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Poster
Experimental design for MRI by greedy policy search
Tim Bakker · Herke van Hoof · Max Welling

Wed Dec 09 09:00 AM -- 11:00 AM (PST) @ Poster Session 3 #977
in Poster Session 4 »

In today’s clinical practice, magnetic resonance imaging (MRI) is routinely accelerated through subsampling of the associated Fourier domain. Currently, the construction of these subsampling strategies - known as experimental design - relies primarily on heuristics. We propose to learn experimental design strategies for accelerated MRI with policy gradient methods. Unexpectedly, our experiments show that a simple greedy approximation of the objective leads to solutions nearly on-par with the more general non-greedy approach. We offer a partial explanation for this phenomenon rooted in greater variance in the non-greedy objective's gradient estimates, and experimentally verify that this variance hampers non-greedy models in adapting their policies to individual MR images. We empirically show that this adaptivity is key to improving subsampling designs.

[ Paper ]

Author Information

Tim Bakker (University of Amsterdam)
Herke van Hoof (University of Amsterdam)
Max Welling (University of Amsterdam / Qualcomm AI Research)

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