Hall D Monday 14:00-16:00
14:00
2825.
Flow Sensitive MRI in a Realistic Model System of the Thoracic Aorta
with Aortic Coarctation
Computer 1
Ramona
Lorenz1, Aurélien F. Stalder1, Jelena Bock1,
Dominic Klausmann2, Christoph Benk1, Jürgen Hennig1,
Michael Markl1
1University
Hospital Freiburg, Freiburg, Germany; 2University Freiburg,
Freiburg, Germany
The
purpose of this study was to establish a realistic model system for the
evaluation of hemodynamics consequences of aortic coarctation with different
stenosis grades. Flow sensitive 4D MRI was performed within a realistic rapid
prototyping vascular model of the thoracic aorta with attached flexible
stenosis in the descending aorta which was integrated into a pulsatile flow
circuit. A novel approach for generating realistic pulsatile waveforms was
realized by a pneumatically driven VAD (ventricular assistant device) pump
system. The study presents an evaluation of the impact of stenosis grade on
local and global flow dynamics.
14:30
2826.
Flow Sensitive 4D MRI: Descending Aortic Retrograde Flow and
Embolization Risk in Acute Stroke Patients
Computer 1
Michael
Markl1, Christoph Strecker2, Patrick Dudler2,
Andrea Nußbaumer2, Jelena Bock1, Aurelien F. Stalder1,
Alex Frydrychowicz1, Anna L. Stroh3, Cornelius Weiller2,
Jürgen Hennig1, Andreas Harloff2
1Dept.
of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg,
Germany; 2Dept. of Neurology, University Hospital, Freiburg,
Germany; 3Dept. of Cardiology, University Hospital, Freiburg,
Germany
Flow-sensitive
4D MRI allows the detailed visualization of both physiological and pathological
3D aortic blood flow characteristics and was used to determine the role of
retrograde flow in the descending aorta (DAo) in patients with acute embolic
stroke. Our findings demonstrate a high incidence of retrograde flow in the
proximal DAo suggesting that complex DAo plaques should be considered as a
novel high-risk embolic source in patients with undetermined stroke etiology.
15:00
2827.
Analysis of 3D Flow Dynamics in a Ventricular Assist Device by Flow
Sensitive 4D MRI
Computer 1
Michael
Markl1, Ramona Lorenz1, Jelena Bock1,
Christoph Benk2, Dominic Klausmann2, Alex Frydrychowicz1,
Jürgen Hennig1, Friedhelm Beyersdorf2
1Dept.
of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg,
Germany; 2Dept. of Cardiovascular Surgery, University Hospital,
Freiburg, Germany
The
assessment of flow characteristics inside ventricular assist devices (VADs)
using MRI techniques may provide insight into the mechanisms underlying the
high rate of thrombo-embolic events after VAD implantation. These
investigations may form the basis to optimize the device’s design and its need
for anticoagulation. The purpose of this study was to integrate a clinical routine
VAD into a flow circuit with realistic geometric and pulsatile inflow
conditions. Flow sensitive Magnetic Resonance Imaging (MRI) at 3 Tesla
permitted the detailed analysis of local and global 3D flow dynamics in a
realistic environment.
15:30
2828.
Diameter-Dependence of Aortic Hemodynamics: Does Size Matter?
Computer 1
Alex
Frydrychowicz1, Alexander Berger1, Aurélien F. Stalder1,
Maximilian F. Russe1, Andreas Harloff1, Mathias Langer1,
Jürgen Hennig1, Michael Markl1
1University
Hospital Freiburg, Freiburg, Germany
It
was the aim of this study based on flow-sensitive 4D MRI to analyze the
diameter dependence of aortic hemodynamics with respect to characteristic blood
flow patterns such as time to maximum arterial flow, duration of backward flow,
number of vortices, and the presence of helical flow, which can be correlated
to wall shear stress (WSS) and oscillatory shear index (OSI). The results of
this study indicate the method¡¯s potential to identify characteristic,
diameter dependent, aortic flow patterns. In a cohort of 62 individuals which
were subgrouped by the diameter of the ascending aorta (SAD-group ¡Ü 3.5cm <
LAD-group) we showed that the size of the aorta influences the hemodynamic
properties.
14:00
2829.
Multi-Dimensional Velocity Field Reconstruction from Sparsely Sampled 3D
Phase Contrast MRI
Computer 2
Kartik
Sivaram Sundareswaran1, Dave Harold Frakes1, Mark Fogel2,
Oskar Skrinjar1, Ajit P. Yoganathan1
1Georgia
Institute of Technology, Atlanta, Georgia, USA; 2Children's Hospital
of Philadelphia, Philadelphia, Pennsylvania, USA
A
new technique for velocity field reconstruction is presented in this paper that
utilizes blood flow incompressibility as a property for estimating continuous
flow field representation in blood vessels using a stack of contiguous phase
contrast MRI. The methodology has been tested on 15 in vivo datasets of
patients with a single ventricle circulation, and the results indicate superior
qualitative and quantitative velocity reconstruction compared to other traditional
techniques for flow reconstruction from PC MRI. This opens up new avenues for
higher order analysis (vortex structures, energy loss) of PC MRI flow fields.
