EP4200626A1 - Spulenarray und dessen verwendung - Google Patents
Spulenarray und dessen verwendungInfo
- Publication number
- EP4200626A1 EP4200626A1 EP21772666.0A EP21772666A EP4200626A1 EP 4200626 A1 EP4200626 A1 EP 4200626A1 EP 21772666 A EP21772666 A EP 21772666A EP 4200626 A1 EP4200626 A1 EP 4200626A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- coil
- array according
- coil array
- coils
- elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000035945 sensitivity Effects 0.000 claims description 11
- 206010002091 Anaesthesia Diseases 0.000 claims description 7
- 230000037005 anaesthesia Effects 0.000 claims description 7
- 239000003990 capacitor Substances 0.000 claims description 7
- 230000035764 nutrition Effects 0.000 claims description 7
- 235000016709 nutrition Nutrition 0.000 claims description 7
- 239000000523 sample Substances 0.000 claims description 6
- 238000009423 ventilation Methods 0.000 claims description 5
- 238000004611 spectroscopical analysis Methods 0.000 claims description 4
- 238000003325 tomography Methods 0.000 claims description 4
- 210000003128 head Anatomy 0.000 description 17
- 238000002595 magnetic resonance imaging Methods 0.000 description 10
- 241000282693 Cercopithecidae Species 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- 210000004556 brain Anatomy 0.000 description 6
- 238000003491 array Methods 0.000 description 5
- 210000003928 nasal cavity Anatomy 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000035515 penetration Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 210000001061 forehead Anatomy 0.000 description 2
- 230000036541 health Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 210000000214 mouth Anatomy 0.000 description 2
- 210000001331 nose Anatomy 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000008131 children development Effects 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000003203 everyday effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002847 impedance measurement Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 210000003695 paranasal sinus Anatomy 0.000 description 1
- 230000000241 respiratory effect Effects 0.000 description 1
- 230000029058 respiratory gaseous exchange Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
- G01R33/34046—Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
- G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
- G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
- G01R33/341—Constructional details, e.g. resonators, specially adapted to MR comprising surface coils
- G01R33/3415—Constructional details, e.g. resonators, specially adapted to MR comprising surface coils comprising arrays of sub-coils, i.e. phased-array coils with flexible receiver channels
Definitions
- the invention relates to a coil array and its use.
- Magnetic resonance imaging is one of the most powerful non-invasive medical imaging modalities used in everyday clinical practice. Over the past decade, tremendous technological advances have significantly improved image quality, thereby improving many clinical applications. Every MRI system consists of a number of subsystems that perform dedicated functions that are necessary for the MR image acquisition of an object. As one of the essential magnetic resonance (MR) components, the radio frequency (RF) system plays a key role in generating RF excitation pulses and receiving the MR signal.
- MR magnetic resonance
- RF radio frequency
- SNR signal-to-noise ratio
- the SNR increases approximately in proportion to the main magnetic field strength (Bo) [1]. For example, an SNR that is twice as high is obtained if the Bo is increased from 1.5 Tesla to 3 Tesla.
- the selection of an RF coil is usually based on the desired clinical applications.
- the main aspects to be considered are the image or examination area (FOV, "field-of-view"), the spatial resolution, the sensitivity and the ability for parallel imaging. "volume-of-interest”), which requires the purchase of a number of expensive RF coils to cover the imaging of different parts of the body.
- CONFIRMATION COPY is often chosen as a reference coil to evaluate the performance of newly developed arrays [6] [7] which can also be used for infant head examinations at 7 Tesla.
- Birdcage coils and multi-channel loop arrays are usually mounted on cylindrical housings. This severely limits accessibility, particularly to lines or tubing for anesthesia, artificial feeding, or respiratory equipment for infants [8] [9]. In order to avoid this problem, the diameter of the coil or array must inevitably be increased, which leads to a poor fill factor and thus to a deterioration in the SNR. Pure multi-channel receiving arrays can often be designed to be geometrically more flexible and can therefore be used together with a body coil without the problem of restricted accessibility. Body coils are usually installed in MRI scanners up to 3 Tesla, but not at field strengths of 7 Tesla or higher.
