JPH0293387A - Double tuning high frequency coil for magnetic resonance apparatus - Google Patents
Double tuning high frequency coil for magnetic resonance apparatusInfo
- Publication number
- JPH0293387A JPH0293387A JP63246436A JP24643688A JPH0293387A JP H0293387 A JPH0293387 A JP H0293387A JP 63246436 A JP63246436 A JP 63246436A JP 24643688 A JP24643688 A JP 24643688A JP H0293387 A JPH0293387 A JP H0293387A
- Authority
- JP
- Japan
- Prior art keywords
- conductors
- loop
- frequency
- coil
- parallel
- 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.)
- Granted
Links
- 239000004020 conductor Substances 0.000 claims abstract description 67
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000010168 coupling process Methods 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- 230000005540 biological transmission Effects 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- 230000035945 sensitivity Effects 0.000 description 9
- 239000000126 substance Substances 0.000 description 7
- 238000001514 detection method Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 239000000523 sample Substances 0.000 description 6
- 230000001939 inductive effect Effects 0.000 description 5
- 238000001228 spectrum Methods 0.000 description 5
- 230000003068 static effect Effects 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 241000555745 Sciuridae Species 0.000 description 2
- 238000013480 data collection Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000002595 magnetic resonance imaging Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Landscapes
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
この発明は磁気共鳴装置に用いられる高周波コイルに係
り、特に二重同調高周波コイルに関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high frequency coil used in a magnetic resonance apparatus, and particularly to a double-tuned high frequency coil.
（従来の技術）
磁気共鳴装置は固有の磁気モーメントを持つ原子核の集
団が−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、物質の化学的及び微視的な情報を映像化
したり、あるいは化学シフトスペクトルを観Δ−１する
装置である。このような磁気共鳴装置においては、被検
体内の関心領域に高周波磁場を照射したり、それによっ
て生じる磁気共鳴信号を検出するための高周波コイルが
不可欠である。(Prior art) A magnetic resonance apparatus studies the phenomenon in which a group of atomic nuclei with a unique magnetic moment, when placed in a static magnetic field, resonantly absorbs the energy of a high-frequency magnetic field that rotates at a specific frequency. It is a device that can be used to visualize chemical and microscopic information of substances, or to view chemical shift spectra. In such a magnetic resonance apparatus, a high-frequency coil is essential for irradiating a high-frequency magnetic field to a region of interest within a subject and detecting magnetic resonance signals generated thereby.
磁気共鳴映像２置によって１１Ｐ（リン）等の化学シフ
トスペクトルを得る場合、位置決めや磁場均一性の補正
のために、’Ｈ（プロトン）の画像を取得することが行
なわれる。このような場合、高周波磁場の発生及び磁気
共鳴信号の収集のための高周波コイルとしては、３１Ｐ
及び１Ｈのそれぞれの磁気共鳴周波数に同調するコイル
が必要である。このようなコイルを二重同調高周波コイ
ルという。従来の二重同調高周波コイルは、くら型コイ
ルによって実現されている。When obtaining a chemical shift spectrum of 11P (phosphorus) or the like using two-position magnetic resonance imaging, an image of 'H (proton) is acquired for positioning and correction of magnetic field uniformity. In such a case, a 31P high-frequency coil for generating a high-frequency magnetic field and collecting magnetic resonance signals is recommended.
Coils tuned to the respective magnetic resonance frequencies of 1H and 1H are required. Such a coil is called a double-tuned high-frequency coil. A conventional double-tuned high-frequency coil is realized by a saddle-shaped coil.
高周波コイルは高周波電力の効率や、画像及び化学シフ
トスペクトルデータのＳ／Ｎ向上のために、被検体にで
きるだけ密着して用いられることが望ましい。しかし、
高周波コイルとして従来用いられているくら型コイルで
は、均一な高周波磁場の発生が難しく、また磁気共鳴信
号検出感度の均一性が得られにくい。It is desirable that the high-frequency coil be used in close contact with the subject as much as possible in order to improve the efficiency of high-frequency power and the S/N of images and chemical shift spectrum data. but,
With a saddle-shaped coil conventionally used as a high-frequency coil, it is difficult to generate a uniform high-frequency magnetic field, and it is also difficult to obtain uniform magnetic resonance signal detection sensitivity.
