Joint Annual Meeting ISMRM-ESMRMB 2014 10-16 May 2014 Milan, Italy

Multi-Band Methods

Wednesday 14 May 2014
Space 2  16:00 - 18:00 Moderators: Steen Moeller, Ph.D., Kawin Setsompop, Ph.D.

16:00 0642.   Stack-of-Spirals CAIPIRINHA Trajectory for Rapid Volumetric Imaging
Weiran Deng1, Benjamin Zahneisen1, and V. A. Stenger1
1University of Hawaii, John A. Burns School of Medicine, Honolulu, HI, United States

This abstract presents a CAIPIRINHA style sampling using a 3D stack-of-spiral trajectory. By rotating the spiral interleaves along the through-plane direction, the encoding capability of the receiver sensitivities can be better used to improve the g-factor. We show the improved quality of the 3T in vivo human brain images acquired at 2multiplication sign0.75multiplication sign0.75mm3 resolution using this method. In addition, this abstract presents a 3D GRAPPA method that is used to reconstruct the CAIPIRINHA style under-sampled stack-of-spiral data.

16:12 0643.   
Whole brain fMRI in 370ms: exploring the benefits of high temporal resolution 3D-EPI-CAIPI
Mayur Narsude1,2, Daniel Gallichan3, Wietske van der Zwaag3, Rolf Gruetter3, and Jose Marques3
1LIFMET, EPFL, Lausanne, Vaud, Switzerland, 2University of Lausanne, Lausanne, Vaud, Switzerland, 3CIBM, EPFL, Lausanne, Vaud, Switzerland

This study aimed to demonstrate benefit of highly accelerated 3D-EPI-CAIPI wholebrain fMRI, particularly the ability to filter out respiratory and cardiac noise. Thanks to the use of 3D-EPI-CAIPI sampling patterns, it was possible obtain a 3 and 8 fold increases in temporal resolution in respect to un-accelerated 3D-EPI with only mild g-factor penalty. Temporal SNR per unit of time of the 8-fold accelerated data was ~62% and ~26% higher than un-accelerated and 3-fold accelerated data respectively. Better physiological signals filtering with higher sampling rates resulted in higher statistical significance for resting state networks found via Independent Component Analysis.

16:24 0644.   Motion Insensitive ACS Acquisition Method for in-plane and Simultaneous Multi-Slice Accelerated EPI
Himanshu Bhat1, Jonathan R. Polimeni2, Stephen F. Cauley2, Kawin Setsompop2, Lawrence L. Wald2, and Keith Heberlein1
1Siemens Medical Solutions USA Inc, Charlestown, MA, United States, 2Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States

Conventional ACS sampling methods for in-plane and simultaneous multi-slice accelerated EPI are susceptible to physiological or bulk subject motion. In this work we propose a novel motion-insensitive ACS acquisition technique called FLEET for highly accelerated EPI. The performance of both conventional and FLEET ACS sampling is evaluated with tSNR analysis done with and without deliberate head nodding performed during ACS acquisition. The conventional method and FLEET give comparable results without motion, however the FLEET method performs better in the presence of motion during the ACS scan.

16:36 0645.   
Optimizing CAIPIRINHA multi-band acquisition scheme for 2D multi-slice experiments in the abdomen
Bjorn Stemkens1, Rob H. Tijssen1, Anna Andreychenko1, Sjoerd P.M. Crijns1, Alessandro Sbrizzi2, Jan J.W. Lagendijk1, and Cornelis A.T. van den Berg1
1Department of Radiotherapy, UMC Utrecht, Utrecht, Netherlands, 2Department of Radiology, UMC Utrecht, Utrecht, Netherlands

Multi-slice CAIPIRINHA can accelerate clinical abdomen scans significantly by exciting multiple slices simulatenously. In this study we determine the optimal shift pattern and slice gap to improve reconstruction and quantify its reproducibility.

16:48 0646.   Multi-Band-Multi-Spoke pTX RF Pulse Design in the Heart at 7 Tesla: towards Faster, Uniform Contrast Cardiac CINE Imaging
Sebastian Schmitter1, Xiaoping Wu1, Steen Moeller1, Dingxin Wang1,2, Andreas Greiser3, Edward J. Auerbach1, Lance DelaBarre1, Pierre-Francois van de Moortele1, and Kamil Ugurbil1
1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States, 2Siemens Medical Solutions USA, Inc., Minneapolis, MN, United States, 3Siemens Healthcare Sector, Erlangen, Bavaria, Germany

Cardiac MRI may strongly benefit from ultra-high field (UHF) providing higher SNR and intrinsic contrast. However, shorter RF wavelength at UHF results in heterogeneous contrast within the heart. This problem has been successfully addressed with parallel transmission (pTX) using 3D tailored RF excitation ('spokes'). Additionally, respiratory motion often requires breath-hold examinations, which strongly limits spatial coverage. Here we address simultaneously spatial coverage and homogeneity by designing pTX spoke pulses to simultaneously excite/acquire multiple slices ('Multi-Band') using a 16-channel pTX system. We demonstrate successful cardiac CINE multiband acquisitions for 2 slices at 7T and compare 1- and 2-spoke pulse performances.

