Design of microstrip‐based surface coils for low‐field small‐bore MR applications

Abstract

Microstrip transmission line concept, which has been used to construct microwave integrated circuits or high frequency (!300 MHz) antennas, is introduced to surface receive coils for use in a small volume coil at 1T and the feasibility of the microstrip-based coils is investigated. Both single-turn and two-turn microstrip receive coils are fabricated. The size of the square shaped coil loop is 2.5 3 2.5 cm 2 . A lengthening inductor (toroid) is used to replace a long coaxial cable (5217 cm) needed for low-field small-bore MR applications. The lengthening inductor, matching, and tuning capacitors are located outside the magnet. One pulse and a gradient reversed form of FISP sequences are used to acquire NMR signals and MR images of gel phantoms, respectively. MR images acquired by the two-turn coil have higher SNR and more uniform signal intensity than those obtained by the single-turn coil and the volume coil. A novel, easy, and efficient method to design small microstrip-based RF surface receive coils is developed and tested for low-field small-bore MR applications.