Siemens Aktiengesellschaft

Siemens Healthcare Gmbh

Siemens Schweiz Ag

Centre Hospitalier Universitaire Vaudois

UniversitÉ De Lausanne

Universitaetsspital Basel

Gunnar Krueger

Tobias Kober

Thorsten Feiweier

Tom Hilbert

Arne Littmann

Oliver Bieri

Davide Piccini

Cristina Granziera

Guillaume Bonnier

Damien Nguyen

Delphine Ribes

Stefan Kannengiesser

A method for adapting a medical system to an object movement during medical examination of the object and a medical system configured for carrying out the method. The medical system has a device for detecting and quantifying a motion of the object before or during an acquisition of diagnostic data. The system for detecting and quantifying a motion of the object is able to directly identify and qualify the occurrence of object motion and to automatically suggest an adaptation of the diagnostic data acquisition strategy/technique as a function of the object motion.

Method for adapting a medical system to patient motion during medical examination, and system therefor

A method improves a detection of a brain tissue pathology in magnetic resonance (MR) images of a patient. The method includes acquiring multiple MR imaging data for creating four different contrast maps of a patient brain. From the multiple MR imaging data, performing an estimation of gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) concentration for each voxel of a part of the patient brain. From the multiple MR imaging data, segmenting the part of the patient brain in different regions-of-interest (ROIs) according to a chosen atlas. For each voxel of each of the contrast maps of the patient brain, computing, for the part of the patient brain, a deviation score. The method further includes creating from the deviation score and for each of the quantitative contrast maps, a deviation map representing the part of the brain in dependence on the deviation score calculated for each voxel.

Apparatus and method for visualizing tissue macro- and microstructure for pathology evaluation in magnetic resonance imaging

A method for improving image homogeneity of image data acquired from balanced Steady-State Free Precision (bSSFP) sequences in magnetic resonance imaging. Multiple bSSFP sequences are performed with different radio frequency phase increments to create multiple bSSFP image volumes with different phase offsets &#x3d5;. Each image has voxels whose intensity M is a function of a nuclear resonance signal (or magnetization) measured by the MR imaging apparatus. Per-voxel fitting of a mathematical signal model onto the measured magnetization of the field of view in function of the phase offsets &#x3a6;. Then the spin density M, the relaxation time ratio &#x39b; and the local phase offset &#x394;&#x3a6; are determined from the fit for each voxel. A homogeneous image of the object is generated by calculating the signal intensity in each voxel, using the spin density Mand the relaxation time ratio &#x39b;, wherein &#x394;&#x3a6; is chosen such that &#x3a6;&#x2212;&#x394;&#x3a6;=0&#xb0;.

Apparatus and method for improving balanced steady-state free precision in magnetic resonance imaging

An atlas-free magnetic resonance imaging method images at least one part of a brain. An MRI sequence configured for acquiring two image volumes of the part at different inversion times within a single acquisition is combined to a fat-water separation method for acquiring a fat-water separated image. For each echo time two image volumes are acquired, respectively a first image volume and a second image volume at the first echo time, and a first image volume and a second image volume at the second echo time, and combined to a uniform image. The acquired images are combined to form a final uniform image, a final fat-water separated image, and a final second image volume that are fed into a multichannel image segmentation algorithm using a Markov random field model for segmenting the part into multiple classes of cranial tissues, in order to obtain a segmented image of said part.

Atlas-free brain tissue segmentation method using a single T1-weighted MRI acquisition

A motion detection system detects object motion in a medical imaging system. The computer-implemented calibration method includes an automatic calibration process for determining a motion threshold for the object motion detection system, while the object is positioned for imaging by the medical imaging system. The calibration process includes: repeatedly acquiring motion detection data and repeatedly acquiring motion quantification data with a motion quantification system. The motion quantification data are analyzed to determine whether the object was mobile or immobile. If the object was immobile, an object motion threshold for the motion detection system is determined by statistical analysis of the motion detection data. If the object was mobile, the detection and quantification data are correlated for determining an object motion threshold for the motion detection system, the threshold being determined from motion detection data correlated to motion quantification data characterizing an object motion within a predefined tolerance value.

