Abstract: A method of magnetic resonance (MR) imaging of an object includes: generating MR signals by subjecting the object to a number N of shots of a multi-echo imaging sequence comprising multi-slice RF pulses for simultaneously exciting two or more spatially separate image slices, with a phase offset in the slice direction being imparted to the MR signals; acquiring the MR signals that are received in parallel via a set of at least two RF coils having different spatial sensitivity profiles; and reconstructing a MR image for each image slice from the acquired MR signals using a parallel reconstruction algorithm, wherein the MR signal contributions from the different image slices are separated on the basis of the spatial encodings of the MR signals according to the spatial sensitivity profiles of the RF coils and of the phase offsets attributed to the respective image slices and shots.

Abstract: The invention relates to a method of MR imaging of an object (10) placed in an examination volume of a MR device (1).

Abstract: In an EPI acquisition sequence for magnetic resonance signals k-space is scanned along sets of lines in k-space along opposite propagation directions, e.g. odd and even lines in k-space. Phase errors that occur due to the opposite propagation directions are corrected for in a SENSE-type parallel imaging reconstruction. The phase error distribution in image space may be initially estimated, calculated form the phase difference between images reconstructed from magnetic resonance signals acquired from the respective sets of k-space lines, or from an earlier dynamic.

Abstract: The invention relates to a method of MR imaging near metal parts using SEMAC. It is an object of the invention to provide an improved MR imaging technique that is sufficiently fast and robust against susceptibility effects. The invention proposes to apply a weaker slice-selection magnetic field gradient (Gslice) for reduction of ripple-artefacts near metal parts or to apply undersampling in the slice-selection direction of the SEMAC sequence or to apply both these aspects. According to one aspect of the invention, a sparsity constraint is used to make the reconstruction of the undersampled MR images more stable. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).

Abstract: A parallel magnetic resonance imaging system (1) includes at least one radio frequency (RF) coil (10, 12) with a plurality of coil elements, a smart select unit (24), a parallel imaging parameter unit (28), and a sequence control (16). The smart select unit (24), from a pre-scan or prior scan of a subject with the at least one RF coil, constructs (60) a signal map and a plurality of noise maps based on different sets of reduction factors. The parallel imaging parameter unit (28) selects a set of reduction factors corresponding to a noise map which includes a highest signal-to-noise ratio (SNR). The sequence control (16) performs a magnetic resonance imaging scan of the subject based on the selected reduction factors.

Abstract: In an EPI acquisition sequence for magnetic resonance signals k-space is scanned along sets of lines in k-space along opposite propagation directions, e.g. odd and even lines in k-space. Phase errors that occur due to the opposite propagation directions are corrected for in a SENSE-type parallel imaging reconstruction. The phase error distribution in image space may be initially estimated, calculated form the phase difference between images reconstructed from magnetic resonance signals acquired from the respective sets of k-space lines, or from an earlier dynamic.

Abstract: The invention provides for a magnetic resonance imaging system (300, 400) for acquiring magnetic resonance data (342) from an imaging zone (308). The magnetic resonance imaging system comprises a processor (330) for controlling the magnetic resonance imaging system.

Abstract: A parallel magnetic resonance imaging system (1) includes at least one radio frequency (RF) coil (10, 12) with a plurality of coil elements, a smart select unit (24), a parallel imaging parameter unit (28), and a sequence control (16). The smart select unit (24), from a pre-scan or prior scan of a subject with the at least one RF coil, constructs (60) a signal map and a plurality of noise maps based on different sets of reduction factors. The parallel imaging parameter unit (28) selects a set of reduction factors corresponding to a noise map which includes a highest signal-to-noise ratio (SNR). The sequence control (16) performs a magnetic resonance imaging scan of the subject based on the selected reduction factors.

Abstract: The invention relates to a method of MR imaging near metal parts using SEMAC. It is an object of the invention to provide an improved MR imaging technique that is sufficiently fast and robust against susceptibility effects. The invention proposes to apply a weaker slice-selection magnetic field gradient (Gslice) for reduction of ripple-artefacts near metal parts or to apply undersampling in the slice-selection direction of the SEMAC sequence or to apply both these aspects. According to one aspect of the invention, a sparsity constraint is used to make the reconstruction of the undersampled MR images more stable. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).

