TRADITIONAL POSTER - ismrm

Poster Sessions
2249. Blood Contrast Agent Concentration Measured by Dynamic MRI in Intra- And Extracranial Mouse
Vessels at 9.4 Tesla Using a Novel Cryogenic Probe
Melanie Heilmann 1 , Hanne Boll 2 , Sebastian J. Schambach 2 , Christoph Groden 2 , Marc A. Brockmann 2 ,
Lothar R. Schad 1
1 Computer-Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany; 2 Neuroradiology, University Medicine
Mannheim, Germany
Quantitative dynamic MRI requires knowledge of contrast agent (CA) concentration in blood. Due to the small size of murine vessels, so far an arterial input
function (AIF) has only been measured in mouse hearts. Using a novel cryogenic probe at 9.4 T, we measured CA kinetics in intra- and extracranial vessels.
Although high inter-individual variations were observed, in average, kinetics of the superficial temporal vein provided good estimates for blood CA
concentration. Smaller vessels suffered from partial volume effects but were less prone to inter-individual variations. Whether mouse perfusion studies
benefit from vessel-based AIFs, remains to be studied in future.
2250. Cerebral Blood Flow Change in One Hear Beat by CO2 Concentration Using Retrospective PC MRI
Measurements
Yi-Jui Liu 1,2 , Chun-Jung Juan 3 , Teng-Yi Huang 4 , Hsiao-Wen Chung 5 , Cheng-Yu Chen 3
1 Department of Automatic Control, Feng Chia University, Taichung, Taiwan; 2 Master's Program in Biomedical Informatics and
Biomedical Engineering, Feng Chia University, Taichung, Taiwan; 3 Department of Radiology, Tri-Service General Hospital and
National Defense Medical Center, Taipei, Taiwan; 4 Department of Electrical Engineering, National Taiwan University of Science and
Technology, Taipei, Taiwan; 5 Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
The purpose of this study was to evaluate the cerebral blood change in one cardiac cycle in different concentration of carbon dioxide inhalation. Using
retrospectively gated 2D phase contrast MRI is suitable method for measuring the velocity of cerebral arteries and veins during one hear beat. It is
noninvasive modality to quantify the blood flow and blood volume in one heart cycle with high spatial and temporal resolution. By this MR method, we
proceeded the experiment that observe the blood flow change during the CO2 concentration change.
2251. Quantification of Carotid Artery Blood Flow Before and After the Acetazolamide Challenge
Josephine Mary Reeve 1 , Dinesh Selvarajah 2 , Nyssa Craig 1 , Paul David Griffiths 1 , Solomon Tesfaye 2 , Iain
D. Wilkinson 1
1 Academic Radiology, University of Sheffield, Sheffield, S Yorkshire, United Kingdom; 2 Diabetes, Royal Hallamshire Hospital,
Sheffield, S Yorkshire, United Kingdom
Cerebrovascular reserve or the ability to vasodilate under stress may be a crucial physiological mechanism, providing increased arterial flux when necessary.
This study quantified flow within the internal carotid artery (ICA) in 14 normal young adults before and after administration of a carbonic anhydrase
inhibitor (acetazolamide). Quantitative flow assessment was based on a single-slice, multi-phase, fast-field echo sequence. Data was extracted via ROI
analysis. Significant increases in velocity, flux, apparent vessel diameter but not heart rate were observed following acetazolamide. This assessment provides
an objective in-vivo marker of the functional reserve of the macrovascular supply system.
2252. Towards True Arterial Intracranial TOF-MRA at 7T: Protocol Optimization Using VERSE Pulses
Soeren Johst 1 , Sebastian Schmitter 2 , Armin Nagel 1 , Wolfhard Semmler 1 , Michael Bock 1
1 Medical Physics in Radiology, German Cancer Research Center (dkfz), Heidelberg, Germany; 2 Center for Magnetic Resonance
Research, University of Minnesota, Minneapolis, MN, United States
TOF MRA highly profits from high fields, however, SAR restrictions limit the use of high-resolution protocols. In particular, venous suppression with
saturation pulses is difficult within clinically acceptable measurement times (TA ¡Ü 10min). Using the VERSE algorithm on the excitation pulses as well as
on the energy-intensive saturation pulses permits an effective SAR reduction that can be used to shorten the acquisition time. With a modified TOF MRA
pulse sequence high resolution intracranial MRA data sets with excellent venous suppression could be acquired in 10 min at 7 Tesla.
2253. Fast Inversion Recovery Magnetic Resonance Angiography (FIR-MRA) of the Intracranial Arteries
Ek Tsoon Tan 1 , John Huston III 1 , Norbert G. Campeau 1 , Stephen J. Riederer 1
1 Radiology, Mayo Clinic, Rochester, MN, United States
Spin-labeling-based FIR-MRA can provide high resolution 3D intracranial MRA. A detailed comparison of FIR-MRA (7.7 min) to standard 3D time-offlight
(TOF) MRA (6.5 min) was performed at 3 Tesla. Superior or equal vessel conspicuity, continuity, and venous suppression were demonstrated in eight
normal subjects with FIR-MRA. Three clinical studies were performed. In two patients with coiled aneurysms, FIR-MRA provided superior depiction of
aneurysm remnants to TOF. In one arteriovenous malformation (AVM) patient, FIR-MRA provided a clearer depiction of the AVM nidus than TOF and
contrast-enhanced MRA, and could differentiate between the arterial and venous components of the AVM.
2254. Assessment of the Supra-Aortic Vessels Using Time-Resolved Double-Bolus 3D TWIST-MRA
Andreas Korn 1 , Till K. Hauser 1 , Sören Danz 1 , Benjamin Bender 1 , Michael Fenchel 1 , Thomas Nägele 1 ,
Ulrike Ernemann 1 , Uwe Klose 1
1 Department of Neuroradiology, University Hospital Tübingen, Tübingen, Germany
MRA of the supra-aortic vessels is usually performed in CARE bolus technique, which necessitates high operator experience and interaction with the control
panel. TWIST requires less operator experience and interaction. Goal of the present work was to implement an automated and therefore robust protocol for
the TWIST angiography of the supra-aortic vessels with high spatial resolution and increased likelihood of optimal arterial contrast by double bolus
injection. The new double bolus injection protocol allowed for good separation of arterial vessels at least after one of the two bolus applications.