Patent application number | Description | Published |
20080275329 | Diffusion weighted preparatory sequence for magnetic resonance imaging pulse sequence - A preparatory pulse sequence is applied prior to an imaging pulse sequence during a diffusion-weighted MRI scan. The preparatory pulse sequence diffusion weights the longitudinal magnetization using a gradient waveform that is first moment nulled to reduce image artifacts caused by patient motion. | 11-06-2008 |
20090261823 | METHOD FOR WATER-FAT SEPARATION AND T2* ESTIMATION IN AN MRI SYSTEM EMPLOYING MULTIPLE FAT SPECTRAL PEAKS AND FAT SPECTRUM SELF-CALIBRATION - NMR signal contributions from water and fat are separated using a model of the fat resonant frequency spectrum that has multiple resonant peaks. The relative frequencies of the multiple fat spectrum peaks are known a priori and their relative amplitudes are determined using a self-calibration process. With the determined relative amplitudes of the fat spectrum peaks, acquired NMR signals are modeled. Using this model and NMR signal data acquired at a plurality of echo times (TE), the signal contribution from multiple fat spectrum peaks is separated from the acquired NMR signal data. A combined image is alternatively produced from weighted contributions of the separated water and fat images. Additionally, a more accurate estimation of the apparent relaxation time and rate (T | 10-22-2009 |
20100185081 | MAGNETIC RESONANCE THERMOMETRY IN THE PRESENCE OF WATER AND FAT - The in vivo measurement of tissue temperature is performed during a medical procedure using an MRI system. Fat and Water images are acquired at each temperature measurement time and corresponding phase images are produced. A temperature map is produced by subtracting the phase at each Fat image pixel from the corresponding pixel in the Water phase image to improve measurement accuracy in tissues with fat/water mixtures. | 07-22-2010 |
20110254547 | METHOD FOR SEPARATING MAGNETIC RESONANCE IMAGING SIGNALS USING SPECTRAL DISTINCTION OF SPECIES - A method for producing an image of a subject with a magnetic resonance imaging (MRI) system in which a signal contribution of a chemical species is depicted and a signal contribution of another chemical species is substantially separated is provided. For example, the provided method is applicable for water-fat separation. Spectral differences between at least two different chemical species are exploited to produce a weighting map that depicts the likelihood that one chemical species being depicted as another. A weighting map that characterizes the smoothness of a field map variation is also produced. These weighting maps are utilized to produce a correct field map estimate, such that a robust separation of the signal contributions of the at least two chemical species can be performed. | 10-20-2011 |
20130214781 | System and Method for Magnetic Resonance Imaging Water-Fat Separation with Full Dynamic Range Using In-Phase Images - A magnetic resonance imaging (“MRI”) system and method for producing an image of a subject with the MRI system in which signal contributions of water and fat are separated are provided. A plurality of in-phase echoes formed at a plurality of different echo times are sampled to acquire k-space data. The in-phase echoes include signal contributions from water and fat that are in-phase with each other. The signal contributions from water and fat are then separated by fitting only those echo signals that are in-phase echo signals to a signal model that models a fat spectrum as including multiple resonance peaks. From these signal contributions, an image of the subject depicting a desired amount of signal contribution from water and a desired amount of signal contribution is produced. | 08-22-2013 |
20140043023 | SYSTEM AND METHOD FOR ACCELERATED MAGNETIC RESONANCE IMAGING USING SPECTRAL SENSITIVITY - A system and method for accelerated magnetic resonance imaging (MRI) using spectral sensitivity information are provided. The MRI system is used to acquire k-space data from a subject that when positioned in the main magnetic field of the MRI system causes inhomogeneities in the main magnetic field. Spectral sensitivity information is derived from the acquired k-space data. In general, the spectral sensitivity information relates specific resonance frequencies to distinct spatial locations in the main magnetic field of the MRI system. One or more images of the subject may be reconstructed from the acquired k-space data using the produced spectral sensitivity information to spatially encode the acquired k-space data. By using the spectral sensitivity information to provide spatial-encoding, the data acquisition can be accelerated, for example, by undersampling k-space. In addition, using the provided system and method, clinically viable images can be obtained in the presence of severe off-resonance. | 02-13-2014 |
20140142417 | System and Method for Assessing Susceptibility of Tissue Using Magnetic Resonance Imaging - A system and method for assessing magnetic susceptibility of tissue of a subject using a magnetic resonance imaging (MRI) system to acquire chemical-shift-encoded, water-fat separated data. From the water-fat separated data, separated water and fat images, as well as a magnetic field inhomogeneity map are used to estimate the magnetic susceptibility within tissue. | 05-22-2014 |
20140233817 | System and Method For Magnetic Resonance Imaging Parametric Mapping Using Confidence Maps - A method for producing parametric maps using a magnetic resonance imaging (MRI) system is provided. The MRI system is used to acquire k-space data from a field-of-view. A series of images is reconstructed from the acquired k-space data, and a confidence map is produced using the k-space data. The confidence map depicts regions in the field-of-view that are affected by error sources. A parametric map is produced using the reconstructed series of images and the produced confidence map. Values in the parametric map associated with regions in the field-of-view depicted in the confidence map as being affected by error sources are not computed, thereby reducing errors in the parametric map. | 08-21-2014 |