Imaging fiducial markers and methods

• US 9,861,450 B2
• Filed: 12/11/2015
• Issued: 01/09/2018
• Est. Priority Date: 11/17/2005
• Status: Active Grant

• Current Assignee: Breast-Med, Inc.
• Original Assignee: Breast-Med, Inc.
• Inventors: Bolan, Patrick, Garwood, Michael G., Nelson, Michael T., Halpern, Daniel A.
• Primary Examiner(s): Koehler, Christopher M
• Application Number:
  US14/966,400
• Publication Number:
  US 20160100910A1
• Time in Patent Office: 760 Days
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 2090/3908 Soft tissue, e.g. breast tissue
• CPC Class Codes: A61B 2090/3925 ultrasonic
• CPC Class Codes: A61B 2090/3954 magnetic, e.g. NMR or MRI
• CPC Class Codes: A61B 2090/3958 emitting a signal
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61B 2090/397 electromagnetic other than visible, e.g. microwave
• CPC Class Codes: A61B 2090/3995 Multi-modality markers
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers
• CPC Class Codes: A61K 49/0002 General or multifunctional contrast agents, e.g. chelated agents
• CPC Class Codes: A61K 49/0447 Physical forms of mixtures of two different X-ray contrast-enhancing agents, containing at least one X-ray contrast-enhancing agent which is a halogenated organic compound
• CPC Class Codes: A61K 49/18 characterised by a special physical form, e.g. emulsions, microcapsules, liposomes
• CPC Class Codes: A61K 49/223 Microbubbles, hollow microspheres, free gas bubbles, gas microspheres
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• CPC Class Codes: A61M 31/005 for contrast media
• CPC Class Codes: G01R 33/4812 MR combined with X-ray or computed tomography [CT]
• CPC Class Codes: G01R 33/4814 MR combined with ultrasound
• CPC Class Codes: G01R 33/5601 involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: H01F 41/0253 : for manufacturing permanent magnets
• CPC Class Codes: Y10T 29/49075 : including permanent magnet or core
• CPC Class Codes: Y10T 29/49888 : Subsequently coating
• CPC Class Codes: Y10T 29/4998 : Combined manufacture including applying or shaping of fluent material
• CPC Class Codes: Y10T 29/49982 : Coating

Abstract

An implantable tissue marker incorporates a contrast agent sealed within a chamber in a container formed from a solid material. The contrast agent is selected to produce a change, such as an increase, in signal intensity under magnetic resonance imaging (MRI). An additional contrast agent may also be sealed within the chamber to provide visibility under another imaging modality, such as computed tomographic (CT) imaging or ultrasound imaging.

Claims

1. A tissue marker capable of being implanted in a living human or animal subject, the marker comprising:

a biocompatible polymer tube capsule defining at least one internal chamber; and

a sensing medium in the at least one internal chamber, wherein the sensing medium is configured to produce a detectable signal in a magnetic resonance (MR) imaging modality with the marker fully implanted in the subject, wherein the biocompatible polymer tube capsule includes a first magnetic susceptibility that is substantially equivalent to a second magnetic susceptibility of the sensing medium; and

a radioactive agent, included in the biocompatible polymer tube capsule.

2. The marker of claim 1, wherein the magnetic susceptibility of the biocompatible polymer tube capsule and the sensing medium are substantially equivalent to a magnetic susceptibility of tissue of the living human or animal subject.

3. The marker of claim 1, wherein the sensing medium includes a liquid contrast agent sealed within a chamber of the biocompatible polymer tube capsule.

4. The marker of claim 1, wherein the marker is configured to also be radiopaque so as to be visible on a radiographic imaging modality when implanted within tissue of the subject.

5. The marker of claim 1, wherein the sensing medium is configured to provide an increase in MR imaging signal intensity resulting in a brighter region of an MR image than surrounding tissue.

6. The marker of claim 1, wherein the first magnetic susceptibility is matched to the second magnetic susceptibility to provide a reduced T₂* artifact.

7. The marker of claim 1, wherein the biocompatible polymer tube capsule is sized for insertion via a biopsy cannula.

8. The marker of claim 1, wherein the first magnetic susceptibility and the second magnetic susceptibility are matched to a magnetic susceptibility of surrounding tissue to provide a reduction of T₂ darkening to render negligible a T₂* artifact on a resulting MR image.

9. The marker of claim 1, wherein the radioactive agent is located in the at least one internal chamber.

10. The marker of claim 1, wherein the capsule includes a tube and lids at respective ends of the tube.

11. The marker of claim 1, wherein the capsule includes:

a first portion including at least two openings; and

a second and third portion configured to be attached to the first portion at the at least two openings.

12. The marker of claim 1, wherein the marker is sized and shaped to fit within a lumen of a cannula configured to deliver the marker to a fully implanted location within the subject.

13. A medical method of using a tissue marker capable of being implanted in a living human or animal subject, the method comprising:

delivering a tissue marker into tissue of the subject, wherein the marker comprises a biocompatible polymer tube capsule defining at least one internal chamber; and

a sensing medium in the internal chamber, wherein the sensing medium is configured to produce a detectable signal in a magnetic resonance (MR) imaging modality with the marker fully implanted in the subject, wherein the biocompatible polymer tube capsule includes a first magnetic susceptibility that is substantially equivalent to a second magnetic susceptibility of the sensing medium; and

a radioactive agent, included in the biocompatible polymer tube capsule;

imaging the subject including the marker, the imaging including producing a detectable signal in a magnetic resonance (MR) imaging modality.

14. The method of claim 13, wherein delivering the marker includes delivering the marker via a lumen of a biopsy cannula.

15. A tissue marker capable of being implanted in a living human or animal subject, the marker comprising:

a biocompatible polymer tube capsule defining at least one internal chamber; and

a sensing medium in the at least one internal chamber, wherein the sensing medium is configured to produce a detectable signal in a magnetic resonance (MR) imaging modality with the marker fully implanted in the subject, wherein the first magnetic susceptibility of the biocompatible polymer tube capsule and the second magnetic susceptibility of the sensing medium are set close enough to the magnetic susceptibility of the surrounding tissue to render negligible a T₂* artifact on a resulting MR image; and

a radioactive agent, included in the biocompatible polymer tube capsule.

16. The marker of claim 15, wherein the biocompatible polymer tube capsule is sized for insertion via a biopsy cannula.

17. The marker of claim 15, wherein the marker is sized and shaped to fit within a lumen of a cannula configured to deliver the marker to a fully implanted location within the subject.

18. The marker of claim 15, wherein the radioactive agent is located in the at least one internal chamber.