JP5184866B2 - Receiving coil device and MR observation device - Google Patents

Description

  The present invention relates to a receiving coil device that is inserted into a patient's body and receives a magnetic resonance signal.

  By utilizing the nuclear magnetic resonance (hereinafter referred to as “MR”) phenomenon, a human body can be diagnosed in a minimally invasive manner using an MR apparatus. The MR phenomenon is a phenomenon in which a certain nucleus resonates and absorbs electromagnetic wave energy of a specific wavelength in a magnetic field and emits it as an electromagnetic wave. In an MR apparatus, a human body is placed in a static magnetic field, a high-frequency magnetic field having a predetermined frequency is applied to the human body to excite nuclei having spin in the human body, and a predetermined frequency generated while the excited nucleus returns. A tomographic image of the human body can be obtained by detecting MR signals and processing them with a computer.

  In general, such an MR apparatus mainly includes a single cylindrical magnet, an RF (high frequency) coil, an MR signal receiving coil, and a control unit. A single cylindrical magnet generates a uniform static magnetic field over almost the entire human body. The RF coil applies a high-frequency magnetic field having a predetermined frequency to a human body placed in a static magnetic field. The MR signal receiving coil detects an MR signal having a predetermined frequency emitted from an excited nucleus having spin in the human body. The control unit processes a detection signal from the MR signal detection coil to obtain a tomographic image of the human body.

  In recent years, an insertion tool such as an endoscope probe has been proposed in which a high-frequency coil for receiving MR signals is provided at the distal end of an insertion portion to be inserted into a patient's body. However, when an MR signal receiving coil is incorporated in an endoscope in which an observation optical system, an illumination optical system, and the like are incorporated at the distal end of the insertion portion to be inserted into the patient's body, the distal end of the endoscope insertion portion The outer diameter of the part tends to increase. Therefore, the burden on the patient when inserting the MR endoscope incorporating the MR signal receiving coil into the patient's body is increased.

  Therefore, in Cited Document 1, an MR image in the body cavity is obtained by the high frequency coil for magnetic resonance observation in the high frequency coil housing portion, and an inner peripheral surface of a hard cylindrical body constituting the high frequency coil housing portion is interposed via an adhesive layer. An MR endoscope for magnetic resonance observation in which a high-frequency coil and a high-frequency coil fixing member are sequentially arranged is disclosed. Thereby, the high frequency coil for magnetic resonance observation is incorporated in a compact manner without increasing the outer diameter of the insertion portion of the insertion tool such as an endoscope.

In the cited document 2, for receiving MR signals, a flexible non-magnetic sheet having biocompatibility and a detection coil that is embedded in the sheet and detects a nuclear magnetic resonance signal having a predetermined frequency emitted from a human body. A surface coil is disclosed. By inserting this MR signal receiving surface coil into the body cavity and receiving the MR signal, all the organs in the abdominal cavity can be easily accessed and an MR image in a desired range can be obtained with high resolution. be able to.
Japanese Patent Laid-Open No. 06-304152 JP 09-094236 A

  The imaging range of the body cavity receiving coil for magnetic resonance observation is determined according to the diameter of the coil. Therefore, when imaging a region having a certain depth and width in the body cavity, a coil having a diameter larger than the diameter of the endoscope is required. However, since the coil needs to be able to be inserted from the esophagus or the like, if the diameter is large when inserted into the body cavity, the coil cannot be inserted.

  In Cited Document 1, a receiving coil for magnetic resonance observation is compactly incorporated at the distal end portion of an endoscope to prevent the outer diameter of an insertion portion of an insertion tool such as an endoscope from being increased. However, since the receiving coil is fixed in the endoscope, it does not have a diameter larger than the diameter of the endoscope.

  On the other hand, the surface coil described in the cited document 2 is composed of a flexible mesh-like nonmagnetic sheet in which an MR signal detection coil is embedded. This surface coil can be introduced into the abdominal abdominal cavity through a guide hole of a trocar inserted into the abdominal wall in a state of being wound in a cylindrical shape or folded. However, in the cited document 2, it is necessary to develop and spread the surface coil with grasping forceps and arrange it at a desired surface position in the living body, which is troublesome. Further, when the receiving coil is discharged out of the body, it is not disclosed that the surface coil thus spread is accommodated again in the guide hole of the trocar.

  In view of the above problems, the present invention provides a receiving coil device in which the outer shape of the receiving coil is small when introduced into and discharged from a body cavity, and the receiving coil is widened when an MR image is captured.