- Bo-shimming problems arise in MRI measurements of the brain mainly due to differences in susceptibility between air and biological tissue and are therefore particularly pronounced in the area of air-filled body cavities such as the mouth, nose and paranasal sinuses. In this area, therefore, the Bo field often cannot be sufficiently homogenized using conventional shim methods.
- the object of the invention to provide a coil array for magnetic resonance tomography which can be used in VOs such as subjects and patients, preferably children, in particular infants or small children, but also monkeys and biological tissue.
- the coil array should allow good or free access to supply lines, such as lines or hoses, for example for anesthesia, artificial nutrition or ventilation, and other patient connections, such as cables or probes, for example for measurement, without reducing the fill factor .
- the coil array according to the invention should have a high sensitivity, in particular re enable a high signal-to-noise ratio, particularly in the area of the brain, and reduce bo-shimming problems, particularly in the area of air-filled cavities, such as the nasal cavities, for example in brain MRI.
- the diameter of the coil or the coil array should be as small as possible, the fill factor should be increased and a good signal-to-noise ratio should be made possible, particularly when small objects to be examined, such as the heads of children or infants or monkeys biological tissue is to be examined by magnetic resonance imaging.
- the penetration depth of the RF fields should be improved.
- the coil array should enable the measurement of volumes to be examined, VOI, which are smaller than the standard adult head.
- the coil array should also be suitable for magnetic resonance imaging and magnetic resonance spectroscopy.
- VOI' such as test persons and patients, preferably children, in particular babies or small children, monkeys, in particular their heads, but also biological tissue by magnetic resonance imaging, with good or free access to feeds, such as lines or hoses, e.g. for anesthesia, artificial nutrition or ventilation, as well as other patient connections, such as cables or probes, e.g. for measurement, is made possible without reducing the fill factor or causing the risk of the hoses kinking.
- the coil array according to the invention has a high sensitivity, in particular a high signal-to-noise ratio, especially in the area of air-filled cavities, for example the forehead, and no or reduced bo-shimming problems, especially in the area of the nasal cavities, for example in brain MRT.
- the fill factor of the coil array is increased.
- the penetration depth of the RF fields into the object to be examined is improved and higher-quality images from deep regions are made possible.
- the coil array enables the measurement of volumes to be examined, VOI, which are smaller than the standard adult head.
- the coil array according to the invention can also be used for magnetic resonance tomography and magnetic resonance spectroscopy.
- the coil array consists of at least two coil elements, of which at least one coil element is curved and open, so that access from leads, such as at least one hose or other patient connection, to an object to be examined is made possible.
- This configuration of the coil array has the consequence that the problems with Bo-shimming, especially in the vicinity of the nasal cavities, are reduced.
- At least one coil element is curved and open makes it possible for a subject or a patient, in particular a small child or infant, or monkeys, in particular their heads or biological tissue, to be supplied with supplies such as ventilation hoses and/or hoses for anesthesia and /or the artificial nutrition, as well as other connections, such as patient connections, such as cables or probes, for example for measurement, can be supplied well.
- supplies such as ventilation hoses and/or hoses for anesthesia and /or the artificial nutrition
- other connections such as patient connections, such as cables or probes, for example for measurement
- the area of the air-filled cavities e.g. mouth, nose and nasal cavities in brain MRI always causes a bo-shimming problem.
- a higher sensitivity is obtained in the region of the forehead and the disturbance associated with Bo-shimming in the vicinity of air-filled cavities is reduced.
- An essential feature of the bent open dipole is its higher sensitivity in the feed area and the decrease in sensitivity towards the edge of the dipole antenna.
- An opening within the meaning of the invention is understood to mean an interruption in the coil or a gap in the coil, which results in the coil not having a closed geometry. This allows access to lines or hoses, for example for anesthesia, artificial nutrition or respiration, as well as other connections or patient connections, such as cables or probes, for example for measurement.
- Other coil elements can be closed. These closed coils can be surface coils or loop coils. These coils have no openings and are closed.
- a subject or patient preferably children, in particular infants or monkeys, and in particular their heads, but also biological tissue can be understood as an object to be examined within the meaning of the invention.
