Cryogenically cooled superconductor rf head coil array and head-only magnetic resonance imaging (mri) system using same

Abstract

A cryogenically-cooled superconducting RF head-coil array which may be used in whole-body MRI scanners and/or in dedicated, head-only MRI systems. An RF head-coil array module may comprise a vacuum thermal isolation housing comprising a double wall hermetically sealed jacket that (i) encloses a hermetically sealed interior space under a vacuum condition, and (ii) substantially encloses an interior chamber region that is separate from the hermetically sealed interior space and is configured to be evacuated to a vacuum condition. A plurality of superconductor radiofrequency coils are disposed in the interior chamber region, and each radiofrequency coil is configured for at least one of generating and receiving a radiofrequency signal for at least one of magnetic resonance imaging and magnetic resonance spectroscopy. At least one thermal sink member may be disposed in the interior chamber region and in thermal contact with the superconductor radiofrequency coils. A port is configured for cryogenically cooling the thermal sink members.

1 . A superconducting radiofrequency coil array module configured for cryogenic cooling, comprising:
 a vacuum thermal isolation housing comprising a double wall hermetically sealed jacket that (i) encloses a hermetically sealed interior space under a vacuum condition, and (ii) substantially encloses an interior chamber region that is separate from the hermetically sealed interior space and is configured to be evacuated to a vacuum condition;   a plurality of superconductor radiofrequency coils disposed in said interior chamber region, each radiofrequency coil configured for at least one of generating and receiving a radiofrequency signal for at least one of magnetic resonance imaging and magnetic resonance spectroscopy;   at least one thermal sink member disposed in said interior chamber region and in thermal contact with the superconductor radiofrequency coils; and   a port configured for cryogenically cooling at least the thermal sink member.   
     
     
         2 . The module according to  claim 1 , wherein the port is coupled to a cryocooler that is thermally coupled to the at least one thermal sink member. 
     
     
         3 . The module according to  claim 2 , wherein the coupling of the cryocooler to the port provides for sealing said interior chamber region such that the interior chamber region is under a vacuum condition. 
     
     
         4 . The module according to  claim 1 , wherein said hermetically sealed jacket is sealedly joined to a chamber having an interior space that is coextensive with and is configured to be evacuated to substantially the same vacuum condition as said interior chamber region, wherein said port is provided in said chamber. 
     
     
         5 . The module according to  claim 4 , wherein said chamber is configured as a double walled chamber that encloses a hermetically sealed intra-wall cavity that is under vacuum. 
     
     
         6 . The module according to  claim 4 , wherein the port is coupled to a cryocooler that is thermally coupled to the at least one the thermal sink member. 
     
     
         7 . The module according to  claim 6 , wherein the coupling of the cryocooler to the port provides for sealing said interior chamber region such that the interior chamber region is under a vacuum condition. 
     
     
         8 . The module according to  claim 4 , wherein the chamber is a double walled stainless steel chamber. 
     
     
         9 . The module according to  claim 4 , wherein the hermetically sealed interior space is under a vacuum condition having a vacuum pressure in the range of about 10-6 to about 10-12 Torr, and the interior chamber region is under a vacuum condition having a vacuum pressure in the a range of about 10-2 to about 10-6 Torr. 
     
     
         10 . The module according to  claim 9 , wherein said chamber is configured as a double walled chamber that encloses a hermetically sealed intra-wall cavity that is under vacuum condition having a vacuum pressure in the range of about 10-6 to about 10-12 Torr. 
     
     
         11 . The module according to  claim 1 , wherein the hermetically sealed interior space is under a vacuum condition having a vacuum pressure in the range of about 10-6 to about 10-12 Torr, and the interior chamber region is under a vacuum condition having a vacuum pressure in the a range of about 10-2 to about 10-6 Torr. 
     
     
         12 . The module according to  claim 1 , wherein each radiofrequency coil is in direct thermal contact with a respective one of said thermal sink members that are each in direct thermal contact with another of said thermal sink members that is in thermal contact with said cryocooler. 
     
     
         13 . The module according to  claim 1 , wherein said radiofrequency coils comprise at least eight radiofrequency coils that are azimuthally displaced about a common longitudinal axis at a substantially common displacement along said longitudinal axis, and are configured for imaging a region surrounded by the radiofrequency coils. 
     
     
         14 . The module according to  claim 1 , wherein each of the radiofrequency coils is configured to receive and not transmit radiofrequency signals. 
     
     
         15 . The module according to  claim 1 , wherein the superconductor material comprises an HTS material. 
     
     
         16 . The module according to  claim 1 , wherein the vacuum thermal isolation housing and radiofrequency coils are dimensioned and configured for head imaging and not whole body imaging. 
     
     
         17 . The module according to  claim 16 , wherein said radiofrequency coils comprise at least eight radiofrequency coils that are azimuthally displaced about a common longitudinal axis at a substantially common displacement along said longitudinal axis, and are configured for imaging a region surrounded by the radiofrequency coils. 
     
     
         18 . The module according to  claim 1 , wherein the radiofrequency coil array module is dimensioned and configured for use in a head-only magnetic resonance imaging system that comprises a main electromagnet system comprising:
 a first and second set of high temperature superconductor coils which are configured to be coaxial relative to a common longitudinal axis;   wherein the first coil set includes at least two coils having an inner radius and disposed in a first region of a length along the common axis to cover a head and neck of a human body, and the second coil set includes at least one coil having an inner radius and disposed in a second region of a length along the common axis to cover a portion of a human torso, wherein the inner radius of the second coil set is greater than the inner radius of the first coil set; and   wherein the first and second coils are configured to provide a uniform magnetic field in the first region to provide for imaging a region of interest of the individual's head when positioned within the first region.