An electron paramagnetic resonance imaging system that includes means for continuously irradiating a sample with RF irradiation; means for imposing on the sample a sinusoidally varying magnetic field along with rotating gradients for spatial encoding; means for directly detecting signal data from the sample, without using field modulation, while irradiating the sample with RF radiation continuously, the means for directly detecting having means for sweeping the sinusoidally varying magnetic field; and means for processing the signal data, using means including a digital signal processor.