Double-tuned 23Na-31P annular array coil and design method

Abstract

The invention relates to a double-tuned 23Na-31P annular array coil and a design method, the double-tuned 23Na-31P annular array coil comprises a single coil, the single coil is provided with a double-tuned circuit and a double-matching circuit, and loop inductors are arranged between the single coil and the double-tuned circuit and between the single coil and the double-matching circuit; the single coil is of a birdcage coil structure and comprises an upper ring conductor, a lower ring conductor and a plurality of small coil units, the upper ends of the small coil units are connected with the upper ring conductor, the lower ends of the small coil units are connected with the lower ring conductor, the small coil units are connected through the upper ring conductor and the lower ring conductor, and the small coil units are arrayed circumferentially at equal intervals; and the small coil unit comprises an even number of groups of coils which are arranged in parallel. The single coil can be tuned to 23Na and 31P resonant frequencies, so that imaging data of two types of nuclei can be obtained in the same scanning, the imaging efficiency is improved, the scanning time is shortened, and the single coil is composed of a plurality of small coil units, has multiple channels and improves the signal receiving sensitivity and the signal-to-noise ratio.

Description

Technical Field

[0001] The present invention relates to the field of nuclear magnetic resonance imaging technology, and in particular to a dual-tuned 23 Na- 31 P ring array coil and design method. Background Art

[0002] Magnetic resonance imaging (MRI) is an important non-invasive technology that is widely used in medical diagnosis and research, and is of great significance in pediatric brain imaging. Childhood brain tumors are a more serious type of pediatric neurological disease, requiring accurate and rapid imaging for early diagnosis and treatment planning. So far, conventional MRI usually uses a single radionuclide (such as protons, 1 H) is currently one of the main means of diagnosing childhood brain tumors. It helps determine the size, location, shape, and spread of brain tumors by providing high-resolution anatomical images. 31 P can provide additional metabolic and biochemical information and has important potential in the diagnosis of childhood brain tumors. Revealing information about brain energy metabolism can provide detailed information about the location, size, morphology, and involvement of surrounding tissues of the tumor, which is helpful for early detection and quantitative assessment of tumors. 23 Na can measure the sodium ion concentration in tissues. Tumor cells usually have abnormal sodium ion metabolism, so it can help distinguish tumors from healthy tissues, which is important for early diagnosis.

[0003] Existing MRI equipment usually uses a single-frequency coil, or requires two independent coil systems for multi-core imaging, such as CN115047387A, "Dual-tuned radio frequency coil and design method of magnetic resonance system under ultra-high magnetic field", 10.11938 / cjmr20192737, 1 H / 31 This not only increases the complexity of the system, but also limits the flexibility and efficiency of imaging. In the diagnosis and monitoring of childhood brain tumors, long scans may cause discomfort and movement artifacts in children, affecting imaging quality and diagnostic accuracy. At the same time, current MRI technology faces many challenges in performing multi-core imaging simultaneously and efficiently, such as long scan times, low signal-to-noise ratio (SNR), and limited spatial resolution.

[0004] Therefore, a faster, more efficient and high-resolution multi-core head coil for children's brain scanning is urgently needed to solve the above problems. Summary of the invention

[0005] In order to solve the problems of long scanning time, low signal-to-noise ratio and limited spatial resolution of the existing single-frequency coil, the present invention proposes a dual-tuning 23 Na- 31P annular array coil and design method, a single coil can be tuned to 23 Na and 31 The resonance frequency of P makes it possible to obtain imaging data of two nuclei in the same scan, significantly improving imaging efficiency and reducing scanning time. The single coil is composed of multiple small coil units with multiple channels to improve the sensitivity of signal reception and signal-to-noise ratio.

[0006] In order to achieve the above-mentioned purpose, the present invention firstly proposes a dual tuning 23 Na- 31 The P annular array coil comprises a single coil, wherein the single coil is provided with a double tuning circuit and a double matching circuit, and a loop inductance is provided between the single coil and the double tuning circuit and the double matching circuit;

[0007] The single coil is a birdcage coil structure, comprising an upper ring conductor, a lower ring conductor and a plurality of small coil units, wherein the upper end of the small coil unit is connected to the upper ring conductor and the lower end is connected to the lower ring conductor, and the plurality of small coil units are connected through the upper ring conductor and the lower ring conductor, and the plurality of small coil units are arranged in a circumferentially equidistant array;

[0008] The small coil unit comprises an even number of coil groups, and the even number of coil groups are arranged in parallel.

