Abstract: Example apparatus and methods provide improved quantitative T2 mapping for magnetic resonance imaging (MRI). Conventional T2 (spin-spin) mapping in MRI may employ a spin echo with multiple echoes (SEMC) approach like the Carr-Purcell-Meiboom-Gill (CPMG) spin echo sequence. These conventional approaches may be negatively impacted by a slice profile effect that incorrectly and undesirably lowers the signal of a first echo and by a stimulated echo effect that incorrectly and undesirably raises the signal for even echoes. Example apparatus mitigate these issues by using a T2 preparation phase that uses three dimensional (3D) non-slice selective block RF pulses followed by a multi-echo data acquisition that uses an in-out k-space trajectory. The multi-echo acquisition may employ k-space segmentation to acquire one line of partition encodings per T2 preparation phase.

Abstract: The present invention relates to a parameter adjustment method. The parameter adjustment method used for statistical machine translation comprises: step 1: using a monolingual corpus to construct a language model required for translation; step 2: using a bilingual parallel corpus to construct a translation model; and step 3: using a target function to adjust a parameter. The method can solve problems in prior art that the parameter is easily over-fit or falls into a local optimum during a parameter adjustment process, and the method is easy to implement and can combine a larger number of features. In addition, the target function is convex; therefore, global optimum can be achieved in a training process.

Abstract: The present invention relates to a parameter adjustment method. The parameter adjustment method used for statistical machine translation comprises: step 1: using a monolingual corpus to construct a language model required for translation; step 2: using a bilingual parallel corpus to construct a translation model; and step 3: using a target function to adjust a parameter. The method can solve problems in prior art that the parameter is easily over-fit or falls into a local optimum during a parameter adjustment process, and the method is easy to implement and can combine a larger number of features. In addition, the target function is convex; therefore, global optimum can be achieved in a training process.

Abstract: Example apparatus and methods provide improved resolution over conventional magnetic resonance imaging (MRI) that is affected by the presence of metal (e.g., prosthetic hip) in the MRI field of view (FOV). Embodiments may excite a slice that is affected by a susceptibility effect produced by metal. Embodiments may excite the slice using a first pre-determined frequency and a plurality of scout frequency encodings. Embodiments may acquire nuclear magnetic resonance (NMR) signal data from the slice in response to the first pre-determined frequency and the plurality of scout frequency encodings and select frequency encodings to use to image the slice as a function of an amplitude of the NMR signal data. Frequency encodings are selected to produce data that will help account for distortions caused by the susceptibility effect.

Abstract: A method for automated magnetic field shimming in a MR imaging system includes generating RF excitation pulses in anatomy, generating slice select magnetic field gradients on a static magnetic field and generating a plurality of shimming routines. The method also includes acquiring maps of the static magnetic field between each shimming routine and determining a base function for each of the plurality of shimming coils from: (i) intermediate magnitudes and directions of the static magnetic field produced by each of the plurality of shimming coils during each shimming routine; and (ii) intermediate currents supplied to each of the plurality of shimming coils during each shimming routine. The method further includes determining updated magnitudes and directions of the static magnetic field produced by each of the plurality of shimming coils by expanding the determined base function for each of the plurality of shimming coils into low order polynomials.

Abstract: A method provides motion corrected MR image data in an MR imaging system. The method employs an imaging method for acquiring k-space data of a k-space data array during an imaging scan and the k-space data represents image data of a patient anatomical region. The method acquires k-space data associated with a central region of the k-space data array and subsequently acquires k-space data external to the central region of the k-space data array. The method acquires a motion signal indicating respiratory motion at least during the acquisition of the k-space data external to the central region and compares the motion signal with a predetermined threshold. The method identifies acquired k-space data corresponding to acquisition periods when the motion signal exceeds the threshold and excludes use of the identified acquired k-space data in image reconstruction using the remaining acquired k-space data.

