G01R33/56316

PHASE OFFSET ERROR CORRECTION FOR DISPLACEMENT-ENCODED MR IMAGES
20200088820 · 2020-03-19 ·

A system includes acquisition of a plurality of displacement-encoded magnetic resonance (MR) phase images, determination of first pixels associated with one or more image regions of the plurality of displacement-encoded MR phase images, determination of representative pixel values of the first pixels based on pixel values of the first pixels within one or more of the plurality of displacement-encoded MR phase images, determination of a relationship between background phase offset error and pixel location based on the determined representative pixel values and the pixel locations of the first pixels, determination of a background phase offset error for each of one or more other pixels of the plurality of displacement-encoded MR phase images based on the relationship and on the pixel locations of the one or more other pixels, and generation of a corrected MR phase image of one of the plurality of displacement-encoded MR phase images based on the background phase offset error determined for each of the one or more other pixels.

Image processing apparatus and magnetic resonance imaging apparatus

An image processing apparatus according to an embodiment includes conversion circuitry, magnitude image generating circuitry and phase image generating circuitry. The conversion circuitry is configured to convert time-series k-space data into first time-series x-space data, the x-space representing a spatial position. The magnitude image generating circuitry is configured to generate a magnitude image from second time-series x-space data, the second time-series x-space data being acquired by applying a first filter to the first time-series x-space data. The phase image generating circuitry is configured to generate a phase image from third time-series x-space data, the third time-series x-space data being acquired by applying, to the first time-series x-space data, a second filter that is different from the first filter.

4D flow measurements of the hepatic vasculatures with two-dimensional excitation
10588523 · 2020-03-17 · ·

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.

Comprehensive Cardiovascular Analysis with Volumetric Phase-Contrast MRI
20200049784 · 2020-02-13 ·

Processing techniques of volumetric anatomic and vector field data from volumetric phase-contrast MRI on a magnetic resonance imaging (MRI) system are provided to evaluate the physiology of the heart and vessels. This method includes the steps of: (1) correcting for phase-error in the source data, (2) visualizing the vector field superimposed on the anatomic data, (3) using this visualization to select and view planes in the volume, and (4) using these planes to delineate the boundaries of the heart and vessels so that measurements of the heart and vessels can be accurately obtained.

MRI APPARATUS
20200037918 · 2020-02-06 · ·

In one embodiment, an MRI apparatus includes a memory storing a predetermined program and processing circuitry. The processing circuitry is configured, by executing the predetermined program, to generate a first image having a first phase affected by susceptibility, generate a second image having a second phase affected by both of the susceptibility and flow, and distinguish difference in susceptibility or flow for a pixel of a third image by using the first phase and the second phase or by using a value calculated from the first phase and a value calculated from the first phase, the third image having regions which are substantially same in contrast.

Method for determining a personalized cardiac model using a magnetic resonance imaging sequence

A method is provided for determining a personalized cardiac model, including steps of (i) computing a velocity time profile of a blood flow across a selected area of the heart or the aorta during at least one cardiac cycle, using data acquired with a Magnetic Resonance Imaging (MRI) device; (ii) performing a segmentation of the velocity time profile so as to identify cardiac phases according to a predefined generic cardiac model; and (iii) computing normalized time location and/or duration of the cardiac phases within cardiac cycles so as to define a personalized cardiac model.

LINEAR PHASE-CORRECTED LOCAL AVERAGING OF MR IMAGE DATA

In a method for filtering magnetic resonance (MR) image data, complex MR image data is acquired from a region to be imaged, and a sliding window averaging is applied to the complex MR image data to generate filtered MR image data. For each window position of the sliding window averaging: a phase variation of the complex MR image data of individual image points of a sliding window is estimated with a model using a linear phase progression, and filtered complex MR image data is generated based on the estimated phase variation of the complex MR image data. The generation of the filtered complex MR image data uses an average formation of the complex MR image data of the individual image points of the sliding window.

Bayesian model for highly accelerated phase-contrast MRI

Methods and systems for accelerated Phase-contrast magnetic resonance imaging (PC-MRI). The technique is based on Bayesian inference and provides for fast computation via an approximate message passing algorithm. The Bayesian formulation allows modeling and exploitation of the statistical relationships across space, time, and encodings in order to achieve reproducible estimation of flow from highly undersampled data.

System for processing images to detect properties of skeletal muscle

Machine readable instructions, a data processing apparatus and a method are provided to determine one or more properties of motor units of skeletal muscle by analyzing a time series of Magnetic Resonance, MR, images representing a slice of a body part to identify signal voids in one or more images of the series. A comparison of at least one characteristic of the identified signal voids in the images is performed with a control data set of MR images produced by applying a controlled stimulus to a motor nerve to establish inherent characteristics of signal voids corresponding to motor units of skeletal muscle. Properties of candidate motor units are analyzed to confirm or reject them as motor units and at least one of: a firing frequency of at least one of the confirmed motor units, a size of at least one of the confirmed motor units, a number of confirmed motor units in a given image area or a shape of at least one of the confirmed motor units is determined.

MR imaging using Dixon-type water/fat separation with suppression of flow-induced leakage and/or swapping artifacts

The invention relates to a method of Dixon-type MR imaging. It is an object of the invention to provide a method that enables efficient and reliable Dixon water/fat separation, in particular using a bipolar acquisition strategy, while avoiding flow-induced leakage and swapping artifacts. According to the invention, an imaging sequence is executed which comprises at least one excitation RF pulse and switched magnetic field gradients, wherein pairs of echo signals are generated at two different echo times (TE1, TE2) and during two or more different cardiac phases (AW1, AW2). The echo signals are acquired and phase images are reconstructed therefrom. A final diagnostic image is reconstructed from the echo signal data using water/fat separation, wherein regions of flow and/or or estimates of flow-induced phase errors are derived from the phase images to suppress or compensate for flow-induced leakage and/or swapping artifacts in the final diagnostic image. Therein, flow-induced phase offsets are determined by voxel-wise comparison of the phase images associated with the different cardiac phases. Moreover, the invention relates to a MR device (1) and to a computer program to be run on a MR device (1).