CN1786730A - Apparatus of animal radio-frequency coil for magnetic resonance imaging system - Google Patents
Apparatus of animal radio-frequency coil for magnetic resonance imaging system Download PDFInfo
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- CN1786730A CN1786730A CN 200410089210 CN200410089210A CN1786730A CN 1786730 A CN1786730 A CN 1786730A CN 200410089210 CN200410089210 CN 200410089210 CN 200410089210 A CN200410089210 A CN 200410089210A CN 1786730 A CN1786730 A CN 1786730A
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Abstract
The invention relates to animal special magnetic resonance imaging radio frequency coil device. It includes coil supporting shell, coil circuit, coil shell, and animal fixing device. The coil shell is divided into two parts; one is inner shell body which is cylindrical form; the other is inner shell end which is hemispherical shell form. They are fixed together. The coil circuit is birdcage type coil circuit structure. And it is pasted on the inner shell. Shell is fixed by antimagnetic screw and inner shell to protect the coil circuit. Experiment animal fixing device is set in the inner shell cavity. The animal is fixed on the fixing device to use coil offered even radio frequency magnetic field to stimulate nuclear magnetic resonance or/and detect animal transmitted nuclear magnetic resonance to do magnetic resonance imaging.
Description
Technical field
The present invention relates generally to magnetic resonance imaging system.Particularly, the present invention relates to the coil device that is used for animal used as test is carried out imaging that in magnetic resonance imaging system, uses.
Background technology
Nuclear magnetic resonance image system (MRI) uses the uniform strong magnetic field of autonomous magnetic system (to be called the main field-B of MRI system
0) spin polarizes to the hydrogen nuclei in the human body.Magnetic polarization nuclear spin produces magnetic moment i in human body.This magnetic moment points to the main field direction when stable state, if do not encourage disturbance then can not produce Useful Information.
(be called and excite magnetic field or B by uniform radio frequency (RF) magnetic field
1Magnetic field) excite magnetic moment to produce nuclear magnetic resonance (NMR) signal, thereby obtain nuclear magnetic resonance image system (MRI) data.Radio-frequency sending coil produces B at the image-region of required detection
1Magnetic field, this radio-frequency sending coil is driven by the computer-controlled radiofrequency launcher that is subjected to that adopts power amplifier.In excitation process, the nuclear spin system absorbs energy, makes magnetic moment around the precession of main field direction.After exciting, the magnetic moment of precession will experience free induction decay (FID), discharge the energy of its absorption and return stable state.In free induction decay (FID), use to be placed near the received RF coil that human body is excited the part and to survey nuclear magnetic resonance (NMR) signal.This nuclear magnetic resonance (NMR) signal is second voltage (or electric current) that is in the received RF coil, and this voltage (or electric current) is induced by the precession magnetic moment of tissue.The received RF coil can be that transmitting coil itself also can be the absolute coil that receives only radiofrequency signal.Produce the extra-pulse gradient magnetic by the gradient coil that is integrated in the main field system, optionally excite the interior atomic nucleus of voxel of required position, and can carry out frequency coding and phase encoding to signal, thereby determine its volume coordinate, final through Fourier transform, set up a complete nuclear magnetic resonance image.
In nuclear magnetic resonance image system (MRI), the homogeneity in the magnetic field that transmitting coil and receiving coil produced is a key factor that obtains high quality graphic.In common nuclear magnetic resonance image system, adopt whole-body radio frequency coil to obtain best exciting field homogeneity usually.Whole-body radio frequency coil is a radio-frequency coil maximum in the system.But, if use bigger coil to receive simultaneously, then can produce lower signal to noise ratio (snr), this mainly is because such receiving coil is far away with the signal generation tissue distance that participates in imaging.Because in nuclear magnetic resonance image system (MRI), the most important thing is high s/n ratio (SNR), receive to improve the signal to noise ratio (snr) of required probe portion so often adopt special-purpose coil to carry out radio frequency.
