Patent classifications
G01R33/5607
TTField treatment with optimization of electrode positions based on low frequency (<1MHZ) AC conductivity estimates derived from two MRI images having different repetition times
A 3D model of AC electrical conductivity (at a given frequency) of an anatomic volume can be created by obtaining two MRI images of the anatomic volume, where the two images have different repetition times. Then, for each voxel in the anatomic volume, a ratio IR of the intensity of the corresponding voxels in the two MRI images is calculated. This calculated IR is then mapped into a corresponding voxel of a 3D model of AC electrical conductivity at the given frequency. The given frequency is below 1 MHz (e.g., 200 kHz). In some embodiments, the 3D model of AC electrical conductivity at the given frequency is used to determine the positions for the electrodes in TTFields (Tumor Treating Fields) treatment.
MAGNETIC RESONANCE APPARATUS
A magnetic resonance imaging apparatus comprises a scanning unit for performing a pulse sequence PS including a MT (Magnetization Transfer) pulse b for lessening signals from the cerebral parenchyma (white matter and gray matter). The scanning unit performs the pulse sequence PS in periods of time P1 and P3 in the pulse sequence PS so that the MT pulse b is applied every repetition time TR, while it performs the pulse sequence PS in a period of time P2 in the pulse sequence PS so that no MT pulse b is applied.
Background-suppressed myelin water imaging
A technique and associated imaging system is provided that selectively acquires the myelin water signal by utilizing a multiple inversion RF pulses to suppress a range of long T.sub.1 components including those from axonal and extracellular water. This leaves the myelin water, which has been suggested to have short T.sub.1, as the primary source of the image. After long T.sub.1 suppression, the resulting image is dominated by short T.sub.2 in the range of the myelin water (T.sub.2*<20 ms at 3 T). This result confirms that the short T.sub.1 component has short T.sub.2* and, therefore, the resulting image is a myelin water image.
Dynamic B.SUB.0 .shimming for improved fat saturation in magnetic resonance imaging (MRI)
A fat saturation method for a magnetic resonance imaging system having a main magnet providing a magnetic field B.sub.0 The method includes: driving a shim coil assembly with a first set of shimming currents to sufficiently alter a B.sub.0 field inhomogeneity of the magnetic field B.sub.0 within a region that includes a first imaging volume of interest such that water saturation inside the region is reduced from before the first set of shimming currents are applied; applying a fat saturation pulse to the region; identifying the first imaging volume of interest from the region; driving the shim coil assembly with a second set of shimming currents to alter the B.sub.0 field inhomogeneity of the magnetic field B.sub.0 within the first imaging volume of interest such that the B.sub.0 field inhomogeneity within the first imaging volume of interest is reduced; and obtaining magnetic resonance signals from the first imaging volume of interest.
METHOD AND MAGNETIC RESONANCE APPARATUS FOR RECORDING MAGNETIC RESONANCE DATA USING A bSSFP SEQUENCE
In a method and magnetic resonance apparatus for recording magnetic resonance data using a bSSFP sequence, a k-space line to be scanned in k-space is divided into at least two line sections, with at least two of the at least two line sections being scanned separately in different repetitions of the sequence.
SYSTEMS AND METHODS OF DEEP LEARNING FOR LARGE-SCALE DYNAMIC MAGNETIC RESONANCE IMAGE RECONSTRUCTION
A method for performing magnetic resonance imaging on a subject comprises obtaining undersampled imaging data, extracting one or more temporal basis functions from the imaging data, extracting one or more preliminary spatial weighting functions from the imaging data, inputting the one or more preliminary spatial weighting functions into a neural network to produce one or more final spatial weighting functions, and multiplying the one or more final spatial weighting functions by the one or more temporal basis functions to generate an image sequence. Each of the temporal basis functions corresponds to at least one time-varying dimension of the subject. Each of the preliminary spatial weighting functions corresponds to a spatially-varying dimension of the subject. Each of the final spatial weighting functions is an artifact-free estimation of the one of the one or more preliminary spatial weighting functions.
Method and apparatus for magnetic resonance imaging
In a method and apparatus for magnetic resonance imaging, in order to improve saturation of magnetic resonance signals during an acquisition sequence, the acquisition sequence includes at least one acquisition cycle, that includes: a preparation pulse set with a number of preparation pulses, a saturation pulse set that is disjoint from the preparation pulse set, with a number of saturation pulses, and a readout block set with a number of readout blocks. The acquisition cycle is temporally divided into a preparation phase and a readout phase, wherein the readout phase is temporally delimited from the preparation phase, and the readout phase follows the preparation phase in the acquisition cycle, and wherein the preparation phase includes at least one preparation pulse of the preparation pulse set, at least one saturation pulse of the saturation pulse set and no readout block of the readout block set, and the readout phase includes at least one saturation pulse of the saturation pulse set and at least one readout block of the readout block set.
MAGNETIC RESONANCE IMAGING DEVICE, VASCULAR IMAGE GENERATION METHOD, AND RECORDING MEDIUM
A system for acquiring an image in which deterioration of vascular signals due to improved water-fat swap is provided. The system includes a magnetic resonance imaging device, which receives an out-of-phase signal and in-phase signal from an imaging site including a blood vessel. The system also includes a processor that processes a digital signal including data representing the out-of-phase signal and in-phase signal. The processor executes an operation including: generating a water image Wa based on the digital signal; and adding a signal intensity lI.sub.inl of the out-of-phase signal and a signal intensity of the in-phase signal to the water image Wa to generate a vascular image representing the blood vessel.
METHOD FOR AUTOMATICALLY COMPENSATING EDDY CURRENTS IN A MAGNETIC RESONANCE APPARATUS
Methods for automatically compensating eddy currents in a magnetic resonance apparatus include determining modified magnetic resonance sequence data by a compensation computing unit and performing a magnetic resonance measurement in which a gradient generating system generates magnetic field gradients based on the modified magnetic resonance sequence data. The determining of the modified magnetic field gradient includes: receiving original magnetic resonance sequence data of a predetermined magnetic resonance sequence; computing eddy current information about eddy currents that would be produced in the magnetic resonance apparatus by applying the original magnetic resonance sequence data; computing, based on the computed eddy current information, at least one eddy current compensation gradient pulse for compensating the eddy currents; generating modified magnetic resonance sequence data by inserting the at least one eddy current compensation gradient pulse into the original magnetic resonance sequence data; and outputting the modified magnetic resonance sequence data to the gradient generating system.
System and method for estimating a static magnetic field
A method includes applying a preparatory radiofrequency (RF) pulse at a first time instant to a Magnetic Resonance (MR) scanner configured to scan an object comprising a plurality of chemical species. The method further includes applying a phase sensitive pulse sequence at a second time instant to the MR scanner, wherein the preparatory RF pulse and a time delay between the first and the second time instants null a first subset of chemical species from the plurality of chemical species. The method further includes receiving an output signal from a second subset of chemical species from the plurality of chemical species in response to the phase sensitive pulse sequence. The method also includes estimating a static magnetic field map based on the output signal from the second subset of chemical species.