Magnetic resonance imaging apparatus and its anomaly detection method

摘要

PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging apparatus effectively detecting miswiring and oscillation of an output current of a gradient magnetic field coil.SOLUTION: A magnetic resonance imaging apparatus comprises: an inverter circuit 51x that is connected to a direct-current voltage source; a current sensor 44x that detects a current to be supplied to an Xch coil 22x as an output of the inverter circuit 51x; a switching control circuit 52x that calculates a switching waveform on the basis of an input signal and an error signal output from the current sensor 44x, and performs pulse width modulation control of the inverter circuit 51x on the basis of the switching waveform; an Xch comparator 46x that obtains a difference between a predicted switching waveform and the actual switching waveform which is calculated by the switching control circuit 52x on the basis of the switching waveform whose duty factor is 50%, and generates an output pulse waveform; and a sequencer 30 that detects abnormality when an integral value of the output pulse waveform in a time width corresponding to a natural number multiple of a pulse interval of the predicted switching waveform is not equal to 0.