A receiving coil device that can be inserted into a tube inserted into a body cavity and that is used in an MR observation device that captures a magnetic resonance (MR) image according to the present invention has a planar elasticity in which a resonance circuit that receives an MR signal is arranged. The planar elastic member connected to the planar elastic member and passed through the tube and supplying the received MR signal to the MR observation device, and is rolled and inserted into the tube The member expands when coming out from the tip of the tube due to the elastic force of the planar elastic member, and when the cable is pulled, the member is curled again by contact with the opening of the tube and stored in the tube. .

  In the receiving coil device, an end of the planar elastic member connected to the cable is inclined at a predetermined angle with respect to the longitudinal direction of the cable.

  In the receiving coil device, the circuit includes a plurality of coils and a plurality of capacitors, and the capacitors are arranged in a direction perpendicular to a direction in which the planar elastic member is rounded.

In the receiving coil device, a hole having a predetermined shape is formed in the center of the planar elastic member.
According to the present invention, in the MR observation device for taking a magnetic resonance (MR) image by inserting a receiving coil device into a tube inserted into a body cavity, the receiving coil device is provided with a resonance circuit for receiving MR signals. A planar elastic member, and a cable connected to the planar elastic member and passed through the tube and supplying the received MR signal to the MR observation device, and is rolled and inserted into the tube. The planar elastic member spreads out from the tip of the tube due to the elastic force of the planar elastic member, and when the cable is pulled, the planar elastic member is curled again by contact with the opening of the tube and stored in the tube. It is characterized by.

In the MR observation device, the end of the planar elastic member on the side connected to the cable is inclined at a predetermined angle with respect to the longitudinal direction of the cable.
In the MR observation apparatus, the circuit includes a plurality of coils and a plurality of capacitors, and the capacitors are arranged in a direction perpendicular to a direction in which the planar elastic member is rounded.

  In the MR observation apparatus, a hole having a predetermined shape is opened at the center of the planar elastic member.

  By using the present invention, the outer shape of the receiving coil can be reduced when introduced into the body cavity and discharged from the body cavity, and the receiving coil device can be widened when MR images are captured.

<First Embodiment>
FIG. 1 shows a body cavity MR signal receiving coil according to this embodiment. The body cavity MR signal receiving coil 1 includes a receiving mechanism 2, a coaxial cable 10, a decoupling circuit 11, and a BNC connector 12. Hereinafter, a configuration of the body cavity MR signal receiving coil 1 will be described.

  A receiving mechanism 2 is provided at one end of the coaxial cable 10. The receiving mechanism unit 2 is provided with a coil unit 3, a capacitor unit 4, a tuning unit 5, a matching unit 6, and a coaxial cable 10 on a flexible planar elastic member 7. In the present embodiment, a flexible printed circuit board (FPC) using a polyimide film or the like as an insulating film is used as an example of the flexible planar elastic member 7, but is not limited thereto.

  The coil unit 3 and the capacitor unit 4 (4a, 4b, 4c, 4d) form a resonance circuit with an inductance L and a capacitance C. This resonance circuit can receive an electromagnetic wave (MR signal) having a predetermined frequency.

  The tuning unit 5 is a capacitor for adjusting the frequency to a predetermined frequency generated by resonance of hydrogen (proton). The matching unit 6 is a capacitor for adjusting the characteristic impedance to a predetermined resistance value (for example, 50Ω).

  The coaxial cable 10 transmits the MR signal received by the receiving mechanism unit 2 to the MR apparatus. A decoupling circuit 11 is provided in the middle of the coaxial cable 10. The decoupling circuit 11 is a circuit for causing the body cavity MR signal receiving coil 1 to function exclusively for reception.

A BNC connector 12 is provided at the other end of the coaxial cable 10. The BNC connector 12 is a connector for connecting the coaxial cable 10 to the MR apparatus.
FIG. 2 shows the receiving mechanism 2 of the MR signal receiving coil 1 for body cavity in the present embodiment. As shown in the figure, the receiving mechanism unit 2 has a substantially spoon shape. That is, the FPC 7 has a wide width in the portion where the coil portion 3 and the capacitor groups 4a, 4b, and 4d are arranged, and is gradually narrowed from the vicinity of the capacitor group 4c to the tuning portion 5 (the inclined portion 22). Reference numerals 24 and 25 are jumper lead lands, and the land 24 and the land 25 are connected by jumper leads. Reference numerals 26 and 27 are electrode pads, which are connected to the coaxial cable 10 respectively.

  A reinforcing plate 23 is provided in a portion where the capacitor group 4c, the tuning unit 5, and the matching unit 6 are disposed to withstand stress related to FPC when the coaxial cable 10 is pulled.

  In the figure, the coil forming the coil portion 3 is wound four times. One turn (one turn) of the coil is substantially equally divided into four, and a capacitor 4 is provided in the divided portion. Capacitors 4 are arranged in several places to form capacitor groups 4a, 4b, 4c and 4d.