Method for automatic calibration of motion detection techniques in medical imaging systems

A method detects phase-encoding ghosting in a MR image of an object to be imaged and mitigates the corresponding artifact in the MR image. The method includes acquiring MRI raw data of the object by a MRI apparatus. The MRI apparatus has multiple receiver channels for acquiring the MRI raw data. An artifact map of at least one part of the object to be imaged is calculated from the MRI raw data, the artifact map is configured for highlighting artifact appearing in the MR image. An outlier mask representing detected phase-encoding artifact is created in the artifact map. The phase-encode ghosting in the MR image is mitigated by using the previously obtained artifact map and the outlier mask for obtaining an improved MR image.

Method, computer readable medium and MRI apparatus for performing phase-encode ghosting detection and mitigation in MRI

A method and a magnetic resonance imaging apparatus provide subject/object motion detection and correction during a MRI scan. The method includes generating via a magnetic resonance scanner a magnetic field gradient and a radio-frequency signal for the MRI scan. The radio-frequency signal contains a successive repetition of pulse sequences, each pulse sequence starting with a radio-frequency excitation pulse. A time between two successive radio-frequency excitation pulses are defined as a repetition time. Detecting, from a readout signal emitted in response to the pulse sequence, time-points in which motion has occurred. Interleaves are automatically created. A sampling of the k-space is performed by arranging k-space MRI readout signals acquired over each repetition time of the pulse sequence into several groups of interleaves of uniform k-space sampling reconstructing separately each subset of interleaves for obtaining low resolution MR images.

Method and apparatus for performing guided and flexible self-navigated structural MRI for motion compensation

In a method and magnetic resonance (MR) apparatus for determination of movement of an examination subject during the acquisition of (MR) measurement data using at least two antenna elements that exhibit respectively different spatial positions, after each radiated excitation pulse a navigator signal is acquired in the measurement data and movement of the examination subject between two excitation pulses during the acquisition of the measurement data is determined from a change of the signal strength of the navigator signal in the at least two antenna elements and based on the respective spatial positions of the antenna elements.

Method and magnetic resonance apparatus for determination of patient movement during data acquisition

A method removes a part representing non-brain tissue of the MR brain image. For each generated magnetic field gradient, acquiring a current signal respectively at a first time of echo TEafter an excitation radio frequency pulse and at a second time of echo TEafter the radio frequency pulse. The MR brain image of an internal structure of the target. The first time of echo TEand the second time of echo TEare adjusted for correlating time of echo difference &#x394;TE=TE&#x2212;TEwith a fat and water mutual resonance frequency difference &#x3b4;, and in that fat and water information encoded in the current signal resulting from the correlation of the second and first time of echo difference &#x394;TE with the fat and water mutual resonance frequency difference is used as an additional input source into a multispectral analysis method for removing the part.

Magnetic resonance imaging

A method for determining motion parameters of an object by way of at least one coil within a magnetic field adapted for a magnetic resonance based imaging device. Induced pulses are emitted on the coil in order to provide navigator signals that are finally measured in order to provide a spatial position of the object relative to the coil. At least one reference displacement of the object relative to the coil that is spatially and metrically predefined between two positions of the object is generated so that intensity changes of navigator signals at the coil are measured and recorded in a calibration map. Then, for determining each one of a sequence of further positions of an object in motion relatively to the coil, a navigator signal of the coil is measured and is compared to values of intensity changes from the calibration map in order to provide a corrected value of displacement of the object that is recovered from the calibration map and processed so that absolute values of motion parameters of the object are determined.

Method for determining motion parameters of an object in a magnetic field

In a method and apparatus for magnetic resonance imaging on the basis of a gradient echo sequence by excitation of nuclear spins and measurement of radio-frequency signals arising from the excited nuclear spins:

Method and apparatus for magnetic resonance imaging on the basis of a gradient echo sequence

In a method and apparatus for accelerated spiral-coded imaging in magnetic resonance tomography using spiral-shaped k-space sampling, the underlying k-matrix is under-sampled such that an additional spiral is obtained by point mirroring of the measured values at the center of the k-matrix. This additional spiral forms a complete data set of the k-matrix together with the first spiral for imaging the output information.

Growing community of inventors

Watertown-Boston, MA, United States of America

Gunnar Krueger