Using S-parameter measurements to manage SAR and transmit gain in MRI
First Claim
1. A magnetic resonance imaging system comprising:
- a radio frequency coil having a plurality of conductive coil elements;
control circuitry configured to determine a plurality of forward voltages using an unloaded measurement of scattering parameters and a loaded measurement of scattering parameters, wherein the unloaded measurement of scattering parameters is obtained when an object is not in the magnetic resonance imaging system and the loaded measurement of scattering parameters is obtained when the object is in the magnetic resonance imaging system, and wherein the plurality of forward voltages cause a deposition of power into the object when the forward voltages are applied respectively to the plurality of coil elements, wherein the deposition of power is within a predetermined specific absorption rate; and
a radio frequency coil amplifier configured to apply the determined plurality of forward voltages respectively to the plurality of coil elements in order to cause the deposition of power into the object.
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Accused Products
Abstract
Systems and methods for controlling a magnetic resonance imaging system are provided. In one embodiment, a magnetic resonance imaging system includes a radio frequency coil with a plurality of conductive coil elements, control circuitry that determines, based at least in part on a measurement of scattering parameters, a plurality of forward voltages that will cause power deposition into an object within a predetermined specific absorption rate, and an amplifier configured to apply the determined plurality of forward voltages respectively to the plurality of coil elements. The control circuitry may determine the plurality of forward voltages based at least in part on an unloaded measurement of scattering parameters and a loaded measurement of scattering parameters.
22 Citations
18 Claims
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1. A magnetic resonance imaging system comprising:
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a radio frequency coil having a plurality of conductive coil elements; control circuitry configured to determine a plurality of forward voltages using an unloaded measurement of scattering parameters and a loaded measurement of scattering parameters, wherein the unloaded measurement of scattering parameters is obtained when an object is not in the magnetic resonance imaging system and the loaded measurement of scattering parameters is obtained when the object is in the magnetic resonance imaging system, and wherein the plurality of forward voltages cause a deposition of power into the object when the forward voltages are applied respectively to the plurality of coil elements, wherein the deposition of power is within a predetermined specific absorption rate; and a radio frequency coil amplifier configured to apply the determined plurality of forward voltages respectively to the plurality of coil elements in order to cause the deposition of power into the object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A magnetic resonance imaging system comprising:
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a radio frequency coil assembly configured to obtain an unloaded measurement of scattering parameters and a loaded measurement of scattering parameters, wherein the unloaded measurement of scattering parameters is obtained when an object is not in the magnetic resonance imaging system and the loaded measurement of scattering parameters is obtained when the object is in the magnetic resonance imaging system; and where the loaded and unloaded measurements of scattering parameters, permit forward and/or reflected voltages of the radiofrequency coil assembly to be determined. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A magnetic resonance imaging system comprising:
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a radio frequency coil; an amplifier configured to drive the radio frequency coil with at least one of a forward and/or reflected voltage based on a control signal; and control circuitry operably connected to the amplifier and configured to provide the control signal to the amplifier, the control circuitry capable of; receiving an unloaded measurement of scattering parameters of the radio frequency coil obtained when an object is not within the radio frequency coil; receiving a loaded measurement of scattering parameters of the radio frequency coil obtained when the object is within the radio frequency coil; and determining the control signal, using the unloaded measurement of scattering parameters and the loaded measurement of scattering parameters, that is predicted to cause the amplifier to drive the radio frequency coil to deposit an amount of power into the object when the object is within the radio frequency coil, wherein the amount of power into the object is within a predetermined specific absorption rate. - View Dependent Claims (15, 16, 17, 18)
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Specification