[0009] Furthermore, the single coil is connected to an interface module, and the interface module includes a radio frequency divider, 31 P amplifier and 23 Na amplifier, the input end of the radio frequency divider is connected to the output end of the single coil, and the output end of the radio frequency divider is respectively connected to 31 P amplifier and 23 Na amplifier.

[0010] Setting the RF Divider Pair 23 Na and 31 P signal is processed by frequency division and then 23 Na amplifier and 31 The P amplifier performs amplification processing and optimizes the output signal.

[0011] Furthermore, the output end of the interface module is connected to a magnetic resonance system, and the magnetic resonance system includes 31 P receiving channel, 23 Na receiving channel and communication circuit,

[0012] Said 31 P receiving channel and 31 The output of the P amplifier is connected to 23 Na receiving channel and 23 The output end of the Na amplifier is connected, and the magnetic resonance system sends a detuning signal to the single coil through the communication circuit.

[0013] Furthermore, the number of the small coil units is 8, the small coil units include 4 groups of coils, and the 8 small coil units constitute a single coil with 32 channels.

[0014] Furthermore, the circumference of the single coil includes 60 cm, the diameter of the single coil includes 19 cm, the length of the single coil includes 25 cm, the interval between the eight small coil units includes 7.5 cm, and the diameter of the coil includes 5 cm.

[0015] The layout is optimized according to the anatomical characteristics of children's brains, and the size of the single coil, the interval between small coil units, and the diameter of the coil are determined. The sensitivity of signal reception and the signal-to-noise ratio efficiency are improved through the 32-channel single coil. This high-density design is particularly suitable for fine structural imaging of children's brains and can provide higher spatial resolution.

[0016] The second aspect of the present invention provides a dual tuning 23 Na- 31 The P ring array coil design method includes:

[0017] Step 1: Use HFSS 3D electromagnetic simulation software to perform simulation at 3T;

[0018] Step 2: Establish a single coil model, which includes an upper ring conductor, a lower ring conductor, a plurality of small coil units, a double tuning circuit, a double matching circuit and a loop inductor;

[0019] Step 3: Use the single coil model to resonate at 32.6MHz and 49.9MHz, and detect the reflection coefficient. If the reflection coefficient reaches -15dB, the single coil model meets the design requirements;

[0020] Step 4: Select a spherical range with a diameter of 18 cm in the center area of ​​the single-coil model and detect the uniformity of the magnetic field within the spherical range. If the average uniformity of the magnetic field is 15%, the single-coil model meets the design requirements.

[0021] Furthermore, the design parameters of the double-tuned circuit (2) in step 2 are shown in formula 1:

[0022] f LCtrap ∈(f 23Na , f 31P )(1);

[0023] Among them, f LCtrap is the resonant frequency of the LC line, f 23Na is the resonant frequency of Na, f 31P is the resonant frequency of P.

[0024] Furthermore, the design parameters of the dual matching circuit (3) in step 2 are shown in formula 2:

[0025] f LCtrap =f 31P (2).

[0026] Through the above technical solution, the beneficial effects of the present invention are:

[0027] 1. Dual tuning of the present invention 23 Na- 31 P ring array coil, adopts single coil double tuning design, single coil combined with double tuning circuit and double matching circuit can be tuned to 23 Na and 31 The resonance frequency of P is increased, the coupling effect is reduced, and imaging data of two nuclei can be obtained in the same scan. This design will significantly improve imaging efficiency and reduce scanning time.

[0028] 2. The single coil has a birdcage coil structure, which includes multiple small coil units, which are composed of an even array of coils. Therefore, the single coil has multiple channels to improve the sensitivity of signal reception and the signal-to-noise ratio efficiency. This high-density design is particularly suitable for fine structural imaging of children's brains and can provide higher spatial resolution.

[0029] 3. The multi-channel design of a single coil allows the use of parallel imaging techniques (such as SENSE), which significantly speeds up the imaging process. This not only shortens the scan time and improves patient comfort, but also reduces the impact of motion artifacts.

