JP2001314390A - Catheter for magnetic resonance imaging apparatus - Google Patents
Catheter for magnetic resonance imaging apparatusInfo
- Publication number
- JP2001314390A JP2001314390A JP2000137176A JP2000137176A JP2001314390A JP 2001314390 A JP2001314390 A JP 2001314390A JP 2000137176 A JP2000137176 A JP 2000137176A JP 2000137176 A JP2000137176 A JP 2000137176A JP 2001314390 A JP2001314390 A JP 2001314390A
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- JP
- Japan
- Prior art keywords
- magnetic resonance
- catheter
- imaging apparatus
- balun
- resonance imaging
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、静磁場中の被検体
に傾斜磁場パルスと高周波パルスを印加して、それによ
り発生する磁気共鳴信号から磁気共鳴画像や磁気共鳴ス
ペクトル等の有意な情報を取得する磁気共鳴映像装置の
撮像領域内で用いられる磁気共鳴映像装置用カテーテル
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention applies a gradient magnetic field pulse and a high-frequency pulse to a subject in a static magnetic field, and generates significant information such as a magnetic resonance image and a magnetic resonance spectrum from a magnetic resonance signal generated thereby. The present invention relates to a catheter for a magnetic resonance imaging apparatus used in an imaging region of the magnetic resonance imaging apparatus to be acquired.
【０００２】[0002]
【従来の技術】磁気共鳴映像装置（ＭＲＩ）は、よく知
られているように、固有の磁気モーメントを持つ核の集
団が一様な静磁場中に置かれたときに、特定の周波数で
回転する高周波磁場のエネルギーを共鳴的に吸収する現
象を利用して、物質の化学的及び物理的な微視的情報を
映像化したり、あるいは化学シフトスペクトルを観測す
る装置である。2. Description of the Related Art As is well known, a magnetic resonance imaging apparatus (MRI) rotates at a specific frequency when a group of nuclei having a unique magnetic moment is placed in a uniform static magnetic field. It is a device that visualizes chemical and physical microscopic information of a substance or observes a chemical shift spectrum using the phenomenon of resonantly absorbing the energy of a high-frequency magnetic field.
【０００３】近年、生体内部から高感度に磁気共鳴信号
を取得したり、術中の患部の撮像などのために、被検体
内の撮像対象付近まで挿入できるカテーテル型の小型高
周波コイルの研究がなされている。しかし、被検体の広
い領域を撮像するように又は被検体の広い領域に高周波
磁場を印加するために、被検体の外部に配置された大型
の高周波コイルから高周波磁場が印加された時、被検体
内に挿入された小型高周波コイル及びその接続ケーブル
の外部被覆導電体に高周波電流が流れ、高周波コイル及
び接続ケーブル付近で被検体内に温度上昇をきたすとい
う問題があった。また、鉗子用のカテーテルを挿入した
状態で撮像する場合でも、カテーテル自体が金属等の導
電体でできている場合は、やはり高周波電流が流れ、そ
の周辺組織の温度が上昇するという問題があった。In recent years, research has been conducted on a small catheter-type high-frequency coil that can be inserted into the vicinity of an imaging target in a subject to acquire a magnetic resonance signal with high sensitivity from the inside of a living body or to image an affected part during surgery. I have. However, when a high-frequency magnetic field is applied from a large high-frequency coil disposed outside the subject so as to image a wide area of the subject or to apply a high-frequency magnetic field to the wide area of the subject, There is a problem that a high-frequency current flows through the small-sized high-frequency coil inserted into the inside and the externally-covered conductor of the connection cable thereof, and the temperature rises in the subject near the high-frequency coil and the connection cable. Further, even when imaging is performed with a catheter for forceps inserted, if the catheter itself is made of a conductive material such as metal, a high-frequency current also flows and the temperature of the surrounding tissue increases. .
【０００４】ところで、従来から、アンテナ技術の分野
では、同軸ケーブルの外皮導電体に高周波電流が流れる
のを防ぐための遮断手段として、例えばバズーカ型バラ
ンが知られている。Meanwhile, in the field of antenna technology, a bazooka balun, for example, is known as a blocking means for preventing a high-frequency current from flowing through the outer conductor of a coaxial cable.
