Nuclear magnetic resonance imaging apparatus having a magnetic structure that oscillates about an axis

• US 6,278,274 B1
• Filed: 08/12/1999
• Issued: 08/21/2001
• Est. Priority Date: 08/31/1998
• Status: Expired due to Term

• Current Assignee: Esaote SpA
• Original Assignee: Esaote SpA
• Inventors: Rezzonico, Fabio, Satragno, Luigi, Biglieri, Eugenio, Pugliese, Osvaldo
• Primary Examiner(s): Oda, Christine
• Assistant Examiner(s): Vargas, Dixomara
• Application Number:
  US09/372,609
• Time in Patent Office: 740 Days
• Field of Search: 324/318, 324/319, 324/309, 324/307, 324/320
• US Class Current: 324/318
• CPC Class Codes: G01R 33/3806 Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets

Abstract

Nuclear Magnetic Resonance imaging apparatus of the type for imaging specific parts of the body, the device including a magnetic structure (1), having a cavity (101) for accommodating the limb part to be examined, which may be accessed from the outside, and in which, or at least in one part of which (V) the necessary magnetic fields are generated. The magnetic structure (1) is supported in such a manner as to be able to oscillate (O) about a horizontal axis, which is parallel to the static magnetic field, whereas the axis of oscillation (O) is staggered with respect to the central axis, which is parallel thereto and passes through the cavity volume (V), wherein the static magnetic field has the characteristics required for valid imaging, to such an extent that the relevant volume (V) moves from an uppermost position to a lowermost position, the two extreme positions as well as those intervening therebetween being adjusted to the head and/or neck and/or upper limbs level in the standing and/or sitting positions of the patient and to the lower limbs level in the standing and/or sitting positions of the patient respectively.

Claims

1. A Nuclear Magnetic Resonance imaging apparatus of the type for imaging parts of the body, the apparatus comprising:

a magnetic structure having a cavity for accommodating a part of the body to be examined;

designed to generate in the cavity, or at least in a part thereof, magnetic and electromagnetic fields required for Nuclear Magnetic Resonance imaging;

the magnetic structure is mounted on a support in such a manner as to be movable at least in two directions;

the magnetic structure is supported in such a manner as to be able to oscillate about a horizontal axis of oscillation, parallel to the static magnetic field generated thereby, whereas the axis of oscillation is staggered with respect to a central axis of the cavity and which central axis is parallel to the axis of oscillation and passes through the cavity;

the static magnetic field has characteristics required for valid diagnostic imaging,

the cavity being movable between two extreme positions, that is, from an uppermost position to a lowermost position, the two extreme positions and those intervening therebetween being adjusted to the body part in the standing or sitting positions of the patient.

2. An apparatus as claimed in claim 1, wherein the axis of oscillation of the magnetic structure is eccentric to a median axis of the overall geometry thereof, whereas the magnetic structure has radial dimensions, with respect to the median axis thereof, parallel to the axis of oscillation, of {fraction (1/10)} to {fraction (4/10)} of the average height of an adult in his/her standing position.

3. An apparatus as claimed in claim 2, wherein the apparatus has a configuration in which the axis of oscillation of the magnetic structure is eccentric to the median axis of the overall geometry thereof, whereas the magnetic structure has radial dimensions, with respect to the median axis thereof, parallel to the axis of oscillation, of ⅛

to {fraction (4/8)} of the average height of an adult in his/her sitting position.

4. An apparatus as claimed in claim 1, wherein the position of the axis of oscillation of the magnetic structure with respect to the ground is generally higher than the greatest radial dimensions of the magnetic structure with respect to the ground.

5. An apparatus as claimed in claim 1, wherein an aperture for access to the imaging cavity of the magnetic structure is provided in such a position that at least a part thereof has a central axis perpendicular to the axis of oscillation, whereas in the two upper and lower positions, it is at least partly turned towards the patient, and in the perpendicular condition of said axis of the aperture, it is substantially turned downwards or upwards.

