Patent application number | Description | Published |
20090012385 | Magnetic Resonance Imaging Device and Method - A magnetic resonance imaging apparatus including signal receiving means for detecting a nuclear magnetic resonance signal from an object, signal processing means for reconstructing an image by using the detected nuclear magnetic resonance signal and display means for displaying the image, a whole image of the examiner being obtained while each imaging site of the object is continuously or stepwise moved and disposed in the imaging space, is equipped with detecting means for detecting the gradient and size of each site of the object, inputting means for inputting reference information for carrying out magnetic resonance imaging corresponding to the gradient and size of each site of the object onto an image representing the gradient and size of each site of the object which is displayed on the display means, storage means for storing the input reference information, control means for controlling the imaging operation on the basis of the reference information stored in the storage means, and combining means for combining nuclear magnetic resonance signals obtained through the imaging operation carried out under the control to create the whole image. | 01-08-2009 |
20090030302 | MAGNETIC RESONANCE IMAGING DEVICE - The magnetic resonance imaging apparatus includes a control unit for controlling a pulse sequence that applies an RF magnetic field and a magnetic field gradient to a subject placed in a static magnetic field and detects a magnetic resonance signal generated from the subject, and a calculation unit for processing the signal, and the control unit performs the process including the steps of; (1) obtaining first images at different positions in a first direction, (2) obtaining images after the first images are subjected to correction of brightness distortion, (3) obtaining images after the images as to which the brightness distortion has been corrected are further subjected to correction of positional distortion, and (4) synthesizing by a weighting calculation, overlapping areas of the images, after the positional distortion thereof has been corrected. According to this magnetic resonance imaging apparatus, the positional distortion and the brightness distortion can be corrected upon connecting the images, in the multi-station imaging. | 01-29-2009 |
20090066328 | Nuclear Magnetic Resonance Imaging Apparatus and Method - A control means controls an imaging means for taking an image of a test object by a magnetic resonance, the test object being placed in an imaging space, and a transfer means that moves the test object, and on the basis of a difference (moving distance) between a position of the transfer means at the time of receiving a command of pausing the imaging and a position of the transfer means at the time of resuming the imaging, the control means controls the position of the transfer means or the position for imaging at the time of resuming, in such a manner that missing of data | 03-12-2009 |
20090177078 | MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD - In the continuous moving table imaging, high-speed imaging such as the echo planar method is implemented without deteriorating image quality, realizing a high-speed table movement, namely, high-speed imaging. | 07-09-2009 |
20090278535 | Magnetic resonance imaging apparatus and method - In performing the moving table imaging, an MRI apparatus and a method thereof are provided, which minimizes image degradation and reduces imaging time. When an image of a wide range of a test object is taken, the imaging is repeated while changing the gradient magnetic field intensity in a phase-encode direction, as well as changing the size of field of view FOV in the readout direction by changing the readout gradient magnetic field intensity in reading out the data, according to the phase-encode amount. In a part where the FOV is expanded, data acquisition frequency is lowered, and consequently, the total imaging time is reduced. The data sampling time may be changed along with the change of the FOV, and therefore, a process for achieving a unique matrix size in the readout direction is rendered unnecessary, and a spatial resolution can be maintained. | 11-12-2009 |
20100013478 | MAGNETIC RESONANCE IMAGING DEVICE - A magnetic resonance imaging device includes magnetic field generating means and control means for controlling receiving means according to a predetermined pulse sequence, the predetermined pulse sequence including an unnecessary material suppressing sequence unit for canceling a signal from an unnecessary material which is not a measurement target and a main imaging sequence unit for measuring a nuclear magnetic resonance signal used to create an image of an examinee. The unnecessary material suppressing sequence unit generates at least two or more high frequency magnetic field pulses so that the longitudinal magnetization of the unnecessary material is made spatially uniform in the imaging space under application of a first high frequency magnetic field pulse in the main imaging sequence unit. The magnetic resonance imaging device further includes adjusting means for adjusting the flip angles of the two or more high frequency magnetic field pulses, and the control means applies the two or more high frequency magnetic field pulses at the flip angles adjusted by the adjusting means. | 01-21-2010 |