In practicality, design preferable special-purpose radio-frequency coil and should have following function: high s/n ratio, good homogeneity, the high-altitude charge material amount factor (Q) of resonant circuit.In addition, coil device must be designed to be suitable for doctor's operation and have comfort level, and provides the protection barrier between patient and radio frequency electric equipment.A kind of method that improves signal to noise ratio (snr) is that quadrature receives.In this method, by cover two of required search coverage mutually independently coil survey two signals.The radiofrequency signal signal to noise ratio (S/N ratio) that adopts quadrature to receive is when adopting single linearity coil situation
Doubly.Birdcage coils is a kind of quadrature coil commonly used, and especially with respect to surface coils commonly used, the magnetic field homogeneity of birdcage coils is good especially.Another method that improves signal to noise ratio (S/N ratio) is the phased-array coil technology.For imaging is carried out in a bigger zone, if use single bigger coil, the noise of the All Ranges that coil covered all enters coil, so poor signal to noise.If the use phased-array technique uses a plurality of independently small coils to cover this zone together, just can enter coil owing to only close on the noise of the very zonule of coil, therefore can improve signal to noise ratio (S/N ratio) effectively.
Animal coil is meant the toy that uses in biology or medical science, and as mouse, rabbit etc. carry out the radio-frequency coil of magnetic resonance imaging.Generally, movable in the MRI process in order to prevent animal used as test, need carry out anaesthetic treatment to animal.Have great significance but the animal that does not carry out anaesthetic treatment is carried out MRI research,, just must under the situation that animal regains consciousness, carry out such as very popular at present cerebral function imaging.
In addition, for common birdcage coils, in the place near coil edge, magnetic field is about about 1/2 of central magnetic field intensity usually, and the inhomogeneous of magnetic field will cause the inhomogeneous of imaging, thereby influence image quality to a great extent.And the transmitting coil of system band itself is very big, and the animal used as test volume is very little, and with the transmitting coil of system itself, emission efficiency is low, poor signal to noise.
Summary of the invention
At the problems referred to above, the present invention has designed a kind of coil device that the experiment toy is carried out magnetic resonance imaging that is exclusively used in, and described coil device comprises: coil inner casing, coil circuit, coil case and animal fixing device.The coil inner casing is divided into two parts, i.e. inner casing main body and inner casing head.The inner casing main body is cylindric, an end opening, and the other end is fixedlyed connected with the inner casing head of hemisphere hull shape.In addition, in described coil device, also be provided with the animal fixing device that to pump in the middle of the formed cylindrical cavity of shell in coil, be used to place animal used as test, and under the situation of needs, fix the animal used as test that does not carry out anaesthetic treatment.On described coil inner casing, stick circuit through the birdcage coils of distortion, and, utilize birdcage coils to have the characteristics of excellent magnetic field homogeneity through distortion, this coil design becomes the transmit-receive sharing coil, thereby improve the efficient that coil transmits and receives effectively, improve image quality.
According to another aspect of the present invention, described coil head can be replaced with cone shape, half elliptic or other can hold the shape of animal head.In addition, the circuit of coil can adopt toroid winding and the combined mode of saddle-type coil to form quadrature coil or phased-array coil.
Description of drawings
Fig. 1 is the inner casing structural representation according to apparatus of animal radio-frequency coil of the present invention.
Fig. 2 is the structural representation according to the birdcage coil of the process distortion of apparatus of animal radio-frequency coil of the present invention
Fig. 3 is the structural representation of traditional birdcage coil.
The comparison of the Distribution of Magnetic Field figure of the birdcage coil of Fig. 4 tradition birdcage coil and process distortion.
Fig. 5 is the synoptic diagram that is used for fixing the animal fixing device of animal according to of the present invention.
Fig. 6 is the appearance figure according to animal coil of the present invention
Embodiment
To describe embodiments of the invention in detail by illustrated method below, in the process that is described with reference to the accompanying drawings, identical Reference numeral is described same or analogous parts among the different figure.
