Abstract: A first pulse sequence is executed on an imaging portion of an object to be examined using a multiple receiving coils including a plurality of receiving coils to obtain sensitivity images 701 to 703, each of n in number, which is smaller than the number of examination image. When those sensitivity images are calculated, NMR signals are measured only in a low-frequency region of a k space. Next, a second pulse sequence is executed while phase encoding steps are thinned out to acquire examination images 704 and 705, each of m in number (m>n), of the object with each receiving coil.

Abstract: An MRI system is realized which can always take an image under optimum conditions following the concentration of a contrast agent injected into a body and changed at every moment with time in the body, thereby obtaining a blood vessel image with higher quality even in a zone of a measurement period other than the time when the concentration of the injected contrast agent is peaked. A flip angle is changed following a contrast agent concentration b(t) as indicated by a curve 102. During a period Da in which the contrast agent concentration b(t) is gradually increased, a flip angle FA is increased following the contrast agent concentration b(t). During a period Db in which the contrast agent concentration b(t) is gradually decreased, the flip angle is gradually reduced.

Abstract: A magnetic resonance imaging method for fully automatically forming a water/fat separated image by calculation after acquiring data on images of different echo times, wherein the unwrapping of a phase map showing the distribution of the phase rotation due to the inhomogeneous static magnetic field is repeated so as to determine the distribution of the inhomogeneous static magnetic field by using an index used for judging whether or not the unwrapping is properly being performed, and wherein during the formation of a water/fat separated image with correction of the static magnetic field, the unwrapping is automatically and properly performed in correcting the static magnetic field, and the water/fat images are automatically discriminated.

Abstract: The present invention provides a magnetic resonance imaging system capable of performing spectrum measurement even when a magnetic resonant frequency changes during MRS measurement. A time-varying rate of a water magnetic resonant frequency is measured in advance before the MRS measurement. The amount of change in water magnetic resonant frequency during the MRS measurement is predicted from the measured time-varying rate. With the predicted value as the reference, a transmission frequency of an RF magnetic field irradiated in a signal suppression pulse sequence, a transmission frequency of an RF magnetic field for excitation and inversion and a received frequency at the detection of a magnetic resonance signal in a sequence of the MRS measurement are respectively set. A high-precision spectrum measurement is hence enabled.

Abstract: High-speed imaging by a propeller MRI method is enabled as a whole thanks to high-speed computation by preventing an aliasing artifact even if the echoes acquired by one blade are decreased and by reducing the imaging time and the computational complexity. In a magnetic resonance imaging apparatus, an RF pulse is applied to a subject placed in a static magnetic field, a plurality of gradient magnetic fields are applied, and induced nuclear magnetic resonance signal (echo signal) is received by means of a multiple RF receiving coil unit composed of two or more RF receiving coils. A parallel MRI method is applied to echo signals acquired by reducing the echoes per blade of a propeller MRI method so as to remove the artifact to produce a reconstructed image. The reconstructed image is subjected to inverse Fourier transform to return it to the echo signals in a measurement space corresponding to the blade. The echo signals are girded in an arbitrarily predetermined coordinate system for image and combined.

Abstract: A magnetic resonance imaging system in which measurement data (k space data) of arterial phase is extracted easily (and instantaneously) after imaging a plurality of time phases including the arterial phase and its image can be displayed in dynamic MRA measurement employing a contrast medium. Dynamic measurement is thereby carried out using a means for extracting the time phase evaluation values (e.g. the origin data in k space) in respective time phases and then automatically extracting a data set including a time phase where the time phase evaluation value reaches a specified threshold value.

Abstract: To provide a diagnostic apparatus utilizing nuclear magnetic resonance suitable for interventional MRI which is not limited as to selection of an imaging section and an phase-encoding axis, the reception coil thereof includes three loop coils arranged so as to surround an object to be examined and to be within a plane including a line segment parallel to a static magnetic field direction, and two surface coils arranged in the vicinity of the surface of the object within a plane including a line segment perpendicular to the static magnetic field direction. In the reception coil, two or more sub-coils have nonuniform sensitivity profiles along an arbitrary axis. Therefore, the reception coil configured to have sensitivity throughout the imaging areas can be realized.