【０００５】このバズーカ型バランを、高周波コイルの
接続ケーブルに採用することが、文献「Magnetic reson
ance in Medicine, 37, 112-118, 1997」等に掲載され
ている。バズーカ型バランを採用する目的は、通常受信
時における平衡・不平衡変換器としてである。従って、
高周波コイルの接続ケーブルに、バランが単一で装着さ
れているに過ぎない。つまり、カテーテル型の高周波コ
イルに１つのバランを装着しているが、これは、平衡・
不平衡変換を目的として装着されたものであるので、複
数装着する必要はないものである。１つでは高周波電流
の抑圧、そして送信時の温度上昇を防ぐためにはそれほ
ど効果的ではなく、外部高周波コイルから高周波磁場を
送信した時にバランの外側に高周波電流が流れることに
なり、温度上昇を防ぐことはできない。The use of this bazooka-type balun as a connection cable for a high-frequency coil is disclosed in "Magnetic reson".
ance in Medicine, 37, 112-118, 1997 ". The purpose of using the bazooka type balun is as a balanced / unbalanced converter during normal reception. Therefore,
The balun is simply attached to the connection cable of the high frequency coil. In other words, one balun is attached to the catheter-type high-frequency coil.
Since it is mounted for the purpose of unbalanced conversion, it is not necessary to mount a plurality of them. One is not very effective in suppressing high-frequency current and preventing temperature rise during transmission. When a high-frequency magnetic field is transmitted from an external high-frequency coil, high-frequency current flows outside the balun, preventing temperature rise. It is not possible.
【０００６】周知の通り、高周波電流を抑圧し、温度上
昇を防ぐためには、複数のバランをカテーテルの導電性
外被に直列に接続することが望ましい。図５に代表的な
バランの構造を示す。図５（ａ）は縦断面を示し、
（ｂ）は横断面を示している。カテーテルの導電管２３
の外側に、円筒形のバラン２０を配し、一端を導電管２
３に接続する。使われる磁気共鳴周波数の波長をλとし
たときに、バラン２０をλ／４の長さにすることによ
り、伝送線路の理論から非短絡方向から見たインピーダ
ンスが高くなり、導電管２３に流れようとする高周波電
流を効果的に抑圧できる。実質的な波長λは、バラン２
０の充填物質２１の比誘電率εｒ に依存して変化す
る。以下の式に示す。[0006] As is well known, it is desirable to connect a plurality of baluns in series with the conductive jacket of the catheter in order to suppress high frequency current and prevent temperature rise. FIG. 5 shows a typical balun structure. FIG. 5A shows a longitudinal section,
(B) has shown the cross section. Conductive tube 23 of catheter
A balun 20 having a cylindrical shape is disposed outside the tube, and one end of the balun 20 is connected to the conductive tube 2.
Connect to 3. When the wavelength of the magnetic resonance frequency to be used is λ, by setting the balun 20 to have a length of λ / 4, the impedance as viewed from the non-short circuit direction increases from the theory of the transmission line, so that the balun 20 flows to the conductive tube 23. Can be effectively suppressed. The substantial wavelength λ is balun 2
It changes depending on the relative permittivity ε r of the filling material 21 of 0. It is shown in the following equation.
【０００７】λ＝λ０ ／εｒ １／２ ここでλ０ は真空中における波長である。充填物質と
してテトラフルオロエチレンを使う場合、その比誘電率
はほぼ２であり、現在臨床で使用される磁気共鳴装置で
もっとも周波数が高いのは、６４ＭＨｚ（磁場強度１．
５Ｔ）であるから、λ／４の長さは、８０ｃｍ程度にな
る。この場合、実際送信用高周波磁場に晒される最大で
約１．５ｍ程度の範囲においては、せいぜい２個程度の
バラン２０を設けるのが物理的に見て限界であり、温度
上昇を有意に防ぐことができない。Λ = λ 0 / ε r 1/2 where λ 0 is the wavelength in vacuum. When tetrafluoroethylene is used as the filling material, its relative dielectric constant is approximately 2, and the highest frequency among magnetic resonance apparatuses currently used in clinical practice is 64 MHz (magnetic field strength 1.
