CN209842039U

CN209842039U - Gradient signal filter and gradient signal device for magnetic resonance imaging equipment

Info

Publication number: CN209842039U
Application number: CN201821510103.2U
Authority: CN
Inventors: 董微明; 鲍伟鸽; 贺增合
Original assignee: Siemens Shenzhen Magnetic Resonance Ltd
Current assignee: Siemens Shenzhen Magnetic Resonance Ltd
Priority date: 2018-09-14
Filing date: 2018-09-14
Publication date: 2019-12-24
Anticipated expiration: 2028-09-14

Abstract

The utility model provides a gradient signal filter and gradient signal device for magnetic resonance imaging equipment. The gradient signal filter has a forward path (11) for passing a Gradient Signal (GS) and a backward path (12) for returning the gradient signal, wherein a plurality of low-pass filters (111) connected IN series are provided IN the forward path (11), and a resonator (112) is provided IN one of the low-pass filters adjacent to an input terminal (IN1) of the gradient signal input to the forward path; a plurality of low-pass filters (121) connected in series are provided in the backward path (12), and a resonator (122) is provided in at least one of the low-pass filters (121) adjacent to the input end of the backward path to which the gradient signal is input, and the resonance frequency of the resonator is set to be the same as the radio frequency of the magnetic resonance imaging apparatus used for magnetic resonance imaging.

Description

Gradient signal filter and gradient signal device for magnetic resonance imaging equipment

Technical Field

The utility model relates to a gradient signal filter and gradient signal device for magnetic resonance imaging equipment.

Background

The gradient signal filter in the existing magnetic resonance imaging device is a traditional pi-type low-pass filter, for example, in the existing 9-stage gradient signal filter, in order to carry high voltage and high current, the cross-sectional area of a copper wire must be set to be relatively high, so as to ensure the stability and reliability of the product, and thus, the volume and weight of the gradient signal filter are relatively large. In addition, a relatively large installation space is required to secure heat dissipation of the filter. Therefore, the assembly and maintenance of the existing gradient signal filter require much time and labor.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides a simple structure, small light in weight's gradient signal filter and gradient signal device.

An embodiment of the present invention provides a gradient signal filter for a magnetic resonance imaging apparatus, having a forward path for transmitting a gradient signal and a backward path for returning the gradient signal, wherein a plurality of first low-pass filters connected IN series are provided IN the forward path 11, and a resonator is provided IN one of the first low-pass filters adjacent to an input terminal IN1 through which the gradient signal is input to the forward path; a plurality of second low-pass filters connected in series are provided in the backward path, and a resonator is provided in at least one of the second low-pass filters that is adjacent to an input end to which the gradient signal is input, and a resonance frequency of the resonator is set to be the same as a larmor frequency used by the magnetic resonance imaging apparatus for magnetic resonance imaging.

In the gradient signal filter, it is preferable that the first and second low-pass filters are configured such that one first capacitor is connected between each of both ends of one inductor and a ground terminal.

In the gradient signal filter, it is preferable that the resonator is configured such that a second capacitor is connected in parallel to the inductor between both ends of the inductor.

In the gradient signal filter, it is preferable that the resonator is configured such that a second capacitor and a resistor are connected in parallel to the inductor between both ends of the inductor, and the second capacitor is connected in series to the resistor.

In the above gradient signal filter, preferably the radio frequency is a larmor frequency related to a main magnetic field strength of the magnetic resonance imaging apparatus.

In the above gradient signal filter, the gradient signal filter is preferably a 5-stage filter.

Another embodiment of the present invention provides a gradient signal apparatus for a magnetic resonance system, which is provided with the above gradient signal filter between the gradient signal generating apparatus and the gradient coil.

According to the utility model discloses a gradient signal filter can just can filter and strain the signal of high frequency part with less volume for example only need 5 grades to the gradient signal to reduced gradient signal filter's volume and weight, be convenient for operate. In addition, in the gradient signal filter, the high-frequency attenuation performance, particularly the larmor frequency of the radio frequency signal which interferes with the gradient signal in magnetic resonance imaging, can be further improved by providing the resonator. Further, by providing a resistor in series with the second capacitor, the Q value of resonance can be reduced, and the bandwidth of the resonance frequency can be increased, thereby improving high-frequency attenuation performance.

Drawings

The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings, in which:

fig. 1 is a block diagram of a gradient signal filter for a magnetic resonance imaging apparatus according to a first embodiment.

Fig. 2 is a block diagram of a gradient signal filter for a magnetic resonance imaging apparatus according to a second embodiment.

Wherein the reference numbers are as follows:

10 gradient signal filter;

11 a forward path;

111 a low-pass filter;

1112. 1212 an inductor coil;

1113 a first capacitor;

1114 a second capacitor;

12 a backward path;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention is further described in detail by referring to the following embodiments.

Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numbers indicate identical or structurally similar elements but with identical functions throughout the several views.

"exemplary" means "serving as an example, instance, or illustration" herein, and any illustration, embodiment, or steps described as "exemplary" herein should not be construed as a preferred or advantageous alternative.

