Magnetic resonance imaging probe

• US 7,848,788 B2
• Filed: 04/11/2002
• Issued: 12/07/2010
• Est. Priority Date: 04/15/1999
• Status: Active Grant

• Current Assignee: Johns Hopkins University, SurgiVision Inc.
• Original Assignee: Johns Hopkins University, SurgiVision Inc.
• Inventors: Karmarkar, Parag, Yang, Xiaoming, McVeigh, Elliot, Tulley, Steve, McNamara, Christine Enger, Lardo, Albert C., Halperin, Henry R., Atalar, Ergin, Bottomley, Paul A.
• Primary Examiner(s): Smith; Ruth S
• Application Number:
  US10/123,065
• Publication Number:
  US 20030028095A1
• Time in Patent Office: 3,162 Days
• Field of Search: 600/410, 600421-423, 324/307, 324/309, 324/318, 324/322
• US Class Current: 600/423
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: G01R 33/287 involving active visualization of interventional instruments, e.g. using active tracking RF coils or coils for intentionally creating magnetic field inhomogeneities
• CPC Class Codes: G01R 33/34053 Solenoid coils; Toroidal coils
• CPC Class Codes: G01R 33/34084 implantable coils or coils being geometrically adaptable to the sample, e.g. flexible coils or coils comprising mutually movable parts
• CPC Class Codes: G01R 33/3657 Decoupling of multiple RF coils wherein the multiple RF coils do not have the same function in MR, e.g. decoupling of a transmission coil from a receive coil
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 1/40 Radiating elements coated with or embedded in protective material
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 1/44 using equipment having another main function to serve additionally as an antenna , e.g. means for giving an antenna an aesthetic aspectH01Q1/27 - H01Q1/34 take precedence
• CPC Class Codes: H01Q 11/08 Helical antennas

Abstract

Herein is disclosed a magnetic resonance imaging probe, having a probe shaft including a magnetic resonance antenna, and a spring tip attached to a distal end of the antenna.

Claims

1. A magnetic resonance imaging probe, comprising:

a probe shaft having a magnetic resonance antenna, the probe shaft comprising

a core of non-magnetic material;

a first insulator/dielectric covering the core;

a shield layer covering the first insulator/dielectric;

a proximal spring assembly coupled to a distal end of the shield layer and configured and arranged to act with the shield layer as a coaxial shield; and

a magnetic resonance imaging coil conductively attached to the core and forming a part of the magnetic resonance antenna;

a spring tip having increased flexibility relative to the probe shaft proximate the antenna; and

an electrically insulating material affixing the spring tip to a distal end of the probe shaft and preventing electrical conduction between the spring tip and the imaging coil.

2. The probe of claim 1, wherein the core comprises a Nitinol wire and alternating layers of gold, silver, and gold, surrounding at least a portion of the Nitinol wire.

3. The probe of claim 1, wherein the probe shaft further comprises a second insulator/dielectric disposed over the shield layer.

4. The probe of claim 1, wherein the core of non-magnetic material is plated with alternating layers of gold and silver.

5. The probe of claim 1, wherein the core comprises a central core having at least one of carbon, glass fiber, and a polymer, and the core further comprises a radio frequency conductive covering surrounding the central core.

6. The probe of claim 5, wherein the covering comprises alternating layers of gold, silver, and gold, surrounding the central core.

7. The probe of claim 1, wherein the spring tip is attached to the imaging coil by an adhesive joint.

8. The probe of claim 1, wherein the imaging coil comprises a helical whip with a proximate end and a distal end, the helical whip having coils with a diameter and a spacing, and wherein the distal end of the helical whip is connected to the spring tip.

9. The probe of claim 8, wherein the helical whip is covered by a biocompatible material or covering.

10. The probe of claim 9, wherein an electrical length of the imaging coil is chosen so as to compensate for the biocompatible material or covering.

11. The probe of claim 1, wherein the probe is sized and shaped to be a guidewire.

12. The probe of claim 1, further comprising a connector coupled to a proximal end of the probe shaft.

13. The probe of claim 12, wherein the connector is removably coupled to the proximal end of the probe shaft.

14. The probe of claim 12, wherein the connector couples to an interface.

15. The probe of claim 14, wherein the interface comprises at least one of a tuning-matching circuit, a balun circuit, a decoupling circuit, or a variable capacitor.

