Comparison of simulated parallel transmit body arrays at 3 T using excitation uniformity, global SAR, local SAR, and power efficiency metrics

We compare the performance of eight parallel transmit (pTx) body arrays with up to 32 channels and a standard birdcage design. Excitation uniformity, local specific absorption rate (SAR), global SAR, and power metrics are analyzed in the torso at 3 T for radiofrequency (RF)‐shimming and 2‐spoke excitations.

[1]  Matthias M. Müller,et al.  The use of principal component analysis (PCA) for estimation of the maximum reduction factor in 2D parallel imaging , 2005 .

[2]  Gabriele Eichfelder,et al.  Local specific absorption rate control for parallel transmission by virtual observation points , 2011, Magnetic resonance in medicine.

[3]  D. Sodickson,et al.  Ideal current patterns yielding optimal signal‐to‐noise ratio and specific absorption rate in magnetic resonance imaging: Computational methods and physical insights , 2012, Magnetic resonance in medicine.

[4]  R. Turner,et al.  Effects of tuning condition, head size and position on the SAR of a MRI dual-row transmit array at 400MHz , 2013 .

[5]  Robert Turner,et al.  Fast MRI coil analysis based on 3-D electromagnetic and RF circuit co-simulation. , 2009, Journal of magnetic resonance.

[6]  F. Seifert,et al.  Current CONtrolled Transmit And Receive Coil Elements (C2ONTAR) for Parallel Acquisition and Parallel Excitation Techniques at High-Field MRI , 2011, Applied magnetic resonance.

[7]  Lawrence L. Wald,et al.  An Automated Framework to Decouple pTx Arrays with Many Channels , 2012 .

[8]  E. Adalsteinsson,et al.  Magnitude least squares optimization for parallel radio frequency excitation design demonstrated at 7 Tesla with eight channels , 2008, Magnetic resonance in medicine.

[9]  D. Sodickson,et al.  Approaching ultimate SNR and ideal current patterns with finite surface coil arrays on a dielectric cylinder , 2008 .

[10]  Robert Turner,et al.  Optimization of geometry for a dual-row MRI array at 400 MHz , 2013, IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications.

[11]  Douglas C. Noll,et al.  Tuning ultra-low output impedance amplifiers for optimal power and decoupling in parallel transmit MRI , 2013, 2013 IEEE 10th International Symposium on Biomedical Imaging.

[12]  Whole Grain Label Statements.  Guidance for Industry and FDA Staff , 2006 .

[13]  Elfar Adalsteinsson,et al.  Local SAR in parallel transmission pulse design , 2011, Magnetic resonance in medicine.

[14]  D. Sodickson,et al.  Electrodynamic constraints on homogeneity and radiofrequency power deposition in multiple coil excitations , 2009, Magnetic resonance in medicine.

[15]  Robert Turner,et al.  Analysis of RF transmit performance for a multi-row multi-channel MRI loop array at 300 and 400 MHz , 2011, Asia-Pacific Microwave Conference 2011.

[16]  Alessandro Sbrizzi,et al.  Fast design of local N‐gram‐specific absorption rate–optimized radiofrequency pulses for parallel transmit systems , 2012, Magnetic resonance in medicine.

[17]  Stephen P. Boyd,et al.  Convex Optimization , 2004, Algorithms and Theory of Computation Handbook.

[18]  R. Turner,et al.  Optimization of a near-field array , 2012, 2012 Asia Pacific Microwave Conference Proceedings.

[19]  Reinhold Ludwig,et al.  A numerical postprocessing procedure for analyzing radio frequency MRI coils , 2011 .

[20]  Ferdinand Schweser,et al.  Local SAR constrained Hotspot Reduction by Temporal Averaging , 2009 .

[21]  Kawin Setsompop,et al.  Parallel RF transmission with eight channels at 3 Tesla , 2006, Magnetic resonance in medicine.

[22]  Yudong Zhu,et al.  Parallel excitation with an array of transmit coils , 2004, Magnetic resonance in medicine.

[23]  Douglas C Noll,et al.  Spatial domain method for the design of RF pulses in multicoil parallel excitation , 2006, Magnetic resonance in medicine.

[24]  Markus Vester,et al.  Degenerate mode band‐pass birdcage coil for accelerated parallel excitation , 2007, Magnetic resonance in medicine.

[25]  Daniel D. Dilks,et al.  Size‐optimized 32‐channel brain arrays for 3 T pediatric imaging , 2011, Magnetic resonance in medicine.

[26]  I. Graesslin,et al.  Comprehensive RF Safety Concept for Parallel Transmission Systems , 2007 .

[27]  L. Wald,et al.  A 64‐channel 3T array coil for accelerated brain MRI , 2013, Magnetic resonance in medicine.

[28]  Klaus Scheffler,et al.  A 16‐channel dual‐row transmit array in combination with a 31‐element receive array for human brain imaging at 9.4 T , 2014, Magnetic resonance in medicine.

[29]  Herbert Rinneberg,et al.  Patient safety concept for multichannel transmit coils , 2007, Journal of magnetic resonance imaging : JMRI.

[30]  Joseph V. Hajnal,et al.  Impact of number of channels on RF shimming at 3T , 2013, Magnetic Resonance Materials in Physics, Biology and Medicine.

[31]  Vivek K Goyal,et al.  Specific absorption rate studies of the parallel transmission of inner‐volume excitations at 7T , 2008, Journal of magnetic resonance imaging : JMRI.

[32]  Lawrence L. Wald,et al.  Local specific absorption rate (SAR), global SAR, transmitter power, and excitation accuracy trade‐offs in low flip‐angle parallel transmit pulse design , 2014, Magnetic resonance in medicine.

[33]  Ferdinand Schweser,et al.  SAR in Parallel Transmission , 2008 .

[34]  Kyle M Gilbert,et al.  A radiofrequency coil to facilitate B  1+ shimming and parallel imaging acceleration in three dimensions at 7 T , 2011, NMR in biomedicine.

[35]  J. Polimeni,et al.  96‐Channel receive‐only head coil for 3 Tesla: Design optimization and evaluation , 2009, Magnetic resonance in medicine.