Adult head-sized coil-based low-field MRI
An ultra-low field pre-pulse Magnetic Resonance Imaging (PMRI) system for a head includes RF coils defining a bore for head access, a pre-pulse coil outside the RF coils, and a coil assembly including a main magnetic field coil and gradient coils outside the pre-pulse coil. The PMRI system includes a first cylindrical shield concentric with the RF coils and made from conductive materials. The first cylindrical shield partially encloses the RF coils and inside the pre-pulse coil for shielding the RF coils from environmental electromagnetic disturbances.
1. An ultra-low field pre-pulse Magnetic Resonance Imaging (PMRI) system for a head, comprising:
annular RF coils defining a bore having an opening for access of the head;
a pre-pulse coil substantially surrounding the RF coils;
a coil assembly including a main magnetic field coil and a plurality of gradient coils surrounding the pre-pulse coil; and
a first cylindrical shield concentric with the RF coils, the first cylindrical shield partially surrounding the RF coils and being disposed inside the pre-pulse coil for shielding the RF coils from environmental electromagnetic disturbances, the first cylindrical shield made from conductive materials.
2. The PMRI system according to claim 1 , further comprising a second cylindrical shield concentric with the first cylindrical shield, partially surrounding the pre-pulse coil, and being disposed inside the coil, assembly.
3. The PMRI system according to claim 2 , further comprising a third cylindrical shield concentric with the first and second cylindrical shields and substantially surrounding the coil assembly.
4. The PMRI system according to claim 3 , wherein the third cylindrical shield includes a wall formed of spaced bars.
5. The PMRI system according to claim 3 , wherein the third cylindrical shield is made from ferromagnetic materials.
6. The PMRI system according to claim 1 , wherein an open end of the first cylindrical shield is flared for a larger child or adult with shoulders wider than the bore.
7. The PMRI system according to claim 1 , wherein the first cylindrical shield is passive.
8. The PMRI system according to claim 1 , wherein the first cylindrical shield is grounded.
9. The PMRI system according to claim 1 , wherein the first cylindrical shield is driven adaptively.
10. The PMRI system according to claim 1 , wherein the first cylindrical shield has an open end for the head access and a capped end away from the open end.
11. The PMRI system according to claim 1 , wherein the first cylindrical shield is made from aluminum or brass.