摘要:
A method for generating a magnetic resonance image includes acquiring a first k-space data set from each of a plurality of RF coils. The first k-space data set includes calibration data and randomly undersampled data. For each RF coil, a fully randomly sampled k-space data set is generated by removing a portion of the calibration data. A compressed sensing reconstruction technique is applied to the fully randomly sampled k-space data set to generate an aliased image, which is used to generate a uniformly undersampled k-space data set. A second k-space data set is generated by inserting the portion of the calibration data and a parallel imaging reconstruction technique is applied to the second k-space data set to synthesize unacquired data. The second k-space data set and the synthesized data are combined to generate a complete k-space data set for the RF coil.
摘要:
A CT system includes a gantry, an x-ray source, a detector, and a grating collimator that includes alternating first and second materials. The system includes a controller configured to emit a first beam of x-rays from a first focal spot and to a first detector pixel, wherein the first beam of x-rays passes along a ray and through one of the first materials of the grating collimator, and subsequently emit a second beam of x-rays from a second focal spot and to the first detector pixel, wherein the second beam of x-rays passes substantially along the ray and through one of the second materials of the grating collimator. The system includes a computer programmed to generate first and second kVp image datasets using data acquired from the first beam and second beams of x-rays, and reconstruct a basis material image of the object.
摘要:
A CT system includes a gantry, an x-ray source, a detector, and a grating collimator that includes alternating first and second materials. The system includes a controller configured to emit a first beam of x-rays from a first focal spot and to a first detector pixel, wherein the first beam of x-rays passes along a ray and through one of the first materials of the grating collimator, and subsequently emit a second beam of x-rays from a second focal spot and to the first detector pixel, wherein the second beam of x-rays passes substantially along the ray and through one of the second materials of the grating collimator. The system includes a computer programmed to generate first and second kVp image datasets using data acquired from the first beam and second beams of x-rays, and reconstruct a basis material image of the object.
摘要:
Methods and systems for correlated noise suppression are presented. The present correlated noise suppression technique estimates a correlation direction between noise values in a first and a second MD image corresponding to a first and a second basis material, respectively. The two MD images are diffused using the estimated correlation direction to generate a first and a second diffused image. Further, first and second noise masks are generated by subtracting the diffused image from the corresponding MD image. Edges in the first and the second MD images are processed with the first and second noise masks, respectively to generate a final first noise mask and a final second noise mask. The first MD image is then processed with the final second noise mask to generate a final first MD image and the second MD image is processed with the final first noise mask to generate a final second MD image.
摘要:
An apparatus and method include a computer programmed to implement a scan sequence configured to elicit scan data, wherein the scan sequence comprises an echo planar imaging (EPI) sequence configured to elicit the image data and to acquire the scan data. The computer is also programmed to manipulate the scan data to determine a first plurality of phase errors in the image data responsible for a Nyquist ghost, wherein the manipulated scan data is free of navigator echo data, remove the first plurality of phase errors from the image data, and reconstruct an image based on the image data having the first plurality of phase errors removed therefrom.
摘要:
A particle having a size of from about 50 to about 1,000 μm comprising a low-shear exfoliable nanoclay, the nanoclay having a primary particle size of from about 10 to about 300 nm. The invention also includes detergents comprising the particle and a process for making the particle.
摘要:
A method of cleaning a soiled load in an automatic dishwasher comprising the step of contacting the load with a phosphate free wash liquor comprising exfoliated nanoclay, the liquor having a pH of from about 9 to about 12 and an ionic strength of from about 0.001 to about 0.02 moles/l.
摘要:
A system and method are provided for designing RF pulses for multi-channel and/or multi-dimensional spatially-selective applications using a linear approximation. Embodiments of the system and method may use a generalized linear-class large tip angle approximation to design RF pulses for multi-channel and parallel transmission. Further, some of these approximations allow for the design of arbitrarily large flip angles, irregularly-shaped flip angle profiles, or arbitrary initial magnetization values. Embodiments of the system and method may also provide for the design of k-space trajectories which aid in maintaining assumptions of the various linear class approximations.
摘要:
A system and method are provided for designing RF pulses which have improved magnetization profiles. By utilizing an optimal control approach as an alternative to, or in combination with, non-iterative approximations, RF pulses generated by the system and method described herein will exhibit less deviation from that of “ideal” Bloch solutions. Consequently, the magnetization profiles produced by the RF pulses generated by the system and method described herein will be closer to the desired profiles. In addition, limitations of non-iterative approximations, such as maximum tip angle limits and linearity constraints, can be avoided.
摘要:
An apparatus and method include a computer programmed to implement a scan sequence configured to elicit scan data, wherein the scan sequence comprises an echo planar imaging (EPI) sequence configured to elicit the image data and to acquire the scan data. The computer is also programmed to manipulate the scan data to determine a first plurality of phase errors in the image data responsible for a Nyquist ghost, wherein the manipulated scan data is free of navigator echo data, remove the first plurality of phase errors from the image data, and reconstruct an image based on the image data having the first plurality of phase errors removed therefrom.