20100039110 | MAGNETIC RESONANCE IMAGING APPARATUS AND MAGNETIC RESONANCE IMAGING METHOD - An MRI apparatus capable of performing a high-speed operation for removing aliasing from the data measured by non-Cartesian imaging in a real space with a small amount of operation is provided. Non-Cartesian data sampling is performed by thinning the number of data by using multiple receiver coils having different sensitivity distribution from each other. Image reconstruction means creates orthogonal data by gridding non-orthogonal data obtained by each receiver coil on a grid having an equal spatial resolution to and a narrower field of view than a target image, subjects it to Fourier transform and creates the first image data containing aliasing components. The second image data is created by using the first image data created for each receiver coil and a sensitivity distribution of each receiver coil. | 02-18-2010 |
20100087729 | MAGNETIC RESONANCE IMAGING APPARATUS AND MAGNETIC RESONANCE IMAGING METHOD - When multiple types of imaging are performed while moving a table on which a subject to be examined is placed, an imaging efficiency is improved and a high-quality image is obtained within a short time. Therefore, within a predetermined time interval such as an identical period of a periodic living body motion, a predetermined number of echo signals from each of the multiple types of imaging sequences are acquired and the table on which the subject to be examined is placed is moved. Along with the movement of the table, data items within the same range in the Ky-direction as to each of the imaging sequences are acquired, the moving speed of the table is controlled in such a manner that the acquired data items become continuous in the x-direction, and images are reconstructed based on the data items obtained respectively from the imaging sequences. | 04-08-2010 |
20100141253 | MAGNETIC RESONANCE IMAGING APPARATUS - An MRI apparatus includes an imaging means being provided with a means for generating magnetic fields respectively of a static magnetic field, a gradient magnetic field, and an RF magnetic field, and a means for receiving an echo signal generated from a subject, the imaging means being for measuring echo data associated with at least one measurement trajectory in k-space, while varying angles with respect to a coordinate axis in the k-space of the measurement trajectory, so as to collect at least one measured data for each of the angles; and an image reconstruction means for rearranging the measured data in the k-space and reconstructing an image; wherein, the image reconstruction means calculates a phase for correction based on standard data selected from the measured data for each of the angles, prior to rearranging the measured data in the k-space, and performs a phase correction as to the measured data, by using the phase for correction being calculated. With the procedure above, it is possible to reduce an artifact caused by the nonlinearity of the gradient magnetic field and/or inhomogeneities of the magnetic field, without extending the imaging time. | 06-10-2010 |
20100156418 | MAGNETIC RESONANCE IMAGING APPARATUS AND MAGNETIC RESONANCE IMAGING METHOD - In order to stably obtain an even fat-suppressed image without reduction of an imaging efficiency and without being affected by unevenness of irradiation magnetic field of an RF pulse, when an imaging sequence having a first sequence part for suppressing a signal from a desired component of an examinee by applying a CHESS pulse and a second sequence part for measuring an echo signal from the examinee is repeated, the flip angle of the CHESS pulse is changed at plural times. In the case of multi-slice imaging, the flip angle of the CHESS pulse is changed in at lest two slice imaging. | 06-24-2010 |
20100164495 | MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD FOR CORRECTING ERROR DUE TO GRADIENT MAGNETIC FIELD - In a non-cartesian sampling method, in order to reduce an artifact on an image caused by an error of a gradient magnetic field, data for correcting the error caused by the gradient magnetic field are obtained when data used for image reconstruction are obtained, and the data used for the image reconstruction are corrected by using the obtained data for the correction. In order to obtain the data for correcting the error, a block having plural parallel echo signals is measured. | 07-01-2010 |
20100219828 | MAGNETIC RESONANCE IMAGING APPARATUS - A magnetic resonance imaging apparatus comprises object placing means for placing an object in an imaging space, translating means for translating the object in a given direction by translating the object placing means in the given direction continuously or step-wise, magnetic field generating means for exciting the desired region of the object by generating a static magnetic field, a gradient magnetic field in the imaging space, and a high-frequency magnetic field in the imaging space, signal detecting means for detecting a magnetic resonance signal from the object, and control unit for controlling the translating means, magnetic field generating means and the signal detecting means, and translating the object continuously or stepwise to a predetermined position at a predetermined speed so as to capture a magnetic resonance image of the object. | 09-02-2010 |
20100244823 | MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD - A magnetic resonance imaging apparatus comprising static magnetic field generating means for generating a static magnetic field in an imaging space, measuring means for generating a high-frequency magnetic field and a gradient magnetic field in the imaging space and measuring a nuclear magnetic resonance signal generated from an object to be examined placed in the imaging space, signal processing means for reconstructing a magnetic resonance image according to the nuclear magnetic resonance signal, control means for controlling the measuring means and the signal processing means, and display means for displaying the reconstructed magnetic resonance image obtained by the signal processing means. | 09-30-2010 |
