Electronic Posters: Neuroimaging - ismrm

15:00 4421. Clinical Significance of Ischemic Hypointense Findings in Vessels and Tissue in
Gradient Echo T2*-Weighted Images at 3 Tesla Evaluated by Simple Visual Estimation in
Stroke Patients Treated with Intravenous Rt-PA
Masafumi Harada 1 , Hitoshi Kubo 1 , Naomi Morita 2 , Hiromu Nishitani 2 , Tsuyoshi
Matsuda 3
1 Department of Medical Imaging, Univeristy of Tokushima, Institute of Health Biosciences, Tokushima City,
Tokushima, Japan; 2 Department of Radiology, Univeristy of Tokushima, Institute of Health Biosciences,
Tokushima City, Tokushima, Japan; 3 GE Healthcare Japan, Hino, Tokyo, Japan
The purpose of this study was to determine the clinical significance of Ischemic vessels (IschV) and tissue (IschT) signs in gradient
echo T2*-weighted images (Gre T2*-WIs) and the correlation of clinical outcome with visual recognition of these signs. The current
study may indicate that IschT sign in Gre T2*-WI at 3 tesla would include more severe ischemia than IschV sign and is therefore a
candidate for determination of risk for deteriorated outcome with Gre T2*-WI at 3 tesla.
MRA & CSF Studies with Clinical Applications
Hall B Monday 14:00-16:00 Computer 83
14:00 4422. Resolving Arterial Contributions in Vessel Encoding Dynamic Angiography
Michael A. Chappell 1,2 , Tom W. Okell 1 , Peter Jezzard 1 , Mark W. Woolrich 1
1 FMRIB Centre, University of Oxford, Oxford, United Kingdom; 2 Institute for Biomedical Engineering,
University of Oxford, Oxford, United Kingdom
Using a Vessel Encoded Arterial Spin Labelling preparation it is possible to provide non-invasive vessel selective angiography.
However, the ability to separate the contributions from all the labelled arteries, e.g. all four carotids and vertebrals, can be limited by
the specification of the acquisition. Here a new analysis method for VE-ASL data, that can separate different vessel contributions with
even limited data, is modified and applied to angiographic images. Results for separation of carotids and vertebral are presented
indicating that this is a viable alternative to highly invasive intra-arterial contrast methods.
14:30 4423. Flow Velocity Measurement in the Carotid Bifurcation Using 4D Flow-Sensitive
MRI and Doppler Ultrasound
Andreas Harloff 1 , Timo Zech 1 , Felix Wegent 1 , Simon Bauer 1 , Martin Schumacher 1 ,
Michael Markl 1
1 University Hospital Freiburg, Freiburg, Baden-Württemberg, Germany
Flow-sensitive 4D MRI was used to assess absolute blood flow velocities within the carotid bifurcation in healthy volunteers and
patients with high-grade internal carotid artery (ICA) stenosis before and after carotid endarterectomy. MRI data were compared with
Doppler ultrasound as the reference method. Reliability and reproducibility of MRI based measurements were tested. Velocity
measurement was feasible at any desired site of the carotid bifurcation. Compared to Doppler ultrasound, however, MRI
underestimated systolic blood flow velocity by approximately 30%.
15:00 4424. Implementing VERSE for Time of Flight RF Pulses at 7Tesla: Methodological
Considerations
Sebastian Schmitter 1 , Soeren Johst 2 , Michael Bock 2 , Kamil Ugurbil 1 , Pierre-Francois van
de Moortele 1
1 University of Minnesota, Center for Magnetic Resonance Research, Minneapolis, MN, United States; 2 German
Cancer Research Center, Heidelberg, Germany
It has been shown that successful Time-of-flight (TOF) images can be obtained at 7T benefiting from higher SNR and longer tissue
T1. However, because of SAR constraints, magnetization transfer pulses that are used at 1.5T/3T cannot be used at 7T, saturation
pulses are often skipped and the flipangle is limited. These issues can be addressed using the VERSE principle to decrease SAR.
However, VERSE pulses are more sensitive to δB0. Here, we investigate in simulations and in vivo the impact of off-resonance
frequencies on RF excitation profile of ramp shaped RF pulses (TONE) when applying VERSE at 7T.
15:30 4425. Insight Into the Anatomy of Cerebrospinal Fluid Flow in the Human Ventricular
System Using MR
Velocity Mapping
Andreas Stadlbauer 1 , Wilma van der Riet 2 , Erich Salomonowitz 1
1 MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, St. Poelten, Austria; 2 European
MRI Consultancy (EMRIC), Strasbourg, France
To study the spatial and temporal dynamics of CSF flow in the ventricular system of 40 normal volunteers using time-resolved 3D
magnetic resonance velocity mapping. Classification of CSF flow based on calculation of 3D particle path lines over the cardiac cycle
revealed one uniform flow pattern for the lateral ventricles, three categories for the third and two categories for the fourth ventricle.
We found no significant aging effects on both the presence of a specific CSF flow pattern and on flow velocities. Our results provide
the first detailed demonstration of the anatomy of CSF flow within the human ventricular system.