SU‐FF‐I‐63: Evaluation of the Turn Variation of Spiral RF Surface Coils for MR Microscopic Imaging and Spectroscopy

Abstract

Purpose: The purpose of this study was to enhance the technical improvement which can develop the advanced sensitive RF surface coil to investigate the sensitivities of the multi‐spiral surface coils and eventually achieve the high resolution of microscopic MR images and MR spectra. Method and Materials: The simulation of a coil's magnetic field was processed in MATLAB. Biot‐Savart law provides information about the relation between the amplitude and the position. The experiment was processed in the Oxford magnet (1.5T), Copley gradient (25mT/m) coil and Analogic RF amplitude system. The diameter of a coil was fixed at 4cm, and the turn of a coil was increased with a spiral turning method. Results: 1. Simulation of magnetic field. The magnetic field strength was increased close to the wire because of a ring‐shape wire coil. This simulation was performed assuming no obstruction in the current and domain. Thus, the shape and the field distribution of a RF surface coil were able to be visually analyzed. 2. Coils' performance. The ROI with approximately 3cm was identified by a water phantom in 1.5T. The three and five turned spiral coils were developed and their Q‐factor and bandwidth were estimated. Conclusion: The present study showed that the sensitivity of RF surface coil was improved by the increasing the number of a spiral coil's turn, and also the SNR of RF surface coil was dependent upon the number of a spiral coil's turn. However, the sensitivity was not proportional to the number of a spiral RF coil's turn. There is an optimal vale in a spiral RF coil turn and sensitivity. In order to obtain a high sensitivity as varying the spiral RF coil's performance, it is important to find the optimal number of turn. This study provides an efficient approach to designing high‐field RF coils.