| Myocardial Perfusion & Spectroscopy |
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Thursday 23 April 2009 |
| Room 316A |
16:00-18:00 |
Moderators: |
Ulrike A. Blume and Robert G. Weiss |
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16:00 |
699. |
Qualitative and Quantitative
Myocardial Perfusion with Arterial Spin Labeling |
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Ulrike Blume1,
Matthias Guenther2, Amedeo Chiribiri1,
Sven Plein1,3, Tobias Schaeffter1
1Division of Imaging Sciences, King's College
London, London, UK; 2University Clinic of
Neurology, Mannheim, Germany; 3Academic
Unit of Cardiovascular Medicine, University of
Leeds, Leeds, UK |
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Arterial spin labelling
(ASL) is an alternative to first pass imaging and
can be performed without the need for contrast
agent. Perfusion imaging using ASL can therefore be
repeated several times and requires no timing of a
bolus of contrast agent. In this study, the
combination of qualitative and quantitative
assessment of myocardial perfusion is presented in
only two breath holds. Therefore this technique can
be applied multiple times at different positions to
fully assess the whole myocardium. Furthermore, a
quantitative assessment can then be planned on these
images and the absolute quantification of myocardial
perfusion allows acquisition of high resolution
perfusion-maps in one single breath hold. |
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16:12 |
700. |
Improved Arterial Spin
Labeling After Myocardial Infarction in Mice Using
Respiratory and Cardiac Gated Look-Locker Imaging
with Fuzzy C-Means Clustering for T1 Estimation |
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Moriel H. Vandsburger1,
Robert L. Janiczek1, Brent A. French1,2,
Craig H. Meyer1, Christopher M. Kramer2,3,
Frederick H. Epstein1,2
1Biomedical Engineering, University of
Virginia, Charlottesville, VA, USA; 2Radiology,
University of Virginia, Charlottesville, VA, USA;
3Medicine, University of Virginia,
Charlottesville, VA, USA |
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Measurment of myocardial
perfusion in mouse models of acute myocardial
infarction (MI) by arterial spin labeling (ASL) has
never been demonstrated. We developed a
cardio-respiratory gated Look-Locker spiral ASL
sequence which uses a fuzzy C-means (FCM) clustering
algorithm to reconstruct ASL images and assign image
inversion times (TIs). This reduced motion artifacts
and improved quantification of perfusion. Mice were
scanned at baseline (n=7) and one day after MI
(n=6). Baseline perfusion of 3.5 ± 0.3 (ml/g•min)
rose after MI in the noninfarcted zone to 4.5 ± 0.4
(ml/g•min) and dropped in the infarcted zone to 1.9
± 0.3 (ml/g•min). |
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16:24 |
701. |
Reconstruction of
Free-Breathing Myocardial Perfusion MRI Using
Simultanous Modeling of Perfusion and Motion (SMPM)
and Arbitrary K-Space Sampling |
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Henrik Pedersen1,
Henrik B.W. Larsson1, Rasmus Larsen2
1Functional Imaging Unit, Glostrup Hospital,
Glostrup, Denmark; 2DTU Informatics,
Technical University of Denmark, Lyngby, Denmark |
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Respiratory motion of
the heart represents a major practical problem in
myocardial perfusion MRI, because it hampers
perfusion quantification and causes residual
aliasing artifacts in modern k-space undersampling
techniques. This work presents a computational
framework that allows simultaneous modeling of
perfusion and motion (SMPM) for arbitrary k-space
sampling strategies. We demonstrate the SMPM concept
for a representative free-breathing myocardial
perfusion data set using 1) fully sampled k-space
data, 2) undersampled Cartesian k-space data, and 3)
undersampled radial k-space data. Results show that
the SMPM approach fits the original data well, both
with fully sampled k-space data and 8-fold radial
undersampling. |
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16:36 |
702. |
Myocardial Perfusion MRI Using
SW-CG-HYPR in Canines with Improved Spatial
Coverage, Resolution and SNR |
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Lan Ge1,
Aya Kino1, Daniel Lee1, Rohan
Dharmakumar1, Mark Griswold2,
Charles Mistretta3, James Carr1,
Debiao Li1
1Northwestern University, Chicago, IL, USA;
2Western Reserve University, OH, USA;
3University of Wisconsin-Madison, WI, USA |
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The diagnostic value of
myocardial perfusion MRI is limited by the low
spatial coverage, resolution, SNR, and cardiac
motion related image artifacts. This work compared
SW-CG-HYPR method with conventional clinical
protocols for myocardial perfusion and demonstrated
the feasibility of SW-CG-HYPR method for detecting
the myocardial territory supplied by a stenotic
coronary artery using a controlled animal model.
