michael Fried2,
Peter Boesiger1, and Andreas Steingoetter1,2
1Institute for Biomedical Engineering,
University and ETH Zurich, Zurich, Switzerland, 2Division
of Gastroenterology and Hepatology, University
Hospital Zurich, Zurich, Switzerland
A combined 19F and 1H MRI framework enabling the
co-registration of local intestinal motor function
and transit assessed by 19F MRI with anatomical 1H
MRI data was implemented and its potential for
physiological GI MRI demonstrated. Biologically
inert and impermeable 15C5 labeled capsules were
developed. Capsule movement and gastric transit upon
oral administration of one and two capsules were
monitored in real time by a 19F projection imaging
sequence using a 3T whole-body system equipped with
a dual-channel 19F transmit-receive surface coil.
The developed framework was found to be feasible for
the non-invasive visualization and quantification of
gastrointestinal motor activity.
|
14:30 |
3497. |
In vivo
gastrointestinal transit study using double-labelled
markers ![](play.gif)
Elisa Placidi1, Caroline L Hoad1,
Luca Marciani2, Alan C Perkins3,
P E Blackshaw3, Robin C Spiller2,
and Penny A Gowland1
1SPMMRC, Nottingham, Nottinghamshire,
United Kingdom, 2Nottingham
Digestive Diseases Centre Biomedical Research Unit,
Nottingham, United Kingdom, 3Academic
Medical Physics, Nottingham, United Kingdom
A pilot in vivo study measuring gastrointestinal
transit with MRI is presented. Purpose built plastic
capsules, double labelled with a fluorine agent and
a gadolinium solution were given to two volunteers
scanned up to 48 hours. The Gadolinium solution gave
a very bright signal which could be identified at
all time points in the entire GI tract. The fluorine
image gave confirmation of their position but the
fluorine coil often had to be repositioned after the
exact location of the capsules was established. In
future it will be possible to perform studies of GI
transit using just 1H labelled capsules.
|
15:00 |
3498. |
19F-MRI: Flow
Measurement of Fluorinated Gases During High Frequency
Oscillatory Ventilation
Janet Friedrich1, Julien Rivoire1,
Maxim Terekhov1, and Laura Maria
Schreiber1
1Section of Medical Physics, Johannes
Gutenberg University Medical Center, Mainz, Germany
High frequency oscillatory ventilation (HFOV) is a
protective ventilation method mainly used for
patients with acute respiratory distress syndrome
(ARDS). To explore gas flow mechanisms during HFOV
19F-MRI of fluorinated gases was performed at 1.5T.
With a flow sensitive gradient-echo-sequence
velocity profiles during HFOV could be determined
and tracked over time with a temporal resolution of
10ms. The signal-to-noise ratio and hence the
reliability of velocity information could be
improved by skipping the phase encoding gradient. In
summary, the present work demonstrates that flow
measurement of fluorinated gases is feasible and can
also be applied under HFOV.
|
15:30 |
3499. |
Feasibility of in vivo
phosphorus imaging of cortical bone at 7T in humans ![](play.gif)
Ping-Huei Tsai1, Alan C Seifert1,
Alexander C Wright1, Hamidreza S Rad1,
Jeremy F Magland1, Hee Kwon Song1,
Mary B Leonard2, and Felix W Wehrli1
1Laboratory for Structural NMR Imaging,
Department of Radiology, University of Pennsylvania,
Philadelphia, PA, United States, 2Center
for Clinical Epidemiology and Biostatistics,
Children¡¦s Hospital of Philadelphia, Philadelphia,
PA, United States
Osteomalacia is characterized by hypomineralization
of bone, i.e., low phosphorus concentration, and a
noninvasive means to assess bone phosphorus would be
desirable. However, 31P MR signals from bone have
low SNR due to extremely short T2* and long T1, as
well as small gyromagnetic ratio. High-field
scanners and 3D radial imaging sequences can
mitigate these limitations. The purpose of this
study was to design and evaluate the peformance a 3D
radial imaging technique and customized RF coils to
obtain in-vivo phosphorus images of human cortical
bone at the mid-shaft tibia at 7T. Preliminary
results demonstrate the method¡¦s feasibility and
suggest the potential for quantitative measurements.
|
Tuesday May 10th
|
13:30 - 15:30 |
Computer 48 |
13:30 |
3500. |
Development of
dual-tuned knee coil at 7T: a feasibility study of
high-resolution sodium MR imaging and T2 mapping in knee
cartilage in vivo ![](play.gif)
Junghwan Kim1, Bumwoo Park1,
Alessandro Furlan1, Chanhong Moon1,
Sung-hong Park1, Tiejun Zhao2,
and Kyongtae Ty Bae1
1Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, United States, 2MR
Research Support, Siemens Healthcare, Pittsburgh,
PA, United States
We have developed a dual-tuned proton/sodium knee RF
coil at 7T and obtained high-resolution sodium MR
imaging and T2 mapping of human knee cartilages
within clinically acceptable time. Further studies
on coil optimization and reproducibility of sodium
concentration measurement should be followed for the
clinic application.
|
14:00 |
3501. |
A triple-resonant coil
system for inherently co-registered proton-, sodium- and
chloride-MRI at 9.4T
Friedrich Wetterling1, Saema Ansar2,
Laurant Tritschler2, Raffi Kalayciyan1,
Stefan Kirsch1, Marc Fatar2,
Stephen Meairs2, and Lothar R. Schad1
1Computer Assisted Clinical Medicine,
Heidelberg University, Mannheim, Germany, 2Departmenet
of Neuroloy, Heidelberg University, Mannheim,
Germany
The aim of this project was to develop a triple
resonant 1H/23Na/35Cl coil system for investigations
on a rat stroke model without the need to exchange
resonators during the measurements. The
newly-developed coil system was composed of a linear
1H birdcage resonator and a double-tuned 35Cl/23Na
surface coil. 1H imaging capability enabled the use
of standard stroke sequences such as diffusion- and
T2 weighted MRI. The coil performance was
successfully tested on a 1H/35Cl/23Na-phantom. First
brain images at 5 days after stroke confirmed the
excellent coil performance for in vivo imaging.
|
14:30 |
3502. |
Evaluation of
B0-Inhomogeneity Correction for Triple-Quantum-Filtered
Sodium MRI of the Human Brain at 4.7T ![](play.gif)
Adrian Tsang1, Rob Stobbe1,
and Christian Beaulieu1
1Biomedical Engineering, University of
Alberta, Edmonton, Alberta, Canada
B0-inhomogeneities may cause regional signal loss on
triple-quantum-filtered (TQF) sodium images. Three
phase cycling algorithms were proposed recently to
rectify this adverse effect with the cost of
extensively increasing scan time; however, these
were all only verified on small agarose phantoms.
