JP2008000626A - Magnetic resonance diagnostic apparatus - Google Patents

Magnetic resonance diagnostic apparatus Download PDF

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JP2008000626A
JP2008000626A JP2007245149A JP2007245149A JP2008000626A JP 2008000626 A JP2008000626 A JP 2008000626A JP 2007245149 A JP2007245149 A JP 2007245149A JP 2007245149 A JP2007245149 A JP 2007245149A JP 2008000626 A JP2008000626 A JP 2008000626A
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pulse
magnetic field
dimensional
diagnostic apparatus
magnetic resonance
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Shinichi Kishiyu
慎一 喜種
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Toshiba Corp
Canon Medical Systems Corp
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Toshiba Medical Systems Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic resonance diagnostic apparatus capable of executing three-dimensional MR angiography, while sufficiently maintaining a fat control effect, without much degrading MR signals from the bloodstream. <P>SOLUTION: A magnetic resonance diagnostic apparatus comprises gradient magnetic field power sources 7 to 9 which can apply a gradient magnetic field on a static magnetic field, RF transducing sections 5 and 6 which can transmit RF pulses to a subject in the static magnetic field and receive MR signals from the subject, and a sequencer 10 which controls the gradient magnetic field power sources and the RF transducing sections. The sequencer is designed to control the gradient magnetic power sources and the RF transducing sections according to a prescribed pulse sequence. The pulse sequence includes a prepulse having an additional effect and an imaging sequence for collecting MR signals from the three-dimensional region of the subject according to the 3DFT law. The prepulse is applied so as to bring an additional effect only on part of the region including areas in and around the origin of a three-dimensional k space under the 3DFT law. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、脂肪抑制をかけて頭部等の血流を効果的に撮影する３次元ＭＲアンギオグラフィー（血流撮影法）の可能な磁気共鳴診断装置に関する。   The present invention relates to a magnetic resonance diagnostic apparatus capable of three-dimensional MR angiography (blood flow imaging method) that effectively captures blood flow of a head or the like by applying fat suppression.

図１０にフィールドエコー法を基本とした従来の３次元ＭＲアンギオグラフィーのパルスシーケンスを示している。このＭＲアンギオグラフィーの原理は、撮影ボリューム内の脳実質や臓器等の静止物体はその縦磁化があまり回復していないうちに次々と励起されるので信号レベルは徐々に低くなっていくが、血液（水）は常にフレッシュな状態でボリュームに流入してくるので、静止物体ほどは信号低下は見られない。このため血流が静止物体に比べて相対的に強調されたような画像（血流画像）が得られることになる。   FIG. 10 shows a pulse sequence of a conventional three-dimensional MR angiography based on the field echo method. The principle of MR angiography is that stationary objects such as brain parenchyma and organs in the imaging volume are excited one after another while their longitudinal magnetization has not recovered much, so the signal level gradually decreases. Since (water) always flows into the volume in a fresh state, the signal drop is not as high as that of a stationary object. For this reason, an image (blood flow image) in which blood flow is relatively emphasized as compared with a stationary object is obtained.

このようなＭＲアンギオグラフィーでは、画質向上のために様々な工夫がなされている。代表的には、イメージングシーケンスを繰り返すごとにその直前に脂肪抑制パルスをプリパルスとして印加して、脂肪抑制を図っている（図１１参照）。   In such MR angiography, various contrivances have been made to improve image quality. Typically, each time the imaging sequence is repeated, a fat suppression pulse is applied as a pre-pulse immediately before the imaging sequence to suppress fat suppression (see FIG. 11).

また、近年では、SINCパルスとオフセットパルスで構成されて、水のプロトンの共鳴周波数から少しずれた周波数のＭＴＣ(Magnetization Transfer Contrast) パルスと呼ばれるＲＦパルスを、イメージングシーケンスの直前にプリパルスとして印加し、これにより起こる水のプロトンと、脳実質を主に構成する高分子のプロトンとの間のＭＴＣ効果によって、脳実質からの信号を水（血液）からの信号よりも相対的に弱くして血流抽出能を高めるといった技術も開発されている。   In recent years, an RF pulse called an MTC (Magnetization Transfer Contrast) pulse composed of a SINC pulse and an offset pulse and slightly shifted from the resonance frequency of water protons is applied as a pre-pulse immediately before the imaging sequence, Due to the MTC effect between the protons of water and the protons of macromolecules mainly constituting the brain parenchyma, the signal from the brain parenchyma is made relatively weaker than the signal from the water (blood), and the blood flow Techniques have been developed to increase extraction ability.

