ELECTRONIC POSTER - ismrm

14:30 3450. Functional Magnetic Resonance Imaging Using Super-Resolved Spatially-Encoded
MRI
Noam Ben-Eliezer 1 , Ute Goerke 2 , Michael Garwood 2 , Lucio Frydman 1
1 Chemical Physics, Weizmann Institute of Science, Rehovot, Israel; 2 Center for Magnetic Resonance Research,
Radiology, University of Minnesota, Minneapolis, MN, United States
The sensitivity and specificity needed to detect neuronal activation is affected by the type of fMRI sequence and reconstruction
algorithm used. Recent development of a new single-scan imaging scheme provides an alternative fMRI tool, based on spatial
encoding, which offers higher robustness to B0 field inhomogeneities. A new post-processing procedure was combined onto this
scheme based on super-resolution image reconstruction algorithms, which improves the ensuing spatial-resolution while reducing the
initially higher hardware requirements and SAR constraints. We analyze the performance afforded by super-resolution using two
novel spatially-encoded based sequences for human fMRI studies, as compared to standard EPI.
15:00 3451. Rapid Full-Brain FMRI with Multi-Shot 3D EPI Accelerated with UNFOLD and
GRAPPA
Onur Afacan 1,2 , Dana Brooks 2 , Scott Hoge 1 , Istvan A. Morocz 1
1 Dept. of Radiology, Harvard Medical School & Brigham and Women's Hospital, Boston, MA, United States;
2 ECE Dept., Northeastern University, Boston, MA, United States
Cognitive imaging desires both whole brain coverage, relatively high spatial resolution, and high temporal resolution. In an effort to
achieve these goals with multi-shot 3D-EPI, we implemented: i) UNFOLD (in the slice encoding direction) and ii) Parallel imaging (in
both the 3D slice and phase encoding directions). We decreased the volume TR from 3s to 0.82s. We demonstrate the results on
healthy volunteer subjects using two different fMRI paradigms: a) event related complex cognitive stimuli where the events lasted for
a time period of up to twenty TRs and b) a simple visuospatial-motor task in a random-length block design.
Thursday 13:30-15:30 Computer 21
13:30 3452. Event-Related Whole-Brain FMRI: EPI with Slice Dependent Echo Times Versus
Standard EPI
Sebastian Domsch 1 , Julia Linke 2 , Michaela Ruttorf 1 , Michele Wessa 2 , Lothar Rudi Schad 1
1 Department of Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany;
2 Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Mannheim, Germany
We present an event-related whole-brain fMRI study at 3T testing an EPI with slice dependent TE (modified EPI) against an EPI with
TE of 27ms (standard EPI). Twelve subjects performed a learning task, which predominantly involved limbic and frontal brain
regions. The number of supra-threshold voxels found in putamen, thalamus, parahippocampal gyrus, hippocampus and superior frontal
cortex is more than twice as great in the modified EPI as compared to the standard EPI. More activation is found in the middle frontal
gyrus and the olfactory cortex using the standard EPI. Maximal Z-scores are slightly higher in most regions when using the modified
EPI.
14:00 3453. Accelerated Three-Dimensional Z-Shimming for FMRI
Jung-Jiin Hsu 1 , Gary H. Glover 2
1 Department of Radiology, University of Miami School of Medicine, Miami, FL, United States; 2 Lucas Center
for Imaging, Stanford University, Stanford, CA, United States
Z-shimming is an effective method to mitigate the signal loss caused by through-slice magnetic field inhomogeneity and is
conventionally implemented by two-dimensional imaging. When z-shimming is implemented with three-dimensional imaging, more
z-shims are available to reconstruct images of higher quality. In this work, we show that accelerated three-dimensional z-shimming by
partial k-space acquisition can significantly increase the number of available z-shims and improve temporal resolution for fMRI
without activation detectablility being compromised.
14:30 3454. Automatic Z-Shimming Based on a Real-Time Feedback Optimization Framework
in BOLD-EPI
Yu-Wei Tang 1 , Teng-Yi Huang 1
1 Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
Z-shimming is a useful method for correcting the susceptibility-induced signal losses in BOLD-EPI. For seeking the best z-shim
images for compensating the lost signal, an automatic real time z-shimming method was proposed in this study. By implementing a
feedback loop between the scanner and a PC through network connection, the best z-shim value could be converged by the
optimization algorithm. In conclusion, our method not only can amend the signal losses problem successfully but also provide rapider
searching time and higher accuracy of optimal z-shim value.