一方、高周波磁場の均一性と磁気共鳴信号検出感度の均
一性が得られる高周波コイルとして、特開昭（ｉｏ−１
３２５４７号公報に記載されたような通称「鳥かご型コ
イル」が知られている。このコイルは全体としては円筒
状であり、導体部分のインダクタンスと、キャパシタン
ス素子とでコイルの一周に１波長の高周波が乗るような
遅延回路を構成しており、コイルの円周方向の角度をθ
としたとき、電流分布！ （θ）はｓｌｎθまたはｅＯ
３θに比例する。これによりコイルの内側において均一
な高周波磁場を発生でき、また磁気共鳴信号の検出感度
が均一化されるため、関心領域に密着させることができ
、従来のくら型コイルやソレノイドコイルよりも高いＳ
／Ｎが得られるというものである。この鳥かご型コイル
を二重同調高周波コイルとして構成できれば、２種の周
波数で高周波磁場の均一化と、磁気共鳴信号の検出感度
の均一化ができることになり、極めて有用と考えられる
が、このような二重同調高周波コイルは提案されていな
い。On the other hand, as a high-frequency coil that can obtain uniformity of high-frequency magnetic field and uniformity of magnetic resonance signal detection sensitivity,
A so-called "birdcage coil" as described in Japanese Patent No. 32547 is known. This coil has a cylindrical shape as a whole, and the inductance of the conductor part and the capacitance element constitute a delay circuit in which one wavelength of high frequency waves rides around the coil, and the angle in the circumferential direction of the coil is set by θ.
When, the current distribution! (θ) is slnθ or eO
Proportional to 3θ. This makes it possible to generate a uniform high-frequency magnetic field inside the coil, and also equalizes the detection sensitivity of magnetic resonance signals, allowing close contact with the region of interest, which has a higher S
/N is obtained. If this birdcage-shaped coil could be constructed as a double-tuned high-frequency coil, it would be possible to equalize the high-frequency magnetic field at two frequencies and the detection sensitivity of magnetic resonance signals, which would be extremely useful. A double tuned high frequency coil has not been proposed.
（発明が解決しようとする課題）
このように従来の高周波コイルでは、２種の周波数にお
いて高周波磁場の均一化と、磁気共鳴信号の検出感度の
均一化を得ることが難しいという問題があった。(Problems to be Solved by the Invention) As described above, the conventional high-frequency coil has a problem in that it is difficult to equalize the high-frequency magnetic field and the detection sensitivity of magnetic resonance signals at two different frequencies.
本発明は、２８の周波数において均一な高周波磁場を発
生でき、また磁気共鳴信号を均一な感度で検出できる磁
気共鳴装置用二重同調高周波コイルを提供することを目
的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a double-tuned high-frequency coil for a magnetic resonance apparatus that can generate a uniform high-frequency magnetic field at 28 frequencies and detect magnetic resonance signals with uniform sensitivity.
［発明の構成］
（課題を解決するための手段）
本発明は、所定の間隔で対向配置された一対のループ状
導体と、これら一対のループ状導体間にループ状導体の
長手方向に離間した複数の点で接続された複数の連絡導
体とを基本構成とする高周波コイルにおいて、一対のル
ープ状導体の各々の連絡導体の接続点相互間に並列共振
用キャパシタンス素子をそれぞれ接続し、複数の連絡導
体の途中にそれぞれ直列共振用キャパシタンス素子を挿
入するか、または一対のループ状導体の各々の連絡導体
の接続点相互間に直列に直列共振用キャパシタンス素子
を挿入し、複数の連絡導体にそれぞれ並列に並列共振用
キャパシタンス素子を接続したことを特徴とする。ルー
プ状導体の形状は閉ループ状でもよいし、両端が開放の
ループ状であってもよい。[Structure of the Invention] (Means for Solving the Problems) The present invention includes a pair of loop-shaped conductors that are arranged opposite to each other at a predetermined interval, and a pair of loop-shaped conductors that are spaced apart in the longitudinal direction of the loop-shaped conductors. In a high-frequency coil that has a basic configuration of multiple connecting conductors connected at multiple points, parallel resonance capacitance elements are connected between the connection points of each connecting conductor of a pair of loop-shaped conductors, and multiple connecting conductors are connected at multiple points. Either insert a series resonance capacitance element in the middle of each conductor, or insert a series resonance capacitance element in series between the connection points of each connecting conductor of a pair of loop-shaped conductors, and connect them in parallel to each of the multiple connecting conductors. It is characterized in that a parallel resonance capacitance element is connected to the . The shape of the loop-shaped conductor may be a closed loop shape or a loop shape with both ends open.
