JP2018110848A - 磁気共鳴イメージング装置 - Google Patents
磁気共鳴イメージング装置 Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/58—Calibration of imaging systems, e.g. using test probes, Phantoms; Calibration objects or fiducial markers such as active or passive RF coils surrounding an MR active material
- G01R33/583—Calibration of signal excitation or detection systems, e.g. for optimal RF excitation power or frequency
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/4816—NMR imaging of samples with ultrashort relaxation times such as solid samples, e.g. MRI using ultrashort TE [UTE], single point imaging, constant time imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/483—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy
- G01R33/4833—NMR imaging systems with selection of signals or spectra from particular regions of the volume, e.g. in vivo spectroscopy using spatially selective excitation of the volume of interest, e.g. selecting non-orthogonal or inclined slices
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/565—Correction of image distortions, e.g. due to magnetic field inhomogeneities
- G01R33/56572—Correction of image distortions, e.g. due to magnetic field inhomogeneities caused by a distortion of a gradient magnetic field, e.g. non-linearity of a gradient magnetic field
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/565—Correction of image distortions, e.g. due to magnetic field inhomogeneities
- G01R33/5659—Correction of image distortions, e.g. due to magnetic field inhomogeneities caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field
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- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
- Optics & Photonics (AREA)
- Spectroscopy & Molecular Physics (AREA)
Abstract
【解決手段】磁気共鳴イメージング装置は、シーケンス制御部と、算出部とを備える。シーケンス制御部は、複数のRF(Radio Frequency)パルスを印加してエコーを生成する第1のパルスシーケンスと、RFパルスを印加してデータ収集を行う第2のパルスシーケンスとを実行する。算出部は、第1のパルスシーケンスにおけるエコーのピーク位置の測定値と、第1のパルスシーケンスにおけるエコーのピーク位置の理論値との時間差を算出し、時間差に基づいて、第2のパルスシーケンスにおけるRFパルスの有効励起時間を算出する。
【選択図】図5B
Description
142 MRIデータプロセッサ
Claims (9)
- 複数のRF(Radio Frequency)パルスを印加してエコーを生成する第1のパルスシーケンスと、RFパルスを印加してデータ収集を行う第2のパルスシーケンスとを実行するシーケンス制御部と、
前記第1のパルスシーケンスにおける前記エコーのピーク位置の測定値と、前記第1のパルスシーケンスにおける前記エコーのピーク位置の理論値との時間差を算出し、前記時間差に基づいて、前記第2のパルスシーケンスにおける前記RFパルスの有効励起時間を算出する算出部とを備える磁気共鳴イメージング装置。 - 前記複数のRFパルスは、実質的に同じ時間幅、振幅、波形形状、およびフリップ角を有する、請求項1に記載の磁気共鳴イメージング装置。
- 前記シーケンス制御部は、前記第1のパルスシーケンス及び前記第2のパルスシーケンスにおいて、前記RFパルスの印加から前記データ収集までの間一定の振幅の傾斜磁場を更に印加する、請求項1に記載の磁気共鳴イメージング装置。
- 前記複数のRFパルスは、1対のRFパルスである、請求項1に記載の磁気共鳴イメージング装置。
- 前記シーケンス制御部は、前記第1のパルスシーケンスを、複数回実行し、
前記算出部は、複数回実行された前記第1のパルスシーケンスにおいて生成された複数の前記エコーのピーク位置の測定値と、複数回実行された前記第1のパルスシーケンスにおいて生成された複数のエコーのピーク位置の理論値とに基づいて、前記有効励起時間を算出する、請求項1に記載の磁気共鳴イメージング装置。 - 前記シーケンス制御部は、前記第1のパルスシーケンスの実行のたび、前記複数のRFパルスの印加間隔を一定の時間だけ増やしながら、前記第1のパルスシーケンスを複数回実行する、請求項5に記載の磁気共鳴イメージング装置。
- 前記算出部は、複数回実行された前記第1のパルスシーケンスにおいて生成された複数の前記エコーのピーク位置の測定値と、複数回実行された前記第1のパルスシーケンスにおいて生成された複数の前記エコーのピーク位置の理論値との間で線形フィッティングを行って、前記有効励起時間を算出する、請求項5に記載の磁気共鳴イメージング装置。
- 前記複数のRFパルスは、3個以上のRFパルスである、請求項1に記載の磁気共鳴イメージング装置。
- 前記第2のパルスシーケンスは、ZTE(Zero Time Echo)シーケンスまたはPETRA(Pointwise Encoding Time Reduction with Radial Acquisition)シーケンスである、請求項1に記載の磁気共鳴イメージング装置。
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US15/401,749 US10416267B2 (en) | 2017-01-09 | 2017-01-09 | Apparatus and method for calibration of time origin of an RF pulse in MRI data acquisition systems |
US15/401,749 | 2017-01-09 |
