High-impedance coil device for lateral position mammary gland intervention

Abstract

The utility model discloses a high impedance coil device for lateral position mammary gland intervention, which comprises a coil support, two groups of orthogonal rectangular coil pairs are arranged on the coil support, each group of rectangular coil pair comprises two opposite coil channels, and the two groups of orthogonal rectangular coil pairs form a four-channel high impedance coil structure. Each coil channel is sequentially provided with an outer conductor layer, a dielectric layer and an inner conductor layer from outside to inside, the inner conductor layer and the outer conductor layer of each coil channel are partially overlapped in area, and the overlapped inner conductor layer and the outer conductor layer and the dielectric layer between the inner conductor layer and the outer conductor layer form a first capacitor; the inner conductor layer or the outer conductor layer is wound to form a first inductor; and each coil channel is connected with a detuning circuit and a matching circuit. According to the high-impedance coil device for lateral-position mammary gland intervention, the coil structure design is freer, the coupling problem does not need to be worried about, and the definition and accuracy of imaging signals are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of medical imaging, in particular to a high-impedance coil device for breast intervention in lateral position. Background Art

[0002] At present, all MRI-guided breast intervention surgeries are performed with the patient in the prone position. The patient is usually asked to lie prone on a special MRI breast intervention coil, exposing the mammary gland inside the coil, and the breast lesions of the patient are punctured from the open space on the side of the coil. During this process, the patient needs to remain still, and the hard breast coil will continue to cause physical discomfort to the patient. The prone breast MRI intervention coil has problems such as small open space, uncomfortable prone posture, and limited freedom of intervention operation. In response to this, we proposed a MRI-guided breast intervention device based on the lateral position, such as Figure 1 As shown. The interventional device is based on a side-lying support structure to ensure that the patient is in a more comfortable position during the operation. The splint moves from the side to fix the breast tissue for magnetic resonance imaging. The open coil structure allows interventional surgery to be performed in four directions. There is coupling interference between the coil channels of the traditional multi-channel coil during operation. The existing method to reduce coupling interference is mainly to improve the structure of the coil itself, but changing the structure of the coil itself will affect the performance of the coil itself, thereby affecting the clarity and accuracy of the imaging signal. Utility Model Content

[0003] In order to solve the technical problems existing in the background technology, the utility model proposes a high impedance coil device for breast intervention in the lateral position.

[0004] The utility model provides a high-impedance coil device for breast intervention in a lateral position, comprising a coil support, two groups of orthogonal rectangular coil pairs are arranged on the coil support, each group of rectangular coil pairs includes two opposite coil channels, the two groups of orthogonal rectangular coil pairs form a four-channel high-impedance coil structure, each coil channel is sequentially provided with an outer conductor layer, a dielectric layer, and an inner conductor layer from the outside to the inside, the inner conductor layer of each coil channel partially overlaps with the outer conductor layer, the overlapped inner conductor layer and the outer conductor layer together with the dielectric layer between the two form a first capacitor; the inner conductor layer or the outer conductor layer is wound to form a first inductor; each coil channel is connected to a detuning circuit and a matching circuit, the first capacitor and the first inductor of the same coil channel are connected to the capacitor C f2 and capacitor C f3 The tuning circuit is composed of capacitor C f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f2 One end of the capacitor is the first terminal, and the capacitor C f2 The other end is the second terminal, capacitor C f3The other end of the second terminal is a third terminal, and a matching circuit is connected in parallel between the second terminal and the third terminal.

[0005] Preferably, the detuning circuit is specifically a passive detuning circuit, which is connected in parallel with the first capacitor, and the passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end is electrically connected.

[0006] Preferably, the detuning circuit is specifically an active detuning circuit, an active detuning circuit is connected in parallel between the first endpoint and the second endpoint, the active detuning circuit comprises an inductor L and a diode D3, a cathode of the diode D3 is electrically connected to one end of the inductor L, and a cathode of the diode D3.

[0007] Preferably, the detuning circuit specifically includes a passive detuning circuit and an active detuning circuit, the passive detuning circuit is connected in parallel with the first capacitor, and the passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end of the inductor is electrically connected to the first end and the second end, an active detuning circuit is connected in parallel between the first end and the second end, the active detuning circuit includes an inductor L and a diode D3, the cathode of the diode D3 is electrically connected to one end of the inductor L, and the cathode of the diode D3.

