Multi-channel transmit/receive radio frequency (RF) system which individually monitors currents in each of a plurality of antenna elements of a magnetic resonance (MR) imaging coil system

A multi-channel transmit/receive radio frequency (RF) system for a magnetic resonance examination system and comprising:

• an RF antenna array including a plurality of N antenna elements;
• a modulator configured to supply electrical waves to each of the antenna elements under control of a control processor at a predetermined input amplitude and phase and frequency band;
• a plurality of directional couplers, each of the directional couplers circuited between a respective one of the plurality of antenna elements and the modulator;
• a detector configured to measure forward electrical wave amplitude(s) and reflected electrical wave amplitude(s) at each of the directional couplers, in each of a tuned electrical condition of the corresponding antenna elements and a detuned electrical condition of the corresponding antenna elements, in the tuned condition the antenna elements are tuned to be resonant in the frequency band and in the detuned electrical condition the antenna elements are detuned to be non-resonant in the frequency band;
• a memory configured to store a matrix M where
• M
• =
• (
• α
• 11
• 0
• 0
• β
• 11
• 0
• 0
• 0
• …
• 0
• 0
• …
• 0
• 0
• 0
• α
• NN
• 0
• 0
• β
• NN
• )
• where matrix elements α are calculated during pre-imaging calibration for forward electrical waves, and matrix elements β are calculated during pre-imaging calibration for reflected electrical waves;
• and
• an arithmetic processor configured to compute the individual antenna element currents I1, . . . N on the basis of the measured forward electrical wave amplitudes a, . . . aN, and reflected electrical wave amplitudes b1, . . . , bN, where
• I
• =
• M
• ⁡
• (
• a
• 1
• …
• a
• N
• b
• 1
• …
• b
• N
• )
• where I is a vector containing the N individual antenna elements.