Patents by Inventor Aki Yamazaki
Aki Yamazaki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Magnetic resonance imaging apparatus and RF pulse for navigator and imaging sequence applying method
Patent number: 9316713Abstract: A magnetic resonance imaging apparatus includes a scan section for executing a navigator sequence which transmits an RF pulse to a subject to obtain each magnetic resonance signal as navigator data. Upon execution of the navigator sequence, the scan section excites both a navigator area having two regions from which intensities of different navigator data signals are obtained, the two regions containing a body-moved region of the subject, and a region different from the two regions simultaneously, and transmits the RF pulse in such a manner that the phase of navigator data obtained from the different region differs from the phase of at least one region of navigator data obtained from the two regions.Type: GrantFiled: April 23, 2009Date of Patent: April 19, 2016Assignee: General Electric CompanyInventors: Yuji Iwadate, Kenichi Kanda, Aki Yamazaki -
Publication number: 20090270720Abstract: A magnetic resonance imaging apparatus includes a scan section for executing a navigator sequence which transmits an RF pulse to a subject to obtain each magnetic resonance signal as navigator data. Upon execution of the navigator sequence, the scan section excites both a navigator area having two regions from which intensities of different navigator data signals are obtained, said two regions containing a body-moved region of the subject, and a region different from the two regions simultaneously, and transmits the RF pulse in such a manner that the phase of navigator data obtained from the different region differs from the phase of at least one region of navigator data obtained from the two regions.Type: ApplicationFiled: April 23, 2009Publication date: October 29, 2009Applicant: GE MEDICAL SYSTEMS GLOBAL TECHNOLOGY COMPANY, LLCInventors: Yuji Iwadate, Kenichi Kanda, Aki Yamazaki
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Patent number: 7564242Abstract: An MR data acquisition method for acquiring data D_?fat according to a steady-state pulse sequence specifying that a phase of an RF pulse is varied in order of 0, 1×?fat, 2×?fat, etc., wherein ?fat=(2?TR/T_out+2×m)×? is established on an assumption that m denotes an integer equal to or larger than 0 and meets TR/(2×T_out)?1<m<TR/(2×T_out) where TR denotes a repetition time and T_out denotes a time during which spins in water and spins in fat are out of phase with each other due to chemical shifts.Type: GrantFiled: March 17, 2008Date of Patent: July 21, 2009Assignee: GE Medical Systems Global Technology Company, LLCInventors: Mitsuharu Miyoshi, Aki Yamazaki
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Publication number: 20080157763Abstract: An MR data acquisition method for acquiring data D_?fat according to a steady-state pulse sequence specifying that a phase of an RF pulse is varied in order of 0, 1×?fat, 2×?fat, etc., wherein ?fat=(2?TR/T_out+2×m)×? is established on an assumption that m denotes an integer equal to or larger than 0 and meets TR/(2×T_out)?1<m<TR/(2×T_out) where TR denotes a repetition time and T_out denotes a time during which spins in water and spins in fat are out of phase with each other due to chemical shifts.Type: ApplicationFiled: March 17, 2008Publication date: July 3, 2008Inventors: Mitsuharu Miyoshi, Aki Yamazaki
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Patent number: 7365537Abstract: An object of the present invention is to acquire data, which is used to construct a water component-enhanced/fat component-suppressed image, with a repetition time TR set to a desired value. Included are a data acquisition unit and an image construction unit. The data acquisition unit acquires data D_?fat according to a steady-state pulse sequence specifying that the phase of an RF pulse is varied in order of 0, 1×?fat, 2×?fat, etc. Herein, ?fat=(2?TR/T_out+2×m)×? is established on the assumption that m denotes an integer equal to or larger than 0 and meets TR/(2×T_out)?1<m<TR/(2×T_out) where TR denotes the repetition time and T_out denotes the time during which spins in water and spins in fat are out of phase with each other due to chemical shifts. The image construction unit constructs an MR image Gw using the data D_?fat.Type: GrantFiled: February 1, 2005Date of Patent: April 29, 2008Assignee: GE Medical Systems Global Technology Company, LLCInventors: Mitsuharu Miyoshi, Aki Yamazaki
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Patent number: 7323873Abstract: The present invention is intended to provide a phase error measuring method capable of measuring a phase error occurring in each phase encoding direction that corresponds to the direction of a readout magnetic field gradient which is turned in units of a radian. The phase error measuring method in accordance with the present invention is implemented in a magnetic resonance imaging (MRI) apparatus that performs a K-space filling scan to define data in a K-space having readout lines formed along a Kx axis, a Ky axis, and a mixed axis of them. The phase error measuring method includes a plurality of phase error measurement steps of measuring a phase error that occurs in each phase encoding direction corresponding to the direction of a readout magnetic field gradient which is turned in units of a radian.Type: GrantFiled: November 30, 2005Date of Patent: January 29, 2008Assignee: GE Medical Systems Global Technology Company, LLCInventor: Aki Yamazaki
