JPH0376134B2 - - Google Patents
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- Publication number
- JPH0376134B2 JPH0376134B2 JP63195390A JP19539088A JPH0376134B2 JP H0376134 B2 JPH0376134 B2 JP H0376134B2 JP 63195390 A JP63195390 A JP 63195390A JP 19539088 A JP19539088 A JP 19539088A JP H0376134 B2 JPH0376134 B2 JP H0376134B2
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- JP
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- Prior art keywords
- magnetic field
- coil
- subject
- correction
- static
- Prior art date
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- 238000002595 magnetic resonance imaging Methods 0.000 claims description 16
- 230000003068 static effect Effects 0.000 claims description 16
- 238000005481 NMR spectroscopy Methods 0.000 claims description 6
- 230000007613 environmental effect Effects 0.000 description 29
- 238000010586 diagram Methods 0.000 description 9
- 230000005540 biological transmission Effects 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000013480 data collection Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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- Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、磁気共鳴イメージング装置（以下、
MRI装置という。）に係わり、周囲の磁場環境変
動による画質劣化を防止するのに好適な磁場変動
抑制機構を備えたMRI装置に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic resonance imaging apparatus (hereinafter referred to as
It's called an MRI machine. ), and relates to an MRI apparatus equipped with a magnetic field fluctuation suppression mechanism suitable for preventing image quality deterioration due to fluctuations in the surrounding magnetic field environment.
従来のMRI装置は、その周囲を、高透磁率材
料で囲み、磁気シールドすることにより、周囲の
磁場環境変動を低減し、画像劣化を防止してい
た。
Conventional MRI devices are surrounded by high magnetic permeability materials to provide magnetic shielding, thereby reducing fluctuations in the surrounding magnetic field environment and preventing image deterioration.
しかしながら、前記従来のMRI装置では、広
い部分を磁気シールド材料で囲む必要があるた
め、大規模で、高価格の工事が必要となるという
問題があつた。
However, the conventional MRI apparatus has the problem of requiring large-scale and expensive construction work because it is necessary to surround a wide area with magnetic shielding material.
また、装置を設置した後に環境磁場を変動させ
るものが新設された場合には、その装置を搬出し
て工事しなおさなければならないという問題があ
つた。 Furthermore, if a new device that changes the environmental magnetic field is installed after the device has been installed, there is a problem in that the device must be removed and reworked.
本発明は、前記問題点を解決するためになされ
たものである。 The present invention has been made to solve the above problems.
本発明の目的は、容易でかつ安価な方法で環境
磁場変動の影響を低減することができる技術を提
供することにある。 An object of the present invention is to provide a technique that can reduce the influence of environmental magnetic field fluctuations in an easy and inexpensive manner.
本発明の他の目的は、環境磁場変動を正確にか
つ信頼性よく検出し、この検出値に基づいて環境
磁場変動の影響を正確に低減できる技術を提供す
ることにある。 Another object of the present invention is to provide a technique that can accurately and reliably detect environmental magnetic field fluctuations and accurately reduce the influence of environmental magnetic field fluctuations based on the detected values.
本発明の前記ならびにその他の目的と新規な特
徴は、本明細書の記述及び添付図面によつて明ら
かになるであろう。 The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.
