Magneto-Inductive Catheter Receiver for Magnetic Resonance Imaging

• Published in: IEEE transactions on biomedical engineering Vol. 60; no. 9; pp. 2421 - 2431
• Main Authors: Syms, Richard R. A., Young, Ian R., Ahmad, Munir M., Taylor-Robinson, Simon D., Rea, Marc
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-09-2013
• Subjects: Catheters; Detectors; Duodenoscopy - instrumentation; Equipment Design; Inductors; Magnetic resonance imaging; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; magneto-inductive waveguide; Materials; metamaterial; Microcoil; Phantoms, Imaging; Radio Waves; Receivers; Resonant frequency
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2013.2258020

A catheter-based RF receiver for internal magnetic resonance imaging is demonstrated. The device consists of a double-sided thin-film circuit, wrapped around a hollow catheter and sealed in place with heat-shrink tubing. Signals are detected using a resonant LC circuit at the catheter tip and transmitted along the catheter using an array of coupled LC circuits arranged as a magneto-inductive waveguide, a form of low frequency metamaterial. Coupling to a conventional RF system is accomplished using a demountable inductive transducer. Protection against external B 1 and E fields is obtained by using figure-of-eight elements with an electrical length shorter than that of an immersed dipole. The system is primarily designed for biliary imaging, can pass the biopsy channel of a side-opening duodenoscope, and is guidewire-compatible, potentially allowing clinicians to implement MR image guided procedures without changing their standard practice. Decoupling against B 1 and E fields is verified, and in vitro 1 H magnetic resonance imaging with submillimeter resolution is demonstrated at 1.5 T using phantoms.