Three-Line Microstrip Array for Whole-Body MRI System at 7 T

• Main Author: Daniel Hernandez
• Format: Article
• Language: English
• Published: MDPI AG 2021-12-01
• Series: Applied Sciences
• Subjects: Keywords: MRI; three-line microstrip array; RF transmitter; full-body MRI
• Online Access: https://www.mdpi.com/2076-3417/11/1/73

This paper proposes the use of a triple-line microstrip array for transmitting a magnetic field (|B₁⁺|) into the whole body for magnetic resonance applications at ultra-high field strength, such as 7 T. We explored some technologies that can potentially be applied for whole-body 7 T magnetic resonance imaging, as there is ongoing research on this topic. The triple-line microstrip transmission line (t-MTL) array consists of 32 channels. Each channel has a t-MTL, comprising a main conductor line and two adjacent coupled lines. The adjacent lines are not connected directly to the source. This configuration resulted in increased intensity and a centered |B₁⁺|-field. We compared the proposed structure and some reference radiofrequency (RF) transmitters, such as a patch antenna, using a magnet bore as a waveguide and a whole-body birdcage coil. We evaluated the performance of the t-MTL using cylindrical phantoms. We computed the |B₁⁺|-field from each RF transmitter inside a 3D human model containing more than 200 tissues. We compared their uniformity and field intensity and proposed a t-MTL array that yielded better performance. The proposed design also showed a lower specific absorption rate compared with a patch antenna.