Using this method, the acquisition time per slice
was reduced by a factor of 4, which should
substantially reduce cardiac motion artifacts; the
number of slices was doubled; the spatial resolution
was improved by a factor of 2 and the SNR by >50% as
compared to conventional methods. |
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16:48 |
703. |
First Pass Contrast Enhanced
MRI Shows Disparate Manifestations in
Exercise-Induced Perfusion Improvement in Non-Transmural
Infracted and Remote Myocardium |
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Mao-Yuan Marine Su1,
B-C Lee2, Y-W Wu2, H-Y Yu3,
W-C Chu4, W-Y I. Tseng5
1Institute of Biomedical Engineering, National
Yang-Ming University, Taipei, Taiwan; 2Internal
Medicine, National Taiwan University Hospital;
3Surgery, Natioanl Taiwan University Hospital;
4Institute of Biomedical Engineering,
Natioanl Yang-Ming University; 5Center
for Optoelectronic Biomedicine, National Taiwan
University College of Medicine, Taipei, Taiwan |
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Previous studies have
demonstrated that exercise training can improve
myocardial perfusion for patients with myocardial
infarction (MI).However, the effect of exercise
training on the non-transmural infarct myocardium
and residual viable myocardium still remains
unclear. Using MRI, our results suggest that the
effects of exercise training on the non-transmural
infarct and non-infarct remote zone might be
different. In the remote zone, improvement of MPR
after exercise training is mainly due to reduced
coronary vascular resistance. For the residual
viable myocardium in the non-transmural infarct
zone, the observed increased stress perfusion might
be attributed to exercise-induced angiogenesis. |
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17:00 |
704. |
Measurements of Myocardial
Perfusion and Metabolism with MR: Validation Study
with PET in a Canine Model |
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Kyle Stephan McCommis1,
Thomas A. Goldstein1, Dana R. Abendschein2,
Bernd Misselwitz3, Robert J. Gropler1,
Jie Zheng1
1Mallinckrodt Institute of Radiology,
Washington University School of Medicine, St. Louis,
MO, USA; 2Cardiovascular Division,
Washington University School of Medicine, St. Louis,
MO, USA; 3Bayer Schering Pharma AG,
Berlin, Germany |
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In this ongoing study,
MRI methods to quantify myocardial perfusion and
oxygenation were validated in a canine model at rest
and during pharmacologically induced hyperemia by
PET imaging. The MRI methods can quantify myocardial
blood flow (MBF), blood volume (MBV), oxygen
extraction (OEF), and oxygen consumption (MVO2). A
black-blood turbo spin-echo sequence was used to
measure the myocardial T2, and a 2-compartment model
was used to measure hyperemic myocardial OEF. MBF/MBV
were determined with a turboFLASH perfusion
sequence. MVO2 was determined with Fick’s law. The
MRI results in MBF, OEF, and MVO2 agreed well with
the “gold standard” PET measurements. |
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17:12 |
705. |
In Vivo Assessment of
Calcium Influx in Alpha-Dystrobrevin Knock-Out Mouse
by Manganese-Enhanced MRI |
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Wen Li1,2,
Jia Zhong1,2, Ya Chen1,2,
Laurie Castel3, Ming Lu1,2,
Wei Li1,2, David van Wagoner3,
Xin Yu1,2
1Department of Biomedical Engineering, Case
Western Reserve University, Cleveland, OH, USA;
2Case Center for Imaging Research, Case
Western Reserve University, Cleveland, OH, USA;
3Department of Molecular Cardiology, Cleveland
Clinic, Cleveland, OH, USA |
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This study aims to
explore the sensitivity of MEMRI in detecting
changes of calcium handling in an α-dystrobrevin
knockout mouse model, which showed higher calcium
influx through the L-type calcium channel from whole
cell patch clamp studies. Intraperitoneal injection
