Detecting spin perturbations using magnetic resonance imaging

A computer program product, embodied on a non-transitory computer-readable medium, operable to cause a data processing apparatus to perform operations comprising:

• generating signals for applying to a sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence;
• and
• processing a magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of a magnetic field perturbation in the sample.

A magnetic resonance imaging (MRI) system comprising:

• a radio frequency (rf) system configured to apply to a sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses and to detect a magnetic resonance signal from the sample in response to the periodic pulse sequence, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the sample, a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence;
• and
• a data processing apparatus configured to process the magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of a magnetic field perturbation in the sample.

A method comprising:

• applying a periodic pulse sequence to a nervous system, the pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the nervous system, multiple different steady states of magnetization in the nervous system during each period of the pulse sequence;
• and
• processing a magnetic resonance signal acquired from the nervous system when under application of the periodic pulse sequence to obtain characteristics of neuronal activity associated with the magnetic field perturbation.