WO2016143943A1

WO2016143943A1 - Magnetic resonance susceptibility difference compensation filter and method for compensating for magnetic susceptibility difference using same

Info

Publication number: WO2016143943A1
Application number: PCT/KR2015/004323
Authority: WO
Inventors: 서대건; 이정현; 최관우; 이호범
Original assignee: 재단법인 아산사회복지재단
Priority date: 2015-03-12
Filing date: 2015-04-29
Publication date: 2016-09-15

Abstract

The present invention relates to a magnetic resonance susceptibility difference compensation filter and a method for compensating for a magnetic susceptibility difference using the same. When a silicone pad having a silicone base with an added anti-curing agent is applied to a thyroid diffusion-weighted imaging test on a subject of invention, the improvement in the magnetic susceptibility difference and the optimal thickness at the time of the improvement were investigated through the changes in the distortion and error rate. As a result, with respect to the error rates in left and right lobes of the thyroid of the subject of invention before and after the application of the silicone pad, the error rates in both of the left and right lobes were smaller after the application of the silicone pad rather than before the application of the silicone pad, and with respect to the optimal thicknesses of the left and right lobes of the thyroid according to the thickness change of the silicone pad, the one-way analysis of variance results showed that the thickness of the silicone pad was not statistically significant in either of the left or right lobes when 2 cm or greater, and thus it can be seen that the optimal thickness is 2 cm. In conclusion, as shown in the present invention, the compensation of the curve portion of the human body, which is in contact with air, using the silicone pad can reduce the magnetic susceptibility difference between the tissue and the air without affecting the contrast of the magnetic resonance signal, thereby obtaining images having high diagnostic values and reduced image distortion at the time of thyroid diffusion-weighted imaging.

Description

Magnetic resonance susceptibility difference compensation filter and magnetic susceptibility difference compensation method using the same

The present invention relates to a magnetic resonance susceptibility difference compensation filter and a method for compensating the susceptibility difference using the same. In detail, it is very important to maintain uniformity in the MR image, but the higher the magnetic field intensity, the lower the anatomical density of hydrogen in the human body. In order to improve the low uniformity of the image at the site, a silicon resin component synthesized with a silicon material similar to human tissue density and a weak signal or a silicone pad with a curing agent added to the silicon resin component can be changed in shape. Magnetic resonance susceptibility difference compensation filter and a susceptibility difference compensation method using the same.

Imaging methods for diagnosing thyroid disease, including thyroid cancer, include ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI).

Most of the thyroid disease, including the test method is performed by using a simple ultrasound, but the ultrasound is difficult to distinguish between benign and malignant lesions, the spatial resolution is poor, and lymph node metastasis There is difficulty in diagnosis. Computed tomography scans have better spatial resolution and easier calcification detection than ultrasound scans, but they also have difficulty in determining whether they have metastases due to low contrast and invasive tests using radiation. On the other hand, magnetic resonance imaging has excellent contrast and excellent spatial resolution, so it is possible to obtain useful information to determine staging of thyroid disease and to determine lymph node metastasis. have.

Thyroid examination using magnetic resonance imaging includes conventional T1 and T2 weighted image (WI) tests using spin echo (SE) and diffuse emphasis using echo planar imaging (EPI) pulse trains. There is a diffusion weighted imaging (DWI) test. T1 and T2 weighted images provide accurate morphological characteristics such as the shape of discontinuous capsules with low signal intensity around the tumor, irregular signals, and irregular shapes, but do not assess the functional status of the thyroid gland, and differentiate between benign and malignant lesions. There is a limit to. In contrast, diffusion-enhanced images can be evaluated functionally, and are useful for distinguishing benign from malignant lesions using apparent diffusion coefficient (ADC) images according to differences in diffusion coefficient values.

Diffusion-weighted images, however, are highly sensitive pulse trains for artifacts, and present various problems such as geometric distortion due to the inhomogeneity of the main magnetic field, loss due to dephase, and low resolution due to T2 * attenuation. The biggest problem is the geometric distortion caused by the nonuniformity of the main magnetic field. The main reason for the nonuniformity of the magnetic field in space is the non-uniformity of the main magnetic field itself and the difference in magnetization, that is, the susceptibility between the image target tissues. In particular, in the case of heterogeneous tissue composition, there are many susceptible artifacts of warpage due to the difference in susceptibility. In the head and neck area, the teeth and bones are in contact with the air, so the warpage of the image is more severe. It is located adjacent to the air, and the larynx and trachea are located around it, so the phase difference of the spindle due to the difference in susceptibility increases further, which causes a lot of strong image distortion.

Distortion of the image distorts the relationship between shape and surrounding position, making it difficult to accurately evaluate the function, thereby disrupting diagnosis and treatment. In spite of these problems, most hospitals are conducting tests without fundamental improvement, and they are invented only for equal fat elimination due to the difference in susceptibility between thin and complex parts such as feet and hands. For example, there is no current model or the invention related to the distortion improvement of the structure containing the air.

