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Q: Fachverband Quantenoptik und Photonik

Q 65: Quantum Information (Miscellaneous)

Q 65.6: Talk

Friday, March 18, 2022, 11:45–12:00, Q-H12

Optimal control design of preparation pulses for higher contrast imaging — •Amanda Nicotina and Steffen Glaser — Technische Universität München, Munich, Germany

Magnetic Resonance Imaging (MRI) is an imaging technique that has gained a lot of attention in the medical community for its ability to visualize the internal body in a non-invasive manner. This visualization is achieved based on the contrast originating from intrinsic tissue properties, such as relaxation times (T1 and T2). This contrast can be emphasized via additional acquisition parameters (for example, flip angles/RF pulses), the standard acquisition strategies being T1 and T2 weighting. However, these do not always generate the optimal contrast. This work proposes a more tailored approach, where we present how to find an optimal sequence of flip angles based on optimal control theory for the contrast between specific tissues. In addition, it allows for robust control pulses even when introducing B0- and B1-inhomogeneities. More precisely, we employ the Pontryagin Maximum Principle to numerically find optimal solutions to the underlying Bloch equations implementing the GRadient Ascent Pulse Engineering (GRAPE) algorithm. In particular, we focus on the theoretical and experimental limits of the optimizations.