Magnetic resonance technologies based on reverse polarization for image-guided interventions

Abstract

In this PhD dissertation, we presented four magnetic resonance (MR) technologies established upon reverse polarization for image guided interventions. The first three studies are based on tracking interventional devices, such as catheters, biopsy needles, and guidewires. The interventional devices cannot be seen using MRI without markers, coils, or extra devices. Our studies utilize different imaging modalities in order to obtain positional information of the interventional devices. The last study is a novel inductively coupled radio frequency birdcage coil design, which is a miniaturized version of a widely used volume coil. The new design can be used for prostate biopsy or imaging intestines. The reverse polarization is a mode of magnetic field that is not sensitive to anatomy signal. Therefore, it had been useless until the introduction of the reverse polarization concept. Using a linearly polarized inductively coupled radio frequency (ICRF) coil enables the reverse polarization mode, because a linearly polarized signal consists of both forward and reverse polarization signals. As a result, building the ICRF coil to interventional devices paves the way of using this method in interventional MRI. Performances of developed technologies were tested in phantom, animal, and volunteer studies. We believe that the studies explained in this dissertation contribute to obtaining better imaging systems.