On the other hand, the strength of the main magnetic field and the effect of susceptibility on the magnetic resonance images are linearly proportional. In other words, as the intensity of the magnetic field increases, the effect by the susceptibility increases, and the signal at the interface between tissues decreases rapidly. In particular, high-magnetism equipment, which is highly preferred in recent years due to high signal-to-noise ratio, has become a big problem when image of thyroid gland, etc., in which several microstructures are complex, shows distortion of image due to different susceptibility than other parts. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object thereof is to solve the fundamental problem while compensating for a part of a curved human part in contact with air by using a material that does not affect the contrast of magnetic resonance signals. By reducing the difference in susceptibility between tissue and air, it provides a magnetic resonance susceptibility difference compensation filter and a method of compensating susceptibility difference using the same to obtain a high diagnostic value image by reducing distortion of the image when the human body diffuses the image. .

In order to achieve the above object, the magnetic resonance susceptibility difference compensation filter of the present invention includes a silicon pad made of a silicon base of a silicon resin component, and the silicone pad is applied to a human body part, but at least in the external space of the human body. Filled in part to compensate for the difference in susceptibility between human tissue and the outside of the human body.

In addition, the silicone pad is preferably added to the silicone base of the silicon resin component to prevent the shape change is possible.

In addition, it is preferable that the silicon pad is capable of compressive deformation or close contact so as not to create a space between the applied human body parts.

In addition, it is preferable to further include a cover covering the surface of the silicon pad.

According to the magnetic resonance susceptibility difference compensation filter of the present invention, by compensating for the bent portion in contact with the air using a silicon pad can reduce the susceptibility difference between the tissue and air without affecting the contrast of the magnetic resonance signal, the thyroid gland Diffusion-enhanced imaging of the human body, such as the image distortion is reduced to obtain a high diagnostic value image can be obtained.

In addition, by applying a cover of disposable cotton material that does not cause allergies to the silicone pad in contact with the skin, there is an effect that can reduce the burden on the patient to be in contact with the silicone pad for a long time during the test.

In addition, since the shape of the silicone pad can be freely changed, there is an effect that can be custom made and used in advance to be in close contact with each part of the body of the patient.

1 is a flowchart for solving the problem for the present invention.

Figure 2 is an exemplary view of a silicon pad according to the present invention (a) plane (b) front

3 shows an example of application of a silicon pad for thyroid MR imaging

4 is an exemplary view showing silicon pads of various thicknesses

5 shows an imaging method (a) T2 (b) b0 (c) b800 (d) ADC

6 is a view showing an example of the shape of the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention;

7 is a diagram showing an example of using the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention to the forefoot portion

8 is a diagram showing the use of the silicone pad of the magnetic resonance susceptibility difference compensation filter according to the present invention applied to the knee

9 to 12 are examples of the use of the silicone pad of the magnetic resonance susceptibility difference compensation filter according to the present invention applied to the wrist, elbow, ankle and shoulder

13 and 14 are diagrams illustrating a pillow-type silicon pad and a use example thereof when the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention is applied to the neck area;

Hereinafter, a preferred embodiment of a magnetic resonance susceptibility difference compensation filter according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only this embodiment to make the disclosure of the present invention complete and to those skilled in the art to fully understand the scope of the invention It is provided to inform you.

Prior to the full description of the present invention, first, the present invention will be described with reference to the flow chart of Figure 1 from the selection of materials to scientific experiments and the results thereof.

As shown in FIG. 1, a study for the present invention is classified into eight motion frames, and the detailed motions of each classified frame are as follows (wherein, corresponding drawings for each detailed motion are described in detail for each frame). Quoted as is).

1.자화율 차이를 측정할 수 있는 팬텀 제작1.Create a phantom that can measure the difference in susceptibility

In order to maximize the susceptibility effect based on the parameter values shown in Table 1, a phantom is produced to measure the susceptibility difference.

Table 1

Self-made phantom specifications

Cylinder	Radius	Height	Floor dimension	Side dimensions	volume
inside	50 mm	100 mm	78.50㎠	314.0㎠	785.0 ml
Out	20 mm	100 mm	12.56㎠	125.6㎠	125.6 ml

The self-made phantom has a bottom surface that can be filled to form a material in the form of a double cylindrical cylinder in which one side of the inner rectangle of 50 × 00 mm2 and the outer rectangle of 70 × 100 mm2 is used as the rotation axis. It has an inner cylinder and an outer cylinder.

2.자화율 차이를 줄일 수 있는 물질 실험2. Experiment with substances that can reduce the susceptibility difference

The experiment that selected the most effective material to reduce the difference of susceptibility between tissue and air was conducted without filling the outer cylinder surrounding the agarose solute to obtain the reference image such as the thyroid. T2 mapping, T2 * mapping, and T1 mapping images are acquired, and the same image is obtained by filling each study material in an external cylinder. The imaging technique used is spin echo technique for T2 mapped image, fast low angle shot (FLASH) technique for T2 * mapped image, and inversion recovery (IR) fast spin echo (TSE) for T1 mapped image. ) Technique was used.

Since R2 value cannot be measured directly in the acquired image, R2 'value post-processed image is generated using Matlab (Ver.7.10, Mathworks, USA) program.

Looking at this, the T2 'post-processing image, the T2 mapping image and T2 * mapping image

And

The R2 'post-processing image, which represents the susceptibility difference due to external influences, is obtained by reversing the values of the generated T2' post-processing image, T2 mapping image, and T2 * mapping image.

