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US 5,557,247 AGranted
Radio frequency volume coils for imaging and spectroscopy
AssigneeThe UAB Research Foundation
InventorJohn T. Vaughn, Jr.
Life of this patent
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AssigneeThe UAB Research Foundation
InventorJohn T. Vaughn, Jr.
Estimating the term…
A distributed impedance circuit MR coil design comprised of a transmission line tunable cavity resonator which is well suited for but not limited to use at high frequencies and for large volumes such as in high field (e.g. 4.1 tesla) clinical MR applications. The distributed circuit transmission line resonator is designed for high frequency, large conductive volume applications where conventional lumped element coil designs fail. A resonant coaxial cavity is variably tuned to the Larmor frequency of interest by tunable transmission line elements. The resonator is effective for large head and body sized volumes, high efficiencies, and broad tuning ranges to frequencies of 500 MHz. The B.sub.1 homogeneity of the resonator is a function of the electromagnetic properties of the load itself. Maxwell's equations for the fully time-dependent B.sub.1 field predicts "coil" homogeneity with finite-element models of anatomic structure. Coil design and construction, and methods of quadrature driving and double tuning the transmission line resonator, are set forth.
An MR RF coil in the form of a tuned TEM resonator, said resonator having a cavity and a set of transmission line segments, and there being circuit means including said set for providing a tunable high frequency magnetic field within said cavity;
An MR RF coil in the form of a TEM resonator, said resonator having a cavity and a set of transmission line segments, and there being circuit means including said set for providing a high frequency magnetic field within said cavity;
A k frequencies MR RF coil in the form of a TEM Resonator comprising a set of elements, each said element having uniformly distributed impedance along its length, said set being arranged to create a magnetic field within a cavity incorporating said set, and circuit means incorporating k subsets of said elements for causing each subset of elements to create a magnetic field having a frequency corresponding to the collective distributed impedance of the elements of such subset, k being an integer equal to or greater than one, whereby said coil is capable of resonance greater than 4 Tesla.
A dual frequency MR RF coil comprising a cavity having transmission line elements for determining resonant frequencies of said cavity;
Dependencies are inferred from the claim text.