摘要:
A method has been conceived for acquisition and accumulation of a magnetic resonance signal in the presence of signal instability due to field or frequency instability. After submitting an element to be examined to a suitable experiment, a sequence of pulses for example, for measurement of an echo signal (Hahn-echo experiment), the detected signal for each τ is broken up into its Cartesian co-ordinates in an IQ plane, the module of the components is calculated and then the calculated modules are added to each other. By operating on the sum of the calculated modules for each τ in order to at least partly remove the introduced noise, interpolation of the calculated points can be carried out so as to determine a course representative of the acquired and accumulated parameter as a function of τ.
摘要:
A low field MRI instrumental system (1) comprises : an electromagnetic Radio Frequency antenna (10) to emit RF pulses for inducing Electron Paramagnetic Resonance ; an electromagnetic Low Frequency antenna (20) for measurements, to emit LF pulses for inducing Nuclear Magnetic Resonance, respectively to receive LF signal produce by NMR; a gradient generator (30), to create a gradient in a static magnetic field generated during measurements; a high field generator (40) to generate a strong pre-polarization magnetic field for magnetic pre-polarization; and, a control/command unit (60). This low field MRI instrumental system (1) is characterized in that it further comprises a low field unit (50) to generate a low static magnetic field whose direction is adjustable along the three directions X, Y and Z of a fixed reference frame associated with the low field MRI instrumental system.
摘要:
A system for NMR assessing a sample or a series of samples in turn which comprises means for applying a static magnetic field in a first direction through the sample, pre-polarising means for first applying a magnetic field in substantially the same direction to the sample, means for applying an alternating excitation magnetic field in a second different direction through the sample, means for sensing energy emitted by the sample in response to the excitation magnetic field, and means arranged to provide an indication of an assessment of the sample based on the energy emitted by the sample in response to the excitation magnetic field.