（作 用）
本発明の高周波コイルは、共振周波数より高い周波数領
域で容量性、低い周波数領域で誘導性を示すＬＣ並列共
振回路と、共振周波数より高い周波数領域で誘導性、低
い周波数領域で容量性を示すＬＣ直列共振回路を含むこ
とにより、コイル全体としては２種類の共振周波数を持
つ。そして、この高周波コイルはその形状から従来の鳥
かご型コイルと同様に、高周波磁場の均−性及び磁気共
鳴信号検出感度の均一性に優れた特性が得られる。(Function) The high frequency coil of the present invention has an LC parallel resonant circuit that is capacitive in a frequency range higher than the resonant frequency and inductive in a lower frequency range. The coil as a whole has two types of resonant frequencies by including an LC series resonant circuit that exhibits characteristics. Due to its shape, this high-frequency coil has excellent characteristics in the uniformity of the high-frequency magnetic field and the uniformity of magnetic resonance signal detection sensitivity, similar to the conventional birdcage-shaped coil.
（実施例）
以下、図面を２照して本発明の詳細な説明する。まず、
本発明による磁気共鳴装置用二重同調高周波コイルを説
明する前に、第５図を用いて磁気共鳴装置の構成を説明
する。(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. first,
Before explaining the double-tuned high-frequency coil for a magnetic resonance apparatus according to the present invention, the configuration of the magnetic resonance apparatus will be explained using FIG.
第５図において、静磁場磁石１０１及び勾配磁場生成コ
イル１０２は、システムコントローラ１０５により制御
される励磁用電源１０３及び駆動回路１０４によってそ
れぞれ駆動され、侵台１０７上の被検体（例えば人体）
１０６に対して、−様な静磁場と、空間的に直交するｘ
、ｙ、ｚの三方向に磁場強度がそれぞれ変化する勾配磁
場を印加する。In FIG. 5, a static magnetic field magnet 101 and a gradient magnetic field generating coil 102 are driven by an excitation power source 103 and a drive circuit 104, respectively, which are controlled by a system controller 105.
106, -like static magnetic field and spatially orthogonal x
A gradient magnetic field whose magnetic field strength changes in three directions, , y, and z, is applied.
被検体１０６にはさらにシステムコントローラ１０５の
制御の下で、送信部１０８からの高周波信号により送信
用プローブコイル１０９から高周波磁場が印加される。Further, under the control of the system controller 105 , a high-frequency magnetic field is applied to the subject 106 from a transmitting probe coil 109 based on a high-frequency signal from a transmitter 108 .
一方、被検体１０６によって発生される磁気共鳴信号（
ＦＩＤ信号またはエコー信号）は、受信用プローブコイ
ル１１０によって検出され、受信部１１１で増幅及び検
波された後、システムコントローラ１０５の制御の下で
データ収集部１１２に送られる。データ収集部１１２で
は受信部１１１を介して入力された磁気共鳴信号をシス
テムコントローラ１０５の制御の下で収集し、それをＡ
／Ｄ変換′５（図示せず）によりサンプリングしディジ
タル化した後、電子計算機１１３へ送る。On the other hand, the magnetic resonance signal (
The FID signal or echo signal) is detected by the receiving probe coil 110, amplified and detected by the receiving section 111, and then sent to the data collecting section 112 under the control of the system controller 105. The data collection unit 112 collects the magnetic resonance signals input through the reception unit 111 under the control of the system controller 105, and sends them to A.
After being sampled and digitized by /D conversion '5 (not shown), it is sent to the computer 113.
７ｈ子計算機１１３はコンソール１１４により制御され
、データ収集部１１２から人力されたＦＩＤ信号やエコ
ー信号のサンプリングデータについてフーリエ変換を行
なうことにより、画像データまたは化学シフトスペクト
ルデータを得る。The 7h child computer 113 is controlled by the console 114, and obtains image data or chemical shift spectrum data by performing Fourier transform on the sampling data of the FID signal and echo signal manually input from the data collection unit 112.
また、電子計算機１１３はシステムコントローラ１０５
の制御をも行なう。電子計算機１１３により得られた画
像データまたは化学シフトスペクトルデータは、画像デ
イスプレィ１１５に供給されて表示される。Further, the electronic computer 113 is connected to the system controller 105
It also controls the Image data or chemical shift spectrum data obtained by the electronic computer 113 is supplied to an image display 115 and displayed.
