| MRA & Flow of Neurovascular Disease |
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Monday 20 April 2009 |
| Room 311 |
14:00-16:00 |
Moderators: |
John Detre and J. Paul Finn |
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14:00 |
90. |
SWI-Based Intracranial MR Venography Using
Image-Domain High-Pass Filtering with Second-Order
Phase Difference |
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Yiping P. Du1,
Zhaoyang Jin2,3
1Psychiatry, Radiology, University of Colorado
Denver, Aurora, CO, USA; 2Institute of
Information and Control, Hangzhou Dianzi University,
Hangzhou, Zhejiang, China; 3Biomedical
Engineering, Zhejiang University, Hangzhou, Zhejiang,
China |
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An image-domain
high-pass filtering with second-order phase
difference is proposed to enhance the visibility of
venous vasculature and suppress the off-resonance
artifact in regions with severe field inhomogeneity
in susceptibility weighted imaging (SWI). Using this
filtering technique, 3D venography with positive
venous contrast is generated. A Fermi weighting
function is used to suppress the noise in air. The
proposed filtering approach circumvents the signal
loss commonly observed in the minimum-intensity
projection of 3D SWI data processed with a
conventional procedure. |
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14:12 |
91. |
3D Fast Inversion Recovery Magnetic Resonance
Angiography (FIR-MRA) |
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Ek Tsoon Tan1,
John III Huston1, Stephen J. Riederer1
1Radiology, Mayo Clinic, Rochester, MN, USA |
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A non-contrast-enhanced
MRA technique for imaging the intracranial arteries
is described. The complex difference between
selective and non-selective cycles of
inversion-prepared gradient echo subtracts out
static tissue, leaving only the vascular signal from
proximal blood flow during the inversion interval.
Each cycle also produces T1-weighted tissue
contrast, which may be fused with the angiogram-only
image for anatomical reference. A two-slab FIR-MRA
acquisition is compared against a three-slab
standard 3D time-of-flight sequence. FIR-MRA has
significantly improved vessel conspicuity,
background and artifact suppression but has a longer
scan time (11 min vs. 6.5 min). |
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14:24 |
92. |
High Resolution, Non-Contrast
Imaging of Both Cerebral Veins and Arteries by Use
of Gradient Echo T2 Star Weighted Angiography (SWAN) |
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Jennifer Linn1,
Jürgen Lutz1, Michael Burke2,
Tim Wesemann1, Hartmut Brückmann1
1Dept.
of Neuroradiology, University Hospital Munich,
Munich, Germany; 2GE Healthcare, Solingen,
Germany |
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Problem: To assess the
potential of T2 Star Weighted Angiography (SWAN) for
the depiction of cerebral veins and arteries.
Methods: A SWAN
sequence, and an arterial (MRA) and a venous (MRV)
TOF-MRA were performed on 12 volunteers using a 3T
MRI. MinIP and MIP images were analysed by two
readers regarding the depiction of cerebral veins
and arteries, respectively.
Results: The SWAN
sequence was superior compared to tMRV with regard
to the veins, and comparable to MRA with respect to
the arteries.
Conclusions: SWAN allows
for high-resolution, non-contrast visualization of
both cerebral veins and arteries without application
of contrast agent. |
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14:36 |
93. |
Non Contrast MRA of the
Extracranial Carotid Arteries Utilizing a 3D
ECG-Triggered Balanced Steady State Free Precession
Technique with Spatial Saturation |
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Calvin Lo1,
Bidyut K. Pramanik1, Daniel Kim1,
Xiaoming Bi2, Peter Weale2,
Anna Nazarenko1, Thomas P. Mulholland1,
Edmond A. Knopp1, Vivian S. Lee1,
Ruth P. Lim1
1Radiology,
NYU Langone Medical Center, New York, USA; 2Siemens
Medical Solutions USA, Inc., Chicago, IL, USA |
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An ECG-gated 3D balanced
steady state free precession (b-SSFP) MRA sequence,
utilizing an inversion pulse to null out background
tissue and a spatial saturation pulse to null out
slowly flowing venous blood, has been described to
visualize "fresh" arterial blood flowing into the
image. We assessed the feasibility, diagnostic
quality and accuracy of 3D b-SSFP MRA, compared with
conventional TOF MRA for evaluation of the
extracranial carotid arteries with reference to CE
MRA. We found significantly superior SNR, CNR, image
quality and diagnostic confidence for b-SSFP MRA
compared with TOF MRA, and high concordance for
stenosis with the reference standard. |
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14:48 |
94. |
High Resolution 3D MR Angiography Using Arterial
Spin Labeling |
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Yi
Wang1, Seong-Eun Kim2, Dennis
L. Parker1
1Utah Center for Advanced Imaging Research ,
University of Utah, Salt Lake City, UT, USA; 2Utah
Center for Advanced Imaging Research, University of
Utah, Salt Lake City, UT, USA |
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In this work, we used
arterial spin labeling to acquire 3D high resolution
angiography with increased signal to noise ratio. A
3D turbo-FLASH sequence was modified by
incorporating the in-plane slice-selective double
inversion magnetization preparation. Arterial blood
inflow time was determined experimentally and high
resolution 3D MR angiography was obtained at three
inversion times. |
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15:00 |
95. |
4D
Contrast Enhanced MRA with Flow Measurements (HYPR
FLOW) in Arteriovenous Malformations |
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Yijing Wu1,
Kevin M. Johnson1, Elizabeth J. Nett1,
Patrick Turski2, Charles A. Mistretta3
1Medical
Physics, University of Wisconsin, Madison, MADISON,
WI, USA; 2Radiology, University of
