Patent classifications
G01R33/56554
METHOD FOR CORRECTING PHASE OFFSETS IN QUANTITATIVE CHEMICAL SHIFT ENCODED MAGNETIC RESONANCE IMAGING
Systems and methods for correcting phase errors in chemical shift encoded data are described. The technique is self-calibrated, without the need for specialized calibration data, and therefore may enable fat and iron quantification using data from clinical and research sites that do not have specialized pulse sequences.
Method for Fat Characterization Using MRI Images Acquired Using a Multiple Gradient-Echo Sequence with Bipolar Gradients
It is proposed a method for post-processing images of an region of interest in a subject, the images being acquired with a magnetic resonance imaging technique, the method for post-processing comprising at least the step of:unwrapping the phase of each image,extracting a complex signal over echo time for at least one pixel of the unwrapped images, andcalculating fat characterization parameters by using a fitting technique applied on a model, the model being a function which associates to a plurality of parameters each extracted complex signal, the plurality of parameters comprising at least two fat characterization parameters, the magnitude error and the phase error generated by the use of the bipolar readout gradients, the fitting technique being a non-linear least-square fitting technique using pseudo-random initial conditions.
MAGNETIC RESONANCE IMAGING
A magnetic resonance imaging (MRI) method is provided. The method includes: a first echo signal and a second echo signal generated from each of channels of a MRI device are acquired by performing a pre-scanning according to an imaging sequence; a correction displacement with which an imaging phase consistency is maximum is determined by shifting a signal curve of the second echo signal for each of the channels for a plurality of times; a one-order phase correction value and a zero-order phase correction value for the channels are determined under the imaging sequence according to the correction displacement; a formal scanning is performed according to the imaging sequence to obtain scanning data; and a phase correction is performed on the scanning data according to the one-order phase correction value and the zero-order phase correction value to obtain target scanning data for reconstructing an image.
Method for Reducing Artifacts in Image Data Reconstructed from Measurement Data of an Object Under Examination Captured Using an Echo-Planar Acquisition Technique (EPI)
Techniques are described for complex preprocessing steps to ensure consistency of sorted sets of reference measurement data, which have conventionally been required when sorting reference measurement data sets for DPG algorithms captured using an EPI technique, to be omitted because items of reference measurement data captured via the described techniques are already consistent in themselves. Therefore, for each polarity of the read-out gradients, a set of fully sampled reference measurement data is available, which is already suitable for carrying out a dual-polarity (DP) algorithm without any further measures.
Echo Planar Slice Multiplexing
Method for separating measurement data of an examination object, which data was acquired in collapsed form simultaneously for slices using an EPI SMS technique, into measurement data of individual slices, first and second sets of reference measurement data for separating the measurement data are acquired for each of the slices using a GRE acquisition technique, wherein the reference measurement data in the first set is acquired during switching of readout gradients of a first polarity, and the reference measurement data in the second set is acquired during switching of readout gradients of a second polarity. Based on the two sets of reference measurement data, corresponding separate first calibration data is determined from the reference measurement data acquired using a GRE acquisition technique while switching readout gradients of a first polarity, and second calibration data is determined from the reference measurement data acquired while switching readout gradients of a second polarity.
Identification of advisory regions in breast magnetic resonance imaging
Disclosed herein is a method of medical imaging. The method comprises: receiving (200) an echo planar diffusion weighted magnetic resonance image (122) of a region of interest (309) descriptive of breast tissue; receiving (202) a fat suppressed T2 weighted magnetic resonance image (124) descriptive of the region of interest; segmenting (204) the echo planar diffusion weighted magnetic resonance image to identify high diffusion rate regions (128); segmenting (206) the fat suppressed T2 weighted magnetic resonance image to identify tissue regions (130); identifying (208) a portion of the tissue regions as advisory regions (134) by inputting the high diffusion rate regions and the tissue regions into an image processing module; and providing (210) the advisory regions as a segmentation of the fat suppressed T2 weighted magnetic resonance image.
MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD FOR OBTAINING MAGNETIC RESONANCE IMAGE
A magnetic resonance imaging (MRI) apparatus for obtaining a magnetic resonance (MR) image using a multi-echo pulse sequence including a plurality of repetition times, including a memory configured to store an MR signal obtained using the multi-echo pulse sequence, and an image processor configured to determine a plurality of echo times included in the plurality of repetition times to provide the multi-echo pulse sequence including the plurality of echo times during the plurality of repetition times, and to obtain the MR image, based on the MR signal, wherein the plurality of repetition times includes a first repetition time adjacent to a second repetition time, wherein the plurality of echo times includes a first echo time of the first repetition time, a second echo time of the first repetition time, a first echo time of the second repetition time, and a second echo time of the second repetition time.
Method and magnetic resonance apparatus for image reconstruction with multiple virtual coils
An MR image is produced from data acquired by radiating an RF pulse and switching multiple bipolar magnetic field gradients to generate multiple gradient echoes that are acquired in a raw data set with multiple raw data lines by a reception coil, the multiple gradient echoes being acquired with bipolar magnetic field gradients of different polarity. Due to the bipolar magnetic field gradients of different polarity, in the raw data set first raw data lines are filled with MR signals in one direction in raw data space, and second raw data lines are filled with MR signals in the opposite direction. The MR image is reconstructed from MR signals that have simultaneously been acquired with at least two different reception coils, by generating a first coil raw data set from the raw data set in the image reconstruction, which coil raw data set has only the raw data lines of the raw data set that were filled with MR signals in one direction, and by selecting a second coil raw data set that has only the raw data lines of the raw data set that were filled with MR signals in the other set direction. The MR image is reconstructed from the two coil raw data sets using a parallel imaging reconstruction algorithm, under the assumption that the two coil raw data sets have been acquired by different reception coils.
PARALLEL MULTI-SLICE MR IMAGING WITH SUPPRESSION OF SIDE BAND ARTEFACTS
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 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 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 RF coils (11, 12, 13), and wherein side-band artefacts, namely MR signal contributions from regions excited by one or more side-bands of the multi-slice RF pulses, are suppressed in the reconstructed MR images on the basis of the spatial sensitivity profiles of the 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.
Magnetic resonance imaging method and device
Magnetic resonance imaging method and device, preferably using T2-weighted Fast Spin Echo (FSE) sequences, wherein a first set of magnetic resonance signals corresponding to predetermined phase-encoding gradients and at least one second set of received magnetic resonance signals, corresponding to further predetermined phase-encoding gradients, are acquired from the body under examination, using multi-echo sequences, such that echoes with the same echo index are assigned to different phase-encoding gradients, said first set and said at least one second set being entered into at least two corresponding k-space matrices, and the at least two k-space matrices being combined into a single k-space matrix from which an image is generated, wherein each k-space matrix is incompletely filled such that, for the same phase encoding gradients, one matrix contains the higher-intensity received signals, and at least another matrix contains no signal.