SYSTEM, METHOD, AND APPARATUS FOR MAGNETIC RESONANCE RF-FIELD MEASUREMENT
First Claim
1. A magnetic resonance imaging (MRI) apparatus comprising:
- a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images; and
a computer programmed to;
apply a first off-resonant radio frequency (RF) pulse at a first frequency to a plurality of nuclei excited at a resonant frequency, wherein the first frequency is different than the resonant frequency;
acquire a first signal from the plurality of nuclei after application of the first off-resonant RF pulse;
determine a phase shift from the first signal, wherein the phase shift is based on the first off-resonant RF pulse;
determine a B1 field based on the phase shift; and
store the B1 field on a computer readable storage medium.
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Accused Products
Abstract
An apparatus, system, and method including a magnetic resonance imaging (MRI) apparatus includes a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images, and a computer. The computer is programmed to apply a first off-resonant radio frequency (RF) pulse at a first frequency different than the resonant frequency to a plurality of nuclei excited at a resonant frequency, acquire a first signal from the plurality of nuclei after application of the first off-resonant RF pulse, determine a phase shift from the first signal based on the first off-resonant RF pulse, determine a B1 field based on the phase shift, and store the B1 field on a computer readable storage medium.
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Citations
21 Claims
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1. A magnetic resonance imaging (MRI) apparatus comprising:
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a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet, and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images; and a computer programmed to; apply a first off-resonant radio frequency (RF) pulse at a first frequency to a plurality of nuclei excited at a resonant frequency, wherein the first frequency is different than the resonant frequency; acquire a first signal from the plurality of nuclei after application of the first off-resonant RF pulse; determine a phase shift from the first signal, wherein the phase shift is based on the first off-resonant RF pulse; determine a B1 field based on the phase shift; and store the B1 field on a computer readable storage medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A computer readable storage medium having stored thereon a computer program comprising instructions which when executed by a computer cause the computer to:
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cause a pulse generator to apply a first off-resonant radio frequency (RF) pulse to a plurality of excited nuclei, the first off-resonant RF pulse configured to shift a resonant frequency of the plurality of nuclei; receive a first signal from the plurality of excited nuclei via at least one magnetic resonant (MR) receive coil after application of the first off-resonant RF pulse; determine a phase shift induced by the first off-resonant RF pulse; determine a B1 field based on the phase shift; and store the B1 field on a storage device coupled to an MR imaging apparatus. - View Dependent Claims (14, 15, 16)
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17. A method of determining a magnetic field comprising:
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shifting a resonating frequency of a plurality of nuclei after the plurality of nuclei are excited at a first resonating frequency; acquiring a first signal with a magnetic resonance (MR) receive coil from the plurality of nuclei after shifting the resonating frequency; determining a phase shift based on the first signal; and storing the phase shift on a computer readable storage medium coupled to an MR apparatus. - View Dependent Claims (18, 19, 20, 21)
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Specification