The goal of our study is to evaluate the extent of
off resonance signal loss and their correction on
human brain sodium TQF images and to determine
whether the considerable two fold increase in scan
time is warranted for in vivo studies.
|
15:00 |
3503. |
Rodent Glioma
Chemotherapy and Sodium MRI at 21.1T ![](play.gif)
Victor D. Schepkin1, Fabian Calixto
Bejarano1, Thomas Morgan2,
Shannon Gower-Winter2, and Cathy W.
Levenson2
1CIMAR/MRI, NHMFL/FSU, Tallahassee,
Florida, United States, 2Biomedical
Sciences, FSU, Tallahassee, Florida, United States
The diagnostic value of sodium MRI has not been
established; however, the evidence of its potential
is growing with the availability of high magnetic
fields. Rodent glioma therapy by BCNU was thoroughly
evaluated by sodium and diffusion MRI. The time
courses of tumor responses reveal loss of the
tumors’ intracellular sodium gradients early on
during therapy, demonstrating it can be part of the
in vivo apoptotic process. This finding correlates
with multiple evidences already found in vitro. The
effect of positive therapy can be detected for each
animal individually in a day after initiation of
treatment.
|
Wednesday May 11th
|
13:30 - 15:30 |
Computer 48 |
13:30 |
3504. |
In Vivo Brain Sodium
T2* Mapping with a Multiple-echo Flexible TPI Sequence ![](play.gif)
Aiming Lu1, Ian C Atkinson1,
and Keith R Thulborn1
1Center for MR Research, University of
Illinois, Chicago, IL, United States
The sodium MR signal is affected by the local
electrical field gradient and exhibits
bi-exponential relaxation behavior in brain. The
relaxation times not only are critical parameters
for optimizing the sequences for quantifying tissue
sodium concentration, but also convey information on
the local sodium ion environment. However mapping
the relaxation times of sodium in biological tissues
in vivo is challenging. We demonstrate here with an
efficient multiple-echo flexible twisted projection
imaging sequence that high quality T2* maps of the
sodium MR signal in the entire human brain can be
achieved within a reasonable scan time at 3T.
|
14:00 |
3505. |
Sodium Relaxation
Times in the Knee Joint In Vivo at 7T ![](play.gif)
Guillaume Madelin1, Alexej Jerschow2,
and Ravinder R Regatte1
1Radiology Department, New York
University Medical Center, New York, NY, United
States, 2Chemistry
Department, New York University, New York, NY,
United States
This preliminary work shows the feasibility of
sodium T1 and T2* measurements in vivo on 8 healthy
volunteers in 4 different regions (patellar, medial,
lateral and condyle) of the articular cartilage at
7T and in a reasonable time for the patient (~35 min
for each relaxation time). Sodium relaxation maps
are calculated and could be useful as information
complementary to the sodium concentration maps for
assessing early osteoarthritis (OA) in patients, as
T2* and T1 are expected to change with cartilage
degeneration. Future improvements may include fluid
suppression for reducing partial volume effects and
a systematic study of OA patients.
|
14:30 |
3506. |
In Vivo Breast Sodium
T1 Measurements Using Inversion Recovery 3D Cones ![](play.gif)
Joshua Kaggie1, Danny Park2,
Rexford D Newbould3, Glen R Morrell4,
Brian Hargreaves5, Ernesto Staroswiecki5,6,
Gary E Gold5, and Neal K Bangerter2
1Physics, University of Utah, Salt Lake
City, UT, United States, 2Electrical
& Computer Engineering, Brigham Young University,
Provo, UT, United States, 3GSK
Clinical Imaging Centre, London, United Kingdom, 4Radiology,
University of Utah, Salt Lake City, UT, United
States, 5Radiology,
Stanford, Stanford, CA, United States, 6Electrical
Engineering, Stanford, CA, UT, United States
In this work, we improve upon previously reported
values of T1 and T2* for sodium in the breast.
Previously, we used a DESPOT1 sequence, whereas we
have developed an inversion recovery sequence so
that we can measure T1 values more accurately. For
our healthy woman volunteer, we measured sodium T1
to be 39.0 ± 4.8 ms, T2long to be 21.0 ± 5.6 ms, and
T2short to be 0.8 ± 0.4 ms.
|
15:00 |
3507. |
Relaxation Time
Measurements of 31P
Metabolites in Human Muscle at 9.4 Tesla ![](play.gif)
Yi Sui1,2, Haoyang Xing2,
Theodore Claiborne2, Keith R Thulborn2,3,
and Xiaohong Joe Zhou2,4
1Department of Bioengineering, University
of Illinois at Chicago, Chicago, IL, United States, 2Center
for Magnetic Resonance Research, University of
Illinois Medical Center, Chicago, IL, United States, 3Department
of Radiology, University of Illinois Medical Center,
Chicago, IL, United States, 4Departments
of Radiology, Neurosurgery and Bioengineering,
University of Illinois Medical Center, Chicago, IL,
United States
In this study, we report multiple techniques to
address the challenges of 31P relaxation
measurements at 9.4 T. A Look-locker (LL) method was
adapted for T1 measurement to shorten the total scan
time. A two-tip-angle method was used to address the
B1-field non-uniformity problem in the LL sequence.
Additionally, quadratic-phase modulated RF pulses
were employed to reduce RF peak amplitude without
compromising the requirement of broad bandwidth of
31P spectrum at 9.4T. By strategically integrating
these techniques, 31P relaxation times in human
muscle have been determined accurately at 9.4 T
within ~30 min.
|
Thursday May 12th
|
13:30 - 15:30 |
Computer 48 |
13:30 |
3508. |
Quantitative Sodium
MRI with Fluid Suppression in the Knee Joint at 3T and
7T ![](play.gif)
Guillaume Madelin1, Gregory Chang1,
Alexej Jerschow2, and Ravinder R Regatte1
1Radiology Department, New York
University Medical Center, New York, NY, United
States, 2Chemistry
Department, New York University, New York, NY,
United States
This study demonstrates the feasibility of
quantitative sodium MRI with fluid suppression in
vivo in the knee joint at 3T and compares the
results with that of 7T on the same 4 asymptomatic
healthy volunteers. Two inversion recovery based
methods (with a rectangular and an adiabatic pulse)
for suppressing the fluids are also compared and
show a good agreement at both fields. These
preliminary results at 3T, despite their lower SNR
and the small number of volunteers in this study,
show slightly lower sodium concentration
measurements but are still in good agreement with
the data at 7T.
|
14:00 |
3509. |
High Resolution Sodium
MRI on Human Brain at 7T ![](play.gif)
Yongxian Qian1, Tiejun Zhao2,
Jonathan Weimer3, Hai Zheng3,
and Fernando E Boada1,3
1Radiology, University of Pittsburgh,
Pittsburgh, PA, United States, 2R&D,
Siemens Medical Solutions USA, Pittsburgh, PA,
United States, 3Bioengineering,
University of Pittsburgh, Pittsburgh, PA, United
States
The 7T scanners produce images of higher signal to
noise ratio (SNR) than the 3T scanners and thus have
potential to generate sodium images of higher
spatial resolutions. This work demonstrates the
feasibility of high-resolution (0.86mm) sodium
imaging on human brain at 7T.