,

,

,

Create via

The R2 post-processed image generated as described above was measured using Image J to measure the signal intensity according to the change of the cross-sectional position of each image at the same location within the preset region of interest of the same size, and to compare and evaluate the difference in susceptibility.

3. 이상적인 물질의 조건을 고려하여 물질 선정3. Material selection considering the ideal material conditions

Based on the results of phantom fabrication and experiments (1 and 2), the susceptibility between air among the most effective materials that can reduce the difference between susceptibility between tissue and air among the materials that give a weak signal in the range that does not affect the volumetric volume. The present invention proceeds using silicon in the determination that silicon is the best in consideration of processability, ease of use, and reusability in selecting a material having the greatest effect to reduce the difference.

4. 선정된 물질 가공4. Processing selected materials

The silicon used in the present invention is a silicon resin component synthesized from a silicon raw material that produces a weak signal similar to the human tissue density, and is made of various materials based on silicon so that it can be reused many times through shape change. At room temperature, a curing agent is added to the base, and the main component, silicone base, is a mixture of polydimethylsiloxane, silica and silicone oil in a silicone polymer, and the curing agent is a mixture of methyl vinyl silicone gum and silicone oil. / Cm 3. The hardening | curing agent containing the said silicon base which consists of the silicon component which synthesize | combined the silicon raw material, methyl vinyl silicone gum, etc. is mixed and used by volume ratio of 3: 1-4: 1.

5. 갑상선 확산강조 영상 검사에 적용5. Applied to thyroid diffuse emphasis imaging

The method of the present invention for improving the susceptibility difference using silicon is located directly below the skin, adjacent to the air, and the larynx and trachea are located in the periphery of the thyroid gland, which causes a lot of warpage. After fabricating the silicon pads with a rectangle of 2 cm and a thickness of 2 cm, during the thyroid examination, before and after the application of the silicon pads, diffusion-weighted images and T2-weighted images were obtained, and the distortion and error rate of the diffuse-weighted images based on the T2-weighted images. Was compared (Fig. 2).

The amount of silicone used was 200 g, and the silicone pad was applied to completely compensate for the curved part of the neck when the silicone pad was applied, so that a part of the external space such as the neck was filled to fill the tissue of the neck and the body of the neck. In order to compensate for the external susceptibility difference, the curved part between the chest and the jaw was leveled with silicon compensation (FIG. 3).

Based on the above results, the optimum thickness of silicon was investigated to improve the susceptibility difference. According to the method of the present invention, the thickness of the silicon pad is changed by only changing the thickness of 1cm to 5cm in 1cm intervals in a rectangle of 18.5cm length and 7cm width (Fig. 4). Diffusion-weighted images and T2-weighted images were acquired in the same manner as the method of the present invention for improving the susceptibility difference, and then the distortion and error rate change according to the thickness of the diffuse-weighted images based on the T2-weighted images were evaluated.

6. 자화율 차이의 개선 여부 확인6. Determine if the susceptibility difference is improved

The amount of silicon used was 100 g when the thickness of the pad was 1 cm, 200 g when the thickness was 2 cm, 300 g when the thickness was 3 cm, 400 g when the thickness was 4 cm, and 500 g when the thickness was 5 cm. The same as the method of the present invention for whether or not.

Image distortion is based on the left and right lobe areas of the thyroid gland of the T2-weighted image, which are relatively unaffected by magnetic field unevenness, respectively. B 0 (b-value 0) and b 800 (b-value 800) In the ADC image, the left and right lobe areas of the thyroid gland were measured and compared (FIG. 5).

The error rate due to distortion of the image is a known distortion calculation formula (

) And then compared and analyzed.

7. 개선 시 최적의 두께 측정7. Optimum thickness measurement when improving

The distortion of the left and right lobes of the thyroid gland with the thickness of the silicone compensator decreased as the thickness of the silicone compensator increased in both the left and right lobes.

8. 유용성 증명8. Proof of Usability

The conditions of the ideal material to which the present invention is directed are as follows.

First, it should have the same density as that of human tissue and react with human tissue in magnetic field and RF pulse during magnetic resonance test. Second, it should not affect the contrast of magnetic resonance imaging. Third, there should be no risk when applied to patients. Fourth, easy to apply to patients (convenience). Fifth, it should be easy to customize according to the patient (processability). Sixth, do not cause inconvenience to the patient. Seventh, the patient should be able to reuse after application (reusability). Eighth, it should be mechanically robust without impact or environment. Ninth, the condition that the price is low must be satisfied.

Hereinafter, a magnetic resonance susceptibility difference compensation filter and a susceptibility difference compensation method using the same will be described in detail with reference to FIGS. 2 to 14 based on the result of performing the flowchart of FIG. 1.

Experimental results on the selection of the most effective material that can reduce the susceptibility difference between the tissue and the air of the human body equivalent according to Figure 1, the R2 'value representing the difference in susceptibility due to external influence is graphite (125.78 ± 17.32), silicon Powder (100.01 ± 42.57), air (29.16 ± 23.99), flour (21.96 ± 19.07), silicone pad (19.77 ± 16.49), saline (18.99 ± 17.85), borax (17.35 ± 15.26), sulfur (17.31 ± 15.26).

