A Receive-Only Frequency Translation System With Automatic Phase Correction for Simultaneous Multi-Nuclear MRI/MRS.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Receive-only frequency translation allows X-nuclear MRI scanners to perform simultaneous/interleaved multi-nuclear experiments.
• This technique avoids modifying the transmit path but introduces phase incoherence due to differing local oscillator frequencies.
• Retrospective phase correction is currently required, limiting scan flexibility.

Purpose of the Study:

• To present a hardware solution for automatic, real-time phase correction during MRI scans.
• To eliminate the need for retrospective phase correction in multi-nuclear acquisition.
• To enable flexible adjustment of scan parameters for simultaneous/interleaved multi-nuclear experiments.

Main Methods:

• A hardware solution detects and corrects phase changes in the local oscillator (LO) in real time.
• Implementation requires programming spare TTL signals and accessing the scanner system LO.
• Phase correction is applied to the translator LO between transmit and receive.

Main Results:

• The hardware solution effectively corrects phase incoherence introduced by receive-only frequency translation.
• Approximately 3% SNR loss was observed at 31P and 23Na frequencies due to imperfect phase correction.
• The corrected 23Na signal showed an 8-degree phase standard deviation, compared to 6 degrees in the reference.

Conclusions:

• The proposed hardware solution successfully corrects phase incoherence in multi-nuclear MRI.
• Minor imperfections in phase correction exist, with potential for improvement in future upgrades.
• This approach enhances real-time data acquisition and scan parameter flexibility for multi-nuclear MRI.