Parallel multi-slice MR imaging using phase-modulated RF pulses

    公开(公告)号:US10088543B2

    公开(公告)日:2018-10-02

    申请号:US14774314

    申请日:2014-03-11

    摘要: The invention relates to a method of MR imaging of an object (10) placed in an examination volume of a MR device (1). The method comprises the steps of: —subjecting the object (10) to an imaging sequence comprising phase-modulated multi-slice RF pulses for simultaneously exciting two or more spatially separate image slices, —acquiring MR signals, wherein the MR signals are received in parallel via a set of at least two RF coils (11, 12, 13) having different spatial sensitivity profiles within the examination volume, and —reconstructing a MR image for each image slice from the acquired MR signals, wherein MR signal contributions from the different image slices are separated on the basis of the spatial sensitivity profiles of the at least two RF coils (11, 12, 13) and on the basis of the phase modulation scheme of the RF pulses. In order to optimize the conditioning of the inverse problem of the MR image reconstruction, the phase-modulation scheme of the RF pulses is derived from the spatial sensitivity profiles of the at least two RF coils (11, 12, 13). Moreover, the invention relates to a MR device for carrying out this method as well as to a computer program to be run on a MR device.

    Multi-state magnetic resonance fingerprinting

    公开(公告)号:US11579230B2

    公开(公告)日:2023-02-14

    申请号:US16468849

    申请日:2017-12-06

    摘要: 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). The magnetic resonance imaging system (100) comprises: a processor (130) for controlling the magnetic resonance imaging system (100) and a memory (136) storing machine executable instructions (150, 152, 154), pulse sequence commands (140) and a dictionary (144). The pulse sequence commands (140) are configured for controlling the magnetic resonance imaging system (100) to acquire the magnetic resonance data (142) of multiple steady state free precession (SSFP) states per repetition time. The pulse sequence commands (140) are further configured for controlling the magnetic resonance imaging system (100) to acquire the magnetic resonance data (142) of the multiple steady state free precession (SSFP) states according to a magnetic resonance fingerprinting protocol. The dictionary (144) comprises a plurality of tissue parameter sets. Each tissue parameter set is assigned with signal evolution data pre-calculated for multiple SSFP states.

    Selection of magnetic resonance fingerprinting dictionaries for anatomical regions

    公开(公告)号:US11112478B2

    公开(公告)日:2021-09-07

    申请号:US16497480

    申请日:2018-03-30

    摘要: The invention provides for a magnetic resonance imaging system (100) for acquiring MRF magnetic resonance data (144) from a subject (118) within a region of interest (109). The magnetic resonance imaging system comprises a processor (130) for controlling the magnetic resonance imaging system and a memory (134) for storing machine executable instructions (140) and MRF pulse sequence commands (142). The MRF pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire the MRF magnetic resonance data according to a magnetic resonance fingerprinting protocol. Execution of the machine executable instructions causes the processor to: acquire (200) the MRF magnetic resonance data for the region of interest by controlling the magnetic resonance imaging system with the MRF pulse sequence commands; receive (202) at least one magnetic resonance image (152) descriptive of the region of interest; identify (204) anatomical regions (156) within the region of interest using an anatomical model (154); select (206) a local magnetic resonance fingerprinting dictionary (158) from a set of magnetic resonance fingerprinting dictionaries for each of the anatomical regions, wherein the local magnetic resonance fingerprinting dictionary comprises a listing of calculated MRF signals for a set of predetermined substances specific to each of the anatomical regions; and calculate (208) a composition mapping (160) of the predetermined substances for each of the anatomical regions using the MRF magnetic resonance data and the local magnetic resonance fingerprinting dictionary, wherein the composition mapping is a spatial average within each of the anatomical regions.

    Silent 3D magnetic resonance fingerprinting

    公开(公告)号:US10816625B2

    公开(公告)日:2020-10-27

    申请号:US16095954

    申请日:2017-04-26

    摘要: The invention provides for a magnetic resonance imaging system (100) for acquiring magnetic resonance data (142) from a subject (118) within an imaging zone (108). The magnetic resonance imaging system comprises a memory (134, 136) for storing machine executable instructions (160), and pulse sequence commands (140, 400, 502, 600, 700), wherein the pulse sequence commands are configured to cause the magnetic imaging resonance system to acquire the magnetic resonance data according to a magnetic resonance fingerprinting technique. The pulse sequence commands are further configured to control the magnetic resonance imaging system to perform spatial encoding using a zero echo time magnetic resonance imaging protocol. Execution of the machine executable instructions causes the processor controlling the MRI system to: acquire (200) the magnetic resonance data by controlling the magnetic resonance imaging system with the pulse sequence commands; and calculate (202) a spatial distribution (146) of each of a set of predetermined substances by comparing the magnetic resonance data with a magnetic resonance fingerprinting dictionary (144).