[0030] 4. Multiple small coil unit arrays can be optimally arranged according to the anatomical characteristics of the child's brain to ensure maximum coverage and reception uniformity. 23 Na and 31 The imaging data of P provides more comprehensive physiological and pathological information, which helps to make more accurate diagnosis and research. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A dual tuning 23 Na- 31 Circuit diagram of P ring array coil;

[0032] Figure 2 A dual tuning 23 Na- 31 One of the structural diagrams of the P ring array coil;

[0033] Figure 3 A dual tuning 23 Na- 31 The second structural diagram of the P ring array coil;

[0034] Figure 4 A dual tuning23 Na- 31 Double-tuned circuit diagram of P ring array coil;

[0035] Figure 5 A dual-tuning 23 Na- 31 Double matching circuit diagram of P ring array coil.

[0036] Figure numbers: 1 is a single coil, 2 is a double-tuned circuit, 3 is a double matching circuit, 4 is a loop inductor, 5 is an upper ring conductor, 6 is a lower ring conductor, 7 is a small coil unit, 8 is a coil, 9 is a radio frequency divider, 10 is 31 P amplifier, 11 is 23 Na amplifier. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0038] Example 1

[0039] like Figures 1 to 5 As shown, a dual-tuned 23 Na- 31 The P annular array coil comprises a single coil 1, wherein the single coil 1 is provided with a double tuning circuit 2 and a double matching circuit 3, and a loop inductor 4 is provided between the single coil 1 and the double tuning circuit 2 and the double matching circuit 3;

[0040] The single coil 1 is a birdcage coil structure, comprising an upper ring conductor 5, a lower ring conductor 6 and a plurality of small coil units 7, wherein the upper end of the small coil unit 7 is connected to the upper ring conductor 5 and the lower end is connected to the lower ring conductor 6, and the plurality of small coil units 7 are connected via the upper ring conductor 5 and the lower ring conductor 6, and the plurality of small coil units 7 are arranged in a circumferentially equidistant array;

[0041] The small coil unit 7 includes an even number of coil groups 8 , and the even number of coil groups 8 are arranged in parallel.

[0042] like Figure 1 As shown, the single coil 1 is connected to an interface module, and the interface module includes a radio frequency divider 9, 31 P amplifier 10 and 23 Na amplifier 11, the input end of the RF divider 9 is connected to the output end of the single coil 1, and the output end of the RF divider 9 is respectively connected to 31 P amplifier 10 and 23 Na amplifier 11.

[0043] The output end of the interface module is connected to a magnetic resonance system, and the magnetic resonance system includes 31 P receiving channel, 23 Na receiving channel and communication circuit,

[0044] Said 31 P receiving channel and 31 The output terminal of the P amplifier 10 is connected to 23 Na receiving channel and 23 The output end of the Na amplifier 11 is connected, and the magnetic resonance system sends a detuning signal to the single coil 1 through the communication circuit.

[0045] like Figure 2 and 3 As shown, the number of the small coil units 7 is 8, and the small coil units 7 include 4 groups of coils 8, and the 8 small coil units 7 constitute a single coil 1 with 32 channels.

[0046] The circumference of the single coil 1 is 60 cm, the diameter of the single coil 1 is 19 cm, the length of the single coil 1 is 25 cm, the interval between the eight small coil units 7 is 7.5 cm, and the diameter of the coil 8 is 5 cm.

[0047] Example 2

[0048] A dual tuning based on Example 1 23 Na- 31 The P ring array coil design method includes:

[0049] Step 1: Use HFSS 3D electromagnetic simulation software High Frequency Structure Simulator, Ans oft to perform simulation at 3T;

[0050] Step 2: Establish a single coil model, which includes an upper ring conductor 5, a lower ring conductor 6, a plurality of small coil units 7, a double tuning circuit 2, a double matching circuit 3 and a loop inductor 4;

[0051] Step 3: Use the single coil model to resonate at 32.6MHz and 49.9MHz, and detect the reflection coefficient. If the reflection coefficient reaches -15dB, the single coil model meets the design requirements;

[0052] Step 4: Select a spherical range with a diameter of 18 cm in the center area of ​​the single-coil model and detect the uniformity of the magnetic field within the spherical range. If the average uniformity of the magnetic field is 15%, the single-coil model meets the design requirements.

