General Electric Company

General Electric Cgr S.a.

Ge Medical Systems Global Technology Company, LLC

Patrick L Le Roux

Richard Scott Hinks

Thomas K Foo

Ralph Eugene Hurd

James S Tropp

Napapon Sailasuta

Yi Sun

An NMR image of a patient's heart uses SSFSE (single shot fast spin echo) type pulses to condition the body by a preparation of a phase-encoding gradient pulse whose duration differs from one sequence to another so as to define, from one sequence to another, a different effective echo time. At each sequence an image is displayed representing the discrimination of the contributions of the particles of the body as a function of their time Tcompared with this effective time. For the heart, with a single respiration on the part of the patient, lesions due to infarction and transplant rejection are revealed.

Method and apparatus for MR image acquisition

In the acquisition of NMR signals in FSE or fast spin echo type sequences the emission phase of the 180&#xb0; refocusing pulse evolves quadratically. In order to prevent problems of oscillation of the output signal, the sequence is subjected to a preparation pulses. A history is provided for the common difference of the quadratic sequence of the phase variation with respect to the first seven refocusing pulses. This history leads to an immediate thermal equilibrium.

Method and apparatus for fast imaging by nuclear magnetic resonance

A method of excitation for use during an NMR examination includes the subjecting of a body () to an orienting magnetic field (B). The body () is adiabatically conditioned with a first series of Rf pulses (IP&#x2013;IP). The body () is excited with a second series of RF pulses (E&#x2013;E) in a presence of gradient field pulses. A resonance signal is emitted from the body () in response to the second series of RF pulses (E&#x2013;E).

NMR excitation method

In an MRI system a fast spin echo pulse sequence is employed to acquire data for producing an image. The phase of successive RF refocusing pulses in the sequence is shifted by a sweep factor and an odd echo signal and an even echo signal is acquired for each view. Two k-space data sets are formed, one by summing the even and odd echo signal pairs and the other by subtracting the echo signal pairs. Two magnitude images are reconstructed from the respective k-space data sets and an output image is formed by combining these two images.

Non-CPMG fast spin echo MRI method

Chemical shift error in proton magnetic resonance spectroscopy is reduced by applying a volume excitation pulse sequence such as PRESS and very selective out-of-volume saturation pulses to limit that volume to a volume-of-interest free of the misregistration errors associated with the excitation sequence. The resulting volume is then only limited by the very small chemical shift misregistration of the very selective saturation pulses.

Magnetic resonance spectroscopic imaging having reduced chemical shift

Slabs are selected using a combination of a slab select gradient and selective RF excitation pulses to acquire 3D NMR data. Thinner 2D slices are selected within each slab by employing virtual frequency encoding of the acquired NMR signals. This encoding is achieved by stepping the value of the gradient in the slab select direction and concurrently changing the time interval between RF excitation and acquisition of the resulting NMR echo signal. A gradient recalled echo pulse sequence and a fast spin echo pulse sequence are described.

Virtual frequency encoding of acquired NMR image data

A fast spin echo NMR pulse sequence is modified to stabilize the magnitude of early NMR echo signals produced during each shot. Stabilization is accomplished by modifying the amplitude of the nutation angle produced in the spins by the corresponding RF refocusing pulses. When selective RF refocusing pulses are employed the slice is divided into subslices and the modifications are made separately to each subslice.

Stabilized fast spin echo NMR pulse sequence

An NMR system performs a 2DFT or 3DFT scan using a set of steady-state free precession (SSFP) pulse sequences. A contrast preparation pulse sequence precedes each series of SSFP pulse sequences and it includes a spectrally selective RF inversion pulse timed to water to provide T.sub.1 contrast between tissues having relatively long T.sub.1 times, followed by a spectrally selective RF inversion pulse tuned to suppress the signals from fat.

Fast NMR image acquisition with spectrally selective inversion pulses

In an NMR experiment, the movements of an object are represented by carrying out a harmonic analysis of the images based on a resolution of the movement of the object into a Fourier series. There is then obtained a set of images which is representative of the Fourier components of this movement. The images are then recombined at will so as to produce either a general moving image, or an image of those parts which are motionless in the object, or finally an image of only those parts which are in motion.

Method for recording movements inside an object and for showing on an

NMR machine with low field and dynamic polarization

Method for the measurement of the effects of eddy currents

Method for depiction of moving parts in a body by nuclear magnetic

In a nuclear magnetic resonance experiment, the flows are measured by causing the orientation of the magnetic moments of the particles located in a slice to flip and by subsequently causing the scattering of the phases of the magnetic resonance signals to be reflected only for particles which have migrated into a slice adjacent to the slice in which the flipping has been done. It is shown that the relative dynamic range of the measured NMR signal for the moving parts in relation to the measured signal for the fixed parts becomes infinite.

Method for measuring flows in a nuclear magnetic resonance experiment

So-called motion artifacts are removed in NMR imaging experiments by choosing a 2DFT type imaging method and by choosing a phase encoding pitch, which is a multiple of a useful encoding pitch determined by the height of the image field to be depicted. It is shown that, after the image reconstruction has been computed by Fourier transform, the central image corresponds to the depiction of the continuous components of the magnetic moments of the particles located in an examined cross-section of a body under examination, and that these continuous components are not affected by all the variations in the rate of a cyclical phenomenon which disturbs the images (in general the cardiac cycle).

Growing community of inventors

Palaiseau, France

Patrick L Le Roux