Ferromagnetic augmentation for magnetic resonance imaging

Abstract

In some aspects, a magnetic system for use in a low-field MRI system. The magnetic system comprises at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B0 field for the low-field MRI system, and at least one permanent magnet to produce a magnetic field to contribute to the B0 field.

What is claimed is: 
     
         1 . A magnetic resonance imaging system comprising:
 a B 0  magnet comprising at least one permanent magnet, the B 0  magnet configured to generate a magnetic field to contribute to a B 0  magnetic field;   a ferromagnetic yoke configured to capture and direct at least some of the magnetic field generated by the B 0  magnet to increase magnetic flux density within an imaging region of the magnetic resonance imaging system, wherein the ferromagnetic yoke provides a plurality of magnetic return paths distributed on opposing sides of the B 0  magnet; and   a cart comprising a plurality of wheels, the cart supporting the B 0  magnet and the ferromagnetic yoke.   
     
     
         2 . The magnetic resonance imaging system of  claim 1 , wherein the cart further comprises a handlebar. 
     
     
         3 . The magnetic resonance imaging system of  claim 1 , further having a surface for supporting a patient during imaging, wherein the cart also supports the surface. 
     
     
         4 . The magnetic resonance imaging system of  claim 1 , wherein the plurality of magnetic return paths comprise a plurality of ferromagnetic posts asymmetrically positioned on opposing sides of the B 0  magnet. 
     
     
         5 . The magnetic resonance imaging system of  claim 1 , wherein the plurality of magnetic return paths comprise a plurality of ferromagnetic posts symmetrically positioned on opposing sides of the B 0  magnet. 
     
     
         6 . The magnetic resonance imaging system of  claim 1 , wherein the B 0  magnet is a biplanar magnet. 
     
     
         7 . The magnetic resonance imaging system of  claim 6 , wherein the biplanar magnet is oriented vertically, such that a top magnet of the biplanar magnet is supported above a bottom magnet of the biplanar magnet. 
     
     
         8 . The magnetic resonance imaging system of  claim 1 , wherein the ferromagnetic yoke comprises at least one beveled corner. 
     
     
         9 . The magnetic resonance imaging system of  claim 1 , wherein the B 0  magnetic field is produced at a strength equal to or less than 0.2 T. 
     
     
         10 . The magnetic resonance imaging system of  claim 1 , wherein the B 0  magnetic field is produced at a strength equal to or less than 0.1 T. 
     
     
         11 . A magnetic resonance imaging system comprising:
 a B 0  magnet configured to generate a magnetic field to contribute to a B 0  magnetic field;   a ferromagnetic yoke configured to capture and direct at least some of the magnetic field generated by the B 0  magnet to increase magnetic flux density within an imaging region of the magnetic resonance imaging system, wherein the ferromagnetic yoke provides a plurality of magnetic return paths distributed on opposing sides of the B 0  magnet;   a surface for supporting a patient during imaging; and   a cart supporting the B 0  magnet, the ferromagnetic yoke, and the surface, the cart comprising a plurality of wheels.   
     
     
         12 . The magnetic resonance imaging system of  claim 11 , wherein the B 0  magnet is a biplanar magnet. 
     
     
         13 . The magnetic resonance imaging system of  claim 12 , wherein the biplanar magnet is oriented vertically, such that a top magnet of the biplanar magnet is supported above a bottom magnet of the biplanar magnet. 
     
     
         14 . The magnetic resonance imaging system of  claim 11 , wherein the ferromagnetic yoke comprises at least one beveled corner. 
     
     
         15 . The magnetic resonance imaging system of  claim 11 , wherein the cart further comprises a handlebar. 
     
     
         16 . A magnetic resonance imaging system comprising:
 a biplanar B 0  magnet comprising at least one permanent magnet, the B 0  magnet configured to generate a magnetic field to contribute to a B 0  magnetic field;   a ferromagnetic yoke configured to capture and direct at least some of the magnetic field generated by the B 0  magnet to increase magnetic flux density within an imaging region of the magnetic resonance imaging system, wherein the ferromagnetic yoke provides a plurality of magnetic return paths distributed on opposing sides of the B 0  magnet;   a cart supporting the B 0  magnet and the ferromagnetic yoke, the cart comprising a plurality of wheels.   
     
     
         17 . The magnetic resonance imaging system of  claim 16 , wherein the biplanar magnet is oriented vertically, such that a top magnet of the biplanar magnet is supported above a bottom magnet of the biplanar magnet. 
     
     
         18 . The magnetic resonance imaging system of  claim 16 , wherein the ferromagnetic yoke comprises at least one beveled corner. 
     
     
         19 . The magnetic resonance imaging system of  claim 16 , wherein the cart further comprises a handlebar. 
     
     
         20 . The magnetic resonance imaging system of  claim 16 , wherein the B 0  magnetic field is produced at a strength equal to or less than 0.2 T.