Another alternate integrated circuit approach to modulation of radiofrequency transmission signals in magnetic resonance imaging

Abstract

Parallel radiofrequency transmission has garnered much attention for its wide range of benefits in magnetic resonance imaging (MRI), including reduced power deposition and radiofrequency excitation with improved spatial uniformity. However, few pTx systems are commercially available and most are expensive. This manuscript introduces another alternative parallel transmit architecture at 3 T based on field-programmable gate array technology, and explores the utility of a low cost, integrated circuit approach to signal modulation that is easily scaled to high channel counts. The technical and engineering specifications of a complete 4-channel signal modulation module are presented in detail, including radiofrequency characterization and MRI results. The experimental results are additionally compared to a commercially available 4-channel modulation system. The findings indicate that the proposed device is easy to use, provides fine control of phase and amplitude on existing MRI systems, and can be fabricated for approximately 30 USD per channel. Initial estimates suggest that the complete 4-channel modulation system (including the required software licenses and multi-function reconfigurable input/output devices) can be implemented for approximately 10 000 USD.