The smaller value of R2 'means that the difference in susceptibility due to external influences is smaller. When the air is regarded as the same condition of thyroid, graphite and silicon powder show larger susceptibility difference than standard. Physiological saline, borax, sulfur, etc. have a smaller susceptibility difference than the reference value, meaning that the use of the above material can reduce the susceptibility difference between tissue and air.

As a result of Duncan's ex post analysis to find out which of the R2 'values did not coincide with the R2' values based on air, there was a difference between four groups with a significance level of 0.05. Except for groups 3 and 4, which contain graphite and silicon powders, which show greater susceptibility differences than air as reference materials, Group 1 shows the same susceptibility difference because sulfur, borax, saline, silicon pads, and flour are not significantly different in the group. As can be seen, Group 2 was found to have no difference in the group with air, which is the reference state of physiological saline, silicone pad, and flour.

The sections were divided into three sections (top (sections 1 to 7), middle (sections 8 to 13), and bottom (sections 14 to 20). As a result, all three sections were graphite, silicon powder, air, flour, and silicon pads. , Physiological saline, borax, and sulfur in the same order as the overall analysis. Duncan's ex post analysis was performed to determine which of the divided R2 'values did not match the air-based R2' values. There was a difference between the three groups in the middle and bottom. Looking at each of the subgroups, the difference in susceptibility between borax, sulfur, and silicon pads is smaller than that of air as a reference material when considering group 1 and group 2 in the upper part, and in the middle, the magnetic field is homogeneous and graphite and silicon powder It can be seen that all materials except the group have no significant difference, and in the lower case, the difference in susceptibility of borax, sulfur, silicon pad, and saline solution is smaller than that of air as a reference material. Therefore, when all three parts are considered, borax, sulfur, and silicon pads are useful because they have a smaller susceptibility difference than air as a reference material. The above results can also be seen in the Bland-Atman plot. Looking at the relationship between the reference material air and the materials for the present invention, all three parts have a negative value in the case of graphite and silicon powder, so that the susceptibility difference is higher than that of air. It can be seen that large, flour, silicon pads, saline, borax, sulfur, etc., the average value has a positive value can be seen to show less difference in susceptibility than air as a reference material. In addition, the flour, silicon pads, physiological saline, borax, sulfur, etc., except graphite and silicon powder, have a small standard deviation, and thus, even when the material is applied to overcome the difference in susceptibility, it can be seen that uniform performance is shown.

The T1 values of the most effective substances that can reduce the difference in susceptibility between tissue and air among human equivalents are shown in Table 2. As a result, there is a difference in the T1 value between the substances for the present invention, but it is not statistically significant, and thus there is no difference in the T1 value between the substances for the present invention. Therefore, it can be seen that any material used for the present invention does not change the intrinsic T1 value of the tissue due to the material.

TABLE 2

T1 relaxation time for various materials

matter	T1 (msec)	R1 (sec ^-1 )
Graphite powder	2689.78	0.37
Silicon powder	2676.64	0.37
air	2860.76	0.35
flour	2706.27	0.37
Silicone pad	2722.76	0.37
Physiological Saline Solution	2866.62	0.35
Borax Powder	2806.48	0.36
Sulfur powder	2806.51	0.36

Based on the above results, in order to select the most effective material that can reduce the susceptibility difference between the tissue and the air targeting borax, sulfur, and silicon pad having a smaller susceptibility difference than the reference material air, the ideal material to which the present invention is directed It was calculated on the Likert 5-point scale (1: very unsuitable, 2: unsuitable, 3: normal, 4: suitable, 5: very suitable) in consideration of the conditions of.

TABLE 3

Likert scale results for ideal materials

	(One)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	Total
Graphite powder	One	One	One	One	One	One	One	One	3	11
Silicon powder	One	One	One	One	One	One	One	One	3	11
flour	4	5	5	One	One	One	One	One	4	23
Silicone pad	5	3	5	4	5	4	4	4	3	37
Physiological Saline Solution	4	One	5	One	One	One	One	One	4	19
Borax Powder	5	5	One	One	One	One	One	One	3	19
Sulfur powder	5	5	One	One	One	One	One	One	3	19

(1) Respond with the same RF pulse with the body during MRI scanning.

(2) No effect on the MRI image signal.

(3) There is no harmful effect on the patient.

(4) It is easy to apply (convenience)

(5) easy to self-manufacture

(6) We do not inconvenience patient.

(7) Can be reused.

(8) Not affected by the surrounding environment.

(9) Cost effective.

As a result, the silicon pads were very high in all items, with 37 out of 45 (82.22%), and the silicone pad was selected as the most effective material to reduce the difference in susceptibility between tissue and air. Table 3).

According to the results of application of the imaging test of the silicon pad selected as the most ideal material according to the flow chart of FIG. 1, the distortion of the left and right lobes of the thyroid gland of the subject before and after the application of the silicon pad was determined after the application of the silicon pad in the left lobe (b0). : 184.58 ± 55.90, b800: 178.06 ± 56.29, ADC: 182.64 ± 54.37) compared with before application (b0: 154.49 ± 59.62, b800: 50.08 ± 59.36, ADC: 152.31 ± 59.13) Similarly to the left lobe, after application of the silicone pad (b0: 215.14 ± 61.13, b800: 212.99 ± 55.53, ADC: 214.86 ± 58.34) before application (b0: 173.01 ± 60.10, b800: 167.48 ± 60.96, ADC: 171.28 ± 63.44) The distortion of the image was less than that of (Table 4).