    MAGNETIC RESONANCE FINGERPRINTING IN FOURIER SPACE

    公开(公告)号:US20200166596A1

    公开(公告)日:2020-05-28

    申请号:US16627827

    申请日:2018-07-03

    摘要: The invention relates to a magnetic resonance imaging system (100, 400) comprising a memory (134) for storing machine executable instructions (140) and MRF pulse sequence commands (142). The MRF pulse sequence commands are configured for controlling the magnetic resonance imaging system to acquire MRF magnetic resonance data (144) according to a magnetic resonance fingerprinting protocol. The memory further contains a Fourier transformed magnetic resonance finger printing dictionary (150). The Fourier transformed magnetic resonance finger printing dictionary comprises entries for at least one intrinsic property (152). The magnetic resonance imaging system further comprises a processor (130) for controlling the magnetic resonance imaging system. Execution of the machine executable instructions causes the processor to: acquire (200) MRF magnetic resonance data (144) descriptive of a region of interest (109) by controlling the magnetic resonance imaging system with the MRF pulse sequence commands, wherein the region of interest is divided into voxels; construct (202) an MRF signal (146) for each of the voxels using the MRF magnetic resonance data; construct (204) a Fourier transformed MRF signal (148) by Fourier transforming the MRF signal for each of the voxels; and determine (206) the least one intrinsic property for each of the voxels using the Fourier transformed MRF signal and the Fourier transformed magnetic resonance finger printing dictionary. The Fourier transformed MRF signal is truncated to a predetermined number of terms before determining the at least one intrinsic property.

    MR fingerprinting for determining performance degradation of the MR system

    公开(公告)号:US10345407B2

    公开(公告)日:2019-07-09

    申请号:US15547622

    申请日:2016-01-22

    摘要: 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. Each pulse sequence repetition comprises a sampling event where the magnetic resonance signal is sampled for a predetermined duration at a sampling time before the end of the pulse sequence repetition. The method further comprises determining (302) one or more performance degradation conditions of the magnetic resonance system by comparing the magnetic resonance data with a magnetic resonance fingerprinting dictionary (154). The magnetic resonance fingerprinting dictionary contains a listing of magnetic resonance signals for a set of system states in response to execution of the pulse sequence instructions for each of the at least one predetermined substance.

    Magnetic resonance fingerprinting in slices along a one-dimensional extension

    公开(公告)号:US10321845B2

    公开(公告)日:2019-06-18

    申请号:US15525145

    申请日:2015-10-30

    摘要: 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). The pre-calculated magnetic resonance fingerprinting dictionary contains a listing of calculated magnetic resonance signals in response to execution of the pulse sequence instructions for a set of predetermined substances. Execution of the machine executable instructions causes a processor (130) controlling the magnetic resonance imaging system to: acquire (300) the magnetic resonance data by controlling the magnetic resonance imaging system with pulse sequence instructions; divide (302) the magnetic resonance data into a set of slices; calculate (304) the abundance of each of the set of predetermined substances within each of the set of slices by comparing the magnetic resonance data for each of the set of slices with the pre-calculated magnetic resonance fingerprinting dictionary; and calculate (306) a magnetic resonance fingerprint chart by plotting abundance of each of the set of predetermined substances within each of the set of slices as a function of position along the predetermined direction.

    Anomaly detection using magnetic resonance fingerprinting

    公开(公告)号:US11435422B2

    公开(公告)日:2022-09-06

    申请号:US17027743

    申请日:2020-09-22

    摘要: The invention provides for a medical imaging system comprising: a memory for storing machine executable instructions; a processor for controlling the medical instrument. Execution of the machine executable instructions causes the processor to: receive MRF magnetic resonance data acquired according to an MRF magnetic resonance imaging protocol of a region of interest; reconstruct an MRF vector for each voxel of a set of voxels descriptive of the region of interest using the MRF magnetic resonance data according to the MRF magnetic resonance imaging protocol; calculate a preprocessed MRF vector (126) for each of the set of voxels by applying a predetermined preprocessing routine to the MRF vector for each voxel, wherein the predetermined preprocessing routine comprises normalizing the preprocessed MRF vector for each voxel; calculate an outlier map for the set of voxels by assigning an outlier score to the preprocessed MRF vector using a machine learning algorithm.