[0008] Preferably, the matching circuit includes a variable capacitor C f4 , variable capacitor C m , variable capacitor C f4 One end of the variable capacitor C m One end of the variable capacitor C is electrically connected to m The other end of the variable capacitor C is electrically connected to the third end. f4 The other end is electrically connected to the second end.

[0009] Preferably, one end of the first capacitor is electrically connected to one end of the first inductor, and the other end of the first capacitor is electrically connected to the capacitor C f2 One end of the capacitor C is electrically connected to f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f3 The other end of is electrically connected to the other end of the first inductor.

[0010] Preferably, the two opposing coil channels are spaced more than 50 mm apart.

[0011] In the utility model, the high impedance coil device for breast intervention in the lateral position is proposed. In the stage of receiving magnetic resonance signals, the magnetic field changes in the induction area are converted into electrical signals through a tuning circuit, and the signals are transmitted to the post-stage preamplifier for processing through a matching circuit with maximum efficiency and narrowband transmission. The detuning circuit includes active detuning and passive detuning, and only works in the stage of magnetic resonance signal excitation. When the magnetic resonance transmitting coil is working, a high-power signal is coupled to the receiving coil, breaking down the "back-to-back" diode pair of the passive detuning, and the capacitor C f1 The coil frequency is offset and the target frequency signal is not received. Active detuning means that a DC signal is given to the coil connection end, turning on the diode D3, the inductor L and the capacitor C f2 Parallel resonance forms a short circuit, and the coil circuit is disconnected and does not work. The four-channel high-impedance coil is used as a lateral breast intervention coil. The simple coil has a simple and uniform distribution of the radio frequency magnetic field, is easy to make, has a high degree of openness, and is convenient for multi-directional interventional surgery operations. The coupling interference between the coil channels is reduced, making the coil structure design more free without worrying about coupling problems, and ensuring the clarity and accuracy of the imaging signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a working schematic diagram of the existing magnetic resonance-guided breast intervention device based on the lateral position proposed by the utility model;

[0013] Figure 2 This is a schematic diagram of the structure of a lateral-lying breast intervention coil of a high-impedance coil device for lateral-lying breast intervention proposed by the utility model;

[0014] Figure 3 This is a schematic diagram of the high impedance coil structure of a high impedance coil device for breast intervention in lateral position proposed by the utility model;

[0015] Figure 4 A schematic diagram of the high impedance coil circuit structure of a high impedance coil device for breast intervention in the lateral position proposed by the utility model Figure 1 ;

[0016] Figure 5 A schematic diagram of the high impedance coil circuit structure of a high impedance coil device for breast intervention in the lateral position proposed by the utility model Figure 2 ;

[0017] Figure 6 A schematic diagram of the high impedance coil circuit structure of a high impedance coil device for breast intervention in the lateral position proposed by the utility model Figure 3 ;

[0018] Figure 7 This is a schematic diagram of the relationship between reflection parameters and transmission parameters of a high-impedance coil device for breast intervention in lateral position proposed by the utility model when two rectangular high-impedance coils are 50 mm apart. DETAILED DESCRIPTION

[0019] Reference Figure 1-5 The utility model proposes a high-impedance coil device for lateral breast intervention, comprising a coil support, on which two groups of orthogonal rectangular coil pairs are arranged, each group of rectangular coil pairs includes two opposite coil channels, and the two groups of orthogonal rectangular coil pairs form a four-channel high-impedance coil structure, each coil channel is sequentially provided with an outer conductor layer, a dielectric layer, and an inner conductor layer from the outside to the inside, the inner conductor layer of each coil channel partially overlaps with the outer conductor layer, and the overlapping inner conductor layer and outer conductor layer together with the dielectric layer between the two form a first capacitor; the inner conductor layer or the outer conductor layer is wound to form a first inductor; each coil channel is connected to a detuning circuit and a matching circuit, and the first capacitor and the first inductor of the same coil channel are connected to the capacitor C f2 and capacitor C f3 The tuning circuit is composed of capacitor C f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f2 One end of the capacitor is the first terminal, and the capacitor C f2 The other end is the second terminal, capacitor C f3 The other end of the second terminal is a third terminal, and a matching circuit is connected in parallel between the second terminal and the third terminal.