Fig. 1 is the inner casing structural representation according to apparatus of animal radio-frequency coil of the present invention.As shown in Figure 1, interior shell structure comprises inner casing main body and inner casing head, and the inner casing main body is a columnar hollow cavity; In the present embodiment, the inner casing head is the hemisphere hull shape, and the spherical shell internal diameter equates that with the internal diameter of inner casing main body both are fixed together, and forms one one end opening, and the cavity of end sealing is to hold animal used as test.In addition, because the difference of the body volume of animal used as test, the internal diameter of described cylindrical cavity can have very big variation according to actual needs.
The shell outside sticks the circuit of coil in coil.What in this embodiment, coil circuit adopted is that Fig. 2 is its synoptic diagram through the birdcage coils structure of distortion.Traditional birdcage coils as shown in Figure 3, elements such as its inductance, electric capacity are evenly distributed on the surface cylindraceous.This is a kind of quadrature coil structure comparatively commonly used, and its biggest advantage is that portion magnetic field is more even in coil.But in place near coil edge, magnetic field on its axis just approximates 1/2 of magnetic field intensity on the inner axis, that is to say, in submarginal place, magnetic field intensity is very inhomogeneous, this also just means that coil surveys the sensitivity of MRI signal herein and be about inner 1/2, if and this coil is used as the transmit-receive sharing coil, because it is inner 1/2 that the transmit signal strength of edge and the signal sensitivity when accepting all approximate, therefore total signal intensity is about inner 1/4.This good advantage of magnetic field homogeneity that just makes that birdcage coil had is had a greatly reduced quality.For this reason, deviser of the present invention has designed a kind of new birdcage coils structure here, promptly as shown in Figure 2, one end of traditional birdcage coil is shunk, because after shrinking, current lead (being inductance) is tending towards concentrated, and the magnetic field intensity that coil shrinks on the axis of an end is enhanced, thereby makes that the homogeneity in magnetic field is remedied.Fig. 4 is the comparison of the birdcage coil magnetic field intensity effect of traditional birdcage coil and process distortion.Transverse axis represents that along the position of the axis of these two kinds of coils the length of two coils is 70 (arbitrary units), and the left and right edges of coil lays respectively at 20 and 70 on coordinate axis.The longitudinal axis is the magnetic field intensitys of two kinds of coils on axis.Dotted line is represented among the figure be exactly magnetic field intensity on the axis of traditional birdcage coil with the variation of position, solid line is represented is through the variation of the magnetic field intensity on the axis of the birdcage coil of above-mentioned distortion with the position.As can be seen, at the two ends of coil, promptly horizontal ordinate is 20 and 90 place, and the magnetic field intensity of traditional birdcage coil is about 1/2 of coil inside magnetic field intensity, and for process distortion birdcage coil, the magnetic field intensity of the end that its loop construction shrinks approximates 80% of inside.Therefore as can be seen, shrink through the end with traditional birdcage coil, the homogeneity in the magnetic field of coil inside has obtained improving effectively.And, because the end that coil shrinks in actual the use is the brain position of animal used as test normally, and in general, the size of animal used as test brain is much smaller than the size of health, so loop construction contraction herein will be helped improving fill factor, curve factor, reduce signal to noise ratio (S/N ratio), thereby improve image quality, this will be very important in the cerebral function imaging of animal.
In the formed cavity of coil device inner casing, be provided with the fixedly stationary installation of animal used as test.What adopt in the middle of this embodiment is as shown in Figure 5 fixed head.Carrying out anaesthetic treatment to dead animal or to animal, making under the situation of its LOM, and animal can be placed on and directly carry out the magnetic resonance imaging experiment on the fixed head.If carrying out cerebral function imaging etc. needs to keep by the experiment of animal used as test waking state, then can animal used as test be placed on this fixed head earlier, be drilled with a lot of apertures on the fixed head, can be used for firmly being bundled in fixed head on flexible articles such as ropes animal for research, make its at will activity, so just can eliminate motion artifacts, obtain high-quality MRI image.This fixed head can be extracted out in the middle of the formed cavity of coil inner casing before experiment, will be placed or be fixed on by animal used as test on this fixed head, pushes cavity then, can experimentize.