さらに、この技術を応用して、特許文献１に開示されているように、ＭＴＣパルスをスライス選択傾斜磁場と共に印加して（ＳＯＲＳパルス）、このＳＯＲＳパルスで心臓から撮影領域２２より遠い領域２１を励起することにより、動脈流を強調するような技術も開発されている（図１２）。   Further, by applying this technique, as disclosed in Patent Document 1, an MTC pulse is applied together with a slice selective gradient magnetic field (SORS pulse), and a region 21 farther from the imaging region 22 from the heart is detected by this SORS pulse. A technique for enhancing arterial flow by excitation has also been developed (FIG. 12).

このように様々に工夫されている３次元ＭＲアンギオグラフィーであるが、上述したように脂肪抑制パルスをイメージングシーケンスを繰り返してＭＲ信号を収集する毎に印加していたので、３次元ｋ空間の全域にわたって、当該脂肪抑制パルスのサイドローブ（広帯域化）が磁場不均一性を伴って影響し、脂肪と一緒に水のプロトンも抑制されてしまい、血流画像が完全に落ちてしまうという事態が起こる可能性があった。   Although the three-dimensional MR angiography is devised in various ways as described above, since the fat suppression pulse is applied every time the MR sequence is acquired by repeating the imaging sequence as described above, the entire region of the three-dimensional k-space is obtained. Over time, the side lobe (broadband) of the fat suppression pulse is affected with magnetic field inhomogeneity, and the proton of water is suppressed together with fat, resulting in a situation where the blood flow image is completely dropped. There was a possibility.

かかる脂肪抑制パルスのサイドローブの影響を少なくするには、sinc波形の脂肪抑制パルスを例えば±π長から±４・π長に延長して、狭帯域化することが効果的である。しかし、脂肪抑制パルスを長くすればその分、撮影時間を延長せざるを得なくなり、臨床上不都合が生じる。さらに、ＭＲアンギオグラフィーでは、上述したように縦磁化の不十分な回復を利用して静止物体の信号低下を図っているので、繰り返し時間ＴＲが長くなるような脂肪抑制パルスの延長はとても許容できない。
特開平６−３１９７１５号公報 In order to reduce the influence of the side lobe of the fat suppression pulse, it is effective to extend the fat suppression pulse having a sinc waveform from ± π length to ± 4 · π length, for example, to narrow the band. However, if the fat suppression pulse is lengthened, the imaging time must be extended accordingly, which causes clinical inconvenience. Furthermore, in MR angiography, as described above, insufficient recovery of longitudinal magnetization is used to reduce the signal of a stationary object. Therefore, it is very unacceptable to extend a fat suppression pulse that increases the repetition time TR. .
JP-A-6-319715

本発明の目的は、血流からのＭＲ信号があまり低下することなく、しかも脂肪制御効果も十分維持できるような３次元ＭＲアンギオグラフィーの可能な磁気共鳴診断装置を提供することである。   An object of the present invention is to provide a magnetic resonance diagnostic apparatus capable of three-dimensional MR angiography, in which MR signals from the bloodstream do not decrease so much and the fat control effect can be sufficiently maintained.

