Abstract: An NMR imaging method and apparatus according to the present invention which enables a reduction in the scanning time without lowering the contrast resolving power and the spatial resolving power is arranged such that data which belongs to a relatively low spatial frequency region is collected by an ordinary scanning method, while data which belongs to a relatively high spatial frequency region is collected by a scanning method which enables data to be collected at a relatively high frequency, and reconstruction of an image is effected on the basis of data synthesized from data collected by these two methods.

Abstract: An NMR imaging method and apparatus according to the present invention which enables collection of data to be effected within a minimum scanning time which can be desired for each object of inspection is arranged such that projection data concerning the object is collected from a plurality of directions, a direction in which the number of samples in the warp direction is minimized is obtained on the basis of the collected projection data, and then the scanning coordinate system is rotated in accordance with the obtained direction to collect data on the basis of the Fourier transformation method.

Abstract: A method of simultaneously correcting distortion in density due to uneven sensitivity of receiving coils, and location dependent phase distortion inherent in the system, wherein a phantom is scanned to determine echo signals, which echo signals are subjected to 2-dimensional inverse Fourier transformation, to obtain an image (Cij) and stored as it is in the form of a complex number, then the object to be examined is measured by similar operation to obtain an image (Oij) and wherein the image (Oij) is divided by computation with image (Cij) as follows .vertline.Sij.vertline.=.vertline.Oij.vertline./.vertline.Cij.vertline., by which equation computation is made to correct for density distortion, and wherein the angle of deviation is set as follows arg [Sij]=arg[Oij]-arg[Cij].ident.0, by which equation computation is made to correct for phase distortion.

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: An object which can provide a reference for measuring the intensity of a primary magnetic field, is positioned in the vicinity of a subject being examined. A variation in the primary magnetic field intensity is detected, based on a frequency shift of data observed of the object, and is used to control the primary magnetic field intensity, or reference frequency for phase detection, or to correct image data. In this manner image quality is prevented from being degraded due to the variation of the primary magnetic field intensity.

Abstract: An NMR data processing method for use with an NMR tomograph, wherein signals, located in a period before and after an NMR signal to be sampled and containing substantially none of the NMR signal component, are measured as offset data for each view, so that even the offset slightly fluctuating in the view can be corrected for the NMR signal, on the basis of that data.

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.