Abstract: 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*2 decay, the following steps are implemented: (S1) acquire three fat-water images, respectively corresponding to the echo times TE1, TE2, TE3 after the RF excitation pulse, wherein first and third fat-water images exhibit the same phase, (S2) calculate a T*2 map from the two equiphase images, (S3) correct the T*2 influence in one of the two equiphase fat-water images and in the counter-phase fat-water image, and (S4) reconstruct a pure T*2-corrected fat image and a pure T*2-corrected water image according to the two-point Dixon method on the basis of the T*2-corrected equiphase and counter-phase fat-water images in Step (S3).

Abstract: 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.

Abstract: 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.

Abstract: A method is for correcting inhomogeneities in an image that is recorded from an examination object. The method includes recording an image to be corrected, calculating a correction image from the image to be corrected and correcting the recorded image with the aid of the correction image in order to produce a normalized image by multiplying the correction image by the image to be corrected. When calculating the correction images, the pixels in the vicinity of the imaged examination object are identified with the aid of a signal intensity that is lower than a limiting value. Further, these pixels are allocated signal intensities that in each case are a function of the signal intensity of the pixels in the respective neighborhood.

Abstract: 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.

Abstract: 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.

Abstract: In a method and apparatus for generating a magnetic resonance image of a contiguous region of a human body on the basis of partial parallel acquisition (PPA) by excitation of nuclear spins and measurement of radio-frequency signals indicating the excited spins, the spin excitation is implemented in steps with measurement of an RF response signal simultaneously in each of a number of N component coils. A number of response signals thus are acquired that, for each component coil, form an incomplete data set (40) of acquired RF signals. Additional acquired calibration data points exist for each incomplete data set. The N incomplete data sets are acquired to a subset of M reduced, incomplete data sets on the basis of an N×M reduction matrix, so that M reduced, incomplete data sets are obtained, M complete data sets are formed on the basis of an N×M reconstruction matrix with the non-measured lines of the M reduced, incomplete data sets being reconstructed from all N incomplete data sets.

Abstract: In a data acquisition and reconstruction method for magnetic resonance (MR) tomography, and a corresponding MR tomography apparatus, a blade-like sampling of k-space according to the PROPELLER method using a number of reception coils ensures with partial under-sampling of at least one blade of k-space such that the under-sampling ensues by regular omission of k-space lines in both boundary regions (with regard to the phase-encoding direction ky) of a blade such that only data in each A-th line of said boundary regions are acquired; with no k-space lines being omitted in the central region (with regard to the ky-direction) and thus at least one coil calibration line is obtained, selection of a suitable PPA method for completion of the blades and determination of the necessary coil calibration data necessary for the PPA reconstruction of a partial under-sampled blade from the central completely sampled region of said blade.

Abstract: In a data acquisition and reconstruction method for magnetic resonance (MR) tomography, and a corresponding MR tomography apparatus, a blade-like sampling of k-space according to the PROPELLER method using a number of reception coils ensures with partial under-sampling of at least one blade of k-space such that the under-sampling ensues by regular omission of k-space lines in both boundary regions (with regard to the phase-encoding direction ky) of a blade such that only data in each A-th line of said boundary regions are acquired; with no k-space lines being omitted in the central region (with regard to the ky-direction) and thus at least one coil calibration line is obtained, selection of a suitable PPA method for completion of the blades and determination of the necessary coil calibration data necessary for the PPA reconstruction of a partial under-sampled blade from the central completely sampled region of said blade.

Abstract: In the operation of a magnetic resonance system, an RF excitation coil emits an excitation pulse such that nuclei in an examination subject are excited to emit of magnetic resonance signals. A number of local coils acquire the magnetic resonance signals emitted from the examination subject, with the magnetic resonance signals acquired by the local coils being coded in frequency space. An evaluation device accepts the magnetic resonance signals acquired by the local coils or accepts intermediate signals derived therefrom via one transmission channel per signal, and corrects the accepted signals using correction signals. The evaluation device uses the corrected signals reconstructing an image of the examination subject. The evaluation device determines the correction signals for all signals to be corrected using the same reference signal.

Abstract: In the operation of a magnetic resonance system, an RF excitation coil emits an excitation pulse such that nuclei in an examination subject are excited to emit of magnetic resonance signals. A number of local coils acquire the magnetic resonance signals emitted from the examination subject, with the magnetic resonance signals acquired by the local coils being coded in frequency space. An evaluation device accepts the magnetic resonance signals acquired by the local coils or accepts intermediate signals derived therefrom via one transmission channel per signal, and corrects the accepted signals using correction signals. The evaluation device uses the corrected signals reconstructing an image of the examination subject. The evaluation device determines the correction signals for all signals to be corrected using the same reference signal.

Abstract: In a method and apparatus for generating a magnetic resonance image of a contiguous region of a human body on the basis of partial parallel acquisition (PPA) by excitation of nuclear spins and measurement of radio-frequency signals indicating the excited spins, the spin excitation is implemented in steps with measurement of an RF response signal simultaneously in each of a number of N component coils. a number of response signals thus are acquired that, for each component coil, form an incomplete data set (40) of acquired RF signals. Additional acquired calibration data points exist for each incomplete data set. The N incomplete data sets are acquired to a subset of M reduced, incomplete data sets on the basis of an N×M reduction matrix, so that M reduced, incomplete data sets are obtained, M complete data sets are formed on the basis of an N×M reconstruction matrix with the non-measured lines of the M reduced, incomplete data sets being reconstructed from all N incomplete data sets.

Abstract: A method is for correcting inhomogeneities in an image that is recorded from an examination object. The method includes recording an image to be corrected, calculating a correction image from the image to be corrected and correcting the recorded image with the aid of the correction image in order to produce a normalized image by multiplying the correction image by the image to be corrected. When calculating the correction images, the pixels in the vicinity of the imaged examination object are identified with the aid of a signal intensity that is lower than a limiting value. Further, these pixels are allocated signal intensities that in each case are a function of the signal intensity of the pixels in the respective neighborhood.