Improving Magnetic Resonance Imaging with Smart and Thin Metasurfaces

TL;DR

This paper introduces a thin, self-tuning metamaterial that significantly enhances MRI signal quality without compromising safety, enabling more effective and patient-specific imaging solutions.

Contribution

It presents a novel, non-linear, self-detuning metasurface that improves MRI performance and safety without additional electronic control components.

Findings

Up to eightfold increase in signal-to-noise ratio in 3T MRI.

No impact on transmit field, ensuring patient safety.

Demonstrated effectiveness through simulations, bench tests, and MRI experiments.

Abstract

Over almost five decades of development and improvement, Magnetic Resonance Imaging (MRI) has become a rich and powerful, non-invasive technique in medical imaging, yet not reaching its physical limits. Technical and physiological restrictions constrain physically feasible developments. A common solution to improve imaging speed and resolution is to use higher field strengths, which also has subtle and potentially harmful implications. However, patient safety is to be considered utterly important at all stages of research and clinical routine. Here we show that dynamic metamaterials are a promising solution to expand the potential of MRI and to overcome some limitations. A thin, smart, non-linear metamaterial is presented that enhances the imaging performance and increases the signal-to-noise ratio in 3T MRI significantly (up to eightfold), whilst the transmit field is not affected due to self-detuning and, thus, patient safety is also assured. This self-detuning works without introducing any additional overhead related to MRI-compatible electronic control components or active (de-)tuning mechanisms. The design paradigm, simulation results, on-bench characterization, and MRI experiments using homogeneous and structural phantoms are described. The suggested single-layer metasurface paves the way for conformal and patient-specific manufacturing, which was not possible before due to typically bulky and rigid metamaterial structures.