Abstract:
In a method for a rapid determination of spatially resolved magnetic resonance relaxation parameters in an area of examination, a preparation pulse is radiated into the area of examination. During the relaxation of the longitudinal magnetization, spatially encoded magnetic resonance signals are acquired at a minimum of two different points in time using a fast magnetic resonance sequence. At each inversion time, an image data record is reconstructed from the magnetic resonance signals, which are elastically registered to each other. From the recorded image data records, values of magnetic resonance relaxation parameters are spatially accurately determined.
Abstract:
Magnetic resonance reconstruction includes motion compensation. Inverse-consistent non-rigid registration is used to determine motion between shots. The motion is incorporated into reconstruction. The incorporation compensates for the motion resulting from the period over which the MR data is acquired.
Abstract:
Phase sensitive T1 mapping is provided in magnetic resonance (MR). The phase from samples of a modified Look-Locker inversion recovery sequence may be used to normalize contrast, allowing for accurate motion registration without extra information acquisition. The sign may be estimated, allowing T1 mapping with a single application of a non-linear fit.
Abstract:
A method for correcting the background phase in magnetic resonance phase contrast flow images includes providing a time series of velocity encoded magnetic resonance images of a patient, where the time series of velocity encoded images comprises for each time point a phase contrast image where a pixel intensity is proportional to a flow velocity, measuring a change of intensity for each pixel over the time series of phase contrast images, identifying pixels with a low measure of temporal change as stationary pixels, and calculating a correction field for the stationary pixels, where the correction field represents a background phase to be subtracted from the phase contrast image.
Abstract:
A method for performing motion compensation in a series of magnetic resonance (MR) images includes acquiring a set of MR image frames spanning different points along an MR recovery curve. A motion-free synthetic image is generated for each of the acquired MR image frames using prior knowledge pertaining to an MR recovery curve. Each of the acquired MR images is registered to its corresponding generated synthetic images. Motion within each of the acquired MR image is corrected based on its corresponding generated synthetic image that has been registered thereto.
Abstract:
A method including receiving an image sequence, wherein the image sequence includes a plurality of two-dimensional (2D) image frames of an organ arranged in a time sequence; constructing a three-dimensional (3D) volume by stacking a plurality of the 2D image frames in time order; detecting a best bounding box for a target of interest in the 3D volume, wherein the best bounding box is specified by a plurality of parameters including spatial and temporal information contained in the 3D volume; and determining the target of interest from the best bounding box.
Abstract:
A method for clinical parameter derivation and adaptive flow acquisition within a sequence of magnetic resonance images includes commencing an acquisition of a sequence of images. One or more landmarks are automatically detected from within one or more images of the sequence of images. The detected one or more landmarks are propagated across subsequent images of the sequence of images. A plane is fitted to the propagation of landmarks. The positions of landmarks or alternatively the position of the fitted plane within the sequence of images is used for derivation of clinical parameters such as tissue velocities and/or performing adaptive flow acquisitions to measure blood flow properties.
Abstract:
The present invention relates to an adsorbed gas content measuring instrument and its testing method. The instrument comprises sealed cylinders, gas collecting graduated canisters and a test box, wherein the sealed cylinders are provided with valves, the gas collecting graduated canisters are equipped with drain hole adjustment valves and vent hole switching valves fit for the valve ports, and there is a heating element and a temperature controller in the test box. The method is mainly as follows: put gas-contained samples and saturated brine into the sealed cylinder, seal the cylinder, feed water in the test box and heat the box, place the sealed cylinder into the water bath of the test box, introduce saturated brine into the gas collecting graduated canister, connect the canister and cylinder, open the drain hole of the gas collecting graduated canister, record the liquid level of the graduated canister and cut off the connection after the test. The present invention has a compact structure, small volume, good gas tightness, accurate measurement, uniform heating and simple testing operation, is easy to move and carry, and suitable for field application. It can be specially used for collecting and measuring various gases, especially small-volume gas, thus it is more practical in applications.
Abstract:
A high-resolution Subspace-Least Mean Square (S-LMS) method for harmonic and interharmonic measurement in power systems is provided. The eigenvector corresponding to the smallest eigenvalue is used to calculate the frequencies of the signal, and the least mean square method is used to estimate the amplitude and phase angle of harmonic and interharmonic components based on the computed frequencies and time domain measurements of the signal. Three schemes, namely sparsity, catch-and-pinpoint, and hybrid are presented. The S-LMS method provides accurate phasor, harmonic and interharmonic measurements for power system monitoring. The speed, accuracy, and resilience of the S-LMS method can be further increased by each of the three schemes. The method has a wide range of applications in power quality analyzers, synchronized phasor measurement, situational awareness, dynamic equivalencing, and smart meters.
Abstract:
Parallel imaging magnetic resonance reconstruction is performed with temporal sensitivity. Rather than estimate the coil sensitivity once for each coil of an array, the coil sensitivity at different times is estimated. The movement of the patient may result in different sensitivities at different times. By using the time varying sensitivity in iterative, self-consistent, non-linear parallel imaging, real-time imaging may be provided with stable artifacts in view of increasing SNR even with higher reduction factors (e.g., 4-6).