このような目的を達成するために、本発明は、
基本的には、被検体が配置される所定の空間領域
内にほぼ均一な静磁場を形成する静磁場発生磁石
と、前記静磁場内の複数方向に傾斜磁場を発生す
る傾斜磁場発生手段と、前記被検体の特定断面に
おける磁場の強さで決定される周波数をもつ電磁
波を照射し前記特定断面内の組織を構成する原子
核に共鳴現象を起こさせる送信高周波コイルと、
該電磁波照射による核磁気共鳴信号を検出する受
信高周波コイルとを備える磁気共鳴イメージング
装置において、被検体の配置される前記空間内に
前記静磁場発生磁石とは別個に磁場補正コイルを
設けるとともに、装置の外部に磁場センサを配置
し、かつ、この磁場センサの磁場変動にともなう
出力により該変動分の磁場を相殺させる磁場を前
記磁場補正コイルに発生させる制御手段を備えた
ことを特徴とするものである。
In order to achieve such an objective, the present invention
Basically, a static magnetic field generating magnet that forms a substantially uniform static magnetic field in a predetermined spatial region in which a subject is placed, a gradient magnetic field generating means that generates gradient magnetic fields in multiple directions within the static magnetic field, a transmitting high-frequency coil that irradiates electromagnetic waves with a frequency determined by the strength of the magnetic field in a specific cross section of the subject to cause a resonance phenomenon in atomic nuclei constituting the tissue in the specific cross section;
A magnetic resonance imaging apparatus comprising a receiving high-frequency coil for detecting a nuclear magnetic resonance signal due to the electromagnetic wave irradiation, wherein a magnetic field correction coil is provided separately from the static magnetic field generating magnet in the space in which the subject is placed, and the apparatus A magnetic field sensor is disposed outside the magnetic field sensor, and a control means is provided for causing the magnetic field correction coil to generate a magnetic field that cancels out the variation of the magnetic field by the output of the magnetic field sensor due to the variation of the magnetic field. be.
前述の手段によれば、環境磁場変動を検出する
磁場センサが、装置近くに配置され、この磁場セ
ンサに発生する出力波形を増幅し、この出力波形
に応じた電流を磁場発生用コイルに流せば、必要
な空間内において環境磁場変動を打ち消すための
磁場を発生させることができる。それによつて環
境磁場が変動しても必要な空間内の磁場を安定に
保つことができる。
According to the above-mentioned means, a magnetic field sensor that detects environmental magnetic field fluctuations is placed near the device, the output waveform generated by this magnetic field sensor is amplified, and a current corresponding to this output waveform is passed through the magnetic field generating coil. , it is possible to generate a magnetic field to cancel out environmental magnetic field fluctuations within the required space. This makes it possible to maintain a stable magnetic field within the required space even if the environmental magnetic field fluctuates.
また、装置の外部に配置された磁場センサによ
つて、通常は微弱である磁場変動分のみを常時ピ
ツクアツプでき、この磁場変動で被検体が配置さ
れる空間内の磁場を正確かつ迅速に補償すること
ができるようになる。 In addition, the magnetic field sensor placed outside the device can always pick up only the normally weak magnetic field fluctuations, and this magnetic field fluctuation can accurately and quickly compensate for the magnetic field in the space where the subject is placed. You will be able to do this.
以下、本発明の一実施例を図面を用いて具体的
に説明する。
Hereinafter, one embodiment of the present invention will be specifically described using the drawings.
なお、実施例を説明するための全図において、
同一機能を有するものは同一符号を付け、その繰
り返しの説明は省略する。 In addition, in all the figures for explaining the examples,
Components having the same function are given the same reference numerals, and repeated explanations thereof will be omitted.
実施例
第１図は、本発明の実施例のMRI装置全体
の概略回路構成の説明図、
第２図は、第１図のMRI装置の要部の概略構
成を説明するための要部断面図、
本実施例のMRI装置は、第１図及び第２図
に示すように、核磁気共鳴（NMR）現象を利用
して被検体１の断層画像を得るものであり、静磁
場発生磁石２、中央処理装置（CPU）３、シー
ケンサ４、送信系５、磁場勾配発生系（傾斜磁場
電源６と傾斜磁場コイル７）、受信系８及び信号
処理系９とを備えている。Embodiment FIG. 1 is an explanatory diagram of a schematic circuit configuration of the entire MRI apparatus according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part for explaining a schematic configuration of the essential parts of the MRI apparatus of FIG. 1. As shown in FIGS. 1 and 2, the MRI apparatus of this embodiment obtains a tomographic image of a subject 1 using nuclear magnetic resonance (NMR) phenomenon, and includes a static magnetic field generating magnet 2, It includes a central processing unit (CPU) 3, a sequencer 4, a transmission system 5, a magnetic field gradient generation system (gradient magnetic field power supply 6 and gradient magnetic field coil 7), a reception system 8, and a signal processing system 9.