ここで、本発明による二重同調高周波コイルは、送信用
プローブコイル１０９及び受信用プローブコイル１１０
のいずれか一方に使用されるか、または両方に共用され
る。Here, the double-tuned high-frequency coil according to the present invention includes a transmitting probe coil 109 and a receiving probe coil 110.
used for one or the other, or shared by both.
第１図は本発明の一実施例に係る二重同調高周波コイル
を示したものである。所定の間隔て対向配置された一対
のループ状導体１．２の間に、複数（この例では６本）
の線状の連絡導体３が接続されている。ループ状導体１
の連絡導体３の各−端が接続された接続点間には、並列
共振用キャパシタンス素子４が並列にそれぞれ接続され
、またループ状導体２の連絡導体３の各他端が接続され
た接続点間にも、同様に並列共振用キャパシタンス素子
５が並列にそれぞれ接続されている。一方、連絡導体３
の途中は分断されており、それらの分断部に連絡導体３
と直列に直列共振用キャパシタンス素子６がそれぞれ挿
入されている。FIG. 1 shows a double-tuned high-frequency coil according to an embodiment of the present invention. A plurality of (six in this example) conductors are connected between a pair of loop-shaped conductors 1.2 arranged oppositely at a predetermined interval.
A linear connecting conductor 3 is connected thereto. Loop conductor 1
A parallel resonance capacitance element 4 is connected in parallel between the connection points to which each end of the connection conductor 3 is connected, and the connection point to which each other end of the connection conductor 3 of the loop conductor 2 is connected. Similarly, parallel resonance capacitance elements 5 are connected in parallel between them. On the other hand, connecting conductor 3
It is divided in the middle, and connecting conductor 3 is connected to the divided part.
A series resonance capacitance element 6 is inserted in series with each other.
そして、複数の連絡導体３のうちのいずれかに、図示し
ない結合用導体や整合器を介して例えば第５図における
送信部１０８または受信部１１１が接続される。Then, for example, the transmitter 108 or the receiver 111 in FIG. 5 is connected to one of the plurality of connecting conductors 3 via a coupling conductor or matching device (not shown).
第２図は第１図の高周波コイルの一つのエレメントの等
価回路であり、Ｌｌはループ状導体１．２の連絡導体３
の接続点間のインダクタンス、Ｃ１は並列共振用キャパ
シタンス４，５の容量、Ｌｌは連絡導体３の各々のイン
ダクタンス、Ｃ２は直列共振用キャパシタンス素子６の
容量をそれぞれ示す。FIG. 2 is an equivalent circuit of one element of the high-frequency coil in FIG. 1, and Ll is the connecting conductor 3 of the loop conductor 1.2.
, C1 is the capacitance of the parallel resonance capacitances 4 and 5, Ll is the inductance of each of the connecting conductors 3, and C2 is the capacitance of the series resonance capacitance element 6.
Ｌｌ、 ＣＩによって並列共振回路が構成され、Ｌｌ、
Ｃ２によって直列共振回路が構成される。そして、第
２図のエレメントがＮ個（第１図では６個）梯子型に接
続され、高周波コイル全体として梯子型遅延回路を構成
している。この場合、梯子型遅延回路は所望の磁気共鳴
周波数における１／２波長または１波長分の遅延時間を
持ち、これにより高周波コイル全体に１／２波長または
１波長の定在波が乗るようになっている。A parallel resonant circuit is configured by Ll, CI, and Ll,
C2 constitutes a series resonant circuit. The elements shown in FIG. 2 are connected in a ladder shape (N elements are shown in FIG. 2, six in FIG. 1), and the high-frequency coil as a whole constitutes a ladder-type delay circuit. In this case, the ladder type delay circuit has a delay time of 1/2 wavelength or 1 wavelength at the desired magnetic resonance frequency, so that a standing wave of 1/2 wavelength or 1 wavelength rides on the entire high frequency coil. ing.
