Making RF coils MR-invisible by additive manufacturing using magnetically filled polymer

Motivation: In MRI of tissues with short T2, materials of RF coils may be detected and can cause background artefacts. Current solutions to this problem either compromise sequence performance or impose restrictions on coil design. Goal(s): Making RF coils MR-invisible. Approach: The material used for constructing the coil housing is filled with ferrimagnetic material, leading to effective signal spoiling. Coil formers are created by additive manufacturing using custom filaments made from magnetite-filled polymer. Results: Unwanted signals from the RF coil are eliminated by using coil formers made from magnetically filled polymer. Hence, background-free short-T2 imaging is enabled. Impact: RF coils made MR-invisible by using magnetically-filled materials simplify coil design and manufacturing, and improve the performance of MRI of tissues with short T2, such as bone, tendon, lung, or myelin.