[0053] The design parameters of the double-tuned circuit (2) described in step 2 are shown in formula 1:

[0054] f LCtrap ∈(f 33Na , f 31P )(1);

[0055] Among them, f LCtrapis the resonant frequency of the LC line, f 23Na is the resonant frequency of Na, f 31P is the resonant frequency of P.

[0056] The design parameters of the dual matching circuit (3) described in step 2 are shown in formula 2:

[0057] f LCtrap =f 31P (2).

[0058] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A dual tuning 23 Na- 31 P ring array coil, characterized in that, The invention comprises a single coil (1), wherein the single coil (1) is provided with a double tuning circuit (2) and a double matching circuit (3), and a loop inductance (4) is provided between the single coil (1) and the double tuning circuit (2) and the double matching circuit (3); The single coil (1) is in a birdcage coil structure. The single coil (1) comprises an upper ring conductor (5), a lower ring conductor (6) and a plurality of small coil units (7). The upper end of the small coil unit (7) is connected to the upper ring conductor (5) and the lower end is connected to the lower ring conductor (6). The plurality of small coil units (7) are connected via the upper ring conductor (5) and the lower ring conductor (6). The plurality of small coil units (7) are arranged in a circumferentially equidistant array. The small coil unit (7) comprises an even number of coil groups (8), and the even number of coil groups (8) are arranged in parallel.

2. A dual tuning method according to claim 1 23 Na- 31 P ring array coil, characterized in that, The single coil (1) is connected to an interface module, and the interface module comprises a radio frequency divider (9), 31 P amplifier (10) and 23 Na amplifier (11), the input end of the radio frequency divider (9) is connected to the output end of the single coil (1), and the output end of the radio frequency divider (9) is respectively connected to 31 P amplifier (10) and 23 Na amplifier (11).

3. A dual tuning method according to claim 2 23 Na- 31 P ring array coil, characterized in that, The output end of the interface module is connected to a magnetic resonance system, and the magnetic resonance system includes 31 P receiving channel, 23 Na receiving channel and communication circuit, Said 31 P receiving channel and 31 The output terminal of the P amplifier (10) is connected to 23 Na receiving channel and 23 The output end of the Na amplifier (11) is connected, and the magnetic resonance system sends a detuning signal to the single coil (1) through the communication circuit.

4. A dual tuning method according to claim 1 23 Na- 31 P ring array coil, characterized in that, The number of the small coil units (7) is 8, the small coil units (7) include 4 groups of coils (8), and the 8 small coil units (7) constitute a single coil (1) with 32 channels.

5. A dual tuning method according to claim 4 23 Na- 31 P ring array coil, characterized in that, The circumference of the single coil (1) includes 60 cm, the diameter of the single coil (1) includes 19 cm, the length of the single coil (1) includes 25 cm, the interval between the eight small coil units (7) includes 7.5 cm, and the diameter of the coil (8) includes 5 cm.

6. A dual tuning device according to any one of claims 1 to 5 23 Na- 31 A Dual Tuning Method for P Ring Array Coil 23 Na- 31 The P ring array coil design method is characterized by: include: Step 1: Use HFSS 3D electromagnetic simulation software (High Frequency Structure Simulator, An soft) to perform simulation at 3T; Step 2: Establish a single coil model, which includes an upper ring conductor (5), a lower ring conductor (6), a plurality of small coil units (7), a double tuning circuit (2), a double matching circuit (3) and a loop inductor (4); Step 3: Use the single coil model to resonate at 32.6MHz and 49.9MHz, and detect the reflection coefficient. If the reflection coefficient reaches -15dB, the single coil model meets the design requirements; Step 4: Select a spherical range with a diameter of 18 cm in the center area of ​​the single-coil model and detect the uniformity of the magnetic field within the spherical range. If the average uniformity of the magnetic field is 15%, the single-coil model meets the design requirements.

7. A dual tuning method according to claim 6 23 Na- 31 The P ring array coil design method is characterized by: The design parameters of the double-tuned circuit (2) described in step 2 are shown in formula 1: f LCtrap ∈(f 23Na ,f 31P )(1); Among them, f LCtrap is the resonant frequency of the LC line, f 23Na is the resonant frequency of Na, f 31P is the resonant frequency of P.

8. A dual tuning method according to claim 6 23 Na- 31 The P ring array coil design method is characterized by: The design parameters of the dual matching circuit (3) described in step 2 are shown in formula 2: f LCtrap =f 31P (2)。

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