上記ｉ＆成において、Ｌｌ、 Ｃ１，Ｌｌ、 Ｃ２は所
望の２種の磁気共鳴周波数をω■、ωＬとすると、高い
方の周波数ω■でＬｌ、 ＣＩの並列共振回路が容量性
、Ｌｌ、 Ｃ２の直列共振回路が誘導性となり、また低
い方の周波数ω、でＬｌ、 ＣＩの並列共振回路が誘導
性、１．２． Ｃ２の直列共振回路が容量性となるよう
に選ばれる。従って、高周波コイルを構成する梯子型遅
延回路の特性は、周波数ωＩＩにおいては高域通過型特
性、周波数ωしにおいては低域通過型特性となる。この
場合、ωＨ１ωＬは次式のように表わされる。In the above i & formation, Ll, C1, Ll, C2 are the two desired magnetic resonance frequencies ω■, ωL. At the higher frequency ω■, the parallel resonant circuit of Ll, CI is capacitive, Ll, C2 The series resonant circuit of Ll and CI becomes inductive, and at the lower frequency ω, the parallel resonant circuit of Ll and CI becomes inductive, 1.2. The series resonant circuit of C2 is chosen to be capacitive. Therefore, the characteristic of the ladder type delay circuit constituting the high-frequency coil is a high-pass type characteristic at the frequency ωII, and a low-pass type characteristic at the frequency ω. In this case, ωH1ωL is expressed as in the following equation.
ωＮ−％管ττ
ωＬ’ｍ１ｌｌ璽；〒
・・・（１）
・・・（２）
ωｌ′″″ ０２′″″Ｌ２・Ｃ２Ｌｌ −ＣＩ
’
Ｎ二梯子型遅延回路のエレメント数
従来の鳥かご型コイルは、一つで高域通過型または低域
通過型のいずれか一方の特性しか持たない。この烏かご
型コイルを２種の周波数で用いるには、キャパシタンス
素子の容量可変範囲を大きくし、その容量値を瞬時に切
換えられるようにすればよいが、切換えのために多数の
スイッチを必要とし、価格が高くなるばかりでなく、コ
イルが大型化するという問題が生じる。ωN-% tube ττ ωL'm1ll;〒 ...(1) ...(2) ωl'""02'""L2・C2Ll -CI
'N2 Number of Elements in Ladder Delay Circuit A single conventional birdcage coil has only one of high-pass or low-pass characteristics. In order to use this squirrel cage coil at two different frequencies, the capacitance variable range of the capacitance element can be increased so that the capacitance value can be switched instantaneously, but this requires a large number of switches for switching. , the problem arises that not only the price increases, but also the coil becomes larger.
これに対し、本発明の高周波コイルは上記のように周波
数によって自動的に高域通過型または低域通過型のいず
れか一方の特性を選択的に持ち、二重同調コイルの作用
を果たすので、キャパシタンス素子の容量値を切換える
ための多数のスイッチ素子を必要としない。In contrast, the high-frequency coil of the present invention automatically has either high-pass type or low-pass type characteristics depending on the frequency as described above, and functions as a double-tuned coil. A large number of switch elements for switching the capacitance value of the capacitance element is not required.
また、本発明の二重同調コイルは各々の周波数ω１．．
ω、では従来の、ｌかご型コイルと全く同様に作用する
から、送信用プローブコイルとして用いるときは均一な
高周波磁場を発生でき、また受信用プローブコイルとし
て用いるときは磁気共鳴信号を均一な感度で検出するこ
とが可能であり、くら型コイルを用いた二重同調コイル
に比較して良好な特性が得られる。Moreover, the double-tuned coil of the present invention has each frequency ω1. ．．
At ω, it functions in exactly the same way as a conventional squirrel cage coil, so when used as a transmitting probe coil, it can generate a uniform high-frequency magnetic field, and when used as a receiving probe coil, it can generate magnetic resonance signals with uniform sensitivity. It is possible to detect this by using a double-tuned coil, which provides better characteristics than a double-tuned coil using a saddle-shaped coil.
第３図は本発明の他の実施例に係る二重同調高周波コイ
ルを示したもので、第１図の実施例とは逆に一対のルー
プ状導体ｌの連絡導体３の各一端が接続された接続点間
に直列共振用キャパシタンス素子７をそれぞれ直列に挿
入し、またループ状導体２の連絡導体３の各他端°が接
続された接続点間にも、同様に直列共振用キャパシタン
ス素子８をそれぞれ直列に挿入するとともに、連絡導体
３と並列に並列共振用キャパシタンス素子９をそれぞれ
接続している。また、第１図の実施例と同様に？ｊＺ数
の連絡導体３のうちのいずれかに、図示しない結合用導
体や整合器を介して例えば第５図における送信部１０８
または受信部１１１か接続される。FIG. 3 shows a double-tuned high-frequency coil according to another embodiment of the present invention, in which, contrary to the embodiment of FIG. 1, one end of each connecting conductor 3 of a pair of loop-shaped conductors l is connected. Series resonance capacitance elements 7 are inserted in series between the connection points, and series resonance capacitance elements 8 are similarly inserted between the connection points to which the other ends of the connecting conductors 3 of the loop conductor 2 are connected. are inserted in series, and a parallel resonance capacitance element 9 is connected in parallel with the connecting conductor 3. Also, similar to the embodiment shown in Fig. 1? For example, the transmitter 108 in FIG.
