Device construction and method facilitating magnetic resonance imaging of foreign objects in a body

• US 4,989,608 A
• Filed: 04/28/1989
• Issued: 02/05/1991
• Est. Priority Date: 07/02/1987
• Status: Expired due to Term

• Current Assignee: Adam V. Ratner
• Original Assignee: Medical Magnetics Incorporated 13435 Country Way Los Altos Hills CA
• Inventors: Ratner, Adam V.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Zele, John D.
• Application Number:
  US07/345,892
• Time in Patent Office: 648 Days
• Field of Search: 128/653, 128/654, 128/656, 128/658, 128/659, 128/653 A, 128/56 R, 604/280, 604/264, 600/12, 606/28
• US Class Current: 600/420
• CPC Class Codes: A61L 29/18 Materials at least partially X-ray or laser opaque
• CPC Class Codes: A61M 25/0127 Magnetic means; Magnetic markers
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography

Abstract

Device construction facilitating the visibility of a device when inserted into a body being subjected to magnetic resonance imaging having a member adapted to be inserted into the body. The member carries material exhibiting a characteristic under magnetic resonance imaging which differs substantially from that of the body so that the visibility of the member under magnetic resonance imaging is substantially enhanced.

Method for imaging foreign objects in a body having tissue by the use of magnetic resonance imaging and x-ray imaging. The method comprises the steps of causing the foreign object to carry at least one material causing the foreign object to exhibit a characteristic under magnetic resonance imaging which differs from the characteristic of the tissue of the body to enhance the visibility of the foreign object when positioned in the body and also to exhibit a characteristic under x-ray imaging. The foreign object is inserted into the body. The body is then subjected to magnetic and radiofrequency fields to create magnetic resonance in the body and in the foreign object. A magnetic resonance image of the foreign object in the body is then displayed. The body is also subjected to x-rays. An x-ray image of the foreign object in the body is then displayed.

Claims

1. A device which is specifically useful during magnetic resonance imaging of body tissue comprising:

a flexible member of resinous material adapted to be inserted in the body tissue, the flexible member having ferromagnetic particles embedded therein at a concentration of about 0.001% to about 10% by weight of the material wherein, under magnetic resonance imaging, the flexible member exhibits characteristics which differ substantially from characteristics of the body tissue so that the visibility of the flexible member under magnetic resonance imaging is substantially enhanced, resulting in the flexible member being distinguishable from adjacent tissue as a dark area in brighter tissues and as a bright area in darker tissues, said member being free of elements which tend to degrade the overall quality of magnetic resonance images of the body tissues.

2. A device as in claim 1 wherein said flexible member is a flexible tubular member.

3. A device as in claim 2 wherein the ferromagnetic particles extend throughout the entire material forming the tubular member.

4. A device as in claim 2 wherein the ferromagnetic particles are disposed in only a portion of the tubular member.

5. A device as in claim 2 wherein the ferromagnetic particles are disposed in a stripe extending longitudinally of the tubular member.

6. In combination, an apparatus for generating a magnetic resonance image of a body having tissue therein and a device adapted to be inserted into the body, said device comprising a flexible member of resinous material, the flexible member having ferromagnetic particles embedded therein of a concentration of about 0.001% to about 10% by weight of the material, wherein under magnetic resonance imaging, the flexible member exhibits characteristics which differ substantially from those of the body so that the visibility of the member under magnetic resonance imaging is substantially enhanced, resulting in the flexible member being distinguishable from adjacent tissue as a darker area in brighter tissue and as a bright area in dark tissue, said member being free of elements which tend to degrade the overall quality of magnetic resonance image of the body.

7. A device which is capable of being imaged using magnetic resonance imaging and x-ray imaging, of a body comprising a flexible member adapted to be inserted into the body, contrast means comprised of two different materials carried by the member exhibiting a characteristic under magnetic resonance imaging which differs substantially from that of the body so that the visibility of the member under magnetic resonance imaging is substantially enhanced, said member being free of elements which tend to degrade the overall quality of the magnetic resonance image of the body and contrast means carried by the member for making at a portion of the member visible on X-ray images.

8. A device as in claim 7 wherein said two materials are spaced apart from each other in the member.

9. A device as in claim 8 wherein said two materials are disposed longitudinally of the member.

10. A device as in claim 7 wherein at least one of the materials is disposed as a stripe extending longitudinally of the member.

11. A device as in claim 10 wherein at least one of the materials is disposed as a band extending circumferentially of the member.

12. A device as in claim 11 wherein said at least one material is disposed in a plurality of bands disposed longitudinally of the member.

13. A method for imaging a foreign object in a body having tissue by the use of magnetic resonance imaging and x-ray imaging, comprising:

incorporating two different materials in the foreign object which two different materials cause the foreign object to exhibit characteristics under x-ray and magnetic resonance imaging which differ from characteristics of the tissues of the body under x-ray and magnetic resonance imaging, keeping the foreign object free of elements which tend to degrade the overall quality of the magnetic resonance image and the x-ray image while still allowing display of the foreign object in magnetic resonance and x-ray images body; and

imaging the body using magnetic resonance imaging and x-ray imaging, inserting the foreign object into the

14. A method as in claim 13 wherein the step of introducing two different materials is performed so that the two different materials are spaced apart in the foreign object.

15. A method as in claim 14 further including the step of forming one of the two materials as a stripe extending longitudinally of the foreign object.

16. A method as in claim 14 further including the step of forming one of the materials so that it extends circumferentially of the foreign object.

17. A method as in claim 16 further includes the step of forming said one material in a plurality of spaced apart circumferential bands.

18. A method of rendering an implanted foreign object of resinous material distinguishable from adjacent tissue when using magnetic resonance imaging to create images of body tissue which images include an image of the foreign object therewith, the method comprising incorporating a distribution of ferromagnetic particles in the material of which the foreign object is configured at a concentration in the range of about 0.001% to about 10% by weight, using concentrations which are lower in the range if the object if relatively large, and using concentrations which are higher in the range if the object is relatively small so as to render the object distinguishable from adjacent tissue as a dark area in bright tissues and as a bright area in dark tissues.

19. A method as in claim 18, wherein the foreign object creates an imaging artifact which is larger than the foreign object to facilitate its detection and location during magnetic resonance imaging.

20. The method of claim 18, wherein the concentration is in the range of 0.01% to 2% by weight.

21. The method of claim 20, wherein the implanted foreign object is a flexible tube.