Patent ID: 8938281
Filing Date: 2015-01-20
Classification: G01R

Abstract:
1. A magnetic resonance imaging apparatus comprising an array of two or more RF antennas for transmitting RF pulses to and receiving received MR signals from a body of a patient positioned in an examination volume, the two or more RF antennas having spatial transmit sensitivity profiles and receive sensitivity profiles, wherein the magnetic resonance imaging apparatus is configured to: control a temporal succession, phases and amplitudes of RF feeding of each individual RF antenna, the phases and amplitudes being determined from the spatial transmit sensitivity profiles of the two or more RF antennas; reconstruct a MR image from a combination of the received MR signals received via the individual RF antennas and from the spatial receive sensitivity profiles of the two or more RF antennas; subject the body to a single absolute field mapping sequence comprising RF pulses that are generated by using a first set of phases and amplitudes of the RF feeding of the two or more RF antennas; acquire acquired MR signals, from which a single absolute map of a spatial distribution of the RF field transmitted during the single absolute field mapping sequence is derived; subject the body to at least one relative field mapping sequence comprising RF pulses that are generated by using a second set of phases and amplitudes of the RF feeding of the two or more RF antennas; acquire acquired MR signals, from which a relative map of the spatial distribution of the RF field transmitted during the relative field mapping sequence is derived for each individual RF antenna of the two or more RF antennas resulting in a plurality of relative maps, wherein the relative map is a localized representation of an MR image at a respective RF antenna location; determine the spatial transmit sensitivity profiles of the two or more RF antennas from a combination of the single absolute map and from the plurality of relative maps; and determine the spatial receive sensitivity profiles of the two or more RF antennas from the spatial transmit sensitivity profiles of the two or more RF antennas.