Invasive device for use in a magnetic resonance imaging apparatus

Claim 2

An invasive device to be introduced into an object being imaged with a magnetic resonance imaging apparatus comprising: an elongate envelope which has a distal end and a proximal end, one or more RF coils which are arranged in the envelope, an electric connection for coupling the one or more RF coils to a control unit, and a hollow carrier which is in the envelope and which has a distal end and a proximal end, the electric connection extending through said hollow carrier, said hollow carrier comprising an electrically conductive shield which extends over a distance from the distal end to the proximal end of the hollow carrier, and which has an electric resistance over said distance which is substantially higher than the electric resistance of the electric connection over the same distance.

Claim 3

An invasive device as claimed in claim 1, wherein the electric shield comprises alternately, from the distal end to the proximal end, electrically highly conductive portions and electrically less conductive portions.

Claim 4

An invasive device as claimed in claim 2, wherein electrically less conductive portions are formed as interruptions in the shield.

Claim 5

An invasive device as claimed in claim 2, wherein the electrically conductive shield comprises a flexible material.

Claim 6

An invasive device as claimed in claim 2, wherein the electrically conductive shield comprises a conductive synthetic material.

Claim 7

An invasive device as claimed in claim 1, wherein the shield comprises a material which is uniformly distributed across the length of the shield and has a specific resistance which is substantially higher than a specific resistance of a material constituting the electric connection.

Claim 8

An invasive device as claimed in claim 6, wherein the electrically conductive shield comprises a flexible material.

Claim 9

An invasive device as claimed in claim 1, wherein the electrically conductive shield comprises a flexible material.

Claim 10

An invasive device as claimed in claim 8, wherein the electrically conductive shield comprises a conductive synthetic material.

Claim 11

An invasive device as claimed in claim 1, wherein the electrically conductive shield comprises a conductive synthetic material.

Claim 12

An invasive device as claimed in claim 1 wherein the electric connection comprises coaxial conductors.

Claim 13

An invasive device as claimed in claim 1, wherein at least one of the one or more RF coils is arranged near the distal end of the envelope.

Claim 14

An invasive device as claimed in claim 1, wherein the hollow carrier encloses the one or more RF coils and the electrical connection.

Claim 15

A magnetic resonance apparatus for imaging an object with an introduced invasive device comprising: a first magnet system for generating a static magnetic field in the object, a plurality of gradient coils for generating gradient magnetic fields in the object, one of more RF coils for transmitting RF pulses to the object and for receiving RF signals from the object, and a control unit for controlling the gradient magnetic fields and the RF pulses in order to generate magnetic resonance imaging signals, and an invasive device comprising an elongate envelope which is adapted to be introduced into the object, one or more receiving coils which are arranged in the envelope and which are for receiving the RF pulses, an electric connection for coupling the one or more receiving coils to an invasive-device control unit, and a hollow carrier which is in the envelope and which has a distal end and a proximal end, the electric connection extending through said hollow carrier, said hollow carrier comprising an electrically conductive shield which extends over a distance from the distal end to the proximal end of the hollow carrier, and which has an electric resistance over said distance which is substantially higher than the electric resistance of the electric connection over the same distance.

Claim 16

A magnetic resonance apparatus for imaging an object with an introduced invasive device comprising: a first magnet system for generating a static magnetic field in the object, a plurality of gradient coils for generating gradient magnetic fields in the object, one of more RF coils for transmitting RF pulses to the object and for receiving RF signals from the object, and a control unit for controlling the gradient magnetic fields and the RF pulses in order to generate magnetic resonance imaging signals, and an invasive device comprising an elongate envelope which is adapted to be introduced into the object, one or more receiving coils which are arranged in the envelope and which are for receiving the RF pulses, an electric connection for coupling the one or more receiving coils to an invasive-device control unit, and a hollow carrier which is in the envelope and which has a distal end and a proximal end, the electric connection extending through said hollow carrier, said hollow carrier comprising an electrically conductive shield which extends over a distance from the distal end to the proximal end of the hollow carrier, and which has an electric resistance over said distance which is substantially higher than the electric resistance of the electric connection over the same distance.

Claim 17

The magnetic resonance imaging apparatus of claim 14 wherein the electrically conductive shield of the invasive device further comprises alternately, from the distal end to the proximal end of the hollow carrier, electrically highly conductive portions and electrically less conductive portions, and wherein the distance between the successive electrically less conductive portions is smaller than or equal to 1/4 wavelength of the RF pulses transmitted to the object.

Claim 18

An invasive device as claimed in claim 15, wherein the electrically less conductive portions are formed as interruptions in the shield.

Claim 19

An invasive device as claimed in claim 16, wherein the electrically conductive shield comprises a flexible material.

Claim 20

An invasive device as claimed in claim 16, wherein the electrically conductive shield comprises a conductive synthetic material.

Claim 21

An invasive device as claimed in claim 14, wherein the electrically conductive shield comprises a flexible material.

Claim 22

An invasive device as claimed in claim 14, wherein the electrically conductive shield comprises a conductive synthetic material.