Variable aperture, variable frequency extremity coil for magnetic resonance imaging

Claim 2

An extremity coil for magnetic resonance imaging comprising: a plurality of columns disposed about a main axis, said columns being electrically connected to each other at their first ends and said columns being electrically connected to each other at their second ends; means for varying the distance of the columns from the main axis; and means for supporting the coil.

Claim 3

An extremity coil as described in claim 1 wherein the varying means includes a driver plate disposed in a plane that is essentially perpendicular to the main axis with the main axis essentially passing through the center of the driver plate, said driver plate having a plurality of slots which extend from a location near the main axis and which are coaxial to the main axis, said second ends of the columns extending into corresponding slots of the driver plate; an end ring disposed in a plane that is essentially perpendicular to the main axis with the main axis essentially passing through the center of the end ring; a plurality of spokes, each of said spokes extend from a location near the main axis and are attached to the end ring such that each spoke is able to swing in a plane that is essentially perpendicular to the main axis, said first ends of the columns attached to corresponding spokes.

Claim 4

An extremity coil as described in claim 2 wherein the support means includes a main support plate and a first and second support ring attached to the main support plate, said first and second support rings disposed about the columns such that they support the columns.

Claim 5

An extremity coil for magnetic resonance imaging comprising: a main cylinder having a first plurality of slots extending lengthwise into the main cylinder from a first end thereof; a driver plate, disposed in the main cylinder at the first end thereof and disposed essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the driver plate, said driver plate capable of sliding along the first plurality of slots in the main cylinder, said first plurality of slots capable of preventing the driver plate from independently rotating about the main axis, said driver plate having slots which extend from a location near the main axis and which are coaxial to the main axis; an end ring disposed in the main cylinder at a second end thereof, and disposed in a plane that is essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the end ring; a plurality of spokes which extend from a location near the main axis and which are coaxial to the main axis, each of said spokes being attached to the end ring such that each spoke is able to swing in a plane that is perpendicular to the main axis; a plurality of columns disposed in the main cylinder and are coaxial to the main axis thereof, said columns extendable with respect to the length and having a capacitance corresponding thereto for tuning the resonant frequency of the coil, each column having a first end attached to a corresponding spoke, and a second end extending into a corresponding slot of the driver plate, the first ends of each column being electrically connected to each other and second ends of each column being electrically connected to each other; and means for supporting the main cylinder.

Claim 6

An extremity coil for magnetic resonance imaging comprising: a main cylinder having a first plurality of slots extending lengthwise into the main cylinder from a first end thereof; a driver plate, disposed in the main cylinder at the first end thereof and disposed essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the driver plate, said driver plate capable of sliding along the first plurality of slots in the main cylinder, said first plurality of slots capable of preventing the driver plate from independently rotating about the main axis, said driver plate having slots which extend from a location near the main axis and which are coaxial to the main axis; an end ring disposed in the main cylinder at a second end thereof, and disposed in a plane that is essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the end ring; a plurality of spokes which extend from a location near the main axis and which are coaxial to the main axis, each of said spokes being attached to the end ring such that each spoke is able to swing in a plane that is perpendicular to the main axis; a plurality of columns disposed in the main cylinder and are coaxial to the main axis thereof, said columns extendable with respect to the length and having a capacitance corresponding thereto for tuning the resonant frequency of the coil, each column having a first end attached to a corresponding spoke, and a second end extending into a corresponding slot of the driver plate, the first ends of each column being electrically connected to each other and second ends of each column being electrically connected to each other; and means for supporting the main cylinder.

Claim 7

An extremity coil as described in claim 4 wherein the main cylinder has a second plurality of slots at the second end thereof, each of said spokes extend from a location near the main axis into a corresponding slot of the second plurality of slots.

Claim 8

An extremity coil as described in claim 5 wherein the first ends of the columns are electrically connected to each other by a first connecting ring comprised of flexible inductors, with a flexible inductor connected to the first ends of adjacent columns, and wherein the second ends of the columns are electrically connected to each other by a second connecting ring comprised of flexible inductors, with a flexible inductor connected to the second ends of adjacent columns.

Claim 9

An extremity coil as described in claim 6 wherein each column includes an electrically conducting rod and an electrically conducting tube, said rod is disposed in said tube and forms a capacitance therebetween, said capacitance is capable of being varied.

Claim 10

An extremity coil as described in claim 7 wherein the means for supporting the cylinder includes a main support plate and a first and second support ring attached to the main support plate, said first and second support rings disposed about the main cylinder such that the main cylinder is rotatably supported by the first and second support rings.