14:30
2830.
In Vivo MR Determination of Flow Fields in Patients with Intracranial
Aneurysms Using 7D PC-MRI
Computer 2
Gabriel
Acevedo-Bolton1, Alastair Martin1, Vitaliy Rayz1,
Loic Boussel1, David Saloner1,2
1UCSF,
San Francisco, California , USA; 2VAMC San Francisco, San Francisco,
California , USA
7D
PC-MRI was used to measure and map the blood flow within intracranial aneurysms
in vivo. These flow results were compared
with in vitro reproductions and with the predictions of computational
fluid dynamics(CFD) models. It was found to be essential to determine all three
components of the velocity to adequately visualize the complex flow structures
15:00
2831.
Patient-Specific Hemodynamics of the Descending Aorta: Combination of
CFD and 4D Flow-Sensitive MRI
Computer 2
Aurélien
F. Stalder1, Zhenyu Liu2, Michael Markl1,
Jürgen Hennig1, Jan Korvink2
1University
Hospital Freiburg, Freiburg, Germany; 2University of Freiburg,
Freiburg, Germany
Flow-sensitive
4D MRI allows in vivo 3D blood flow
visualization and flow parameter estimation but is limited by spatio-temporal
resolution and measurement errors. In contrast, Computational Fluid Dynamics
(CFD) can compute very accurate flow fields from modeled arteries but depends
on the validity of the hemodynamic model and boundary conditions. We show for
the first time an integration of 4D flow-sensitive MRI and CFD into a single
framework. A combination of those 2 complementary approaches offers reciprocal
validation possibilities and has the potential to refine flow measurements
which may result in more accurate quantification of complex in vivo hemodynamic phenomena.
15:30
2832.
4D Flow of the Whole Heart and Great Vessels at 3T Using Real Time Self
Respiratory Gating
Computer 2
Sergio
Andres Uribe1, Philipp Beerbaum1, Allan Rasmusson2,
Thomas Sangild Sørensen2, Reza Razavi1, Tobias Schaeffter1
1Kings
College London, London, UK; 2University of Aarhus, Aarhus, Denmark
We
present an extension of a self-respiratory technique to acquire 4D flow data.
Self-navigation is obtained from k-space center profiles and the breathing
signal is used in real time to gate the scan. The method allows us to acquire
an isotropic non-angulated volume, 4D flow encoded, of the whole heart and
great vessel in a single free-breathing scan. Results showed a strong
correspondence between flow patterns obtained using this technique and with 2D
flow. This approach represents an important advance for the characterization of
the flow hemodynamics in the whole heart and a step forward to simplify cardiac
MR examinations.
Hall D Monday 14:00-16:00
14:00
2833.
A New Methodology for Determining Aortic Pulse Wave Velocity Using 2D
PCMR Velocity Data
Computer 3
Samuel
Fielden1,2, Brandon Fornwalt2, Michael
Jerosch-Herold3, Robert Eisner1, Arthur Stillman1,
John Oshinski1,2
1Emory
University, Atlanta, USA; 2Georgia Institute of Technology/Emory
University, Atlanta, USA; 3Oregon Health & Science University,
Portland, USA
A
novel method for estimating aortic pulse wave velocity is presented. This method uses 2D PCMR data to construct
blood velocity magnitude images in order to determine multiple flow waveforms
in the ascending, transverse, and descending sections of aorta. The waveform at each location is compared to
the most proximal waveform via cross correlation to determine the time delay of
the wave at that location and thus the pulse wave velocity. This method is more reproducible than either
of two more established methods examined.
14:30
2834.
Measurement of Aortic Pulse Wave Velocity in Volunteers
Computer 3
Neva
Hiten Patel1, Mark Butlin2, Richard T. Black1,
Martin J. Graves,13, Stacey Hickson4, Carmel McEniery4,
Ian B. Wilkinson4, David J. Lomas3
1Addenbrooke's
Hospital NHS Trust, Cambridge, UK; 2Macquarie University, Sydney,
Australia; 3University of Cambridge, UK; 4University of
Cambridge, Cambridge, UK
Aortic
pulse wave velocity (PWV) can be used as an index of the increased risk of
cardiovascular disease which is associated with aortic wall stiffness. A number
of groups have looked at measuring PWV using MRI, however we are not aware of
any reported studies addressing the best method of obtaining the transit-time
used to calculate the PWV, and the reproducibility of PWV measurement. We have
performed repeated MRI PWV measurements in healthy volunteers and investigated
several different methods of transit-time calculations.
15:00
2835.
The Effect of Wall Compliance on Aortic Hemodynamics in the Mouse:
Implications for AAA Pathogenesis
Computer 3
Smbat
Amirbekian1, Robert C. Long1, Jin Suo2, W
Robert Taylor1,2, Don P. Giddens2, John N.
Oshinski1,2
1Emory
University, Atlanta, Georgia, USA; 2Georgia Tech, Atlanta, Georgia,
USA
MRA
and PC-MRI were used to provide geometric and flow boundary conditions for a
computational study of the hemodynamics of the mouse aorta. The study showed that incorporating vessel
compliance changes the flow patterns seen in the aorta and that a rigid vessel
creates areas of oscillatory wall shear stress.