本発明は、静磁場に重ねて傾斜磁場を印加可能な傾斜磁場印加手段と、前記静磁場中の被検体にＲＦパルスを送信すると共に前記被検体からのＭＲ信号を受信可能なＲＦ送受信手段と、前記傾斜磁場印加手段と前記ＲＦ送受信手段とを制御する制御手段とを備えた磁気共鳴診断装置において、前記制御手段は所定のパルスシーケンスに従って前記傾斜磁場印加手段と前記ＲＦ送受信手段とを制御するようになっており、前記パルスシーケンスは、付加的効果を与えるプリパルスと、前記被検体の３次元領域から３ＤＦＴ法に従ってＭＲ信号を収集するイメージングシーケンスとを含み、前記プリパルスは、前記３ＤＦＴ法の３次元ｋ空間の原点付近を含む一部の領域にのみ付加的効果が及ぶように印加されるものであることを特徴とする磁気共鳴診断装置である。   The present invention includes a gradient magnetic field applying unit capable of applying a gradient magnetic field superimposed on a static magnetic field, and an RF transmitting / receiving unit capable of transmitting an RF pulse to the subject in the static magnetic field and receiving an MR signal from the subject. In the magnetic resonance diagnostic apparatus comprising a control means for controlling the gradient magnetic field applying means and the RF transmitting / receiving means, the control means controls the gradient magnetic field applying means and the RF transmitting / receiving means according to a predetermined pulse sequence. The pulse sequence includes a pre-pulse that gives an additional effect, and an imaging sequence that collects MR signals from a three-dimensional region of the subject according to a 3DFT method, and the prepulse includes 3D of the 3DFT method. Magnetism characterized in that it is applied so as to exert an additional effect only on a part of the region including the vicinity of the origin of the dimension k space. It is a ringing diagnostic equipment.

本発明によれば、血流からのＭＲ信号があまり低下することなく、しかも脂肪制御効果も十分維持できるような３次元ＭＲアンギオグラフィーの可能な磁気共鳴診断装置を提供することができる。   According to the present invention, it is possible to provide a magnetic resonance diagnostic apparatus capable of three-dimensional MR angiography in which MR signals from the bloodstream do not decrease so much and the fat control effect can be sufficiently maintained.

以下、図面を参照して、本発明による磁気共鳴診断装置の一実施形態を説明する。図１に本実施形態に係る磁気共鳴診断装置の構成を示す。コイルガントリ２０には、静磁場磁石１、傾斜磁場コイル２、ＲＦコイル３が設けられている。傾斜磁場コイル２は直交するＸＹＺの３軸にそれぞれ対応する傾斜磁場電源７，８，９から電流の供給を受けて、静磁場磁石１及び静磁場制御装置４とにより形成された静磁場にＸＹＺ各軸の傾斜磁場を重畳するために設けられている。これら３軸の傾斜磁場を個別に又は適当に組み合わせて、撮影ボリュームの幅や位置を決めたり、ＭＲ信号にスライスエンコードをかけたりするための傾斜磁場ＧS （ＧSE）、ＭＲ信号に位相エンコードをかけるための傾斜磁場ＧPE、ＭＲ信号に周波数エンコードをかけるための傾斜磁場ＧROを形成するようになっている。 Hereinafter, an embodiment of a magnetic resonance diagnostic apparatus according to the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a magnetic resonance diagnostic apparatus according to this embodiment. The coil gantry 20 is provided with a static magnetic field magnet 1, a gradient magnetic field coil 2, and an RF coil 3. The gradient coil 2 receives current from gradient magnetic field power supplies 7, 8, and 9 corresponding to three orthogonal XYZ axes, and applies XYZ to the static magnetic field formed by the static magnetic field magnet 1 and the static magnetic field control device 4. It is provided to superimpose the gradient magnetic field of each axis. These three-axis gradient magnetic fields are individually or appropriately combined to determine the width and position of the imaging volume, and to apply slice encoding to the MR signal, gradient magnetic field G S (G SE ), and phase encode the MR signal. A gradient magnetic field G PE for applying a frequency gradient and a gradient magnetic field G RO for applying frequency encoding to an MR signal are formed.

また、ＲＦコイル３は、送信器５と共に被検体ＰにＲＦパルスを印加し、また受信器６と共に被検体からＭＲ信号を受信するために設けられている。ここでは、ＲＦコイル３は、送受信兼用としているが、送信用と受信用とを別々に設けてもよい。   The RF coil 3 is provided for applying an RF pulse to the subject P together with the transmitter 5 and for receiving an MR signal from the subject together with the receiver 6. Here, the RF coil 3 is used for both transmission and reception, but transmission and reception may be provided separately.