[0020] In this embodiment, if Figure 2 As shown, there are four coil channels in total for the two rectangular coil pairs. Coil 1 (Coil1) is close to the human chest wall, through which the breast tissue enters; Coil 2 (Coil2) corresponds to 1. Considering the morphological changes of the squeezed tissue, the two channels are spaced about 80-100mm apart. The direction of the main magnetic field is along the head and feet B0. The radio frequency magnetic field (B1) generated by coils 1 and 2 is perpendicular to the coil plane and perpendicular to the main magnetic field (B0). Similarly, coils 3 (Coil3) and coils 4 (Coil4) generate vertical radio frequency magnetic fields (B1) that are perpendicular to the main magnetic field (B0). The directions of the radio frequency magnetic fields of the two coil pairs (Coil1&Coil2; Coil3&Coil4) are perpendicular and orthogonal, and will not interfere with each other.

[0021] In this embodiment, if Figure 3 As shown in the figure, the coil channel is composed of an inner conductor layer, an outer conductor layer and a dielectric layer, and forms a loop. When the coil channel is working, the current flowing inside is limited to reduce coupling with other coils. Figure 7As shown, the S parameters between two rectangular high impedance coils when they are 50mm apart: S11 / 22 is the reflection parameter of coil1 / coil2, and S21 / S12 is the transmission parameter (the two are equivalent in a reciprocal circuit), which represents the coupling relationship between the two coils. When S21 / S12 is lower than -15dB, it is considered that the two coils do not interfere with each other. Here, its maximum value is -16.2669dB, which means that the high impedance coils are 50mm apart without coupling interference. The complete coil circuit structure schematic diagram is shown below: Figure 4 As shown in the figure, it mainly includes tuning circuit, matching circuit and detuning circuit. In this circuit structure, the tuning circuit is composed of the coaxial line coil body, the frequency modulation capacitor and the feeding end capacitor. The matching circuit is connected to the resonant circuit and output to the source end. The detuning circuit includes active detuning and passive detuning: the active detuning is composed of a single diode and an inductor, and the passive detuning is composed of a pair of reverse diode pairs.

[0022] Specifically, Figure 6 As shown, the detuning circuit is specifically a passive detuning circuit, the passive detuning circuit is connected in parallel with the first capacitor, and the passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to the capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end is electrically connected.

[0023] Specifically, Figure 5 As shown, the detuning circuit is specifically an active detuning circuit. An active detuning circuit is connected in parallel between the first endpoint and the second endpoint. The active detuning circuit includes an inductor L and a diode D3. The cathode of the diode D3 is electrically connected to one end of the inductor L and the cathode of the diode D3.

[0024] Specifically, Figure 4 As shown, the detuning circuit specifically includes a passive detuning circuit and an active detuning circuit. The passive detuning circuit is connected in parallel with the first capacitor. The passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to the capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end of the inductor is electrically connected to the first end and the second end, an active detuning circuit is connected in parallel between the first end and the second end, the active detuning circuit includes an inductor L and a diode D3, the cathode of the diode D3 is electrically connected to one end of the inductor L, and the cathode of the diode D3.

[0025] Specifically, Figure 4 As shown, the matching circuit includes a variable capacitor C f4 , variable capacitor C m , variable capacitor C f4 One end of the variable capacitor C m One end of the variable capacitor C is electrically connected to m The other end of the variable capacitor C is electrically connected to the third end. f4 The other end is electrically connected to the second end.

[0026] Specifically, Figure 4 As shown, one end of the first capacitor is electrically connected to one end of the first inductor, and the other end of the first capacitor is electrically connected to the capacitor C f2 One end of the capacitor C is electrically connected to f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f3 The other end of is electrically connected to the other end of the first inductor.

[0027] Specifically, Figure 2 As shown, the two opposing coil channels are separated by more than 50 mm.

[0028] In this embodiment, the high impedance coil is different from the ordinary magnetic resonance coil in that it uses the inner and outer conductors of the coaxial line to establish a resonant circuit, and forms a flat capacitor through the overlapping area of ​​the inner and outer conductors instead of the traditional lumped capacitor to avoid the interference of the induced current flow to other coils in the working state. The impedance at both ends of the coil port is low, significantly lower than the intrinsic impedance of the coil body, so all coupling currents can be suppressed as much as possible through the subsequent preamplifier. However, since the flat plate capacitor formed by the inner and outer conductors is very small, it is difficult to meet the conditions for the magnetic resonance system frequency below 100MHz. For this reason, we propose to add a lumped capacitor in the outer conductor of the circuit to achieve a frequency reduction effect, while reducing the impact on the overall coil current distribution.