15:30
2836.
Measurement of Common Carotid Artery Lumen Dynamics During Cardiac Cycle
Using TrueFISP Cine MR Imaging
Computer 3
Tracy
Yee Mau Chow1,2, Jerry S. Cheung1, Yin Wu1,
Ed X. Wu1
1The
University of Hong Kong, Pokfulam, Hong Kong
Vascular
MR imaging provides detailed anatomical information of blood vessels, yielding
lumen size and wall thickness measurements. However, many of the studies often
specify the morphology and composition of vessel walls without examining the
dynamic pulsatile properties of these vessels. In this study, the vascular
dynamics of the right and left common carotid arteries throughout the whole
cardiac cycle was investigated using TrueFISP cine cardiac imaging. Consistent
results and area waveform patterns were observed among the normal subjects.
This lumen dynamics can better describe physiological behaviour correlated with
other vascular parameters, therefore has potential clinical importance in
differentiating abnormalities. Furthermore, TrueFISP cine MRI produces high
contrast images, allowing high accuracy in area measurements and thus waveform
tracing.
Hall D Monday 14:00-16:00
14:00
2837.
Spiral T2 Quality Evaluation in Patients with Coronary Artery Disease
Computer 4
Warren
Foltz1, Kim Alexander Connelly1, Ram Vijayaraghavan1,
Venkat Ramanan, Gideon Paul1, Graham Wright1, Alexander
Dick1
1Sunnybrook
Health Sciences Centre, Toronto, Canada
T2
has proven to be a valuable contrast mechanism for myocardial characterization
because it is a quantitative biomarker of acute and sub-acute inflammatory
processes. Clinical integration of T2 relies on T2-weighted black-blood fast-spin echo (FSE) imaging because
cardiac-gated imaging is achievable in breath-hold scan times and with useful
spatial resolutions. However the
information is semi-qualitative and the echo-train readout compromises T2
contrast. A magnetization-prepared spiral imaging method, termed T2prep, should
improve reproducibility in clinical quantification of myocardial T2 relaxation
because variability associated with coil shading is removed. In the absence of gross relaxation
fluctuations, current clinical myocardial FSE scanning is useful only to
delineate cardiac margins. Quantitative T2prep mapping reduces variability
towards physiological noise levels, providing more reproducible measurements
with the potential for faster scan times at minor cost to spatial resolution
and ROImin.
14:30
2838.
Using T2*-Maps as a Quantitative Indicator for Myocarditis
Computer 4
Karl-Heinz
Herrmann1, Diane Renz1, Pascal Baltzer1, Ines
Krumbein1, Jürgen R. Reichenbach1
1Friedrich-Schiller-University,
Jena, Germany
Diagnosis
of myocarditis with standard sequences like late enhancement, T2 TSE or
T2-weighted TIRM is not always conclusive because any through plane motion of
the myocardium causes inhomogeneous signal due to the repeated slice selective
inversion and excitation pulses. A quantitative T2*-map may be helpful in
quantifying, delineating and detecting edema associated with myocarditis.
15:00
2839.
Retrospective Correction for Induced Magnetic Field Inhomogeneity in
Measurements of Large-Vessel Hemoglobin
Oxygen Saturation by MR Susceptometry
Computer 4
Michael
Langham1, Tom Floyd2, Jeremy Magland1, Felix
W. Wehrli1
1University
of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA; 2Univesity
of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
The
main source of error in MR susceptometry is the static field inhomogeneity that
is characterized by low spatial-frequency modulation on the phase image.
High-pass filtering has previously been used in conjunction with shimming. We
propose an alternative method which acquires data without scanner-implemented
default shimming, and fit, after appropriate weighting and masking, the static
field inhomogeneity to a second-order polynomial. Compared to shimming, the
retrospective correction technique improved agreement between hemoglobin
saturations measured in different segments of a vessel (femoral versus
popliteal artery and vein) from three standard errors to less than one.
Computer 4
Vincenzo
Positano1, Alessia Pepe1, Anna Ramazzotti1,
Daniele De Marchi1, Brunella Favilli1, Eliana Cracolici2,
Maria Gabriella Brizi3, Maria Filomena Santarelli1,
Massimo Lombardi1, Luigi Landini4
1Institute
of Clinical Physiology, Pisa, Italy; 2University of Palermo,
Palermo, Italy; 3A. Gemelli University Hospital, Roma, Italy; 4University
of Pisa, Pisa, Italy
In
this study we investigate the relationship between segmental R2* heterogeneity
assessed by multi-slice multi-echo MRI and iron overload progression in a large
thalassemia major patient population. Real data were compared with a surrogate
data sets obtained stating that the inhomogeneous segmental distribution of R2*
would be generated by susceptibility artefacts. Inhomogeneities in R2*
myocardial distribution in iron overloaded subjects cannot be explained by the
effect of susceptibility artefacts, that are additive in the R2* domain and
should vanish at high iron overload levels. A possible interpretation is that a
true heterogeneity in iron overload distribution in TM patients exists.
