Abstract: In calculating a local magnetic field distribution caused by a magnetic susceptibility difference between living tissues, using MRI, a local frequency distribution with a high SNR is calculated in a short computation time. Multi-echo complex images obtained by measurement of at least two different echo times using the MRI are converted into low-resolution images. A global frequency distribution caused by global magnetic field changes and an offset phase distribution including a reception phase and a transmission phase are separated from a phase distribution of the low-resolution multi-echo complex images. Thus calculated global frequency distribution and the offset phase distribution are enhanced in resolution. A local frequency distribution of each echo is calculated from the measured multi-echo complex images, the high-resolution global frequency distribution, and the high-resolution offset phase distribution.

Abstract: A technique in a medical imaging apparatus being capable of setting any plane in three-dimensional space as an imaging slice is provided, allowing an automatically-set imaging slice to be configured to suit user's preferences, and determine a position of the imaging slice being configured, with respect to an imaging target subject automatically with a high degree of accuracy. Reference information for specifying the imaging slice, set by the user for each imaging site, is associated with the anatomical feature of the imaging site, so as to generate an imaging slice parameter. Upon actual imaging, the imaging slice parameter and the anatomical feature of the imaging target subject obtained by scout imaging are used to determine the imaging slice position of the imaging target subject.

Abstract: Accuracy degradation due to a signal loss is reduced, and susceptibility is calculated with high accuracy where, by using an MRI, at least one echo is acquired where spatial magnetic field inhomogeneity is reflected, and a complex image is calculated from the acquired echo. Three masks are calculated from the calculated complex image; a low-signal region mask representing a low signal region, a first high-signal region mask representing a high signal and high fat content region, and a second high-signal region mask representing a high signal and low fat content region. In calculating a susceptibility image from a frequency image or a magnetic field image generated from the complex image, the susceptibility image is obtained under the constraint that a region defined by the low-signal region is set as a background and the susceptibility of the region defined by the second high-signal region mask is set to a specific value.

Abstract: The present invention provides a technique for obtaining a high-quality image at high speed in DKI analysis. In the DKI analysis, upon estimating a parameter relating to diffusion in an application direction of an MPG pulse, a least square fitting is separated from a constraint processing, and only a value of the pixel that does not meet the constraint condition in the least square fitting is targeted for the correction. Then, with regard to this pixel, a diffusion-related parameter is re-estimated using the pixel value after the correction, and a parameter image is generated by using the diffusion-related parameter thus obtained.

Abstract: Provided is a technique in calculating a magnetic susceptibility distribution by using an MRI, for reducing artifacts and noise and improving precision in the magnetic susceptibility distribution being calculated. According to this technique, a magnetic field distribution is obtained via a phase image from a complex image acquired through MRI. Under the constraint based on a relational expression between the magnetic field and the magnetic susceptibility, smoothing process is performed iteratively on the magnetic susceptibility distribution calculated from the magnetic field distribution. Specifically, a minimization process for minimizing through the iterative operation, an error function defined by a predetermined initial magnetic susceptibility distribution and the magnetic field distribution is performed, thereby calculating the magnetic susceptibility distribution.

Abstract: A magnetic resonance imaging apparatus comprising a measurement parameter-setting unit for setting measurement parameters that determine the strength and timing of the high frequency magnetic field and the gradient magnetic field, and a measuring unit for applying the high frequency magnetic field and the gradient magnetic field on a subject placed in the static magnetic field according to the measurement parameters and detecting the nuclear magnetic resonance signal generated from the subject as a complex signal. The measurement parameter-setting unit is equipped with: a basic parameter-inputting section for setting the imaging parameters and imaging cross-section; a limiting condition-inputting section for setting limiting conditions that apply limits on the setting of the voxel size; a voxel size-calculating section for setting the voxel size according to the limiting conditions; and a voxel size-displaying section for displaying the set voxel size to the user.

