In a device and method for monitoring an RF transmission circuit of an MRI device: a first power measurement signal is acquired that indicates a voltage of a first RF signal provided by an RF power amplifier of the RF transmission circuit; two second power measurement signals are received that each indicate a voltage of one second RF signal, the two second RF signals being generated based on the first RF signal by a bridge of the circuit and transmitted via an RF transmit coil; an inverse matrix calculation is performed based on the two second power measurement signals to obtain a voltage calculation value; the voltage calculation value is compared with the first power measurement signal; an operational status of the RF transmission circuit is determined based on a difference between the voltage calculation value and a voltage value of the first power measurement signal.