Hall D Monday 14:00-16:00
Computer 5
David
C. Zhu1, J Kevin DeMarco1, Anthony T. Vu2
1Michigan
State University, East Lansing, Michigan, USA; 2GE Healthcare,
Waukesha, Wisconsin, USA
An
optimized 3D inversion recovery prepared fast spoiled gradient recalled
sequence with multiple echoes (IR FSPGR ME) on a 3T scanner for carotid plaque
imaging is presented. It maintains the
ability of its single-echo counterpart in blood and fat signal suppression at
the carotid region as well as the benefits of high-resolution volumetric
visualization and hemorrhage detection. The IR FSPGR ME sequence can
potentially further characterizes hemorrhage types through the generated T8* maps. In addition,
combining images from the individual echoes provides a higher signal-to-noise
ratio and thus improve image visualization.
Computer 5
Makoto
Obara1,2, Masatoshi Honda3, Rie Nozaki2,
Marc Van Cauteren1, Kagayaki Kuroda2
1Philips
Medical Systems, Minato-ku, Japan; 2Tokai University, Hiratsuka-shi,
Japan; 3Tokai University Hospital, Isehara-shi, Japan
3D
turbo field echo (TFE) sequence prepared by motion sensitized driven equilibrium
(3D-MSDE-TFE) was optimized for T1W and T2W carotid artery wall imaging and
compared to the conventional 2D double inversion recovery (DIR) turbo spin echo
(TSE). T1 and T2 contrasts of 3D-MSDE-TFE were controlled by adjusting the MSDE
preparation time, shot interval and acquisition flip angle. MSDE optimization
was achieved by changing the number of refocusing pulses from 1 to 4 using MLEV
scheme. Achieved T1 and T2 contrasts of the optimized 3D-MSDE-TFE were similar
to those of conventional 2D-DIR while scan time was 2 times faster. Therefore,
this approach may be appropriate for vessel wall screening.
Computer 5
Haiyue
Ju1, Xian Xu1, Lin Ma1, Zulong Cai1,
Youquan Cai1, Xinjiang Wang1, Jianming Cai1
1Chinese
PLA General Hospital, Beijing, People's Republic of China
We
aim to evaluate the relationship between the shape and location of superficial
calcification and intraplaque hemorrhage in the atherosclerotic carotid plaque.
One hundred and eighty three slices with superficial calcification in 51
patients were enrolled in this study. All the patients underwent 3T MRI
examination with a contrast-enhanced multi-contrast weighted protocol. This
study showed that the nodular type of superficial calcification in the
atherosclerotic carotid plague has higher possibility of simultaneous
occurrence with intraplaque hemorrhage than that of patchy type, whereas, in
hemorrhage group, the percentage of either marginal or central type of
superficial calcification is not significantly different from that in
non-hemorrhage group.
15:30
2844.
Gadolinium Contrast Enhancement of Carotid Atherosclerotic Plaque is
Associated with Symptomatic Status
Computer 5
Jianming
Cai1, Niranjan Balu2, Dongxiang Xu2, Haiyue Ju1,
Xian Xu1, Xihai Zhao1, Chun Yuan2
1Chinese
PLA General Hospital, Beijing, People's Republic of China; 2University
of Washington, Seattle, USA
Symptomatic
carotid atherosclerosis is known to be associated with plaque neovasculature
and inflammation. An increase in vasa vasorum accompanies the increased
inflammation and plaque neovasculature of advanced atheorsclerosis. The
increased blood supply from the vasa vasorum plexus surrounding the carotid
artery may be reflected in contrast enhancement (CE) patterns of the outerwall.
The association between outerwall CE on black-blood contrast-enhanced MRI
(CE-MRI) and symptomatic status was investigated in 24 patients. Outerwall CE
was clearly visualized by CE-MRI. Symptomatic status was found to be associated
with a more homogenous outerwall CE compared to asymptomatic arteries.
14:00
2845.
DSCT and 3T MR for Characterization of Carotid Plaque in Patients
Computer 6
John
J. Sheehan1, Natasha Berg2, Timothy Carroll2,
Peter J. Weale3, Renate Jerecic3, James C. Carr2
1Northwestern
University, Chicago, Ireland; 2Northwestern University, Chicago,
Illinois, USA; 3Siemens Medical Solutions, Chicago, Illinois, USA
Atherosclerotic
disease is a significant cause of morbidity and mortality. Recent studies have suggested that plaque
composition is an important prognostic factor and may be more predictive of
adverse outcomes than overall degree of stenosis. Previous studies have attempted to
characterize carotid plaque components using various imaging modalities. In this small patient study, we looked at the
relative efficacy of two new technologies, 3 Tesla (3T) MR and Dual Source CT
(DSCT) to evaluate plaque components. We
hypothesized that these modalities could provide improved depiction of plaque
components, which may have important diagnostic and therapeutic implications.
14:30
2846.