5T), the length of λ / 4 is about 80 cm. In this case, it is physically limited to provide at most about two baluns 20 in a range of about 1.5 m at maximum which is actually exposed to the transmitting high-frequency magnetic field. Can not.
【０００８】このように、生体内部から高感度に磁気共
鳴信号を取得したり、術中の患部の撮像などのために、
被検体内の撮像対象付近まで挿入できる小型の高周波コ
イルにおいて、被検体の広い領域に高周波磁場を印加す
るために被検体の外部に配置された大型の高周波コイル
から高周波磁場が印加された場合、被検体内に挿入され
た小型の高周波コイル及び接続ケーブルの外部被覆導電
体に高周波電流が流れ、高周波コイル及び接続ケーブル
付近で被検体内に温度上昇をきたすという問題があっ
た。あるいは、鉗子用カテーテルを挿入した状態で撮像
する場合でも、カテーテル管が導電体でできている場合
は、やはりこの導電管に高周波電流が流れ、その周辺組
織の温度が上昇するという問題があり、有効な解決手段
がなかった。As described above, in order to obtain a magnetic resonance signal with high sensitivity from the inside of a living body and to image an affected part during an operation, etc.
When a high-frequency magnetic field is applied from a large high-frequency coil arranged outside the subject in order to apply a high-frequency magnetic field to a wide area of the subject, in a small high-frequency coil that can be inserted to the vicinity of the imaging target in the subject, There has been a problem that a high-frequency current flows through the small-sized high-frequency coil inserted into the subject and the externally coated conductor of the connection cable, and the temperature rises in the subject near the high-frequency coil and the connection cable. Alternatively, even when imaging is performed with the forceps catheter inserted, if the catheter tube is made of a conductor, there is still a problem that high-frequency current flows through this conductive tube and the temperature of the surrounding tissue rises. There was no effective solution.
【０００９】[0009]
【発明が解決しようとする課題】本発明の目的は、磁気
共鳴映像装置の撮像領域内で使われる磁気共鳴映像装置
用カテーテルにおいて、効果的に高周波電流を抑圧し、
そしてそれに起因していた温度上昇を防止することにあ
る。SUMMARY OF THE INVENTION An object of the present invention is to provide a catheter for a magnetic resonance imaging apparatus used in an imaging region of a magnetic resonance imaging apparatus, which effectively suppresses a high-frequency current.
Another object of the present invention is to prevent a temperature rise caused thereby.
【００１０】[0010]
【課題を解決するための手段】本発明は、該円管状の導
電体被覆を持ち、前記導電体被覆には所定の磁気共鳴周
波数の高周波電流を遮蔽する遮断手段が３個以上設けら
れることを特徴とする磁気共鳴映像装置用カテーテルで
ある。According to the present invention, there is provided the present invention is characterized in that the conductor coating has a tubular shape, and the conductor coating is provided with three or more interrupting means for shielding a high-frequency current having a predetermined magnetic resonance frequency. It is a catheter for a magnetic resonance imaging apparatus, which is a feature.
【００１１】[0011]
【発明の実施の形態】以下、図面を参照して本発明によ
る磁気共鳴映像装置用カテーテルを好ましい実施形態に
より説明する。 （第１実施形態）図１は本発明の第１実施形態に係る磁
気共鳴映像装置用カテーテルの構造を示している。な
お、磁気共鳴映像装置用カテーテルとは、図１（ａ）に
示す鉗子２を誘導するタイプのカテーテルや図１（ｂ）
に示すカテーテル型の小型高周波コイルが典型的である
が、磁気共鳴映像装置の撮像領域内で使われる可能性の
ある導電性を持つ管を採用しているすべての種類のカテ
ーテルが本発明の適用範囲に属するものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the catheter for a magnetic resonance imaging apparatus according to the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows the structure of a catheter for a magnetic resonance imaging apparatus according to a first embodiment of the present invention. Note that the catheter for a magnetic resonance imaging apparatus is a catheter of the type for guiding the forceps 2 shown in FIG.