シーケンサ１０は、後述する所定のパルスシーケンスに従って、送信器５、受信器６、傾斜磁場電源７，８，９を制御する。コンピュータシステム１１は、装置全体のホストコンピュータとしての機能の他に、受信器６からのＭＲ信号から３ＤＦＴ（３次元フーリエ変換）法に従ってＭＲ画像、ここでは血流画像を再構成する演算機能を有している。表示部１２には、コンピュータシステム１１で再構成された血流画像が表示される。   The sequencer 10 controls the transmitter 5, the receiver 6, and the gradient magnetic field power supplies 7, 8, 9 according to a predetermined pulse sequence described later. The computer system 11 has an arithmetic function for reconstructing an MR image, here, a blood flow image from the MR signal from the receiver 6 according to the 3DFT (three-dimensional Fourier transform) method, in addition to the function as a host computer of the entire apparatus. is doing. A blood flow image reconstructed by the computer system 11 is displayed on the display unit 12.

図２には、本実施形態により選択的に脂肪抑制がかけられる３次元ｋ空間上での低周波領域を示し、図３（ａ）には図２の低周波領域のＭＲ信号を収集するためのパルスシーケンスを示し、図３（ｂ）には図２の低周波領域以外の高周波領域のＭＲ信号を収集するためのパルスシーケンスを示している。これらの図からわかるように、イメージングシーケンスとしては、short ＴＲのフィールドエコー法と、３ＤＦＴ（３次元フーリエ変換）法に従って組まれている。なお、イメージングシーケンスは、short ＴＲのフィールドエコー法以外のエコー等の発生シーケンスと３ＤＦＴ法との組み合わせであってもよい。   FIG. 2 shows a low-frequency region on a three-dimensional k-space that is selectively subjected to fat suppression according to the present embodiment, and FIG. 3A shows an MR signal for collecting the low-frequency region of FIG. FIG. 3B shows a pulse sequence for collecting MR signals in a high frequency region other than the low frequency region in FIG. As can be seen from these figures, the imaging sequence is assembled according to the short TR field echo method and the 3DFT (three-dimensional Fourier transform) method. The imaging sequence may be a combination of a 3DFT method and a generation sequence such as an echo other than the short TR field echo method.

本実施形態では、このイメージングシーケンスで、３次元ｋ空間上で、スライスエンコード方向に関して画像コントラストに支配的な低周波領域のＭＲ信号を収集するときには、その直前に、プリパルスとしてＳＯＲＳパルスと脂肪抑制パルスを印加するが、高周波領域のＭＲ信号を収集するときには、ＳＯＲＳパルスと脂肪抑制パルスを印加しない。   In this embodiment, when acquiring MR signals in a low-frequency region that is dominant in image contrast with respect to the slice encoding direction on the three-dimensional k-space in this imaging sequence, a SORS pulse and a fat saturation pulse are used as prepulses immediately before that. However, when MR signals in the high frequency region are collected, the SORS pulse and the fat suppression pulse are not applied.

このように高周波領域ではＳＯＲＳパルスと脂肪抑制パルスを印加しないようにしているので、磁場不均一性を伴って起こる脂肪抑制パルスのサイドローブの影響は、従来のように、３次元ｋ空間の全域でなく、画像コントラストに支配的な低周波領域だけに及ぶことになり、血流信号が極端に落ちることなく、しかも、脂肪抑制効果やＳＯＲＳパルスによる脳実質抑制効果といった付加的効果も奏することができる。   As described above, since the SORS pulse and the fat saturation pulse are not applied in the high frequency region, the influence of the side lobe of the fat saturation pulse caused by the magnetic field inhomogeneity is, as in the conventional case, the entire area of the three-dimensional k-space. Not only the low-frequency region that is dominant in the image contrast, but the blood flow signal does not drop drastically, and there are additional effects such as a fat suppression effect and a brain parenchyma suppression effect by SORS pulse. it can.