- Leads within the meaning of the invention can be understood to mean all possible feed lines, such as ventilation hoses and/or hoses for anesthesia and/or artificial nutrition, as well as other connections, in particular patient connections, or other feed lines, such as cables or probes, for example for measurement .
- the curved, open coil element enables a good supply of at least one supply or the hoses or cables mentioned, it can have an opening in the order of a few millimeters to a few centimeters and is advantageously based on the diameter of the hoses/patient connections provided.
- the interruption or opening can be 1 mm to 20 cm or 30 cm.
- the size of the interruption can be freely selected and can be adapted to the embodiment of the array according to the invention.
- the coil array according to the invention can have a plurality of coil elements.
- it can have 3, 4, 5, 6 or more, for example up to 16 or 32 individual coil elements.
- shapes with more than 32 elements are also possible.
- the coil array according to the invention preferably encloses the object to be examined completely or in a cylindrical arrangement around the object to be examined.
- the cylinder can advantageously taper conically into a cone or truncated cone, as a result of which better coverage of the object to be examined, for example the upper head, is achieved.
- the coil elements can be arranged in a row along the circumference of the cylinder which encloses a Z-axis and/or enclose the circumference or the axis of rotation of the cylinder, cone or truncated cone or be arranged along the circumference in such a way that they at least partially enclose it.
- the elements can be arranged freely, e.g. B. in several rows along the circumference of the cylinder or circumference of the truncated cone or in the shape of the hexagons of a soccer ball.
- the open or discontinuous or the open or discontinuous elements are arranged in such a way that they allow easy access to the hoses/patient connections.
- the open elements are preferably also arranged in such a way that they have little sensitivity in the area of the air-filled cavities and thus avoid bo-shimming problems.
- the volume enclosed by the coil array can be used in particular for examining small objects to be examined with a circumference of, for example, 35 cm to 45 cm.
- a human head typically has a volume of 1260 cm 3 for a male and 1130 cm 3 for a female, and an infant's head typically has a circumference of 35 cm to 45 cm.
- the coil array according to the invention is therefore suitable for use in the heads of adults, children, small children, infants or monkeys, which typically have the stated dimensions in the stated size range.
- the publication [12] discloses relevant dimensions of heads that can typically be examined with the coil array according to the invention. The head size measurements given in this publication are part of the disclosure of the application.
- At least one bent and open coil element must be present in order to achieve the effect according to the invention.
- the sensitivity in the area of the air-filled cavities can be adjusted in such a way that the Bo-shimming problem is largely reduced.
- the coil array can have 1 to 4 curved, open coils.
- the other coil elements can be closed coils or surface coils such as loop coils.
- the number of other surface coils or loop coils can be freely selected.
- the surface coils or loop coils each have at least one capacitor in order to produce resonance.
- the bent, open coil elements have no capacitor.
- the physical length of the bent, open coil elements can optionally be increased by the insertion of capacitors, e.g., if the dipole element is too short due to the wavelength.
- the coil elements each have means for impedance matching and means for feeding. These means can be implemented by a circuit block. The feed takes place at the point of impedance matching.
- the coil elements are decoupled from each other.
- means known from the prior art for decoupling the individual coil elements can be used.
- decoupling can be effected by overlapping common legs, capacitive decoupling or inductive decoupling as well as self-decoupling and appropriate means for this.
- An example is shown in the publication by Yan et al [13]. Combinations of different decoupling means can also be used.
- the size of the individual coil elements can be based on the object to be examined.
- the small dimensions of the coil array in connection with the configuration of the coil array according to the invention have the consequence that the image quality, in particular the signal-to-noise ratio, improves and Bo-shimming problems can be reduced, although supply lines, for example, to supply the living to object to be examined, such as a patient, with various hoses are present.
- the coil according to the invention enables a signal-to-noise ratio that is approx. 30% better than the prior art.
- a good fill factor is achieved by the design of the coil array according to the invention. With a coil array diameter of 26 cm for adult subjects and a smaller coil array with a diameter of 16 cm, the fill factor improves according to Equation 1
- the coil array according to the invention can be used in magnetic resonance tomography and in magnetic resonance spectroscopy, especially when examining small objects to be examined, especially children, small children, infants and monkeys, especially their heads, but also biological tissue and in MR-compatible versions of newborn incubators.