|
14:30 |
3510. |
Sub-millimeter 23Na
Imaging in Human Calf Skin at 7.0T ![](play.gif)
Peter Linz1, Davide Santoro2,
Wolfgang Renz2,3, Jan Ruff3,
Jens Titze4, Friedrich Luft5,
and Thoralf Niendorf2,5
1Department of Nephrology and
Hypertension, University Clinic Erlangen-Nuernberg,
Erlangen, Germany, 2Berlin
Ultrahigh Field Facility, Max-Delbrueck Center for
Molecular Medicine, Berlin, Germany, 3Siemens
Healthcare, Erlangen, Germany, 4Department
of Nephrology and Hypertension and
Nikolaus-Fiebiger-Center for Molecular Medicine,
University Clinic Erlangen-Nuernberg, Erlangen,
Germany, 5Experimental
and Clinical Research Center (ECRC), Charité Campus
Buch, Humboldt-University, Berlin, Germany
We propose a dedicated 23Na coil to accomplish the
first 23Na-MRI images of the skin with a
sub-millimeter in plane resolution.
|
15:00 |
3511. |
RARE imaging of
post-exercise phospocreatine recovery - validation and
reproducibility ![](play.gif)
Robert L. Greenman1, Xiaoen Wang1,
and Howard A. Smithline2
1Radiology, Beth Israel Deaconess Medical
Center/Harvard Medical School, Boston, MA, United
States, 2Emergency
Medicine, Bay State Medical Center, Tufts University
School of Medicine, Boston and Springfield, MA,
United States
The structure, blood flow patterns and metabolism
have wide spatial variations in healthy individuals
and are further modified in disease states and with
physical training. Current methods cannot provide a
simultaneous assessment of multiple muscle beds in a
human limb. To address this need we have evaluated a
phosphorus-31 MRI method for measuring the
post-exercise recovery time constant of
phosphocreatine in all of the muscles in a
cross-section of the human leg. The method agrees
very closely with the current standard method of
phosphorus-31 MR spectroscopy and is highly
reproducible.
|
|
|
Electronic
Posters
: Other
|
Click on
to view the abstract pdf and click on
to view the video presentation. |
Hyperpolarized C13 I
Monday May 9th
Exhibition Hall |
14:00 - 16:00 |
Computer 49 |
14:00 |
3512. |
Metabolism of
Hyperpolarized [1-13C]Pyruvate in Isolated
Perfused Mouse Livers – A Comparison of Fed and Fasted
States ![](play.gif)
Benjamin M. Pullinger1, Stephen J.
Kadlecek1, Helen Chen2,
Qingwei Chu2, Nicholas N. Kuzma1,
and Rahim R. Rizi1
1Radiology, University of Pennsylvania,
Philadelphia, PA, United States, 2Department
of Biochemistry and Biophysics, University of
Pennsylvania, Philadelphia, PA, United States
The metabolism of hyperpolarized [1- 13C]pyruvate
was investigated in the isolated perfused mouse
liver. Along with the commonly observed conversions
to alanine and lactate, we also observed pyruvate
dehydrogenase (PDH) and pyruvate carboxylase (PC)
activity. The ability to simultaneously measure PC
and PDH flux has important implications in the study
of insulin resistance. As a proof of concept, we
report an increase in PC flux (0.17 0.03
to 0.30 0.06)
in fasted livers compared to fed livers.
|
14:30 |
3513. |
Detection of acute
kidney injury using hyperpolarized [1,4-13C2]fumarate
Mikko I Kettunen1, Menna R Clatworthy2,3,
Timothy H Witney1, De-en Hu1,
Brett W. C Kennedy1, Sarah E Bohndiek1,
Rebeccah J Mathews2,3, Ferdia A Gallagher1,4,
Ken G Smith2,3, and Kevin M Brindle1
1Department of Biochemistry, University
of Cambridge & Cancer Research UK Cambridge Research
Institute, Cambridge, Cambridgeshire, United
Kingdom, 2Cambridge
Institute for Medical Research, Cambridge,
Cambridgeshire, United Kingdom, 3Department
of Medicine, University of Cambridge School of
Clinical Medicine, Cambridge, Cambridgeshire, United
Kingdom, 4Department
of Radiology, Addenbrooke’s Hospital, University of
Cambridge, Cambridge, Cambridgeshire, United Kingdom
Acute tubular necrosis (ATN) and glomerulonephritis
(GN) are two common clinical forms of acute kidney
injury with different treatment requirements.
Currently, there is no non-invasive test to
differentiate them. Here we exploited the appearance
of malate signals following injection of
hyperpolarized [1,4-13C2]fumarate
to identify folate-induced ATN. Significantly
increased malate signals were observed 18h after
folate injection indicating increased necrosis. In
contrast, malate signals were not increased in GN
model despite the presence of proteinuria in both
models. The results suggest hyperpolarized [1,4-13C2]fumarate
is a potential non-invasive marker for separating
ATN and GN.
|
15:00 |
3514. |
Chemical Shift
Selective Imaging of Hyperpolarized 13C
Using Variable Phase Balanced Steady-State Free
Precession ![](play.gif)
Aaron Keith Grant1, Elena Vinogradov1,
Xiaoen Wang1, Hao Wang1,
Pankaj K Seth2, Vikas P Sukhatme2,
David C Alsop1, and Robert E Lenkinski1
1Radiology, Beth Israel Deaconess Medical
Center and Harvard Medical School, Boston, MA,
United States, 2Medicine,
Beth Israel Deaconess Medical Center and Harvard
Medical School, Boston, MA, United States
13C spectra acquired after administration of
hyperpolarized contrast media generally result in a
relatively sparse collection of spectra lines.
Several strategies that exploit this sparsity have
been proposed for fast 13C spectroscopic imaging.
Here we show that by acquiring a series of balanced
steady-state free precession (bSSFP) images with a
variable RF phase advance it is possible to obtain
separate images of several metabolites. The method
is illustrated using phantoms and in vivo studies
with hyperpolarized pyruvate and t-butanol.
|
15:30 |
3515. |
Super Stimulated-Echo
Preparation for Hyperpolarized 13C Metabolic Imaging ![](play.gif)
Peder Eric Zufall Larson1, Adam B Kerr2,
Ralph E Hurd3, John Kurhanewicz1,
John M Pauly2, and Daniel B Vigneron1
1Radiology and Biomedical Imaging, UC -
San Francisco, San Francisco, CA, United States, 2Electrical
Engineering, Stanford University, Stanford, CA,
United States,3Applied Science
Laboratory, GE Healthcare, Menlo Park, CA, United
States
Stimulated-echoes can be used to provide high
sensitivity to diffusion and flow, creating unique
contrast, but they inherently suffer from a 50%
signal loss. The signal can be improved with a super
stimulated-echo, which is more efficient. We have
designed a new super stimulated-echo preparation
scheme for diffusion and perfusion contrast in
hyperpolarized 13C metabolic imaging. These have an
expected 60% increase in SNR over a conventional
stimulated-echo. By utilizing adiabatic pulse shapes
in the preparation, they also have an improved
response to B1+ variations. In vivo experiments in
transgenic cancer mouse models have shown improved
contrast for tumors.
