Patent classifications
G01R33/56316
PERFORATOR PHASE CONTRAST ANGIOGRAPHY (pPCA)
The present disclosure is directed to methods and systems for fusing Phase Contrast Angiography (PCA) with anatomic images to create a perforator PCA (pPCA) data set. In the pPCA) method, vascular and anatomic information may be provided by different MRI sequences. A four-point acquisition scheme may be used for 3D PCA acquisition of vascular images. Anatomical MRI images are acquired and may be enhanced with image post-processing techniques. The vascular and anatomical images may be combined with image fusion to create a high resolution map of abdominal wall vasculature. This high resolution map visualizes not only the size and location of the DIEP perforators, but also their relationship with surrounding tissue, and the blood flow velocity within them. As such, the fused pPCA image has substantially higher SNR and CNR than CTA image of the same slice thickness.
Time-resolved phase-contrast MR imaging with speed encoding
In a method and apparatus for time-resolved phase-contrast magnetic resonance (MR) imaging with speed encoding, MR signals are detected with multiple receivers in each of numerous time segments in order to acquire raw data in each of the time segments, in each case for numerous MR images with different speed encodings. Stationary image points and/or non-stationary image points are identified, dependent on the detected MR signals. A mask is defined, dependent on the identified stationary image points and/or the non-stationary image points, wherein the mask is locally variable. The numerous MR images for the numerous time segments are reconstructed from the acquired raw data, wherein the reconstruction occurs in an iterative process and with a temporal regularization, which is dependent on the mask.
DIXON MR IMAGING WITH SUPPRESSION OF FLOW ARTIFACTS
The invention relates to a method of MR imaging of a body (10) of a patient. It is an object of the invention to provide a method that enables efficient compensation of flow artifacts, especially for MR angiography in combination with Dixon water/fat separation. The method of the invention comprises the steps of: a) generating MR echo signals at two or more echo times by subjecting the portion of the body (10) to a MR imaging sequence of RF pulses and switched magnetic field gradients, wherein the MR imaging sequence is a Dixon sequence; b) acquiring the MR echo signals; c) reconstructing one or more single-echo MR images from the MR echo signals; d) segmenting the blood vessels from the MR images; e) detecting and compensating for blood flow-induced variations of the amplitude or phase in the single-echo MR images within the blood vessel lumen, and f) separating signal contributions from water and fat spins to the compensated single-echo MR images. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).
SYSTEM AND METHOD FOR IMAGING FOUR-DIMENSIONAL FLOW OF A FLUID WITHIN A VOLUME OF AN IMAGED OBJECT
A method for phase-contrast imaging a fluid within a volume of an imaged subject is provided. The method includes acquiring a plurality of slabs, each slab imaging the fluid flowing within a portion of the volume; and volume merging the plurality of slabs to form an image of the volume. Each slab of the plurality is aligned with respect to the volume such that each slab of the plurality is continuously supplied with a plurality of magnetically unsaturated portions of the fluid during acquisition.
SYSTEMS AND METHODS FOR FREE-BREATHING CINE DENSE MRI USING SELF-NAVIGATION
Some aspects of the present disclosure relate to systems and methods for free-breathing cine DENSE MRI using self-navigation. In one embodiment, a method includes acquiring magnetic resonance data for an area of interest of a subject, wherein the acquiring comprises performing sampling with phase-cycled, cine displacement encoding with stimulated echoes (DENSE) during free-breathing of the subject; identifying, from the acquired magnetic resonance data, a plurality of phase-cycling data pairs corresponding to matched respiratory phases of the free-breathing of the subject; reconstructing, from the plurality of phase-cycling data pairs, a plurality of intermediate self-navigation images; performing motion correction by estimating, from the plurality of intermediate self-navigation images, the respiratory position associated with the plurality of phase-cycling data pairs; and reconstructing a plurality of motion-corrected cine DENSE images of the area of interest of the subject.
METHODS FOR CO-IMAGING TISSUE STIFFNESS AND BLOOD FLOW IN AN MRI SCAN
Techniques for co-imaging tissue stiffness and blood flow using a single MRI scan are disclosed. The methods use a combined gradient waveform that provides adequate sensitivity for concurrent encodings of flow and tissue stiffness. During a scan, the application of the combined gradient waveform, in the presence of an applied oscillatory motion, simultaneously encodes both flow and stiffness information into the phase of the resulting MRI image. To separate the flow information from the tissue displacement caused by the oscillatory motion, a Fourier transform applied along the direction of applied oscillatory motion. After the transformation, baseband information (flow velocity) may be separated from modulated information (tissue displacement). The separated data may be used to create a velocity map and a displacement map, which can then be converted to a stiffness map.
4D Flow Measurements Of The Hepatic Vasculatures With Two-Dimensional Excitation
A computer-implemented method of visualizing blood flow through a patient using magnetic resonance imaging (MRI) includes receiving an image of the portal venous system of the patient's liver at a full field of view. A reduced field of view is defined which encompasses the portal venous system of the patient's liver and excludes extraneous anatomy in the full field of view. A navigator area is defined in the full field of view and outside of the reduced field of view. Transmit channels are used to selectively excite the reduced field of view and the navigator area throughout a cardiac cycle of the patient. Measurement data is acquired in response to the selective excitation. The acquired data is used to generate time-resolved 3D datasets. Additionally, a 3D visualization of blood flow though the portal venous system is generated based on the time-resolved 3D datasets.
Magnetic resonance imaging apparatus and a method for determining trigger timing of CE-MRA scan
The present invention discloses an apparatus and a method for determining a trigger timing of a CE-MRA scan. The apparatus comprises: a blood flow velocity acquisition unit configured to acquire a blood flow velocity of a target vessel; and a trigger timing determination unit configured to determine the trigger timing for performing the CE-MAR scan on a CE-MRA scan region according to the blood flow velocity and a predetermined image acquisition condition during a monitoring scan. The apparatus and method take the blood flow velocity into consideration, and can determine the trigger timing of the CE-MRA scan automatically and accurately.
Method for performing an angiographic measurement
A method is for performing an angiographic measurement of a main measurement region of a patient via a magnetic resonance system. An embodiment of the method includes performing at least one overview measurement to generate overview-measurement data; defining, using the overview-measurement data, the main measurement region and a first measurement region, the first measurement region differing from the main measurement region; performing a first time-resolved measurement in the first measurement region defined to generate first time-resolved measurement data; detecting an injected contrast agent bolus in the first measurement region using the first time-resolved measurement data; determining a flow rate of the injected contrast agent bolus detected; setting at least one measurement parameter of the angiographic measurement according to the flow rate determined; and performing the angiographic measurement of the main measurement region of the patient in the magnetic resonance system using the at least one measurement parameter set.
Compressed sensing MR image reconstruction using constraint from prior acquisition
The invention relates to a method of MR imaging of at least a portion of a body (10) of a patient placed in an examination volume of a MR device (1), the method comprising the steps of: —subjecting the portion of the body (10) to a first imaging sequence for acquiring a first signal data set (21); —subjecting the portion of the body (10) to a second imaging sequence for acquiring a second signal data set (23), wherein the imaging parameters of the second imaging sequence differ from the imaging parameters of the first imaging sequence; —reconstructing a MR image from the second signal data set (23) by means of regularization using the first signal data set (21) as prior information. Moreover, the invention relates to a MR device (1) and to a computer program for a MR device (1).