Abstract: An MRI apparatus suitable for realizing selective excitation utilizing multiple RF transmitting coils (parallel transmission) is provided. This MRI apparatus is provided with, as an RF receiving coil or RF transmitting coil, an RF transmitting coil 104 comprising a loop coil 210, primary differential coil 220 and secondary differential coil 230 having a common central axis 201. Upon imaging, the coils 210, 220 and 230 constituting the RF transmitting coil 104 are simultaneously driven by RF signals with the same phase, and only the differential coils 220 and 230 are driven in the second half of irradiation time with phases different by 180° from the phases for the first half.

Abstract: A first pulse sequence is executed on an imaging portion of an object to be examined using a multiple receiving coils including a plurality of receiving coils to obtain sensitivity images 701 to 703, each of n in number, which is smaller than the number of examination image. When those sensitivity images are calculated, NMR signals are measured only in a low-frequency region of a k space. Next, a second pulse sequence is executed while phase encoding steps are thinned out to acquire examination images 704 and 705, each of m in number (m>n), of the object with each receiving coil.

Abstract: When data of plural original images having different echo times are acquired to produce water/fat separated images by performing an processing operations in an MRI apparatus, a partial region of the original image data is specified and the specified region is subjected to the water/fat separation processing. Since noise components included in the specified region are fewer than those in the original image data, errors occurring due to noise components during unwrapping and other such processing operations can be reduced and image quality degradation be suppressed. Therefore, water/fat separated images having an excellent image quality can be produced. When echoes having different echo times are generated, rewind pulses are applied ahead of the readout gradient magnetic fields to equalize the polarities of the readout gradient magnetic fields. Consequently, influence of application of gradient magnetic fields on echo signals can be suppressed and the accuracy of water/fat separation can be improved.

Abstract: A magnetic resonance imaging apparatus has means for detecting the movement of an object so as to correct the variation of the non-uniformity of static magnetic field because of the movement of the object and thereby to improve the quality of the MR image. When actually measured data is corrected by using a signal for correcting the static magnetic field obtained in a preliminary measurement, the influence of the non-uniformity of static magnetic field is eliminated from the image based on the information from the body movement detecting means by using a correcting signal measured at the same time phase of the periodic movement as that of the actually measured signal. A navigation echo measured during the same repetition time as that of the actually measured signal is used for detection of time phase by detecting means.

Abstract: A magnetic resonance imaging apparatus includes a magnetic field generation means for applying gradient magnetic fields and a radio-frequency magnetic field to a patient placed in a static magnetic field in a predetermined pulse sequence; a multiple RF receiving coil comprising at least three RF receiving coils for receiving the nuclear magnetic resonance signals generated from the patient; and an image reconstruction means for reconstructing an image by processing the received nuclear magnetic resonance signals, wherein the image reconstruction means includes a coil selection means for selecting a plurality of RF receiving coil groups that are preset by combining the plurality of RF receiving coils according to imaging conditions, a synthesization means for synthesizing the measured data received by the respective RF receiving coils of each of the plurality of selected RF receiving coil groups, and a calculation means for eliminating aliasing artifacts by executing a matrix calculation as to the synthesized

Abstract: A magnetic resonance imaging apparatus is provided with a sequencer for executing a rapid imaging sequence of up to 100 ms at a full scan, a parallel measurement system for executing a partial encoding measurement in which the number of phase encoding operations performed for the measurement is reduced, an image processing system for reconstructing images from the information obtained though parallel measurements and composing reconstructed images of a plurality of areas to make one image, a display system for displaying the obtained images at a rate of 50 frame/second or more, and an image renewal system for taking in coordinate information of the cross-section to be imaged from position and pointing devices at intervals of about 0.1 second, and renewing the cross-section to be imaged in real time. Thus, imaging on the cross-sections indicated by a device can be performed in real time with high spatial and high time resolution.

