Techniques for determining a nuclear magnetic resonance relaxation time and/or a nuclear magnetic resonance spectrum of a probe

A method of determining a nuclear magnetic resonance relaxation time of a probe and/or a nuclear magnetic resonance spectrum of a probe, wherein the probe comprises first nuclei with a first gyromagnetic ratio and second nuclei with a second gyromagnetic ratio, and the first gyromagnetic ratio is larger than the second gyromagnetic ratio, the method comprising:

• a first step of polarizing the first nuclei and the second nuclei by applying a longitudinal static magnetic field B0 to the probe;
• a second step of exchanging the polarizations of the first nuclei and the second nuclei by irradiating at least one swap sequence of transverse magnetic field pulses;
• a third step of transversely magnetizing the second nuclei by irradiating at least one excitation pulse and measuring the resulting magnetization signal;
• and
• a fourth step of determining the nuclear magnetic resonance relaxation time and/or the nuclear magnetic resonance spectrum based on the measured magnetization signal;
• wherein the irradiating of the at least one swap sequence of transverse magnetic field pulses, the irradiating of the first sequence of transverse magnetic field pulses and/or the irradiating of the second sequence of transverse magnetic field pulses in the second step comprises:
• irradiating a first transverse magnetic field pulse, wherein the first transverse magnetic field pulse is a (πx/2)-pulse;
• irradiating a second transverse magnetic field pulse with a predetermined time delay tD after irradiating the first transverse magnetic field pulse, wherein the second transverse magnetic field pulse is a πx-pulse;
• irradiating a third transverse magnetic field pulse with the predetermined time delay tD after irradiating the second transverse magnetic field pulse, wherein the third transverse magnetic field pulse is a πx-pulse;
• irradiating a fourth transverse magnetic field pulse with no time delay and immediately after irradiating the third transverse magnetic field pulse, wherein the fourth transverse magnetic field pulse is a (π−x/2)-pulse;
• irradiating a fifth transverse magnetic field pulse with no time delay and immediately after irradiating the fourth transverse magnetic field pulse, wherein the fifth transverse magnetic field pulse is a (πy/2)-pulse;
• irradiating a sixth transverse magnetic field pulse with the predetermined time delay tD after irradiating the fifth transverse magnetic field pulse, wherein the sixth transverse magnetic field pulse is a πx-pulse;
• and
• irradiating a seventh transverse magnetic field pulse with the predetermined time delay tD after irradiating the sixth transverse magnetic field pulse, wherein the seventh transverse magnetic field pulse is a (π−y/2)-pulse.

A method of determining a nuclear magnetic resonance relaxation time of a probe and/or a nuclear magnetic resonance spectrum of a probe, wherein the probe comprises first nuclei with a first gyromagnetic ratio and second nuclei with a second gyromagnetic ratio, and the first gyromagnetic ratio is larger than the second gyromagnetic ratio, the method comprising:

• a first step of polarizing the first nuclei and the second nuclei by applying a longitudinal static magnetic field B0 to the probe;
• a second step of exchanging the polarizations of the first nuclei and the second nuclei by irradiating at least one swap sequence of transverse magnetic field pulses;
• a third step of transversely magnetizing the second nuclei by irradiating at least one excitation pulse and measuring the resulting magnetization signal;
• and
• a fourth step of determining the nuclear magnetic resonance relaxation time and/or the nuclear magnetic resonance spectrum based on the measured magnetization signal;
• wherein the probe also comprises third nuclei with a third gyromagnetic ratio, and the exchanging of the polarization of the first nuclei and the second nuclei by irradiating at least one swap sequence of transverse magnetic field pulses in the second step comprises:
• exchanging of the polarization of the first nuclei and the third nuclei by irradiating a first swap sequence of transverse magnetic field pulses;
• exchanging of the polarization of the third nuclei and the second nuclei by irradiating a second swap sequence of transverse magnetic field pulses;
• and
• exchanging of the polarization of the first nuclei and the third nuclei by irradiating a third swap sequence of transverse magnetic field pulses.

An apparatus configured to determine a nuclear magnetic resonance relaxation time of a probe and/or a nuclear magnetic resonance spectrum of a probe, wherein the probe comprises first nuclei with a first gyromagnetic ratio and second nuclei with a second gyromagnetic ratio, and the first gyromagnetic ratio is larger than the second gyromagnetic ratio, wherein the apparatus comprises:

• at least one static magnetic field generating unit configured to polarize the first nuclei and the second nuclei by applying a longitudinal static magnetic field B0 to the probe;
• at least one electromagnetic pulse generating unit configured to exchange the polarizations of the first nuclei and the second nuclei by irradiating at least one swap sequence of transverse magnetic field pulses, and to transversely magnetize the second nuclei by irradiating at least one excitation pulse of transverse magnetic field pulses;
• at least one signal receiving unit configured to measure a magnetization signal resulting from the at least one excitation pulse;
• and
• at least one electronic control and evaluation unit configured to determine the nuclear magnetic resonance relaxation time and/or the nuclear magnetic resonance spectrum based on the measured magnetization signal, wherein a temporal length of the at least one swap sequence is substantially identical to an inverse of the longitudinal spin-spin interaction strength between the first nuclei and the second nuclei.