CN102650684A

CN102650684A - Magnetic resonance imaging radio-frequency coil device

Info

Publication number: CN102650684A
Application number: CN2011100471006A
Authority: CN
Inventors: 王秀彬; 景宏美; 陈建中; 陈郁韩
Original assignee: Affiliated Hospital of Nantong University
Current assignee: Affiliated Hospital of Nantong University
Priority date: 2011-02-23
Filing date: 2011-02-23
Publication date: 2012-08-29

Abstract

The invention discloses a radio frequency coil device for magnetic resonance imaging. The radio frequency coil device includes a coil hollow cylinder skeleton, a coil circuit and a cylindrical shell. The coil circuit is placed in the slot of the hollow cylinder skeleton, and four surface coils with the same performance are applied, and two of the coils are cross-connected to form two sets of cross-shaped coils, and the four surface coils are evenly surrounded on the hollow cylinder skeleton. This can have a higher SNR. In order to overcome the mutual inductance between the coils, in order to decouple the RF coil device, capacitors and decoupling circuits are used to connect the coils, and the two sets of coils are partially overlapped.

Description

Magnetic resonance imaging serial radio frequency coil device

Technical field

The present invention relates to a kind of magnetic resonance imaging system, specifically, the present invention relates to serial radio frequency coil device in the magnetic resonance imaging.

Background technology

Magnetic resonance imaging (Magnetic Resonace Imaging MRI) is to utilize atomic nucleus in magnetic field, to resonate to produce a kind of technology that signal undergoes reconstruction and forms images.Use the material that can produce net spin (like the proton in the human body ¹H), because of proton belt positive electricity, and spin motion, produce little magnetic moment, like same small magnetic needle, the direction of small magnetic needle is irregular, but puts into level or vertical main field B uniformly ₀In after, it does the precession campaign, precession frequency is by Larmor theorem ω ₀=γ B ₀Decision, most small magnetic needle can be arranged along the direction of externally-applied magnetic field again, and produces magnetic moment M ₀Add radio frequency (Radio Frequency RF) B according to More's theorem ₁Excite, and make magnetic moment M ₀Change.B ₁Direction must be perpendicular to B ₀, the radio frequency B that adds ₁After a period of time stops; The proton that is excited progressively discharges the energy that is absorbed; With a coil energy measuring that discharges is come out; Be called free induction decay signal (Free Induction Decay FID), the atomic nucleus that then is excited can progressively discharge what absorbed, the state before its phase place and energy level all return to and excite.And the energy that receives these releases is to use various radio-frequency coils.This signal contains the information of human body proton, is used for imaging.

Can find out that from above radio-frequency coil plays an important effect the magnetic resonance imaging system.He is mainly used in the transmitting RF pulse, accepts free induction signal (FID).The performance quality of coil directly influences the quality of image.

(signal to noise ratio, SNR), in the diagnosis of medical image, surface coils can be close to patient's diseased region, has higher resolution because of surface coils has very high s/n ratio.But the magnetic field that surface coils produced is inhomogeneous, and the degree of depth that penetrates is limited.

In order to overcome the shortcoming of surface coils, the series connection of application surface coil evenly is centered around on hollow cylinder or the hollow ellipse cylinder, so both higher SNR can be arranged, and the degree of depth that can obtain to penetrate preferably again improves the magnetic field homogeneity that coil produced.Improve coil quality factor (Q).For the parallel radio frequency coil imaging technique that uses with magnetic resonance imaging at present matches,, be named as magnetic resonance imaging serial radio frequency coil device with the tandem arrangement of a plurality of coils.

Summary of the invention

The present invention provides a kind of novelty and coil device simple in structure, and the problem that solve is that design improves the high s/n ratio (SNR) of coil, improves the magnetic field homogeneity that coil produced.Use the consistent surface coils of 4 performances; Wherein two coils intersect continuous; Form two groups of chiasma type coils; Fig. 1 i.e. (20) forms two groups of chiasma type coils with (50) and (30) and (40), in order to overcome the mutual inductance between the coil, coil (20) is overlapped with (30) and (40) and (50) carry out uncoupling.

Description of drawings

Characteristics of the present invention are further described with implementing in conjunction with accompanying drawing.

Fig. 1 is a string line coil structures volume rendering synoptic diagram of the present invention.

Fig. 2 is the appearance figure of serial coil of the present invention.

Embodiment

Fig. 2 is that the appearance figure (10) of serial coil of the present invention makes the skeleton of coil for hollow cylinder, and (70) are coil case.In this embodiment, two circular grooves are opened along damaged surface circular arc direction in the right cylinder two ends, along the cylinder direction four grooves are set again.Fig. 1 is a string line coil structures volume rendering synoptic diagram of the present invention, (40) two coils of coil (20) and coil (50) and coil (30) and coil is intersected link to each other, and forms two groups of coils and is positioned in the groove of (10), and two groups of coil tandems are got up.Coil (20) and coil (30) and coil (40) are overlapped with coil (50).The characteristic of each small coil is identical, and (60) are coil radiofrequency signal output interface, uses electric capacity between coil and is coupled with the circuit of uncoupling.

In the present embodiment, coil is positioned in the groove of hollow cylinder skeleton, column type (70) the shell protection that outside employing is bigger, and the size of shell just in time can make placement coil hollow cylinder skeleton just in time combine closely, and fixes with no magnetic material.Open the groove of four perforations again in the centre of four coils, help ventilating and reducing loss.

The relevant scientific and technical personnel in this technical field can make amendment to the profile of Fig. 1 and Fig. 2, can change other shape into according to application need with getting hollow cylinder in the present embodiment, like the hollow ellipse cylinder, and hollow four-side body etc.And the respective coil electric wire made certain deformation, help actual demand.

Relevant scientific and technical personnel in this technical field add fixed base plate, fixed support and the fixed band of coil to the scheme of Fig. 2, help concrete practical and convenient purpose to reach.

Can on the basis that does not break away from principle of the present invention, make up many embodiments, except that the needs that right requires, the invention is not restricted to desired specific embodiment in the instructions.

Claims

1. A serial coil device applied to magnetic resonance imaging, the main feature is that the serial coil device comprises: a coil inner shell, a coil outer shell, the coil inner shell is a hollow cylinder, and the coil inner shell The shell arranges the coil wires. The coil casing functions as fixation and protection.

2. The serial coil device according to claim 1, characterized in that there are 4 surface coils with the same performance.

3. The serial coil device according to claim 2, wherein two coils are cross-connected to form two sets of coils, and the two sets of coils are connected in series.

4. The serial coil device according to claims 1, 2, and 3, wherein the hollow cylinder of the coil inner shell is replaced by a hollow elliptical cylinder and a hollow tetrahedron.