Multicoil NMR data acquisition and processing methods
AssigneeVista Clara Inc.
InventorDavid Walsh
Life of this patent
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Abstract
A multicoil NMR data acquisition apparatus and processing method for performing three-dimensional magnetic resonance imaging in a static magnetic field without the application of controlled static magnetic field gradients. A preferred application relates specifically to the detection and localization of groundwater using the Earth's magnetic field. Multicoil arrays are used in both transmit and receive modes, and coherent data processing algorithms applied to the data to generate three-dimensional NMR spin density estimates. Disclosed are methods for acquiring NMR data using an array of at least two transmit and receive coils, and for processing such multicoil data to estimate the three-dimensional NMR spin density distributions.
Claims14
A method of constructing a 3-dimensional nuclear magnetic resonance image of at least a portion of a target without generating gradients in a static magnetic field, comprising:
- a) relying upon environmentally innate static magnetic field gradients and using a plurality of magnetic field generating coils with spatially distinct magnetic field patterns, transmitting alternating magnetic field pulses at the Larmor frequency of the target using a plurality of linearly independent combinations of relative current amplitudes and/or phases among the transmitting coils, and using P different values of total transmitted energy for each combination of transmit coils used, where P>1;
- b) using a plurality of magnetic field receiving coils with spatially distinct magnetic field patterns, detecting and recording a set of nuclear magnetic resonance signals arising from each transmit pulse, each of the set of nuclear magnetic resonance signals comprising a plurality of samples;
- c) arranging the set of recorded nuclear magnetic resonance data samples as a vector b;
- and
- d) reconstructing a 3-dimensional nuclear magnetic resonance image wherein each sampled location in the 3-dimensional image space is assigned a scalar value s, wherein the scalar value s is computed as a weighted linear combination of the recorded data samples b:
- s=Σjwjbj
Dependencies are inferred from the claim text.