Systems and methods for utilizing periodic irradiation to enhance sensitivity of magnetic resonance detection

A method for acquiring magnetization data using a magnetic resonance (MR) system , the method including steps comprising:

• applying periodic radiofrequency (RF) irradiation to a spin system in a region of interest in a subject using a frequency swept pulse sequence having frequency and amplitude modulation functions, wherein the frequency swept pulse sequence is configured to generate spin relaxation in the presence of a fictitious field in a second rotating frame of reference based on at least one magnetic field component that arises based on an effective field in a first rotating frame of reference, wherein the second rotating frame of reference is of a higher order than the first rotating frame of reference, and wherein each different rotating frame is associated with an effective field;
• generating off resonance side bands in a frequency domain positioned adjacent a resonant frequency of a first labile spin species in the spin system or a second labile spin species in the spin system by applying the periodic RF irradiation to induce an instantaneous flip of the effective field;
• and
• acquiring magnetization data from the region of interest corresponding to at least one of the off resonance side bands.

A method for acquiring magnetization data using a magnetic resonance (MR) system from a region of interest in a subject having a spin system that includes at least a first labile spin species and a second labile spin species experiencing chemical exchange, the method including steps comprising:

• applying periodic radiofrequency (RF) irradiation to the spin system using a frequency swept pulse sequence having frequency and amplitude modulation functions;
• generating off resonance side bands in a frequency domain positioned adjacent the resonant frequency of the first labile spin species or the second labile spin species by applying the periodic RF irradiation to induce an instantaneous flip of the effective field, and wherein an irradiation period of the RF irradiation is selected to correspond to a chemical shift difference between the first resonant species and the second resonant species;
• and
• acquiring magnetization data corresponding to at least one of the off resonance side bands.