Spoke pulse design in magnetic resonance imaging using greedy minimax algorithm

Spoke RF pulse design in MRI requires joint optimization of the k-space trajectory and RF pulse weights. This design task is often modelled as a sparse approximation problem with a cost function evaluating the l 2 norm of the excitation error, which can be approximately solved using the orthogonal m...

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Bibliographic Details
Main Authors: Hao Sun, Weller, Daniel S., Chu, Alan, Ramani, Sathish, Daehyun Yoon, Nielsen, Jon-F, Fessler, Jeffrey A.
Format: Conference Proceeding
Language:English
Subjects:
Algorithm design and analysis
Approximation algorithms
Approximation methods
Cost function
l ∞ norm
Matching pursuit algorithms
minimax
Minimization
OMP
Radio frequency
RF shimming
spoke pulse
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Summary:Spoke RF pulse design in MRI requires joint optimization of the k-space trajectory and RF pulse weights. This design task is often modelled as a sparse approximation problem with a cost function evaluating the l 2 norm of the excitation error, which can be approximately solved using the orthogonal matching pursuit (OMP) algorithm. However, l 2 optimization does not strictly regulate a maximum deviation between excitation and desired patterns, and may leave bright or dark spots in the image. In this paper, we model the pulse design problem as a sparse approximation problem with an l ∞ norm cost function, and propose a greedy algorithm for solving this new problem. Simulation results demonstrate that our algorithm can produce improved spoke RF pulses (reduced maximum error) compared to l 2 optimization.
ISSN:1945-7928
1945-8452
DOI:10.1109/ISBI.2013.6556570