Patent application number | Description | Published |
20090134870 | METHOD AND DEVICE FOR MAGNETIC RESONANCE IMAGING ON THE BASIS OF A PARTIALLY PARALLEL ACQUISITION (PPA) - In a method, apparatus and computer-readable medium for magnetic resonance imaging of a contiguous region of a human body on the basis of partially parallel acquisition (PPA) by excitation of nuclear spins and measurement of radio-frequency signals representing the excited spins, are implemented. A k-space single channel reference image [R_kal] is calculated from the previously measured reference lines of a sub-coil series of N sub-coils with a phase-sensitive combination method. A GRAPPA coefficient matrix [W] is calculated by solving the equation system [R_kal]=[W]×[I_kal] wherein [I_kal] represents one block from the sub-coil series. A k-space single channel image [R] is successively completed by applying [W] to successive blocks [I_z] shifted relative to one another, the blocks [I_z] being of a previously measured, under-sampled sub-coil series of the N sub-coils, and [R] is transformed into image space. | 05-28-2009 |
20090201021 | PHASE CORRECTION METHOD - A method corrects for a phase error in an MR image, in which MR signals of an examination subject are acquired, complex images of the examination subject are generated, phase differences of the phase values for various image points of the complex images are established with an averaged phase value of image points from a first surrounding region of a respective image point, and a phase correction is executed dependent on how well the phase differences correspond to a predetermined phase value, where the order of the image points in which the phase correction is implemented is dependent on how well the phase values in the image points correspond to the predetermined phase value. | 08-13-2009 |
20100052674 | Method for determining an attenuation map for use in positron emission tomography and for the use of homogeneity information relating to the magnetic resonance magnetic field - A method is disclosed for determining an attenuation map for use in positron emission tomography and for the use of homogeneity information relating to the magnetic resonance magnetic field, in particular for the purpose of determining shim settings, within the scope of a single magnetic resonance image recording. In at least one embodiment of the method, a first and a second image data record are firstly recorded with a three-dimensional gradient echo sequence during a first and a second echo time, respectively, with the phase difference between the water and the fat signal amounting to zero during the first echo time and amounting to 180 degrees during the second echo time. The attenuation map is determined from fat/water ratios obtained from the image data records by way of a Dixon technology, in particular a 2-point Dixon technology. In at least one embodiment, all voxels with a signal intensity below a first threshold value are excluded at least for the second image data record by using a mask and only the non excluded voxels of the first and second image data record are taken into consideration in order to determine the homogeneity information from the phase differences of adjacent voxels. | 03-04-2010 |
20100072998 | MAGNETIC RESONANCE METHOD AND DEVICE TO AUTOMATICALLY DIFFERENTIATE WATER-DOMINATED AND FAT-DOMINATED TISSUE - In a magnetic resonance method and system to automatically differentiate whether a pixel of an MR image acquired with magnetic resonance system originated from fat-dominated tissue or water-dominated tissue, only one spin echo-based magnetic resonance signal per pixel is acquired at a point in time at which the phase of a magnetic resonance signal of aqueous tissue has a phase opposite to the phase of a magnetic resonance signal of fat tissue. The phase angle of the pixel is then calculated, a base phase at the pixel depending on the magnetic resonance system is determined, and a corrected phase angle of the pixel is determined from the phase angle and the base phase. Whether the pixel originated from fat-dominated tissue or water-dominated tissue is then determined using the corrected phase angle of the pixel. | 03-25-2010 |
20100123460 | MAGNETIC RESONANCE TOMOGRAPHY METHOD AND APPARATUS WITH SEPARATION OF FAT AND WATER IMAGES ACCORDING TO THE TWO-POINT DIXON METHOD DEPENDENT ON T*2 DECAY - In a magnetic resonance tomography method and apparatus for separation of fat and water images according to the two-point Dixon method dependent on the T* | 05-20-2010 |
20100201364 | PHASE CORRECTION METHOD - A method corrects for a phase error in an MR image, in which MR signals of an examination subject are acquired, complex images of the examination subject are generated, phase differences of the phase values for various image points of the complex images are established with an averaged phase value of image points from a first surrounding region of a respective image point, and a phase correction is executed dependent on how well the phase differences correspond to a predetermined phase value, where the order of the image points in which the phase correction is implemented is dependent on how well the phase values in the image points correspond to the predetermined phase value. | 08-12-2010 |
20100244830 | MAGNETIC RESONANCE METHOD AND DEVICE TO DIFFERENTIATE AMONG PIXELS REPRESENTING A SILICON-DOMINATED SUBSTANCE, WATER-DOMINATED TISSUE AND FAT-DOMINATED TISSUE - In a magnetic resonance method and device for automatic differentiation of respective pixels as representing either a silicon-dominated substance, or fat-dominated tissue, or water-dominated tissue, a first magnetic resonance signal and a second magnetic resonance signal are acquired per pixel, wherein the first magnetic resonance signal per pixel is acquired at a point in time at which the phase of a magnetic resonance signal originating from water-containing tissue exhibits a phase opposite to the phase of a magnetic resonance signal originating from fat-containing tissue, and the second magnetic resonance signal is acquired per pixel at a point in time at which the phase of the magnetic resonance signal originating from water-containing tissue exhibits a phase identical to the phase of the magnetic resonance signal originating from fat-containing tissue, and the phase of a magnetic resonance signal originating from a silicon-containing substance exhibits a phase opposite to the phase of the magnetic resonance signal originating from water-containing or fat-containing tissue. A first intermediate result is determined that indicates whether the pixel represents water-dominated tissue or fat-dominated tissue on the basis of first magnetic resonance signals. A second intermediate result is determined that indicates whether the pixel represents the silicon-dominated substance on the basis of second magnetic resonance signals. The pixel is designated as representing water-dominated tissue, fat-dominated tissue or the silicon-dominated substance on the basis of the first intermediate result and the second intermediate result. | 09-30-2010 |
20120025823 | METHOD AND DEVICE FOR MAGNETIC RESONANCE IMAGING - In a methods and devices for magnetic resonance (MR) imaging, an MR data acquisition is implemented repeatedly in which an examination subject is exposed to an alternating magnetic field with a frequency before the readout sequence. The signal values acquired after the preparation of the magnetization with alternating fields of respectively different frequencies are evaluated. Magnetic field data that contain information about the curve of the basic field are used to implement the MR data acquisitions, such as to establish the frequencies, and/or in the evaluation of the signal values. | 02-02-2012 |
20120119737 | PHASE-DEPENDENT MAGNETIC-RESONANCE IMAGING WITH MULTIPLE COILS - In a method and magnetic resonance system to determine a magnetic resonance (MR) image of an examination subject, wherein multiple coil-specific MR data sets that are acquired by multiple coils are used for the MR image. Each pixel of the MR image is determined from at least two coil-specific MR data sets of different coils ( | 05-17-2012 |