Table 4

Area measurements of the left and right thyroid gland with and without the application of silicone pads in comparison to image distortion (unit: mm 2)

division		I'm	after
Left lobe	T2	212.29 ± 60.97	207.13 ± 56.70
Left lobe	b0	154.49 ± 59.62	184.58 ± 55.90
Left lobe	b800	150.08 ± 59.36	178.06 ± 56.29
Left lobe	ADC	152.31 ± 59.13	182.64 ± 54.37
Right lobe	T2	248.51 ± 67.84	245.90 ± 62.56
Right lobe	b0	173.01 ± 60.10	215.14 ± 61.13
Right lobe	b800	167.48 ± 60.96	212.99 ± 55.53
Right lobe	ADC	171.28 ± 63.44	214.86 ± 58.34

The error rate of the left and right thyroid glands of the subjects before and after the application of the silicone pads was lower in the left and right lobes than in the silicone (10% range) compared with before (30%) (Table 5).

Table 5

Difference between left and right thyroid gland with and without silicone pads in%

division	I'm		after
Left lobe	b0	28.73 ± 14.24	12.67 ± 10.32
Left lobe	b800	31.01 ± 13.86	14.79 ± 10.63
Left lobe	ADC	29.70 ± 14.56	12.21 ± 9.17
Right lobe	b0	30.84 ± 13.55	12.87 ± 9.49
Right lobe	b800	33.39 ± 13.71	13.96 ± 7.64
Right lobe	ADC	31.74 ± 15.32	13.78 ± 8.40

Table 6

One-way ANOVA of both left and right thyroid gland with and without application of silicone pads

division		I'm
division		Sum of squares	Average Square	F	sig
Left lobe	Between groups	81270.00	27090.00	7.582	.000
Left lobe	In group	414463.94	3572.96
Left lobe	all	495733.94
Right lobe	Between groups	137082.37	45694.12	11.456	.000
Right lobe	In group	462681.94	3988.64
Right lobe	all	599764.31

TABLE 7

division		I'm
division		Sum of squares	Average Square	F	sig
Left lobe	Between groups	15151.68	5050.56	1.621	.188
Left lobe	In group	361481.75	3116.22
Left lobe	all	376633.43
Right lobe	Between groups	22507.32	7502.44	2.122	.101
Right lobe	In group	410046.65	3534.88
Right lobe	all	432553.97

The results of one-way ANOVA of the left and right thyroid gland according to before and after application of the silicone pad to reduce distortion are shown in Tables 6 and 7. If the silicone pad was not applied, both the left and right lobes of the thyroid gland were statistically significant (p <0.05), indicating that there was at least one significant measurement that did not match at least the area of the baseline T2-weighted image. When the silicon pad was applied, the left and right lobes were not statistically significant (p> 0.05), indicating that the area coincided with the T2-weighted image.

Duncan's post-mortem analysis was performed to find an image that did not match the T2-weighted image among the measured values. It can be seen that there is a difference in the area of the T2-weighted image and the diffusion-weighted image, which are the reference images, and when the silicon pad is applied, only one subgroup exists, so that the area of the T2-weighted and diffusion-weighted images is different. It can be seen that there is no (Table 8).

Table 8

Post-hoc comparison of both left and right thyroid gland with and without silicone pads

division		I'm		after
division		Subset for alpha = 0.05
division		One	2	One
Left lobe	b800	150.08		178.06
Left lobe	ADC	152.31		182.64
Left lobe	b0	154.49		184.58
Left lobe	T2		212.29	207.13
Left lobe	Sig.	0.790	1.000	0.067
Right lobe	b800	167.48		212.99
Right lobe	ADC	171.28		214.86
Right lobe	b0	173.01		215.14
Right lobe	T2		248.51	245.90
Right lobe	Sig.	0.752	1.000	0.051

As the thickness of the silicone pad was increased, the distortion of the left and right lobes of the subject's thyroid gland decreased as the thickness of the silicone pad increased (Table 9 and Table 10).

Table 9

Area measurements of both the left and right thyroid gland along with the various thicknesses of the silicone pad (unit: mm2)

division		Unapplied	1 cm	2 cm
Left lobe	T2	212.29 ± 60.97	211.12 ± 61.62	207.13 ± 56.70
	b0	154.49 ± 59.62	177.79 ± 61.78	184.58 ± 55.90
	b800	150.08 ± 59.36	172.86 ± 60.61	178.06 ± 56.29
	ADC	152.31 ± 59.13	177.79 ± 61.39	182.64 ± 54.37
Right lobe	T2	248.51 ± 67.84	248.66 ± 65.13	245.90 ± 62.56
	b0	173.01 ± 60.10	208.93 ± 66.11	215.14 ± 61.13
	b800	167.48 ± 60.96	200.50 ± 62.35	212.99 ± 55.53
	ADC	171.28 ± 63.44	207.94 ± 61.50	214.86 ± 58.34

