JPH06209918A - Rf probe for magnetic resonance photographing device - Google Patents

Abstract

PURPOSE:To provide an RF probe for magnetic resonance photographing device which is suitable for the brain function measurement. CONSTITUTION:On the outer wall of a bobbin 1, a multielement resonator 4 which consists of a plurality of electric conductive loops 2 and a capacity element 3 for resonance which is connected in series with each electric conductive loop is directly formed. On the outside of the bobbin 1, the second bobbin 5 made of acrylic resin exists, and a high frequency shield 6 which cuts off the outside high frequency noise and improves the S/N of the detection signal of the resonator is formed on the outer periphery. On the inner wall of the bobbin 1, a luminous element exists as inspected body stimulus element 7 in correspondence at the position of the eye of a specimen 9, and a noise generating element exists as a specimen stimulus element 8 in correspondence at the position of the ear of the specimen 9. Accordingly, the space can be utilized effectively, and a coil can be made compact and in a high sensitivity form, and the setting of the specimen can be carried out in one time at a stimulus part and at an electric conductive loop part, an troublesomeness can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention measures nuclear magnetic resonance (hereinafter referred to as "NMR") signals from hydrogen, phosphorus, etc. in an object and visualizes and displays nuclear density distribution, relaxation time distribution, etc. The present invention relates to an MRI RF probe for a magnetic resonance imaging (MRI) device, particularly suitable for brain function measurement.

[0002]

2. Description of the Related Art In an MRI apparatus, a resonance type high frequency coil detects a signal from a region of interest of a subject (for example, a person). Recently, it has been found that this MRI apparatus can measure human brain function. In this case, light or sound is used as a method of stimulating the human body. When measuring brain function by a method that does not use MRI, TV monitors, optical goggles, speakers and headphones are used for these stimuli. In the MRI experiment, the principle experiment of the brain function measurement of MRI can be performed by using these conventionally used stimulators.

[0003]

In general, the smaller the RF probe, which is the signal detecting section of MRI, the higher the sensitivity. Further, the gradient magnetic field coil that gives position information by the MRI apparatus is more efficient when it is smaller. Therefore, M of the human head
In RI, an RF probe and a gradient coil are placed in the immediate vicinity of the head so as to surround the head. In such a situation, there is a problem that conventional goggle for visual experiments and headphones for hearing experiments are too large to use. In order to improve this, there has been a problem that the RF probe and the gradient coil have to be unintentionally increased in size.

[0004]

To achieve the above object, an RF probe for a magnetic resonance imaging apparatus according to the present invention comprises:
A bobbin for accommodating the subject therein, a conductive loop fixed to the bobbin, a resonance capacitive element connected to the conductive loop, and a stimulating element fixed to the bobbin for stimulating the subject It The stimulating element is a light emitting element and is composed of a two-dimensional array element group. Further, the stimulating element is a sound wave generating element and is composed of a piezoelectric element. This sound wave generating element actively silences the sound generated by the gradient magnetic field coil as needed. When a heat element or chemical substance generating element is used as the stimulating element, a pipe for sending hot air or an olfactory stimulating substance fixed to the bobbin to the vicinity of the subject is provided.

[0005]

Since the subject stimulating element is fixed or integrally formed with the bobbin holding the conductive loop for RF transmission or reception, the space can be effectively used and the coil can be made small and highly sensitive. Further, since the setting of the subject can be performed by the stimulating portion and the conductive loop portion at the same time, the complexity is eliminated.

[0006]

The present invention will be described below with reference to the embodiment shown in FIG. FIG. 1A is a sectional view of the probe, FIG.
(B) is a side view of the probe. In FIG. 1, the bobbin 1 is made of acrylic. Inner diameter is 250 mm, outer diameter is 26
The length is 0 mm and the length is 300 mm. A multi-element resonator 4 including a plurality of conductive loops 2 and a resonance capacitive element 3 connected in series to each conductive loop is directly formed on the outer wall of the bobbin. Although not shown, the fixing is, for example, an insulating resin. The resonator is a high pass type,
12 elements, the resonance frequency of which is 63.8 MH
z. The length of the resonator is 23 cm. There is a second acrylic bobbin 5 on the outside of the bobbin. The inner diameter is 290 mm, the outer diameter is 300 mm, and the length is 300 mm. A high frequency shield 6 is formed on the outer circumference of the bobbin. This has a function of blocking external high frequency noise and improving the S / N of the detection signal of the resonator. On the inner wall of the bobbin 1, subject stimulating elements 7 and 8 are installed.
The stimulating element 7 is a light emitting element, and there are two stimulating elements corresponding to the positions of the eyes of the subject 9. The stimulating element 8 is a sound wave generating element and is the subject 9
There are two corresponding to the position of the ear. Although not shown, a soft light shielding member that excludes external light may be installed around the light emitting element. Although not shown, a soft sound insulating member that eliminates external sound may be installed around the sound wave generating element. In this embodiment, the analyte stimulating element is the bobbin 1.
Although it is installed on the inner surface of the bobbin 1, the bobbin 1 may be embedded by forming a recess. Further, if the bobbin 1 is transparent, it may be outside the bobbin 1. When the bobbin 1 is not transparent, a stimulating element can be similarly installed outside the bobbin by making a hole in the bobbin 1 if necessary.