また、高周波領域ではＳＯＲＳパルスと脂肪抑制パルスを印加しないので、図４に示すように、イメージングシーケンスにより３次元ｋ空間上の高周波領域のＭＲ信号を収集するときの繰り返し時間ＴＲHIGHは、低周波領域のＭＲ信号を収集するときの繰り返し時間ＴＲLOW よりも短縮して、撮影時間を短くすることができる。 Further, since the SORS pulse and the fat suppression pulse are not applied in the high frequency region, as shown in FIG. 4, the repetition time TR HIGH when collecting MR signals in the high frequency region on the three-dimensional k space by the imaging sequence is low frequency. The imaging time can be shortened by shortening the repetition time TR LOW when collecting MR signals in the region.

なお、イメージングシーケンス内の励起パルスには、動脈において心臓から遠い血流も、心臓に近い血流と同等のコントラストで描画することを目的として開発されたＩＳＣＥパルスを採用してもよい。心臓から遠い動脈血流では、心臓に近い動脈血流よりも励起回数が多くなり、その励起回数に応じて静止物体と同様に信号レベルが小さくなってしまうことがある。   The excitation pulse in the imaging sequence may be an ISCE pulse developed for the purpose of rendering blood flow far from the heart in the artery with the same contrast as blood flow close to the heart. In the arterial blood flow far from the heart, the number of excitations is larger than in the arterial blood flow close to the heart, and the signal level may be reduced in the same way as a stationary object depending on the number of excitations.

一般的な励起パルスのパワープロファイルファイルは図５（ａ）に示すようにほぼ一定に成形されている。これに対して、ＩＳＣＥパルスでは、図５（ｂ）に示すように心臓から遠方になるほどパワーが高くなるようなパワープロファイルに成形している。このようなパワープロファイルによると、心臓から遠くなればなるほど、フリップ角を深くとることができるので、信号レベルの低下を補償することができる。   A power profile file of a general excitation pulse is formed almost constant as shown in FIG. On the other hand, in the ISCE pulse, as shown in FIG. 5B, the power profile is shaped such that the power increases as the distance from the heart increases. According to such a power profile, the farther away from the heart, the deeper the flip angle can be made, so that a decrease in signal level can be compensated.

このような本実施形態によれば、脂肪や脳実質部は十分抑制されているにも関わらず、血流は末梢まで十分描画される。   According to the present embodiment, blood flow is sufficiently drawn to the periphery even though fat and brain parenchyma are sufficiently suppressed.

なお上述では、３次元ｋ空間上のスライスエンコード方向に関して低周波領域のＭＲ信号を収集するときには、その直前に、ＳＯＲＳパルスと脂肪抑制パルスを印加するが、高周波領域のＭＲ信号を収集するときには、その直前にＳＯＲＳパルスと脂肪抑制パルスを印加しないと説明したが、図６（ａ）、図７に示すように３次元ｋ空間上の位相エンコード方向に関して低周波領域のＭＲ信号を収集するときに、その直前に、ＳＯＲＳパルスと脂肪抑制パルスを印加し、位相エンコード方向の高周波領域のＭＲ信号を収集するときには、その直前にＳＯＲＳパルスと脂肪抑制パルスを印加しないようにしてもよい。また、図６（ｂ）、図８に示すように３次元ｋ空間上のスライスエンコードと位相エンコードの両方向に関して柱状の低周波領域のＭＲ信号を収集するときにだけ、その直前に、ＳＯＲＳパルスと脂肪抑制パルスを印加し、それ以外の領域のＭＲ信号を収集するときには、その直前にＳＯＲＳパルスと脂肪抑制パルスを印加しないようにしてもよい。   In the above description, when collecting the MR signal in the low frequency region with respect to the slice encoding direction on the three-dimensional k space, the SORS pulse and the fat suppression pulse are applied immediately before, but when collecting the MR signal in the high frequency region, Although it has been described that the SORS pulse and the fat saturation pulse are not applied immediately before that, as shown in FIGS. 6A and 7, when acquiring MR signals in the low frequency region with respect to the phase encoding direction in the three-dimensional k space. When the SORS pulse and the fat saturation pulse are applied immediately before that, and the MR signal in the high frequency region in the phase encoding direction is collected, the SORS pulse and the fat saturation pulse may not be applied immediately before that. Also, as shown in FIG. 6B and FIG. 8, only when a columnar low-frequency MR signal is acquired in both the slice encoding and phase encoding directions on the three-dimensional k-space, the SORS pulse and When the fat suppression pulse is applied and MR signals in other regions are collected, the SORS pulse and the fat suppression pulse may not be applied immediately before that.

