Magnetic resonance imaging apparatus provided with a magnetic assembly
An imaging apparatus comprising: at least a first module comprising a trolley provided with a plate on one face of which rests a magnetic assembly intended to apply a main magnetic field in an analysis zone of a main housing of the magnetic assembly, the trolley additionally comprising two side walls supporting the plate via one of their edges, designated the upper edge; a second module of substantially parallelepipedal shape, supporting a set of electronic control elements, the console being, in particular, configured to be inserted between the side walls of the trolley; the console and the first module comprising means of identification, by the console, of the geometric and magnetic features of the magnetic assembly of the first module, the means of identification being integrated in connection means.
1 . A magnetic resonance imaging apparatus comprising:
at least one first module, each first module from the at least one first module comprising a trolley having a plate with an upper face, a magnetic assembly resting on the upper face, the magnetic assembly configured to impose a main magnetic field in an analysis zone of a main housing of the magnetic assembly, the trolley further comprising two side walls supporting the plate by an upper edge;
a second module including a substantially parallelepiped console supporting a set of electronic control elements of the imaging apparatus, the console configured to be inserted, by a sliding connection, between the two side walls of the trolley of each first module from the at least one first module; and
wherein the at least one first module and the second module comprise means for identifying, by the console, geometric and magnetic features of the magnetic assembly of the at least one first module, the means for identifying being integrated into connection means of the console and of the at least one first module.
2 . The imaging apparatus of claim 1 , wherein the magnetic assembly comprises:
a plurality of support plates, each support plate of the plurality having an annular section delimiting a support opening, the plurality of support plates being assembled together, by alignment means, along a main axis, so that the support openings, aligned along the main axis, delimit a main housing of generally cylindrical shape, each support plate of the plurality further comprising a first plurality of permanent magnets, housed in first housings provided in the annular section, according to at least one annular Halbach array around the main axis, a set of magnets of the first plurality of permanent magnets creating a primary magnetic field in an analysis zone of the main housing that has a first uniformity; and
a plurality of annular parts assembled coaxially with the annular section, and integral with the plurality of support plates, each annular part comprising a second plurality of magnets housed in second housings provided in each annular part, the plurality of annular parts being arranged so as to create a secondary magnetic field in the analysis zone so that a resultant main field of the primary magnetic field and of the secondary magnetic field in the analysis zone has a second improved uniformity with regard to the first uniformity.
3 . The imaging apparatus of claim 1 , wherein the magnetic assembly further comprises a radiofrequency coil and gradient coils arranged in the main housing and mechanically integral with the magnetic assembly.
4 . The imaging apparatus of claim 2 , wherein the magnetic assembly comprises a main part inserted between two secondary parts, the main part being formed of main support plates, and the two secondary parts being formed from secondary support plates, a first opening of the main support plates has a first diameter, while a second opening of the secondary support plates has a second diameter smaller than the first diameter.
5 . The imaging apparatus of claim 2 , wherein the support plates comprise a non-magnetic material.
6 . The imaging apparatus of claim 2 , wherein the alignment means comprises threaded rods at least substantially parallel to the main axis and rigidly connecting the support plates together.
7 . The imaging apparatus of claim 2 , wherein each support plate of the plurality comprises a first plate and a second plate assembled against one another by a contact face, each first housing comprising two cavities formed from the contact face of one and/or an other of the first plate and the second plate.
8 . The imaging apparatus of claim 2 , wherein the annular parts are held together with the plurality of support plates by threaded rods.
9 . The imaging apparatus of claim 2 , wherein the support plates of the plurality comprise inner or outer tabs having housings capable of housing one or several permanent magnets.
10 . The imaging apparatus of claim 2 , wherein the annular parts are arranged in the main housing.
11 . The imaging apparatus of claim 2 , wherein the annular parts are arranged externally to the main housing, each annular part being inserted between two support plates of the plurality of support plates.
12 . The imaging apparatus of claim 3 , wherein the radiofrequency coil and the gradient coils are removable.
13 . The imaging apparatus of claim 6 , wherein each support plate of the plurality is enclosed between two cover plates, the two cover plates being configured to retain the magnets of the first plurality of permanent magnets in the first housings of the support plates of the plurality of support plates.
14 . The imaging apparatus of claim 7 , wherein the alignment means comprise at least one rail provided with alignment notches, each alignment notch holding a support plate of the plurality of support plates, the alignment notches being configured to maintain a predetermined spacing into two adjacent support plates of the plurality of support plates.
15 . The imaging apparatus of claim 7 , wherein the alignment means comprises an alignment element provided with a base surmounted by a cradle forming a cylinder portion having grooves on an inner surface thereof, each of the support plates of the plurality of support plates being held in a respective groove of the grooves.
16 . The imaging apparatus of claim 5 , wherein the non-magnetic material comprises aluminum or a plastic material.
17 . The imaging apparatus of claim 13 , wherein each support plate of the plurality comprises an alignment opening so that the magnetic assembly comprises at least one alignment passage of square or rectangular cross-section formed by the alignment opening and that extends parallel to the main axis, the magnetic assembly further comprising at least one alignment tube passing through the at least one alignment passage, and having a shape corresponding to the cross-section of the at least one alignment passage, the at least one alignment tube being intended to fix the magnetic assembly to the trolley.
18 . The imaging apparatus of claim 15 , wherein each support plate of the plurality of support plates comprises an outer tongue that extends radially from the annular section and that is inserted into a cavity at a bottom of the groove holding the respective support plate of the plurality of support plates.
19 . The imaging apparatus of claim 16 , wherein the non-magnetic material comprises PMMA.
20 . The imaging apparatus of claim 13 , wherein the alignment means comprises nuts cooperating with the threaded rods.