Although a catheter-type small high-frequency coil shown in Fig. 1 is typical, all kinds of catheters employing a conductive tube which may be used in an imaging region of a magnetic resonance imaging apparatus are applicable to the present invention. It belongs to the range.
【００１２】図１（ａ）の場合、導管１それ自体が金属
等の導電性材料で作られており、また図１（ｂ）の場
合、同軸ケーブルであり、中心導線１２と対をなす外側
導電管１１がそれに相当する。これら中心導線１２と外
側導電管１１との間にはインダクタンス１３と共振用コ
ンデンサ１４とインピーダンスマッチング用コンデンサ
１５とが接続されている。また図１（ｃ）に示すよう
に、外部導電管１とバラン３とのスペースには、テトラ
フルオロエチレン等の誘電物質４が充填されている。In the case of FIG. 1A, the conduit 1 itself is made of a conductive material such as a metal, and in the case of FIG. 1B, it is a coaxial cable. The conductive tube 11 corresponds to this. An inductance 13, a resonance capacitor 14, and an impedance matching capacitor 15 are connected between the center conductor 12 and the outer conductive tube 11. Further, as shown in FIG. 1C, the space between the external conductive tube 1 and the balun 3 is filled with a dielectric material 4 such as tetrafluoroethylene.
【００１３】これら導管１や外側導電管１１に流れる高
周波電流を抑圧するための遮蔽手段として、円筒形のバ
ズーカ型バラン３が、導管１や外側導電管１１が撮影領
域内に入る最大で約１．５ｍ程度の範囲に、複数、具体
的には従来では不可能な３個以上、装着されている。従
来では、バラン長は、λ／４、つまり８０ｃｍ程度であ
ったので、当該範囲に、２個が限界であったが、本発明
では３個以上達成している。これを実現するために、バ
ラン３の短縮化が図られている。このバラン３の短縮化
について以下に説明する。As a shielding means for suppressing the high-frequency current flowing through the conduit 1 and the outer conductive tube 11, a cylindrical bazooka type balun 3 is provided. A plurality of, specifically, three or more, which are impossible in the related art, are mounted in a range of about 0.5 m. Conventionally, the balun length is λ / 4, that is, about 80 cm, so that two pieces are the limit in the range, but three or more pieces are achieved in the present invention. In order to achieve this, the balun 3 is shortened. The shortening of the balun 3 will be described below.
【００１４】図２（ａ）は、本実施形態に係るバラン３
の縦断面図であり、その横断面が図２（ｂ）に示されて
いる。このバラン３の開放端と導管１の表面との間に少
なくとも１つの容量性素子（コンデンサ）９が設けられ
る。つまり、当該バラン３の開放端と導管１の表面との
間がコンデンサ９で短絡されている。FIG. 2A shows a balun 3 according to this embodiment.
FIG. 2B is a vertical cross-sectional view of which is shown in FIG. At least one capacitive element (capacitor) 9 is provided between the open end of the balun 3 and the surface of the conduit 1. That is, the capacitor 9 short-circuits the open end of the balun 3 and the surface of the conduit 1.
【００１５】このコンデンサ９の容量Ｃを、充填物質４
の比誘電率εｒ から計算される波長λの１／４よりも
短い目的とする長さｌにする場合、損失を無視すれば、
以下の式に従って設定すればよい。The capacity C of this capacitor 9 is
When the target length l is shorter than ４ of the wavelength λ calculated from the relative permittivity ε r of
What is necessary is just to set according to the following formula.
【００１６】 Ｃ＝１／（２πｆ・Ｚ０ ・ｔａｎ（２πｌ／λ）） なお、Ｚ０ はバラン３の特性インピーダンス、ｆは磁
気共鳴周波数（Ｈｚ）を表している。[0016] C = 1 / (2πf · Z 0 · tan (2πl / λ)) Incidentally, Z 0 is the characteristic impedance of the balun 3, f represents the magnetic resonance frequency (Hz).
