Abstract: A computer-implemented method of processing complex magnetic resonance (MR) images is provided. The method includes receiving a pair of corrupted complex data and pristine complex images. The method also includes training a neural network model using the pair by inputting the corrupted complex data to the neural network model, setting the pristine complex images as target outputs, and processing the corrupted complex data using the neural network model to derive output complex images of the corrupted complex data. Training a neural network model also includes comparing the output complex images with the target outputs by computing a phase-sensitive structural similarity index measure (PS-SSIM) between each of the output complex images and its corresponding target complex image, wherein the PS-SSIM is real-valued and varies with phases of the output complex image and phases of the target complex image, and adjusting the neural network model based on the comparison.

Abstract: A magnetic resonance (MR) image processing system is provided. The system includes an MR image processing computing device that includes at least one processor. The processor is programmed to execute a neural network model configured to receive crude MR data as an input and output processed MR images associated with the crude MR data, the crude MR data and the processed MR images having the first number of dimensions. The processor is also programmed to receive a pair of pristine data and corrupted data both having a second number of dimensions lower than the first number of dimensions. The corrupted data are the pristine data added with primitive features. The processor is further programmed to train the neural network model using the pair of the pristine data and the corrupted data. The trained neural network model is configured to change primitive features associated with the crude MR data.

Abstract: A computer-implemented method of processing complex magnetic resonance (MR) images is provided. The method includes receiving a pair of corrupted complex data and pristine complex images. The method also includes training a neural network model using the pair by inputting the corrupted complex data to the neural network model, setting the pristine complex images as target outputs, and processing the corrupted complex data using the neural network model to derive output complex images of the corrupted complex data. Training a neural network model also includes comparing the output complex images with the target outputs by computing a phase-sensitive structural similarity index measure (PS-SSIM) between each of the output complex images and its corresponding target complex image, wherein the PS-SSIM is real-valued and varies with phases of the output complex image and phases of the target complex image, and adjusting the neural network model based on the comparison.

Abstract: A system and method for localizing a deep brain stimulation electrode in vivo in a subject or object is provided. A magnetic resonance imaging system obtains MR image data from a volume-of-interest by way of a zero echo time (ZTE) or ultrashort echo time (UTE) pulse sequence, with one or more of a phase domain image and a magnitude domain image being analyzed from the MR image data acquired by the ZTE or UTE pulse sequence. One or more electrodes are localized within the volume-of-interest based on an analysis of the phase domain image and/or magnitude domain image. In localizing the electrodes, a multi-scale correlation-based analysis of the volume-of-interest is performed to estimate at least one of an electrode center and electrode contact locations of the electrode, with the localization being achieved with a fast scan-time and with a high level of accuracy and precision.

Abstract: A system and method for localizing a deep brain stimulation electrode in vivo in a subject or object is provided. A magnetic resonance imaging system obtains MR image data from a volume-of-interest by way of a zero echo time (ZTE) or ultrashort echo time (UTE) pulse sequence, with one or more of a phase domain image and a magnitude domain image being analyzed from the MR image data acquired by the ZTE or UTE pulse sequence. One or more electrodes are localized within the volume-of-interest based on an analysis of the phase domain image and/or magnitude domain image. In localizing the electrodes, a multi-scale correlation-based analysis of the volume-of-interest is performed to estimate at least one of an electrode center and electrode contact locations of the electrode, with the localization being achieved with a fast scan-time and with a high level of accuracy and precision.

Abstract: An imaging apparatus that incorporates an RF coil assembly and RF shield as part of a magnetic resonance imaging (MRI) system is disclosed. The imaging apparatus includes an MRI system having a plurality of gradient coils, an RF coil former having inner and outer surfaces, an RF shield positioned on the outer surface of the RF coil former so as to be formed about the RF coil former, and an RF coil positioned on the inner surface of the RF coil former, with the RF coil coupled to a pulse generator to emit an RF pulse sequence and receive resulting MR signals from a subject of interest. The RF coil former comprises a generally cylindrical member having an indented portion indented in a radial direction inwardly from the outer surface, with the RF shield conforming to the RF coil former so as to also have an indented portion.

Abstract: An imaging apparatus that incorporates an RF coil assembly and RF shield as part of a magnetic resonance imaging (MRI) system is disclosed. The imaging apparatus includes an MRI system having a plurality of gradient coils, an RF coil former having inner and outer surfaces, an RF shield positioned on the outer surface of the RF coil former so as to be formed about the RF coil former, and an RF coil positioned on the inner surface of the RF coil former, with the RF coil coupled to a pulse generator to emit an RF pulse sequence and receive resulting MR signals from a subject of interest. The RF coil former comprises a generally cylindrical member having an indented portion indented in a radial direction inwardly from the outer surface, with the RF shield conforming to the RF coil former so as to also have an indented portion.

Abstract: A system and method for multi-spectral MR imaging near metal include a computer programmed to calculate an MR pulse sequence comprising a plurality of RF pulses configured to excite spins in an imaging object and comprising a plurality of volume selection gradients and determine a plurality of distinct offset frequency values. For each respective determined offset frequency value, the computer is programmed to execute the MR pulse sequence having a central transmit frequency and a central receive frequency of the MR pulse sequence set to the respective determined offset frequency value. The computer is also programmed to acquire a three-dimensional (3D) MR data set for each MR pulse sequence execution and generate a composite image based on data from each of the acquired 3D MR data sets.

Abstract: An integrated gamma ray detector ring and RF coil assembly includes a first RF coil section and a gamma ray detector ring with a first end and a second end. The first end of the gamma ray detector ring is electrically coupled to the first RF coil section. The assembly also includes a second RF coil section that is electrically coupled to the second end of the gamma ray detector ring.

