The invention provides for a metal detector (100, 300) with at least a first coil (102) for generating a first magnetic field (108) along a first direction (119). The first coil is a split coil with a first (104) and a second (106) portion (104). A coil power supply (110) separately supplying time varying electrical power to the coil portions. At least one electrical sensor (116, 118) measures electrical data (136) descriptive of the electrical power supplied to at least the first coil portion and the second coil portion. The coils are controlled such as to move a field-free region in a predetermined pattern within a measurement zone. If metal is detected, the pattern is modified for refining localisation of the metallic object.

A protocol to determine chemical shift-specific T.sub.1 constants in inhomogeneous fields. Based on intermolecular double-quantum coherences and spatial encoding techniques, the method can resolve overlapped peaks in inhomogeneous fields using the conventional method. With inversion recovery involved, the amplitude of peaks will be modulated by the time of inversion recovery. After fitting the amplitude curves, the corresponding longitudinal relaxation time can be achieved. With the measured T.sub.1 values in inhomogeneous fields, we can have insights into the chemical exchange rates, signal optimization and data quantitation.

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.

The invention relates to compounds known as optorelaxers, for example, spin crossover (SCO) complexes that exhibit light-induced excited state spin trapping (LIESST) effects with transient unpaired electron spins, which are created (or destroyed) by varying the level and/or wavelength of light to which the complexes are exposed. Light conditions are used to switch the optorelaxers between transient paramagnetic and diamagnetic states to provide real-time control of T.sub.1 relaxation in nuclear magnetic resonance (NMR) spectroscopy methods. The optorelaxers and methods of the invention provide increased detection sensitivity of NMR spectroscopy, with increased structural information content, while maintaining resolution for a wide variety of different NMR-active nuclei.

Systems and methods are disclosed for a pulse sequence that reduces disorder and/or interaction effects in spin systems. A protocol can be used to design a pulse sequence that includes altering the frame orientation of the spin system with each electromagnetic pulse in the pulse sequence. The frame orientations during the sequence can conform to certain conditions. The number positive rotations along each axis can be the same as the number negative rotations along the respective axis. The number of rotations along one axis should be the same as the number of rotations along the other axes.

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 of acquiring an image at a magnetic resonance imaging (MRI) system is provided. Accordingly, an analog signal based on a pulse sequence and a first gain is obtained. The analog signal is converted into a digitized signal. A potential quantization error is detected in the digitized signal based on a boundary. When the detection is affirmative, a replacement analog signal based on the pulse sequence is received. At least one portion of the replacement analog signal can be based on an adjusted gain. The adjusted gain is a factor of the first gain. The replacement analog signal is digitized into a replacement digitized signal. At least one portion of the replacement digitized signal corresponding to the at least one portion of the replacement analog signal is adjusted based on a reversal of the factor.

The invention features a novel non-invasive approach for imaging, detecting and/or sensing metal ions with improved sensitivity and specificity in a biological sample or tissue. In certain embodiments, the invention provides a MR contrast-based approach for imaging, detecting and/or sensing metal ions in the biological sample/tissue containing various background ions by using .sup.19F-based chemical exchange saturation transfer (CEST) technique.

Methods of and systems for making a hyperpolarized fluid are provided, which include exposing a fluid and parahydrogen to a catalyst. The hyperpolarized fluid can be introduced to a subject. The hyperpolarized fluid can be included in methods of imaging a subject. Also provided are methods that use the hyperpolarized fluids for detecting protein ligand interactions and for enhancing the NMR signals of biopolymers having chemically exchangeable protons.

The invention relates to a method for generating a nuclear magnetic resonance spectrum (4) of nuclear spin moments (6) of a sample (8), comprising a static magnetic field (B) permeating the sample (8), and a detection spin moment (16) with a detection region (18) surrounding the latter, said detection region extending at least partly into the sample (8), and also an antenna element (22) for radiating in frequency pulses (F) for influencing the nuclear spin moments (6) and radio-frequency pulses (H) for influencing the detection spin moment (16), wherein a polarization step (42) involves polarizing at least one portion of the nuclear spin moments (6) along the magnetic field (B) to form a longitudinal magnetization (M.sub.z), wherein a transfer step (44) involves converting the longitudinal magnetization (M.sub.z) into a transverse magnetization (M.sub.xy) by radiating in a frequency pulse (F) with a 90 flip angle, wherein a detection step (46) involves radiating in a sequence (S) of radio-frequency pulses (H) onto the detection spin moment (16) and subsequently detecting a signal (32) of the transverse magnetization (M.sub.xy) present in the detection region (18) and storing said signal as detection result (48) in a list (50), wherein the detection step is carried out a number of times repeatedly in succession, wherein the polarization step (42) and the transfer step (44) and also the detection steps (46) are carried out repeatedly until a predefined number of repetitions (N) is reached, wherein a new list (50) with detection results (48) is generated with each repetition (N), and wherein an evaluation step (54) involves jointly evaluating the detection results (48) of the lists (50) across all repetitions (N).