6. An apparatus as claimed in claim 1, wherein the magnetic structure has an annular shape, round, oval, non-round, rectangular, square, or polygonal shape or a combination of these shapes, either symmetrical or asymmetrical to one or more reference axes or points, which structure is supported in such a manner as to be able to oscillate with an eccentric axis radial to the axis of two apertures for accessing a through cavity, the axis of the apertures being perpendicular in the intermediate position and the upper and lower positions being rotationally symmetrical.

7. An apparatus as claimed in claim 1, wherein the magnetic structure has two opposite poles preferably circular and connected together by at least an axial member perpendicular to the poles and joint thereto at least at one peripheral point thereof.

8. An apparatus as claimed in claim 7, wherein the axial member has the shape of at least one column.

9. An apparatus as claimed in claim 8, characterized in that the two columns are grouped in the peripheral area of the two opposite poles in order to provide a wider access aperture.

10. An apparatus as claimed in claim 1, wherein the imaging cavity area in which the magnetic field of the structure to provide valid Nuclear Magnetic Resonance imaging, is located in the median region of the overall radial dimensions of the magnetic structure with reference to the median axis thereof, parallel to the axis of oscillation.

11. An apparatus as claimed in claim 1, wherein the magnetic structure has sides transverse to the open sides, the latter being transverse to the axis of oscillation, which have a circular or oval or substantially elliptical plan shape, the axis of oscillation being eccentric to the greater axis of the elliptical shape.

12. An apparatus as claimed in claim 1, wherein the height position of the axis of oscillation of the magnetic structure from the ground is variable.

13. An apparatus as claimed in claim 1, wherein the apparatus has a structure for supporting the magnetic structure comprising two opposite uprights whereto the respective sides of the magnetic structure are pivoted about the axis of oscillation, while it is possible to provide, alternatively or in combination, that the pivot points of the magnetic structure are supported in such a manner as to be able to move with respect to the uprights, or that the uprights are extensible and reducible or inclinable.

14. An apparatus as claimed in claim 1, wherein the pivot points of the magnetic structure that is, the axis of oscillation thereof, are movable at least along one further horizontal component.

15. An apparatus as claimed in claim 13, wherein the magnetic structure and the uprights are supported upon a wheeled freely movable cart.

16. An apparatus as claimed in claim 15, wherein the cart is of the idle type or provided with motor-driven, particularly electric, propulsion means.

17. An apparatus as claimed in claim 16, wherein the apertures for access to the imaging cavity or the axis of oscillation is parallel or transverse or perpendicular to the longitudinal axis of the cart, that is to the axis of the wheels.

18. An apparatus as claimed in claim 17, wherein the support uprights branch off from an end of the cart and are inclined or curved towards the opposite end, bearing the magnetic structure which projects over the area extending from the central zone to said opposite end of the cart.

19. An apparatus as claimed in claim 15, wherein the cart has one or more recesses on the sides associated to the aperture/s of the magnetic structure.

20. An apparatus as claimed in claim 1, wherein the static magnetic field generated by the magnetic structure is parallel to the axis of oscillation.

21. An apparatus as claimed in claim 1, wherein the uprights have ergonomic grip handles integrated therein or attached thereto.

22. An apparatus as claimed in claim 15, wherein abutment members or walls are fixed to the uprights or to the cart, for examining anatomic regions of limbs under stress conditions.

23. An apparatus as claimed in claim 1, wherein the dimensions of the magnetic structure in the direction of depth of the imaging cavity between the poles in order are to examine all the head, and/or the neck, and/or the length of an upper and/or lower limb up to the area connected to the trunk.

24. An apparatus as claimed in claim 1, wherein it has a console or control panel, which is at least oriented, but even moved away or separated from the structure or disjoined from the apparatus, being provided, in this case, with a connecting wire.

25. An apparatus as claimed in claim 15, wherein a cabinet containing the processing or displaying electric and electronic units is also accommodated on the cart.

26. An apparatus as claimed in claim 1, wherein the cabinet containing at least a part of the electric and electronic units is mounted on a separate cart, which can be joined to and disjoined from the cart bearing the magnetic structure with or without the console.

27. An apparatus as claimed in claim 7, wherein the axial member has the shape of at least two columns along the circumference of the poles.