|
Tuesday May 10th
|
13:30 - 15:30 |
Computer 49 |
13:30 |
3516. |
Transient decrease in
tumor pO2 by 13C-pyruvate
injection ![](play.gif)
Keita Saito1, Shingo Matsumoto1,
Nallathamby Devasahayam1, Sankaran
Subramanian1, Jeeva P Munasinghe2,
Jan Henrik Ardenkjaer-Larsen3, Herman
Douglas Morris2, Martin J Lizak2,
James B Mitchell1, and Murali C Krishna1
1National Cancer Institute, Bethesda,
Maryland, United States, 2National
Institute of Neurological Disorder and Stroke, 3GE
Healthcare
MRI using hyperpolarized [1-13C]pyruvate
is a promising tool for cancer diagnosis, but
influences of exogenously injected pyruvate on tumor
physiology were not well understood. Here, effects
of pyruvate injection on tumor oxygen status were
investigated using pulsed electron paramagnetic
resonance imaging. Tumor pO2 was
remarkably decreased 30 min after [1-13C]pyruvate
injection. The pO2 decrease
was transient, and the pO2 recovered
to the pre-injection level 5 h after the pyruvate
injection. This transient decrease in the pO2 influenced
effects of X-irradiation: tumor growth suppression
by X-irradiation was weakened when [1-13C]pyruvate
was injected to mice 30 min before X-irradiation.
|
14:00 |
3517. |
Metabolic Kinetics of
a Glioma Model Using Hyperpolarized 13C Magnetic
Resonance Spectroscopic Imaging ![](play.gif)
Jae Mo Park1,2, Sonal Josan2,3,
Taichang Jang4, Milton Merchant4,
Yi-fen Yen5, Ralph Hurd5,
Lawrence Recht4, Daniel Spielman1,2,
and Dirk Mayer2,3
1Department of Electrical Engineering,
Stanford University, Stanford, CA, United States, 2Department
of Radiology, Stanford University, Stanford, CA,
United States, 3SRI
International, Menlo Park, CA, United States, 4Department
of Neurology and Neurological Sciences, Stanford
University, Stanford, CA, United States, 5Global
Applied Science Laboratory, GE Healthcare, Menlo
Park, CA, United States
In this work, we measured the kinetics of pyruvate
metabolism in a glioma brain tumor model using the
hyperpolarized 13C technique with a fast spiral CSI
sequence, and compared the metabolic kinetics from
three different ROIs: brain tumor, normal brain, and
vasculature. Robust dynamic curves of Pyr and Lac
were achievable repeatedly with 3 seconds of
temporal resolution using the variable RF excitation
angle on a single slice. The apparent rate constant
of Pyr-to-Lac conversion in the brain tumor was
noticeably higher than that in the normal brain and
the vasculature.
|
14:30 |
3518. |
Construction and Use
of a Cryostat for Hyperpolarization Based on a 15 cm,
4.6 T Magnet ![](play.gif)
Lloyd Lumata1, Richard Martin1,
Ashish Jindal2, Zoltan Kovacs1,
Craig Malloy1, A Dean Sherry1,
Mark Conradi3, and Matthew E Merritt1
1AIRC, UTSW Medical Center, Dallas, TX,
United States, 2UTSW
Medical Center, United States, 3Physics,
Washington University in St. Louis, St. Louis, MO,
United States
In order to produce large volumes of highly
polarized imaging agents, a DNP system based on a
cryostat placed in an ultra widebore 4.6 T magent
has been designed and implemented. The large
available space allows a 600 ul sample cup to be
used as well as an LN2 shield for the LHe bath.
Operating at a 129 GHz ESR frequency and using
nitrogen based radicals, samples with sufficient
polarization for animal imaging are easily obtained.
Total cost of the system was less than $100K, sans
the cost of the magnet.
|
15:00 |
3519. |
Fast volumetric
imaging of ethanol metabolism in rat with hyperpolarized
[1-13C]-pyruvate ![](play.gif)
Sonal Josan1,2, Daniel Spielman2,
Yi-Fen Yen3, Ralph Hurd3,
Adolf Pfefferbaum1,4, and Dirk Mayer1,2
1SRI International, Menlo Park, CA,
United States, 2Radiology,
Stanford University, Stanford, CA, United States, 3GE
Healthcare Applied Science Laboratory, Menlo Park,
CA, United States, 4Psychiatry
and Behavioral Sciences, Stanford University,
Stanford, CA, United States
This work demonstrates time-resolved volumetric
metabolic imaging of hyperpolarized [1-13C]-pyruvate
using an undersampled spiral MRSI sequence, and
applies it to investigate Pyr metabolism modulated
by ethanol in rat liver. The dynamic 3D acquisition
allows the analysis of spectra from organ-specific
regions-of-interest, thus providing improved
rate-constant estimates. Ethanol metabolism in the
liver leads to accumulation of NADH which is a
coenzyme in Pyr-to-Lac conversion. The apparent
liver Pyr-to-Lac rate constants increased from pre-
to post-ethanol, confirming the hypothesis that NADH
levels are rate-limiting for liver Pyr-to-Lac
conversion.
|
Wednesday May 11th
|
13:30 - 15:30 |
Computer 49 |
13:30 |
3520. |
Simultaneous
Bloch-Siegert B1 mapping
and imaging of hyperpolarized pyruvate, bicarbonate, and
lactate, in a single tracer bolus ![](play.gif)
Angus Zoen Lau1,2, Albert P Chen3,
and Charles H Cunningham1,2
1Medical Biophysics, University of
Toronto, Toronto, ON, Canada, 2Imaging
Research, Sunnybrook Health Sciences Centre,
Toronto, ON, Canada, 3GE
Healthcare, Toronto, ON, Canada
Precise determination of transmit RF power (B1+)
for 13C
MR is challenging due to limited natural abundance
of 13C
in vivo. The phase-based Bloch-Siegert shift
provides a B1 mapping
method independent of Mz, making it
possible to encode B1 in
an image of hyperpolarized magnetization.
