Abstract: A router (60), for use with magnetic resonance systems (10), selectively routes unique excitation signals, generated by a multi-channel radio-frequency (RF) amplifier, over transmission lines (Tx) to any one of a plurality of connection panels (66) which each accepts at least one RF coil assembly having multiple coil elements (20). Each connection panel (66) includes transceiver ports (68) for connecting at least one conductor (22,24) of the coil elements (20) to a corresponding transceiver channel (T/R). The router (60) selectively routes magnetic resonance signals received by the conductors (22,24) from the transceiver channels (T/R) to a multi-channel RF receiver (41). The coin elements may carry sine-mode currents or uniform currents.

Abstract: A hybrid imaging system includes a magnetic resonance scanner and a second modality imaging system disposed in the same radio frequency isolation space. The second modality imaging system includes radiation detectors configured to detect at least one of high energy particles and high energy photons. In some embodiments a retractable radio frequency screen is selectively extendible into a gap between the magnetic resonance scanner and the second modality imaging system. In some embodiments shim coils are disposed with the magnetic resonance scanner and are configured to compensate for distortion of the static magnetic field of the magnetic resonance scanner produced by proximity of the second modality imaging system.

Abstract: In preparation for acquiring PET image data, subject motion models are built based on physiologic signal monitoring and MR data is collected and used for improved PET imaging. The physiologic signal monitoring is also used during PET imaging, and the acquired MR data is used for prospective or retrospective gating of the PET image acquisition, or in the PET reconstruction for improved correction/imaging.

Abstract: An imaging method comprises: acquiring magnetic resonance data of a subject using a magnetic resonance component (30, 30?) disposed with the subject; acquiring nuclear imaging data of the subject with the magnetic resonance component disposed with the subject; determining a position of the magnetic resonance component respective to a frame of reference of the nuclear imaging data; and reconstructing the nuclear imaging data (60) to generate a nuclear image (62) of at least a portion of the subject. The reconstructing includes adjusting at least one of the nuclear imaging data and the nuclear image based on a density map (46) of the magnetic resonance component and the determined position of the magnetic resonance component respective to the frame of reference of the nuclear imaging data to correct the nuclear image for radiation absorption by the magnetic resonance component.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: When correcting for attenuation in a positron emission tomography (PET) image, a magnetic resonance (MR) image (24) of a subject is generated with spectroscopic data (38) describing the chemical composition of one or more of the voxels in the MR image. A table lookup is performed to identify a tissue type for each voxel based on the MR image data and spectral composition data, and an attenuation value is assigned to each voxel based on its tissue type to generate an MR attenuation correction (MRAC) map (30). The MRAC map (30) is used during reconstruction of the nuclear image (37) to correct for attenuation therein. Additionally, attenuation due to MR coils and other accessories that remain in a nuclear imager field of view during a combined MR/nuclear scan is corrected using pre-generated attenuation correction maps that are applied to a nuclear image after executing an MR scan to identify anatomical landmarks, which are used to align the pre-generated attenuation correction maps to the patient.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: An imaging system includes positron emission tomography (PET) detectors (30) shrouded by broadband galvanic isolation (99) and coincidence detection electronics (50, 50ob), or other radiation detectors. A magnetic resonance scanner includes a main magnet (12, 14) and magnetic field gradient assembly (20, 20?, 22, 24) configured to acquire imaging data from a magnetic resonance examination region at least partially overlapping the examination region surrounded by the PET detectors. A radio frequency coil (80, 100) has plurality of conductors (66, 166) and a radio frequency screen (88, 188, 188EB, 188F) substantially surrounding the conductors to shield the coil at the magnetic resonance frequency. The radiation detectors are outside of the radio frequency screen. Magnetic resonance-compatible radiation collimators or shielding (60, 62) containing an electrically non-conductive and non-ferromagnetic heavy atom oxide material are disposed with the radiation detectors.

Abstract: A hybrid imaging system and a patient bed for same are disclosed. The hybrid imaging system includes a magnetic resonance scanner and a second modality imaging system spaced apart from the magnetic resonance scanner by a gap. In some embodiments, the gap is less than seven meters. The patient bed is disposed at least partially in the gap between the magnetic resonance scanner and the second modality imaging system, and includes a linearly translatable patient support pallet aligned to be selectively moved into an examination region of the magnetic resonance scanner for magnetic resonance imaging and into an examination region of the second modality imaging system for second modality imaging. In some embodiments, a linear translation range of the linearly translatable pallet is less than five times a length of the patient support pallet along the direction of linear translation.

Abstract: A magnetic resonance coil comprises a first set of coil elements (54, 56, 80) operatively connectable with a transmit channel (66, 74) to couple with a transmit region of sensitivity for a selected load at a magnetic field strength greater than 3 Tesla, and a second set of coil elements (52, 54, 82) operatively connectable with a receive channel (66, 74) to couple with a receive region of sensitivity for the selected load at the magnetic field strength greater than 3 Tesla. The first set of coil elements is arranged proximate to but not surrounding the transmit region of sensitivity, and the second set of coil elements is arranged proximate to but not surrounding the receive region of sensitivity. The first set of coil elements and the second set of coil elements having at least one coil element (52, 56) not in common.