Single-Shot DENSE MRI of the Carotid Arteries
Computer 6
Alexander
Peter Lin1,2, Eric Bennett2, Yuan Le2,
Scott Fraser1, Han Wen2
1California
Institute of Technology, Pasadena, California , USA; 2National
Institutes of Health, Bethesda, Maryland, USA
DENSE
strain mapping of the carotid artery wall systolic distension provides regional
stiffness measures. However, the scan lasts several minutes, and segmented
k-space acquisition suffers from artifacts due to head-neck motion and
turbulent in-plane blood flow. This problem is solved with a single-shot
imaging sequence and rigid body image registration in postprocessing.
15:00
2847.
MRI-Based
Biomechanical Imaging: Role of Hemodynamic Forces on the Early Plaque Remodeling
Computer 6
Jie
Zheng1, Dana Abendschein1, Ruth J. Okamoto2,
Deshan Yang1, Kyle McCommis1, Bernd Misselwitz3,
Robert J. Gropler1, Dalin Tang4
1Washington
University School of Medicine, Saint Louis, USA; 2Washinton
University, Saint Louis, USA; 3Bayler Schering Pharma AG, Berlin,
Germany; 4Worcester Polytechnic Institute, Worcester, Massachusetts,
USA
Local
hemodynamic forces play important roles in the regulation of early
atherosclerosis progression and vessel remodeling. A MRI-based biomechanical
imaging technique was developed and evaluated in vivo in a porcine
atherosclerotic plaque model. A plaque targeted contrast-enhanced MR images
provided plaque structure for the computational modeling in this technique.
Progression and regression of the early plaques were observed and flow shear
stress show consistent findings with other reports. Furthermore, structures stress
and strain also demonstrated strong correlations with plaque progression and
regression, indicating multi-factors of hemodynamic effect to the early
atherogenesis.
15:30
2848.
Characterization of Ex Vivo Carotid Plaque with 3T MRI: A Comparison
with Histology
Computer 6
Natasha
Berg1, John Joseph Sheehan1, Peter J. Weale2,
Mark Morasch1, Nicole Mascheri1, James C. Carr1,
Timothy Carroll1
1Northwestern
University, Chicago, Illinois, USA; 2Siemens Medical Solutions,
Chicago, Illinois, USA
Atherosclerotic
disease of the carotid artery is a significant cause of morbidity and
mortality. Previous imaging techniques
have focused on quantifying stenosis in the vessel, but recent research
suggests that composition of plaque may be a more important prognostic factor. Ex vivo studies of carotid plaques have
attempted to characterize plaque using 1.5 T MR and have shown that 2D PDW, T1W
and T2W sequences on MRI may have some utility in demonstrating areas of
fibrous matrix and necrotic core. Here, we perform an intial evaluation of 3T
MRI in the characterization of ex-vivo carotid plaque specimens.
14:00
2849.
High-Resolution Multi-Contrast MRI Characterization of Rabbit
Atherosclerosis Using Clinical Pulse Sequences
Computer 7
Andre
Jean-Louis Belisle1,2, John A. Ronald,12, Kem
A. Rogers1, Brian K. Rutt,12
1University
of Western Ontario, London, Canada; 2Robarts Research Institute,
London, Canada
We
used multi-contrast ex vivo 3T MRI of aortic specimens from defined regions of
a low-level long-term cholesterol-fed rabbit model of atherosclerosis. The
objective was to collect high-resolution images using clinically available
pulse sequences to resolve the structural components of plaques and to provide
histological verification. The most complex regions of plaque appear to be in
the descending aortic arch which was demonstrated by all sequences and is
especially evident when compared to T2w controls. Eventually this research
could be used for visualizing the vulnerable plaque and direct further in vivo
research by specifying imaging target regions in the aorta.
Computer 7
Daohai
Xie1,2, Bensheng Qiu1, Jiangyang Zhang3,
Xiaoming Yang1
1University
of Washington, Seattle, Washington, USA; 2Suzhou University School
of Medicine, Suzhou, People's Republic of China; 3Johns Hopkins
University School of Medicine, Baltimore, Maryland, USA
Atherosclerotic
cardiovascular disease remains the leading cause of death in the developed
countries. Continuous efforts are warranted to understand more about the
pathogenesis and management of atherosclerotic cardiovascular disease.
High-field micro-MR technology offers both high spatial resolution and
whole-body coverage. This study focused on evaluation of capability using in
vivo and ex vivo micro-MRI to detect mouse atherosclerotic plaques, which was
correlated with histopathology. The
results of the current study may encourage the continued efforts to develop high-field
MR imaging techniques to characterize atherosclerotic plaques in vivo,
so-called ¡°in-vivo plaque pathology,¡± which should become an essential
imaging tool for early diagnosis and efficient treatment of atherosclerotic
cardiovascular disease.