Abstract: Provided is a technique in calculating a magnetic susceptibility distribution by using an MRI, for reducing artifacts and noise and improving precision in the magnetic susceptibility distribution being calculated. According to this technique, a magnetic field distribution is obtained via a phase image from a complex image acquired through MRI. Under the constraint based on a relational expression between the magnetic field and the magnetic susceptibility, smoothing process is performed iteratively on the magnetic susceptibility distribution calculated from the magnetic field distribution. Specifically, a minimization process for minimizing through the iterative operation, an error function defined by a predetermined initial magnetic susceptibility distribution and the magnetic field distribution is performed, thereby calculating the magnetic susceptibility distribution.

Abstract: Provided is a magnetic resonance measuring apparatus that records measurement data measured by MRS or the like and a periodic motion of the measurement object during the measurement of the measurement data in association with each other, and classifies spectra calculated from the measurement data in accordance with a time phase of the periodic motion. Created spectra are integrated for each classification to thereby create partially integrated spectra, correction based on a relationship between the periodic motion and a phase fluctuation or a frequency fluctuation is performed on the partially integrated spectra, and the corrected partially integrated spectra are synthesized.

Abstract: A technique in a medical imaging apparatus being capable of setting any plane in three-dimensional space as an imaging slice is provided, allowing an automatically-set imaging slice to be configured to suit user's preferences, and determine a position of the imaging slice being configured, with respect to an imaging target subject automatically with a high degree of accuracy. Reference information for specifying the imaging slice, set by the user for each imaging site, is associated with the anatomical feature of the imaging site, so as to generate an imaging slice parameter. Upon actual imaging, the imaging slice parameter and the anatomical feature of the imaging target subject obtained by scout imaging are used to determine the imaging slice position of the imaging target subject.

Abstract: There is provided a technique for obtaining temperature information for inside of a living body and accuracy information thereof in short time with low burden imposed on a subject. It is realized with a spectrum calculator configured to perform MRS or MRSI measurement for two kinds of substances showing difference of resonant frequencies and calculating spectra of magnetic resonance signals of the two kinds of substances, a temperature information calculator configured to calculate temperature information for inside of the subject on the basis of peaks of the calculated spectra, a temperature accuracy information calculator configured to calculate temperature accuracy information indicating accuracy of the temperature information on the basis of peaks of the calculated spectra, and a display information generator configured to generate display information to be displayed on a display device on the basis of the temperature information and the temperature accuracy information.

Abstract: The estimation accuracy of a magnetic susceptibility value of tissue is improved by computing an edge image which represents the edge of the tissue on a magnetic susceptibility distribution and to reduce background noise without lowering the magnetic susceptibility value of the tissue. The present invention computes an absolute value image and a phase image from a complex image obtained by MRI, from the phase image, computes a low frequency region magnetic susceptibility image in which background noise is greater than a desired value, computes an edge information magnetic susceptibility image and computes a high frequency region magnetic susceptibility image, computes an edge mask from the edge information magnetic susceptibility image, smooths a magic angle region from the edge mask and the low frequency region magnetic susceptibility image and finally smooths a high frequency region using the high frequency region magnetic susceptibility image.

Abstract: Systems and methods for magnetic resonance imaging, including adjusting spatial distribution of a rotating magnetic field. By minimizing imaging time, the B1 nonuniformity reducing effect of RF shimming is maximized for an imaging section of an arbitrary axis direction and an arbitrary position. B1 distributions are measured for only several sections of one predetermined direction, and a radio frequency magnetic field condition that maximizes the B1 non-uniformity reducing effect for an imaging section of an arbitrary direction and an arbitrary position is calculated from the B1 distribution data.

Abstract: Disclosed is a magnetic resonance imaging apparatus that calculates a susceptibility map using a weighting image that reflects a phase variation with high accuracy. The weighting image is calculated from a phase image obtained from a complex image obtained by MRI. First, a region used in calculation of the phase variation is set as a calculation region, and then, a standard deviation or a variance of pixel values of the phase image in the calculation region is set as the phase variation. Further, the phase variation is converted into a weight that monotonically decreases in a broad sense as the phase variation increases to obtain the weighting image.

Abstract: An object of the present invention is to suppress artifacts generated by correction of spectral distortion induced by eddy currents in MRI devices with a simple method, and thereby improve accuracy of the correction.