[0029] In this embodiment, the operating frequency of the tuning circuit should be consistent with the frequency of the magnetic resonance system. In the stage of receiving the magnetic resonance signal, the magnetic field change in the sensing area is converted into an electrical signal through the tuning circuit, and the signal is transmitted to the post-stage preamplifier for processing through the matching circuit with maximum efficiency and narrowband. The detuning circuit includes active detuning and passive detuning, and only works in the magnetic resonance signal excitation stage. When the magnetic resonance transmitting coil is working, the high-power signal is coupled to the receiving coil, breaking down the passively detuned "back-to-back" diode pair, and the capacitor C f1 The coil frequency is offset and the target frequency signal is not received. Active detuning means that a DC signal is given to the coil connection end, turning on the diode D3, the inductor L and the capacitor C f2Parallel resonance forms a circuit break, and the coil circuit is disconnected and does not work. Active detuning circuit and passive detuning circuit can be used at the same time, or only one of them can be used. Avoid interference with the transmitting coil and ensure that transmission and reception are independent of each other.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high impedance coil device for breast intervention in the lateral position, comprising a coil support, on which are disposed two groups of orthogonal rectangular coil pairs, each group of rectangular coil pairs comprising two opposite coil channels, and the two groups of orthogonal rectangular coil pairs forming a four-channel high impedance coil structure, characterized in that: Each coil channel is provided with an outer conductor layer, a dielectric layer, and an inner conductor layer in sequence from the outside to the inside. The inner conductor layer of each coil channel partially overlaps with the outer conductor layer, and the overlapping inner conductor layer and outer conductor layer together with the dielectric layer between the two form a first capacitor; the inner conductor layer or the outer conductor layer is wound to form a first inductor; each coil channel is connected to a detuning circuit and a matching circuit, and the first capacitor and the first inductor of the same coil channel are connected to the capacitor C f2 and capacitor C f3 The tuning circuit is composed of capacitor C f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f2 One end of the capacitor is the first terminal, and the capacitor C f2 The other end is the second terminal, capacitor C f3 The other end of the second terminal is a third terminal, and a matching circuit is connected in parallel between the second terminal and the third terminal.

2. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: The detuning circuit is specifically a passive detuning circuit, which is connected in parallel with the first capacitor. The passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end is electrically connected.

3. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: The detuning circuit is specifically an active detuning circuit. An active detuning circuit is connected in parallel between the first endpoint and the second endpoint. The active detuning circuit includes an inductor L and a diode D3. The cathode of the diode D3 is electrically connected to one end of the inductor L and the cathode of the diode D3.

4. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: The detuning circuit specifically includes a passive detuning circuit and an active detuning circuit. The passive detuning circuit is connected in parallel with the first capacitor. The passive detuning circuit includes a capacitor C f1 , diode D1, diode D2, the anode of diode D1 is electrically connected to the cathode of diode D2, the cathode of diode D1 is electrically connected to the anode of diode D2, the anode of diode D1 is electrically connected to capacitor C f1 The cathode of diode D1 is electrically connected to capacitor C f1 The other end of the inductor is electrically connected to the first end and the second end, an active detuning circuit is connected in parallel between the first end and the second end, the active detuning circuit includes an inductor L and a diode D3, the cathode of the diode D3 is electrically connected to one end of the inductor L, and the cathode of the diode D3.

5. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: The matching circuit includes a variable capacitor C f4 , variable capacitor C m , variable capacitor C f4 One end of the variable capacitor C m One end of the variable capacitor C is electrically connected to m The other end of the variable capacitor C is electrically connected to the third end. f4 The other end is electrically connected to the second end.

6. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: One end of the first capacitor is electrically connected to one end of the first inductor, and the other end of the first capacitor is electrically connected to the capacitor C f2 One end of the capacitor C is electrically connected to f2 The other end of the capacitor C f3 One end of the capacitor C is electrically connected to f3 The other end of is electrically connected to the other end of the first inductor.

7. The high impedance coil device for breast intervention in the lateral position according to claim 1, characterized in that: The two opposing coil channels are separated by more than 50 mm.

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