Magnetization transfer and off-resonance protocols in NMR
A method includes acquiring a signal intensity from a spin system after applying the radio frequency preparation pulses prior to the imaging readout or spectroscopic localization, and acquiring signal intensity starting with magnetization initially rotated to a certain angle by applying an initial pulse before the preparation scheme, and processing the data to generate an image or spectra corresponding to the spin system. The imaging or spectroscopy sequence is configured to provide data based on magnetization transfer or an off-resonance effect.
1. A magnetic resonance system comprising:
a driver unit configured to apply a perturbation to a spin system; and
a processor coupled to the driver unit, the processor programmed to generate an initial pulse followed by a data acquisition train, wherein the data acquisition train provides data based on magnetization transfer or off-resonance irradiation, and
wherein the processor is programmed to generate an image or spectra corresponding to the spin system in which magnetization is initially aligned with a positive z-axis of the spin system and programmed to generate an image or spectra corresponding to the spin system in which magnetization is initially aligned with a negative z-axis of the spin system.
2. The system of claim 1 wherein the driver unit is configured to apply the initial pulse, and the initial pulse is configured to rotate magnetization to a preset angle.
3. The system of claim 1 wherein the processor is programmed to cause the driver unit to apply off-resonance irradiation.
4. The system of claim 1 wherein the processor is programmed to cause the driver unit to apply the data acquisition train.
5. The system of claim 1 wherein the processor is programmed to generate a ratio corresponding to magnetization transfer.
6. A magnetic resonance method comprising:
programming a processor to perform as follows:
applying an imaging sequence or spectroscopy sequence when initial magnetization of a spin system is aligned with a positive z-axis, the sequence configured to provide data based on an off-resonance preparation;
applying an initial, on-resonance pulse to the spin system, the initial pulse configured to rotate magnetization to a negative z-axis of the spin system;
applying an imaging sequence or spectroscopy sequence following the initial pulse, the sequence configured to provide data based on an off-resonance preparation; and
processing the data to generate an image or spectra corresponding to the region of interest.
7. The method of claim 6 wherein applying the imaging sequence includes applying a sequence configured for at least one of magnetization transfer (MT), chemical exchange saturation transfer (CEST), spin-lock T 1ρ (SL-T 1ρ ), or relaxation along a fictitious field (RAFF).
8. The method of claim 6 wherein applying the initial pulse includes applying a radio frequency pulse which aligns magnetization substantially on the negative z-axis.
9. The method of claim 6 wherein applying the initial pulse includes applying a pulse prior to imaging readout or spectroscopic localization.
10. The method of claim 6 wherein applying the imaging sequence or spectroscopy sequence includes applying an off-resonance continuous wave or pulsed irradiation.
11. The method of claim 6 wherein applying the imaging sequence or spectroscopy sequence includes applying a pulse train configured to induce formation of a steady state of magnetization.
12. The method of claim 6 further including generating a ratio corresponding to magnetization transfer.
13. The method of claim 6 wherein processing the data includes quantifying an intrinsic relaxation parameter.