The inner casing of coil device has been owing to sticked coil circuit, so the outside need effect that has shell to play protection and support.In the middle of present embodiment, the shaped upper part of the shell of coil device is similar to the coil inner casing, and just size is bigger, and the inner casing of coil is filled in the middle of the shell, fixes with non-magnetic screw then; The bottom of the shell of coil device mainly plays a part to support whole winding, and main body is the tetragonal body shape, and seamlessly transits in top, and the bottom surface is level and smooth, is convenient to place.Fig. 6 assembles effect synoptic diagram afterwards for the whole winding device.
Those of ordinary skill in the art also can make certain modification or replacement and not deviate from spirit of the present invention and principle the design of the birdcage coils of the inner casing of as shown in Figure 1a coil and distortion shown in Figure 2, such as can be according to actual needs becoming half elliptic, cone shape or other can hold required shape of zoologizeing head the head design of inner casing, and in view of the above the birdcage coil that sticks is thereon made corresponding deformation, make this design can in coil head, form uniform magnetic field, to carry out magnetic resonance imaging clearly.
Those of ordinary skill in the art also can do certain modification or replacement and not deviate from spirit of the present invention and principle the design of the birdcage coils of as shown in Figure 2 distortion, can adopt toroid winding commonly used or saddle-type coil such as associating at an easy rate, perhaps they are combined to form quadrature coil or phased-array coil and obtain magnetic field homogeneity and higher coil sensitivity preferably.
Those of ordinary skill in the art also can do certain modification or replacement to animal used as test fixed form as shown in Figure 5 and not deviate from spirit of the present invention and principle, be similar to clip such as adopting, handcuffss, modes such as pin handcuffs or necklace fix animal used as test, prevent by the animal used as test activity to reach, eliminate the purpose of motion artifacts.
Though quote certain embodiments and application thereof here invention disclosed herein has been described, but those of ordinary skills can make various corrections and variation to these embodiment under the situation of the spirit and scope of claims of the present invention.
Claims (11)
1. magnetic resonance imaging system (MRI) coil device that is used for detecting animal is characterized in that described coil device comprises:
The coil inner casing, described coil inner casing is made up of coil inner casing main body and coil inner casing head, and described coil inner casing main body is a cylindrical shape, an end opening, the fixedly connected described coil inner casing head of the other end, described coil inner casing head is the hemisphere hull shape;
On described coil inner casing, sticked coil circuit;
Be provided with animal fixing device in the formed inside cavity of described coil inner casing.
2. coil device as claimed in claim 1 is characterized in that described coil head replaces with cone shape.
3. coil device as claimed in claim 1 is characterized in that described coil head replaces with half elliptic.
4. as claim 1,2 or 3 described coil devices, it is characterized in that described animal fixing device is for pumping formula.
5. as claim 1,2 or 3 described coil devices, it is characterized in that, be provided with the stationary installation of head, health and four limbs in the described animal fixing device.
6. as claim 1,2 or 3 described coil devices, it is characterized in that described coil circuit is the birdcage coils structure.
7. as claim 1,2 or 3 described coil devices, it is characterized in that described coil circuit is the birdcage coils structure through distortion.
8. as claim 1,2 or 3 described coil devices, it is characterized in that described coil circuit is the quadrature coil that toroid winding is combined to form.
9. as claim 1,2 or 3 described coil devices, it is characterized in that described coil circuit is the quadrature coil that saddle-type coil is combined to form.
10. as claim 1,2 or 3 described coil devices, it is characterized in that described coil circuit is the phased-array coil that toroid winding is combined to form.