17:00 0647.   Nyquist Ghosting Correction For Simultaneous Multislice Echo Planar Imaging
Kangrong Zhu1, Robert F. Dougherty1, Atsushi M. Takahashi2, John M. Pauly1, and Adam B. Kerr1
1Stanford University, Stanford, CA, United States, 2Athinoula A. Martinos Imaging Center at MIT, McGovern Institute for Brain Research, MIT, MA, United States

In simultaneous multislice (SMS) EPI the ghosting artifacts cannot be accurately corrected in each individual slice if the correction is performed independently of the slice unaliasing. In this work a SMS acquisition is represented as a 3D k-space acquisition, where the kx dimension is fully sampled and the ky-kz plane is undersampled. Eddy current effects that lead to the ghosting artifacts are treated as part of the encoding matrix, allowing both slice unaliasing and eddy current effects to be simultaneously and accurately corrected for with the proposed matrix-decoding method. Parallel imaging reconstruction is also incorporated in the proposed method.

17:12 0648.   Increasing parallel imaging performance and correcting field inhomogeneity artifact in MS-CAIPIRINHA using view angle tilting technique (CAIPI-VAT)
Min-Oh Kim1, Taehwa Hong1, and Dong-Hyun Kim1
1Electrical and Electronic Engineering, Yonsei University, Seoul, Seoul, Korea

Reducing parallel imaging penalty and increasing its acceleration capability by combining two techniques, CAIPIRINHA and View angle tilting.

17:24 0649.   Multi-Band-SWIFT
Djaudat Idiyatullin1, Curtis A. Corum1, and Michael Garwood1
1Radiology, CMRR, University of Minnesota, Minneapolis, MN, United States

This work describes an enhancement of the gapped SWIFT (SWeep Imaging with Fourier Transformation) method utilizing multiple sidebands to achieve highly increased excitation and acquisition bandwidth. The method is called Multi-Band-SWIFT (or MB-SWIFT). Due to its tailored (striped) excitation pattern, MB-SWIFT efficiently uses transmitter power and has increased sensitivity as compared to the other techniques used for “ultrashort TE” imaging. Additionally, MB-SWIFT provides a way to obtain additional information about fast and slow relaxing spins in a single scan. These features make MB-SWIFT an attractive method for numerous MRI applications including musculoskeletal imaging.

17:36 0650.   Multiband RF Excitation for Accelerating Magnetic Resonance Imaging in the Presence of Metal
Nathan Artz1, Matthew Smith1, and Scott Reeder1,2
1Radiology, University of Wisconsin, Madison, WI, United States, 2Medicine, University of Wisconsin, WI, United States

The purpose of this work was to develop and test multiband RF excitation to accelerate a fully phase encoded (FPE) technique when multiple RF excitations are required to excite a wide range of off-resonance near metallic implants. The femoral head of a hip prosthesis was placed in water and three separate scans were performed with a single RF band, each centered at a different RF offset (-4000, 0, +4000 Hz). The fourth scan used the MB RF pulse to excite all three RF bands simultaneously. This work demonstrates feasibility for reducing scan time using MB excitation near metal with FPE methods.

17:48 0651.   (2+1)D-CAIPIRINHA Accelerated FID Based MRSI of the Brain at 7T
Bernhard Strasser1, Gilbert Hangel1, Marek Chmelík1, Siegfried Trattnig1, Stephan Gruber1, Michal Považan1, and Wolfgang Bogner1
1High Field MR Centre, Department of Biomedical Imaging und Image-guided Therapy, Medical University of Vienna, Vienna, Vienna, Austria

In this work the parallel imaging methods slice-Caipirinha and 2D-Caipirinha were combined to (2+1)D-Caipirinha in order to simulate an acceleration of two-slice Hadamard encoded MRSI data of the brain at 7T. The proposed method was compared to standard in-plane acceleration and a reconstruction using 2D-GRAPPA. (2+1)D-Caipirinha was shown to be superior over the standard 2D-GRAPPA acceleration. The original 60 minutes scan could have been reduced with an acceleration factor of 8.7 to clinically relevant scan times of 7 minutes, while still providing enough SNR to quantify tNAA, tCho and tCr.