Abstract: A magnetic resonance imaging apparatus includes control means 107 and 108 for continuously performing magnetic resonance imaging of a cross section including a portion subjected to measurement of an examinee (101) at a predetermined time interval, operation means 108 for calculating diagnosis information related to the portion subjected to measurement by using a plurality of sets of nuclear magnetic resonance signals related to cross sections imaged at different time points by measuring nuclear magnetic resonance signals generated from the examinee 101, and a position detection device 118 having a detection camera 118b for detecting in non-contact manner the position (three-dimensional position and rotation angle around an orthogonal coordinate axis) of a pointer 118a provided outside the examines body and moving while interlocked with the biological movement of the examinee 101.

Abstract: An RF receiving means, which comprise respective at least three RF receiving coils (203, 201 (or 202), 204), (205, 202 (or 201), 206), (207, 201 (or 202), 208) disposed in at least two orthogonal directions (x, y, z), are set to a patient 209, any one direction (x) of the two directions is set as a phase encoding direction, magnetic resonance signals are measured by executing a pulse sequence while thinning phase encoding steps, and the aliasing of an image is eliminated by an arithmetic operation executed using the magnetic resonance signals measured by at least the three RF receiving coils (205, 202 (or 201), 206) disposed in the thus set phase encoding direction and using the sensitivity distributions of the respective RF receiving coils.

Abstract: An MRI apparatus is provided for obtaining an image of a wide area using a multiple-coil, where a plural number of small receiving coils are arranged such that adjacent coils overlap spatially. An image is picked up while thinning a part of the measured data, such that the low spatial frequency region of the k space is dense and the high spatial frequency region thereof is sparse. The substantial sensitivity distribution of each small receiving coil is determined using data related to the low spatial frequency region, and an image is composed using the sensitivity distribution and the measured data to produce a high resolution image having no aliasing artifact in a short time.

Abstract: A magnetic resonance imaging apparatus includes a magnetic field generation means for applying gradient magnetic fields and a radio-frequency magnetic field to a patient placed in a static magnetic field in a predetermined pulse sequence; a multiple RF receiving coil comprising at least three RF receiving coils for receiving the nuclear magnetic resonance signals generated from the patient; and an image reconstruction means for reconstructing an image by processing the received nuclear magnetic resonance signals, wherein the image reconstruction means includes a coil selection means for selecting a plurality of RF receiving coil groups that are preset by combining the plurality of RF receiving coils according to imaging conditions, a synthesization means for synthesizing the measured data received by the respective RF receiving coils of each of the plurality of selected RF receiving coil groups, and a calculation means for eliminating aliasing artifacts by executing a matrix calculation as to the synthesized

Abstract: A magnetic resonance imaging apparatus having control means for fetching a plurality of image data and obtaining an image by a calculation. The control means performs an unwrap processing to a plurality of regions for removing a main value of a phase rotation amount so as to obtain a distribution diagram of a phase rotation amount caused by magnetostatic unevenness, obtains a plurality of evaluation values based on the phase value between a plurality of regions, selects a desired evaluation values based on the phase value from the plurality of evaluation values, and adjusts the phase values between the regions in accordance with the desired evaluation value.

Abstract: An imaging sequence for MRI is performed to produce MR images of an object to be examined and display them on a monitor. Marks 6, 7 and 8 are defined at regions to be observed (observation regions), such as a bifurcation 3 and constriction 4 of the displayed image 1. If the distance between an invasive device 10 displayed in the image and the marks is within a predetermined range, at least one of the frame rate (reciprocal of an image-updating interval) and the spatial resolution is altered so as to automatically raise the imaging speed or so as to improve the spatial resolution when the invasive device reaches the observation region. The movement of the invasive device and its relationship to a blood vessel can therefore be finely monitored with high accuracy.

Abstract: In order to improve image quality in MRI using an EPI method without extending imaging time excessively, reference data is acquired in the absence of substantial phase encoding gradients by using an EPI sequence in combination with an echo shift (ETS) method, at times related to the timing of echo signals for image data. The reference data is used for phase correcting the image data acquired with application of phase encoding. The reference data can be measured for a single shot, or a few shots, and used to estimate reference data for the rest of the shots in which imaging data is acquired.