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Publication number: 20060116569Abstract: The present invention is intended to provide a phase error measuring method capable of measuring a phase error occurring in each phase encoding direction that corresponds to the direction of a readout magnetic field gradient which is turned in units of a radian. The phase error measuring method in accordance with the present invention is implemented in a magnetic resonance imaging (MRI) apparatus that performs a K-space filling scan to define data in a K-space having readout lines formed along a Kx axis, a Ky axis, and a mixed axis of them. The phase error measuring method includes a plurality of phase error measurement steps of measuring a phase error that occurs in each phase encoding direction corresponding to the direction of a readout magnetic field gradient which is turned in units of a radian.Type: ApplicationFiled: November 30, 2005Publication date: June 1, 2006Inventor: Aki Yamazaki
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Publication number: 20050179432Abstract: An object of the present invention is to acquire data, which is used to construct a water component-enhanced/fat component-suppressed image, with a repetition time TR set to a desired value. Included are a data acquisition unit and an image construction unit. The data acquisition unit acquires data D_?fat according to a steady-state pulse sequence specifying that the phase of an RF pulse is varied in order of 0, 1×?fat, 2×?fat, etc. Herein, ?fat=(2?TR/T_out+2×m)×? is established on the assumption that m denotes an integer equal to or larger than 0 and meets TR/(2×T_out)?1<m<TR/(2×T_out) where TR denotes the repetition time and T_out denotes the time during which spins in water and spins in fat are out of phase with each other due to chemical shifts. The image construction unit constructs an MR image Gw using the data D_?fat.Type: ApplicationFiled: February 1, 2005Publication date: August 18, 2005Inventors: Mitsuharu Miyoshi, Aki Yamazaki
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Patent number: 6819104Abstract: An object of the present invention is to produce images devoid of band artifacts. Data acquisition in SSFP is repeated N times (where N denotes the power of 2) in order to acquire data fv(k), which ranges from data fv(0) to data fv(N−1), from views v constituting a k-space. At this time, the phase of an RF pulse is varied based on an expression of 360°·v·k/N. If an operator designates Fourier transform imaging, a Fourier transform is performed on data fv(k) relative to each of the phases indicated by the RF pulse in order to produce data Fv(n). If the operator does not designate Fourier transform imaging, the data fv(k) is regarded as the data Fv(n) as it is. Any of at least either of weighted addition and MIP processing and root-mean-square conversion selected by the operator is then performed on the data Fv(n) in order to produce data Av. An image is reconstructed based on the data Av.Type: GrantFiled: June 20, 2002Date of Patent: November 16, 2004Assignee: GE Medical Systems Global Technology Company, LLCInventors: Aki Yamazaki, Yoshihiro Oda, Naotaka Adachi
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Patent number: 6720767Abstract: For the purpose of obtaining an image without band artifacts, in a pulse sequence for conducting data collection in an SSFP state, the phase of an RF pulse &agr; is adjusted to correct the zeroth-order phase offsets of an FID signal and SE/STE signals and a correction pulse for correcting the first-order phase offsets of the FID signal and the SE/STE signals are incorporated into a read axis pulse.Type: GrantFiled: January 17, 2003Date of Patent: April 13, 2004Assignee: GE Medical Systems Global Technology Company, LLCInventor: Aki Yamazaki
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Patent number: 6664787Abstract: For the purpose of accurately measuring and correcting a phase error in spins in a phase axis direction, a gradient magnetic field having an integral value of zero is applied in the phase axis direction during a time period between first and second 180° excitations to read out a first spin echo SE1; a gradient magnetic field having an integral value of zero is applied in the phase axis direction during a time period between second and third 180° excitations to read out a second spin echo SE2; and a phase error due to an effect of residual magnetization Gp0 is determined based on these spin echoes.Type: GrantFiled: August 20, 2001Date of Patent: December 16, 2003Assignee: GE Medical Systems Global Technology Company, LLCInventors: Mitsuharu Miyoshi, Aki Yamazaki
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Publication number: 20030137298Abstract: For the purpose of obtaining an image without band artifacts, in a pulse sequence for conducting data collection in an SSFP state, the phase of an RF pulse &agr; is adjusted to correct the zeroth-order phase offsets of an FID signal and SE/STE signals and a correction pulse for correcting the first-order phase offsets of the FID signal and the SE/STE signals are incorporated into a read axis pulse.Type: ApplicationFiled: January 17, 2003Publication date: July 24, 2003Applicant: Aki YamazakiInventor: Aki Yamazaki
