Abstract: The invention provides for a magnetic resonance imaging system (100) which comprise a magnet (104) and a magnetic field gradient generator (110, 112) for generating a gradient magnetic field within an imaging zone (108). The gradient magnetic field is aligned with a predetermined direction. The magnetic resonance imaging system further comprise a memory (134, 136) for storing machine executable instructions (150, 152, 154), a pre-calculated magnetic resonance fingerprinting dictionary (144), and pulse sequence instructions (140). The pulse sequence instructions cause the magnetic resonance imaging system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The magnetic resonance fingerprinting technique encodes the magnetic resonance data as slices (125).

Abstract: A magnetic resonance imaging system (100) acquires magnetic resonance data (142, 148, 158) with a pulse sequence (140) for multiple slice acquisition performed over multiple repetition cycles. The magnetic resonance imaging system includes a processor (540) configured to: acquire (200) a first slice group (142) of the magnetic resonance data during a first repetition cycle; extract (202) first central k-space data (144) from the first slice group; reconstruct (204) first navigator data (146) using the first central k-space data.

Abstract: The invention provides for a magnetic resonance imaging system (100) for acquiring magnetic resonance data (142) from a subject (118) within a measurement zone (108), wherein the magnetic resonance imaging system comprises: a processor (130) for controlling the magnetic resonance imaging system and a memory (136) for storing machine executable instructions (150, 152, 154) and pulse sequence commands (140). The pulse sequence commands for controlling the magnetic resonance imaging system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting protocol. The pulse sequence commands are configured for controlling the magnetic resonance imaging system to generate an RF pulse train (300). The pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire the magnetic resonance data as multiple k-space traces.

Abstract: A magnetic resonance imaging system (200, 300) acquires magnetic resonance data (242, 244). A processor (230) controls the magnetic resonance imaging system to execute instructions (250, 252, 254, 256, 258) which cause the processor to repeatedly: control (100) the magnetic resonance imaging system to acquire magnetic resonance data including magnetic resonance navigator data (244); create (102) a set of navigator vectors by extracting the navigator data from each portion of the magnetic resonance data; construct (104) a dissimilarity matrix (246, 400, 700, 800, 900, 1000, 1100, 1400, 1500) by calculating a metric between each of the set of navigator vectors; generate (106) a matrix classification (248) of the dissimilarity matrix using a classification algorithm; and control (108) the magnetic resonance imaging system to modify acquisition of the magnetic resonance data using the matrix classification.

Abstract: A method of MR imaging, wherein a portion of a body placed in the examination volume of a MR device is subjected to an imaging sequence of RF pulses and switched magnetic field gradients. The imaging sequence is a stimulated echo sequence including i) at least two preparation RF pulses (?) radiated toward the portion of the body during a preparation period, and ii) one or more reading RF pulses (?) radiated toward the portion of the body during an acquisition period temporally subsequent to the preparation period. One or more FID signals and one or more stimulated echo signals are acquired during the acquisition period. A B1 map indicating the spatial distribution of the RF field of the RF pulses within the portion of the body is derived from the acquired FID and stimulated echo signals.

Abstract: The invention provides for a magnetic resonance imaging system (100, 300) comprising: a radio-frequency system (116, 122, 124, 126, 126?, 126?, 126??) for acquiring magnetic resonance data (152) from an imaging zone (108), wherein the radio-frequency system comprises multiple antenna elements (126, 126?, 126?, 126??); a memory (140) containing machine executable instructions (170) and pulse sequence commands (150), wherein the pulse sequence commands cause the processor to acquire magnetic resonance data from the multiple antenna elements according to a SENSE protocol; and a processor.

Abstract: A magnetic resonance imaging system acquires magnetic resonance data from a target volume in a subject. The magnetic resonance imaging system includes multiple excitation sources for generating a slice-selective or slab-selective spatial radio frequency (RF) excitation magnetic field targeting slice/slab spatial variations in the target volume, and a controller coupled to the excitation sources. The controller is adapted for: determining a power level required by the excitation sources for generating the slice-selective/or slab-selective spatial RF excitation magnetic field, decomposing the slice-selective or slab-selective spatial RF excitation magnetic field into respective RF excitation constituents of the excitation sources, controlling each of the excitation sources to simultaneously generate the respective RF excitation constituent, using the determined power level for acquiring the magnetic resonance data.