Alternatively, the receiving section 111 is connected.
第４図は第２図の高周波コイルの一つのエレメントの等
価回路であり、Ｌｌはループ状導体１．２の連絡導体３
の接続点間のインダクタンス、Ｃ３は直列共振用キャパ
シタンス７．８の容量、Ｃ２は連絡導体３の各々のイン
ダクタンス、Ｃ４は並列共振用キャパシタンス素子９の
容量をそれぞれ示す。FIG. 4 is an equivalent circuit of one element of the high-frequency coil in FIG. 2, and Ll is the connecting conductor 3 of the loop conductor 1.2.
, C3 is the capacitance of the series resonance capacitance 7.8, C2 is the inductance of each of the connecting conductors 3, and C4 is the capacitance of the parallel resonance capacitance element 9.
Ｌｌ、 Ｃ３によって直列共振回路、Ｃ２，Ｃ４によっ
て並列共振回路がそれぞれ構成され、第３図のエレメン
トがＮ個（第１図では６個）梯子型に接続されることに
より高周波コイル全体が梯子型遅延回路を構成している
。この梯子型遅延回路の遅延時間は、第１ｒＡの実施例
と同様に所望の磁気共鳴周波数における１／２波長また
は１波長分であり、高周波コイル全体に１／２波長また
は１波長の定在波が乗るようになっている。A series resonant circuit is formed by Ll and C3, and a parallel resonant circuit is formed by C2 and C4, and by connecting N elements (6 in Fig. 1) in a ladder form as shown in Fig. 3, the entire high frequency coil becomes a ladder form. It constitutes a delay circuit. The delay time of this ladder-type delay circuit is 1/2 wavelength or 1 wavelength at the desired magnetic resonance frequency, as in the first rA embodiment, and the standing wave of 1/2 wavelength or 1 wavelength is distributed throughout the high-frequency coil. is designed to be ridden.
この実施例の高周波コイルにおいては、所望の２種の磁
気共鳴周波数をω１１ 、ω、とすると、高い方の周波
数ω１１で旧、 Ｃ３の直列共振回路が誘導性、Ｃ２，
Ｃ４の並列共振回路が容量性となり、低い方の周波数ω
ＬでＬｌ、 Ｃ３の直列共振回路が容量性、Ｃ２，Ｃ４
の並列共振回路が誘導性となるように選ばれ、これによ
り高周波コイルを構成する梯子型遅延回路の特性は、周
波数ωＨにおいては低域通過型特性、周波数ω、におい
ては高域通過型特性となる。この場合、ω１９．ωＬは
次式のように表わされる。In the high frequency coil of this embodiment, if the two desired magnetic resonance frequencies are ω11 and ω, then at the higher frequency ω11, the series resonant circuit C3 is inductive, C2,
The parallel resonant circuit of C4 becomes capacitive, and the lower frequency ω
L is Ll, C3 series resonant circuit is capacitive, C2, C4
The parallel resonant circuit is selected to be inductive, so that the characteristics of the ladder-type delay circuit constituting the high-frequency coil are low-pass characteristics at frequency ωH and high-pass characteristics at frequency ω. Become. In this case, ω19. ωL is expressed as in the following equation.
（ＩＪ １１−Ｊ’乙を彊 −（３）ωＬ
−／；を可 ・・・（４）ω３＋ω４２
１ １
Ｃ″″ ２ ”２ＬＩＣ４’ ｓｉｎ’ ｘハｓ
ｉｎ”πハ＋４Ｌ１２ Ｃ４２” ｓｉｎ’ Ｗハエ１
ω３２− ω４２″″Ｌ２− Ｃ４Ｌｌ −Ｃ３゜
Ｎ：梯子型遅延回路のエレメント数
この実施例の高周波コイルにおいても、先の実施例の高
周波コイルと同様の作用効果がｉすられることはいうま
でもない。(IJ 11-J' Otsu wo Ki - (3) ωL
-/; possible...(4)ω3+ω42
1 1 C″″ 2 ``2LIC4'sin' xhas
in"πha+4L12 C42"sin' W fly1 ω32- ω42""L2- C4Ll -C3゜N: Number of elements in the ladder-type delay circuit The high-frequency coil of this example is similar to the high-frequency coil of the previous example. It goes without saying that the effects of i are affected.