【００１７】このようにコンデンサ９の容量Ｃを調整す
ることで、例えば、コンデンサ９の容量Ｃを、５０ＰＦ
程度にすれば、バラン３の長さを約１０ｃｍに調整する
ことができ、これにより３個以上のバラン３を、導管１
や外側導電管１１が撮影領域内に入る最大で約１．５ｍ
程度の範囲内に十分余裕を持って装着することができ
る。従って、高周波電流を効果的に抑圧し、そしてそれ
に起因していた温度上昇を防止することができる。By adjusting the capacitance C of the capacitor 9 as described above, for example, the capacitance C of the capacitor 9 is reduced by 50 PF.
In this case, the length of the balun 3 can be adjusted to about 10 cm, so that three or more baluns 3 can be connected to the conduit 1.
And the outer conductive tube 11 is about 1.5 m at the maximum within the shooting area.
It can be mounted with a sufficient margin within the range of the degree. Therefore, the high-frequency current can be effectively suppressed, and the temperature rise caused by the high-frequency current can be prevented.
【００１８】（第２実施形態）図３に第２実施形態に係
るカテーテルのバランを示していて、図３（ａ）にはそ
のバランの縦断面図、図３（ｂ）には横断面図をそれぞ
れ示している。従来技術のところで述べたように、実質
的な波長λは、以下の式に示すように、バラン３の充填
物質の比誘電率εｒ に依存して変化する。。(Second Embodiment) FIG. 3 shows a balun of a catheter according to a second embodiment. FIG. 3 (a) is a longitudinal sectional view of the balun, and FIG. 3 (b) is a transverse sectional view. Are respectively shown. As described in the prior art, the substantial wavelength λ changes depending on the relative permittivity ε r of the balun 3 filling material as shown in the following equation. .
【００１９】λ＝λ０ ／εｒ １／２ ここでλ０ は真空中における波長である。Λ = λ 0 / ε r 1/2 where λ 0 is a wavelength in a vacuum.
【００２０】つまり、充填物質に比誘電率の高い物質を
用いれば、バラン３の長さを十分短縮できる。例えば、
水は比誘電率がほぼ８０であり、同軸ケーブルの代表的
な充填物質であるテトラフルオロエチレンの４０倍ほど
大きい。よって、バラン３の長さを、１０ｃｍや１３ｃ
ｍ程度に短縮できる。しかし、水ではバラン３と外側導
電管１との隙間に固定しにくいので、含水性高分子を充
填しても良い。また水を吸収して膨らむ素材を充填物質
として挿入しておいても良い。その場合、生体に挿入す
る際に、あらかじめ水中に入れて十分水を含ませた後、
挿入することで、所望の波長短縮効果が得られる。ま
た、最終的に生体に挿入するので、生体中の水分が間隙
に進入するように構成しても良い。That is, if a material having a high relative dielectric constant is used as the filling material, the length of the balun 3 can be sufficiently reduced. For example,
Water has a relative dielectric constant of approximately 80 and is about 40 times larger than tetrafluoroethylene, a typical filling material for coaxial cables. Therefore, the length of the balun 3 is set to 10 cm or 13 c
m. However, since it is difficult to fix water to the gap between the balun 3 and the outer conductive tube 1, it may be filled with a water-containing polymer. A material that absorbs water and swells may be inserted as a filling material. In that case, when inserting it into the living body, put it in water in advance and allow it to contain enough water,
By inserting, a desired wavelength shortening effect can be obtained. In addition, since it is finally inserted into the living body, it may be configured such that moisture in the living body enters the gap.
【００２１】図３は、バラン３を、その隙間に生体中の
水分が良好に浸入するように工夫したその構造を示して
いる。このバラン３の短絡端には、複数の孔１０が円周
方向に沿って離散的に開けられており、ここから水がバ
ラン３と外側導電管１との隙間に容易に浸入するように
なっている。FIG. 3 shows a structure in which the balun 3 is devised so that moisture in a living body can well enter the gap. At the short-circuited end of the balun 3, a plurality of holes 10 are discretely formed along the circumferential direction, from which water can easily enter the gap between the balun 3 and the outer conductive tube 1. ing.