A typical form of the photostimulation element 7 will be described. The device is composed of two arrays in which 5 × 5 light emitting diodes are arranged in a plane. The number of light emitting diodes may be increased if necessary, and for displaying a light emitting pattern generally used for brain stimulation, for example, a number of diodes of about 50 × 50 is more suitable. LE to display the light emission pattern
Besides D, an EL panel can also be used. A typical example of the sound wave generating element will be described. Operable in a strong magnetic field,
A piezoelectric element is used to generate sound waves of 0 Hz to 22 kHz. This includes, for example, lead zirconate titanate (PZT)
A material using a piezoelectric material such as or lead titanate (PZ) can be used. A thin film piezoelectric element such as zinc oxide ZnO is also suitable because it has a small occupied volume. These piezoelectric elements are suitable for stimulating the subject because the sound waves can be controlled arbitrarily by the voltage.
The sound wave generating element can be used for the following purposes in addition to the stimulation of the subject. Generally, in an MRI sequence for measuring brain function, a strong gradient magnetic field is applied. As a result, the gradient magnetic field coil oscillates due to the electric current flowing therein and generates a sound wave. This sound stimulates the subject's hearing and interferes with brain function experiments. Therefore, active muffling is performed using the sound wave generating element. This is to generate a sound wave having a phase opposite to that of the sound wave generated by the gradient magnetic field from the sound wave generating element so that the sound is canceled at the position of the subject. As a result, the subject is not stimulated by unnecessary sound, and brain function measurement under ideal conditions becomes possible.

In the control signal line of the stimulating element, an induced current is not generated by the RF magnetic field generated by the RF probe, and RF noise is externally introduced so that noise is not added to the reception signal of the RF probe. It is necessary to provide an RF filter. Although a large number of signal lines are required when controlling the light emitting elements by a matrix, the RF traps or filters used for these can be realized on a practical scale by forming them as patterns on the laminated substrate.
In this embodiment, the multiple element resonator is used as the RF probe, but another probe such as a circular surface coil may be used. Needless to say, the shape of the bobbin may be any other shape as long as it is within the scope of the present invention. Next, another embodiment will be described. This embodiment differs from the above-mentioned embodiments in that the stimulating element is a thermal element or a chemical substance generating element. Specifically, the thermal element is a ceramic heater, a piezo element, or the like, which is used to thermally stimulate the skin of the subject. It is more desirable that the installation position of the element be variable depending on the experiment. For the chemical substance generating element, for example, a method of applying a volatile substance on a thermal element and thermally controlling the evaporation amount of the chemical substance can be used. This stimulates the sense of smell of the subject. A pipe fixed to a bobbin may be used for the temperature stimulus and the olfactory stimulus, in addition to the stimulus element. As a result, hot air or an odorous substance can be sent to the vicinity of the subject from the outside.
When the pipe is fixed to the bobbin, there are advantages that the subject can be easily taken in and out and the efficiency of the experiment is improved.

[0009]

According to the present invention, the subject stimulating element is RF.
Since it is fixed to or integrally formed with the bobbin holding the conductive loop for transmission or reception, the space can be effectively used, and the coil can be made compact and highly sensitive. Further, since setting of the subject can be performed by the stimulating portion and the conductive loop portion at the same time, there is an advantage that complexity is eliminated.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Bobbin, 2 ... Conductive loop, 3 ... Resonance capacitive element, 4
... Multi-element resonator, 5 ... Acrylic bobbin, 6 ... High frequency shield, 7,8 ... Subject stimulator ...
9 ... Subject.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Takiguchi 1-280 Higashi Koikeku, Kokubunji City, Tokyo Metropolitan Research Laboratory, Hitachi Ltd. (72) Hiroyuki Itagaki 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Ltd. Central Research Laboratory (72) Inventor Etsuji Yamamoto 1-280 Higashi Koikekubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory

Claims (9)

[Claims] 1. A bobbin for accommodating a subject therein, a conductive loop fixed to the bobbin, a resonance capacitive element connected to the conductive loop, and a bobbin for stimulating the subject. RF probe for a magnetic resonance imaging apparatus including the stimulated element. 2. The RF probe for a magnetic resonance imaging apparatus according to claim 1, wherein the stimulating element is a light emitting element. 3. The RF probe for a magnetic resonance imaging apparatus according to claim 2, wherein the light emitting element comprises a two-dimensional array element group. 4. The RF probe for a magnetic resonance imaging apparatus according to claim 1, wherein the stimulating element is a sound wave generating element. 5. The RF for magnetic resonance imaging apparatus according to claim 4, wherein the sound wave generating element is a piezoelectric element.
probe. 6. The RF probe for a magnetic resonance imaging apparatus according to claim 4, wherein the sound wave generating element actively mutes the sound generated by the gradient magnetic field coil. 7. The RF probe for a magnetic resonance imaging apparatus according to claim 1, wherein the stimulating element is a thermal element. 8. The magnetic resonance imaging apparatus R according to claim 1, wherein the stimulating element is a chemical substance generating element.
F probe. 9. A bobbin for accommodating a subject therein, a conductive loop fixed to the bobbin, a resonance capacitive element connected to the conductive loop, and hot air or an odor stimulant fixed to the bobbin. An RF probe for a magnetic resonance imaging apparatus, which comprises a pipe for sending to the vicinity of the subject.