I claim as my invention:
1. A magnetic resonance device, comprising:
a basic field magnet to generate a basic magnetic field that exhibits, within an imaging volume of the magnetic resonance device, a main component optimally and exclusively oriented in a predeterminable direction;
at least one gradient coil arranged in a region of a gradient magnetic field in which the basic magnetic field exhibits at least one secondary component perpendicular to the main component; and
conductors of the gradient coil arranged such that, given flow of an electrical current in the conductors, a turning moment operating via the main component and affecting a part of the gradient coil is at least partially compensated by a turning moment acting via the secondary component.
2. The magnetic resonance device according to claim 1 wherein the main component and the secondary component exhibit a comparable magnitude in the region of the conductors.
3. The magnetic resonance device according to claim 1 wherein the conductors are arranged in a substantially hollow cylindrical region.
4. The magnetic resonance device according to claim 3 wherein the main component is oriented in a direction of a hollow-cylinder main axis of the hollow-cylindrical region.
5. The magnetic resonance device according to claim 3 wherein the gradient coil is partitioned into two sub-coils in an axial direction of the hollow-cylindrical region.
6. The magnetic resonance device according to claim 5 wherein a spatial curve of the secondary component in the axial direction in a region of the conductor of one of the sub-coils exhibits a change of sign.
7. The magnetic resonance device according to claim 5 wherein at least one of the sub-coils is designed with regard to its focal point to compensate turning moments.
8. The magnetic resonance device according to claim 5 wherein the conductors of at least one of the sub-coils are arranged such that, given flow of the electrical current in the conductors, forces operating on the conductors perpendicular to the axial direction at least partially counter each other.
9. The magnetic resonance device according to claim 3 wherein the gradient coil comprises a transversal gradient coil.
10. The magnetic resonance device according to claim 1 wherein the gradient coil comprises an actively shielded gradient coil.
11. The magnetic resonance device according to claim 10 wherein the actively shielded gradient coil comprises a primary coil and a shielding coil.
12. A magnetic resonance device, comprising:
a basic field magnet to generate a basic magnetic field that exhibits, within an imaging volume of the magnetic resonance device, a main component oriented in a predeterminable direction;
at least one gradient coil arranged in a region of a gradient magnetic field in which the basic magnetic field exhibits at least one secondary component perpendicular to the main component; and
conductors of the gradient coil arranged such that, given flow of an electrical current in the conductors, a turning moment operating via the main component and affecting at least a part of the gradient coil is at least partially compensated by a turning moment acting via the secondary component.
13. A method for compensating for a turning moment effecting at least a part of a gradient coil in a magnetic resonance device, comprising the steps of:
providing in the magnetic resonance device a basic magnetic field magnet which generates a basic magnetic field that exhibits, within an imaging volume of the magnetic resonance device, a main component oriented in a predeterminable direction;
arranging the gradient coil in a region of a gradient magnetic field in which the basic magnetic field exhibits at least one secondary component perpendicular to the main component; and
arranging conductors of the gradient coil such that, given flow of an electrical current in the conductors, the turning moment caused by the main component and which effects a part of the gradient coil is at least partially compensated by a turning moment acting via the secondary component.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An intra myocardial injector which comprises:
a catheter having a distal end, said catheter being formed with a lumen defining a longitudinal axis;
an abutment member having a distal portion and a proximal portion, wherein the abutment member is movable between a first configuration and a second configuration wherein in its first configuration the abutment member is substantially tube-shaped and is positioned within the lumen of the catheter and in its second configuration the proximal portion remains in the lumen of the catheter while the distal portion of the abutment member extends axially beyond the distal end of the catheter and is flared radially outward to establish an annular-shaped barrier at a distal extreme of the abutment member;
a pusher rod for axially moving the abutment member between the first configuration and the second configuration; and
a needle having a tip, said needle being positioned within the lumen of the catheter for a linear advancement of the needle tip beyond the distal end of the catheter and beyond the barrier provided by the distal portion of the abutment member to penetrate myocardial tissue to perform an injection, when said abutment member is in its second configuration and the annular-shaped barrier abuts the myocardial tissue to prevent contact between said catheter and the myocardial tissue and prevent further distal movement of the catheter during the infection.
2. An injector as recited in claim 1 wherein the abutment member is comprised of wire formed from a nickel-titanium alloy.
3. An injector as recited in claim 2 wherein the abutment member is formed from loops of the nickel-titanium wire.
4. An injector as recited in claim 3 wherein the abutment member includes engagement elements on the loops of the wire.
5. An injector as recited in claim 3 wherein a webbing interconnects the loops of the nickel-titanium wire.
6. An injector as recited in claim 1 wherein the pusher rod engages the proximal portion of the abutment member to axially move the abutment member between the first configuration and the second configuration.
7. An intra myocardial injector which comprises:
a catheter having a distal end, said catheter being formed with a lumen defining a longitudinal axis;
an abutment member having a distal portion and a proximal portion, movable between a first configuration and a second configuration wherein in its first configuration the abutment member is substantially tube-shaped and is positioned within the lumen of the catheter and in its second configuration the proximal portion remains in the lumen of the catheter while the distal portion of the abutment member extends axially beyond the distal end of the catheter and is flared radially outward to establish an annular-shaped barrier a distal extreme of the abutment member;
a pusher rod having a distal end, with said pusher rod being mounted within the lumen of the catheter for axial movement therein, and with said distal end of the pusher rod engaging the proximal portion of the abutment member to move the abutment member between the first configuration and the second configuration; and
a needle having a tip, said needle being positioned within the lumen of the catheter for a linear advancement of the needle tip beyond the distal end of the catheter and beyond the barrier provided by the distal portion of the abutment member to penetrate myocardial tissue to perform an injection, when said abutment member is in its second configuration and the annular-shaped barrier abuts the myocardial tissue to prevent contact between said catheter and the myocardial tissue and prevent further distal movement of the catheter during the injection.
8. An injector as recited in claim 7 wherein the abutment member is comprised of wire formed from a nickel-titanium alloy.
9. An injector as recited in claim 8 wherein the abutment member is formed from loops of the nickel-titanium wire.
10. An injector as recited in claim 9 wherein the abutment member includes engagement members on the loops of wire.
11. An injector as recited in claim 9 wherein a webbing interconnects the loops of the nickel-titanium wire.
12. An injector as recited in claim 7 wherein the pusher rod engages the proximal portion of the abutment member to axially move the abutment member between the first configuration and the second configuration.