Wisconsin, Madison, MADISON, WI, USA; 3Medical
Physics and Radiology, University of Wisconsin,
Madison, MADISON, WI, USA |
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Phase Contrast (PC) HYPR
FLOW, which employs post contrast PC VIPR images as
the composite and reconstructs the first pass time
resolved contrast enhanced VIPR acquisition using
HYPR LR technique, is able to achieve 4D Contrast
Enhanced (CE) MRA with both high temporal resolution
and isotropic spatial resolution and quantitative
flow dynamics from the PC images. PC HYPR FLOW was
performed on normal subjects and patients with brain
AVMs. 4D CE MRA images with sub-second temporal
resolution and sub-millimeter isotropic spatial
resolution were generated as well as the flow
dynamic maps including the wall shear stress and
pressure. Quantitative measurements of velocity, WSS
and pressure gradients were conducted and compared
between control and patient groups. |
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15:12 |
96. |
4D-MRA in Combination with Selective Arterial Spin
Labelling for Functional Characterization of
Arteriovenous Malformations at 3 T |
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Guido Matthias Kukuk1,
Dariusch Reza Hadizadeh1, Jürgen Gieseke1,2,
Julia Bergener1, Gabriele Beck2,
Lisbeth Geerts2, Petra Mürtz1,
Azize Boström3, Horst Urbach1,
Johannes Schramm3, Hans Heinz Schild1,
Winfried Albert Willinek1
1Department of Radiology, University of Bonn,
Bonn, NRW, Germany; 2Philips Healthcare,
Best, Netherlands; 3Department of
Neurosurgery, University of Bonn, Bonn, NRW, Germany |
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4D-MRA is a promising
diagnostic tool for characterization of cerebral
arteriovenous malformations (cAVMs), however it
lacks the selectivity that is inherent to DSA.
Therefore we combined selective arterial spin
labelling (sASL) with 4D-MRA for anatomic and
functional characterization of cAVMs at 3.0 Tesla.
4D-MRA enabled the correct Spetzler-Martin
classification in 10/10 symptomatic patients. In
addition the sensitivity of identification of
arterial feeders and anatomic variants could be
markedly improved due to the combination with sASL.
Our data suggest, that 4D-MRA in combination with
sASL can provide functional information that so far
has been gained only with selective DSA. |
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15:24 |
97. |
The Influence of K-T BLAST on Intracranial
Aneurismal PC Velocity Mapping Data |
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Pim van Ooij1, Joppe J. Schneiders1,
Marieke E.S. Sprengers1, Ed van Bavel2,
Charles B.L.M. Majoie1, Aart J. Nederveen1
1Radiology, AMC, Amsterdam, Noord - Holland,
Netherlands; 2Biomedical Engineering &
Physics, AMC, Amsterdam, Noord - Holland,
Netherlands |
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k-t BLAST is a
measurement acceleration technique by undersampling
k-t space. This indicates that some data will be
lost during acquisition. It has been shown that
phase contrast angiography measurements in the aorta
can be accelerated without significant loss of data.
In this study it is tested if k-t BLAST can also be
used in PCA measurements of intracranial aneurysms
without significant loss of accuracy. It is shown
that if an aneurysm is large, results are more
accurate than in a small aneurysm. A possible
explanation is that small aneurysms contain a
relatively large amount of pixels where velocity is
low and thus where difference between full
measurement and k-t BLAST velocities is large. If
aneurysms are large enough (>5 mm), k-t BLAST can be
used without much loss of accuracy. |
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15:36 |
98. |
Cerebral Collateral Imaging in Patients with Carotid
Stenosis Using MR Perfusion Territory Arterial Spin
Labeling, Compared with DSA |
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Bing Wu1,
Xiaoying Wang1, Jia Guo2, Eric
C. Wong3, Jue Zhang2, Xuexiang
Jiang1
1Radiology
of Dept., Peking Uni. 1st hospital, Beijing, China;
2Interdisciplinary academy, Peking
University; 3Center for Functional
Magnetic Resonance Imaging and Departments of
Radiology and Psychiatry, University of California,
San Diego |
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This study was to
investigate the presence of collaterals in patients
with carotid stenosis and the change of perfusion
territory after internal carotid artery stent
therapy using the MR perfusion territory imaging. |
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15:48 |
99. |
TOF MR Angiography at 3.0 Tesla During Acetazolamide
Provocation Demonstrates Decreased Vasomotor
Reactivity Ipsilateral to a Carotid Artery Stenosis |
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Reinoud Pieter Harmen Bokkers1,
Frank J. Wessels2, H B. van der Worp3,
Jaco Zwanenburg4, Jeroen Hendrikse1
1Department of Radiology, UMC Utrecht,
Utrecht, Netherlands; 2Faculty of Medical
Sciences, University of Groningen, Groningen,
Netherlands; 3Department of Neurology,
UMC Utrecht, Utrecht, Netherlands; 4Image
Sciences Institute, UMC Utrecht, Utrecht,
Netherlands |
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The vasomotor reactivity
of the proximal and distal cerebral vasculature was
investigated in healthy subjects and patients with a
symptomatic stenosis of the ICA. High-resolution MRA
was performed at 3T before and 20 minutes after an
intravenous administration of acetazolamide. In
healthy subjects, vessel diameter increased
significantly in 10 of 11 measured arteries.
Arteries in hemispheres ipsilateral to the
symptomatic ICA showed no significant increase in
diameter, whereas in hemispheres contralateral to
the stenosis diameters increased significantly in
the proximal vasculature. Findings show that
high-field MRA combined with a vasodilatory
challenge may contribute to a better understanding
of vasomotor reactivity. |
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