20100253347 | ANTENNA SYSTEM AND MAGNETIC RESONANCE IMAGING APPARATUS - An RF coil is provided with a hollow-shaped outer conductive element and strip-shaped conductive elements disposed along the outer conductive element in the axial direction. The strip-shaped conductive elements are disposed with uneven intervals to secure an internal space at a position where the strip-shaped conductive elements are not disposed. In order to obtain uniform sensitivity at the center section of the RF coil, the strip-shaped conductive elements and the outer conductive element are electrically connected via capacitors of which capacitances are adjusted so that a magnetic field component perpendicular to the center axis should be generated at a desired resonance frequency, and the strip-shaped conductive elements are axisymmetrically disposed with respect to the center axis of the outer conductive element. As a result, a comfortable examination space in a tunnel type MRI apparatus is achieved without increasing the manufacturing cost of the MRI apparatus. | 10-07-2010 |
20110064294 | MAGNETIC RESONANCE IMAGING APPARATUS AND BLOOD VESSEL IMAGE ACQUIRING METHOD - Plural blood vessels different in blood flow velocity are depicted with high image quality in blood vessel imaging using PC-MRA method. For this purpose, the present invention performs a measurement of an echo signal based on application of a positive-polarity flow encode pulse and a measurement of an echo signal based on application of a negative-polarity flow encode pulse on an examinee with each of plural phase encodes while varying the flow encode, and a blood vessel image of the examinee is reconstructed by using the plural echo signals having different flow encode absolute values. | 03-17-2011 |
20110089948 | MAGNETIC RESONANCE IMAGING APPARATUS - An MRI apparatus includes an imaging means being provided with a means for generating magnetic fields respectively of a static magnetic field, a gradient magnetic field, and an RF magnetic field, and a means for receiving an echo signal generated from a subject, the imaging means being for measuring echo data associated with at least one measurement trajectory in k-space, while varying angles with respect to a coordinate axis in the k-space of the measurement trajectory, so as to collect at least one measured data for each of the angles; and an image reconstruction means for rearranging the measured data in the k-space and reconstructing an image; wherein, the image reconstruction means calculates a phase for correction based on standard data selected from the measured data for each of the angles, prior to rearranging the measured data in the k-space, and performs a phase correction as to the measured data, by using the phase for correction being calculated. With the procedure above, it is possible to reduce an artifact caused by the nonlinearity of the gradient magnetic field and/or inhomogeneities of the magnetic field, without extending the imaging time. | 04-21-2011 |
20110200243 | MAGNETIC RESONANCE IMAGING APPARATUS AND METHOD - Disclosed is a magnetic resonance imaging apparatus comprising static magnetic field generation means, gradient magnetic field generation means, high-frequency magnetic field generation means, reception means, signal processing means, and control means which controls the gradient magnetic field generation means, the high-frequency magnetic field generation means, the reception means, and the signal processing means, wherein said apparatus comprises: approximation means that approximates the output error of the gradient magnetic field using a combination of multiple parameter values with respect to each direction of the gradient magnetic field; evaluation means that evaluates the combinations of multiple parameter values based on the image quality of a magnetic resonance image that is reconstructed while taking into account the output error of the gradient magnetic field that has been approximated by the approximation means; and determination means that, based on the result of the evaluation by the evaluation means, determines a desired combination among the combinations of multiple parameter values. | 08-18-2011 |
20110245655 | MAGNETIC RESONANCE IMAGING APPARATUS AND PULSE SEQUENCE ADJUSTING METHOD - When executing an imaging pulse sequence using a high frequency magnetic field pulse with a partial waveform of a predetermined waveform, an application start time of a slice gradient magnetic field applied simultaneously with the high frequency magnetic field pulse is corrected. Specifically, a magnetic resonance signal for correcting the imaging pulse sequence is acquired by executing a prescan sequence using a high frequency magnetic field pulse with a predetermined waveform, an application start time of a slice selection gradient magnetic field in the imaging pulse sequence is corrected using the magnetic resonance signal for correction, and the imaging pulse sequence is executed by applying the slice selection gradient magnetic field with the corrected application start time. | 10-06-2011 |
20110267060 | MAGNETIC RESONANCE IMAGING DEVICE - A magnetic resonance imaging device includes magnetic field generating means and control means for controlling receiving means according to a predetermined pulse sequence, the predetermined pulse sequence including an unnecessary material suppressing sequence unit for canceling a signal from an unnecessary material which is not a measurement target and a main imaging sequence unit for measuring a nuclear magnetic resonance signal used to create an image of an examinee. The unnecessary material suppressing sequence unit generates at least two or more high frequency magnetic field pulses so that the longitudinal magnetization of the unnecessary material is made spatially uniform in the imaging space under application of a first high frequency magnetic field pulse in the main imaging sequence unit. The magnetic resonance imaging device further includes adjusting means for adjusting the flip angles of the two or more high frequency magnetic field pulses, and the control means applies the two or more high frequency magnetic field pulses at the flip angles adjusted by the adjusting means. | 11-03-2011 |
