摘要:
Black blood time to inversion (BBTI) tag-on and tag-off images acquired by magnetic resonance imaging (MRI) are analyzed to produce difference magnitude 3D images as a function of time (BBTI values) representing blood perfusion in a region of interest (ROI). Perfusion data of the ROI having values which are different for normal and abnormal myocardial tissues are displayed for plural slices of a 3D image and for plural BBTI values in a single display panel.
摘要:
Elicited MRI signals are processed into MR image data in conjunction (a) with use of an initial spatially-selective RF tag pulse (tag-on) and (b) without use of an initial spatially-selective NMR RF tag pulse (tag-off) in respectively corresponding data acquisition subsequences. Multi-dimensional tag-on and tag-off data acquisition subsequences are used for each of plural time-to-inversion (TI) intervals without using an injected contrast agent. Acquired image data sets are subtracted for each TI interval to produce difference values as a function of time representing blood perfusion for the ROI that differentiates between normal, ischemic and infarct tissues.
摘要:
Elicited MRI signals are processed into MR image data in conjunction (a) with use of an initial spatially-selective RF tag pulse (tag-on) and (b) without use of an initial spatially-selective NMR RF tag pulse (tag-off) in respectively corresponding data acquisition subsequences. Multi-dimensional tag-on and tag-off data acquisition subsequences are used for each of plural time-to-inversion (TI) intervals without using an injected contrast agent. Acquired image data sets are subtracted for each TI interval to produce difference values as a function of time representing blood perfusion for the ROI that differentiates between normal, ischemic and infarct tissues.
摘要:
A magnetic resonance imaging (MRI) system and method (a) acquires k-space data for a patient ROI over a predetermined band of RF frequencies using RF excitation pulses having respectively corresponding RF frequencies incrementally offset from a nuclear magnetic resonant (NMR) Larmor frequency for free nuclei thus causing chemical exchange saturation transfer (CEST) effects and to process such acquired data into Z-spectra data for voxels in the ROI; (b) analyzes the acquired Z-spectra data to provide spectral peak width data corresponding to T2/T2* tissue values in the ROI for macromolecules participating in magnetization transfer contrast (MTC) effects producing said Z-spectra data; and (c) stores and/or displays data representative of T2/T2* tissue values of the ROI which values are different for different tissues.
摘要:
A magnetic resonance imaging (MRI) system and method (a) acquires k-space data for a patient ROI over a predetermined band of RF frequencies using RF excitation pulses having respectively corresponding RF frequencies incrementally offset from a nuclear magnetic resonant (NMR) Larmor frequency for free nuclei over a predetermined range of different offset frequencies in which target macromolecule responses are expected and to process such acquired data into spectral data for voxels in the ROI; (b) analyzes the acquired spectral data to provide spectral peak width data corresponding to tissue values in the ROI for macromolecules participating in magnetization transfer contrast (MTC) effects producing said spectral data; and (c) stores and/or displays data representative of tissue values of the ROI which values are different for different tissues.
摘要:
A magnetic resonance imaging (MRI) system and method (a) acquires k-space data for a patient ROI over a predetermined band of RF frequencies using RF excitation pulses having respectively corresponding RF frequencies incrementally offset from a nuclear magnetic resonant (NMR) Larmor frequency for free nuclei thus causing chemical exchange saturation transfer (CEST) effects and to process such acquired data into Z-spectra data for voxels in the ROI; (b) analyzes the acquired Z-spectra data to provide spectral peak width data corresponding to T2/T2* tissue values in the ROI for macromolecules participating in magnetization transfer contrast (MTC) effects producing said Z-spectra data; and (c) stores and/or displays data representative of T2/T2* tissue values of the ROI which values are different for different tissues.
摘要:
MRI k-space data is acquired for a patient ROI during data acquisition sequences including a nuclear magnetic resonance (NMR) signal readout period using a late gadolinium enhanced (LGE) data acquisition sequence including at least one fat-specific RF NMR magnetization inversion pulse imposed (a) after a water-specific RF NMR magnetization inversion pulse timed to cause a substantial null in NMR magnetization of normal tissue protons near a center of the readout period and (b) before the readout period center, which fat-specific inversion pulse is also timed to cause a substantial null in NMR magnetization of fat tissue protons near the readout period center. The acquired MR image data is reconstructed into a contrast enhanced LGE image of tissues within the ROI but having substantially suppressed normal and fat components therein.
摘要:
A type of sintered Nd—Fe—B permanent magnet with high corrosion resistance is produced by dual alloy method. The method comprises the following steps: preparing the powders of master phase alloy and intergranular phase alloy respectively, mixing the powders, compacting the powders in magnetic field, sintering the compacted body at 1050˜1125° C., and annealing at 920-1020° C. and 500-650° C. successively.
摘要:
A type of sintered Nd—Fe—B permanent magnet with high intrinsic coercivity of about 30KOe or more is produced by dual alloy method. The method comprises the following steps: preparing the powders of master phase alloy and intergranular phase alloy respectively, mixing the powders, compacting the powders in magnetic field, sintering the compacted body at 1050˜1125° C. and annealing at 890-1000° C. and 500-650° C. successively. In the process of preparing the powder of intergranular phase alloy, the nano-powder additive selected from the group consisting of NiAl, TiC, SiC, AlN, TiN, ZrN and the combination thereof is used to modify the powder of intergranular phase alloy.
摘要:
A type of sintered Nd—Fe—B permanent magnet with high intrinsic coercivity of about 30KOe or more is produced by dual alloy method. The method comprises the following steps: preparing the powders of master phase alloy and intergranular phase alloy respectively, mixing the powders, compacting the powders in magnetic field, sintering the compacted body at 1050˜1125° C. and annealing at 890-1000° C. and 500-650° C. successively. In the process of preparing the powder of intergranular phase alloy, the nano-powder additive selected from the group consisting of NiAl, TiC, SiC, AlN, TiN, ZrN and the combination thereof is used to modify the powder of intergranular phase alloy.