Abstract: The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of a MR device (1). It is an object of the invention to enable efficient spiral MR imaging even in situations of strong Bo inhomogeneity. The method of the invention comprises: subjecting the object (10) to an imaging sequence comprising at least one RF excitation pulse and sinusoidally modulated magnetic field gradients, acquiring MR signals along two or more spiral k-space trajectories (31, 32, 33) as determined by the sinusoidal modulation of the magnetic field gradients, wherein the origins of the spiral k-space trajectories are offset from each other, and reconstructing an MR image from the acquired MR signals. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).

Abstract: Disclosed herein is a medical system (100, 300) comprising a memory (110) storing machine executable instructions (120). The medical system further comprises a computational system (104).

Abstract: A method of magnetic resonance (MR) imaging includes a phantom that is inexpensive to produce and enables simple, practical and fast assessment of image sharpness, in particular for checking image quality of MR imaging with spiral acquisition. The method includes subjecting a phantom, which comprises a volume filled with a bulk of granules of solid material surrounded by a liquid, to an imaging sequence, acquiring MR signals from the phantom, reconstructing an MR image from the acquired MR signals, and deriving a measure of the local image sharpness in two or more different image regions from the MR image, wherein each image region is a representation of a part of the phantom volume.

Abstract: The invention relates to a method of MR imaging. It is an object of the invention to provide a phantom that is inexpensive to produce and enables simple, practical and fast assessment of image sharpness, in particular for checking tire image quality of MR imaging with spiral acquisition. The method of the invention comprises the steps of:—subjecting a phantom (19), which comprises a volume filled with a bulk of granules of solid material surrounded by a liquid, to an imaging sequence,—acquiring MR signals from the phantom (19),—reconstructing an MR image from the acquired MR signals, and—deriving a measure of the local image sharpness in two or more different image regions from the MR image, wherein each image region is a representation of a part of the phantom volume. Moreover, the invention relates to a MR device (1) and to a phantom for MR imaging.

Abstract: The invention relates to a method of MR imaging of an object (10) positioned in an examination volume of a MR device (1). It is an object of the invention to enable efficient spiral MR imaging even in situations of strong Bo inhomogeneity. The method of the invention comprises: subjecting the object (10) to an imaging sequence comprising at least one RF excitation pulse and sinusoidally modulated magnetic field gradients, acquiring MR signals along two or more spiral k-space trajectories (31, 32, 33) as determined by the sinusoidal modulation of the magnetic field gradients, wherein the origins of the spiral k-space trajectories are offset from each other, and reconstructing an MR image from the acquired MR signals. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).

Abstract: The invention provides for a magnetic resonance imaging system. Instructions cause a processor (136) controlling the magnetic resonance imaging system to modify (200) pulse sequence data by omitting at least some of the phase encodings (408) that encode for volumes outside of the field of view. The pulse sequence data specifies the acquisition of a stack (128) of two dimensional slices of a field of view (126). The pulse sequence data further specifies phase encoding in a direction (130) perpendicular to the two dimensional slices. The pulse sequence data specifies a maximum SEMAC factor (400). The maximum SEMAC factor specifies a maximum number of phase encoding steps in the perpendicular direction for each of the two dimensional slices. The instructions further cause the processor to determine (202) a slice SEMAC factor for each of the stack of two dimensional slices. The slice SEMAC factor is determined by counting the phase encoding steps that encode for regions within the field of view.

Abstract: A magnetic resonance imaging (MRI) system (600) obtains magnetic resonance (MR) images of a volume. The MRI system includes at least one controller (610) configured to perform a preparation scan (103, 301) to acquire preparation echo phase information (105, PEPI) for a plurality of dynamics of a scan (300); output a plurality of pulse sequences (200), each pulse sequence is configured for a corresponding dynamic of the plurality of dynamics of the scan and includes a navigator sequence (204) and an image sequence (206); acquire navigation and image information (111, 117) for each corresponding pulse sequence of the plurality of pulse sequences; and/or form corrected image information (125) by correcting echo phase information in accordance with the preparation echo phase information, correcting at least one of gradient delay or frequency offset of the image information in accordance with the navigation information.

Abstract: The invention provides for a magnetic resonance imaging system. Instructions cause a processor (136) controlling the magnetic resonance imaging system to modify (200) pulse sequence data by omitting at least some of the phase encodings (408) that encode for volumes outside of the field of view. The pulse sequence data specifies the acquisition of a stack (128) of two dimensional slices of a field of view (126). The pulse sequence data further specifies phase encoding in a direction (130) perpendicular to the two dimensional slices. The pulse sequence data specifies a maximum SEMAC factor (400). The maximum SEMAC factor specifies a maximum number of phase encoding steps in the perpendicular direction for each of the two dimensional slices. The instructions further cause the processor to determine (202) a slice SEMAC factor for each of the stack of two dimensional slices. The slice SEMAC factor is determined by counting the phase encoding steps that encode for regions within the field of view.

Abstract: A magnetic resonance imaging (MRI) system (600) for obtaining magnetic resonance (MR) images of a volume. The MRI system may include at least one controller (610) which may be configured to perform a preparation scan (103, 301) to acquire preparation echo phase information (105, PEPI) for a plurality of dynamics of a scan (300); output a plurality of pulse sequences (200) each of which is configured for a corresponding dynamic of the plurality of dynamics of the scan and comprises a navigator sequence (204) and an image sequence (206); acquire navigation and image information (111, 117) for each corresponding pulse sequence of the plurality of pulse sequences; and/or form corrected image information (125) by correcting echo phase information of the image information in accordance with the preparation echo phase information, correcting at least one of gradient delay and frequency offset of the image information in accordance with the navigation information.