Abstract: Disclosed herein is a medical system (100, 300). The execution of machine executable instructions (120) causes a processor (104) to: receive (200) measured gradient echo k-space data (122); receive (202) an off-resonance phase map (124); reconstruct (204) an initial image (126) from the measured gradient echo k-space data; calculate (206) an upsampled phase map (128) from the off-resonance phase map; calculate (208) an upsampled image (130) from the initial image; calculating (210) a modulated image (132) by modulating the upsampled image with the upsampled phase map; calculate (212) a corrected image (134) comprising iteratively. The iterative calculation comprises: calculating (214) updated k-space data by applying a data consistency algorithm (138) to a k-space representation of the modulated image and the measured gradient echo k-space data and calculating (216) an updated image (142) from the updated k-space data.

Abstract: A wireless passive marker device (1) to be tracked and a respective tracking system (3) are provided which make use of a sensing unit (10) comprising a resonator element (11) with piezoelectric properties and a coil element (13), whereby an externally applied excitation field having a particular frequency is applied to act on the sensing unit (10) and wherein the sensing unit (10) responds to the externally applied excitation field by the resonator element (11) performing persisting mechanical oscillations in resonant mode, the persisting mechanical oscillations resulting in a piezoelectric voltage causing the coil element (13) to generate a magnetic field that may then be detected by the tracking system (3) and used for determining the position of the marker device (1) and/or sensing a physical property in the surrounding environment of the marker device (1).

Abstract: Disclosed herein is a medical system (100, 300, 400) comprising a memory (110) storing a trainable machine learning module (122) trained using training data descriptive of a training data distribution (600) to output a reconstructed medical image (136) in response to receiving measured medical image data (128) as input. The medical system comprises a computational system (104). The execution of machine executable instructions (120) causes the computational system to: receive (200) the measured medical image data and determine (202) the out-of-distribution score and the in-distribution accuracy score consecutively in an order determined a sequence, detect (204) a rejection of the measured medical image data using the out-of-distribution score and/or the in-distribution accuracy score during execution of the sequence, provide (206) a warning signal (134) if the rejection of the measured medical image data is detected.

Abstract: A method of setting an RF operating frequency of an MRI system (1) uses a first reference frequency signal, obtained from a geo-satellite positioning system, as a stable long term frequency reference. A second frequency source (24) is calibrated using the first frequency reference signal and the second frequency reference source (24) is then used as the master clock for the MRI system (1), for setting the RF operating frequency.

Abstract: For delivering an image-guided radiation therapy treatment to a moving structure included in a region of a patient body a series of first images of the region of the patient body in different phases of a motion of the structure is acquired in accordance with a first imaging mode. The series of first images is associated with a series of second images of the patient body in essentially the same phases of the motion of the target structure, the second images being acquired in a second imaging mode. During the treatment, a third image is acquired using the second imaging mode during the radiation therapy treatment and a continuation of the radiation therapy treatment is planned on the basis of data relating to one of the first images selected on the basis of a comparison between the third image and the second images associated with the first images.

Abstract: A system (100) and computer-implemented method are provided for data collection for distributed machine learning of a machine learnable model. A privacy policy data (050) is provided defining computer-readable criteria for limiting a selection of medical image data (030) to a subset of the medical image data to obfuscate an identity of the at least one patient. The medical image data is selected based on the computer-readable criteria to obtain privacy policy-compliant training data (060) for transmission to another entity. The system and method enable medical data collection at clinical sites without requiring manual oversight, and enables such selections to be made automatically, e.g., based on a request for medical image data which may be received from outside of the clinical site.

Abstract: The invention provides for a magnetic resonance imaging system (100, 200) comprising a memory (148) for storing machine executable instructions (150) and pulse sequence commands (152). The pulse sequence commands are configured for acquiring a four dimensional magnetic resonance data set (162) from an imaging region of interest (109). The four dimensional magnetic resonance data set is at least divided into three dimensional data magnetic resonance data sets (400, 402, 404, 406, 408) indexed by a repetitive motion phase of the subject. The three dimensional data magnetic resonance data sets are further at least divided into and indexed by k-space portions (410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430, 432, 434, 436). The magnetic resonance imaging system further comprises a processor (144) for controlling the magnetic resonance imaging system.