なお、ループ状導体１，２が閉ループとなっているが、
両端が開放したループ状であってもよい。Although the loop-shaped conductors 1 and 2 are closed loops,
It may have a loop shape with both ends open.
その他、本発明は要旨を逸脱しない範囲で種々変形して
実施することができる。In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.
［発明の効果］
本発明による磁気共鳴装置用二重同調高周波コイルは、
２種の周波数において均一な高周波磁場を発生でき、ま
た磁気共鳴信号を均一な感度で検出することができる。[Effects of the Invention] The double-tuned high-frequency coil for magnetic resonance apparatus according to the present invention has the following features:
Uniform high-frequency magnetic fields can be generated at two different frequencies, and magnetic resonance signals can be detected with uniform sensitivity.
第１図は本発明の一実施例に係る磁気共鳴装置用二重同
調高周波コイルの構成図、第２図は第１図の高周波コイ
ルの一つのエレメントの等価回路図、第３図は本発明の
他の実施例に係る磁気共鳴装置用二重同調高周波コイル
の構成図、第４図は第３図の高周波コイルの一つのエレ
メントの等価回路図、第５図は本発明の高周波コイルか
使用される磁気共鳴装置の一例を示すブロック図である
。
１．２・・・ループ状導体、３・・・連絡導体、４゜５
・・・並列共振用キャパシタンス素子、６・・・直列共
振用キャパシタンス素子、７．８・・・直列共振用キャ
パシタンス素子、９・・・並列共振用キャパンタンス素
子。FIG. 1 is a configuration diagram of a double-tuned high-frequency coil for a magnetic resonance apparatus according to an embodiment of the present invention, FIG. 2 is an equivalent circuit diagram of one element of the high-frequency coil of FIG. 1, and FIG. 3 is a diagram of the present invention. FIG. 4 is an equivalent circuit diagram of one element of the high-frequency coil of FIG. 3, and FIG. 5 is a diagram showing the configuration of a double-tuned high-frequency coil for a magnetic resonance apparatus according to another embodiment of the present invention. FIG. 2 is a block diagram showing an example of a magnetic resonance apparatus. 1.2...Loop-shaped conductor, 3...Connecting conductor, 4゜5
... Capacitance element for parallel resonance, 6... Capacitance element for series resonance, 7.8... Capacitance element for series resonance, 9... Capantance element for parallel resonance.
Claims (2)
と、 前記一対のループ状導体間にループ状導体の長手方向に
離間した複数の点で接続された複数の連絡導体と、 前記一対のループ状導体の各々の前記連絡導体の接続点
相互間に並列に接続された並列共振用キャパシタンス素
子と、 前記複数の連絡導体の途中にそれぞれ直列に挿入された
直列共振用キャパシタンス素子とを備えたことを特徴と
する磁気共鳴装置用二重同調高周波コイル。(1) a pair of loop-shaped conductors arranged opposite to each other at a predetermined interval; a plurality of connecting conductors connected between the pair of loop-shaped conductors at a plurality of points spaced apart in the longitudinal direction of the loop-shaped conductors; and the pair of loop-shaped conductors. a parallel resonance capacitance element connected in parallel between connection points of the connection conductors of each of the loop-shaped conductors; and a series resonance capacitance element inserted in series in the middle of each of the plurality of connection conductors. A double-tuned high-frequency coil for magnetic resonance equipment, characterized by:
と、 前記一対のループ状導体間にループ状導体の長手方向に
離間した複数の点で接続された複数の連絡導体と、 前記一対のループ状導体の各々の前記連絡導体の接続点
相互間に直列に接続された直列共振用キャパシタンス素
子と、 前記複数の連絡導体にそれぞれ並列に接続された並列共
振用キャパシタンス素子とを備えたことを特徴とする磁
気共鳴装置用二重同調高周波コイル。(2) a pair of loop-shaped conductors facing each other at a predetermined interval; a plurality of connecting conductors connected between the pair of loop-shaped conductors at a plurality of points spaced apart in the longitudinal direction of the loop-shaped conductors; and the pair of loop-shaped conductors. a series resonance capacitance element connected in series between connection points of the connection conductors of each of the loop-shaped conductors; and a parallel resonance capacitance element connected in parallel to each of the plurality of connection conductors. A double-tuned high-frequency coil for magnetic resonance equipment featuring:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63246436A JP2714044B2 (en) | 1988-09-30 | 1988-09-30 | Double tuning high frequency coil for magnetic resonance equipment. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63246436A JP2714044B2 (en) | 1988-09-30 | 1988-09-30 | Double tuning high frequency coil for magnetic resonance equipment. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0293387A true JPH0293387A (en) | 1990-04-04 |