Abstract: Techniques for designing RF pulses may be configured to produce improved magnitude profiles of the resulting magnetization by relaxing the phase constraint and optimizing the phase profiles. In one embodiment, a spinor-based, optimal control, optimal phase technique may be used to design arbitrary-tip-angle (e.g., large and small tip angle) RF pulses (both parallel transmission and single channel). In another embodiment, small tip angle RF pulses (both parallel transmission and single channel) may be designed using a small-tip-angle (STA) pulse design without phase constraint that is formulated as a parameter optimization problem.

Abstract: A system and method for multi-spectral MR imaging near metal include a computer programmed to calculate an MR pulse sequence comprising a plurality of RF pulses configured to excite spins in an imaging object and comprising a plurality of volume selection gradients and determine a plurality of distinct offset frequency values. For each respective determined offset frequency value, the computer is programmed to execute the MR pulse sequence having a central transmit frequency and a central receive frequency of the MR pulse sequence set to the respective determined offset frequency value. The computer is also programmed to acquire a three-dimensional (3D) MR data set for each MR pulse sequence execution and generate a composite image based on data from each of the acquired 3D MR data sets.

Abstract: Techniques for designing RF pulses may be configured to produce improved magnitude profiles of the resulting magnetization by relaxing the phase constraint and optimizing the phase profiles. In one embodiment, a spinor-based, optimal control, optimal phase technique may be used to design arbitrary-tip-angle (e.g., large and small tip angle) RF pulses (both parallel transmission and single channel). In another embodiment, small tip angle RF pulses (both parallel transmission and single channel) may be designed using a small-tip-angle (STA) pulse design without phase constraint that is formulated as a parameter optimization problem.

Abstract: A system and method for transmitting multiple radio frequency (RF) channels via an RF coil assembly are provided. An RF coil assembly having a number of coil elements may be configured to transmit a number of RF channels which is less than the number of coil elements thereof. Some implementations may use signal splitters for some or all of the RF channels to produce driving inputs for each coil element. By using more coil elements than RF channels, various embodiments may exhibit increased power efficiency and improved B1 uniformity.

Abstract: A system and method for transmitting multiple radio frequency (RF) channels via an RF coil assembly are provided. An RF coil assembly having a number of coil elements may be configured to transmit a number of RF channels which is less than the number of coil elements thereof. Some implementations may use signal splitters for some or all of the RF channels to produce driving inputs for each coil element. By using more coil elements than RF channels, various embodiments may exhibit increased power efficiency and improved B1 uniformity.

Abstract: An RF coil apparatus for generating an elliptical polarization field includes an RF coil assembly having a pair of independent drive channels connected thereto. The drive channels are driven such that an elliptical polarization field is generated in a volume-of-interest within the RF coil assembly. The elliptical polarization field is generated about a subject having a generally elliptical cross-section disposed within the volume-of-interest.

Abstract: A magnetic resonance imaging assembly is provided. The assembly includes a magnet assembly defining a scanning bore along a z-direction. The assembly further includes a surface coil assembly positioned within the scanning bore. The surface coil assembly receives an imaging field. The surface coil assembly comprises a first surface coil positioned along the z-direction. The first surface coil is induced with a first coil current comprised of a first coil amplitude and a first coil phase. The surface coil assembly includes a second surface coil positioned along said z-direction. The second surface coil is induced with a second coil current comprised of a second coil amplitude and a second coil phase. The second coil phase is varied from the first coil phase to correct asymmetries within the imaging field.

Abstract: An integrated, multi-modality imaging technique is disclosed. The embodiment described combines a split-magnet MRI system with a digital x-ray system. The two systems are employed together to generate images of a subject in accordance with their individual physics and imaging characteristics. The images may be displaced in real time, such as during a surgical intervention. The images may be registered with one another and combined to form a composite image in which tissues or objects difficult to image in one modality are visible. By appropriately selecting the position of an x-ray source and detector, and by programming a desired corresponding slice for MRI imaging, useful combined images may be obtained and displayed.

Abstract: A method for processing digital images includes acquiring a phase difference image which includes one or more phase wraps, creating a modulated phase difference image from the phase difference image, comparing the modulated phase difference image to the phase difference image to locate areas in the phase difference image to be unwrapped, and unwrapping the phase difference image based on the areas located in the comparing step. The unwrapping step is performed by replacing wrapped pixels in the phase difference image with pixels in the modulated phase difference image plus an integer multiple of &pgr;. The integer multiplier is computed by comparing overlapping pixels in the image segments. This has a smoothing effect causing the wrapped pixels in the phase difference image to become unwrapped. As a result of this pixel replacement process, an image of improved quality and information content is produced compared with conventional methods.

Abstract: A method for processing digital images includes acquiring a phase difference image which includes one or more phase wraps, creating a modulated phase difference image from the phase difference image, comparing the modulated phase difference image to the phase difference image to locate areas in the phase difference image to be unwrapped, and unwrapping the phase difference image based on the areas located in the comparing step. The unwrapping step is performed by replacing wrapped pixels in the phase difference image with pixels in the modulated phase difference image plus an integer multiple of &pgr;. The integer multiplier is computed by comparing overlapping pixels in the image segments. This has a smoothing effect causing the wrapped pixels in the phase difference image to become unwrapped. As a result of this pixel replacement process, an image of improved quality and information content is produced compared with conventional methods.

Abstract: A medical appliance for use in magnetic resonance imaging procedures. A guidewire for vascular procedures is formed by a coaxial cable acting as antenna in a magnetic resonance imaging system.