Resonance Frequency Detection System for MRI RF Coils

Magnetic resonance imaging (MRI) is an important tool for medical diagnostics. Stretchable and flexible RF coils for MRI offer improved adaptability to patient anatomy and the potential for enhanced image quality. These coils are susceptible to resonance frequency shifts due to variations in inductance when stretched, compressed, or bent, which can severely impact the signal-to-noise ratio and overall image quality. Addressing this challenge, we present a system to actively detect the resonance frequency of the coil. The system employs a superheterodyne receiver architecture and a broadband resistive return-loss bridge that does not rely on ferromagnetic components. Our system is capable of operating within the MRI bore at Larmor frequencies of up to 600 MHz with a resonance frequency measurement accuracy of 99.92% at 3 T. This system offers a potential solution for integrating automatic tuning and matching circuits in future MRI applications, ensuring reliable performance across various coil configurations and field strengths.