Table 10

Area measurements of both thyroid glands on the left and right sides, with various thicknesses of silicon pads

division		3 cm	4 cm	5 cm
Left lobe	T2	208.81 ± 60.06	208.05 ± 56.49	207.59 ± 57.51
	b0	189.62 ± 60.73	191.86 ± 58.64	197.83 ± 60.29
	b800	184.14 ± 61.22	186.87 ± 59.31	190.59 ± 62.27
	ADC	188.49 ± 60.31	192.84 ± 56.93	198.32 ± 56.18
Right lobe	T2	248.53 ± 64.96	245.88 ± 61.58	246.12 ± 62.33
	b0	222.60 ± 69.86	229.34 ± 65.98	234.24 ± 70.77
	b800	216.36 ± 70.27	222.10 ± 66.84	226.09 ± 69.52
	ADC	222.76 ± 68.19	230.13 ± 63.14	236.39 ± 64.80

Table 11

Difference between left and right thyroid gland with thickness of silicon pad (unit:%)

division		Unapplied	1 cm	2 cm
Left lobe	b0	28.73 ± 14.24	16.54 ± 11.49	12.67 ± 10.32
	b800	31.01 ± 13.86	19.06 ± 11.73	14.79 ± 10.63
	ADC	29.70 ± 14.56	16.62 ± 11.15	12.21 ± 9.17
Right lobe	b0	30.84 ± 13.55	16.46 ± 12.31	12.87 ± 9.49
	b800	33.39 ± 13.71	19.77 ± 12.12	13.96 ± 7.64
	ADC	31.74 ± 15.32	16.72 ± 11.11	13.78 ± 8.40

Table 12

division		3 cm	4 cm	5 cm
Left lobe	b0	10.05 ± 9.58	9.25 ± 9.20	9.08 ± 7.42
	b800	12.91 ± 10.14	11.45 ± 9.91	10.45 ± 1 0.22
	ADC	11.07 ± 8.69	9.16 ± 8.82	7.40 ± 6.98
Right lobe	b0	11.67 ± 9.42	8.73 ± 8.55	8.48 ± 6.71
	b800	14.26 ± 10.59	11.01 ± 9.64	10.15 ± 9.33
	ADC	11.66 ± 9.68	8.72 ± 7.37	8.24 ± 6.17

The error rate of the left and right lobes of the thyroid gland of the subject according to the thickness change of the silicon pad decreased as the thickness of the silicon pad increased in both the left and right lobes (Tables 11 and 12).

As a result of one-way distribution analysis of the left and right thyroid gland according to the thickness change of the silicone pad, when the silicone pad was not applied, both the left and right lobes of the thyroid gland were significantly (p <0.05), and at least the area coincided with the reference T2-weighted image. One or more significant measurements are included, and the left lobe is not significant (p> 0.05) but the right lobe is significant (p <0.05) when the silicone pad is applied at 1 cm thickness. It can be seen that the value of exists in the right lobe. Since the thickness of the silicon pad was more than 2 cm, the left and right lobes were not statistically significant (p> 0.05). Duncan's post-mortem analysis was performed to determine the optimal thickness for the improvement of image distortion, and when the silicone pad was not applied and 1 cm was applied, both the left and right lobes of the thyroid had a subgroup of significance level of 0.05. There is a difference between the two groups and the area of the T2-weighted image, which is the reference image, is different. Can be.

The following describes the results of experiments by applying a silicone pad to the foot in addition to the thyroid part according to another embodiment of the present invention.

Fat saturation is often used as a clinical image to improve tissue contrast and lesion characteristics. However, the acquisition of uniform fat suppression is often challenged by the complex magnetic environment encountered during imaging of the clinical musculoskeletal, in particular hand and foot imaging.

Magnetic field heterogeneity induced by anatomical shapes and the presence of multiple tissue-tissue and tissue-air interfaces makes it difficult to compensate for with hardware magnetic field correction. Previous studies have reported several methods used to achieve uniform fat inhibition. Apparatuses for improving fat inhibition in MRI tests have been proposed, for example rice pads compared to perfluorocarbon liquid pads in knee MRI tests, as well as atta used in chemical-selective fat saturation during neck and head imaging Apparatuses containing attapulgite have been proposed.

To the best of our knowledge, no studies have been conducted using silicon pads during MRI foot imaging. In addition, silicone pads are more cost effective than instruments filled with commercial perfluorocarbon liquids or perfluoro-compounds. Therefore, it is an object of another embodiment of the present invention to evaluate the effectiveness of a silicone pad for uniform fat inhibition during a 3T MRI scan of the foot.

SNR and CNR were measured at four ROIs with an area of 10 mm 2. ROI 1 and 2 were selected from the toe flank bones and soft tissues with incomplete fat suppression, while ROI 3 and 4 were selected from the relatively basal bones and soft tissues with complete fat suppression. ROIs were as follows: (1) ROI on the first phalanx; (2) the ROI below the first phalanx; (3) ROI on the first metatarsals; And (4) ROI under the first metatarsal phalanx joint. SNR and CNR were calculated using the following equation: SNR = (lesion SI / background SD) × 100, CNR = | (lesion SI- surrounding tissue SI) / background noise SD│X100. The background signal was assumed to be zero, and ROI 3 and 4 were measured as the surrounding tissue for ROI 1 and 2.

At four point scales, three readers were given the overall quality of the image (4, very good; 3, good; 2, acceptable; 1, poor), homogeneity of the first phalanx (4, very good) for groups A and B Homogeneous; 3, homogeneous; 2, partially homogeneous; 1, heterogeneous; homogeneity of metatarsal bones (4, very good homogeneous; 3, homogeneous; 2, partially homogeneous; 1 , Heterogeneity). Average ratings from three radiographers were calculated in three categories.