Abstract: The invention relates to a method of MR imaging of at least a portion of a body (10) of a patient placed in an examination volume of an MR device (1). The object of the invention is to provide an improved, i.e. faster, parallel imaging technique. The invention proposes to acquire a survey signal data set (21, 22) at a low image resolution, which survey signal data set (21, 22) includes MR signals received in parallel or successively via a volume RF coil (9) and via a set of array RF coils (11, 12, 13). Spatial sensitivity profiles (23) of the array RF coils (11, 12, 13) are determined from the low resolution data. As a next step, a reference scan is performed in which a reference signal data set (25) is acquired at intermediate resolution solely via the array RF coils (11, 12, 13). The spatial sensitivity profiles (27) of the array RF coils (11, 12, 13) are determined from the data acquired at intermediate resolution and from the spatial sensitivity profiles (23) determined before at low resolution.

Abstract: The invention relates to a method of selecting a set of coil elements from a multitude of physical coil elements comprised in a coil array for performing a magnetic resonance imaging scan of a region of interest.

Abstract: The invention relates to a method of MR imaging of at least a portion of a body (10) of a patient placed in an examination volume of an MR device (1). The object of the invention is to provide an improved, i.e. faster, parallel imaging technique. The invention proposes to acquire a survey signal data set (21, 22) at a low image resolution, which survey signal data set (21, 22) includes MR signals received in parallel or successively via a volume RF coil (9) and via a set of array RF coils (11, 12, 13). Spatial sensitivity profiles (23) of the array RF coils (11, 12, 13) are determined from the low resolution data. As a next step, a reference scan is performed in which a reference signal data set (25) is acquired at intermediate resolution solely via the array RF coils (11, 12, 13). The spatial sensitivity profiles (27) of the array RF coils (11, 12, 13) are determined from the data acquired at intermediate resolution and from the spatial sensitivity profiles (23) determined before at low resolution.

Abstract: The invention relates to a method of selecting a set of coil elements from a multitude of physical coil elements comprised in a coil array for performing a magnetic resonance imaging scan of a region of interest.

Abstract: The invention relates to a device (1) for magnetic resonance imaging of a body (7) placed in a stationary and substantially homogeneous main magnetic field. In order to provide an MR device (1) which is arranged to automatically select an optimum subsampling scheme for three-dimensional SENSE, the invention proposes to select the subsampling scheme such that the maximum number of folded-over image values is minimized and simultaneously distances between the positions of the folded-over image values within the predetermined field of view are maximized.

Abstract: The invention relates to a device (1) for magnetic resonance imaging of a body (7) placed in a stationary and substantially homogeneous main magnetic field. In order to provide an MR device (1) which is arranged to automatically select an optimum subsampling scheme for three-dimensional SENSE, the invention proposes to select the subsampling scheme such that the maximum number of folded-over image values is minimized and simultaneously distances between the positions of the folded-over image values within the predetermined field of view are maximized.

Abstract: A magnetic resonance imaging method employs sub-sampled signal acquisition from a number of receiver coils such as surface coils. A full field-of-view magnetic resonance image is reconstructed on the basis of the sensitivity profiles of the receiver coils, for example on the basis of the SENSE technique. The reconstruction is carried out mathematically as an optimization, for example, requiring a minimum noise level in the magnetic resonance image. According to the invention, a priori information is also involved in the reconstruction and the a priori information is taken into account especially as a constraint in optimization.

Abstract: A magnetic resonance imaging method employs sub-sampled signal acquisition from a number of receiver coils such as surface coils. A full field-of-view magnetic resonance image is reconstructed on the basis of the sensitivity profiles of the receiver coils, for example on the basis of the SENSE technique. The reconstruction is carried out mathematically as an optimization, for example, requiring a minimum noise level in the magnetic resonance image. According to the invention, a priori information is also involved in the reconstruction and the a priori information is taken into account especially as a constraint in said optimization.