前記静磁場発生磁石２は、被検体１の周りにそ
の体軸方向（水平方向）、又は体軸と直交する方
向（垂直方向）に強く均一な静磁場を発生させる
もので、前記被検体１の周りにある広がりをもつ
た空間に氷久磁石方式、常電導方式あるいは超電
導方式の磁場発生手段が配置されている。本実施
例では静磁場方向を図中矢印の向きとした。 The static magnetic field generating magnet 2 generates a strong and uniform static magnetic field around the subject 1 in the body axis direction (horizontal direction) or in a direction perpendicular to the body axis (vertical direction). A magnetic field generating means of a Hikyu magnet type, a normal conduction type, or a superconducting type is arranged in a spacious space around the . In this embodiment, the direction of the static magnetic field is indicated by the arrow in the figure.
前記シーケンサ４は、CPU３の制御で動作し、
被検体１の断層画像のデータ収集に必要な種々の
命令を送信系５、磁場勾配発生系（傾斜磁場電源
６と傾斜磁場コイル７）及び受信系８に送るもの
である。 The sequencer 4 operates under the control of the CPU 3,
Various commands necessary for data collection of tomographic images of the subject 1 are sent to the transmission system 5, the magnetic field gradient generation system (gradient magnetic field power source 6 and gradient magnetic field coil 7), and the receiving system 8.
前記送信系５は、高周波発振器１０、変調器１
１、高周波増幅器１２及び送信側の高周波コイル
２０ａから成り、前記高周波発振器１０から出力
された高周波パルスをシーケンサ４の命令に従つ
て変調器１１で振幅変調し、この振幅変調された
高周波パルスを高周波増幅した後に、被検体１に
近接して配置された高周波コイル２０ａに供給す
ることにより、電磁波が前記被検体１に照射され
るようになつている。 The transmission system 5 includes a high frequency oscillator 10 and a modulator 1
1. Consists of a high frequency amplifier 12 and a high frequency coil 20a on the transmitting side, the high frequency pulse output from the high frequency oscillator 10 is amplitude modulated by a modulator 11 according to the command of the sequencer 4, and the amplitude modulated high frequency pulse is converted into a high frequency pulse. After being amplified, the electromagnetic waves are supplied to a high-frequency coil 20a placed close to the subject 1, so that the subject 1 is irradiated with electromagnetic waves.
前記磁場勾配発生系は、Ｘ，Ｙ，Ｚの三軸方向
に巻かれた傾斜磁場コイル７及びそれぞれのコイ
ルを駆動する傾斜磁場電源６から成り、前記シー
ケンサ４からの命令に従つてそれぞれのコイルの
傾斜磁場電源６を駆動することにより、Ｘ，Ｙ，
Ｚの三軸方向の傾斜磁場GX，GY，GZを被検体
１に印加するようになつている。この傾斜磁場の
加え方により、被検体１に対するスライス面を設
定することができる。 The magnetic field gradient generation system consists of gradient magnetic field coils 7 wound in the three axes directions of X, Y, and Z, and a gradient magnetic field power supply 6 that drives each coil. By driving the gradient magnetic field power supply 6 of
Gradient magnetic fields GX, GY, and GZ in the three axial directions of Z are applied to the subject 1. Depending on how this gradient magnetic field is applied, a slice plane for the subject 1 can be set.
前記受信系８は、受信側のソレノイド形の高周
波コイル２０ｂ及び増幅器１３から成り、前記送
信側高周波コイル２０ａから照射された電磁波に
よる被検体１の応答の電磁波（NMR信号）は、
被検体１に近接して配置された高周波コイル２０
ｂで検出され、増幅器１３及び直交位相検波器１
４を介してＡ／Ｄ変換器１５に入力してデイジタ
ル量に変換され、さらに、シーケンサ４からの命
令によるタイミングで直交位相検波器１４によ
り、サンプリングされた二系列の収集データとさ
れ、その信号が信号処理系９に送られるようにな
つている。 The receiving system 8 consists of a solenoid-type high frequency coil 20b on the receiving side and an amplifier 13, and the electromagnetic waves (NMR signals) of the response of the subject 1 due to the electromagnetic waves irradiated from the transmitting side high frequency coil 20a are as follows:
High frequency coil 20 placed close to the subject 1
b, the amplifier 13 and the quadrature phase detector 1
4 to the A/D converter 15 and converted into a digital quantity.Furthermore, the signal is converted into two series of sampled collected data by the quadrature phase detector 14 at the timing according to the command from the sequencer 4. is sent to the signal processing system 9.
