Di Qian1,2, AbdELMonem M. EL-Sharkawy1, Paul A. Bottomley1,2
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, School of Medicine, Baltimore, MD, USA; 2Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
The interventional loopless antenna has low tip sensitivity, which is exacerbated by uniform insulation. It is shown that the antennas current sensitivity can be redistributed distally by tapering the insulation. Electromagnetic (EM) method-of-moment analysis, experiments in phantoms and biological specimens at 3T, demonstrate that tapering can produce ~4-fold gains in the signal-to-noise ratio 1cm from the tip. Insulation tapering enhances the tip visibility for interventional MRI (iMRI) using loopless antennae without compromising the antennas tiny cross-sectional profile. Numerical EM analysis is a valuable design tool for improving the performance characteristics.