Development of an Add-on 23 Na-MRI Radiofrequency Platform for a 1 H-MRI System Using a Crossband Repeater: Proof-of-concept.

Na-MRI provides information on Na content, and its application in the medical field has been highly anticipated. However, for existing clinical H-MRI systems, its implementation requires an additional broadband RF transmitter, dedicated transceivers, and RF coils for Na imaging. However, a standard medical MRI system cannot often be modified to perform Na imaging. We have developed an add-on crossband RF repeater system that enables Na-MRI simply by inserting it into the magnet bore of an existing H MRI. The three axis gradient fields controlled by the H-MRI system were directly used for Na imaging without any deformation. A crossband repeater is a common technique used for amateur radio. This concept was proven by a saline solution phantom and in vivo mouse experiments. This add-on RF platform is applicable to medical H MRI systems and can enhance the application of Na-MRI in clinical usage.