High field MRI (3T, 7T and above) offers many potential advantages to clinical and scientific studies, including increased sensitivity and improved image contrast creating the potential for improved characterization of biological function and anatomy in health and disease. Parallel transmission (pTx) uses multiple excitation coils driven by independent RF pulse waveforms to subdivide the transmit field into multiple spatial regions each controlled by a separate transmit channel. Increasing the number of spatially distinct transmit elements and using temporally distinct RF pulse waveforms creates spatial degrees of freedom that allow the spatial pattern of the array to be exploited in the excitation process. Previous pTx work by ourselves and others has concentrated on the potential to utilize this additional flexibility to move beyond the uniform slice-select excitation. In the current proposal, we propose a program of translational bioengineering development to widely impact 3T clinical imaging and facilitate the advance of 7T clinical imaging by develop and validate novel methods to increase the degrees of freedom available in pTx pulse design together with novel optimization schemes which can convert these degrees of freedom into reduced SAR. Successful implementation of such methods potentially allow us to expand the quality of clinical imaging by providing more slices, higher flip angles, or shorter TR periods in a wide range of clinical protocols. Additionally we will develop methods which directly address the local SAR problems of the more exotic 2D and 3D spatially tailored pulses, which has proven to be a major limitation of these pulses. Finally we provide a theoretical and experimental validation of the SAR models in ubiquitous use.

Public Health Relevance

This bioengineering project seeks to develop translational technology to improve Magnetic Resonance Imaging (MRI). Its ultimate goal is to provide improve the MR images used for clinical diagnosis of disease and to increase the ability of MR as a scientific tool for studying anatomy and function within the living human body in health and disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
2R01EB006847-05A1
Application #
8236238
Study Section
Biomedical Imaging Technology Study Section (BMIT)
Program Officer
Liu, Guoying
Project Start
2006-12-01
Project End
2015-08-31
Budget Start
2011-09-15
Budget End
2012-08-31
Support Year
5
Fiscal Year
2011
Total Cost
$459,790
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
02199
Vinding, Mads S; Guérin, Bastien; Vosegaard, Thomas et al. (2017) Local SAR, global SAR, and power-constrained large-flip-angle pulses with optimal control and virtual observation points. Magn Reson Med 77:374-384
Golestanirad, Laleh; Iacono, Maria Ida; Keil, Boris et al. (2017) Construction and modeling of a reconfigurable MRI coil for lowering SAR in patients with deep brain stimulation implants. Neuroimage 147:577-588
Golestanirad, Laleh; Keil, Boris; Angelone, Leonardo M et al. (2017) Feasibility of using linearly polarized rotating birdcage transmitters and close-fitting receive arrays in MRI to reduce SAR in the vicinity of deep brain simulation implants. Magn Reson Med 77:1701-1712
Mahmood, Zohaib; McDaniel, Patrick; Guérin, Bastien et al. (2016) General design approach and practical realization of decoupling matrices for parallel transmission coils. Magn Reson Med 76:329-39
Guérin, Bastien; Stockmann, Jason P; Baboli, Mehran et al. (2016) Robust time-shifted spoke pulse design in the presence of large B0 variations with simultaneous reduction of through-plane dephasing, B1+ effects, and the specific absorption rate using parallel transmission. Magn Reson Med 76:540-54
Tian, Qiyuan; Rokem, Ariel; Folkerth, Rebecca D et al. (2016) Q-space truncation and sampling in diffusion spectrum imaging. Magn Reson Med 76:1750-1763
Davids, Mathias; Schad, Lothar R; Wald, Lawrence L et al. (2016) Fast three-dimensional inner volume excitations using parallel transmission and optimized k-space trajectories. Magn Reson Med 76:1170-82
Huang, Susie Y; Tobyne, Sean M; Nummenmaa, Aapo et al. (2016) Characterization of Axonal Disease in Patients with Multiple Sclerosis Using High-Gradient-Diffusion MR Imaging. Radiology 280:244-51
Villena, Jorge Fernandez; Polimeridis, Athanasios G; Eryaman, Yigitcan et al. (2016) Fast Electromagnetic Analysis of MRI Transmit RF Coils Based on Accelerated Integral Equation Methods. IEEE Trans Biomed Eng 63:2250-2261
Martin, Adrian; Schiavi, Emanuele; Eryaman, Yigitcan et al. (2016) Parallel transmission pulse design with explicit control for the specific absorption rate in the presence of radiofrequency errors. Magn Reson Med 75:2493-504

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