【００２２】さらに水分の浸入生を高めるために、図４
に示すような編線等の網状導電線１１でバラン３の導電
体筒を構成してもよい。To further increase the infiltration of water, FIG.
The conductor tube of the balun 3 may be constituted by a mesh-like conductive wire 11 such as a knitted wire as shown in FIG.
【００２３】このようにバラン３と外側導電管１との隙
間に充填する材料を水又は水を主成分とする物質等の比
誘電率の高い物質、つまり所望とするバラン３の長さに
応じた比較的高い比誘電率の物質を選定すれば、バラン
３の長さを短縮でき、これにより３個以上のバラン３
を、導管１や外側導電管１１が撮影領域内に入る最大で
約１．５ｍ程度の範囲内に十分余裕を持って装着するこ
とができる。従って、高周波電流を効果的に抑圧し、そ
してそれに起因していた温度上昇を防止することができ
る。As described above, the material filling the gap between the balun 3 and the outer conductive tube 1 is made of a substance having a high relative dielectric constant such as water or a substance containing water as a main component, ie, a desired length of the balun 3. If a material having a relatively high relative dielectric constant is selected, the length of the balun 3 can be shortened, and thereby three or more baluns 3 can be formed.
Can be mounted with a sufficient margin within a range of about 1.5 m at the maximum where the conduit 1 and the outer conductive tube 11 enter the imaging region. Therefore, the high-frequency current can be effectively suppressed, and the temperature rise caused by the high-frequency current can be prevented.
【００２４】本発明は上述した実施形態に限定されず、
種々変形して実施可能である。例えば、上述のカテーテ
ルにおいて、外部が導電体でできているため、絶縁皮膜
が必要な場合もある。また、生体に挿入した際は、無用
な免疫的拒絶現象、血小板の付着による血栓などができ
ないよう生体適合性の処理を表面に施してもよい。The present invention is not limited to the embodiment described above,
Various modifications are possible. For example, in the above-mentioned catheter, the outside is made of a conductive material, so that an insulating film may be necessary. When inserted into a living body, a biocompatible treatment may be applied to the surface so that useless immune rejection and thrombosis due to the attachment of platelets cannot be caused.
【００２５】[0025]
【発明の効果】本発明によれば、複数のバランを設ける
ことができるので、の長さを短縮して、磁気共鳴映像装
置用カテーテルにおいて、外部に設けられた送信用高周
波コイルにより高周波磁場が印加されても、近傍で温度
上昇が生じないように構成された磁気共鳴映像装置用カ
テーテルを提供することが可能となる。According to the present invention, since a plurality of baluns can be provided, the length of the balun can be reduced, and a high-frequency magnetic field can be reduced by a transmitting high-frequency coil provided outside in a catheter for a magnetic resonance imaging apparatus. It is possible to provide a magnetic resonance imaging apparatus catheter configured so that the temperature does not increase in the vicinity even when the voltage is applied.
【図１】（ａ）は本発明の第１実施形態に係る鉗子用カ
テーテルの縦断面図、（ｂ）は高周波コイル用カテーテ
ルの縦断面図、（ｃ）はカテーテルの横断面図。1A is a longitudinal sectional view of a forceps catheter according to a first embodiment of the present invention, FIG. 1B is a longitudinal sectional view of a high-frequency coil catheter, and FIG. 1C is a transverse sectional view of the catheter.
【図２】（ａ）は図１のバランの縦断面図、（ｂ）は
（ａ）のバランの横断面図。2A is a longitudinal sectional view of the balun of FIG. 1, and FIG. 2B is a transverse sectional view of the balun of FIG.
【図３】第２実施形態に係るカテーテルの構造図であっ
て、（ａ）はバランの縦断面図、（ｂ）はバランの横断
面図。3A and 3B are structural views of a catheter according to a second embodiment, in which FIG. 3A is a longitudinal sectional view of a balun, and FIG. 3B is a transverse sectional view of the balun.