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JP2018110848A true JP2018110848A (ja) | 2018-07-19 |
JP6991848B2 JP6991848B2 (ja) | 2022-01-13 |
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Citations (3)
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JP2000279396A (ja) * | 1999-03-22 | 2000-10-10 | General Electric Co <Ge> | 磁気共鳴イメージング・システムにおける較正方法及びシステム |
JP2004154399A (ja) * | 2002-11-07 | 2004-06-03 | Ge Medical Systems Global Technology Co Llc | 群遅延最適化方法および磁気共鳴撮影装置 |
US20150066413A1 (en) * | 2013-09-04 | 2015-03-05 | Samsung Electronics Co., Ltd. | Method for correcting errors associated with asynchronous timing offsets between transmit and receive clocks in mri wireless radiofrequency coils |
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DE4334038C1 (de) * | 1993-10-06 | 1995-03-23 | Bruker Medizintech | Geräuscharmes NMR-Bildgebungsverfahren mit Einzelpunktaufnahme (SPI) |
US5672969A (en) * | 1996-04-25 | 1997-09-30 | General Electric Company | Reduction of Nyquist ghost artifacts in oblique echo planar imaging |
US6188219B1 (en) * | 1999-01-22 | 2001-02-13 | The Johns Hopkins University | Magnetic resonance imaging method and apparatus and method of calibrating the same |
US6933720B2 (en) * | 2001-12-11 | 2005-08-23 | Toshiba America Mri, Inc. | Sequence preconditioning for ultra-fast magnetic resonance imaging |
WO2006121827A2 (en) | 2005-05-06 | 2006-11-16 | Board Of Regents, The University Of Texas System | System, program product, and method of acquiring and processing mri data for simultaneous determination of water, fat, and transverse relaxation time constants |
EP2063282B1 (en) | 2007-11-22 | 2013-01-16 | Kabushiki Kaisha Toshiba | MR imaging of flowing matter using steady state free precession |
JP5718655B2 (ja) | 2010-04-30 | 2015-05-13 | 株式会社東芝 | 磁気共鳴イメージング装置 |
US8717023B2 (en) * | 2011-04-21 | 2014-05-06 | Mark Griswold | Relaxometry quantification self-justification fitting |
WO2014024085A2 (en) | 2012-08-08 | 2014-02-13 | Koninklijke Philips N.V. | Multiple shot magnetic resonance imaging with ghosting stability correction |
DE102012218424B3 (de) | 2012-10-10 | 2014-03-20 | Siemens Aktiengesellschaft | Schnelle MR-Bildaufnahme mit optimiertem Signal-Rausch-Verhältnis und/oder Kontrast |
RU2660401C1 (ru) | 2013-12-02 | 2018-07-06 | Конинклейке Филипс Н.В. | Магниторезонансная томография с использованием последовательностей импульсов с нулевым временем эхо |
CN107110938B (zh) | 2014-11-14 | 2019-12-17 | 皇家飞利浦有限公司 | 使用具有额外180度rf脉冲的自旋回波脉冲序列的磁共振指纹 |
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Publication number | Priority date | Publication date | Assignee | Title |
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JP2000279396A (ja) * | 1999-03-22 | 2000-10-10 | General Electric Co <Ge> | 磁気共鳴イメージング・システムにおける較正方法及びシステム |
US6288545B1 (en) * | 1999-03-22 | 2001-09-11 | General Electric Company | Method and apparatus for calibration of RF and gradient field time delays |
JP2004154399A (ja) * | 2002-11-07 | 2004-06-03 | Ge Medical Systems Global Technology Co Llc | 群遅延最適化方法および磁気共鳴撮影装置 |
US20150066413A1 (en) * | 2013-09-04 | 2015-03-05 | Samsung Electronics Co., Ltd. | Method for correcting errors associated with asynchronous timing offsets between transmit and receive clocks in mri wireless radiofrequency coils |
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US10416267B2 (en) | 2019-09-17 |
JP6991848B2 (ja) | 2022-01-13 |
US20180196115A1 (en) | 2018-07-12 |
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