Abstract: In order to eliminate the degradation of NMR image caused by a body motion due to breathing or the like, one of measured image signals is selected as a reference, correlation is calculated between each measured image signal and the reference, and the image signal is modified on the basis of the value of correlation.

Abstract: A magnetic resonance imaging apparatus selects a partial region of a slice in a subject with a radio frequency magnetic field and generates echo signals only from the partial region. The echo signals are collected from the subject by using an ultra-high speed data acquisition technique. An image of a partial region is reconstructed from the echo signals.

Abstract: Based on the relation that the higher the temperature of a portion to be measured, the lower becomes coherence of a nuclear spin at that portion, the present invention measures indirectly the temperature state of the portion to be measured from the change of intensity of NMR signals by utilizing this relationship. A transverse relaxation time is contained as one of the parameters in the relation between the signal intensity and the temperature; hence this transverse relaxation time is determined in advance for the portion to be measured and utilized in for the equation representing their relationship. This application discloses also an invention for determining a blood perfusion rate of the portion to be measured from the temperature data obtained in the manner described above.

Abstract: Disclosed is an automated image gray level transformation system applied to a medical image processing work station for the purpose of dispensing with the prior art manual complex processing thereby improving the accuracy of diagnosis. The system carries out, in addition to its fundamental step of equalizing a histogram of image data of an input image, the steps of suppressing an adverse effect of a background region of the image so as to obtaining an intensity transformation function, constraining the intensity transformation function and modifying a bias value used for the function constraining.

Abstract: To obtain a high quality image at a vascular area at high speed: (1) there is used a pulse sequence which includes a bipolar phase encoding magnetic field, dephases a stationary area, and does not generate the first order moment; (2) phase distortions are estimated from measured data and removed, without incorporating a new function for function fitting; and (3) the relationship between the application timing of a readout gradient magnetic field and the latest application time of the other slice selection and phase encoding magnetic fields is obtained using as its parameter the time T.sub.E from excitation to generation of an echo peak within a measurement signal, and using this relationship, the application timing T.sub.E is obtained which makes minimum the echo peak shift quantity.

Abstract: In one aspect of correcting phase distortion in an MR imaging system at high speed and with high precision, partial regions having any shapes are established on a complex image reconstruction, linear phase distortion is estimated for every partial region and the phase distortion of the whole image is corrected by use of the estimated phase distortion. In another aspect, a plurality of phase distortion patterns are measured in advance through phantom imaging and stored. The phase distortion pattern is invariable and hence it is not necessary to perform the measurement for each impage processed. Phase distortion included in data acquired through imaging is corrected by representing it as a summation of the plurality of phase distortion patterns with weighting factors.

Abstract: There is provided an image noise reduction method for improving the signal-to-noise ratio of an image when observed. The image signal of an identical region is measured twice at different times. Images obtained by respective measurements and seen from an identical visual point are so juxtaposed on an identical plane as to form two sheets. By seeing the two sheets of images with parallax changed directly or through stereo glass, the effective signal components of the images are focused on the same plane whereas only noise components are dispersed in a direction perpendicular to the plane.

Abstract: In order to eliminate the degradation of NMR image caused by a body motion due to breathing or the like, one of measured image signals is selected as a reference, correlation is calculated between each measured image signal and the reference, and the image signal is modified on the basis of the value of correlation.

Abstract: An MRI method is disclosed, by which, when liquid moving in a body to be examined stays in a predetermined region, this region is excited by using the nuclear magnetic resonance phenomenon and when the liquid thus excited moves from that excited region, a nuclear magnetic resonance signal produced by the excited spin and emitted during the relaxation time thereof is detected.

Abstract: To display the information, as an image, regarding the moving portion of the object without the aid of the doctor, the image is reconstructed on the basis of the observed NMR signal and the image phase information is calculated from the image intensity information derived from the reconstructed image, and the phase information calculated is displayed as the image.

Abstract: An image reconstruction method for a magnetic resonance imaging device is disclosed, by which phase distortions of a magnetic resonance signal are stored in the form of a table prepared previously, by using a phase encode amount and an imaging region size as parameters; the phase distortions of the magnetic resonance signal are corrected on the basis of the phase distortions stored in the table for the measured magnetic resonance signal or the phase distortions varying for every line are presumed from the difference in the phase between the phase of hypothetical data including no phase distortions and the phase of measured data; and the phase distortions of the measured magnetic resonance signal are corrected by using this presumed value.