この信号処理系９は、CPU３及びデイスプレ
イ２１から成り、前記CPU３でフーリエ変換、
補正系数計算像構成等の処理を行い、任意断面の
信号強度分布あるいは複数の信号に適当な演算を
行つて得られた分布を画像化してデイスプレイ２
１に表示するようになつている。 This signal processing system 9 consists of a CPU 3 and a display 21, and the CPU 3 performs Fourier transform,
After performing processing such as correction system calculation image configuration, the signal intensity distribution of an arbitrary cross section or the distribution obtained by performing appropriate calculations on multiple signals is converted into an image and displayed on the display 2.
1 is displayed.
ここで、図中、静磁場方向に周囲環境磁場に変
動があると、核磁気共鳴の共鳴周波数がそれによ
つて変動し、画像のボケ、ゴーストが発生する。 Here, in the figure, if there is a change in the ambient magnetic field in the direction of the static magnetic field, the resonance frequency of nuclear magnetic resonance changes accordingly, causing image blurring and ghosting.
本実施例における環境磁場変動補正部は、磁
場センサ１６、増幅器１７、補正磁場コイル電源
１８及び補正磁場コイル１９から成る。 The environmental magnetic field fluctuation correction section in this embodiment includes a magnetic field sensor 16, an amplifier 17, a correction magnetic field coil power supply 18, and a correction magnetic field coil 19.
磁場センサ１６は、例えば、第３図に示すよう
に、検査室１００の環境磁場変動を生じ易い側の
角部に配置される。第３図において、１０１は不
要な磁場を発生する電車線路、１０２はガント
リ、１０３はテーブルである。磁場センサ１６
は、静磁場方向の環境磁場変動を検出し、この検
出された出力は、増幅器１７により増幅される。 For example, as shown in FIG. 3, the magnetic field sensor 16 is placed at a corner of the examination room 100 on the side where environmental magnetic field fluctuations are likely to occur. In FIG. 3, reference numeral 101 is a train track that generates unnecessary magnetic fields, 102 is a gantry, and 103 is a table. Magnetic field sensor 16
detects environmental magnetic field fluctuations in the direction of the static magnetic field, and the detected output is amplified by the amplifier 17.
補正磁場コイル電源１８は、第１図及び第２図
に示すように、傾斜磁場コイル７の近くに配置さ
れる。 The correction magnetic field coil power supply 18 is arranged near the gradient magnetic field coil 7, as shown in FIGS. 1 and 2.
補正磁場コイル１９は、第２図に示すように、
磁気回路５０の磁極５０１に傾斜磁場コイル７と
近接して巻かれている。 The correction magnetic field coil 19, as shown in FIG.
It is wound around the magnetic pole 501 of the magnetic circuit 50 in close proximity to the gradient magnetic field coil 7 .
前記増幅器１７の出力波形（環境磁場変動波
形）の電流を補正磁場コイル１９に流し、環境磁
場変動を打ち消す方向の磁場を発生させる。 A current having the output waveform (environmental magnetic field fluctuation waveform) of the amplifier 17 is passed through the correction magnetic field coil 19 to generate a magnetic field in the direction of canceling the environmental magnetic field fluctuation.
以上の説明からわかるように、本実施例によれ
ば、環境磁場変動を検出する磁場センサ１６が、
MRI装置の近くに配置され、この磁場センサ１
６に発生する出力波形を増幅し、この出力波形に
応じた電流を補正磁場コイル１９に流せば、必要
な空間内において環境磁場変動を打ち消すための
磁場を発生させることができる。それによつて環
境磁場が変動しても必要な空間内の磁場を安定に
保つことができる。 As can be seen from the above description, according to this embodiment, the magnetic field sensor 16 that detects environmental magnetic field fluctuations is
This magnetic field sensor 1 is placed near the MRI machine.
