1. A magnetic resonance imaging method comprising the steps of
acquisition of sub-sampled magnetic resonance signals with a system of receiver antennae
the system of receiver antennae having a spatial sensitivity profile
reconstruction of a magnetic resonance image on the basis of
the sub-sampled magnetic resonance signals
the spatial sensitivity profile and
a priori image information
optimization of the reconstruction with respect to a pre-selected aspect of distribution of sampled data included in the sub-sampled magnetic resonance signals over the reconstructed magnetic resonance image,
wherein
said a priori information is taken into account as a constraint in said optimization.
2. A magnetic resonance imaging method as claimed in claim 1, wherein
an explorative scan for the acquisition of explorative magnetic resonance signals precedes the acquisition of the sub-sampled magnetic resonance signals and
the a priori information is obtained by the explorative acquisition.
3. A magnetic resonance imaging method as claimed in claim 2, wherein the spatial sensitivity profile of the system of receiver antennae is derived from the explorative scan.
4. A magnetic resonance imaging method as claimed in claim 2, wherein
a main receiver coil and several surface coils are employed for receiving magnetic resonance signals,
in the explorative scan
explorative magnetic resonance signals are acquired with the main receiver coil
explorative magnetic resonance signals are acquired with the surface coils, notably the acquisition from the surface coils being interleaved with the acquisition from the surface coils, and
the spatial sensitivity profile is computed from the explorative magnetic resonance signals acquired with the main receiver coil and magnetic resonance signals acquired with the surface coils.
5. A magnetic resonance imaging method as claimed in claim 4, wherein an explorative magnetic resonance image is reconstructed from the magnetic resonance signals acquired in the explorative scan.
6. A magnetic resonance imaging method as claimed in claim 5, wherein
extended magnetic resonance signals are interpolated from the magnetic resonance signals acquired with the main receiver coil and
the explorative magnetic resonance image is reconstructed from the extended magnetic resonance signals.
7. A magnetic resonance imaging system arranged to
acquire sub-sampled magnetic resonance signals with a system of receiver antennae
the system of receiver antennae having a spatial sensitivity profile
reconstruct a magnetic resonance image on the basis of
the sub-sampled magnetic resonance signals
the spatial sensitivity profile and
a priori image information
optimize the reconstruction with respect to a pre-selected aspect of distribution of sampled data included in the sub-sampled magnetic resonance signals over the reconstructed magnetic resonance image,
wherein
said a priori information is taken into account as a constraint in said optimization.
8. A computer program comprising instructions to
acquire sub-sampled magnetic resonance signals with a system of receiver antennae
the system of receiver antennae having a spatial sensitivity profile
reconstruct a magnetic resonance image on the basis of
the sub-sampled magnetic resonance signals
the spatial sensitivity profile and
a priori image information
optimize the reconstruction with respect to a pre-selected aspect of distribution of sampled data included in the sub-sampled magnetic resonance signals over the reconstructed magnetic resonance image,
wherein
said a priori information is taken into account as a constraint in said optimization.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A spinal stabilization system comprising:
a screw comprising a post, a threaded shank extending distally from the post, and a socket;
a torsion shaft comprising:
a distal section configured to be received within the socket;
a body comprising at least one cut; and
a proximal section comprising an externally-threaded portion and a tool-receiving recess;
a relief screw comprising a body having an externally-threaded portion, a proximal end having a tool-receiving recess, and a bore extending longitudinally therethrough, wherein the bore comprises an internally-threaded section configured to mate with the externally-threaded section of the torsion shaft; and
a compression nut comprising a proximal end having a tool-receiving recess, a body, and a bore extending longitudinally therethrough, wherein the bore comprises an internally-threaded portion configured to mate with the externally-threaded body of the relief screw.
2. The spinal stabilization system of claim 1, wherein at least a portion of the socket has a hexagonal lateral cross-section.
3. The spinal stabilization system of claim 1, wherein the post comprises a cylindrical outer surface.
4. The spinal stabilization system of claim 1, wherein the distal section of the torsion shaft comprises a lateral cross-section that is larger than a lateral cross-section of the body of the torsion shaft.
5. The spinal stabilization system of claim 1, wherein the distal section of the torsion shaft comprises a hexagonal lateral cross-section.
6. The spinal stabilization system of claim 1, wherein the body of the torsion shaft is cylindrical.
7. The spinal stabilization system of claim 1, wherein the body of the torsion shaft comprises a helical cut that extends along a length of the body.
8. The spinal stabilization system of claim 1, wherein the body of the torsion shaft is configured to flex under pressure from one or more vertebrae.
9. The spinal stabilization system of claim 1, wherein the body of the relief screw comprises external threading along its length.
10. The spinal stabilization system of claim 1, wherein the proximal end of the compression nut has an outer diameter that is greater than an outer diameter of the body of the compression nut.
11. The spinal stabilization system of claim 1, wherein the body of the compression nut has a constant outer diameter.
12. The spinal stabilization system of claim 1, wherein each tool-receiving recess has a hexagonal cross-section.
13. A spinal stabilization system comprising:
a fastener member comprising a head, a threaded body extending longitudinally from the head, and a socket;
a torsion member comprising:
a distal section configured to be received within the socket,
a flexible body, and
a proximal section comprising an externally-threaded portion and a tool-receiving recess;
a relief member comprising a bore extending longitudinally therethrough, a body comprising external threading, and a proximal end having a tool-receiving recess, wherein the bore comprises an internally-threaded portion configured to mate with the externally-threaded portion of the torsion member; and
a compression member comprising a proximal end having a tool-receiving recess and a bore extending longitudinally therethrough, wherein the bore comprises an internally-threaded portion configured to mate with the external threading of the relief member.
14. The spinal stabilization system of claim 13, wherein the socket extends through the head of the fastener member and into at least a portion of the threaded body.
15. The spinal stabilization system of claim 14, wherein the socket has a circular transverse cross section in the head and a hexagonal transverse cross section in the threaded body.
16. The spinal stabilization system of claim 13, wherein the flexible body of the torsion member comprises at least one cut.
17. An assembled spinal stabilization system comprising:
a fastener member comprising a head, a threaded body extending longitudinally from the head, and a socket;
a torsion member comprising a distal section, a flexible body, and a proximal section comprising an externally-threaded segment and a tool-receiving recess, wherein at least the distal section is disposed within the socket of the fastener member;
a relief member comprising a body comprising external threading and a bore extending longitudinally therethrough, wherein the bore comprises a proximal end having a tool-receiving recess and an internally-threaded portion engaged with the externally-threaded portion of the torsion member, and
a compression member comprising a bore extending longitudinally therethrough and a proximal end having a tool-receiving recess, wherein the bore comprises a threaded portion engaged with the external threading of the relief member.
18. The spinal stabilization system of claim 17, wherein the distal section of the torsion member comprises a width that is larger than a width of the body of the torsion member.
19. The spinal stabilization system of claim 17, wherein all tool-receiving recesses are accessible by a driver.
20. The spinal stabilization system of claim 17, wherein the system has a variable length.