また、上述では、３次元ｋ空間上の低周波領域のＭＲ信号を収集するときには、そのイメージシーケンスを繰り返すごとに、ＳＯＲＳパルスと脂肪抑制パルスを印加すると説明したが、図９に示すように、ＳＯＲＳパルスと脂肪抑制パルスを１回印加した後に、その効果がある程度維持されている間に、イメージシーケンスを繰り返すようにしてもよい。   Further, in the above description, when collecting MR signals in a low-frequency region on the three-dimensional k space, each time the image sequence is repeated, the SORS pulse and the fat suppression pulse are applied. However, as shown in FIG. After applying the SORS pulse and the fat suppression pulse once, the image sequence may be repeated while the effect is maintained to some extent.

また、ＳＯＲＳパルスと脂肪抑制パルスの効果を発揮させる３次元ｋ空間上の低周波領域としては、３次元ｋ空間の原点付近を含む一部領域であればよく、ゼロエンコードを必ず含む必要はない、つまり３次元ｋ空間の原点のＭＲ信号を収集するときにはＳＯＲＳパルスと脂肪抑制パルスを印加しないようにしてもよい。   In addition, the low-frequency region on the three-dimensional k space that exhibits the effects of the SORS pulse and the fat saturation pulse may be a partial region including the vicinity of the origin of the three-dimensional k space, and does not necessarily include zero encoding. That is, when collecting MR signals at the origin of the three-dimensional k-space, the SORS pulse and the fat suppression pulse may not be applied.

また、３次元ｋ空間上でのＳＯＲＳパルスの効果を与える低周波領域と、脂肪抑制パルスの効果を与える低周波領域とは、同一である必要はなく（異なっていてもよく）、例えば３次元ｋ空間上の位相エンコード方向に関する低周波領域にＳＯＲＳパルスの効果を与え、３次元ｋ空間上のスライスエンコード方向に関する低周波領域に脂肪抑制パルスの効果を与えるようにしてもよい。   Further, the low-frequency region that gives the effect of the SORS pulse on the three-dimensional k-space and the low-frequency region that gives the effect of the fat suppression pulse are not necessarily the same (may be different), for example, three-dimensional The effect of the SORS pulse may be applied to the low frequency region related to the phase encoding direction in the k space, and the effect of the fat suppression pulse may be applied to the low frequency region related to the slice encoding direction in the three-dimensional k space.

また、３次元ｋ空間上の低周波領域のＭＲ信号を収集するときには、ＳＯＲＳパルスと脂肪抑制パルスを印加し、高周波領域ではＳＯＲＳパルスと脂肪抑制パルスを印加しないと説明したが、脂肪抑制パルスだけをこのように選択的に印加し、ＳＯＲＳパルスは常に印加して、３次元ｋ空間の全域にわたってそのＳＯＲＳ効果が及ぶようにしてもよい。   In addition, when collecting MR signals in the low-frequency region on the three-dimensional k space, the SORS pulse and the fat suppression pulse are applied, and the SORS pulse and the fat suppression pulse are not applied in the high-frequency region. May be selectively applied in this manner, and the SORS pulse may be applied constantly so that the SORS effect extends over the entire area of the three-dimensional k-space.

また、脂肪抑制パルスだけをこのように選択的に印加し、ＳＯＲＳパルスは常に印加しないようにして、３次元ｋ空間の全域にわたってそのＳＯＲＳ効果を発揮させないようにしてもよいし、逆に、ＳＯＲＳパルスだけをこのように選択的に印加し、脂肪抑制パルスは常に印加しないようにして、３次元ｋ空間の全域にわたってその脂肪抑制効果を発揮させないようにしてもよい。   Alternatively, only the fat suppression pulse may be selectively applied in this way, and the SORS pulse may not be applied at all times so that the SORS effect is not exerted over the entire area of the three-dimensional k-space. Only the pulse may be selectively applied in this way, and the fat suppression pulse may not always be applied so that the fat suppression effect is not exhibited over the entire area of the three-dimensional k-space.

