Abstract: The disclosure is directed to an Echo-Planar-Imaging (EPI) magnetic resonance imaging techniques combined with a variable-density undersampling scheme. The technique comprises generating an RF pulse, applying a switched frequency-encoding read out gradient in a variable time interval, and applying simultaneously an intermittently blipped low-magnitude phase-encoding gradient with a variable value of an integral of the phase-encoding gradient. The aforementioned steps are carried out such that the k-space is at least partially undersampled and the time interval of one read out gradient is varied depending on the integral of the phase encoding gradient, such that a ratio between the variable time interval of the read out gradient and the integral of the corresponding phase encoding gradient is kept above or at a predetermined constant value, which is related to a predetermined criteria of image quality.

Abstract: The disclosure is directed to an Echo-Planar-Imaging (EPI) magnetic resonance imaging techniques combined with a variable-density undersampling scheme. The technique comprises generating an RF pulse, applying a switched frequency-encoding read out gradient in a variable time interval, and applying simultaneously an intermittently blipped low-magnitude phase-encoding gradient with a variable value of an integral of the phase-encoding gradient. The aforementioned steps are carried out such that the k-space is at least partially undersampled and the time interval of one read out gradient is varied depending on the integral of the phase encoding gradient, such that a ratio between the variable time interval of the read out gradient and the integral of the corresponding phase encoding gradient is kept above or at a predetermined constant value, which is related to a predetermined criteria of image quality.

Abstract: In a method for readout segmented magnetic resonance imaging (MRI) of an examination object, k-space is acquired in a plurality of segments along a readout direction using a parallel imaging (PI) technique. K-space in a first segment is acquired with a first acceleration factor, and k-space in a second segment is acquired with a second acceleration factor different from the first acceleration factor.

Abstract: Techniques are disclosed for recording magnetic resonance data with a magnetic resonance facility, wherein a three-dimensional echo-planar imaging sequence is used whereby following a single excitation period (e.g. “module”) in an echo train, an echo count of k-space rows is read out in a read-out direction in the k-space, and interchanging takes place between these rows by means of gradient pulses of the two phase encoding directions.

Abstract: A method for obtaining magnetic resonance imaging (MRI) echo-planar image (EPI) data, including providing a homogeneous, static background field; providing a gradient field to select a slice of an object for imaging; applying Radio-frequency (RF) pulses to excite magnetic resonance in the selected slice; and measuring a radio frequency signal emitted by the selected slice containing image data. The RF pulses are repeatedly applied separated by a time period shorter than a recovery time of static material in the selected slice such that the static material remains in a state of magnetic saturation, while dynamic material arriving within the slice since a previous RF pulse is not magnetically saturated.

Abstract: In a method and magnetic resonance (MR) apparatus for echo-planar MR imaging with which MR signals are entered in raw-data space with a zigzag-type trajectory, a sequence of readout gradients and phase-encoding gradients is applied such that a zigzag-type undersampled trajectory in raw-data space is filled, such that with the signal echoes being shifted by up to a quarter of the acquired raw-data space in the direction of the readout axis. Image data are reconstructed using a parallel-imaging reconstruction algorithm that operates on the raw data acquired in the zigzag-type trajectory, based on an interlaced Fourier transform.

Abstract: Techniques are disclosed for recording magnetic resonance data with a magnetic resonance facility, wherein a three-dimensional echo-planar imaging sequence is used whereby following a single excitation period (e.g. “module”) in an echo train, an echo count of k-space rows is read out in a read-out direction in the k-space, and interchanging takes place between these rows by means of gradient pulses of the two phase encoding directions.

Abstract: In a method for readout segmented magnetic resonance imaging (MRI) of an examination object, k-space is acquired in a plurality of segments along a readout direction using a parallel imaging (PI) technique. K-space in a first segment is acquired with a first acceleration factor, and k-space in a second segment is acquired with a second acceleration factor different from the first acceleration factor.

Abstract: In a method and magnetic resonance (MR) apparatus for echo-planar acquisition of MR images using multiple reception coils, an RF excitation pulse is radiated to generate transverse magnetization, and a temporal sequence of a readout gradient is activated with alternating positive and negative values, thereby producing MR signal echoes. Multiple phase-encoding gradients are activated in a temporal sequence with a value of the phase-encoding gradients being maximum when a value of the readout gradients is minimum, and vice versa. A time period during which a single phase-encoding gradient is applied is at least a quarter of a time interval between two MR signal echoes. The MR signal echoes are read with the multiple reception coils in a trajectory in k-space, continuously without interruption during the readout gradient. The trajectory does not completely fill k-space with raw data in an edge region according to the Nyquist condition.

Abstract: A method for obtaining magnetic resonance imaging (MRI) echo-planar image (EPI) data, including providing a homogeneous, static background field; providing a gradient field to select a slice of an object for imaging; applying Radio-frequency (RF) pulses to excite magnetic resonance in the selected slice; and measuring a radio frequency signal emitted by the selected slice containing image data. The RF pulses are repeatedly applied separated by a time period shorter than a recovery time of static material in the selected slice such that the static material remains in a state of magnetic saturation, while dynamic material arriving within the slice since a previous RF pulse is not magnetically saturated.