Further, the receiving mechanism unit 2 will be described in detail. As described above, in order to receive a high-intensity MR signal with the body cavity MR signal receiving coil 1, it is necessary to match the frequency of the receiving coil with the frequency from the MR apparatus. The resonant frequency of the LC resonant circuit is proportional to 1 / (LC) ^1/2 . Since L is determined by the coil shape, the resonance frequency can be adjusted by C.

  Here, the capacity of the existing chip capacitor is limited. When a capacity below this limit is required, the coil loop is divided and a capacitor is inserted into the divided portion. As a result, the capacity of the capacitor used for the divided portion is doubled by the number of divisions, such as 2 for 2 divisions, 3 for 3 divisions,..., N for n divisions. As a result, the usable capacitor capacity can be increased, so that C can be adjusted.

  By the way, if a capacitor is arranged on the FPC, even an originally flexible FPC loses its flexibility and becomes rigid, and the substrate cannot be rounded to a desired shape. Further, if stress is applied to the capacitor portion, the capacitor may be soldered.

  The number of divisions per coil winding varies depending on various conditions and cannot be generally specified. However, in the case of a plurality of winding coils, it is desirable that the intervals between the coils be equal. Then, for example, when one turn of the coil is divided into four, the capacitors are collected at four locations.

  In this case, when the capacitor groups 4a, 4b, 4c, and 4d are arranged along the direction in which the FPC 7 is rounded, the arranged portion becomes a rigid body. Therefore, it is difficult to round the FPC 7 to a diameter that can be inserted into the body cavity. Therefore, the capacitors forming each capacitor group are arranged so as to be aligned in a direction perpendicular to the direction in which the FPC 7 is rounded. Similarly, the capacitor groups 4a and 4c are also arranged so as to be aligned in a direction perpendicular to the direction in which the FPC 7 is rounded.

  Next, the operation of the body cavity MR signal receiving coil 1 will be described. First, the body cavity MR signal receiving coil 1 is inserted into the body cavity. Then, when the MR apparatus is operated, nuclei having spin in the human body are excited by the static magnetic field generated by the MR apparatus. The receiving mechanism unit 2 of the body cavity MR signal receiving coil 1 receives an MR signal of a predetermined frequency emitted by the excited nucleus. The MR signal received by the receiving mechanism unit 2 is transmitted to the MR apparatus via the coaxial cable 10. In the MR apparatus, the MR signal is processed to generate an MR image. The generated MR image is displayed on the monitor.

  By the way, the receiving mechanism part 2 of the MR signal receiving coil 1 for body cavity can be introduced into the body cavity by using the inside of the tube inserted into the body as a guide. Therefore, the receiving mechanism part 2 of the MR signal receiving coil 1 for body cavity is composed of the FPC 7, the receiving mechanism part 2 is rounded and loaded into a tube, put into the body via the esophagus, etc., and taken out of the tube. When the FPC 7 is recovered from the body, it is necessary to be accommodated in the tube again in the method of automatically deploying in a substantially flat shape by the elastic force of. However, providing a mechanism for rounding the FPC 7 causes problems such as a complicated structure, an increase in volume when rounded, and an increase in cost.

  Therefore, when collecting the receiving mechanism portion 2 that has jumped out of the tube from the tip of the tube, the tube side end of the FPC 7 is pulled with a cable or forceps connected to the tube side end of the FPC. Then, when the end surface of the FPC 7 hits the opening of the tube, the FPC 7 itself is rolled along the shape of the opening of the tube so as to fit in the tube. That is, as indicated by reference numeral 22, the end surface of the FPC 7 is formed at an angle of about 45 degrees or less than 45 degrees in the longitudinal direction of the tube, and is automatically rounded to the side with the ridges in advance.

  FIG. 3 shows a process of storing the body cavity MR signal receiving coil 1 in the tube of the receiving mechanism section 2 in this embodiment. FIG. 3A shows a developed state of the FPC 7. FIG. 3B shows a state in which the FPC 7 is being housed in the tube 30. FIG. 3C shows a state in which the FPC 7 is stored in the tube 30. The tube 30 may be an endoscope.

  First, the FPC 7 as the receiving mechanism unit 2 is rolled and loaded into the tube 30, and then the FPC 7 is taken out from the tip of the tube 30. Then, the rounded PPC 7 is automatically spread in a substantially planar shape by the elastic force (FIG. 3A). In this state, the MR signal receiving coil 1 for body cavity is operated to take an MR image.

  After the MR image is captured, the coaxial cable 10 is pulled. Then, due to the shape of the inclined portion 22 described above, as the coaxial cable 10 is pulled, the contact point between the inclined portion 22 of the FPC 7 and the tip of the tube 30 rises along the shape of the inclined portion 22. The FPC 7 is also housed in the tube (FIG. 3B).