| JP2714044B2 JP2714044B2 (en) | 1998-02-16 |
Family
ID=17148446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63246436A Expired - Lifetime JP2714044B2 (en) | 1988-09-30 | 1988-09-30 | Double tuning high frequency coil for magnetic resonance equipment. |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2714044B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5081418A (en) * | 1990-04-30 | 1992-01-14 | General Electric Company | Method and apparatus for tuning an nmr field coil |
| US5196797A (en) * | 1990-10-31 | 1993-03-23 | Toshiba America Mri, Inc. | Method of correcting an asymmetry in an NMR radio frequency coil and an improved radio frequency coil having N-fold symmetry and reduced eddy current |
| JP2008295737A (en) * | 2007-05-31 | 2008-12-11 | Hitachi Ltd | Magnetic field coil, and magnetic resonance imaging device |
| JP2010099473A (en) * | 2008-10-23 | 2010-05-06 | General Electric Co <Ge> | Hybrid birdcage-tem radio frequency (rf) coil for multinuclear mri/mrs |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6391911B2 (en) | 2013-01-23 | 2018-09-19 | キヤノンメディカルシステムズ株式会社 | Magnetic resonance imaging apparatus and RF coil apparatus |
-
1988
- 1988-09-30 JP JP63246436A patent/JP2714044B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5081418A (en) * | 1990-04-30 | 1992-01-14 | General Electric Company | Method and apparatus for tuning an nmr field coil |
| US5196797A (en) * | 1990-10-31 | 1993-03-23 | Toshiba America Mri, Inc. | Method of correcting an asymmetry in an NMR radio frequency coil and an improved radio frequency coil having N-fold symmetry and reduced eddy current |
| JP2008295737A (en) * | 2007-05-31 | 2008-12-11 | Hitachi Ltd | Magnetic field coil, and magnetic resonance imaging device |
| JP2010099473A (en) * | 2008-10-23 | 2010-05-06 | General Electric Co <Ge> | Hybrid birdcage-tem radio frequency (rf) coil for multinuclear mri/mrs |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2714044B2 (en) | 1998-02-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0301232B1 (en) | Dual frequency NMR surface coil | |
| US6043658A (en) | MR apparatus including an MR coil system | |
| US4783641A (en) | NMR radio frequecny field coil with distributed current | |
| EP0554388B1 (en) | A radio frequency volume resonator for nuclear magnetic resonance | |
| US6316941B1 (en) | Open view quadrature birdcage coil | |
| CN100437137C (en) | Method and equipment for decoupling for magnetic resonance imaging radio-frequence detector array | |
| EP0336728B1 (en) | Apparatus for tuning an NMR field coil | |
| JPS63111846A (en) | Nmr apparatus | |
| US5202635A (en) | Radio frequency volume resonator for nuclear magnetic resonance | |
| US5194811A (en) | Radio frequency volume resonator for nuclear magnetic resonance | |
| JPH057564A (en) | Magnetic resonance device | |
| JPS61124854A (en) | Nuclear magnetic resonance imaging antenna sub-system with plurality of non-orthogonal surface coil | |
| JP2001145612A (en) | Rf coil for device and method for magnetic resonance | |
| JPH0820496B2 (en) | Method for tuning an NMR field coil | |
| EP0177855A2 (en) | Radio frequency field coil for nmr | |
| US4792759A (en) | Multi-frequency surface probe | |
| JPH0213871A (en) | Double tuning circuit for centralized/ decentralized electrostatic capacitance observation coil | |
| JPH0578339B2 (en) | ||
| RU2525747C2 (en) | Noise matching in coupled antenna arrays | |
| JPH0293387A (en) | Double tuning high frequency coil for magnetic resonance apparatus | |
| JP3517019B2 (en) | Magnetic resonance diagnostic equipment | |
| Ghaly et al. | Design and modeling of a radiofrequency coil derived from a helmholtz structure | |
| JP3699968B2 (en) | Multiple tuning RF coil | |
| JP3171881B2 (en) | High frequency probe for magnetic resonance imaging apparatus and magnetic resonance imaging apparatus | |
| JPH04212330A (en) | Magnetic resonance video device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081031 Year of fee payment: 11 |
|
| EXPY | Cancellation because of completion of term |