Abstract: A magnetic resonance signal is detected at a plurality of different periods of time in accordance with the phase shift of a plurality of chemical shift components while varying the intensity of a gradient magnetic field with time, a plurality of magnetic resonance signal thus obtained are used for estimating a magnetic resonance signal due to only a predetermined chemical shift component, the phase rotation of the predetermined chemical shift component is corrected in the estimated resonance signal, and further a blur due to chemical shift components other than the predetermined one is corrected to obtain a tomogram formed of only the predetermined chemical shift component. Alternatively, one measured resonance signal is modified by an image reconstruction algorithm peculiar to each of a plurality of chemical shift components, to obtain tomograms corresponding to the chemical shift components.

Abstract: A magnetic resonance image synthesizing system comprising a magnetic field generating section for generating a static magnetic field, a gradient magnetic field and a radio-frequency magnetic field and for irradiating those magnetic fields to an object to be examined, a receiver for detecting a magnetic resonance signal supplied from the object to be examined, a processing unit for calculating and constructing an MR image and distribution of blood velocity or relaxation time on the basis of the detected nuclear magnetic resonance signal, a sequence control section for controlling the gradient magnetic field and the radio-frequency magnetic field as well as the receiver, a display unit for displaying an MR image, and a manipulation section for specifying a necessary position on the screen of the display unit, the processing unit further making the display unit display an MR image calculated and synthesized on the basis of scanning parameters and a blood velocity or relaxation time defined in accordance with a p

Abstract: The blood flow imaging method excites selectively a partial region of the body to be tested including blood vessels inside or outside of the view field of image, measures resonance signals by utilizing spins flowing out of the excited region, and images a blood vessel system based on the blood flow information included in the measured resonance signals. The method images only blood vessels through a single shot of scanning, thereby reducing the time for scanning and enabling the observation of finer vessels.

Abstract: An MR imaging method comprising detecting resonant signals from a portion including blood vessels by the three-dimensional imaging incorporating depthwise information, and performing subtraction, with respect to the signal data in each voxel in the complex number representation, between the image data obtained by adding the complex numbers in the projection direction and the image data obtained by adding the absolute values of the complex numbers in the projection direction, to extract the image of only the blood vessel.

Abstract: In order to narrow the dynamic range of an NMR signal and to provide MRI of low cost and high image quality without inducing the distortions of an image other than distortion of phase which can be corrected or the degradations of the measurement accuracies of various parameters, a coil for generating an inhomogeneous magnetic field which varies slowly within region to-be-imaged is added to a coil for generating a static magnetic field of high homogeneity, and current to flow through the former coil is changed so as to control the inhomogeneous magnetic field.

Abstract: A sequence for detecting variations in the blood flow speed in the blood vessel is added before a measurement of imaging signals so as to determine the highest and/or the lowest speed points of time and an examined body is imaged two times at those timings. In this way the timing for setting the delay time measured from the R wave can be determined automatically and thus it is possible to obtain a blood vessel image of high quality in a short time with the minimum number of two images.

Abstract: A method of MR dynamic imaging comprises the steps of uniformly dividing one scan which is a minimum measurement unit in generating one image data into a plurality of cycles, sequentially extracting one-scan data which are staggered by a predetermined number of cycles, from a series of data derived by repeating the scan a plurality of times in such a manner that the measurement data in each cycle includes high frequency component and low frequency component of the image, and generating image data from the extracted data.

Abstract: An apparatus for improving the signal-to-noise ratio of a scan-type imaging system, in which an image portion which appears virtually periodically or regularly on contiguous scanning lines and a scanning line for which the improvement of signal-to-noise ratio is intended are specified using cursors, the positional differences on the image signal waveforms between the specified scanning line and scanning lines in the specified image portion are detected, and the image signal waveforms in the specified image portion are added by being shifted by the amount of detected positional differences, so that the signal-to-noise ratio of the image signal waveform of the specified scanning line is improved.

Abstract: In order to have the number of times of signal measurements in a phase encode direction or a readout direction and raise the speed of imaging, the following steps are performed by way of example:(i) For a measurement region E required by a conventional method, any desired partial region E.sup.+ is set (here, the combination between the region E.sup.+ and a region obtained by moving the region E.sup.+ in point symmetry with respect to the origin of a measurement space includes the region E).(ii) A signal h.sup.+ is measured on the region E.sup.+.(iii) An image is reconstructed from the signals h.sup.+ on a region neighboring the origin, thereby to obtain a phase image .theta..(iv) A reconstructed image is obtained by a predetermined computation employing .theta..