なお、本発明は上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合わせにより、種々の発明を形成できる。例えば、実施形態に示される全構成要素から幾つかの構成要素を削除してもよい。さらに、異なる実施形態にわたる構成要素を適宜組み合わせてもよい。   Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

本実施形態の磁気共鳴診断装置のブロック図。The block diagram of the magnetic resonance diagnostic apparatus of this embodiment. 本実施形態により選択的に脂肪抑制がかけられる３次元ｋ空間上での低周波領域を示す図。The figure which shows the low frequency area | region on the three-dimensional k space where fat suppression is selectively applied by this embodiment. （ａ）は図２の低周波領域のＭＲ信号を収集するためのパルスシーケンスを示し、（ｂ）は図２の低周波領域以外の高周波領域のＭＲ信号を収集するためのパルスシーケンスを示す図。(A) shows a pulse sequence for collecting MR signals in the low frequency region of FIG. 2, and (b) shows a pulse sequence for collecting MR signals in a high frequency region other than the low frequency region of FIG. . （ａ）は図３（ａ）の繰り返し時間を示し、（ｂ）は図３（ｂ）の繰り返し時間を示す図。(A) shows the repetition time of FIG. 3 (a), (b) is a figure which shows the repetition time of FIG.3 (b). （ａ）は一般的な励起パルスのパワースペクトルを示し、（ｂ）はＩＳＣＥパルスのパワースペクトルを示す図。(A) shows the power spectrum of a general excitation pulse, (b) is a figure which shows the power spectrum of an ISCE pulse. （ａ）は脂肪抑制がかけられる３次元ｋ空間上での他の低周波領域を示す図、（ｂ）は脂肪抑制がかけられる３次元ｋ空間上でのさらに他の低周波領域を示す図。(A) is a diagram showing another low-frequency region on the three-dimensional k-space to which fat suppression is applied, and (b) is a diagram showing still another low-frequency region on the three-dimensional k-space to which fat suppression is applied. . （ａ）は図６（ａ）の低周波領域のＭＲ信号を収集するためのパルスシーケンスを示し、（ｂ）は図６（ａ）の低周波領域以外の高周波領域のＭＲ信号を収集するためのパルスシーケンスを示す図。(A) shows a pulse sequence for collecting MR signals in the low frequency region of FIG. 6 (a), and (b) is for collecting MR signals in a high frequency region other than the low frequency region of FIG. 6 (a). FIG. （ａ）は図６（ｂ）の低周波領域のＭＲ信号を収集するためのパルスシーケンスを示し、（ｂ）は図６（ｂ）の低周波領域以外の高周波領域のＭＲ信号を収集するためのパルスシーケンスを示す図。(A) shows a pulse sequence for collecting MR signals in the low frequency region of FIG. 6 (b), and (b) is for collecting MR signals in the high frequency region other than the low frequency region of FIG. 6 (b). FIG. 図４の変形を示す図。The figure which shows the deformation | transformation of FIG. 従来の３次元ＭＲアンギオグラフィーのためのパルスシーケンスを示す図。The figure which shows the pulse sequence for the conventional three-dimensional MR angiography. 従来の脂肪抑制領域を３次元ｋ空間上でみた図。The figure which looked at the conventional fat suppression area on three-dimensional k space. ＳＯＲＳパルスの説明図。Explanatory drawing of a SORS pulse.

