Abstract: Methods, computing devices, and MRI systems that reduce artifacts produced by Maxwell gradient terms in TSE imaging using non-rectilinear trajectories are disclosed. With this technology, a RF excitation pulse is generated to produce transverse magnetization that generates a NMR signal and a series of RF refocusing pulses to produce a corresponding series of NMR spin-echo signals. An original encoding gradient waveform comprising a non-rectilinear trajectory is modified by adjusting a portion of the original encoding gradient waveform or introducing a zero zeroth-moment waveform segment at end(s) of the original encoding gradient waveform. During an interval adjacent to each of the series of RF refocusing pulses a first gradient pulse is generated. At least one of the first gradient pulses is generated according to the modified gradient waveform. An image is constructed from generated digitized samples of the NMR spin-echo signals obtained.

Abstract: Methods, computing devices, and MRI systems that reduce artifacts produced by Maxwell gradient terms in TSE imaging using non-rectilinear trajectories are disclosed. With this technology, a RF excitation pulse is generated to produce transverse magnetization that generates a NMR signal and a series of RF refocusing pulses to produce a corresponding series of NMR spin-echo signals. An original encoding gradient waveform comprising a non-rectilinear trajectory is modified by adjusting a portion of the original encoding gradient waveform or introducing a zero zeroth-moment waveform segment at end(s) of the original encoding gradient waveform. During an interval adjacent to each of the series of RF refocusing pulses a first gradient pulse is generated. At least one of the first gradient pulses is generated according to the modified gradient waveform. An image is constructed from generated digitized samples of the NMR spin-echo signals obtained.

Abstract: A method for phase correction in proton resonance frequency (PRF) thermometry application includes acquiring a series of magnetic resonance (MR) images comprising a first MR image and plurality of subsequent MR images depicting an anatomical area of interest. The MR images are acquired while tissue in the anatomical area of interest is undergoing a temperature change. Each subsequent MR image is registered to the first MR image to yield a plurality of registered images. A plurality of basis images are computed from the registered images using Principal Component Analysis (PCA). The basis images are used to remove motion-related phase changes from a second series of MR images, thereby yielding a motion corrected second series of MR images. One or more temperature difference maps are generated that depict a relative temperature change for the tissue in the anatomical area of interest based on the motion corrected second series.

Abstract: A method for decomposing noise into white and spatially correlated components during MR thermometry imaging includes acquiring a series of MR images of an anatomical object and generating a series of temperature difference maps of the anatomical object. The method further includes receiving a selection of a region of interest (ROI) within the temperature difference map and estimating total noise variance values depicting total noise variance in the temperature difference map. Each total noise variance value is determined using a random sampling of a pre-determined number of voxels from the ROI. A white noise component and a spatially correlated noise component of the total noise variance providing a best fit to the total noise variance values for all of the random samplings are identified. The white noise component and the spatially correlated noise component are displayed on a user interface.

Abstract: A gradient system characterization function (e.g., a gradient system transfer function) may be developed by measuring a behavior of the MR device at a target temperature and developing at least one gradient system characterization function for a gradient coil of a magnetic resonance (MR) device at the target temperature based on the measured behavior. A patient may be subsequently imaged by the MR device, wherein the imaging process comprises measuring a temperature of a gradient coil, determining a gradient system characterization function at the measured temperature, calculating a pre-emphasized gradient of the gradient coil, and imaging the patient using the pre-emphasized magnetic field component.

Abstract: A method for decomposing noise into white and spatially correlated components during MR thermometry imaging includes acquiring a series of MR images of an anatomical object and generating a series of temperature difference maps of the anatomical object. The method further includes receiving a selection of a region of interest (ROI) within the temperature difference map and estimating total noise variance values depicting total noise variance in the temperature difference map. Each total noise variance value is determined using a random sampling of a pre-determined number of voxels from the ROI. A white noise component and a spatially correlated noise component of the total noise variance providing a best fit to the total noise variance values for all of the random samplings are identified. The white noise component and the spatially correlated noise component are displayed on a user interface.

Abstract: A method for phase correction in proton resonance frequency (PRF) thermometry application includes acquiring a series of magnetic resonance (MR) images comprising a first MR image and plurality of subsequent MR images depicting an anatomical area of interest. The MR images are acquired while tissue in the anatomical area of interest is undergoing a temperature change. Each subsequent MR image is registered to the first MR image to yield a plurality of registered images. A plurality of basis images are computed from the registered images using Principal Component Analysis (PCA). The basis images are used to remove motion-related phase changes from a second series of MR images, thereby yielding a motion corrected second series of MR images. One or more temperature difference maps are generated that depict a relative temperature change for the tissue in the anatomical area of interest based on the motion corrected second series.

Abstract: The disclosure relates to methods, devices, and systems for developing gradient system characterization functions and imaging a patient using pre-emphasized magnetic field components in a magnetic resonance (MR) device, wherein the processes allow for a reduction in a number of artifacts when reconstructing the magnetic resonance image. The gradient system characterization function (e.g., a gradient system transfer function) may be developed by measuring a behavior of the MR device at a target temperature and developing at least one gradient system characterization function for a gradient coil of the MR device at the target temperature based on the measured behavior.