16. The probe of claim 1, wherein the antenna comprises a loopless antenna.

17. The probe of claim 1, wherein the spring tip further comprises a ribbon extending from the spring tip to the core.

18. The probe of claim 1, wherein an outer surface of the probe shaft is insulated with a biocompatible material or coating.

19. The probe of claim 1, further comprising a cover layer covering at least a portion of the probe shaft.

20. The probe of claim 1, wherein the probe is sized and shaped for intravascular use.

21. A magnetic resonance imaging probe, comprising:

a core of non-magnetic material;

a shield layer having a distal end and surrounding at least a part of the core;

a proximal spring assembly having a distal end and being conductively coupled to the distal end of the shield layer and configured and arranged to act with the shield layer as a coaxial shield;

a joining segment attached to the distal end of the proximal spring assembly;

a magnetic resonance imaging coil attached to the joining segment; and

a spring tip attached to a distal end of the imaging coil.

22. The imaging probe of claim 21, wherein the proximal spring assembly comprises a round winding wire.

23. The imaging probe of claim 22, wherein the round winding wire is stacked.

24. A magnetic resonance imaging probe, comprising:

a core of non-magnetic material;

a first insulator/dielectric surrounding at least a part of the core;

a shield layer surrounding at least a part of the first insulator/dielectric and having a distal end;

a modified shield layer attached to the distal end of the shield layer and having a distal end;

a proximal spring assembly conductively coupled to the distal end of the modified shield layer and configured and arranged to act with the shield layer and modified shield layer as a coaxial shield, the proximal spring assembly having a distal end, wherein the modified shield layer provides a region of stiffness transition from the shield layer to the proximal spring assembly;

a joining segment attached to the distal end of the proximal spring assembly;

a magnetic resonance imaging coil attached to the joining segment and conductively coupled to the core, the imaging coil having a distal end; and

a spring tip attached to the distal end of the imaging coil.

25. A magnetic resonance imaging probe, comprising:

a core of non-magnetic material;

a first insulator/dielectric surrounding at least a part of the core;

a shield layer surrounding at least a part of the first insulator/dielectric and having a distal end;

a modified shield layer attached to the distal end of the shield layer and having a distal end;

a joining segment attached to the distal end of the modified shield layer;

a magnetic resonance imaging coil attached to the joining segment, conductively coupled to the core, and having a distal end; and

a spring tip attached to the distal end of the imaging coil, wherein the modified shield layer provides a region of stiffness transition from the shield layer to the spring tip.

26. A magnetic resonance imaging probe system, comprising:

a magnetic resonance imaging probe, having;

a probe shaft including a distal end and a proximal end, the probe shaft further including;

a core of non-magnetic material;

a first insulator/dielectric covering the core;

a shield layer covering the first insulator/dielectric and having a distal end;

a proximal spring assembly conductively coupled to the distal end of the shield layer and having a distal end and configured and arranged to act with the shield layer as a coaxial shield; and

a magnetic resonance imaging coil non-conductively coupled to the distal end of the proximal spring assembly and conductively coupled to the core, the imaging coil having a distal end;

a spring tip;

an electrically insulating material affixing the spring tip to the distal end of the probe shaft and preventing electrical conduction between the spring tip and the imaging coil; and

a connector attached to the proximal end of the probe shaft; and

an interface, having;

a balun circuit;

a decoupling circuit in electrical communication with at least one of the balun circuit or a tuning/matching circuit;

the tuning/matching circuit in electrical communication with at least one of the balun circuit or the decoupling circuit;

a proximal connector, in electrical communication with at least one of the balun circuit, the decoupling circuit, or the tuning/matching circuit, the proximal connector being adapted for removable electrical connection to a magnetic resonance scanner; and

a distal connector, in electrical communication with at least one of the balun circuit, the decoupling circuit, or the tuning/matching circuit, the connector of the interface being adapted for removable electrical connection to the connector of the imaging probe.