New design concept of monopole antenna array for UHF 7T MRI

• Published in: Magnetic resonance in medicine 2014-05, Vol.71 (5), p.1944-1952
• Main Authors: Hong, Suk-Min, Park, Joshua Haekyun, Woo, Myung-Kyun, Kim, Young-Bo, Cho, Zang-Hee
• Format: Article
• Language: English
• Subjects: 7T MRI; Brain - anatomy & histology; Computer-Aided Design; dipole antenna; Equipment Design; Equipment Failure Analysis - instrumentation; Humans; Image Enhancement - instrumentation; Magnetics - instrumentation; monopole antenna; monopole antenna array; Reproducibility of Results; Sensitivity and Specificity; Transducers
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.24844

Purpose We have developed and evaluated a monopole antenna array that can increase sensitivity at the center of the brain for 7T MRI applications. Methods We have developed a monopole antenna array that has half the length of a conventional dipole antenna with eight channels for brain imaging with a 7T MRI. The eight‐channel monopole antenna array and conventional eight‐channel transceiver surface coil array were evaluated and compared in terms of transmit properties, specific absorption ratio (SAR), and sensitivity. The sensitivity maps were generated by dividing the SNR map by the flip angle distribution. Results A single surface coil provides asymmetric sensitivity resulting in reduced sensitivity at the center of the brain. In contrast, a single monopole antenna provides higher sensitivity at the center of the brain. Moreover, the monopole antenna array provides uniform sensitivity over the entire brain, and the sensitivity gain was 1.5 times higher at the center of the brain compared with the surface coil array. Conclusion The monopole antenna array is a promising candidate for MRI applications, especially for brain imaging in a 7T MRI because it provides increased sensitivity at the center of the brain. Magn Reson Med 71:1944–1952, 2014. © 2013 Wiley Periodicals, Inc.