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: 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 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.

Abstract: A technology of improving image quality of a calculation image or parameter estimation accuracy even in a case where a method of simultaneously generating calculation images of a plurality of parameters is used is provided. Thus, by utilization of a reconstructed image in an optimal resolution of each parameter to be estimated, a value of the parameter is estimated and a calculation image that is a distribution of the value of the parameter is acquired. A reconstructed image in an optimal resolution is acquired by adjustment of a resolution of a reconstructed image acquired in an optimal resolution of an estimation parameter with the highest optimal resolution among parameters to be estimated in scanning. Alternatively, in scanning, only a reconstructed image used for calculation of a predetermined parameter to be estimated is acquired in an optimal resolution of the parameter to be estimated.

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: 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: A technique for improving accuracy of temperature measurement in a living body using MRS/MRSI is provided. A cerebrospinal fluid suppression sequence that does not affect nuclear magnetic resonance signals of metabolite, but suppresses nuclear magnetic resonance signals of cerebrospinal fluid is executed in advance of execution of a signal measurement sequence for measuring nuclear magnetic resonance signals of water and a desired metabolite. There are thereby obtained spectra of water and the metabolite obtained from the nuclear magnetic resonance signals of water and the metabolite in which nuclear magnetic resonance signals of cerebrospinal fluid is suppressed. The obtained spectral peaks are fitted to a model function to obtain resonant frequencies of water and the metabolite, and the difference thereof is used to calculate temperature.

Abstract: B1 distribution is calculated in a short time with a high degree of precision, and a high quality image is obtained. In the RF shimming for irradiating electromagnetic waves using an RF coil having multiple channels, the absolute values of subtraction images between multiple reconstructed images are used to calculate a transmitting sensitivity distribution which is necessary for calculating inter-channel phase difference and amplitude ratio of RF pulses provided to the respective channels. Those multiple reconstructed images are obtained by executing the imaging sequence after applying a prepulse at different flip angles respectively. Assuming an image obtained with a minimum flip angle as a reference image, for instance, the subtraction images are created between the reference image and the other respective images. It is also possible that multiple subtraction images being obtained are divided by one another, and the transmitting sensitivity distribution is created on the basis of the division result.

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: A quantitative image (resonance frequency map) of a resonance frequency difference is obtained using a high-speed phase compensated pulse sequence of a gradient echo (GE) system. A signal function of the pulse sequence used when obtaining the resonance frequency map is generated by a numerical simulation. The high-speed phase compensated pulse sequence uses a BASG sequence, for example.

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: 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, in a medical imaging apparatus enabling imaging of an arbitrary plane in a three-dimensional space, enabling automatic calculation of a slice position and automatic calculation of an extracting slice in MPR, without prolonging examination time. Two-dimensional scout scan similar to that used for manual setting of a slice position is performed, and the obtained scout images are processed to calculate a recommended slice position. Algorithms for the processing and various image processing procedures used for the processing are stored beforehand for every type of imaging region and every type of examination.

Abstract: A magnetic resonance imaging apparatus is provided, which is capable of reducing SAR while maintaining S/N ratio and image contrast in a GrE-type pulse sequence, regardless of whether a synchronous imaging is performed or not. The present invention controls a flip angle as to each measurement set 409 that is obtained by division according to the size of phase encoding and a body motion cycle of a subject in the GrE-type pulse sequence. In a set 501 which measures echoes with phase encoding having a minimum absolute value, the flip angle is maximized as to the RF pulse having a minimum phase encoding amount and at least one RF pulse irradiated immediately before. As for the other RF pulses, the flip angle varies within a range less than the maximum, irrespective of the non-imaging mode, the imaging mode, or the size of phase encoding.

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: In the diffusion-weighted imaging, amounts of distortion and amounts of phase offset of k-space data due to a temporally changing magnetic field error induced by eddy currents and vibrations associated with application of a diffusion-weighted gradient magnetic field pulse are corrected with good precision to improve image quality. Characteristic data for correcting distortion of k-space data are calculated for every position in the slice direction as peak shifts of projections observed between the cases of applying and not applying an MPG pulse. As the characteristic data, amounts of distortion in the read-out direction and the phase encoding direction and phase offset amounts in a slice plane are calculated.

Abstract: B1 distribution is calculated in a short time with a high degree of precision, and a high quality image is obtained. In the RF shimming for irradiating electromagnetic waves using an RF coil having multiple channels, the absolute values of subtraction images between multiple reconstructed images are used to calculate a transmitting sensitivity distribution which is necessary for calculating inter-channel phase difference and amplitude ratio of RF pulses provided to the respective channels. Those multiple reconstructed images are obtained by executing the imaging sequence after applying a prepulse at different flip angles respectively. Assuming an image obtained with a minimum flip angle as a reference image, for instance, the subtraction images are created between the reference image and the other respective images. It is also possible that multiple subtraction images being obtained are divided by one another, and the transmitting sensitivity distribution is created on the basis of the division result.

Abstract: In the continuous moving table imaging, an image is reconstructed with suppressed artifacts even in imaging under inhomogeneity of static magnetic field. In a magnetic resonance imaging apparatus, signals are measured with moving a table to obtain multiple data sets, and inverse Fourier transform of each data set is carried out in the read-out direction to obtain hybrid data. One-dimensional data are extracted from each hybrid data at a border with respect to the adjacent hybrid data, and correction values for corrections of discontinuity of signal intensity and phase at a border of hybrid data are obtained by using the one-dimensional data. Data obtained by inverse Fourier transform of each hybrid data are corrected by using the correction values, and an image showing continuity for signal intensity and phase is eventually obtained.

Abstract: There is provided a technique for, in a medical imaging apparatus enabling imaging of an arbitrary plane in a three-dimensional space, enabling automatic calculation of a slice position and automatic calculation of an extracting slice in MPR, without prolonging examination time. Two-dimensional scout scan similar to that used for manual setting of a slice position is performed, and the obtained scout images are processed to calculate a recommended slice position. Algorithms for the processing and various image processing procedures used for the processing are stored beforehand for every type of imaging region and every type of examination.