An active TX/RX NMR probe for real-time monitoring of MRI field imperfections

In this paper, we present a PCB-based active miniaturized MR field probe for real-time monitoring of the magnetization´s phase evolution during magnetic resonance (MR) experiments. The data obtained with the presented sensor can be used to correct gradient field imperfections which uncorrected result in significant distortions in the reconstructed MR images. The presented active field probe consists of a susceptibility matched solenoidal MR coil and a complete homodyne transceiver. Thanks to the local generation of the radio frequency signal required for the excitation of the spin ensemble and the downconversion of the recorded MR signal to low frequencies, the proposed architecture significantly reduces the crosstalk between the probe head and the MR imaging object compared to existing designs. MR measurements performed in an ultra high field 9.4 T full-body scanner prove the compatibility of the presented sensor with commercial MR imaging systems and demonstrate its excellent MR phase tracking performance.