A magnetic resonance control sequence with a pulse arrangement that acts selectively in at least two spatial directions in order to excite a limited rotationally symmetrical excitation profile within an examination subject has an RF excitation pulse formed as a sequence of multiple partial RF pulses, and gradient pulses in the two spatial directions that are coordinated with the partial RF pulses so that the RF energy introduction of different partial RF pulses in transmission k-space occurs on circular k-space transmission trajectories that are concentric to one another. The amplitude of the RF envelope of the partial RF pulses is constant during the duration of a traversal of each circular k-space trajectory. The control sequence can also be used in a calibration of a magnetic resonance system.

A method for determining the spatial distribution of magnetic resonance signals from at least one of N subvolumes predefines a reception encoding scheme and determines unique spatial encoding for at least one of the subvolumes but not for the entire volume under examination (UV). A transmission encoding scheme is also defined, wherein encoding is effected via the amplitude and/or phase of the transverse magnetization. The temporal amplitude and phase profile of the RF pulses is then calculated and each reception encoding step is carried out I times with variations according to the I transmission encoding steps in the transmission encoding scheme. The method makes it possible to largely restrict the spatially resolving MR signal encoding and image reconstruction to subvolumes of the object under examination without the achievable image quality sensitively depending on imperfections in the MR apparatus.

A system and method to detect abnormality of subjects directly from MRI k-space data are provided. The system includes: at least one computer hardware processor, at least one non-transitory computer-readable storage medium, and at least one computer program stored in the at least one non-transitory computer-readable storage medium and executable on the at least one computer hardware processor, wherein the at least one computer program includes: an acquisition module, configured to obtain target MRI k-space data by scanning a subject, wherein the target MRI k-space data are fully-sampled or undersampled or sparse MRI k-space data; a detection module, configured to obtain and output detection outcome from the target MRI k-space data using detection models; and a model training module, configured to train the detection models based on training data. Hence, the MRI scan time and related cost are reduced, and the accuracy of the detecting results is increased.

In order to provide a technique for improving image quality by selectively exciting only a target region with high precision in either of a two-dimensional spatial selective excitation method or a three-dimensional spatial selective excitation method, selecting a k-space trajectory restraining excitation in a non-target region by side lobes is received. At this time, an excitation region of the selected k-space trajectory is presented to an operator, and the operator can adjust the excitation region through the display. After the adjustment of the excitation region by the operator is reflected, a multi-dimensional spatial selective excitation pulse is stabilized.

In a method and magnetic resonance apparatus to continuously correct phase errors in a magnetic resonance measurement sequence in which multiple sequentially radiated, multidimensional, spatially-selective radio-frequency excitation pulses are used, multiple calibration gradient echoes are acquired in a calibration acquisition sequence and a correction value for a phase response and a correction value for a phase difference are calculated from the multiple calibration gradient echoes. Furthermore, an additional radio-frequency excitation pulse is radiated takes into account the correction values.

In a method and magnetic resonance system to correct phase errors in multidimensional, spatially selective radio-frequency excitation pulses in a pulse sequence used to operate the system to acquire magnetic resonance data, a multidimensional, spatially selective radio-frequency excitation pulse is radiated and multiple calibration gradient echoes are acquired. A phase correction and a time correction of the multidimensional, spatially selective radio-frequency excitation pulse is then calculated.

A system and method for rapid acquisition of MRI data at multiple points in time in an. MRI scan using tailored excitation modules, said method comprising the steps of: obtaining tailored signal excitation modules by using RF excitation pulses in combination with one or more magnetic field gradients; acquiring an aliased k-space dataset at a point in time using a pulse sequence that employs said obtained tailored signal excitation modules, which tag and overlap distinct k-space points; repeating steps (a) and (b) for acquiring aliased k-space datasets at multiple time points in a scan while tagging the overlapped, k-space points as a function of time to obtain an accelerated k-t dataset; undoing k-space aliasing m the acquired k-space datasets by Fourier transforming them along the time axis followed by a filtering process to separate the overlapped points; and performing a Fourier transformation along one or more axes, of the un-aliased k-space datasets to generate image frames for the different time points at which data was acquired.

A method for reduced field of view magnetic resonance (MR) imaging includes applying a pulse sequence using a plurality of gradient coils and at least one RF coil of a magnetic resonance imaging system. The pulse sequence includes a two dimensional (2D) echo-planar RF excitation pulse with a plurality of side lobes along a slice select axis and a multiband RF refocusing pulse. MR data is acquired in response to the application of the pulse sequence and at least one MR image is reconstructed based on the MR data. The at least one MR image may then be displayed.

A high-quality image is obtained using a two-dimensional selective excitation method even if the static magnetic field is not uniform. Therefore, non-uniformity of a static magnetic field of a region to be focused in particular in a selective excitation region excited by 2DRF is measured, and a result of the measurement is reflected in an imaging sequence using the 2DRF. For example, a resonance frequency of magnetization obtained from the measurement result is set as an irradiation frequency of the 2DRF. In addition, a shim gradient magnetic field is applied so as to correct the non-uniformity of the magnetization obtained from the measurement result. These are applied only in the imaging sequence using the 2DRF, and an irradiation frequency and a shim gradient magnetic field set in a conventional method are used in other imaging sequences.

In order to generate an RF excitation pulse together with a gradient curve to excite nuclear spins an arbitrarily shaped volume with a magnetic resonance system, a volume segment is prepared in which the volume is situated, such that only spins within the volume yield an MR signal portion in the subsequent detection of an MR signal. An MR signal is detected from the volume segment along a trajectory of k-space. At least one gradient for scanning k-space along the trajectory is switched during the detection. The RF excitation pulse is generated corresponding to the MR signal detected in a temporally inverted manner, and the gradient curve is generated corresponding to the temporally inverted curve of the at least one gradient to scan k-space.