First embodiment

Fig. 1 shows a structural diagram of a gradient signal filter 10 for a magnetic resonance imaging apparatus according to an embodiment of the present invention, which is disposed between a gradient signal generating device and a gradient coil (not shown) of the magnetic resonance imaging apparatus. As shown in fig. 1, the gradient signal filter 10 comprises a forward path 11 for passing gradient signals GS to the gradient coil and a backward path 12 for returning gradient signals from the gradient coil. In the forward path 11, a plurality of low-pass filters 111 are connected in series, and in the present embodiment, two low-pass filters 111 are connected in series, and specifically, each low-pass filter 111 includes one inductor 1112, one first capacitor 1113 connected between one end of the inductor 1112 and the ground GND, and another first capacitor 1113 connected between the other end of the inductor 1112 and the ground GND. The forward path 11 of the 5-stage gradient signal filter is thus formed in the present exemplary embodiment by two inductors 1112 and three capacitors 1113. Further, IN the forward path 11, a resonator 112 is provided at a low-pass filter 111 which is adjacent to the input terminal IN1 where the gradient signal GS is input to the forward path 11. In the present embodiment, the resonator 112 is configured such that one second capacitor 1114 is connected in parallel to the inductor 1112 between both ends of the inductor 1112. In addition, the resonance frequency of the resonator 112 is set to be the same as the lamor frequency used by the magnetic resonance imaging apparatus for performing magnetic resonance imaging, for example, 63.6MHZ for a magnetic resonance imaging apparatus with a main magnetic field strength of 1.5T.

Similarly to the forward path 11 described above, a plurality of low-pass filters 121 connected in series are provided on the backward path 12, and in this embodiment, two low-pass filters 121 are connected in series, and specifically, each low-pass filter 121 includes one inductance coil 1212, and one first capacitor 1213 is connected between one end of the inductance coil 1212 and the ground GND, and another first capacitor 1213 is connected between the other end of the inductance coil 1212 and the ground GND. The backward path 12 of the 5-stage gradient signal filter is thus formed in the present exemplary embodiment by two inductors 1212 and three capacitors 1213. Further, IN the backward path 12, a resonator 122 is provided IN a low-pass filter 121 which is adjacent to the input terminal IN2 to which the gradient signal GS is input into the backward path 12. In the present embodiment, the resonator 122 is configured such that one second capacitor 1214 is connected in parallel with the inductance coil 1212 between both ends of the inductance coil 1212. In addition, the resonance frequency of the resonator 122 is also set to be the same as the larmor frequency used by the magnetic resonance imaging apparatus for performing magnetic resonance imaging.

Second embodiment

Fig. 2 shows a block diagram of a gradient signal filter 10' for a magnetic resonance imaging apparatus relating to a further embodiment of the present invention. In this embodiment, the structure is the same as that of the first embodiment except that the resonator composition provided in the forward path 11 and the backward path 12 is different from that of the first embodiment. Next, only the structure different from the first embodiment will be described.

As shown In fig. 2, In the forward path 11, a resonator 112' is provided In one of the low-pass filters 111 adjacent to the input terminal In1 to which the gradient signal GS is input. The resonator 112' includes a second capacitor 1114 and a resistor 1115, and the second capacitor 1114 is placed in series with the resistor 1115. As in the first embodiment described above, the resonance frequency of the resonator 112' is set to be the same as the larmor frequency used by the magnetic resonance imaging apparatus for performing magnetic resonance imaging.

Similarly, In the backward path 12, a resonator 122' is provided In one low-pass filter 121 adjacent to the input terminal In2 to which the gradient signal GS is input. The resonator 122 ' in the backward path 12 has the same structure as the resonator 112 ' in the forward path 11, the resonator 122 ' includes a second capacitor 1214 and a resistor 1215, and the second capacitor 1214 is disposed in series with the resistor 1215.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gradient signal filter for a magnetic resonance imaging apparatus, having a forward path for passing gradient signals and a backward path for returning the gradient signals, wherein,

a plurality of first low-pass filters connected in series are arranged in the forward path, and a first resonator is arranged in one of the first low-pass filters which is adjacent to the input end of the forward path to which the gradient signal is input;

and a plurality of second low-pass filters connected in series are arranged in the backward path, a second resonator is arranged in at least one second low-pass filter which is close to the input end of the backward path to which the gradient signal is input, and the resonant frequency of the first resonator and the resonant frequency of the second resonator are set to be the same as the radio frequency of the magnetic resonance imaging device when the magnetic resonance imaging device is used for magnetic resonance imaging.

2. The gradient signal filter for a magnetic resonance imaging apparatus according to claim 1,

the first and second low-pass filters are configured such that a first capacitor is connected between each of both ends of one of the inductors and a ground terminal.

3. The gradient signal filter for a magnetic resonance imaging apparatus according to claim 2,

the first resonator and the second resonator are configured such that a second capacitor is connected in parallel to the inductance coil between both ends of the inductance coil.

4. The gradient signal filter for a magnetic resonance imaging apparatus according to claim 2,

the first resonator and the second resonator are configured such that a second capacitor and a resistor are connected in parallel to the inductor between both ends of the inductor, and the second capacitor is connected in series to the resistor.

5. A gradient signal filter for a magnetic resonance imaging apparatus according to any one of claims 1 to 4,

the gradient signal filter is a 5-stage filter.

6. A gradient signal filter for a magnetic resonance imaging apparatus according to any one of claims 1 to 4,

the radio frequency is a larmor frequency related to a main magnetic field strength of the magnetic resonance imaging apparatus.

7. A gradient signal device for a magnetic resonance imaging apparatus,

a gradient signal filter as claimed in any one of claims 1 to 6 is provided between the gradient signal generating means and the gradient coil.