Abstract: In a method and apparatus for magnetic resonance imaging, a particularly quiet magnetic resonance sequence, uses echo-planar imaging with at least one gradient switching in a readout direction, wherein the at least one gradient switching in the readout direction has a slew rate that is less than a maximum slew rate defined by system specification parameters of the magnetic resonance apparatus.

Abstract: In a method and magnetic resonance (MR) apparatus for echo-planar acquisition of MR images using multiple reception coils, an RF excitation pulse is radiated to generate transverse magnetization, and a temporal sequence of a readout gradient is activated with alternating positive and negative values, thereby producing MR signal echoes. Multiple phase-encoding gradients are activated in a temporal sequence with a value of the phase-encoding gradients being maximum when a value of the readout gradients is minimum, and vice versa. A time period during which a single phase-encoding gradient is applied is at least a quarter of a time interval between two MR signal echoes. The MR signal echoes are read with the multiple reception coils in a trajectory in k-space, continuously without interruption during the readout gradient. The trajectory does not completely fill k-space with raw data in an edge region according to the Nyquist condition.

Abstract: In a method and magnetic resonance (MR) apparatus for echo-planar MR imaging with which MR signals are entered in raw-data space with a zigzag-type trajectory, a sequence of readout gradients and phase-encoding gradients is applied such that a zigzag-type undersampled trajectory in raw-data space is filled, such that with the signal echoes being shifted by up to a quarter of the acquired raw-data space in the direction of the readout axis. Image data are reconstructed using a parallel-imaging reconstruction algorithm that operates on the raw data acquired in the zigzag-type trajectory, based on an interlaced Fourier transform.

Abstract: In a method and apparatus for echo planar magnetic resonance (MR) imaging sequence of phase encoding gradient fields and a sequence of readout gradient fields are applied in order to produce a well-defined zigzag-type trajectory for entering raw data into k-space. Zigzag-type trajectories can be achieved that have flanks without curvature, or without significant curvature. Cartesian methods for image reconstruction of parallel MR imaging are applied to echo planar MR imaging with such zigzag-type trajectories.

Abstract: In a method and apparatus for magnetic resonance imaging, a particularly quiet magnetic resonance sequence, uses echo-planar imaging with at least one gradient switching in a readout direction, wherein the at least one gradient switching in the readout direction has a slew rate that is less than a maximum slew rate defined by system specification parameters of the magnetic resonance apparatus.

Abstract: In a method and apparatus for echo planar magnetic resonance (MR) imaging sequence of phase encoding gradient fields and a sequence of readout gradient fields are applied in order to produce a well-defined zigzag-type trajectory for entering raw data into k-space. Zigzag-type trajectories can be achieved that have flanks without curvature, or without significant curvature. Cartesian methods for image reconstruction of parallel MR imaging are applied to echo planar MR imaging with such zigzag-type trajectories.

Abstract: In a magnetic resonance imaging method and apparatus, magnetic resonance data are acquired (an examination subject) using a zoomed method, and reconstruction of the image of the examination subject is undertaken using a parallel imaging reconstruction method.

Abstract: In a magnetic resonance imaging method and apparatus, magnetic resonance data are acquired (an examination subject) using a zoomed method, and reconstruction of the image of the examination subject is undertaken using a parallel imaging reconstruction method.

Abstract: In a method for magnetic resonance imaging using a partial parallel acquisition technique with a non-Cartesian occupation of k-space, a number of antennas disposed around an imaging volume for reception of magnetic resonance signals and the magnetic resonance signals in the imaging volume are spatially coded by magnetic gradient fields, such that k-space for each antenna is only incompletely occupied with magnetic resonance signals with at least one trajectory proceeding around the origin of k-space. From the reception signals of each antenna, missing sample values of the trajectory that lie on a straight-line segment extending from the origin are determined in k-space according to a weighting with weighting factors from sample values of the trajectory that likewise lie on the straight lines, such that each k-space is completely occupied. A partial image of the imaging area is generated from each completely occupied k-space by means of a Fourier transformation.

Abstract: In a method for magnetic resonance imaging using a partial parallel acquisition technique with a non-Cartesian occupation of k-space, a number of antennas disposed around an imaging volume for reception of magnetic resonance signals and the magnetic resonance signals in the imaging volume are spatially coded by magnetic gradient fields, such that k-space for each antenna is only incompletely occupied with magnetic resonance signals with at least one trajectory proceeding around the origin of k-space. From the reception signals of each antenna, missing sample values of the trajectory that lie on a straight-line segment extending from the origin are determined in k-space according to a weighting with weighting factors from sample values of the trajectory that likewise lie on the straight lines, such that each k-space is completely occupied. A partial image of the imaging area is generated from each completely occupied k-space by means of a Fourier transformation.