Bloch-Siegert B1 mapping
was implemented in a multi-slice interleaved 13C
imaging pulse sequence. This study demonstrated the
feasibility of simultaneously acquiring a B1 map and
images of hyperpolarized [1-13C]pyruvate,13C
bicarbonate, and [1-13C]lactate following
a single tracer bolus of pre-polarized [1-13C]pyruvate
and is anticipated to provide improved quantitative
measurements of13C metabolism in vivo.
|
14:00 |
3521. |
Investigating the Role
of PDH Inhibition on the Development of Hypertrophy in
the Hyperthyroid Rat Heart ![](play.gif)
Helen J Atherton1,2, Michael S Dodd1,
Lisa C Heather1, Marie A Schroeder1,
Julian L Griffin2, George K Radda1,
Kieran Clarke1, and Damian J Tyler1
1Department of Physiology, Anatomy &
Genetics, University of Oxford, Oxford, United
Kingdom, 2Department
of Biochemistry, University of Cambridge, Cambridge,
United Kingdom
Hyperthyroidism, caused by an elevated level of
thyroid hormones, leads to an increase in heart
rate, contractility and cardiac output. Cardiac
hypertrophy is another effect of hyperthyroidism
and, although the hypertrophy is initially
beneficial, it can lead to heart failure. The aim of
this work was to determine whether alleviating the
known inhibition of pyruvate dehydrogenase (PDH) in
the hyperthyroid heart using dichloroacetate (DCA)
would affect the response to hyperthyroidism. Using
hyperpolarized MRS and CINE MRI, we found that DCA
treatment increased PDH flux by 134% and
significantly reduced the level of hypertrophy
observed in the hyperthyroid rat heart.
|
14:30 |
3522. |
Method for robust pH
measurement using hyperpolarized bicarbonate and carbon
dioxide ![](play.gif)
Albert P Chen1, Ralph E Hurd2,
Marie A Schroeder3,4, Angus Z Lau4,5,
Yi-Ping Gu4, Wilfred W Lam4,
and Charles H Cunningham4,5
1GE Healthcare, Toronto, ON, Canada, 2GE
Healthcare, Menlo Park, CA, United States, 3Department
of Physiology, Anatomy and Genetics, University of
Oxford, Oxford, United Kingdom, 4Imaging
Research, Sunnybrook Health Sciences Centre,
Toronto, ON, Canada, 5Deptartment
of Medical Biophysics, University of Toronto,
Toronto, ON, Canada
To improve the robustness of pH measurement using
hyperpolarized H13CO3- and 13CO2 signals
in presence of carbonic anhydrase activity, the 13CO2 resonance
was excited independently with a chemically
selective RF pulse of larger tip-angle (to achieve
higher SNR), while the other resonances of interest
were acquired with a smaller tip angle. Accurate pH
measurement could still be obtained even with
repeated tipping (for temporally and/or spatially
resolved data), since the ratio between the two
pools was rapidly restored by the enzyme mediated
exchange. This method was demonstrated in phantom
and in
vivo in
pig heart.
|
15:00 |
3523. |
Spectroscopic Imaging
of Cerebral Metabolism using Hyperpolarized
[1-13C]Pyruvate and Multi-echo Single-shot RARE sequence
Peter Otto Magnusson1, Sadia Asghar Butt1,
Mette Hauge Lauritzen1, Jan Henrik
Ardenkjær-Larsen2, Per Åkesson1,
and Lise Vejby Søgaard1
1Danish Research Centre for Magnetic
Resonance, Copenhagen University Hospital Hvidovre,
Hvidovre, Denmark, 2GE
Healthcare, Hillerød, Denmark
Efficient and rapid utilization of available
magnetization is of greatest importance in
hyperpolarized 13C MR since the in vivo decay time
constant of the hyperpolarized signal is less than
one minute. Here we demonstrate the potential of a
multi-echo single-shot RARE sequence (FSEME) for
rapid spectroscopic imaging of cerebral metabolism
using HP [1-13C]Pyruvate. A FSEME-sequence was
implemented and optimized and in vivo rat head
13C-scanning was conducted. Identification of
cerebral sub-structures in metabolite maps from
hyperpolarized [1-13C]Pyruvate in the rat brain was
for the first time demonstrated using the rapid
FSEME spectroscopic imaging sequence.
|
Thursday May 12th
|
13:30 - 15:30 |
Computer 49 |
13:30 |
3524. |
Autophagy induced by
DCA treatment, PI3K inhibition or starvation results in
reduced pyruvate to lactate exchange observed by DNP
13C-MRS. ![](play.gif)
Yuen-Li Chung1, Gigin Lin1,
Helen Troy1, Anne-Christine Wong Te Fong1,
L E Jackson1, Deborah K Hill1,
Matthew Orton1, Dow-Mu Koh1,
Simon P Robinson1, Ian R Judson2,
John R Griffiths3, Martin O Leach1,
and Thomas R Eykyn1
1CR-UK & EPSRC Cancer Imaging Centre,
Institute of Cancer Research and Royal Marsden
Hospital, Sutton, Surrey, United Kingdom, 2CR-UK
Centre for Cancer Therapeutics, Institute of Cancer
Research and Royal Marsden Hospital, Sutton, Surrey,
United Kingdom, 3Li
Ka Shing Centre, CR-UK Cambridge Research Institute,
Cambridge, United Kingdom
Autophagy is a cellular degradation response to
starvation or stress whereby cellular proteins,
organelles and cytoplasm are engulfed, digested and
recycled to sustain cellular metabolism. We have
investigated the effects of autophagy on TCA cycle
activation using 1-13C-pyruvate DNP 13C-MRS.
Autophagy was induced in three cancer cell lines by
starvation, dichloroacetate and PI103 treatment. A
significant reduction in the rate of labelled
[1-13C] pyruvate to lactate exchange (and
unpolarised lactate production) was associated with
autophagy, rather than apoptosis or necrosis. A
reduction in lactate production as measured by DNP
13C-MRS, and unchanged NAD+, may provide a
non-invasive surrogate biomarker of autophagy.
|
14:00 |
3525. |
Investigating tumor
perfusion and metabolism using multiple hyperpolarized 13C
compounds: HP001, urea, and pyruvate ![](play.gif)
Cornelius von Morze1, Peder E Larson1,
Simon Hu1, Robert Bok1, Hikari
Yoshihara1, Andrei Goga2, Jan
Henrik Ardenkjaer-Larsen3, and Daniel B
Vigneron1
1Department of Radiology and Biomedical
Imaging, UCSF, San Francisco, CA, United States, 2Department
of Medicine, Division of Hematology / Oncology,
UCSF, San Francisco, CA, United States, 3GE
Healthcare, Hillerød, Denmark
The addition of perfusion information to metabolic
information obtained by spectroscopic imaging of
hyperpolarized [1-13C]pyruvate would be
of great value in exploring links between perfusion
and metabolism in cancer. We performed both dynamic
imaging of the perfusion compound HP001, and
co-polarized spectroscopic imaging of urea and
pyruvate in preclinical murine cancer models.
Spatially heterogenous perfusion was observed in the
tumor tissues. A correlation between the urea and
HP001 data confirmed the value of co-polarizing urea
with pyruvate for simultaneous assessment of
perfusion and metabolism.
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14:30 |
3526. |
Arterial input
function by DNP measurement using an automated injector
designed for a 7T unshielded magnet ![](play.gif)
Steven Reynolds1, Samira Kazan2,
Leigh Williams2, Aneurin Kennerley3,
Jason Berwick3, Gillian Tozer2,
and Martyn Paley1
1Academic unit of Radiology, Medical
school, University of Sheffield, Sheffield, S.
