The
reflected power of transmit RF coils is influenced by the position of the
diaphragm. In this work the diaphragm position is measured in real-time for
every RF pulse with a hybrid approach. The set of reflection coefficients are
transformed into a diaphragm position using a series of MR diaphragm navigators
at the start of the pulse sequence in a learning cycle. We demonstrate high
quality respiratory gated data based on gating via this mechanism using
standard SAR monitoring hardware with a real-time lag of 23ms and temporal
resolution of 4.5ms.