【図４】第２実施形態において、バランの他の構造を示
す斜視図。FIG. 4 is a perspective view showing another structure of the balun in the second embodiment.
【図５】従来のバランの構造を示す図。FIG. 5 is a view showing a structure of a conventional balun.
１…外部導電体、 ２…鉗子、 ３…バラン、 ４…充填物質、 ９…コンデンサ、 １０…孔、 １１…網上導電線、 １２…高周波コイル、 １３…インダクタンス、 １４…共振用コンデンサ、 １５…インピーダンスマッチング用コンデンサ。 DESCRIPTION OF SYMBOLS 1 ... External conductor, 2 ... Forceps, 3 ... Balun, 4 ... Filling substance, 9 ... Capacitor, 10 ... Hole, 11 ... Conductive wire on wire, 12 ... High frequency coil, 13 ... Inductance, 14 ... Resonant capacitor, 15 ... A capacitor for impedance matching.
Claims (11)
体被覆には所定の磁気共鳴周波数の高周波電流を遮蔽す
る遮断手段が３個以上設けられることを特徴とする磁気
共鳴映像装置用カテーテル。1. A magnetic resonance imaging apparatus for a magnetic resonance imaging apparatus, comprising: a tubular conductor coating, wherein the conductor coating is provided with three or more cutoff means for blocking a high-frequency current having a predetermined magnetic resonance frequency. catheter.
磁気共鳴信号を少なくとも受信する高周波コイルに接続
する同軸ケーブルを含むカテーテルであることを特徴と
する請求項１記載の磁気共鳴映像装置用カテーテル。2. The catheter for a magnetic resonance imaging apparatus according to claim 1, wherein the catheter for a magnetic resonance apparatus includes a coaxial cable connected to a high-frequency coil for receiving at least the magnetic resonance signal.
ることを特徴とする請求項１記載の磁気共鳴映像装置用
カテーテル。3. The catheter for a magnetic resonance imaging apparatus according to claim 1, wherein said blocking means is a bazooka type balun.
する手段を具備することを特徴とする請求項３記載の磁
気共鳴映像装置用カテーテル。4. The catheter for a magnetic resonance imaging apparatus according to claim 3, wherein said bazooka type balun includes means for shortening a substantial length.
る手段は、前記バズーカ型バランの開口端に接続された
容量性素子であることを特徴とする請求項４記載の磁気
共鳴映像装置用カテーテル。5. The catheter for a magnetic resonance imaging apparatus according to claim 4, wherein the means for shortening the substantial length of the bazooka balun is a capacitive element connected to an open end of the bazooka balun. .
る手段は、前記バズーカ型バランと前記導電体被覆との
間隙に充填された、テトラフルオロエチレンよりも比誘
電率の高い物質であることを特徴とする請求項４記載の
磁気共鳴装置用カテーテル。6. The means for shortening the substantial length of the bazooka balun may be a substance filled in a gap between the bazooka balun and the conductor coating and having a higher dielectric constant than tetrafluoroethylene. The catheter for a magnetic resonance apparatus according to claim 4, characterized in that:
主成分とする物質であることを特徴とする請求項６記載
の磁気共鳴映像装置用カテーテル。7. The catheter for a magnetic resonance imaging apparatus according to claim 6, wherein the substance having a high relative dielectric constant is water or a substance containing water as a main component.
ルが生体内に挿入された際、生体中の水分が進入する構
造を備えていることを特徴とする請求項７記載の磁気共
鳴装置用カテーテル。8. The catheter for a magnetic resonance apparatus according to claim 7, wherein the bazooka balun has a structure into which water in the living body enters when the catheter is inserted into the living body.
