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: 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: 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: Acoustic noise reduction is achieved in a high-speed imaging method such as a phase-compensation type GE sequence, which is not provided with sufficiently long intervals for applying the gradient magnetic field pulses. A band-stop filter is used to reduce components of a frequency band in the gradient magnetic field waveform, having a high sound pressure level being a source of sound, thereby performing the noise reduction. In general, when a band of the gradient magnetic field is reduced, the waveform is likely to be considerably distorted, failing to satisfy imaging conditions. Therefore, the distorted waveform is shaped so that the imaging conditions are satisfied. The sound pressure level of the gradient magnetic field waveform is calculated by using a response function inherent to the device.

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: 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: 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.

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: 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: 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: There is provided a technique for obtaining a magnetic susceptibility-weighted image in which contrast difference of a tissue of interest and a surrounding tissue can be emphasized regardless of the positional relationship of the B0 direction and the imaging slice. A phase image is converted into a susceptibility map not depending on the B0 direction, and then a weighting image used for weighting is generated by using the susceptibility map. The weighting image to be generated is for emphasizing contrast of a tissue of interest and a surrounding tissue depending on the purpose. Then, by multiplication of the weighting image and an absolute image, a magnetic susceptibility-weighted image in which the magnetic susceptibility difference is emphasized depending on the purpose is obtained.

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: In the diffusion spectroscopic imaging, in which intensity of molecular diffusion is imaged with separating chemical substances, with suppressing artifacts resulting from object motion of an object, spatial resolution, spectral band and SNR are maintained, and measurement accuracy is enhanced. A measurement for acquiring diffusion SI data is repeated a plurality of times with changing acquisition timing, phase variation of each measurement result is corrected, and a diffusion SI image is reconstructed from the corrected measurement results. In addition, the phase variation is calculated for every point in the space from the diffusion SI data acquired by each measurement or navigation data obtained by each measurement. The phase correction is independently performed for every point in the space.

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: 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: 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: 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. In the eddy current correction processing for correcting spectral distortion caused by an eddy current using phase values of FID signals of a substance showing higher signal intensities compared with a metabolite as an object of measurement, phase jumps of the phase values used for the correction are corrected beforehand. In the correction of the phase jumps, small phase change amount points are identified by using primary time differential values of the phase values, and the other points are identified as a phase jump generation region. Then, the primary time differential values corresponding to the identified phase jump generation regions are excluded.

Abstract: There is provided a technique for obtaining a magnetic susceptibility-weighted image in which contrast difference of a tissue of interest and a surrounding tissue can be emphasized regardless of the positional relationship of the B0 direction and the imaging slice. A phase image is converted into a susceptibility map not depending on the B0 direction, and then a weighting image used for weighting is generated by using the susceptibility map. The weighting image to be generated is for emphasizing contrast of a tissue of interest and a surrounding tissue depending on the purpose. Then, by multiplication of the weighting image and an absolute image, a magnetic susceptibility-weighted image in which the magnetic susceptibility difference is emphasized depending on the purpose is obtained.

Abstract: Water/fat separation imaging is performed by an MRI device, even if the measurement is not performed with such echo times that the phases of water and fat signals become in-phase or out-of-phase. A determination is made as to which of two obtained separation images is a water image or a fat image. Two water/fat ratio maps are calculated from two original images obtained with such two echo times that phase differences of water and fat signals do not become positive and negative values, and do not becomes integral multiples of ?. Two phase maps are calculated from the two water/fat ratio maps and are combined to calculate two minimum phase difference maps showing minimum spatial phase difference. From dispersion in differential maps obtained by spatially differentiating the minimum phase difference maps, a correct minimum phase difference map is determined, and is used to perform phase correction of the original image.