Abstract: Disclosed herein is a medical system (100, 300). The execution of machine executable instructions (120) causes a processor (104) to: receive (200) measured gradient echo k-space data (122); receive (202) an off-resonance phase map (124); reconstruct (204) an initial image (126) from the measured gradient echo k-space data; calculate (206) an upsampled phase map (128) from the off-resonance phase map; calculate (208) an upsampled image (130) from the initial image; calculating (210) a modulated image (132) by modulating the upsampled image with the upsampled phase map; calculate (212) a corrected image (134) comprising iteratively. The iterative calculation comprises: calculating (214) updated k-space data by applying a data consistency algorithm (138) to a k-space representation of the modulated image and the measured gradient echo k-space data and calculating (216) an updated image (142) from the updated k-space data.

Abstract: The invention relates to a method of MR imaging of an object (10). It is an object of the invention to enable MR imaging in the presence of motion of the imaged object, wherein full use is made of the acquired MR signal and a high-quality MR image essentially free from motion artefacts is obtained. The method of the invention comprises the steps of: generating MR signals by subjecting the object (10) to an imaging sequence comprising RF pulses and switched magnetic field gradients; acquiring the MR signals as signal data over a given period of time (T); subdividing the period of time into a number of successive time segments (SO, S1, S2, . . . Sn); deriving a geometric transformation (DVF1, DVF2, . . . DVFn) in image space for each pair of consecutive time segments (S0, S1, S2, . . . Sn), which geometric transformation (DVF1, DVF2, . . .

Abstract: A system for receiving signals from a magneto-mechanical oscillator includes a main coil array adapted to receive a response signal of the magneto-mechanical oscillator and to transmit an excitation signal to the magneto-mechanical oscillator, and an additional coil for receiving a signal of the magneto-mechanical oscillator. A localizer is adapted to localize the additional coil and comprises a controller for controlling the main coil array and the additional coil such that a received localization signal is generated, a sensitivity provider for providing sensitivity information, and a processor for determining a position and/or orientation of the additional coil based on the provided sensitivity information and based on the received localization signal. A kit is provided for upgrading a system with a main coil array, by adding one or more additional coils and providing software for locating the one or more additional coils with the use of a pilot tone transmission.

Abstract: The present invention is directed to a magnetic resonance imaging system with motion detection for examination of a patient (53), the magnetic resonance imaging system comprising an RF coil arrangement with an RF coil (4) for transmitting and/or receiving an RF signal for generating a magnetic resonance image wherein the RF coil arrangement is provided with an additional RF sensor (5) for transmitting an RF transmit signal which is adapted for interacting with the tissue (23) of the patient (53) allowing to sense motion signals due to motions of the patient (53) simultaneously to transmitting and/or receiving the RF signal for generating the magnetic resonance image. In this way movements of a patient under examination in an MRI system may be detected in an efficient and reliable way.

Abstract: The invention relates to a method of MR imaging of an object (10). It is an object of the invention to enable MR imaging in the presence of motion of the imaged object, wherein full use is made of the acquired MR signal and a high-quality MR image essentially free from motion artefacts is obtained. The method of the invention comprises the steps of: generating MR signals by subjecting the object (10) to an imaging sequence comprising RF pulses and switched magnetic field gradients; acquiring the MR signals as signal data over a given period of time (T); subdividing the period of time into a number of successive time segments (SO, S1, S2, . . . Sn); deriving a geometric transformation (DVF1, DVF2, . . . DVFn) in image space for each pair of consecutive time segments (S0, S1, S2, . . . Sn), which geometric transformation (DVF1, DVF2, . . .

Abstract: The invention provides for a magnetic resonance imaging system (100, 200) comprising a memory (148) for storing machine executable instructions (150) and pulse sequence commands (152). The pulse sequence commands are configured for acquiring a four dimensional magnetic resonance data set (162) from an imaging region of interest (109). The four dimensional magnetic resonance data set is at least divided into three dimensional data magnetic resonance data sets (400, 402, 404, 406, 408) indexed by a repetitive motion phase of the subject. The three dimensional data magnetic resonance data sets are further at least divided into and indexed by k-space portions (410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430, 432, 434, 436). The magnetic resonance imaging system further comprises a processor (144) for controlling the magnetic resonance imaging system.