15:00
2851.
in vivo MRI and MRA Assessment of Patency in a Novel Model of Vascular
Remodelling Using Patent Aortic Grafts
Computer 7
King
Kenneth Cheung1,2, Andrew R. Thompson3, H
Hafez4, Andrew M. Taylor2, Roger J. Ordidge1,
Stephen E. Humphries3, Mark F. Lythgoe2
1University
College London (UCL), London, UK; 2UCL, London, UK; 3Royal
Free & University College London Medical School, London, UK; 4St
Richards Hospital, Chichester, UK
Fibulin-5
(fbln-5) is an extracellular matrix protein that is central to elastic fibre
maturation and vessel development. A novel model has been devised to
investigate the role of fbln-5 in vascular remodelling in a patent vessel. As
sustained graft patency is central to this model, we evaluated the accuracy of
MRI and MRA for determining graft patency in
vivo. MRI and MRA correctly identified all patent (n=8) and non-patent
(n=3) grafts. The non-invasive and robust nature of MRI and MRA offers an
excellent alternative to traditional assessment through repeated invasive
surgery, thus improving survival and reducing animal usage.
Computer 7
King
Kenneth Cheung*1,2, Manfred Junemann-Ramirez*2,
Pauliina Lehtolainen2, Alan Rudiger2, Mark Turmaine,
David Sanz2, Roger J. Ordidge1, John F. Martin2,
Mark F. Lythgoe2
1University
College London (UCL), London, UK; 2UCL, London, UK
The
vascular endothelium is crucial in regulating biological functions such as
haemostasis. However this layer is often impaired in cardiovascular diseases.
Understanding the evolution of vascular remodelling is therefore of great
importance and may provide insights for the development of novel interventions.
Here we present the use of in vivo
MRI and vascular ultrasound in combination with ex vivo electron microscopy for extensive characterisation of the
events involved in vascular remodelling following balloon angioplasty of the
rat carotid artery over a 28 day follow-up period.
14:00
2853.
New Insights Into Ruptured Plaques: Enhanced Detection of Neovasculature
and Fibrous Tissue by MRI
Computer 8
Alkystis
Phinikaridou1, Kevin J. Hallock1, Ye Qiao1,
James A. Hamilton1
1Boston
University, Boston, Massachusetts, USA
We
used the Constantinides New Zealand White rabbit model to study atherosclerosis
and controlled plaque rupture associated with thrombosis. We combined contrast
enhanced (Gd-DTPA) in vivo (3T) and magnetization transfer (MT) ex vivo (11.7T)
MRI coupled to histology to identify features associated with vulnerable
plaques. In vivo, Gd-DTPA uptake was associated with plaque regions rich in
neovasculature as well as fibrous tissue. Ex vivo MT identified the location of
fibrous cap rupture and fibrosis seen within organized thrombi. Further studies
about the kinetics of Gd-DTPA within plaques together with the in vivo
application of MT will provide insights about plaque vulnerability.
14:30
2854.
Enhancement of the Atherosclerotic Plaque and the Vessel Wall of the
Carotid Artery After Injection of a Blood-Pool Contrast Agent
[Not Available]
Computer 8
Sietske
Rozie1, Piotr A. Wielopolski1, Mohamed Ouhlous1,
Wiro Niessen, Theo van Walsum, Aad van der Lugt1
1Erasmus
Medical Center, Rotterdam, Netherlands
Purpose:
We hypothesized that a blood-pool agent enhances the outer wall of the carotid
artery and specific parts of the atherosclerotic carotid plaque
Methods:
We studied 26 atherosclerotic plaques of 15 consecutive patients with severe
carotid stenosis. On a 3.0T scanner a 3DT1-weighted scan was performed before
injection and 20 minutes after injection.
Results:
The mean enhancement on the 20 minute delay scan was 40.9% ± 32.5% in the
non-calcified part of the plaque and 60.0% ± 21.7% in the vessel wall of the
symptomatic carotid arteries.
Conclusions:
Images obtained before and after contrast injection with Vasovist® may improve
atherosclerotic plaque characterisation and quantification.
15:00
2855.
In Vivo and ex Vivo plaque
Characterisation in the Aortic Arch of ApoE -/- Mice with High-Resolution
Multi-Parametric Magnetic Resonance Imaging at 17.6 Tesla
Computer 8
Gert
Klug1, Volker Herold1, Marco Parczyk1,
Elisabeth Bauer1, Thomas Schulze-Till1, Eberhard Rommel1,
Peter Jakob1, Wolfgang Bauer1
1University
of Wuerzburg, Wuerzburg, Germany
High-Resolution
plaque imaging in atherosclerotic apoE knock-out (-/-) mice has been recently
shown to correlate closely with histology. However these results are limited to
the aortic-root. We intended to further enhance the ability of high-field
magnetic resonance (MR) to characterize plaque formation in murine models of
atherosclerosis at microscopic levels. Our results demonstrate that high
resolution multi-parametric plaque imaging at 17.6 Tesla is feasible with good
correlation to HE histology but further studies are necessary to distinguish
plaque components compared to a more comprehensive histology protocol.
15:30
2856.