11., it is characterized in that described coil circuit is the phased-array coil that saddle-type coil is combined to form as claim 1,2 or 3 described coil devices.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN 200410089210 CN1786730A (en) | 2004-12-08 | 2004-12-08 | Apparatus of animal radio-frequency coil for magnetic resonance imaging system |
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| CN 200410089210 CN1786730A (en) | 2004-12-08 | 2004-12-08 | Apparatus of animal radio-frequency coil for magnetic resonance imaging system |
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| CN1786730A true CN1786730A (en) | 2006-06-14 |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010083631A1 (en) * | 2009-01-23 | 2010-07-29 | 梅州康立高科技有限公司 | Magnetic therapy equipment for animal experiment |
| CN103116146A (en) * | 2013-02-26 | 2013-05-22 | 江苏美时医疗技术有限公司 | Head radiofrequency coil for magnetic resonance imaging system |
| CN103116147A (en) * | 2013-02-26 | 2013-05-22 | 江苏美时医疗技术有限公司 | Knee radiofrequency coil for magnetic resonance imaging system |
| CN103357115A (en) * | 2012-04-09 | 2013-10-23 | 上海市计划生育科学研究所 | Rodent-animal model manufacturing and application |
| CN105286864A (en) * | 2014-06-30 | 2016-02-03 | 中国科学院上海生命科学研究院 | Integrated coil, special for non-human primates, in magnetic resonance imaging system |
| CN106923827A (en) * | 2015-12-31 | 2017-07-07 | 中国科学院深圳先进技术研究院 | The coils special of the HIFU Treatment animal tumor guided by MRI |
| CN107884732A (en) * | 2016-09-30 | 2018-04-06 | 西门子(深圳)磁共振有限公司 | MR imaging apparatus, radio-frequency coil and its manufacture method |
| CN109696641A (en) * | 2018-12-29 | 2019-04-30 | 佛山瑞加图医疗科技有限公司 | Receiving coil apparatus and magnetic resonance imaging system |
| CN112816923A (en) * | 2020-12-29 | 2021-05-18 | 深圳市联影高端医疗装备创新研究院 | Ultrahigh field emission shimming coil structure |
| CN113552515A (en) * | 2021-06-29 | 2021-10-26 | 上海辰光医疗科技股份有限公司 | Dual-core imaging method for animal magnetic resonance imaging |
-
2004
- 2004-12-08 CN CN 200410089210 patent/CN1786730A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010083631A1 (en) * | 2009-01-23 | 2010-07-29 | 梅州康立高科技有限公司 | Magnetic therapy equipment for animal experiment |
| CN103357115B (en) * | 2012-04-09 | 2016-09-14 | 上海市计划生育科学研究所 | A kind of preparation and application of rodent models |
| CN103357115A (en) * | 2012-04-09 | 2013-10-23 | 上海市计划生育科学研究所 | Rodent-animal model manufacturing and application |
| CN103116146A (en) * | 2013-02-26 | 2013-05-22 | 江苏美时医疗技术有限公司 | Head radiofrequency coil for magnetic resonance imaging system |
| CN103116147A (en) * | 2013-02-26 | 2013-05-22 | 江苏美时医疗技术有限公司 | Knee radiofrequency coil for magnetic resonance imaging system |
| CN103116147B (en) * | 2013-02-26 | 2015-11-25 | 江苏美时医疗技术有限公司 | A kind of knee radiofrequency coil for magnetic resonance imaging system |
| CN103116146B (en) * | 2013-02-26 | 2015-11-25 | 江苏美时医疗技术有限公司 | A kind of head radiofrequency coil for magnetic resonance imaging system |
| CN105286864A (en) * | 2014-06-30 | 2016-02-03 | 中国科学院上海生命科学研究院 | Integrated coil, special for non-human primates, in magnetic resonance imaging system |
| CN106923827A (en) * | 2015-12-31 | 2017-07-07 | 中国科学院深圳先进技术研究院 | The coils special of the HIFU Treatment animal tumor guided by MRI |
| CN107884732A (en) * | 2016-09-30 | 2018-04-06 | 西门子(深圳)磁共振有限公司 | MR imaging apparatus, radio-frequency coil and its manufacture method |
| CN109696641A (en) * | 2018-12-29 | 2019-04-30 | 佛山瑞加图医疗科技有限公司 | Receiving coil apparatus and magnetic resonance imaging system |
| CN112816923A (en) * | 2020-12-29 | 2021-05-18 | 深圳市联影高端医疗装备创新研究院 | Ultrahigh field emission shimming coil structure |
| CN113552515A (en) * | 2021-06-29 | 2021-10-26 | 上海辰光医疗科技股份有限公司 | Dual-core imaging method for animal magnetic resonance imaging |
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Open date: 20060614 |