Intraluminal MRI probe using small size variable capacitor

An intraluminal magnetic resonance imaging (MRI) probe holds promise to achieve a higher resolution image of a small pathological lesion than conventional external probes. Such an intraluminal probe requires precise resonant frequency tuning to 63.865 MHz and impedance matching to 50 Ω, if used for instance in a 1.5-T scanner. Tuning and matching have to be performed after inserted into the subject body as electric permittivity varies according to the tissue location. Thus, in this study, a novel intraluminal MRI probe which can be tuned and matched remotely by voltage-controlled, MOSFET-type variable capacitors was developed and fabricated. The imaging capability and signal-to-noise ratio (SNR) was evaluated in an agar phantom.