Molecular Imaging of Atherosclerosis Using Paramagnetic Cy5.5-Labeled
PEG-Micelles
Computer 8
Sjoerd
Hak1, Geralda A.F. van Tilborg1, Esad Vucice2,
Gustav J. Strijkers1, Klaas Nicolay1, Zahi A. Fayad2,
Willem Jan Menno Mulder2
1Eindhoven
University of Technology, Eindhoven, Netherlands; 2Mount Sinai
School of Medicine, New York, New York, USA
In
this study a new contrast agent for molecular imaging of atherosclerosis was
used, paramagnetic Cy5.5-labeled PEG-micelles. The targeting ligand used was
the RGD-peptide. In vivo MRI and ex vivo fluorescence techniques demonstrated
active uptake of RGD-PEG-micelles into atherosclerotic plaque in apoE-knockout
mice. The near infrared Cy5.5 fluorophore proofed to be very valuable for ex
vivo fluorescence imaging as there is less autofluorescence and better
penetration at higher wavelengths. The non-specific uptake of bare PEG-micelles
in mouse plaques was very limited. This makes this contrast agent very
attractive for molecular imaging of atherosclerosis, also when directed to
other targets.
Hall D Tuesday 13:30-15:30
13:30
2857.
Real-Time Cardiovascular Imaging Using a Combination of HYPR,
McKinnon-Bates, and COM Gating Algorithms
Computer 1
Lauren
A. Keith1, Dana C. Peters, Julia V. Velikina1
1University
of Wisconsin - Madison, Madison, Wisconsin, USA
We
use a combination of the HYPR and McKinnon-Bates algorithms along with center
of mass self-gating in order to improve spatial resolution, signal-to-noise
ratio and reduce artifact levels in real-time cardiovascular imaging.
Computer 1
Yu
Ding1, Yiu-Cho Chung2, Subha V. Raman3,
Orlando P. Simonetti3
1The
Ohio State University, Columbus, Ohio, USA; 2Siemens Medical
Solutions, Inc., Columbus, Ohio, USA; 3The Ohio State University,
Columbus, Ohio, USA
We
describe the characteristics and performance of a new temporal filter based on
the optimal linear transform, the Karhunen-Loeve Transform. The filter is
designed to suppress noise in dynamic cardiac MR images without compromising
the sharpness of stationary or moving edges or other structures. We derive a
simple mathematical formula for the noise reduction effect of this filter, and
then verify it in real-time cardiac cine MRI with TSENSE acceleration factor 4
in normal volunteers. A SNR gain of 144%
was achieved after filtering without edge blurring or other artifacts.
14:30
2859.
Dyadic Wavelet-Based Image Noise Suppression and Enhancement in
High-Speed Cardiac MR Parallel Acquisition
Computer 1
Qi
Duan1, Jian Chen1, Andrew Francis Laine1,
Vinay M. Pai2
1Columbia
University, New York, New York, USA; 2SUNY Upstate Medical
University, Syracuse, New York, USA
An
automated integrated denoising/enhancing approach was applied to images
acquired by parallel acquisition techniques in cardiac imaging. In comparison
with previous denoising only framework, this new proposed method could future
increase the CNR of the denoised images. Quantitative evaluation on phantom and
clinical data confirmed the benefit of this new method in terms of improving
CNR on parallel MR images. Preliminary results suggested that this new
integrated denoising/enhancing framework could further push the limits on the
temporal resolution by improving the SNR and CNR simultaneously.
15:00
2860.
3D Right Ventricular Strain and Geometry in Pulmonary Hypertension and
Normals
Computer 1
Bharath
Ambale1, Steven Lloyd2, Thomas Stewart Denney Jr.1,
Louis Dell'Italia2, Raymond Benza2, Himanshu Gupta2
1Auburn
University, Auburn, Alabama, USA; 2University of Alabama at Birmingham,
Birmingham, Alabama, USA
Accurate
assessment of right ventricular (RV) function is clinically important –
particularly in pulmonary hypertension (PHTN).
Compared to the left ventricle (LV), however, analysis of RV function is
relatively difficult. Unlike the LV, the
RV does not have geometric symmetry, precluding use of simple geometric models
to calculate RV volumes and wall stress.
Also, in PHTN, higher systolic blood pressure in the RV can cause
excursion of the interventricular septum into the LV cavity. As a result, the LV cavity can also lose its
geometric symmetry. This abstract
presents methods for reconstructing three-dimensional biventricular geometry
and strain in both normal volunteers and PTN patients.
Computer 2
Khaled
Zakarya Abd-Elmoniem1, Matthias Stuber1, Amr A. Youssef1,
Tetsuo Sasano1, Theodore P. Abraham1, Xiaofeng Lui1,
Sandeep Mullur1, Evert-Jan P. A. Vonken1, M. Roselle
Abraham1, Jerry L. Prince1
1The
Johns Hopkins University, Baltimore, Maryland, USA
We
present afast algorithm for direct and complete characterization of 3-D
time-course of principle strain orientations using data acquired with zHARP
imaging protocol from SA slices without the need for LA data. Using this
scheme, two or more SA slices are acquired and processed using zHARP and the
3-D strain tensor and principal strain angles are calculated. Results from infarct swine model shows that
strain orientations time-course can provide more information about heart
dynamics, especially when combined with efficient 3-D motion imaging.
Computer 2
Wei
Li1, Jia Zhong2, Xin Yu2
1Case
Western Reserve University, Cleveland , Ohio, USA; 2Case Western
Reserve University, Cleveland, Ohio, USA
Current
MRI tagging analysis often employs the first tagging image as the reference
frame. However, for a mouse heart, the first tagging image is frequently
acquired at early systole with significant tag line deformation due to fast
heart rate. In this study, a HARP-based method was develop to generate an
undeformed tagging grids. Myocardial deformation at early systole was analyzed
using this method.
