Abstract: A plurality of subject parameter maps are acquired at high speed. In addition to using an imaging sequence for generating both a gradient echo and a spin echo in a single imaging sequence, one or more parameters such as the longitudinal relaxation time T1 and the apparent transverse relaxation time T2* are calculated using the gradient echo and another parameter such as true transverse relaxation time T2 is calculated using the spin echo. When a value of one parameter is calculated, a value of the parameter calculated at the time of calculating the other parameter can be used.

Abstract: In a case where a subject parameter distribution is obtained using MRI, a magnetization transfer effect is suppressed such that the calculation accuracy of T1 and T2 of brain parenchyma can be improved and a variation in the T1 value of blood caused by the effect of blood flow can be reduced. In imaging for parameter estimation, a magnetization transfer effect is suppressed by using a high frequency magnetic field pulse having a narrow frequency band as an excitation pulse. In a case where the frequency band is narrow, the high frequency magnetic field pulse has a shape in which the excitation profile is similar to a Gaussian function. A rising portion of the shape is arranged in a field of view where the head is an imaging target.

Abstract: There is provided a technique for DWI measurement, in which MPG application is performed in many directions, that enables detection of presence or absence of body motion during imaging without prolongation of imaging time. A plurality of image groups each comprising 6 or more diffusion-weighted images selected from a plurality of diffusion-weighted images are created so the groups differ from one anther in one or more diffusion-weighted images included in each of the groups. Value of a predetermined diffusion index representing a characteristic amount of diffusion-weighted image is calculated for each image group from the diffusion-weighted images included in each image group. Value of a predetermined body motion index relating to body motion information is calculated from the value of the diffusion index for each image group. Presence or absence of body motion is determined for each image group on the basis of the value of the body motion index.

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: Provided is a technique capable of achieving safety and image quality at the same time in an MRI device using a transmission coil including plural channels. An SAR distribution is calculated, and an imaging parameter is determined for optimizing a radio frequency magnetic field distribution in an imaging region while suppressing a maximum value of an SAR to be equal to or smaller than a predetermined threshold value. The determined imaging parameter includes a radio frequency magnetic field parameter for specifying radio frequency pulses to be transmitted through each of the plural channels. The SAR distribution is calculated using a database that retains an electric field distribution of each of the plural channels for each subject model retained in advance.

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: A multichannel array coil of an MRI apparatus acheives both a wide sensitivity and low noise. An RF coil (array coil) is provided with a plurality of subcoils. Each of those subcoils is adjusted to be receivable of nuclear magnetic resonance signals, and also adjusted so that a part of current (first current) passing through one subcoil upon receipt of the signals flows into the other subcoil in the form of sub-current. A flowing direction of the first current is opposite to the flowing direction of the sub-current, and an electric field generated by the first current within a subject and an electric field generated by the first sub-current within the subject intensify each other in the space between a first loop coil unit and a second loop coil unit. Accordingly, noise correlation that is determined by an inner product of the electric fields is reduced, thereby achieving low noise.

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: To provide a technique for supporting diagnosis by reducing a user's time and effort in quantitative diagnosis using a quantitative value acquired by a medical image acquisition apparatus. A user is allowed in advance to select only desired diagnostic information from vast amounts of diagnostic information such as images and numerical values. Only the selected diagnostic information is presented to the user in a user-friendly mode. The diagnostic information is calculated by using a physical property value necessary for the calculation of the diagnostic information in question and calculation information such as arithmetic functions and variables, the physical property value and calculation information being stored in advance.

Abstract: A system is disclosed to simultaneously acquire a magnetic resonance angiography (MRA) image and a plurality of images in which the structure of a tissue other than a blood vessel can be ascertained without performing imaging for the MRA image, and to shorten a time of MR examination. Two or more kinds of physical property dependent images obtained from a nuclear magnetic resonance signal measured in accordance with a predetermined pulse sequence under a plurality of imaging conditions are combined using a predetermined combination function.

Abstract: A medical image diagnosis supporting apparatus includes a quantitative value reception unit that receives data of kinds of quantitative values obtained in advance at points in a region of a subject; a variable conversion unit that calculates kinds of intermediate information values dependent on the kinds of quantitative values at each of the points using the kinds of quantitative values at each of the points and kinds of variable conversion functions; and a diagnosis image calculation unit that calculates a diagnosis image for the region. The diagnosis image calculation unit sets a pixel value at each of the points in accordance with a combination of kinds of intermediate information values obtained at each of the points by the variable conversion unit or a combination of intermediate information values and kinds of quantitative values at the point and generates the diagnosis image.

