Time-optimal control of the Bloch equations in magnetic resonance imaging
Karl Kunisch and Armin Rund (in cooperation with Christoph Aigner and Rudolf Stollberger, Institute of Medical Engineering, TU Graz)
To contribute to the reduction of scanning times in Magnetic Resonance Imaging (MRI),
a time-optimal control problem for the Bloch equations is introduced.
Focus is the optimal excitation/refocusing of the nuclear magnetization in minimum time.
Technical restrictions of the scanner device are modeled as inequality constraints.
A numerical optimal control software is designed, implemented and the code is parallelized on HPC clusters.
The code is tested on realistic examples for typical spin echo based sequences. The optimization results
are implemented on a 3T scanner device and tested in phantom and in-vivo measurements.
The code won the international contest on simultaneous multi-slice refocusing,
hosted by the International Society for Magnetic Resonance in Medicine (ISMRM).