14:30
2863.
Noise Measurement in Real-Time Cardiac Cine MRI Using Eigenvalues of
Karhunen-Loeve Transform
Computer 2
Yu
Ding1, Yiu-Cho Chung2, Subha V. Raman3, Orlando
P. Simonetti3
1The
Ohio State University, Columbus, Ohio, USA; 2Siemens Medical
Solutions, Inc., Columbus, Ohio, USA; 3The Ohio State University,
Columbus, Ohio, USA
Noise
measurement is difficult in real-time cine MRI using parallel acquisition
techniques because of cardiac and respiratory motion and the spatially variant
nature of both signal and noise. In this
work, we investigate using eigenvalues derived from the Karhunen-Loeve
Transform to assess mean noise standard deviation in dynamic MR cardiac images.
This method may have general application in the evaluation of dynamic imaging
methods, and other situations other methods of noise measurement are difficult
to apply.
15:00
2864.
DENSE-MR-Elastography for Cardiac Application
Computer 2
Benjamin
Robert1, Ralph Sinkus1, Jean-Luc Gennisson1,
Mathias Fink1
1Laboratoire
Ondes et Acoustique, Paris, France
Imaging
of mechanical shear waves via MR-Elastography (MRE) allows the assessment of
inherent viscoelastic tissue parameters. Cardiac MRE poses several technical
challenges: small relaxation times, time dependant viscoelastic properties
during the heart beat, respiratory motion. To overcome the short relaxation
time and the externally induced mechanical wave problems, a MRE sequence has
been adapted from a DENSE sequence.
Hall D Tuesday 13:30-15:30
Computer 3
Darren
Lum1, Reed Busse2, Christopher Francois1, Anja
Brau3, Philip Beatty3, Joshua Huff1, Jean
Brittain2, Scott Reeder1
1University
of Wisconsin - Madison, Madison, Wisconsin, USA; 2GE Healthcare,
Madison, Wisconsin, USA; 3GE Healthcare, Menlo Park, California ,
USA
We
utilize a 2D parallel imaging method (Autocalibrating Reconstruction for
Cartesian sampling - ARC) with 3D contrast enhanced MRA for complete abdominal
coverage within a breath hold. An
intra-individual comparison study between both parallel imaging accelerated and
non-accelerated exams was performed in 6 healthy volunteers. In addition 8 consecutive patients were
evaluated with 2D-ARC MRA. We find that
the subjective image quality of exams with 2D-ARC to be essentially equivalent
to those acquired without parallel imaging.
However, the 2D-ARC sequence provided a 3.5 fold increase in imaging
volume and a 30% reduction in voxel size in the same acquisition time.
Computer 3
Harald
Kramer1, Konstantin Nikolaou1, Henrik J. Michaely2,
Christian Glaser1, Maximilian F. Reiser1
1University
Hospitals Munich - Grosshadern Campus, Munich, Germany; 2University
Hospital Mannheim, Mannheim, Germany
Atherosclerosis
is a systemic vessel disease. MRI offers the possibility of whole body MRA with
excellent image quality and without ionizing radiation. First attempts to WB
MRA suffered from MR system Hardware restrictions, recent developments in MR
Hard- and Software like parallel imaging, dedicated coil systems and higher
field strength helped to increase image quality of WB MRA exams significantly.
Computer 3
Xiaohai
Ma1,2, Zhaoqi Zhang1, Yi He1,
Zhanming Fan1
1Beijing
Anzhen Hospital, Beijing, People's Republic of China; 2Michigan
State University, East Lansing, USA
Compared
to conventional CE-MRA, EZ-STEP is a timesaving method for thoracic aorta
imaging in 3T MR scanner, and also provides comparable image quality.
15:00
2868.
Calculating Peripheral MRA Bolus Timing Using Cine-Phase Contrast Flow
Measurements
Computer 3
Grace
Choi1, Ryan Brown1, Minh Chao1, Yi Wang1,
Martin R. Prince1
1Cornell
University - Weill Cornell Medical College, New York, USA
Total
Gadolinium dose can be reduced on whole body and peripheral MRA by using 2D
cine phase contrast MRA to calculate bolus velocity at 7 locations along the
arterial tree. Accuracy of this approach
was confirmed by comparison to bolus transit measurements from 1.8s temporal
resolution time-resolved MRA. Example
cases show diagnostic peripheral MRA with single dose gadolinium based contrast
agent. These data also show a 2-fold reduction in bolus transit time with
venous compression applied to thighs.
Hall D Tuesday 13:30-15:30
Computer 4
Florian
M. Vogt1, Stefan Maderwald1, Knut Kroeger1,
Gerhard Laub2, Randall Kroeker3, Joerg Barkhausen1,
Harald H. Quick1
1University
Hospital, Essen, Germany; 2University of California Los Angeles, Los
Angeles, California , USA; 3Siemens Medical Solutions, USA
Purpose was to develop a triple injection scan protocol for dynamic