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Publication number: 20020196019Abstract: An object of the present invention is to produce images devoid of band artifacts. Data acquisition in SSFP is repeated N times (where N denotes the power of 2) in order to acquire data fv(k), which ranges from data fv(0) to data fv(N−1), from views v constituting a k-space. At this time, the phase of an RF pulse is varied based on an expression of 360°·v·k/N. If an operator designates Fourier transform imaging, a Fourier transform is performed on data fv(k) relative to each of the phases indicated by the RF pulse in order to produce data Fv(n). If the operator does not designate Fourier transform imaging, the data fv(k) is regarded as the data Fv(n) as it is. Any of at least either of weighted addition and MIP processing and root-mean-square conversion selected by the operator is then performed on the data Fv(n) in order to produce data Av. An image is reconstructed based on the data Av.Type: ApplicationFiled: June 20, 2002Publication date: December 26, 2002Inventors: Aki Yamazaki, Yoshihiro Oda, Naotaka Adachi
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Patent number: 6498485Abstract: In order to provide a gradient magnetic field application method and apparatus for preventing artifacts due to a magnetic field outside a field of view (FOV), and a magnetic resonance imaging apparatus employing such a gradient magnetic field application apparatus, in performing a plurality of RF excitations of spins of atomic nuclei within a subject to be imaged in the presence of a gradient magnetic field and producing an image based on magnetic resonance signals generated by the spins, at least the polarity of the gradient magnetic field in a first RF excitation (G90) and the polarity of the gradient magnetic field in the next RF excitation (G180) are made opposite to each other.Type: GrantFiled: April 21, 2000Date of Patent: December 24, 2002Assignee: GE Yokogawa Medical Systems, LimitedInventors: Mitsuharu Miyosi, Aki Yamazaki
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Patent number: 6489764Abstract: To preventing a deterioration in NMR signals due to a slice-leaned state, in executing a pulse sequence by the spin echo method, the inclination angle G2 of the slice gradient at the time of applying a 180° RF pulse P is made smaller than the inclination angle G1 of the slice gradient at the time of applying a 90° RF pulse R.Type: GrantFiled: February 8, 2001Date of Patent: December 3, 2002Assignee: GE Medical Systems Global Technology Company, LLCInventors: Aki Yamazaki, Yoshikazu Ikezaki
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Patent number: 6472873Abstract: The present invention provides selective excitation of a slab by RF signals of frequency compensated for in response to the error in the gradient magnetic field in the slice axis direction and phase encoding in the slice axis direction with the phase compensated for corresponding to the corrected frequency, in order to capture appropriate magnetic resonance signals in three dimensional scanning when there is an error in the slice gradient.Type: GrantFiled: July 24, 2001Date of Patent: October 29, 2002Assignee: GE Medical Systems Global Technology Company, LLCInventor: Aki Yamazaki
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Publication number: 20020101237Abstract: In order to provide a gradient magnetic field application method and apparatus for preventing artifacts due to a magnetic field outside a field of view (FOV), and a magnetic resonance imaging apparatus employing such a gradient magnetic field application apparatus, in performing a plurality of RF excitations of spins of atomic nuclei within a subject to be imaged in the presence of a gradient magnetic field and producing an image based on magnetic resonance signals generated by the spins, at least the polarity of the gradient magnetic field in a first RF excitation (G90) and the polarity of the gradient magnetic field in the next RF excitation (G180) are made opposite to each other.Type: ApplicationFiled: April 21, 2000Publication date: August 1, 2002Inventors: Mitsuharu Miyosi, Aki Yamazaki
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Publication number: 20020053906Abstract: The present invention provides selective excitation of a slab by RF signals of frequency compensated for in response to the error in the gradient magnetic field in the slice axis direction and phase encoding in the slice axis direction with the phase compensated for corresponding to the corrected frequency, in order to capture appropriate magnetic resonance signals in three dimensional scanning when there is an error in the slice gradient.Type: ApplicationFiled: July 24, 2001Publication date: May 9, 2002Inventor: Aki Yamazaki
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Publication number: 20020047708Abstract: For the purpose of accurately measuring and correcting a phase error in spins in a phase axis direction, a gradient magnetic field having an integral value of zero is applied in the phase axis direction during a time period between first and second 180° excitations to read out a first spin echo SE1; a gradient magnetic field having an integral value of zero is applied in the phase axis direction during a time period between second and third 180° excitations to read out a second spin echo SE2; and a phase error due to an effect of residual magnetization Gp0 is determined based on these spin echoes.Type: ApplicationFiled: August 20, 2001Publication date: April 25, 2002Inventors: Mitsuharu Miyoshi, Aki Yamazaki
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Publication number: 20010021795Abstract: To preventing a deterioration in NMR signals due to a slice-leaned state, in executing a pulse sequence by the spin echo method, the inclination angle G2 of the slice gradient at the time of applying a 180° RF pulse P is made smaller than the inclination angle G1 of the slice gradient at the time of applying a 90° RF pulse R.Type: ApplicationFiled: February 8, 2001Publication date: September 13, 2001Inventors: Aki Yamazaki, Yoshikazu Ikezaki