Claim 11

An extremity coil as described in claim 8 wherein the driver plate has a plurality of tabs, each of said tabs extending through a corresponding slot of the first plurality of slots in the main cylinder; and there is included a driver cylinder disposed about the main cylinder and connected to the tabs such that the driver cylinder can rotate and slide in concert with the driver plate.

Claim 12

An extremity coil as described in claim 9 including a rack and pinion mechanism attached to the main cylinder for rotating the main cylinder.

Claim 13

An extremity coil for magnetic resonance imaging comprising: a main cylinder having a first plurality of slots extending lengthwise into the main cylinder from a first end thereof, and a second plurality of slots disposed at a second end thereof; a driver plate, disposed in the main cylinder at the first end thereof and disposed essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the driver plate, said driver plate capable of sliding along the first plurality of slots in the main cylinder, said first plurality of slots capable of preventing the driver plate from independently rotating about the main axis, said driver plate having slots which extend from a location near the main axis and which are coaxial to the main axis, said driver plate having a plurality of tabs, each of said tabs extending through a corresponding slot of the first plurality of slots in the main cylinder; a driver cylinder disposed about the main cylinder and connected to the tabs such that the driver cylinder can rotate and slide in concert with the driver plate; an end ring disposed in the main cylinder at the second end thereof, and disposed in a plane that is essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the end ring; a plurality of spokes which extend from a location near the main axis and which are coaxial to the main axis, each of said spokes attached to the end ring such that each spoke is able to swing in a plane that is essentially perpendicular to the main axis, each of said spokes extend from a location near the main axis into a corresponding slot of the second plurality of slots; a plurality of columns disposed in the main cylinder and are coaxial to the main axis thereof, said columns extendable with respect to length, and having a capacitance corresponding thereto for tuning the resonant frequency of the coil, each column having a first end attached to a corresponding spoke, and a second end extending into a corresponding slot of the driver plate, the first ends of each column being electrically connected to each other by a first connecting ring comprised of flexible inductors, with a flexible inductor connected to the first ends of adjacent columns, and second ends of each column being electrically connected to each other by a second connecting ring comprised of flexible inductors, with a flexible inductor connected to the second ends of adjacent columns, each column includes an electrically conducting rod and an electrically conducting tube, said rod is disposed in said tube and forms a capacitance therebetween, said capacitance is capable of being varied; a main support plate; and a first and second support ring attached to the main support plate, said first and second support rings disposed about the main cylinder such that the main cylinder is rotatably supported by the first and second support rings.

Claim 14

An extremity coil for magnetic resonance imaging comprising: a main cylinder having a first plurality of slots extending lengthwise into the main cylinder from a first end thereof, and a second plurality of slots disposed at a second end thereof; a driver plate, disposed in the main cylinder at the first end thereof and disposed essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the driver plate, said driver plate capable of sliding along the first plurality of slots in the main cylinder, said first plurality of slots capable of preventing the driver plate from independently rotating about the main axis, said driver plate having slots which extend from a location near the main axis and which are coaxial to the main axis, said driver plate having a plurality of tabs, each of said tabs extending through a corresponding slot of the first plurality of slots in the main cylinder; a driver cylinder disposed about the main cylinder and connected to the tabs such that the driver cylinder can rotate and slide in concert with the driver plate; an end ring disposed in the main cylinder at the second end thereof, and disposed in a plane that is essentially perpendicular to the main axis of the main cylinder with the main axis passing through the center of the end ring; a plurality of spokes which extend from a location near the main axis and which are coaxial to the main axis, each of said spokes attached to the end ring such that each spoke is able to swing in a plane that is essentially perpendicular to the main axis, each of said spokes extend from a location near the main axis into a corresponding slot of the second plurality of slots; a plurality of columns disposed in the main cylinder and are coaxial to the main axis thereof, said columns extendable with respect to length, and having a capacitance corresponding thereto for tuning the resonant frequency of the coil, each column having a first end attached to a corresponding spoke, and a second end extending into a corresponding slot of the driver plate, the first ends of each column being electrically connected to each other by a first connecting ring comprised of flexible inductors, with a flexible inductor connected to the first ends of adjacent columns, and second ends of each column being electrically connected to each other by a second connecting ring comprised of flexible inductors, with a flexible inductor connected to the second ends of adjacent columns, each column includes an electrically conducting rod and an electrically conducting tube, said rod is disposed in said tube and forms a capacitance therebetween, said capacitance is capable of being varied; a main support plate; and a first and second support ring attached to the main support plate, said first and second support rings disposed about the main cylinder such that the main cylinder is rotatably supported by the first and second support rings.