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: A magnetic resonance imaging method includes acquisition of datasets of magnetic resonance data from an object. At least some of the datasets are undersampled in k-space. Each dataset relating to a motion state of the object. Images are reconstructed from each of the datasets by way of a compressed sensing reconstruction. Motion correction is applied to the reconstructed images relative to a selected motion state, so as to generate motion corrected images. A diagnostic image for the selected motion state is derived, e.g. by averaging from the motion corrected images.

Abstract: The invention provides for a method of operating an instrument (100). The instrument comprises a magnetic resonance system (102) for measuring dictionary magnetic resonance data (154) from a measurement zone (108). The magnetic resonance system comprises a magnet (104) for generating a main magnetic field within the measurement zone. The magnetic resonance system comprises a test fixture (124) for holding a test sample (132) within the measurement zone. The test fixture comprises a supplementary magnetic field coil (126) and a magnetic resonance antenna (128).

Abstract: The invention provides for a medical instrument (100, 500) comprising a magnetic resonance imaging system (102) for acquiring magnetic resonance data (142) from a subject (118) within an imaging zone (108). The magnetic resonance imaging system comprises: a main magnet (104) for generating a B0 magnetic field within the imaging zone; a memory (134, 136) containing machine executable instructions (160, 162, 164, 166) and pulse sequence commands (140); a processor (130) for controlling the medical instrument.

Abstract: The invention relates to a method of parallel MR imaging, wherein a reference scan is performed by means of a stimulated echo sequence including i) at least two preparation RF pulses (?) radiated toward a portion of a body (10) during a preparation period (21), and ii) one or more reading RF pulses (?) radiated toward the portion of the body (10) during an acquisition period (22) temporally subsequent to the preparation period (21). One or more FID signals (I1) and one or more stimulated echo signals (I2) are acquired during the acquisition period (22). The spatial receive and/or—if applicable—transmit4 sensitivity profiles of at least two RF coils (11, 12, 13) are derived from the acquired FID signals (I1) and/or from the acquired stimulated echo signals (I2). The parameters of the stimulated echo sequence are selected such that it is robust against susceptibility-induced artifacts. Moreover, 10 the invention relates to a MR device (1) and to a computer program for a MR device (1).

Abstract: In an MR imaging method and apparatus, a portion of a body placed in an examination volume of an MR device is subjected to an imaging sequence of RF pulses and switched magnetic field gradients. The imaging sequence is a stimulated echo sequence including i) two preparation RF pulses (?) radiated toward the portion of the body during a preparation period (21), and ii) reading RF pulses (?) radiated toward the portion of the body during an acquisition period (22) temporally subsequent to the preparation period (21). FID signals (I1) and stimulated echo signals (I2) are acquired during the acquisition period (22) with equal T2*-weighting. A B1 map indicating a spatial distribution of the RF field of the preparation RF pulses within the portion of the body is derived from the acquired FID (I1) and stimulated echo (I2) signals.

Abstract: The invention relates to a method of MR imaging of an object (10). The problem of the invention is to provide an improved MR imaging technique that enables fast and robust determination of spatial sensitivity profiles of RF receiving antennas (11, 12, 13) used in parallel imaging as well as B1 and/or B0 mapping. The method of the invention comprises subjecting the object (10) to a stimulated echo sequence. Two or more stimulated echo signals (STE, STE*) are acquired, namely a direct stimulated echo signal (STE) and a conjugated stimulated echo signal (STE*), wherein at least one of the stimulated echo signals (STE, STE*) is received in parallel via an array of two or more RF receiving antennas (11, 12, 13) having different spatial sensitivity profiles, and wherein at least another one of the stimulated echo signals (STE, STE*)is received via a body RF coil (9) having an essentially homogeneous spatial sensitivity profile.