Abstract: A router (60), for use with magnetic resonance systems (10), selectively routes unique excitation signals, generated by a multi-channel radio-frequency (RF) amplifier, over transmission lines (Tx) to any one of a plurality of connection panels (66) which each accepts at least one RF coil assembly having multiple coil elements (20). Each connection panel (66) includes transceiver ports (68) for connecting at least one conductor (22,24) of the coil elements (20) to a corresponding transceiver channel (T/R). The router (60) selectively routes magnetic resonance signals received by the conductors (22,24) from the transceiver channels (T/R) to a multi-channel RF receiver (41). The coin elements may carry sine-mode currents or uniform currents.

Abstract: A radio frequency coil assembly includes an annular conductor (20, 22, 120) configured to support a sinusoidal electrical current distribution at a magnetic resonance frequency, and a radio frequency shield (30, 32, 34, 52, 60, 61, 130) shielding the annular conductor in at least one direction, the radio frequency shield including at least one of (i) a cylindrical shield portion (30, 60, 61, 130) surrounding a perimeter of the annular conductor, and (ii) a planar shield portion (32, 34, 52) arranged generally parallel with the annular conductor. In a magnetic resonance scanner embodiment, a magnet (10) generates a static magnetic field (B0), a magnetic field gradient system (14) is configured to superimpose selected magnetic field gradients on the static magnetic field, and said radio frequency coil assembly is arranged with the annular conductor generally transverse to the static magnetic field (B0).

Abstract: In a hybrid PET-MR system, PET detector elements (30) are added in the bore (14), in close proximity to the gradient coils (16). Fluid coolant is supplied to transfer heat from the PET detector elements (30). Thermal insulation (80) insulates the fluid coolant and the PET detector elements (30) from the gradient coils (16). In some embodiments, a first coolant path (90) is in thermal communication with the electronics, a second coolant path (92) is in thermal communication with the light detectors, and a thermal barrier (94, 96) is arranged between the first and second coolant paths such that the first and second coolant paths can be at different temperatures (Te, Td). In some embodiments a sealed heat pipe (110) is in thermal communication with a heat sink such that working fluid in the heat pipe undergoes vaporization/condensation cycling to transfer heat from the detector elements to the heat sink.

Abstract: A generally cylindrical set of coil windings (10, 30, 80) includes primary coil windings (12, 32, 82) and shield coil windings (14, 34, 84) at a larger radial position than the primary coil windings, and an arcuate or annular central gap (16, 36, 86) that is free of coil windings, has an axial extent (W) of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors (24, 44, 94) disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet (62, 64) is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors (66) is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: A radio frequency coil comprises an annular conductor or parallel annular conductors (22, 22c, 22d) configured to support: (i) a uniform electrical current distribution generating a first B1 field (B1,uniform) at a first magnetic resonance frequency directed out of a plane of the annular conductor or conductors; and (ii) a sinusoidal electrical current distribution generating a second B1 field (B1,sine) at a second magnetic resonance frequency directed parallel with the plane of the annular conductor or conductors. A magnetic resonance scanner comprises: a magnet (10) generating a static magnetic field (B0); a magnetic field gradient system (14) configured to superimpose selected magnetic field gradients on the static magnetic field; and said radio frequency coil including said annular conductor or parallel annular conductors (22, 22c, 22d).

Abstract: A positron emission tomography (PET) detector ring comprising: a radiation detector ring comprising scintillators (74) viewed by photomultiplier tubes (72); and a magnetic field shielding enclosure (83, 84) surrounding sides and a back side of the annular radiation detector ring so as to shield the photomultiplier tubes of the radiation detector ring. Secondary magnetic field shielding (76?) may also be provided, comprising a ferromagnetic material having higher magnetic permeability and lower magnetic saturation characteristics as compared with the magnetic field shielding enclosure, the second magnetic field shielding also arranged to shield the photomultiplier tubes of the radiation detector ring. The secondary magnetic field shielding may comprise a mu-metal.

Abstract: Hybrid circuitry (40, 40?, 40?) for operatively coupling a radio frequency drive signal (70) with a quadrature coil (30) is configurable in one of at least two coil modes of a group consisting of: (i) a linear I channel mode in which an I channel input port (42) is driven without driving a Q channel input port (44); (ii) a linear Q channel mode in which the Q channel input port is driven without driving the I channel input port; (iii) a quadrature mode in which both the I and Q channel input ports are driven with a selected positive phase difference; and (iv) an anti quadrature mode in which both the I and Q channel input ports are driven with a selected negative phase difference. A temporal sequence of the at least two coil modes may be determined and employed to compensate for B1 inhomogeneity.

Abstract: When correcting for attenuation in a positron emission tomography (PET) image, a magnetic resonance (MR) image (24) of a subject is generated with spectroscopic data (38) describing the chemical composition of one or more of the voxels in the MR image. A table lookup is performed to identify a tissue type for each voxel based on the MR image data and spectral composition data, and an attenuation value is assigned to each voxel based on its tissue type to generate an MR attenuation correction (MRAC) map (30). The MRAC map (30) is used during reconstruction of the nuclear image (37) to correct for attenuation therein. Additionally, attenuation due to MR coils and other accessories that remain in a nuclear imager field of view during a combined MR/nuclear scan is corrected using pre-generated attenuation correction maps that are applied to a nuclear image after executing an MR scan to identify anatomical landmarks, which are used to align the pre-generated attenuation correction maps to the patient.