of 12.6 μmol MnCl2 led to a 37% signal enhancement
for both knockout and control groups. The increased
calcium influx in knockout mice was reflected by
significantly earlier and faster (19.4 vs 13.3
min-1) signal enhancement in MEMRI experiment. This
study suggests that in vivo MEMRI is
sensitive to subtle changes of calcium influx
associated with disruption in signaling gene. |
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17:24 |
706. |
New Methods for the
Quantification of Myocardial Oxygen Consumption with
17O MRI |
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Kyle Stephan McCommis1,
Xiang He1, Dana R. Abendschein2,
Pradeep M. Gupte3, Robert J. Gropler1,
Jie Zheng1
1Mallinckrodt Institute of Radiology,
Washington University School of Medicine, St. Louis,
MO, USA; 2Cardiovascular Division,
Washington University School of Medicine, St. Louis,
MO, USA; 3Rockland Technimed Ltd, Airmont,
NY, USA |
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A new MRI method is
presented to calculate the myocardial oxygen
consumption rate (MVO2) using 17O-enriched
blood. Initial in vivo study was performed in
normal dogs, as well as in one dog with a severe
coronary stenosis. A cardiac T1ρ
-weighted imaging sequence was developed to monitor
myocardial T1ρ signals with and without
the presence of metabolic H217O
water. Various doses of 17O-blood were
injected intravenously, followed by the injection of
16O-blood. MVO2 can then be
quantified using a simplified model. |
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17:36 |
707. |
High Energy Phosphate Cardiac
Energetics Are Abnormal in Primary Biliary Cirrhosis
Patients in the Absence of Functional or Anatomical
Abnormalities on Structural MRI |
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Kieren Grant
Hollingsworth1, David EJ Jones2,
Jessie Pairman2, Katherine Wilton2,
Roy Taylor1, Julia Lindsay Newton2,
Andrew Mark Blamire1
1Newcastle Magnetic Resonance Centre,
Newcastle University, Newcastle, Tyne and Wear, UK;
2Institute of Cellular Medicine,
Newcastle University, Newcastle, Tyne and Wear, UK |
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Primary Biliary
Cirrhosis is an autoimmune liver disease affecting
females from middle age. A follow-up study of 770
PBC patients studies indicated an increased risk of
cardiac-related death. Phosphorus MRS and anatomical
imaging for cardiac morphology were acquired to look
for cardiac metabolic stress and dysfunction. For 15
PBC patients, the PCr/ATP ratio was significantly
reduced compared to age and weight-matched control
subjects, but there was no difference in left
ventricle morphology, suggesting metabolic stress
only. There was no correlation between PCr/ATP
ratio, fatigue severity or age, suggesting that
cardiac metabolic stress is a systemic feature of
the disease. |
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17:48 |
708. |
31P TRIple TR
Saturation Transfer (TRIST) in the Human Heart at 3T |
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Michael Schär1,2,
AbdEl Monem El-Sharkawy1, Paul A.
Bottomley1,3, Robert G. Weiss1,3
1Russel H. Morgan Department of Radiology and
Radiological Science, The Johns Hopkins University
School of Medicine, Baltimore, MD, USA; 2Philips
Healthcare, Cleveland, OH, USA; 3Division
of Cardiology, Department of Medicine, The Johns
Hopkins University School of Medicine, Baltimore,
MD, USA |
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A new saturation
transfer method to measure the pseudo-first-order
rate constant kf of the creatine kinase
(CK) reaction employing just two fully-relaxed and
one short-TR acquisition is presented. This TRIST
method is validated by comparison with conventional
progressive saturation kf measures in the
human calf. It is then combined with 1D chemical
shift imaging to obtain the first 3T measures of CK
kinetics in the normal human skeletal muscle and
heart. |
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