Abstract: The invention provides for a magnetic resonance system (100) comprising a magnet (104) for generating a main magnetic field within the measurement zone and a magnetic field gradient system (110, 112) for generating a gradient magnetic field within the measurement zone in at least one direction by supplying current to a set of magnetic gradient coils (112) for each of the at least one direction. Instructions cause a a processor (130) controlling the magnetic resonance system, wherein execution of the machine executable instructions causes the processor to acquire (200) the magnetic resonance data by controlling the magnetic resonance system with pulse sequence commands. The pulse sequence commands (140) cause the magnetic resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The pulse sequence commands specify a train (500) of pulse sequence repetitions (502, 504), each with a fixed repetition time (302).

Abstract: The invention provides for a method of operating a magnetic resonance system for acquiring magnetic resonance data (152) from a phantom (124) within a measurement (zone 108). The phantom comprises a known volume of at least one predetermined substance ((128), 130). The method comprises the step of acquiring (300) the magnetic resonance data by controlling the magnetic resonance system with pulse sequence instructions (150). The pulse sequence instructions cause the magnetic resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The pulse sequence instructions specify a train of pulse sequence repetitions. Each pulse sequence repetition has a repetition time chosen from a distribution of repetition times. Each pulse sequence repetition comprises a radio frequency pulse chosen from a distribution of radio frequency pulses. The distribution of radio frequency pulses cause magnetic spins to rotate to a distribution of flip angles.

Abstract: The invention provides for a magnetic resonance imaging system (100, 300, 100) for acquiring magnetic resonance data (110, 1104) from a subject (118) within an imaging zone (108). The magnetic resonance imaging system comprises a memory (136) for storing machine executable instructions (160, 162, 164, 166, 316) and pulse sequence data (140, 1102). The pulse sequence data comprises instructions for controlling the magnetic resonance imaging system to acquire magnetic resonance data according to a magnetic resonance imaging method. The magnetic resonance imaging system further comprises a processor (130) for controlling the magnetic resonance imaging system.

Abstract: A method of employing a central computer database (18) for supporting a characterization of tissue by magnetic resonance fingerprinting measurements, including steps of —exciting nuclei of a subject of interest by applying (50) a radio frequency excitation field B1 generated according to a magnetic resonance fingerprinting sequence (38), —acquiring (52) magnetic resonance imaging signal data from radiation emitted by excited nuclei of the subject of interest, —transferring (54) a magnetic resonance fingerprinting data set (42) to the central computer database (18), —retrieving (56) a predefined dictionary from the central computer database (18), —matching (60) the acquired magnetic resonance imaging signal data to the retrieved dictionary by applying a pattern recognition algorithm to determine a value (40) or a set of values (40) for at least one physical quantity (T1, T2), —adding (62) at least the determined value (40) or the determined set of values (40) as a new entry of an associated medical data set (3

Abstract: The invention provides for a magnetic resonance imaging system (100) which comprise a magnet (104) and a magnetic field gradient generator (110, 112) for generating a gradient magnetic field within an imaging zone (108). The gradient magnetic field is aligned with a predetermined direction. The magnetic resonance imaging system further comprise a memory (134, 136) for storing machine executable instructions (150, 152, 154), a pre-calculated magnetic resonance fingerprinting dictionary (144), and pulse sequence instructions (140). The pulse sequence instructions cause the magnetic resonance imaging system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The magnetic resonance fingerprinting technique encodes the magnetic resonance data as slices (125).

Abstract: The invention provides for a magnetic resonance system (100) for acquiring a magnetic resonance data from a subject (118) within a measurement zone (108) according to a magnetic resonance fingerprinting technique. The pulse sequence comprises a train of pulse sequence repetitions (302, 304). Each pulse sequence repetition has a repetition time chosen from a distribution of repetition times. Each pulse sequence repetition comprises a radio frequency pulse (306) chosen from a distribution of radio frequency pulses. The distribution of radio frequency pulses cause magnetic spins to rotate to a distribution of flip angles, and each pulse sequence repetition comprises a sampling event (310) at a sampling time chosen from a distribution of sampling times. Each pulse sequence repetition of the pulse sequence comprises a first 180 degree RF pulse (308) performed at a first temporal midpoint between the radio frequency pulse and the sampling event to refocus the magnetic resonance signal.