MAGNETIC RESONANCE IMAGING AND SPECTROSCOPY OF LOW CONCENTRATION SOLUTES WITH EXCHANGEABLE PROTONS USING LABEL TRANSFER MODULES: FREQUENCY TRANSFER, INVERSION TRANSFER, AND DEPHASING TRANSFER
An embodiment of the current invention provides a method for magnetic resonance (MR) imaging or spectroscopy, comprising: (a) selectively exciting exchangeable solute protons or protons of exchangeable solute-based water molecules within a frequency range in a subject using at least one frequency-selective radio frequency (RF) pulse, wherein the frequency range encompasses characteristic resonance frequencies of the exchangeable solute protons or protons of exchangeable solute-based water molecules, wherein the frequency range is substantially non-overlapping with a characteristic resonance frequency of bulk water protons in the subject, wherein the at least one frequency selective RF pulse performs a substantially minimal excitation on the bulk water protons, and wherein the at least one frequency-selective RF pulse, sometimes in combination with a time period that separates the at least one frequency-selective RF pulse, magnetically labels the exchangeable solute protons or the exchangeable solute-based water molecules (b) allowing a portion of the magnetically labeled exchangeable solute protons to exchange with the bulk water protons or allowing the magnetically labeled exchangeable solute-based water molecules to exchange with bulk water molecules
