Kabushiki Kaisha Toshiba

Kabushiki Kaishi Toshiba

Masahiko Hatanaka

Yoshio Machida

Hirokazu Suzuki

Shinichi Kitane

Fumitoshi Kojima

A method and an apparatus of nuclear magnetic resonance imaging capable of reducing the processing time in general, providing the nuclear magnetic resonance images with improved contrast among the imaged elements and reduced background noises, providing thee nuclear magnetic resonance images in which the preliminary processing using thresholds in various image processings becomes easier, and reducing the imaging time in obtaining the SAS image of high contrast resolution and satisfactory three dimensional quality. In the apparatus, a predetermined imaging pulse sequence is carried out in order to obtain nuclear magnetic resonance image data; a nonlinear operation is applied on the nuclear magnetic resonance image data in order to obtain contrast enhanced image data; and an image given by the contrast enhanced image data is displayed.

Method and apparatus of nuclear magnetic resonance imaging with

An MRI system includes static and gradient field generators for respectively generating static and gradient fields to be applied to an object, a radio-frequency (RF) field transmitter/receiver for transmitting and receiving an RF field, a sequence controller for applying the gradient field and the RF field to the object at a predetermined timing while the object is being applied with the static field, thereby causing a predetermined MR phenomenon, a signal processor for performing predetermined processing of MR signal data detected through the RF field transmitter/receiver to obtain an MR image, and a display for displaying the image obtained by the signal processor. The sequence controller comprises a multi-slice controller for executing a multi-slice method using a sequence with a relatively long echo time so that an MR signal of a proton of a fat is suppressed and an MR signal of a proton of a CSF is emphasized. The signal processor comprises a summation processor for synthesizing multi-slice images as a plurality of slice images by summation to obtain a synthesized image.

Magnetic resonance imaging system

A magnetic resonance blood flow imaging method employs a field-echo technique and a gapless multi-slice acquisition technique in which a selective excitation pulse with a flip angle of less than 90 degrees is utilized and a pulse repetition time is set shorter than usual. Imaging data are acquired from multiple slices of a subject under examination while the multiple slices are shifted in sequence in position. A cross-sectional image is reconstructed for each of the multiple slices. Images obtained by performing subtractions on plural images for the same slice are gathered to thereby produce an image of blood vessels of the subject under examination which contain at least two blood vessels which run substantially in parallel and are opposite to each other in the direction of blood flow therein.

Method and apparatus for imaging blood vessels employing magnetic

In an MRI system, in order to acquire an MR image representing a brain surface anatomy of a head of a subject, a surface coil is disposed near the head of the subject, and a predetermined pulse sequence by a spin echo method, a field echo method, or the like is performed. A view direction is changed for a single slice, and an MR image based on stereoscopic viewing is obtained by a single scan. Regions of interest are set on the brain surface portion on the MR image, and then a predetermined pulse sequence is using an echo time for inhibiting mr signals from fat of the brain surface and using a pulse repetition time for enhancing mr signals from water of the brain surface in order performed to obtain projection data in a direction of depth, thereby allowing accurate grasping of the position of a disease portion.

Method and system for acquiring image representing brain surface anatomy

First and second MR (magnetic resonance) echo signals are detected from the subject by means of a spin echo method. These MR echo signals have been provided with different phase encoding data by applying the gradient magnetic fields. As a result, first and second MR echo signal data are acquired from a single Fourier plane. These MR echo signal data are amplitude-corrected and phase-corrected. Then, they are subjected to Fourier transform, thereby forming an MR image of the subject within a short time.

Method for detecting and processing magnetic resonance signals

A method and apparatus provides complete mensuration of two-dimensional Fourier components of a nuclear spin property thereby permitting undistorted image reconstruction. In spite of an unavoidable phase factor which originates from basic field inhomogeneities and drifts and from non-perfect electronics adjustment, an optimum sectional image is obtained from half measurements of the sampled resonance signals which are complex conjugate pairs. The image is obtained by determining the phase and then eliminating it from a spatial Fourier transform of the spin density distribution.

Method and apparatus for rapid NMR imaging

A quadrature detection circuit compensates for phase and amplitude differences in an NMR quadrature detection apparatus. The quadrature detection circuit comprises a test signal generator, first and second modulators, amplitude detectors, phase error detectors and a corrector. The corrector compensates the NMR signal as to phase and amplitude factors determined during an initial calibration mode utilizing the test signals, thus eliminating ghost images of the object which would otherwise be formed during image reconstruction.

Quadrature detection circuit for nuclear magnetic resonance apparatus

In the NMR apparatus the resonant conditions may be kept constant by adjusting the strength of the static magnetic field. The echo signal that is induced under the specific conditions is processed so as to obtain the deviation of the resonant frequency in the correction circuit. The shift of the given static magnetic field is calculated based upon the deviation of the resonant frequency. The DC energizing current for the H.sub.O power supply is varied based upon the magnetic field shift so as to maintain the NMR phenomenon at the desirable resonant conditions.

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Tochigi, Japan

Masahiko Hatanaka