Abstract: A technique is provided to reserve large examination space in the tunnel type MRI apparatus, without increasing production cost nor reducing significantly irradiation efficiency and homogeneity in an irradiation distribution within an imaging region. The present invention provides an RF coil unit in which four partial cylindrical coils are placed with a gap therebetween in the circumferential direction inside a cylindrical RF shield, in such a manner that two pairs of the partial cylindrical coils are opposed to each other, and magnetic fields produced by the individual partial cylindrical coils are combined, thereby producing a circularly polarized wave field or an elliptically polarized wave field.

Abstract: There is provided a technique for suppressing increase of SAR without sacrificing sensitivity in RF coils used in MRI apparatuses. The present invention provides an antenna device comprising a sheet-shaped conductor and a ribbon-shaped conductor disposed on the subject side with respect to the sheet-shaped conductor with a predetermined distance from the sheet-shaped conductor. The ribbon-shaped conductor has a meandering shape, and is adjusted so as to resonate at transmission and reception frequencies, and it is constituted so that distance to the sheet-shaped conductor becomes smaller at both end part thereof along the static magnetic field direction compared with the distance to the sheet-shaped conductor at the center thereof. Moreover, the ribbon-shaped conductor is constituted so as to have a smaller width, as the distance to the sheet-shaped conductor becomes smaller.

Abstract: The present invention is directed to an elliptical birdcage coil which reduces time and effort upon manufacturing and production cost, with less variations in performance. There is provided a high frequency coil unit made up of the elliptical birdcage coil having plural capacitors arranged at least on either of the ring conductors and the rung conductors, the capacitance of the plural capacitors being uniform with respect to each conductor type on which the capacitors are placed. In this elliptical birdcage coil, a value of inductance and arrangement of the ring conductors and the rung conductors are determined in such a manner that the capacitance of the capacitors becomes identical with respect to each conductor type on which the capacitors are arranged.

Abstract: In order to improve image quality, a technique for obtaining information for eliminating distortions of the k-space in the readout direction and the phase encoding direction caused by the waveform distortion of the gradient magnetic field pulse is provided. A pulse sequence for the main scan is used to repeatedly measure echoes with changing the time integral value of the dephasing pulse for the readout gradient magnetic field. In the above measurement, the phase encoding pulse is not made zero, but two-dimensional data are measured in the same manner as that of the main scan. By using the measured two-dimensional data, correction information for eliminating distortions of the k-space in the readout direction and the phase encoding direction caused by the waveform distortion of the gradient magnetic field pulse is calculated in each of the readout direction and the phase encoding direction.

Abstract: To provide a technique for sufficiently eliminating magnetic coupling between RF coils and improving image quality when a multi-element multi-tuned RF coil is used as a receive RF coil for an MRI device. In the invention, each of RF coils which constitute a multi-element multi-tuned RF coil which is used as a receive RF coil for an MRI device is provided with an inter-coil magnetic coupling prevention circuit which resonates at each frequency to which each RF coil is tuned and provides a high impedance. The inter-coil magnetic coupling prevention circuit adjusts an inductor and a capacitor so that both of a circuit on the side of a pre-amplifier viewed from both ends of a signal reception circuit and a circuit on the side of the signal reception circuit viewed from both ends of a serial resonance circuit connected to the pre-amplifier resonate at a plurality of frequencies to which the respective RF coils are tuned.

Abstract: Images of two or more kinds of substances showing different chemical shifts, such as water image and metabolite image, are obtained without extending measurement time. For example, images of two or more kinds of desired substances showing different chemical shifts, such as water image and metabolite image, are obtained by one time of execution of an imaging sequence. In this execution, a pre-pulse is applied so that signals of the substances to be separated shift on the image, and magnetic resonance signals are received with receiver RF coils in a number not smaller than the number of types of the substances to be separated. An image reconstructed from the magnetic resonance signals is separated into images of the individual substances using sensitivity maps of the receiver RF coils. Then, correction is performed for returning the shifted image to the original position.