高周波パルスを印加して、発生する磁気共鳴信号から磁
気共鳴画像及び磁気共鳴スペクトルを取得する磁気共鳴
映像装置に用いられる磁気共鳴映像装置用カテーテルに
おいて、前記磁気共鳴装置用カテーテルは、磁気共鳴信
号を少なくとも受信する高周波コイルとこれに接続する
同軸ケーブルからなり、該同軸ケーブルの外部被覆に所
定の磁気共鳴周波数の高周波電流が流れないようにする
遮断手段を直列に３個以上装着したことを特徴とする磁
気共鳴映像装置用カテーテル。9. A magnetic resonance image used in a magnetic resonance imaging apparatus for applying a gradient magnetic field pulse and a high frequency pulse to a subject in a static magnetic field and acquiring a magnetic resonance image and a magnetic resonance spectrum from a generated magnetic resonance signal. In the device catheter, the magnetic resonance device catheter includes a high-frequency coil for receiving at least a magnetic resonance signal and a coaxial cable connected thereto, and a high-frequency current of a predetermined magnetic resonance frequency does not flow through the outer coating of the coaxial cable. 3. A catheter for a magnetic resonance imaging apparatus, comprising three or more blocking means arranged in series.
段を具備したバズーカ型バランであることを特徴とする
請求項９記載の磁気共鳴映像装置用カテーテル。10. The catheter for a magnetic resonance imaging apparatus according to claim 9, wherein said blocking means is a bazooka type balun provided with means for shortening a substantial length.
て、所定の磁気共鳴周波数の高周波電流が流れないよう
にする複数の遮断手段を含む外部被覆部分は、被検体と
の電気的絶縁手段または生体適合手段の少なくとも一方
で処理されていること特徴とする請求項１または１１記
載の磁気共鳴装置用カテーテル。11. In the catheter for a magnetic resonance apparatus, an outer covering portion including a plurality of blocking means for preventing a high-frequency current having a predetermined magnetic resonance frequency from flowing is electrically insulated from a subject or biocompatible means. The catheter for a magnetic resonance apparatus according to claim 1 or 11, wherein the catheter is treated with at least one of the following.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000137176A JP2001314390A (en) | 2000-05-10 | 2000-05-10 | Catheter for magnetic resonance imaging apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000137176A JP2001314390A (en) | 2000-05-10 | 2000-05-10 | Catheter for magnetic resonance imaging apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2001314390A true JP2001314390A (en) | 2001-11-13 |
Family
ID=18644990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000137176A Pending JP2001314390A (en) | 2000-05-10 | 2000-05-10 | Catheter for magnetic resonance imaging apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2001314390A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7056466B2 (en) | 2002-03-28 | 2006-06-06 | Scimed Life Systems, Inc. | Method of manufacture medical devices employing microwave energy |
| US7163655B2 (en) | 2002-03-28 | 2007-01-16 | Scimed Life Systems, Inc. | Method and apparatus for extruding polymers employing microwave energy |
| US7531122B2 (en) | 2002-03-28 | 2009-05-12 | Boston Scientific Scimed, Inc. | Polymer welding using ferromagnetic particles |
| JP2013141504A (en) * | 2012-01-10 | 2013-07-22 | Toshiba Corp | Rf coil unit and magnetic resonance imaging apparatus |
| US8862203B2 (en) | 2003-03-27 | 2014-10-14 | Boston Scientific Scimed Inc. | Medical device with temperature modulator for use in magnetic resonance imaging |
-
2000
- 2000-05-10 JP JP2000137176A patent/JP2001314390A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7056466B2 (en) | 2002-03-28 | 2006-06-06 | Scimed Life Systems, Inc. | Method of manufacture medical devices employing microwave energy |
| US7163655B2 (en) | 2002-03-28 | 2007-01-16 | Scimed Life Systems, Inc. | Method and apparatus for extruding polymers employing microwave energy |
| US7458798B2 (en) | 2002-03-28 | 2008-12-02 | Boston Scientific Scimed, Inc. | Apparatus for extruding polymers employing microwave energy |
| US7531122B2 (en) | 2002-03-28 | 2009-05-12 | Boston Scientific Scimed, Inc. | Polymer welding using ferromagnetic particles |
| US8862203B2 (en) | 2003-03-27 | 2014-10-14 | Boston Scientific Scimed Inc. | Medical device with temperature modulator for use in magnetic resonance imaging |
| JP2013141504A (en) * | 2012-01-10 | 2013-07-22 | Toshiba Corp | Rf coil unit and magnetic resonance imaging apparatus |
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