Abstract: A method and a system for magnetic resonance imaging using echo planar method enable obtaining MRI images reduced in ghost artifacts. The magnetic resonance imaging system realizing the magnetic resonance imaging method includes a gradient coil for fast switching (inverting) a gradient magnetic field in a magnetostatic field applied to an object to be analyzed by a magnetostatic field generator, a receiver for receiving magnetic resonant signals from atomic nuclei of the object to be analyzed as echo signals necessary for filling a k-space, k-space data developer for developing the signals converted into a digital form over the a k-space as echo data, data collector for collecting echo data of the same phase encoding data in two frequency encoding directions for about half the k-space, and imager for making an image by classifying the echo data by frequency encoding direction, performing Fourier transformation separately to obtain images, and adding absolute number processed images to improve S/N.

Abstract: An X-ray computerized tomography apparatus having an X-ray tube or detector constantly rotated an around an object for acquiring data during specific phase segments of the motion of the object. A period h and a phase are detected from R waves of an electrocardiogram. Searching is then done through a table to provide delay time d, measuring time e, rotating time k (being an integer not a multiple of period h), and counts n corresponding to the period h to the expression below:k=(h-e)/(1-M);wherein M is (0.ltoreq.M<1). n is obtained as an integer greater than k/(h-k). In operation, while the tube or detector is continuously rotated over k, X-rays are emitted at d. Data is measured during e, at the end of which the emission of X-rays is stopped. This is repeated as often as n until image reconstruction is acquired.

Abstract: A data collection method for MR angiography, wherein the scans resulting in spin warp values are assigned into groups of two or more consecutive acquisitions and each group is averaged two or more times for each heart beat period, whereby data collection time is reduced concurrently with suppression of motion artifacts, all without use of additional hardware.

Abstract: An MRI apparatus applies an exciting pulse R1 and a slicing gradient S1 which excites a slice S. Subsequently, it applies a diffusion sensitizing gradient MPG1. Next, it applies a reversing pulse R2 and an FOV limiting gradient RS which limits the data collecting region to have a narrow FOV. Next, it applies a diffusion sensitizing gradient MPG2. Next, it applies a positive and negative reading gradients RA and RB m times alternately and cyclically, and collects MR data from the multiple imaged echoes el.about.em, while applying phase encoding gradients W. The phase encoding gradient W has its amplitude-time product set to be 1/(.gamma..multidot.FOV), where .gamma. is the magnetogyric ratio. The apparatus produces a diffusion sensitized image at a practical spatial resolution, with artifacts attributable to the body movement being alleviated in exchange for a narrow FOV in the phase encoding axis direction.

Abstract: The method for restricting a region for magnetic resonance imaging, in accordance with the present invention, comprisinga step of measuring a spin-echo signal from an object by a pulse sequence of Fourier transformation technique;a step of measuring a spin-echo signal from an object by a pulse sequence comprising adding a selective 180.degree..+-.x pulse and a selective 180.degree..+-.y pulse following a 180.degree. pulse in the pulse sequence of Fourier transform technique, the integral of gradient magnetic fields for selection thereof being 0; anda step of reconstructing an image from the addition or subtraction between the spin-echo signals measured by the two sequences.

Abstract: An improved selective excitation method applicable to NMR imaging, regardless of the NMR signal generation method used, wherein a non-scanned subject area is excited using an RF signal, then the excited area is spoiled with a gradient magnetic field to create an area that receives no other excitation RF signal for a set period, and then NMR signals are collected from the unspoiled area using a conventional method.

Abstract: This invention concerns an X-ray CT image processing apparatus capable correcting the bone-induced beam hardening only based on the reconstructed image data at a high speed and simply, in which the bone region of the reconstructed image is discriminated based on the reconstructed image data, a correcting image data is determined through the masked addition or convolution of a 2-dimensional weight function using thus discriminated bone region as a mask and the correcting image data are added to the reconstructed image data.

Abstract: A method and apparatus are disclosed for nuclear magnetic resonance imaging utilizing the Fourier transform imaging scan sequence, with measurement data being obtained from which the offects of variations in the static magnetic field are eliminated. The method and apparatus are characterized by measurement of view data G(k,t) for a body which is under diagnosis under the condition that there is a specific value of twist of spin phase within the body, in a specific direction, measurement of the view data G(-k,t) for the body which is under diagnosis under the condition that the value of twist of the spin phase within the body is equal in amount and of opposite direction to the aforementioned value of twist of spin phase, with the time which elapses between the measurements of G(k,t) and G(-k,t) being made sufficiently short that any change in the static magnetic field occurring therein can be ignored, deriving from the view data G(k,t) and G(-k,t) the data G(k,t.sub.0) and G(-k,-t.sub.

Abstract: After spins in a subject being examined have been selectively excited, the application of gradient magnetic fields is interrupted to produce an FID signal. The intensity of the primary magnetic field is determined based on the central frequency of the Fourier spectrum of the FID signal, i.e., the Larmor frequency. The primary magnetic field is controlled or the observed data is corrected, according to the measured value of the primary magnetic field intensity.