Yorkshire, United Kingdom, 2Department
of Oncology, Medical school, University of
Sheffield, Sheffield, S. Yorkshire, United Kingdom, 3Department
of Psychology, University of Sheffield, Sheffield,
S. Yorkshire, United Kingdom
Using the sensitivity enhancement of DNP we are
using hyperpolarised pyruvate as a biomarker for
changes in tumour oxygenation. To improve our model
of the pyruvate metabolic flux we have measured the
arterial input function (AIF) using the
hyperpolarised 13C pyruvate signal from the carotid
artery of a BDIX rat. Since AIF is dependent upon
the injection condition there was a requirement to
provide an automated, rapid, injection system. We
have developed an automated injector that can be
used close the bore of an unshielded 7T magnet.
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15:00 |
3527. |
Efficient preparation
of hyperpolarized aqueous succinate from the para-hydrogenation
and hydrolysis of maleic anhydride ![](play.gif)
Francesca Reineri1, Alessandra Viale1,
Silvano Ellena1, Tommaso Boi1,
Roberto Gobetto1, and Silvio Aime1
1University of Torino, Torino, IT, Italy
Para-Hydrogen Induced Polarization (PHIP) has been
recently exploited for the preparation of
hyperpolarized 13C
contrast agents for MRI. For the observation of
large PHIP effects the use of homogeneous
hydrogenation catalysts is generally required. The
catalyst and (if present) the organic solvent must
then be removed in order to obtain non-toxic
formulations of the hyperpolarized agents. Here we
report the para-hydrogenation of an unsaturated
activated substrate, maleic anhydride, in
chloroform, followed by rapid hydrolysis to form a
water-soluble derivative, succinic acid, which can
be extracted in water to yield a pure aqueous
solution of the hyperpolarized molecule.
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Click on
to view the abstract pdf and click on
to view the video presentation. |
Electronic
Posters
: Other
|
Hyperpolarized C13 II
Monday May 9th
Exhibition Hall |
14:00 - 16:00 |
Computer 50 |
14:00 |
3528. |
Effects of RF excitation
scheme on signal-to-noise-ratio and apparent rate constant
estimation in dynamic volumetric imaging of hyperpolarized
[1-13C]-pyruvate ![](play.gif)
Sonal Josan1,2, Ralph Hurd3, Adam
B Kerr4, Yi-Fen Yen3, Peder E.Z.
Larson5, Adolf Pfefferbaum1,6,
Daniel Spielman2, and Dirk Mayer1,2
1SRI International, Menlo Park, CA, United
States, 2Radiology,
Stanford University, Stanford, CA, United States, 3GE
Healthcare Applied Science Laboratory, Menlo Park, CA,
United States, 4Electrical
Engineering, Stanford University, Stanford, CA, United
States, 5Dept
of Radiology and Biomedical Imaging, UC-San Francisco,
San Francisco, CA, United States, 6Psychiatry
and Behavioral Sciences, Stanford University, Stanford,
CA, United States
Dynamic 3D metabolic imaging of hyperpolarized [1-13C]-pyruvate
requires a large number of RF excitations, which can
impact the shape of the dynamic response, the
calculation of apparent rate constants, and signal to
noise ratio. This work investigates the performance of
different flip angle schemes using multi-band RF pulses
in multiple organs (brain, liver and kidney) with
different tissue perfusion rates and metabolic
activities.
|
14:30 |
3529. |
Dynamic imaging of
hyperpolarized [2-13C] pyruvate and [5-13C]
glutamate in the heart ![](play.gif)
Angus Zoen Lau1,2, Albert P Chen3,
Marie A Schroeder4, Jennifer Barry2,
and Charles H Cunningham1,2
1Medical Biophysics, University of Toronto,
Toronto, ON, Canada, 2Imaging
Research, Sunnybrook Health Sciences Centre, Toronto,
ON, Canada, 3GE
Healthcare, Toronto, ON, Canada, 4Department
of Physiology, Anatomy and Genetics, University of
Oxford, Oxford, United Kingdom
We demonstrate the feasibility of imaging hyperpolarized
[2-13C] pyruvate and its major observable
Krebs cycle metabolite, [5-13C] glutamate, in
the heart, using a cardiac and respiratory-gated imaging
pulse sequence in vivo (TR 2.5s, 2 slices, 30mm in-plane
resolution). A spectral-spatial RF excitation was
designed to selectively excite either C2 pyruvate or C5
glutamate, while avoiding excitation of the remaining
resonances in the spectrum. The sequence is demonstrated
in vivo in pig hearts and provides a method to measure
spatially dependent changes in Krebs cycle metabolism in
vivo.
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15:00 |
3530. |
Localized in vivo
hyperpolarization transfer experiments
Mor Mishkovsky1,2, Tian Cheng1,
Rolf Gruetter1,3, and Arnaud Comment1,2
1Laboratory for Functional and Metabolic
Imaging, Ecole Polytechnique Fédérale de Lausanne,
Lausanne, Switzerland, 2Department
of Radiology, Université de Lausanne, Lausanne,
Switzerland, 3Department
of Radiology, Universités de Lausanne et de Genève,
Lausanne and Genève, Switzerland
In vivo localized and fully adiabatic homo- and
hetero-nuclear polarization transfer experiments were
designed and performed in the rat brain at 9.4T after
infusion of hyperpolarized 13C2 and
1-13C sodium acetate solutions. The new
scheme presented herein allows for highly enhanced in
vivo detection
of nuclear spins with short T1’s, including
protons, thus bringing new spectroscopic information on
hyperpolarized substrates and their metabolites. In
addition, in cases of narrow spectral dispersion,
indirect detection can improve the spectral resolution
such as in the case of 1-13C acetate of 15N
choline metabolism.
|
15:30 |
3531. |
Single-shot, Frequency and
Time Specific, 3D Imaging Method for Measuring
Hyperpolarized 13C Biomarkers In-Vivo at 14.1 Tesla ![](play.gif)
Subramaniam Sukumar1, Kayvan R Keshari1,
Robert Bok1, Vickie Zhang1, Andrew
Taylor1, Michael A Ohliger1,
Hikari Yoshihara1, John Kurhanewicz1,
and Daniel B Vigneron1
1Radiology and Biomedical Imaging, UCSF, San
Francisco, CA, United States
Hyperpolarized 13C biomarkers provide unique biochemical
information in-vivo but the short lived magnetization
requires special pulse sequences for acquiring the MRSI
data quickly and efficiently. High field systems pose
further challenges because artifacts related to wide
chemical shift dispersion, T2* and motion are increased.
We developed a novel, single shot, chemical shift
specific 3D imaging method which is particularly suited
for high field studies involving hyperpolarized 13C
biomarkers. We have used the technique for studying
various disease models in mice at 14.1T.
