Systems and methods for mapping the transmit sensitivity of one or more radio frequency (“RF”) coils for use in magnetic resonance imaging (“MRI”) are described. The transmit RF field (“B1+”) for an RF coil, or an array of RF coils, is mapped using a robust, motion-insensitive technique that implements Bloch-Siegert shifts performed with interleaved positive and negative off-resonance shifts. The motion insensitivity of this technique makes it particularly useful for applications where there is significant motion, such as cardiac imaging, in which previous B1+ mapping techniques are not as accurate or effective.