The images obtained from group B improved the heterogeneity of the first phalanx (ROI 1) and the soft tissue below the first phalanx (ROI 2), while ROI 3 and 4 showed an improvement in the image heterogeneity compared to group A. Did not give.

In group A, all SNR and CNR values in ROI 1 and 2 were significantly higher than those obtained in group B, with no significant difference in ROI 3 and 4.

The qualitative score of the overall quality of fat inhibition in group B was significantly higher than that seen in group A (P <0.001). Homogeneity of the first phalanx in group B was also significantly higher than that in group A (P <0.001). On the other hand, the homogeneity of the metatarsals did not differ significantly in the two groups.

The results of another embodiment of the present invention suggest that silicone pads provide good fat inhibition for conventional SPIR imaging and are related to the ability to improve the uniformity of fat inhibition in 3T MRI. In the general definition, high SNR is expected as the result of the experiment. However, in another embodiment of the present invention, SNR meant the degree of residual fat signal as a result of incomplete fat saturation. In group B, fat inhibition was stronger due to the silicone pad, so less fat signal was observed than in group A.

This is why SNR has been significantly reduced in ROI 1 and 2 of Group B. Likewise, in a general definition, high CNRs are also expected, but in other embodiments of the present invention CNR meant the degree of heterogeneity between ROIs where fat inhibition was complete and incomplete. ROI 1 and 2 were chosen where fat inhibition was incomplete. ROI 3 and 4 were chosen where fat inhibition was complete. In group B, fat inhibition was stronger due to the silicone pad, so less fat signal was observed than in group A on ROI 1 and 2 phases. In the formula that gives the CNR, the molecule is the signal strength of the lesion minus the signal strength of the surrounding tissue. The signal intensity of the lesions was smaller as a result of better fat inhibition in group B. As a result, the CNRs were reduced in ROI 1 and 2.

In addition, silicone pads do not cause chemical reactions with other chemicals. It also does not contain toxic substances. It also does not cause allergic reactions. Therefore, it is not harmful to the human body. Silicone pads cannot be washed or cleaned, but the pads contain antifungal agents. This is proved by Korea Testing & Research Institute. The antimicrobial activity level (R) of the silicone pad was greater than 5 for the following three bacteria; Escherichia coli, Staphylococcus aureus, Salmonella. Antimicrobial activity levels (R) above 2 were considered effective.

Silicone pads have the advantage of rapid imaging with high magnetic field MRI scans and are useful for providing more active fat suppression, enabling high quality MRI scans with reduced susceptibility artifacts located near the surface of the foot. Another embodiment of the present invention has shown that the application of silicone pads can be an effective way to improve the homogeneity of fat inhibition in the foot.

In conclusion, the use of silicone pads can provide uniform fat inhibition in the 3T MRI of the foot and significantly improve the image both quantitatively and qualitatively.

As described above, in the description of the embodiment of the present invention, the compensation for the difference in magnetic resonance susceptibility between the thyroid gland and the foot, which is a part of the human body, has been described. Could be.

Accordingly, as described below, an embodiment in which the silicone pad of the magnetic resonance susceptibility difference compensation filter according to the present invention is applied to various parts of the human body will be described.

6 is a view showing an example of the shape of the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention.

As shown in Figure 6, the silicon pad 10 of the magnetic resonance susceptibility difference compensation filter according to the present invention can be freely deformed shape, so when applied to the bent portion, such as the neck, is in close contact with the front of the neck It is composed of two types of silicon pads 10a having a ∪ shape so as to be covered, and two silicon pads 10b having a straight shape so as to be covered in close contact with the back of the neck. That is, the silicon pad 10 is composed of a ∪-shaped silicon pad 10a and a straight silicon pad 10b separately applied to the front and back of the neck area. Here, the straight silicone pad 10b may be applied in close contact with the chest because it is in a straight form in addition to the neck. As described above, the silicone pad 10b may be freely deformed into a shape that fits the part of the human body, such as a neck area, and may be deformed when the silicon pad 10b is in close contact with the part of the human body. It is preferable to prevent this from occurring.

7 is a diagram showing an example of using the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention in the forefoot part.

As shown in FIG. 7, the front pad portion of the magnetic resonance susceptibility difference compensation filter according to the present invention is covered with the silicon pad 10. In this case, when the front portion of the foot is applied in a form that surrounds the front part of the foot and the silicon pads may affect the compensation of the susceptibility difference, the front of the foot by wrapping and tightening the silicone pad 10 so as not to create a gap between It is desirable to use a band 20 that can be in close contact with the part.

8 is a diagram showing an example of use when the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention is applied to a knee.

As shown in FIG. 8, when the silicon pad 10 of the magnetic resonance susceptibility difference compensation filter according to the present invention is to be applied to a bent portion such as the back of the knee, the pad 10 is disposed in an empty space behind the knee. It is configured in the form of an oblique inclined plate to fill the (), but the silicone pad 10 is inserted into the pedestal 30 to support the knee while supporting the knee in close contact with the silicone pad 10 behind the knee. It is desirable to be positioned.