By amplifying the output waveform generated at 6 and passing a current corresponding to this output waveform through the correction magnetic field coil 19, it is possible to generate a magnetic field for canceling environmental magnetic field fluctuations within the required space. This makes it possible to maintain a stable magnetic field within the required space even if the environmental magnetic field fluctuates.
実施例
第４図は、本発明のMRI装置の実施例の環
境磁場変動補正部の概略構成を説明するための要
部説明図、
第５図は、第４図の環境磁場変動補正部の動作
を説明するための波形図である。Embodiment FIG. 4 is a main part explanatory diagram for explaining the schematic configuration of the environmental magnetic field fluctuation correction section of the embodiment of the MRI apparatus of the present invention, and FIG. 5 shows the operation of the environmental magnetic field fluctuation correction section in FIG. 4. FIG. 2 is a waveform diagram for explaining.
実施例の環境磁場変動補正部は、磁場センサ
１６、増幅器１７Ａ，１７Ｂ、補正磁場コイル電
源１８Ａ，１８Ｂ及び補正磁場コイル１９A1，
１９A2，１９B1，１９B2から成る。 The environmental magnetic field fluctuation correction unit of the embodiment includes a magnetic field sensor 16, amplifiers 17A, 17B, correction magnetic field coil power supplies 18A, 18B, and correction magnetic field coil 19A 1 ,
It consists of 19A 2 , 19B 1 and 19B 2 .
次に、環境磁場補正部の動作を第５図を用いて
説明する。 Next, the operation of the environmental magnetic field correction section will be explained using FIG. 5.
第５図は、被検体１を含む空間内の環境磁場の
変化を説明するための説明図である。 FIG. 5 is an explanatory diagram for explaining changes in the environmental magnetic field in the space containing the subject 1. FIG.
第５図において、イは補正しない場合の被検体
１を含む空間内の変動磁場の強度波形、ロは補正
磁場コイル１９A1，１９A2のみを使用した場合
の被検体１を含む空間内の変動磁場の強度波形、
ハは補正磁場コイル１９A1，１９A2を使用し、
さらに補正磁場コイル１９B1，１９B2を使用す
る場合の被検体１を含む空間内の変動磁場の強度
波形である。 In Fig. 5, A is the intensity waveform of the fluctuating magnetic field in the space containing the subject 1 without correction, and B is the variation in the space containing the subject 1 when only the correction magnetic field coils 19A 1 and 19A 2 are used. magnetic field strength waveform,
C uses correction magnetic field coils 19A 1 and 19A 2 ,
Furthermore, it is the intensity waveform of the varying magnetic field in the space including the subject 1 when using the correction magnetic field coils 19B 1 and 19B 2 .
また、実線は被検体１を含む空間内の変動磁場
の強度波形（補正なしの場合）、点線は補正磁場
コイル１９A1，１９A2，１９B1，１９B2に発生
される補正磁場である。 Further, the solid line is the intensity waveform of the varying magnetic field in the space including the subject 1 (in the case of no correction), and the dotted line is the correction magnetic field generated in the correction magnetic field coils 19A 1 , 19A 2 , 19B 1 , 19B 2 .
前記磁場センサ１６は、静磁場方向の環境磁場
変動を検出し、この検出された出力は、増幅器１
７Ａにより増幅される。この増幅器１７Ａの出力
波形（環境磁場変動波形）の電流を補正磁場コイ
ル１９A1及び１９A2に流し、環境磁場変動を打
ち消す方向の磁場を発生させると、環境磁場変動
を打ち消す方向の磁場より、第５図のロのような
磁場波形となる。さらに、前記増幅器１７Ｂの出
力波形の電流を補正磁場コイル１９B1，１９B2
に流し、環境磁場変動を打ち消す方向の磁場を発
生させると、第５図のハに示すように、被検体１
を含む空間内の変動磁場がほとんどなくなる。 The magnetic field sensor 16 detects environmental magnetic field fluctuations in the direction of the static magnetic field, and the detected output is sent to the amplifier 1.