Abstract: When imaging is performed by executing a pulse sequence on an MRI apparatus, silencing is realized with securing sufficient application amount of crusher without extending the application time thereof. In the pulse sequence carried by the MRI apparatus, at least one gradient magnetic field pulse included in the pulse sequence has a waveform synthesized from two or more base waves shifting along the time axis direction (synthesized waveform), and the base waves have a smoothly changing waveform convex upward. The pulse of the synthesized waveform is generated from one or more trapezoidal or triangular base pulses by a waveform conversion part of a computer of the MRI apparatus or an external computer.

Abstract: In a multi-channel array coil used as an RF coil of an MRI apparatus, even when magnetic coupling occurs between the respective sub-coils, it is possible to suppress the influence of a current flowing through the sub-coil of a coupling counterpart to maintain the desired sensitivity and suppress deterioration of image quality. Therefor, even when magnetic coupling occurs between sub-coils constituting the multi-channel array coil used as the RF coil of the MRI apparatus, the sub-coils are connected to a signal processing circuit so that a phase difference between a rotating magnetic field generated by the influence of a current flowing through the sub-coil of the coupling counterpart and a rotating magnetic field generated by the sub-coil is less than 90 degrees.

Abstract: Restriction on echo intervals is to be reduced in the Dixon's method without sacrificing separation performance and image quality. An image is reconstructed from echo signals measured at three or more different echo times. First and second peak frequency distributions in which aliasing (folding) due to echo time intervals is removed are calculated from the obtained images, and the first and second peak frequency distributions are used to obtain an offset frequency distribution. Note that these first peak frequency distribution and second peak frequency distribution are a distribution of peak frequencies obtained on the assumption that all of the pixels are the first substance and a distribution of peak frequencies obtained on the assumption that all of the pixels are the second substance, respectively. The offset frequency distribution and the obtained images are used to separate an image of the first substance from an image of the second substance.

Abstract: When an electrical characteristic of a predetermined region of a subject placed in a static magnetic field space is measured by using magnetic resonance signals measured from the region, measurement data measured by coinciding direction of a tissue structure of the subject with the direction of the static magnetic field, and measurement data measured with a direction of the tissue structure of the subject crossing the direction of the static magnetic field are used. A rotating magnetic field map of the region is created from the measurement data, and the electrical characteristic is calculated by using the rotating magnetic field map. The electrical characteristic is calculated as an electrical characteristic including anisotropy by using information about the direction of tissue structure.

Abstract: In an MRI apparatus, an imaging that produces almost no sound is implemented without extending an imaging time, not only for three-dimensional imaging, but also for two-dimensional imaging. A gradient pulse in a pulse sequence provided in the MRI apparatus is adjusted by using a basic waveform having a distribution of frequencies where strength dwindles substantially as the frequency increases from zero, and the waveform is convex upward or downward varying smoothly. An application time and strength are adjusted so that almost no sound is produced. Any imaging executable by a conventional pulse sequence can be implemented without producing almost any sound, using the conventional pulse sequence with little change.

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: There is provided an MRI apparatus in which, when a quantitative value, which does not depend on imaging parameter values, is computed from a plurality of image data having different pixel values that are acquired by performing imaging the plurality of times with different imaging parameter values in the same pulse sequence, pixel values which are acquired from the imaging parameter values are predicted for each of a plurality of predetermined quantitative-value candidate group, and an initial value of the quantitative value is selected from the quantitative-value candidate groups with reference to the predicted pixel values. The optimal quantitative value is computed through a localized optimization technique using the selected initial value.

Abstract: There is provided a technique for DWI measurement, in which MPG application is performed in many directions, that enables detection of presence or absence of body motion during imaging without prolongation of imaging time. A plurality of image groups each comprising 6 or more diffusion-weighted images selected from a plurality of diffusion-weighted images are created so the groups differ from one anther in one or more diffusion-weighted images included in each of the groups. Value of a predetermined diffusion index representing a characteristic amount of diffusion-weighted image is calculated for each image group from the diffusion-weighted images included in each image group. Value of a predetermined body motion index relating to body motion information is calculated from the value of the diffusion index for each image group. Presence or absence of body motion is determined for each image group on the basis of the value of the body motion index.