符号の説明Explanation of symbols

１…静磁場磁石、２…傾斜磁場コイル、３…ＲＦコイル、４…静磁場制御装置、５…送信器、６…受信器、７…Ｘ軸傾斜磁場電源、８…Ｙ軸傾斜磁場電源、９…Ｚ軸傾斜磁場電源、１０…シーケンサ、１１…コンピュータシステム、１２…表示部、２０…コイルガントリ。 DESCRIPTION OF SYMBOLS 1 ... Static magnetic field magnet, 2 ... Gradient magnetic field coil, 3 ... RF coil, 4 ... Static magnetic field control apparatus, 5 ... Transmitter, 6 ... Receiver, 7 ... X-axis gradient magnetic field power supply, 8 ... Y-axis gradient magnetic field power supply, DESCRIPTION OF SYMBOLS 9 ... Z-axis gradient magnetic field power supply, 10 ... Sequencer, 11 ... Computer system, 12 ... Display part, 20 ... Coil gantry.

Claims (5)

静磁場に重ねて傾斜磁場を印加可能な傾斜磁場印加手段と、前記静磁場中の被検体にＲＦパルスを送信すると共に前記被検体からのＭＲ信号を受信可能なＲＦ送受信手段と、前記傾斜磁場印加手段と前記ＲＦ送受信手段とを制御する制御手段とを備えた磁気共鳴診断装置において、
前記制御手段は所定のパルスシーケンスに従って前記傾斜磁場印加手段と前記ＲＦ送受信手段とを制御するようになっており、
前記パルスシーケンスは、付加的効果を与えるプリパルスと、前記被検体の３次元領域から３ＤＦＴ法に従ってＭＲ信号を収集するイメージングシーケンスとを含み、
前記プリパルスは、前記３ＤＦＴ法の３次元ｋ空間の原点付近を含む一部の領域にのみ付加的効果が及ぶように印加されるものであることを特徴とする磁気共鳴診断装置。 A gradient magnetic field applying means capable of applying a gradient magnetic field superimposed on a static magnetic field; an RF transmitting / receiving means capable of transmitting an RF pulse to the subject in the static magnetic field and receiving an MR signal from the subject; and the gradient magnetic field In a magnetic resonance diagnostic apparatus comprising an applying means and a control means for controlling the RF transmitting / receiving means,
The control means controls the gradient magnetic field applying means and the RF transmitting / receiving means according to a predetermined pulse sequence,
The pulse sequence includes a pre-pulse that gives an additional effect, and an imaging sequence that collects MR signals from a three-dimensional region of the subject according to a 3DFT method,
The magnetic resonance diagnostic apparatus, wherein the pre-pulse is applied so as to exert an additional effect only on a partial region including the vicinity of the origin of the three-dimensional k-space of the 3DFT method. 前記プリパルスは、脂肪抑制パルスであることを特徴とする請求項１記載の磁気共鳴診断装置。 The magnetic resonance diagnostic apparatus according to claim 1, wherein the pre-pulse is a fat suppression pulse. 前記プリパルスは、ＭＴＣパルスと、それと実質的に同時に印加される傾斜磁場パルスとを含むＳＯＲＳパルスを有することを特徴とする請求項１記載の磁気共鳴診断装置。 2. The magnetic resonance diagnostic apparatus according to claim 1, wherein the pre-pulse includes a SORS pulse including an MTC pulse and a gradient magnetic field pulse applied substantially simultaneously with the MTC pulse. 前記パルスシーケンスは、前記イメージングシーケンスにより３次元ｋ空間上での低周波領域のＭＲ信号を収集するときには前記プリパルスを印加し、一方、前記イメージングシーケンスにより３次元ｋ空間上での高周波領域のＭＲ信号を収集するときには前記プリパルスを印加しないようになっていることを特徴とする請求項１記載の磁気共鳴診断装置。 The pulse sequence applies the pre-pulse when acquiring an MR signal in a low-frequency region on a three-dimensional k-space by the imaging sequence, while applying an MR signal in a high-frequency region on the three-dimensional k-space by the imaging sequence. The magnetic resonance diagnostic apparatus according to claim 1, wherein the pre-pulse is not applied when collecting data. 前記ＭＲ信号に基づいて前記被検体の血流画像を再構成する再構成手段をさらに備えたことを特徴とする請求項１乃至４のいずれか一項記載の磁気共鳴診断装置。 5. The magnetic resonance diagnostic apparatus according to claim 1, further comprising reconstruction means for reconstructing a blood flow image of the subject based on the MR signal.
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