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Tuesday May 10th
|
13:30 - 15:30 |
Computer 50 |
13:30 |
3532. |
Free-breathing cardiac and
respiratory-gated imaging of hyperpolarized pyruvate and
bicarbonate in the heart ![](play.gif)
Angus Zoen Lau1,2, Albert P Chen3,
Marie A Schroeder2,4, Wilfred W Lam2,
Yiping Gu2, Jennifer Barry2, and
Charles H Cunningham1,2
1Medical Biophysics, University of Toronto,
Toronto, ON, Canada, 2Imaging
Research, Sunnybrook Health Sciences Centre, Toronto,
ON, Canada, 3GE
Healthcare, Toronto, ON, Canada, 4Department
of Physiology, Anatomy and Genetics, University of
Oxford, Oxford, United Kingdom
We incorporate respiratory gating into a rapid
multi-slice single-shot cardiac 13C
imaging pulse sequence. This provides time-resolved
imaging of hyperpolarized [1-13C]pyruvate,
[1-13C]lactate, and 13C
bicarbonate in vivo (TR 2.5s, 2 slices, 9 mm in-plane
resolution), allowing for capture of the first pass of
the tracer bolus and images of downstream metabolites at
later times after they have appeared. The sequence is
demonstrated in vivo in pig hearts and may provide
improved quantitative measurements of 13C
metabolism in vivo.
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14:00 |
3533. |
Improving estimation of
intracellular hyperpolarized 1-13C-pyruvate
kinetics by co-injection of gadolinium contrast agent ![](play.gif)
Matthew Smith1, Eric Peterson2,
Jeremy Gordon1, Kang Wang1, Ian
Rowland3, and Sean Fain1,3
1Medical Physics, University of Wisconsin,
Madison, WI, United States, 2Biomedical
Engineering, University of Wisconsin, Madison, WI,
United States, 3Radiology,
University of Wisconsin, Madison, WI, United States
Hyperpolarized 13C-labeled
pyruvate studies with MR have been used to observe the
dynamic 13C
label transfer to other metabolites. In this work, we
first investigate the limitations of kinetic modeling of
the in-vivo 13C
label transfer using a widely used two-site exchange
model and demonstrate a novel technique to provide
contrast to the intracellular compartment by injecting a
Gd-chelate following the injection of HP 13C-pyruvate
to provide T1-shortening to non-intracellular
compartments. We also provide a kinetic model that
distinguishes the intracellular space by utilizing this
contrast.
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14:30 |
3534. |
Hyperpolarized Water for
Interventional Angiography ![](play.gif)
Jan Henrik Ardenkjaer-Larsen1, Christoffer
Laustsen2, Benjamin Pullinger3,
Stephen Kadlecek3, Kiarash Emami3,
and Rahim Rizi3
1GE Healthcare, Broendby, Denmark, 2DRCMR,
Hvidovre, Denmark, 3University
of Pennsylvania, United States
We demonstrate a novel method of hyperpolarizing water
based on the dissolution-DNP method. The method has
several advantages: a) very high polarization (tens of
percent) and b) long relaxation times (by dilution in
D2O). A magnetization equivalent to more than 70 T is
demonstrated in phantoms. The applicability of the
method is demonstrated in the rat by several
angiographic acquisitions.
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15:00 |
3535. |
Interrogating
Tricarboxylic Acid Cycle: A Comparative Study by
Hyperpolarized Succinic Acid and its Diethylester
Pratip Bhattacharya1, Niki Zacharias1,
Henry Chan1, Napapon Sailasuta1,
Larry W Robertson1, Alan Epstein2,
and Brian D Ross1
1Enhanced MR Laboratory, Huntington Medical
Research Institutes, Pasadena, CA, United States, 2Pathology,
University of Southern California, Los Angeles, CA,
United States
The goal of this work is to interrogate the succinate
level in the cytosol by hyperpolarization of succinate,
a key metabolite of Tricarboxylic Acid Cycle (TCA) and
its diethyl ester derivate. Succinate Dehydrogenase
(SDH)-catalyzes the oxidation of succinate to fumarate
with the reduction of ubiquinone to ubiquinol and is an
oncogene defined in many cancers. Here we demonstrate
different metabolic profiles in vivo using two molecules
with slight variations but with very different uptake
rates. Hyperpolarized diethyl ester of succinic acid
(diethylsuccinate) is taken up rapidly in vivo in both
normal and tumor bearing mice, while hyperpolarized
succinic acid is apparently taken up only in some tumor
bearing animals. The results underscore the importance
of chemical modification in choosing molecular targets
to achieve desired metabolic imaging using
hyperpolarization.
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Wednesday May 11th
|
13:30 - 15:30 |
Computer 50 |
13:30 |
3536. |
Study of acetyl carnitine
kinetics in skeletal muscle in
vivo using
hyperpolarized 1-13C acetate ![](play.gif)
Jessica A M Bastiaansen1, Tian Cheng1,
Mor Mishkovsky1,2, Arnaud Comment1,2,
and Rolf Gruetter1,3
1Laboratory of Functional and Metabolic
Imaging, Ecole Polytechnique Fédérale de Lausanne,
Lausanne, Switzerland, 2Department
of Radiology, Université de Lausanne, Lausanne,
Switzerland, 3Department
of Radiology, Université de Lausanne et Genève, Lausanne
and Geneva, Switzerland
Carnitine plays a vital role in the regulation of muscle
fuel metabolism and buffers mitochondrial acetyl CoA via
rapid conversion into acetyl carnitine. Hyperpolarized 13C
MR offers the possibility to directly monitor acetyl
carnitine kinetics and provides significant new
information about its metabolism. Herein, we studied
acetyl carnitine kineticsin vivo following
injections of hyperpolarized 1-13C acetate.
Using a one site exchange metabolic model, we
investigated acetyl carnitine formation in skeletal
muscle in vivo and determined its kinetics to provide a
paradigm for future studies involving altered pathology.
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14:00 |
3537. |
Spectral-spatial EPI
sequence with frequency correction for dynamic 3D imaging of
pre-polarized 13C metabolites ![](play.gif)
Charles H. Cunningham1,2, Ralph E. Hurd3,
and Albert P. Chen4
1Imaging Research, Sunnybrook Health Sciences
Centre, Toronto, ON, Canada, 2Medical
Biophysics, University of Toronto, Toronto, ON, Canada, 3GE
Healthcare, Menlo Park, CA, United States, 4GE
Healthcare, Toronto, ON, Canada
Motivated by the need for 3D metabolic images at
multiple timepoints, a rapid spectral-spatial
echo-planar imaging (ss-epi) pulse sequence tailored for
clinical application was developed. The feasibility of
using registration of consecutive metabolic images as a
method for measuring and correcting the
frequency-induced spatial shifts that occur in
vivo was
investigated. In experiments with rats and
hyperpolarized [1-13C] pyruvate, excellent image quality
and apparent agreement with the underlying anatomy was
observed. The frequency correction method was shown to
have an accuracy of 3 Hz.