  When the contact point between the inclined portion 22 of the FPC 7 and the tip of the tube 30 finishes moving up the inclined portion 22, the FPC 7 is rounded to the same length as the inner diameter of the tube 30. When the coaxial cable 10 is further pulled, the FPC 7 is completely accommodated in the tube 30 (FIG. 3C).

  According to the present embodiment, since the diameter of the coil is larger than the diameter of the tube or the endoscope when MR images are captured, an image with a deep depth can be obtained. In addition, both sides of the end of the FPC connected to the coaxial cable are inclined with respect to the longitudinal direction of the coaxial cable, thereby reducing friction with the tube opening and facilitating storage in the tube. ing. Further, the FPC 7 can be easily rounded by arranging the capacitors so as to be arranged in a direction perpendicular to the direction in which the FPC 7 is rounded.

<Second Embodiment>
FIG. 4 shows the receiving mechanism 2 of the body cavity MR signal receiving coil 1 according to this embodiment. The body cavity MR signal receiving coil 1 of FIG. 4 has a hole 40 formed at the center of the receiving mechanism 2 of the body cavity MR signal receiving coil 1 of the first embodiment.

  In the case where the receiving mechanism unit 2 comes out of the tube tip or is housed in the tube, an inclination is formed with respect to the longitudinal direction of the tube 30 so that the hole 40 is not caught in the opening of the tube. The shape is approximately rhombus.

According to the present embodiment, the treatment tool or the like can be approached to the affected part through the hole 40, so that the treatment work while viewing the MR image becomes very easy.
The present invention is not limited to the above-described embodiment, and various configurations or embodiments can be taken without departing from the gist of the present invention.

1 shows a body cavity MR signal receiving coil according to a first embodiment. The receiving mechanism part 2 of the MR signal receiving coil 1 for body cavity in 1st Embodiment is shown. The accommodation process to the tube of the receiving mechanism part 2 of the MR signal receiving coil 1 for body cavity in 1st Embodiment is shown. The receiving mechanism part 2 of the MR signal receiving coil 1 for body cavity in 1st Embodiment is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 MR signal receiving coil for body cavity 2 Reception mechanism part 3 Coil part 4 Capacitor part 4a, 4b, 4c, 4d Capacitor group 5 Tuning part 6 Matching part 7 FPC
10 Coaxial cable 11 Decoupling circuit 12 BNC connector 22 Inclined part 23 Reinforcing plate 30 Tube 40 Hole

Claims (8)

A receiving coil device that can be inserted into a tube inserted into a body cavity and is used in an MR observation device that takes a magnetic resonance (MR) image
A planar elastic member in which a resonance circuit for receiving an MR signal is disposed;
A cable connected to the planar elastic member and passed through the tube to supply the received MR signal to the MR observation device;
Equipped with a,
The planar elastic member that is rolled up and inserted into the tube spreads out from the tip of the tube due to the elastic force of the planar elastic member, and when the cable is pulled, it again comes into contact with the opening of the tube. A receiving coil device which is curled and stored in the tube . The receiving coil device according to claim 1, wherein an end portion of the planar elastic member connected to the cable is inclined at a predetermined angle with respect to a longitudinal direction of the cable. The receiving coil device according to claim 1, wherein the circuit includes a plurality of coils and a plurality of capacitors, and the capacitors are arranged in a direction perpendicular to a direction in which the planar elastic member is rounded. . The receiving coil device according to claim 1, wherein a hole having a predetermined shape is opened at a center of the planar elastic member. An MR observation device for taking a magnetic resonance (MR) image by inserting a receiving coil device into a tube inserted into a body cavity,
The receiving coil device includes:
A planar elastic member in which a resonance circuit for receiving an MR signal is disposed;
A cable connected to the planar elastic member and passed through the tube to supply the received MR signal to the MR observation device;
Equipped with a,
The planar elastic member that is rolled up and inserted into the tube spreads out from the tip of the tube due to the elastic force of the planar elastic member, and when the cable is pulled, it again comes into contact with the opening of the tube. An MR observation apparatus which is curled and stored in the tube . The MR observation apparatus according to claim 5 , wherein an end portion of the planar elastic member connected to the cable is inclined at a predetermined angle with respect to a longitudinal direction of the cable. The MR observation apparatus according to claim 5 , wherein the circuit includes a plurality of coils and a plurality of capacitors, and the capacitors are arranged in a direction perpendicular to a direction in which the planar elastic member is rounded. . The MR observation apparatus according to claim 5 , wherein a hole having a predetermined shape is opened at a center of the planar elastic member.