A method is presented for controlling a spin system in an external magnetic field. The method includes sending a first pulse to a resonator over a first period. The resonator generates a magnetic field in response to receiving the first pulse. Moreover, the resonator applies the magnetic field to the spin system and the first pulse maintains the magnetic field in a transient state during the first period. The method also includes sending a second pulse to the resonator over a second period immediately following the first period. The resonator alters a magnitude of the magnetic field to zero in response to receiving the second pulse. Other methods are presented for controlling a spin system in an external magnetic field, including systems for controlling a spin system in an external field.

According to one embodiment, a MRI apparatus includes an RF coil apparatus receiving MR signals by coil elements corresponding to channels, modulating the MR signals to have different frequencies for each of the channels, and outputting an analog multiplexed signal in which the MR signals with different frequencies are composited over the channels, and a receiver including ADC circuitry converting the analog multiplexed signal to a digital multiplexed signal, and predetermined number of separation channels separating the digital multiplexed signal, based on the number of the channels relating to composition of the MR signals with the different frequencies. The receiver stops a separation process of the digital multiplexed signal for separation channels not used in the separation process among the predetermined number of separation channels.

This invention provides a NMR multi-dimensional method for measuring coupling constants within several coupling networks. At first, a 90 hard pulse was performed to flip the magnetization from the Z axis to the XY plane. After t.sub.1/2, a selective 180 pulse is implemented with a simultaneous Z-direction gradient, thus reversing different protons at different slices. Then the PSYCHE element is implemented. After another t.sub.1/2, the gradient G.sub.1 and G.sub.p are implemented. At last, the EPSI readout is used to simultaneously record both the chemical-shift and the spatial information. As a result, from different specific slices, we can extract the scalar couplings between the proton reversed at this slice and other protons. These couplings lead to splittings in the indirect dimension, from which relevant coupling constants can be measured.

An apparatus and a method for spatial encoding in magnetic resonance tomography using a radio frequency signal are provided. A first set of parameters from a first frequency and from a first amplitude, and from a second frequency and a second amplitude is determined by the magnetic resonance tomograph, and corresponding signals are generated by a radio frequency device and transmitted by an antenna apparatus. A first gradient above the Larmor frequency of the nuclear spins is generated by the Bloch-Siegert effect. The same thing ensues with a second set of parameters that differs from the first set of parameters at least in one frequency or amplitude and therefore generates a second, different gradient.

A method for correcting a B0 inhomogeneity in a magnetic resonance scan with a magnetic resonance tomograph is provided. The magnetic resonance tomograph includes a controller, a radio frequency unit, and a transmitting antenna. In the method, the controller determines a transmission signal that is suitable for correcting an effect of an inhomogeneity of a static B0 magnetic field in an examination volume by the Bloch-Siegert effect. The transmission signal is emitted into the examination volume.

Described here are systems and methods for designing and implementing spatially selective, multidimensional adiabatic radio frequency (RF) pulses for use in magnetic resonance imaging (MRI). Spatially selective inversion can be achieved adiabatically in both two-dimensional (2D) and three-dimensional (3D) regions-of-interest. The multidimensional adiabatic pulses are generally designed using sub-pulses that are adiabatically driven using a parent adiabatic pulse.

A method for carrying out two-field nuclear magnetic resonance (=2FNMR) measurements involves preparing a sample (9a) in a first working volume (5) of a highly homogeneous magnetic field with a first field strength; transferring the sample (9a) to a second working volume (7) with a magnetic field having lower homogeneity and having a second field strength, wherein the first field strength is at least 2 Tesla larger than the second field strength; manipulating the sample (9a) at the second working volume (7) by applying a sequence of radio-frequency (=RF) and/or field gradient pulses; transferring the sample (9a) back to the first working volume (5); and detecting an NMR signal of the sample (9a) in the first working volume (5). The method allows for NMR experiments with which more and/or improved quality information about an investigated sample can be obtained.

In an embodiment of the invention inductive coupling of an idler coil to a parent coil is used to provide a double resonance circuit without the disadvantages of capacitive coupling to the parent coil. In an embodiment of the invention, an inductive coupling coil can be used to achieve a double-tuned circuit. In an embodiment of the invention, a circuit uses inductive coupling to achieve a double resonance circuit for .sup.1H, .sup.19F, and .sup.13C experiments where one of the three nuclei are observed and the other two are decoupled. In an embodiment of the invention a pivot or a shunt can be used to couple and decouple the idler coil and the parent coil.

Techniques for crushing unwanted coherence pathways during magnetic resonance spectral (MRS) measurements include receiving first data that indicates a sequence of RF pulses with one or more target coherence pathways of spin states for a subject that has at least N1 coupled spin states of interest. A negative, non-integer amplitude is determined for at least one intervening crusher pulse emitted from at least one spatial gradient magnetic coil. The at least one intervening crusher pulse has a duration less than a time between successive pulses of the sequence of RF pulses; and, the intervening crusher pulse de-phases unwanted coherence pathways. A MRS device is operated using the intervening crusher pulse and the sequence of RF pulses.

A system and method for detecting a nucleus of interest in a chemical using a nuclear quadrupole resonance transition. An excitation pulse is used to excite one or more nuclei of interest, if they present in a sample, to an excited state, the energy of which depends on the magnetic field in the sample. The magnetic field in the sample is modulated, after the end of the excitation pulse, while the nuclei of interest decay from the excited state, so that the radiation they emit is frequency modulated. The frequency modulation is detected in the emitted radiation. In some embodiments a DC magnetic field is applied to the sample, during the application of the excitation pulse, to tune the frequency of the transition being excited.