Abstract: A system acquires MR image data of a portion of patient anatomy associated with spin lattice relaxation time in a rotating frame using an RF (Radio Frequency) signal generator and a magnetic field gradient generator. The RF (Radio Frequency) signal generator generates RF excitation pulses in anatomy and enables subsequent acquisition of associated RF echo data. The magnetic field gradient generator generates anatomical volume select magnetic field gradients for phase encoding and readout RF data acquisition in a three dimensional (3D) anatomical volume. The RF signal generator and the gradient generator use in order, a saturation pulse, a T1 spin lattice relaxation rotating frame preparation pulse sequence and a spoiler gradient, in acquiring image data of the 3D volume showing luminance contrast associated with T1 spin lattice relaxation in a rotating frame.

Abstract: A method provides motion corrected MR image data in an MR imaging system. The method employs an imaging method for acquiring k-space data of a k-space data array during an imaging scan and the k-space data represents image data of a patient anatomical region. The method acquires k-space data associated with a central region of the k-space data array and subsequently acquires k-space data external to the central region of the k-space data array. The method acquires a motion signal indicating respiratory motion at least during the acquisition of the k-space data external to the central region and compares the motion signal with a predetermined threshold. The method identifies acquired k-space data corresponding to acquisition periods when the motion signal exceeds the threshold and excludes use of the identified acquired k-space data in image reconstruction using the remaining acquired k-space data.

Abstract: A system acquires frequency domain components representing MR image data. An RF coil emits RF pulses for use in acquiring multiple individual frequency components corresponding to individual data elements in a 3D storage array in which the individual frequency components are successively acquired along radii from a designated center representing an origin to a boundary of the storage array. Angles of successive radii with respect to the origin are successively changed to substantially fill the storage array volume during acquisition of an MR dataset representing an MR image. A computation processor determines the angles of successive radii with respect to the origin, in response to data representing a reduction in at least one dimension of the 3D imaging volume represented by the storage array. A storage processor stores individual frequency components, acquired using the emitted RF pulses, in corresponding individual data elements in the array.

Abstract: An apparatus and method for obtaining diffusion weighted magnetic resonance images (DW-MRI) is described. The properties of the diffusion tensor in tissue are measured by applying a diffusion weighting gradient oriented along a plurality of measurement axes. The value of the magnetic field is increased by using as many of the magnetic gradient coils as are effective in contributing the gradient field strength along the axis being. In regions where the magnetic field gradient is increased, the echo time (TE) may be decreased, increasing the signal-to-noise ratio of the measurements. Alternatively, the number of measurements than are averaged to achieve a particular image quality may be decreased, reducing the patient exposure time.

Abstract: A system acquires frequency domain components representing MR image data. An RF coil emits RF pulses for use in acquiring multiple individual frequency components corresponding to individual data elements in a 3D storage array in which the individual frequency components are successively acquired along radii from a designated center representing an origin to a boundary of the storage array. Angles of successive radii with respect to the origin are successively changed to substantially fill the storage array volume during acquisition of an MR dataset representing an MR image. A computation processor determines the angles of successive radii with respect to the origin, in response to data representing a reduction in at least one dimension of the 3D imaging volume represented by the storage array. A storage processor stores individual frequency components, acquired using the emitted RF pulses, in corresponding individual data elements in the array.

Abstract: An apparatus and method for obtaining diffusion weighted magnetic resonance images (DW-MRI) is described. The properties of the diffusion tensor in tissue are measured by applying a diffusion weighting gradient oriented along a plurality of measurement axes. The value of the magnetic field is increased by using as many of the magnetic gradient coils as are effective in contributing the gradient field strength along the axis being. In regions where the magnetic field gradient is increased, the echo time (TE) may be decreased, increasing the signal-to-noise ratio of the measurements. Alternatively, the number of measurements than are averaged to achieve a particular image quality may be decreased, reducing the patient exposure time.