Abstract: MR imaging comprising the steps of: subjecting an object (10) to an imaging sequence of RF pulses and switched magnetic field gradients (GS, GP, GM), which imaging sequence is a steady state sequence comprising a plurality of repeatedly applied acquisition blocks (21), wherein each acquisition block (21) comprises two units (22, 23) in immediate succession, namely: i) a first unit (22) starting with an excitation RF pulse radiated toward the object (10), with the duration of the first unit being an integer multiple of a given time interval T, and ii) a second unit (23) starting with a refocusing RF pulse radiated toward the object (10) and comprising a readout magnetic field gradient (GM) and a phase encoding magnetic field gradient (GP), with the duration of the second unit (23) being an integer multiple of the time interval T, acquiring one or more phase-encoded spin echo signals (31, 32) in a sequence of acquisition blocks (21), and reconstructing one or more MR images from the acquired spin echo signals (

Abstract: An iterative reconstruction is performed of multiple gradient echo MR imaging data to generate a reconstructed MR image (36). The iterative reconstruction uses a model (30) that links the MR imaging data and the reconstructed MR image. The model includes a parameterized magnetic field fluctuation component (32). During the performing of the iterative reconstruction, parameters of the parameterized magnetic field fluctuation component of the model are updated to optimize a cost function (40) dependent on partial derivatives of the reconstructed MR image with respect to the parameters of the parameterized magnetic field fluctuation component of the model. The image may be further processed to generate an R2* map (50), an SWI image (52), or a QSM map (54).

Abstract: The invention provides for an MRI system (100) with an RF system for acquiring magnetic resonance data (142). The RF system comprises a set of antenna elements (126). The MRI system (100) further comprises a processor for controlling the MRI system (100). Magnetic resonance data is acquired. Combined image data (144) is reconstructed. The reconstruction comprises transforming the acquired magnetic resonance data (142) from k-space to image space and combining the resulting image data. For each antenna element (126) magnetic resonance data (146) is simulated using the reconstructed combined image data (144). The simulation comprises transforming the reconstructed combined image data (144) from image space to k-space. A phase correction factor is determined, The determination comprises calculating phase differences between the acquired magnetic resonance data (142) and the simulated magnetic resonance data (146). The acquired magnetic resonance data (142) is corrected using the phase correction factor.

Abstract: The invention provides for a medical instrument (100, 300, 400, 500) comprising a magnetic resonance imaging system (102). The medical instrument further comprises a subject support (120) with a support surface (121) configured for supporting at least a portion of the subject within an imaging zone (108). The subject support comprises a radar array (125) embedded below the support surface. The medical instrument further comprises a radar system (124) for acquiring a radar signal (144) from the subject. The medical instrument further comprises a motion detection system (122) configured for acquiring a movement signal (146).

Abstract: A magnetic resonance imaging system connectable to a respiration monitor configured to provide an output signal whose level represents a respiration state. A prospective acquisition scheme for acquiring magnetic resonance images at each of a set of selected respiration states is provided, the triggering on the selected respiration states being based on predetermined threshold output signal levels of the respiration monitoring means, Respiration states at which magnetic resonance images were actually acquired, are compared with the selected respiration states according to the prospective acquisition scheme and predetermined ranges of tolerance of the selected respiration states, The prospective acquisition scheme is modified, if one of the actual respiration states lies outside the predetermined range of tolerance of the selected respiration state, and magnetic resonance imaging acquisition is executed pursuant to the modified prospective acquisition scheme.

Abstract: A magnetic resonance imaging (MRI) system (100, 600) that generates information indicative of a fluid flow in accordance with a pseudo-continuous arterial spin labeling (pCASL) method. The MRI system may include at least one controller (104, 610) configured to generate a pseudo-continuous arterial spin labeling (pCASL) pulse sequence (200) including at least a first gradient (GR) pulse sequence (207) having a sinusoidal waveform including a plurality of cycles, and a second radio frequency (RF) pulse sequence (205) including a half-wave rectified sinusoidal waveform having a plurality of cycles and which is synchronous with the first GR pulse sequence; label at least part of the fluid flow in a labeling region during a labeling mode using the pCASL pulse sequence; acquire label and control image information of the fluid flow at an imaging region proximal to downstream of the labeling region; and/or generate image information in accordance with a difference of the acquired label and control image information.

Abstract: A medical instrument includes a magnetic resonance (MR) imaging system with an imaging zone and a gradient coil system with three orthogonal gradient coils. A processor controls the medical instrument to: repeatedly control the MR imaging system with calibration pulse sequence commands to acquire the MR calibration data for multiples slices using at least one of the three orthogonal gradient coils to generate the slice select gradient magnetic field; compute a Fourier transform of the MR calibration data for each of the voxels of the multiple slices in the phase encoding directions; compute an expansion of the Fourier transformed MR calibration data into spherical harmonics; and calculate a three-dimensional gradient impulse response function for the at least one of the three orthogonal gradient coils using the expansion into spherical harmonics.