- the figures show coil arrays in schematic form.
- Fig.1 A coil array according to the prior art
- FIG. 1 shows a coil array according to the prior art. It comprises several coils 1, 1a, 1b, 1c. Each coil has capacitors 2, 2a, 2b, 2c..., and a unit for feeding and impedance measurement 3.
- Reference number 4 designates means for decoupling the coils.
- a coil element 5 is bent and interrupted in a partial area, or not closed.
- FIG. 3 shows a further embodiment of the coil array according to the invention, in which the individual coils are arranged in a cylindrical geometry. It is made clear that the coil geometry in the area of the individual open coil element used as an example in FIG. 2 has an opening through which hoses and/or patient connections can be routed to the patient or subject (FIG. 3, right). The conventional coil arrangement with closed conductor loops according to FIG. 1 cannot be opened at this point because of the conductor present there (FIG. 3, left).
- FIG. 4 shows axial MR images which were recorded using a conventional 1-channel loop coil and a circular 1-channel dipole antenna according to the prior art.
- the white dashed box in Figure 4 marks the area in which the object is positioned and the SNR is calculated.
- a circularly curved dipole with a diameter of 12 cm was used for the recording by means of the dipole element according to the invention on the right-hand side of FIG. State of the art:
- WHO child growth standards head circumference-for-age, arm circumference-forage, triceps skinfold-for-age and subscapular skinfold-for-age : methods and development.
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Magnetic Resonance Imaging Apparatus (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102020005044.1A DE102020005044A1 (de) | 2020-08-18 | 2020-08-18 | Spulenarray und dessen Verwendung |
PCT/DE2021/000132 WO2022037737A1 (de) | 2020-08-18 | 2021-08-12 | Spulenarray und dessen verwendung |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4200626A1 true EP4200626A1 (de) | 2023-06-28 |
Family
ID=77801421
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP21772666.0A Withdrawn EP4200626A1 (de) | 2020-08-18 | 2021-08-12 | Spulenarray und dessen verwendung |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4200626A1 (de) |
DE (1) | DE102020005044A1 (de) |
WO (1) | WO2022037737A1 (de) |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4885541A (en) * | 1988-08-19 | 1989-12-05 | General Electric Company | Apparatus and method for enhanced multiple coil nuclear magnetic resonance (NMR) imaging |
US20040015074A1 (en) * | 2002-05-16 | 2004-01-22 | Ravi Srinivasan | Radio frequency coil for resonance imaging analysis of pediatric patients |
US6762606B2 (en) * | 2002-11-22 | 2004-07-13 | Igc-Medical Advances, Inc. | Retracting MRI head coil |
DE102006050104B4 (de) * | 2006-10-24 | 2010-03-18 | Siemens Ag | MR-Kopfspule |
DE102010033322A1 (de) * | 2010-08-04 | 2012-02-09 | Siemens Aktiengesellschaft | Mechanisch flexible MR Spule mit öffnungsfähigen Leiterstrukturen für insbesondere interventionelle MRT |
US9972914B2 (en) * | 2013-11-15 | 2018-05-15 | New York University | Monopole array arrangement, computer-accessible medium and method for using the same |
US10132884B2 (en) | 2013-11-15 | 2018-11-20 | New York University | Circular dipole and surface coil loop structures and methods for using the same |
KR101822384B1 (ko) * | 2016-12-01 | 2018-03-09 | 가천대학교 산학협력단 | 굽은형 다이폴 안테나를 이용한 자기공명 영상용 rf 코일 |
WO2018175530A1 (en) | 2017-03-22 | 2018-09-27 | Vanderbilt University | Self-decoupled rf coil array for mri |
-
2020
- 2020-08-18 DE DE102020005044.1A patent/DE102020005044A1/de active Pending
-
2021
- 2021-08-12 WO PCT/DE2021/000132 patent/WO2022037737A1/de unknown
- 2021-08-12 EP EP21772666.0A patent/EP4200626A1/de not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
DE102020005044A1 (de) | 2022-02-24 |
WO2022037737A1 (de) | 2022-02-24 |
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