20120141007 | MAGNETIC RESONANCE IMAGING APPARATUS AND SYNCHRONOUS MEASUREMENT METHOD - An image with a desired contrast is obtained while suppressing body motion artifacts caused by both random motion and periodic motion of an object. In order to do so, an imaging sequence using a non-Cartesian sampling method is executed so as to synchronize with a biological signal only at the start time and a repetition time (TR), which is an execution interval between shots within the imaging sequence, is maintained. In addition, a time difference between a delay time and a start time of each shot is calculated, and a shot with a predetermined time difference or more is executed again after the TR time. | 06-07-2012 |
20120262173 | HIGH-FREQUENCY COIL UNIT AND MAGNETIC RESONANCE IMAGING DEVICE - There is provided a technique for securing a large examination space in a tunnel type MRI device without inviting increase of manufacturing cost and without significantly reducing irradiation efficiency or uniformity of the irradiation intensity distribution in an imaging region. Between rungs of a partially cylindrical RF coil, which coil corresponds to a cylindrical RF coil of which part is removed, there are disposed half-loops generating magnetic fields, which are synthesized with magnetic fields generated by loops constituted by adjacent rungs of the partially cylindrical RF coil and rings connecting the rungs to generate a circularly polarized or elliptically polarized magnetic field. Further, high-frequency signals of the same reference frequency having a desired amplitude ratio and phase difference are supplied to the partially cylindrical RF coils and half-loops. | 10-18-2012 |
20120299594 | ANTENNA DEVICE - There is provided a technique for securing a comfortable examination space in a tunnel type MRI apparatus without increasing the manufacturing cost of the MRI apparatus and sacrificing performance thereof. In an RF coil provided with a hollow-shaped outer conductive element and a strip-shaped conductive element disposed along the outer conductive element in the axial direction, meander lines constituting the strip-shaped conductive element are disposed at uneven distances from the outer conductive element to secure an internal space. In order to obtain uniform sensitivity at the center of the RF coil, the strip-shaped conductive element is constituted with N of connected meander lines, and length of the strip-shaped conductive element is adjusted so that, in the strip-shaped conductive element resonating at resonance frequency of the antenna, nodes are formed in a number of (M+1)×N−1, wherein M is 0 or a natural number of 1 or larger. | 11-29-2012 |
20130049753 | MAGNETIC RESONANCE IMAGING APPARATUS - The present invention provides an image processing technique which enables various contrast control, by quantitatively handling a degree of phase enhancement in a contrast control as a post-processing of the image reconstruction. A complex operation is performed on each pixel value of a complex image obtained by an MRI, thereby generating an image with desired contrast. Intensity is controlled by increasing or decreasing the argument of the pixel value of each pixel by a constant amount, and the degree of phase enhancement is controlled by multiplying the phase (argument) of each pixel by a constant. | 02-28-2013 |
20130119991 | HIGH-FREQUENCY COIL AND MAGNETIC RESONANCE IMAGING DEVICE EMPLOYING SAME - 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. The partial cylindrical coil is provided with a partial cylindrical conductor, multiple first conductors substantially parallel with the central axis of the RF shield, multiple capacitors connecting both ends of the first conductors with the partial cylindrical conductor, and a second conductor adjacent to at least one of the ends of the first conductor. The partial cylindrical coils are respectively provided with high frequency signals having a desired amplitude ratio and phase difference, while a reference frequency thereof being identical. | 05-16-2013 |
20130207654 | MAGNETIC RESONANCE IMAGING APPARATUS, METHOD FOR CORRECTING MEASUREMENT-SPACE COORDINATES, AND IMAGE RECONSTRUCTION METHOD - In order to approximate the gradient magnetic field pulse waveform shape with high accuracy and improve the image quality at the time of imaging cross-section change or oblique imaging, an MRI apparatus of the present invention divides the waveform shape of the gradient magnetic field pulse into a plurality of sections, defines an approximation function for each section, and corrects the k-space coordinates at which the echo signal is arranged using the parameter of the approximation function. In addition, an optimal parameter of the approximation function of the waveform shape of the gradient magnetic field pulse is searched for using the measured signal. | 08-15-2013 |
20130221968 | ANTENNA DEVICE AND MAGNETIC RESONANCE IMAGING DEVICE - 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. | 08-29-2013 |
20140292334 | Magnetic resonance imaging equipment, high frequency magnetic field irradiation method and program - With minimizing extension of imaging time, the B | 10-02-2014 |