8 to 12 are examples of the use of the silicone pad of the magnetic resonance susceptibility difference compensation filter according to the present invention applied to the wrist, elbow, ankle and shoulder.

As shown in Figures 8 to 12, the silicon pad 10 according to the present invention can be freely changed in shape, it can be used in the form of a protector wrapped in close contact with the wrist, elbow, ankle and shoulder.

13 and 14 are diagrams illustrating a pillow-type silicon pad and an example of using the silicon pad of the magnetic resonance susceptibility difference compensation filter according to the present invention.

As shown in Figure 13 and 14, when the silicone pad 10 of the magnetic resonance susceptibility difference compensation filter according to the present invention is applied to the back of the neck, it is possible to comfortably support the neck, unlike the above It can be configured in the form of a pillow. Thus, when configuring the silicone pad 10 in the form of a pillow to support the back and the back of the neck comfortably, to form a pillow form formed by connecting the protrusion 40 and the groove 50 on the supporting portion of the upper surface. desirable.

As described above, the silicone pad 10 used in various forms is in contact with the skin of the human body for about an hour, and thus may cause unnecessary skin troubles such as allergies. It is preferable to cover the cotton material. The cover can be reused several times by washing, and can also be used for disposable use by hygiene needs.

As described above with reference to the drawings illustrating a magnetic resonance susceptibility difference compensation filter and a susceptibility difference compensation method using the same, the present invention is not limited to the embodiments and drawings disclosed herein, Various modifications can be made by those skilled in the art within the scope of the technical idea of the present invention.

Compensating the curved portion in contact with the air using the silicon pad of the present invention can reduce the susceptibility difference between the tissue and the air without affecting the contrast of the magnetic resonance signal, during the inspection of the diffuse emphasis image of the human body, such as the thyroid gland It can be usefully used as a magnetic resonance susceptibility difference compensation filter that can obtain a high diagnostic value image with reduced distortion.

In addition, by applying the cover of disposable cotton material that does not cause allergy to the silicon pad that comes into contact with the skin, it can be usefully used as a magnetic resonance susceptibility difference compensation filter that can reduce the burden on patients who need to contact the silicon pad for a long time during the examination. Can be.

In addition, since the shape of the silicon pad can be freely changed, it can be usefully used as a magnetic resonance susceptibility difference compensation filter that can be custom made and used in a shape that closely adheres to each part of the patient's body.

Claims

It includes a silicon pad composed of a silicon base of the silicon resin component,

Magnetic resonance susceptibility difference compensation filter, characterized in that the silicone base is applied to the human body part, by filling at least a portion of the external space of the human body to compensate for the difference in susceptibility between human tissue and the outside of the human body.
The method of claim 1,

The silicone pad is a magnetic resonance susceptibility difference compensation filter, characterized in that the shape change is possible by adding a curing agent to the silicon base of the silicon resin component.
The method of claim 1,

The silicon pad is magnetic resonance susceptibility difference compensation filter, characterized in that the compression deformation or close contact so as not to create a space between the applied human body parts.
The method of claim 1,

The magnetic resonance susceptibility difference compensation filter further comprises a cover covering the surface of the silicon pad.
The method of claim 1,

Magnetic resonance susceptibility difference compensation filter, characterized in that the silicon pad is configured in the form of a gel (gel).
The method of claim 2,

Wherein said silicone base is a mixture of polydimethylsiloxane, silica and silicone oil added to a silicone polymer, and said hardening agent is a mixture of methyl vinyl silicone gum and silicone oil.
The method of claim 1,

The silicon pad may be configured of a pad-shaped pad covering the curved portion of the human body or a straight pad covering the flat portion of the human body, and the pad-shaped pad and the straight pad may be used alone or together. Resonance susceptibility difference compensation filter.
The method of claim 1,

The magnetic resonance susceptibility difference compensation filter further comprises a band for compensating the curvature of the human body and tightening the silicone pad covering the human body so as not to create an empty space between the human body and the silicone pad.
The method of claim 1,

The silicon pad is configured to fill the empty space by the bending of the human body, the magnetic resonance susceptibility difference compensation further comprises a pedestal for placing the silicon pad inside while supporting the application site of the human body filter.
The method of claim 1,

The silicon pad is magnetic resonance susceptibility difference compensation filter, characterized in that formed in the form of a guard that wraps around the application area of the human body.
The method of claim 1,

The silicone pad is magnetic resonance susceptibility difference compensation filter, characterized in that formed in the form of a pillow formed by connecting the projection and the groove portion is inserted into the head portion supporting the neck portion.
Wearing a filter on at least a portion of the human body to compensate for the difference in susceptibility between human tissue and the outside of the human body, the filter comprising a silicon pad comprising a silicon base of a silicon resin component; And

Resonance susceptibility difference compensation method comprising the step of obtaining a magnetic resonance image by applying a magnetic field.
The method of claim 12,

The silicon pad is magnetic resonance susceptibility difference compensation method characterized in that the addition of a hardening agent is capable of deformation.
The method of claim 12,

The silicon pad is magnetic resonance susceptibility difference compensation method characterized in that the compression deformation or close contact so as not to create a space between the applied human body parts.
The method of claim 12,

The magnetic resonance susceptibility difference compensation method further comprises a cover covering the surface of the silicon pad.