TRADITIONAL POSTER - ismrm

Poster Sessions
optimally utilizing the densely sampled low-spatial-frequency data. Individual coil images are then linearly combined using data-driven sensitivity estimates.
In vivo comparisons with PILS and SENSE are provided.
2883. Synthetic Target Combined with PILS (ST-PILS) for Improving SNR in Parallel Imaging
Meihan Wang 1 , Weitian Chen 2 , Michael Salerno 1 , Peng Hu 3 , Christopher M. Kramer 1 , Craig Meyer 1
1 Biomedical Engineering, University of Virginia, Charlottesville, VA, United States; 2 GE; 3 Beth Israel Deaconess Medical Center,
The abstract introduces a novel rapid reconstruction algorithm called ST(Synthetic Target)-PILS. It improves the original Synthetic Target method by
achieving a higher SNR. We also studied reconstruction speed comparing to coil-by-coil reconstruction.
2884. Iterative IIR GRAPPA: A Novel Improved Method for Parallel MRI
Kaiyu Zheng 1 , Wendy Ni 1 , Jingxin Zhang 2
1 Monash Unversity; 2 Department of Electrical and Computer Systems Engineering, Monash University, Clayton, VIC 3800, Australia
GRAPPA proves to be an effective constrained parallel MRI method. However, it does not exploit the acqired data to the utmost.In our investigation to
produce a superior parallel Magnetic Resonance Imaging (MRI) reconstruction technique, we propose the novel method of Infinite Impulse Response
Iterative GRAPPA (IIR iGRAPPA). This method uses both acquired and reconstructed data points to iteratively interpolate downsampled k-space data,
achieving excellent reconstruction quality without the need to acquire much additional data for calibration purposes. Experimental results clearly
demonstrate the superiority of the proposed method over the conventional GRAPPA method.
2885. Applying Parallel Imaging for SNR Enhancement
Daniel Stäb 1 , Christian Ritter 1 , Dietbert Hahn 1 , Herbert Köstler 1
1 Institute of Radiology, University of Wuerzburg, Wuerzburg, Bavaria, Germany
Typically in fast MRI, the measurements are carried out using a high readout bandwidth, leading to a generally low SNR. In this work undersampling k-
space, while maintaining the image acquisition time is proposed. Consequently, TR and the signal acquisition time can be raised and the SNR is increased.
For image reconstruction, parallel imaging techniques are utilized. As the SNR gain is considerably influenced by the geometry factor crucial investigations
are required. g-factors are minimized by homogeneously distributing the phase encoding steps over k-space. Thus, in terms of SNR, the use of additional
reference scans or techniques like TGRAPPA, TSENSE and Auto-SENSE is advantageous.
2886. Noise Weighted T 2 *-IDEAL Reconstruction for Non-Uniformly Under-Sampled k-Space Acquisitions
Curtis Nathan Wiens 1 , Shawn Joseph Kisch 2 , Catherine D. G. Hines 3 , Huanzhou Yu 4 , Angel R. Pineda 5 ,
Philip M. Robson 6 , Jean H. Brittain 7 , Scott B. Reeder, 38 , Charles A. McKenzie 1,2
1 Department of Physics and Astronomy, University of Western Ontario, London, Ont, Canada; 2 Department of Medical Biophysics,
University of Western Ontario, London, Ont, Canada; 3 Department of Biomedical Engineering, University of Wisconsin-Madison,
Madison, WI, United States; 4 Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 5 Department of
Mathematics, California State University, Fullerton, CA, United States; 6 Department of Radiology, Beth Israel Deaconess Medical
Center and Harvard Medical School, Boston, MA, United States; 7 Applied Science Laboratory, GE Healthcare, Madison, WI, United
States; 8 Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States
Using different undersampling patterns for the non-calibration and calibration echoes has been shown to improve SNR per unit time of Parallel Imaging
accelerated IDEAL reconstructions by up to 40%. The different acceleration factors and k-space undersampling patterns result in different noise
enhancement in the non-calibration and calibration echoes. In this work the T 2 *-IDEAL reconstruction is modified to include noise weighting and
demonstrate that SNR improves with the modified reconstruction. For 14.2 fold accelerated phantom data, an 11.9% increase in mean SNR for all phantoms
and a maximum 27% increase in SNR over a single phantom was measured.
2887. Three-Dimensionally Accelerated Radial Parallel MRI with a 32-Channel Coil System
Olaf Dietrich 1 , Maria Suttner 1 , Maximilian F. Reiser 1
1 Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU Ludwig Maximilian University of
Munich, Munich, Germany
Established parallel-imaging techniques include the one-dimensional or two-dimensional acceleration of the data acquisition with Cartesian or non-Cartesian
trajectories. However, state-of-the-art receiver coil arrays with 32 and more coil elements that are distributed approximately uniformly in space should also
enable a three-dimensional parallel-imaging acceleration, i.e. simultaneous sparse sampling in all three k-space directions. The purpose of this study was to
demonstrate three-dimensional parallel-imaging acceleration with high acceleration factors up to 32 based on a three-dimensional radial gradient-echo
sequence.
2888. A Rapid Self-Calibrating Radial GRAPPA Method Using Kernel Coefficient Interpolation
Noel C. Codella 1 , Pascal Spincemaille 2 , Martin Prince 2 , Yi Wang 2
1 Physiology, Cornell Weill Medical College, New York, NY, United States; 2 Radiology, Cornell Weill Medical College
This work proposes a rapid self-calibrating radial GRAPPA method that eliminates the need to change domains, calculate sensitivity maps, generate
synthetic calibration data, or perform extra gridding operations before the derivation of the GRAPPA kernels.
2889. Zoomed GRAPPA (ZOOPPA) for Functional MRI
Robin Martin Heidemann 1 , Dimo Ivanov 1 , Robert Trampel 1 , Fabrizio Fasano 2 , Josef Pfeuffer 3 , Robert
Turner 1
1 Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 2 Fondazione Santa Lucia, Rome, Italy; 3 Siemens
Healthcare Sector, Erlangen, Germany
The increased SNR of ultra-high field MR scanners permits improved resolution of fMRI acquisitions. Unfortunately, both high field and high resolution
amplify artifacts such as geometric distortions and blurring. Parallel imaging and zoomed imaging can each mitigate these effects. However, highly