TRADITIONAL POSTER - ismrm

Poster Sessions
962. Correction of Eddy Currents for Time-Domain-Interleaved Blipped-Phase-Encoding Echo-Planar
Spectroscopic Imaging
Yoshitaka Bito 1 , Koji Hirata 1 , Satoshi Hirata 1 , Toru Shirai 1 , Toshihiko Ebisu 2 , Yuko Kawai 3 , Yosuke
Otake 1 , Yoshihisa Soutome 1 , Hisaaki Ochi 1 , Masahiro Umeda 3 , Toshihiro Higuchi 4 , Chuzo Tanaka 4
1 Central Research Laboratory, Hitachi, Ltd., Kokubunji-shi, Tokyo, Japan; 2 Neurosurgery, Nantan General Hospital, Nantan-shi,
Kyoto, Japan; 3 Medical Informatics, Meiji University of Integrative Medicine, Nantan-shi, Kyoto, Japan; 4 Neurosurgery, Meiji
University of Integrative Medicine, Nantan-shi, Kyoto, Japan
High-speed spectroscopic imaging using the echo-planar technique is sometimes distorted by eddy currents. We developed an eddy current correction
technique for time-domain-interleaved blipped-phase-encoding echo-planar spectroscopic imaging (TDI-BPE-EPSI). This technique uses correction of
spatial shift due to chemical shifts in the blipped-phase-encoding direction before applying eddy current correction based on the water signal. Correction of
eddy currents is demonstrated by applying this technique to a phantom and a rat brain in vivo. This technique is shown to be also useful in diffusionweighted
spectroscopic imaging, which causes more eddy currents due to strong diffusion gradients.
963. Comparison of Automatic and Manual Prescription Protocols for Brain 3D MRSI
Eugene Ozhinsky 1,2 , Daniel B. Vigneron 1,3 , Susan M. Chang 4 , Sarah J. Nelson 1,3
1 Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San
Francisco, San Francisco, CA, United States; 2 UCSF/UCB Joint Graduate Group in Bioengineering, University of California, San
Francisco, San Francisco, CA, United States; 3 Department of Bioengineering and Therapeutic Sciences, University of California, San
Francisco, San Francisco, CA, United States; 4 Department of Neurological Surgery, University of California, San Francisco, San
Francisco, CA, United States
In this work we have evaluated the coverage volume and data quality of 3D MRSI protocols with manual and automatic prescription of outer-volume
suppression and selected volume. Automatic oblique prescription allowed approximately 3x increase in coverage volume with no decline in data quality.
964. Inductively Coupled Reference Signal Injection Method for Quantitative MRI
Donghoon Lee 1 , Kenneth Marro 1 , Mark Mathis 1 , Cecil Hayes 1
1 University of Washington, Seattle, WA, United States
We report our efforts on continuous development of a synthetic signal injection method for metabolite quantification using MRS and MRI. This work
demonstrates that calibrated synthetic voxels (instead of pseudo-FID: free induction decay), injected during or separately from real image acquisition, can be
used to quantify metabolite content in real 19F image voxels. Images of vials containing different concentrations of sodium fluoride (NaF) were converted to
units of moles by reference to precalibrated synthetically-injected voxels. Additional images of vials containing variable sodium chloride (NaCl)
demonstrate that the quantification process is robust and immune to changes in coil loading conditions.
965. Iterative CSI Reconstruction with High-Resoluiton Spatial Priors for Improved Lipid Suppression
Joonsung Lee 1 , Elfar Adalsteinsson 1,2
1 Electrical engineering and computer science, Massachusetts Institute of Technology, Cambridge, MA, United States; 2 Harvard-MIT
Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States
We have developed and demonstrated an iterative reconstruction with spatial priors for improved lipid suppression. By imposing the spatial locality
constraint on the lipid spectra inside the brain, we are able to substantially improve lipid suppression from the subcutaneous fat into the brain.
966. Skewed Adiabatic Pulses for Outer Volume Suppression in Single Voxel Spectroscopy
Federico Giove 1,2 , Francesco Marcocci 1 , Fabrizio Fasano, 1,3 , Mauro DiNuzzo 1 , Gisela E. Hagberg 3 ,
Bruno Maraviglia 1,2
1 Department of Physics, Sapienza University of Rome, Rome, RM, Italy; 2 MARBILab, Enrico Fermi Center, Rome, RM, Italy;
3 Neuroimaging Laboratory, Fondazione Santa Lucia IRCCS, Rome, RM, Italy
We developed an outer volume suppression approach for nulling the external signal in single voxel spectroscopy, based on trains of adiabatitic skewed
selective pulse. The pulses shape allowed the saturation bands to be prescribed adjacent to the voxel, without loss of signal. The train was tested before
STEAM and PRESS acquisition schemes at 3T, and showed excellent performaces both in vitro and in vivo, in particolar for the suppression of exravoxel
lipids in the visual cortex. Optimal performances were observed with VAPOR water suppression and short TE STEAM, but the approach worked eqaully
well before PRESS at intermediate (30ms) TE
967. Atlas-Based Automated Positioning of Outer Volume Suppression Slices in Short-TE 3D MR
Spectroscopic Imaging of the Human Brain
Kaung-Ti Yung 1 , Chenguang Zhao 1 , Weili Zheng 1 , Manel Martinez-Ramon 2 , Andre van der Kouwe 3 , Stefan
Posse 1,4
1 Neurology, University of New Mexico School of Medicine, Albuquerque, NM, United States; 2 Dept. of Signal Processing and
Communications, Universidad Carlos III de Madrid, Madrid, Spain; 3 Radiology, Massachusetts General Hospital, Boston, MA, United
States; 4 Electrical and Computer Engineering, University of New Mexico, Albuquerque, NM, United States
Manual placement of outer volume suppression (OVS) slices in short TE proton MR spectroscopic imaging (MRSI) is time consuming and prone to human
error. Here, we introduce an atlas-based approach to optimally positions both the 3D MRSI slab and up to 16 OVS slices in a subject’s head using affine
transformation of MRSI slab and OVS slice positions that are optimally placed in MNI space. In vivo 3D short TE (11 ms) Proton-Echo-Planar-
Spectroscopic-Imaging (PEPSI) demonstrates consistent spectral quality with the MRSI volume and comparable lipid suppression for automatic and manual
OVS placement, which is desirable for clinical research studies.