7A. When the current of the output waveform (environmental magnetic field fluctuation waveform) of this amplifier 17A is passed through the correction magnetic field coils 19A 1 and 19A 2 to generate a magnetic field in the direction of canceling the environmental magnetic field fluctuation, the magnetic field in the direction of canceling the environmental magnetic field fluctuation becomes more The magnetic field waveform will be as shown in Figure 5 (b). Furthermore, the current of the output waveform of the amplifier 17B is corrected by magnetic field coils 19B 1 and 19B 2 .
When a magnetic field is generated in the direction of canceling the environmental magnetic field fluctuation, as shown in Figure 5 C, the object 1
The fluctuating magnetic field in the space containing the space is almost eliminated.
以上、本発明を実施例にもとずき具体的に説明
したが、本発明は、前記実施例に限定されるもの
ではなく、その要旨を逸脱しない範囲において
種々変更可能であることは言うまでもない。 Although the present invention has been specifically explained above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. .
例えば、前記実施例では、補正磁場コイルの
上下一対の組みを２つ使用したが、３つ以上でも
よい。 For example, in the embodiment described above, two pairs of upper and lower correction magnetic field coils are used, but three or more may be used.
以上、説明したように、本発明によれば、補正
磁場を発生させることにより、環境磁場変動を打
ち消すことができるので、環境磁場変動の影響を
低減することができる。
As described above, according to the present invention, environmental magnetic field fluctuations can be canceled by generating a correction magnetic field, so that the influence of environmental magnetic field fluctuations can be reduced.
第１図は、本発明の実施例のMRI装置全体
の概略回路構成の説明図、第２図は、第１図の
MRI装置の要部の概略構成を説明するための要
部断面図、第３図は、第１図に示す磁場センサの
配置位置を示すレイアウト図、第４図は、本発明
のMRI装置の実施例の環境磁場変動補正部の
概略構成を説明するための要部説明図、第５図
は、第４図の環境磁場変動補正部の動作を説明す
るための波形図である。
図中、１……被検体、２……静磁場発生磁石、
３……中央処理装置（CPU）、４……シーケン
サ、５……送信系、６……傾斜磁場電源、７……
傾斜磁場コイル、８……受信系、９……信号処理
系、１０……高周波発振器、１１……変調器、１
２……高周波増幅器、１３……増幅器、１４……
直交位相検波器、１５……Ａ／Ｄ変換器、１６…
…磁場センサ、１７，１７Ａ，１７Ｂ……増幅
器、１８，１８Ａ，１８Ｂ……補正磁場コイル電
源、１９，１９A1，１９A2，１９B1，１９B2…
…補正磁場コイル、２０ａ，２０ｂ……高周波コ
イル、２１……デイスプレイである。
FIG. 1 is an explanatory diagram of the general circuit configuration of the entire MRI apparatus according to the embodiment of the present invention, and FIG. 2 is the same as that of FIG.
FIG. 3 is a cross-sectional view of the main parts for explaining the schematic configuration of the main parts of the MRI apparatus, FIG. 3 is a layout diagram showing the arrangement position of the magnetic field sensor shown in FIG. 1, and FIG. 4 is a diagram showing the implementation of the MRI apparatus of the present invention. FIG. 5 is a main part explanatory diagram for explaining the schematic configuration of the example environmental magnetic field fluctuation correction section, and FIG. 5 is a waveform diagram for explaining the operation of the environmental magnetic field fluctuation correction section in FIG. 4. In the figure, 1...subject, 2...static magnetic field generating magnet,
3... Central processing unit (CPU), 4... Sequencer, 5... Transmission system, 6... Gradient magnetic field power supply, 7...
Gradient magnetic field coil, 8... Receiving system, 9... Signal processing system, 10... High frequency oscillator, 11... Modulator, 1
2...High frequency amplifier, 13...Amplifier, 14...
Quadrature phase detector, 15... A/D converter, 16...
...Magnetic field sensor, 17, 17A, 17B...Amplifier, 18, 18A, 18B...Correction magnetic field coil power supply, 19, 19A 1 , 19A 2 , 19B 1 , 19B 2 ...
...Correction magnetic field coil, 20a, 20b...high frequency coil, 21...display.
