TRADITIONAL POSTER - ismrm

Poster Sessions
2575. Proton Acquisition with Variable Flip Angle to Simulate and Optimized Hyperpolarized 3 He MRI with
Parallel Acquisition
Julien Rivoire 1 , Maxin Terekhov 1 , Laura Maria Schreiber 1
1 Department of Diagnostic and Interventional Radiology, Section of Medical Physics, Johannes Gutenberg University Medical Center,
Mainz, Germany
To employ the scanner’s software computational capabilities and to simulate the complete measurement process without using expensive hyperpolarized gas,
we developed the dedicated 1 H MRI acquisition protocol using variable flip angle pulse sequence to simulate hyperpolarized magnetization decay. The
protocol was used to study the effect of different space sampling ordering on images acquired with parallel acquisition techniques. Via the calculation of
point-spread-function, the effects of the trajectories were quantitatively compared.
2576. Hyperpolarized Steady-State Free Precession with Variable Flip Angles (BSSFP-VFA)
Martin H. Deppe 1 , Jim M. Wild 1
1 Academic Radiology, University of Sheffield, Sheffield, Yorkshire, United Kingdom
In imaging of hyperpolarized nuclei, balanced Steady-State Free Precession (bSSFP) sequences present a high SNR alternative to the most commonly used
Spoiled Gradient Echo (SPGR) sequences. Because hyperpolarized nuclei are not at thermal equilibrium, the longitudinal magnetization does not recover
during an imaging experiment, but decays to a negligible value with T 1 . This work presents analytical expressions for variable flip angle schedules that
maintain constant transverse magnetization, optimizing the effective k-space filter imposed by decay of hyperpolarization, and hence reducing image
blurring. The validity of the obtained expression is demonstrated in phantom experiments.
2577. High-Efficiency Continuous Production of Hyperpolarized 129 Xe Using Line-Narrowed Diode Lasers
and Optimized Cell for High Concentration of Optically Pumped Rubidium
Mineyuki Hattori 1 , Takashi Hiraga 2 , Morio Murayama 3 , Norio Ohtake 3
1 Photonics, AIST, Tsukuba, Ibaraki, Japan; 2 Photonics, AIST, Ikeda, Osaka, Japan; 3 Toyoko Kagaku Co., Ltd., Kawasaki, Kanagawa,
Japan
A compact flow-through-type apparatus for the high-efficiency continuous production of hyperpolarized 129 Xe using line-narrowed diode lasers and an
optimized cell for obtaining a higher rubidium vapor concentration at a higher temperature (~220 o C) was developed.
2578. McConnell-Bloch Modeling of HyperCEST with Xenon Biosensors
Richard Matthew Ramirez 1 , Todd K. Stevens 1 , Monica A. Smith 2 , David E. Wemmer 1 , Alexander Pines 1
1 Department of Chemistry, University of California, Berkeley, Berkeley, CA, United States; 2 Biophysics Graduate Group, University
of California, Berkeley, Berkeley, CA, United States
The McConnell-Bloch equations were modified to account for the use of hyperpolarized xenon, and then applied to fit experimental data obtained from
hyperCEST experiments in which Xe exchanges into and out of a supramolecular host. A variety of physical parameters were tested and rate constants for
the reversible exchange were determined, which are important in determining the amount of contrast generated from these agents.
2579. Metastability Exchange Optical Pumping of 3He at 1.5T for a In-Situ Polariser
guilhem Collier 1 , Anna Nikiel 1 , Tadeusz Palasz 1 , Bartek Glowacz 1 , Mateusz Suchanek 2 , Zbigniew
Olejniczak 3 , Tomasz Dohnalik 1
1 M. Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Malopolska, Poland; 2 Department of Physics, Agricultural
University, Krakow, Poland; 3 Institute of Nuclear Physics, Polish Academy of Sciences, Krakow
The feasibility of building an in situ high field polariser of 3He using the Metastability Exchange Optical Pumping (MEOP) technique is studying here. The
first results obtained with different closed cells of 3He show the possibility to produce hyperpolarised gas up to 30% at 267 mbar and 67% at 32 mbar with a
volume nagnetization production never obtained yet.
2580. Pressure Dependent Signal Enhancement in Hyper-CEST
Wolfgang Kilian 1 , Lorenz Mitschang 1 , Christian Freund 2 , Andreas Schlundt 2
1 Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany; 2 Leibnizinstitut für Molekulare
Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125 Berlin, Germany
The so called hyper-CEST method promises tremendous potential on molecule-specific MR imaging using hyperpolarized 129 Xe caged in functionalized
cryptophane cages. Here we present a model which allows for an optimization of the hyper-CEST sensitivity in biosensor applications, by variation of the
xenon concentration in the solution. To evaluate the model we have performed hyper-CEST measurements on samples with 5 μM and 0.5 μM biosensor
concentrations and varied the dissolved xenon concentration. This comparison shows that 50 nM biosensor concentrations should be detectable within a
volume of 1 ml with high sensitivity.