|
14:30 |
3538. |
Producing >60,000-fold
room-temperature 89Y
NMR signal enhancement ![](play.gif)
Lloyd Laporca Lumata1, Ashish Jindal1,
Matthew Merritt1, Craig Malloy1,
Allan Dean Sherry1,2, and Zoltan Kovacs1
1Advanced Imaging Research Center, University
of Texas Southwestern Medical Center, Dallas, Texas,
United States, 2Department
of Chemistry, University of Texas at Dallas, Richardson,
Texas, United States
We present optimization studies of hyperpolarized 89Y
NMR signal which shows a relatively long polarization
lifetime T1~500 s. Liquid-state 89Y
NMR signal enhancement as high as 65,000 times the
thermal signal, which corresponds to a polarization of
10 %, has been achieved at room temperature in a 9.4 T
magnet after dynamic nuclear polarization of Y-DOTA
samples at 3.35 T and 1.4 K. The 89Y
NMR enhancement is optimized by varying the glassing
matrices and paramagnetic agents as well as doping the
samples with a gadolinium relaxation agent. The high
room-temperature NMR signal enhancement places 89Y,
one of the most difficult nuclei to do NMR spectroscopy,
in the list of viable magnetic resonance imaging (MRI)
agents when hyperpolarized under optimized conditions.
|
15:00 |
3539. |
In vivo assessment
of metabolism in the hypertensive rat heart using
hyperpolarized [1-13C] and [2-13C]pyruvate ![](play.gif)
Michael Samuel Dodd1,2, Daniel Ball1,
Marie A Schroeder1, Helen J Atherton1,
Lydia Le Page1, George K Radda1,
Houman Ashrafian2, Hugh Watkins2,
Kieran Clarke1, and Damian J Tyler1
1Physiology, Anatomy and Genetics, Oxford
University, Oxford, United Kingdom, 2Cardiovascular
Medicine, Oxford University, Oxford, United Kingdom
Spontaneously hypertensive rats (SHRs) display
hypertension, insulin resistance and concentric
hypertrophy. There is hypothesised to be a switch to a
glycolytic phenotype in SHRs. Using hyperpolarized
magnetic resonance spectroscopy, via dynamic nuclear
polarization, the metabolism of [1-13C] and
[2-13C]pyruvate was observed. This showed a
63% increase in PDH flux in SHRs and an increase in
label incorporation into acetylcarnitine and glutmate
pools, which is proportional to the increase in PDH
flux. No classical switch to a glycolytic phenotype was
observed, as flux into lactate remained unchanged
between groups. However, an increased reliance on
glucose oxidation through PDH, was observed.
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Thursday May 12th
|
13:30 - 15:30 |
Computer 50 |
13:30 |
3540. |
In vivo localized 15N
MRS detection of hyperpolarized 15N
labeled choline in the rat brain ![](play.gif)
Cristina Cudalbu1, Arnaud Comment1,
Tian Cheng1, Mor Mishkovsky1, and
Rolf Gruetter1,2
1Laboratory for Functional and Metabolic
Imaging (LIFMET), Ecole Polytechnique Fédérale de
Lausanne (EPFL), Lausanne, Switzerland, 2Departments
of Radiology, Universities of Lausanne and Geneva,
Geneva, Switzerland
We acquired localized in vivo hyperpolarized 15N Cho
spectra using two different voxel sizes in order to
investigate the spatial origin of the 15N Cho signal in
the rat brain. In the small voxel where the major blood
vessels contribution should be negligible, the in vivo
15N Cho signal was visible for more than 1 min. To our
knowledge the in vivo localized detection of
hyperpolarized 15N has not been demonstrated to date.
|
14:00 |
3541. |
Evaluation of
Heterogeneous Metabolic Profile in an Orthotopic Human
Glioblastoma Xenograft Model Using 3D Compressed Sensing
Hyperpolarized 13C MRSI ![](play.gif)
Ilwoo Park1, Simon Hu1, Robert Bok1,
Peter Shin1, Tomoko Ozawa2, C.
David James2, Sabrina M Ronen1,
Daniel B Vigneron1,3, and Sarah J Nelson1,3
1Surbeck Laboratory of Advanced Imaging,
Department of Radiology and Biomedical Imaging,
University of California, San Francisco, San Francisco,
CA, United States,2Brain Tumor Research
Center, Department of Neurological Surgery, University
of California, San Francisco, San Francisco, CA, United
States, 3Department
of Bioengineering and Therapeutic Sciences, University
of California, San Francisco, San Francisco, CA, United
States
We modified a previous compressed sensing scheme and
acquired hyperpolarized 13C 3D MRSI data from an
orthotopic human xenograft tumor model in rat brain. The
3.72-fold acceleration factor allowed the reliable
acquisition of hyperpolarized 13C 3D MRSI data with 4
times better resolution in approximately the same scan
time compared to the fully sampled data. The new
sequence was applied to evaluate heterogeneous metabolic
profiles within the tumor tissue of rats with brain
cancer. The results from this study suggest that this
technique may be used to differentiate brain tissue with
different tumor histology.
|
14:30 |
3542. |
Exchange Dynamics of a
Cryptophane-based Xenon Molecular Sensor ![](play.gif)
Richard Matthew Ramirez1,2, Todd K Stevens1,2,
Monica A Smith3,4, David E Wemmer1,4,
and Alexander Pines1,2
1Department of Chemistry, University of
California, Berkeley, Berkeley, CA, United States, 2Materials
Science Division, Lawrence Berkeley National Laboratory,
Berkeley, CA, United States, 3Biophysics
Graduate Group, University of California, Berkeley,
United States, 4Physical
Biosciences Division, Lawrence Berkeley National
Laboratory, Berkeley, CA, United States
The exchange dynamics of a xenon molecular sensor based
on cryptophane-A were elucidated by modeling the signal
decay generated by (CEST) against the McConnell-Bloch
equations to determine xenon dissociation rates from
cryptophane-A
|
15:00 |
3543. |
Detection of Glutaminase
Activity In
Vivo in a MYC
Mouse Model of Liver Cancer Using Hyperpolarized [5-13C]Glutamine ![](play.gif)
Simon Hu1, Hikari Yoshihara1,
Robert Bok1, Asha Balakrishnan2,
Andrei Goga2, John Kurhanewicz1,
and Daniel B Vigneron1
1Dept. of Radiology and Biomedical Imaging,
University of California at San Francisco, San
Francisco, CA, United States, 2Dept.
of Medicine, Division of Hematology/Oncology, University
of California at San Francisco, San Francisco, CA,
United States
Development of hyperpolarized technology utilizing
dynamic nuclear polarization has enabled the measurement
of 13C
metabolism in
vivo at
very high SNR. In this work, hyperpolarized [5-13C]glutamine
was used to probe glutaminase activity in
vivo in a
MYC oncogene driven liver cancer mouse model and in
normal mice. Slab-localized spectra were obtained, and
the areas associated with glutamine and glutamate peaks
were quantified. A significant increase in glutamate to
glutamine ratio (P = 0.0021) was detected in liver tumor
versus normal tissue. MYC transcription has been linked
with increased glutamine catabolism, a phenomenon termed
glutamine addiction, which is consistent with the
increased glutaminase activity we observed.
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