Abstract: 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*2 and R*2, respectively) is alternatively performed.

Abstract: 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.

Abstract: 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.

Abstract: A method for generating a calibrated parallel magnetic resonance image is provided in a manifestation of the invention. A magnetic resonance imaging excitation is applied. A plurality of echoes at different echo times (TE) is acquired. The acquired plurality of echoes from different echo times is used to create a chemical shift corrected calibration map.

Abstract: 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 (T2* and R2*, respectively) is alternatively performed.

Abstract: A method for generating a magnetic resonance images is provided. A first species signal for a first species is generated from magnetic resonance data. A second signal is generated from the magnetic resonance data. The first species signal is combined with the second signal to provide a recombined image. The recombined image may be displayed.

Abstract: A method of separating signals from at least two species in a body using echo-coherent time magnetic resonance imaging is provided. A plurality of echo signals is acquired at acquisition times optimized based on the noise properties of images with different variance with possibly correlated noise resulting in possibly asymmetrically positioned images with respect to an echo time. The plurality of echo signals is combined iteratively by using a maximum likelihood decomposition algorithm for non-identically distributed noise.

Abstract: A method for generating a magnetic resonance images is provided. A magnetic resonance imaging excitation is applied. A plurality of magnetic resonance image signals is acquired. The plurality of image signals is combined iteratively by using a regularized decomposition algorithm. An image created from combining the plurality of image signals iteratively is displayed.

Abstract: A method for generating a self-calibrating parallel multiecho magnetic resonance image is provided. A magnetic resonance imaging excitation is applied. A first echo at a first echo time in a first pattern is acquired. A second echo at a second echo time different from the first echo phase in a second pattern different from the first pattern is acquired. The acquired first echo and acquired second echo are used to generate an image in an image pattern, wherein none of the acquired echoes for generating the image have the same pattern as the image pattern.

Abstract: A method for generating dynamic magnetic resonance images is provided. A cyclical magnetic resonance imaging excitation is applied for a plurality of cycles at a cycle rate. A plurality of magnetic resonance image echoes is acquired for each cycle. A plurality of frames of images is generated from the acquired plurality of magnetic resonance echoes at a frame rate that is at least twice the cycle rate, wherein each frame of the plurality of frames is generated from a plurality of echoes and wherein some of the plurality of frames are generated from magnetic resonance image echoes of adjacent cycles.

Abstract: The acquisition of multiple images at slightly different time shifts from the spin echo (or from TE=0 for gradient echo sequences), allows the separation of on-resonance spins from off-resonance spins by encoding this information in the received signal. The excitation pulse can be a standard broadband excitation that will excite all spins. The separation of on- and off-resonance spins is then performed on the received signal. The polar and equatorial lobes of a magnetic particle such as SPIO produce signals from excited water molecules near the particle which are frequency offset above and below the frequency of signals from water molecules unaffected by the particle.

Abstract: A method for generating a magnetic resonance image is provided. A magnetic resonance imaging excitation is applied for a plurality of cycles at a cycle rate. A plurality of magnetic resonance image echoes is acquired for each cycle. A decay map is estimated from the plurality of magnetic resonance image echoes for each cycle. The estimated decay map is used to generate an image for at least two different species.

Abstract: 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.

Abstract: A water and fat image are acquired using a pulse sequence in which NMR signals for one image data set are acquired with a readout gradient of one polarity and NMR signals for the other image data set are acquired with a readout gradient of the opposite polarity. A misalignment of fat signals caused by chemical shift is corrected by calculating separate water and fat image data sets in k-space and then transforming them to real space images.

Abstract: A multi-point chemical species (e.g., water, fat) separation process which is compatible with rapid gradient echo imaging such as SSFP uses an iterative least squares method that decomposes water and fat images from source images acquired at short echo time increments. The single coil algorithm extends to multi-coil reconstruction with minimal additional complexity.

Abstract: A water and fat image are acquired using a pulse sequence in which NMR signals for one image data set are acquired with a readout gradient of one polarity and NMR signals for the other image data set are acquired with a readout gradient of the opposite polarity. A misalignment of fat signals caused by chemical shift is corrected by calculating separate water and fat image data sets in k-space and then transforming them to real space images.

Abstract: Homodyne image reconstruction is combined with an iterative decomposition of water and fat from MR signals obtained from a partial k-space signal acquisition in order to maximize the resolution of calculated water and fat images. The method includes asymmetrical acquisition of under-sampled MRI data, obtaining low resolution images, and then estimating a magnetic field map and phase maps of water and fat image signals from the low resolution images. The acquired data is again filtered and Fourier transformed to obtain an estimate of combined fat and water signals using the estimated magnetic field map and phase maps. Water and fat images are then estimated from which phases of the water and fat images are determined. The real parts of the water and fat images are then used in calculating water and fat images using a homodyne process.

Abstract: A method of separating signals from water and lipid in a body using spin-echo magnetic resonance imaging comprising steps of acquiring image signals at three acquisition times asymmetrically positioned with respect to a spin-echo time, the three acquisition times being separated by 2?/3 and the middle signal acquisition is centered at ?/2+?k where k is an integer, and combining the plurality of image signals iterative using a least squares decomposition method.

Abstract: A generalized multi-point fat-water separation process is combined with steady-state free precession (SSFP) to obtain high quality images of articular cartilage with reduced imaging time.

Abstract: The invention provides a method of magnetic resonance imaging. A magnetic resonance imaging apparatus having a plurality of gradient axes is employed. A plurality of imaging planes are employed with respect to the gradient axes. A plurality of gradient referencing pre-scans are executed for the imaging planes to provide a plurality of calibration correction values for the imaging planes. A specimen is employed with respect to the gradient axes. An imaging plane is selected with respect to the specimen, and a main magnetic field is established with respect to the specimen. Radio frequency pulses are applied to the specimen to produce magnetic resonance signals. The calibration correction values for the selected imaging plane are employed to adjust a plurality of gradient waveforms. The gradient waveforms are output as a plurality of magnetic field gradients with respect to the gradient axes.