Claims (1)
均一な静磁場を形成する静磁場発生磁石と、前記
静磁場内の複数方向に傾斜磁場を発生する傾斜磁
場発生手段と、前記被検体の特定断面における磁
場の強さで決定される周波数をもつ電磁波を照射
し前記特定断面内の組織を構成する原子核に共鳴
現象を起こさせる送信高周波コイルと、該電磁波
照射による核磁気共鳴信号を検出する受信高周波
コイルとを備える磁気共鳴イメージング装置にお
いて、被検体の配置される前記空間内に前記静磁
場発生磁石とは別個に磁場補正コイルを設けると
ともに、装置の外部に磁場センサを配置し、か
つ、この磁場センサの磁場変動にともなう出力に
より該変動分の磁場を相殺させる磁場を前記磁場
補正コイルに発生させる制御手段を備えたことを
特徴とする磁気共鳴イメージング装置。1. A static magnetic field generating magnet that forms a substantially uniform static magnetic field in a predetermined spatial region in which the subject is placed, a gradient magnetic field generating means that generates gradient magnetic fields in multiple directions within the static magnetic field, and A transmitting high-frequency coil that irradiates electromagnetic waves with a frequency determined by the strength of the magnetic field in a specific cross section to cause a resonance phenomenon in the atomic nuclei constituting the tissue in the specific cross section, and detects a nuclear magnetic resonance signal due to the electromagnetic wave irradiation. A magnetic resonance imaging apparatus including a receiving high-frequency coil, a magnetic field correction coil being provided in the space where the subject is placed separately from the static magnetic field generating magnet, and a magnetic field sensor being placed outside the apparatus, and A magnetic resonance imaging apparatus comprising: a control means for causing the magnetic field correction coil to generate a magnetic field that cancels out the magnetic field variation by an output caused by the magnetic field variation of the magnetic field sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63195390A JPH0245035A (en) | 1988-08-05 | 1988-08-05 | Magnetic resonance imaging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63195390A JPH0245035A (en) | 1988-08-05 | 1988-08-05 | Magnetic resonance imaging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0245035A JPH0245035A (en) | 1990-02-15 |
| JPH0376134B2 true JPH0376134B2 (en) | 1991-12-04 |
Family
ID=16340357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63195390A Granted JPH0245035A (en) | 1988-08-05 | 1988-08-05 | Magnetic resonance imaging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0245035A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5245286A (en) * | 1991-04-18 | 1993-09-14 | The Regents Of The University Of California | Apparatus and method for stabilizing the background magnetic field during mri |
| JP3339885B2 (en) * | 1992-08-26 | 2002-10-28 | 株式会社日立メディコ | Magnetic resonance imaging equipment |
| IT1294226B1 (it) * | 1997-08-01 | 1999-03-24 | Itel Telecomunicazioni S R L | Sistema attivo per la compensazione di campi magnetici di disturbo particolarmente adatti per l'uso su tomografi per risonanza magnetica |
| US10656227B2 (en) * | 2015-05-12 | 2020-05-19 | Koninklijke Philips N.V. | Magnetic resonance examination system with field probes |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6267433A (en) * | 1985-09-20 | 1987-03-27 | Yokogawa Electric Corp | Nmr imaging apparatus |
| JPS6363441A (en) * | 1986-09-03 | 1988-03-19 | 横河電機株式会社 | Nuclear magnetic resonance image pickup apparatus |
| JPS63301507A (en) * | 1986-08-20 | 1988-12-08 | スペクトロシュピン・ア−ゲ− | Apparatus for compensating field interference varied with time in magnetic field |
-
1988
- 1988-08-05 JP JP63195390A patent/JPH0245035A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6267433A (en) * | 1985-09-20 | 1987-03-27 | Yokogawa Electric Corp | Nmr imaging apparatus |
| JPS63301507A (en) * | 1986-08-20 | 1988-12-08 | スペクトロシュピン・ア−ゲ− | Apparatus for compensating field interference varied with time in magnetic field |
| JPS6363441A (en) * | 1986-09-03 | 1988-03-19 | 横河電機株式会社 | Nuclear magnetic resonance image pickup apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0245035A (en) | 1990-02-15 |
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