Systems and Methods for Magnetic Field-Dependent Relaxometry Using Magnetic Resonance Imaging

A magnetic resonance imaging (MRI) system, comprising:

• magnet coils for generating a magnetic field, wherein the magnet coils are composed of a superconducting material;
• a power supply;
• a superconducting switch selectively connecting the magnet coils to the power supply and having an open state and a closed state, wherein when in the closed state the superconducting switch connects the magnet coils and the power supply in a connected circuit;
• a controller programmed to ramp the magnetic field generated by the magnet coils between a plurality of different magnetic field strengths by adjusting the current generated by the power supply when the superconducting switch is in its closed position;
• a mechanical cryocooler in thermal contact with the magnet coils and operable to reduce and maintain a temperature of the magnet coils below a transition temperature of the superconducting material while the magnetic field generated by the magnet coils is being ramped between the plurality of different magnetic field strengths;
• a radio frequency (RF) system comprising an RF coil operable to provide RF excitation and a receiver operable to detect magnetic resonance signals;
• and
• a processor in communication with the controller and the RF system, wherein the processor is configured to:
• control the controller to ramp the magnetic field though the plurality of different magnetic field strengths;
• control the RF system to provide RF excitation with the RF coil while the magnetic field is ramped to each of the plurality of different magnetic field strengths;
• and
• control the RF system to receive magnetic resonance signals at each of the plurality of different magnetic field strengths via the receiver.