Multicoil NMR data acquisition and processing methods
AssigneeVista Clara Inc.
InventorDavid O. Walsh
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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.
Claims18
A method of obtaining a localized nuclear magnetic resonance signal from a sample in a static magnetic field using an array of two or more magnetic field transmitting coils, and an array of two or more magnetic field receiving coils, comprising:
- a) generating a single alternating current excitation pulse on one or more transmitting coils, each of said transmitting coils providing a spatially distinct inhomogeneous field;
- b) acquiring NMR signals on two or more magnetic field receiving coils;
- c) applying a plurality of excitation pulses to each transmitting coil or combination of transmitting coils, wherein each excitation pulse has a unique pulse moment defined as the product of the pulse amplitude and pulse length, and wherein the nth pulse moment PM(n) is not equal to (2n−1)*PM(1);
- and
- d) constructing a localized nuclear magnetic resonance signal as a linear combination of NMR signals obtained using two or more transmitting coils or combinations of transmitting coils, two or more receiving coils, and two or more pulse moments for each transmitting coil.
Dependencies are inferred from the claim text.