JP3461380B2 - Apparatus for determining measurement position in biological function measurement - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biofunction imaging apparatus capable of quickly determining a measurement position of a biofunction.

[0002]

2. Description of the Related Art Advanced science and technology have made it possible to non-invasively image biological information. The biometric information roughly includes morphological information and functional information. Further, in order to obtain biological information, a method of passively receiving a signal generated by a living body such as brain potential or magnetoencephalography, an ultrasonic echo device, a magnetic resonance imaging device, or an X-ray device.
Energy (such as ultrasound, magnetism, X
There is a method of receiving the signal emitted from the body when a (ray) is given from the outside of the body, and a method of receiving the radiation emitted by the radioactive isotope put into the body outside the body such as a γ camera and a positron emission computed tomography device.

The difference in these methods reflects the difference in the obtained biometric information, and the biometric information obtained by the apparatus is different even with the same method. In order to make more accurate medical diagnosis and physiological examination, it is necessary to collect more information, and it is essential to collect information by multiple non-invasive measurement methods.

At present, as one type of medical information processing, by centrally managing the biometric information obtained by the above-mentioned methods, a plurality of morphological information and functional information obtained by a patient can be obtained. A device that is instantly presented to a doctor who diagnoses a patient has been studied. This device is expected to improve the accuracy of diagnosis and reduce the burden on medical staff.

[0005]

[Problems to be Solved by the Invention] By measuring a plurality of functions for improving the accuracy of medical diagnosis and physiological examination,
Subject restraint time increases. The problem to be solved by the present invention is to realize the restraint time of the subject by shortening the time required to measure each function.

[0006]

[Means for Solving the Problems] The above problems are to use the function information obtained by other function measurement to determine the measurement position in the function measurement, and to fix the subject by a method common to a plurality of function measurements. And it can be solved by detecting the movement.

[0007]

For example, a subject who receives the brain function measurement by magnetic resonance imaging for the first time has no criterion for selecting the slice position. Similarly, in brain function measurement using biomagnetism, there is no standard for selecting the position of the detection coil. But,
If the position of cranial nerve activity is known by brain function measurement using biomagnetism, it is possible to estimate the optimal slice position for brain function measurement by magnetic resonance imaging based on that. On the contrary, if the position of the cranial nerve activity is already known by the brain function measurement by magnetic resonance imaging,
Based on this, it is possible to estimate the optimum detection coil position when measuring brain function using biomagnetism.

According to the present invention, the function information, the measurement position estimated by a computer based on the function information, and the morphological information if known are presented to the measurer to assist the measurer in positioning.

At this time, the degree of fixation of the subject in each function measurement, the position measurement accuracy, and the accuracy of coordinate adjustment between the measurements have a great influence on the obtained result. By using the fixture of the present invention, the subject can be fixed to the measuring device and the movement of the subject can be monitored. Further, when the subject moves, it is possible to correct the collected data from the position of the subject obtained by using the marker attached to the subject and the measuring device for the position. Furthermore, by using the fixture and the position measuring device for each functional measurement, the coordinates between the measurements can be matched.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a biological function imaging apparatus equipped with the present invention. In the figure, 32 is a biological function measuring device such as a magnetic resonance imaging device or a biomagnetic measuring device, and 33 is a part of the present invention, and the measurement position is estimated based on the functional information and morphological information of the biological body. , A workstation that presents the results.

FIG. 2 is a block diagram showing an example of a brain function measuring apparatus by magnetic resonance imaging in a biological function imaging apparatus. In the figure, 1 is a magnet for producing a static magnetic field, 2 is a probe for transmitting and receiving high-frequency magnetic field, 3 is a subject, 4 is a bed for supporting the subject, and 5 is a fixture for fixing the head of the subject to the probe 2. A workstation 10 collects and analyzes data and determines a slice position.

FIG. 3 is an enlarged view of the vicinity of the probe 2. 6
Is a glass ball filled with fat attached to the head of the subject as a marker, 7 is an ultrasonic transmitting / receiving device for measuring the position of the marker 6, and 8 is a subject's head by injecting nitrogen gas in the fixture 5. Is fixed to the probe, and 9 is a part of the fixture 5 between the marker 6 and the ultrasonic transmission / reception device 7 for transmitting ultrasonic waves.

FIG. 4 shows S of the biological function imaging apparatus.
It is explanatory drawing which shows an example of the cerebral magnetic field measurement apparatus using a QUID magnetometer. In the figure, 11 is a magnetically shielded room that shields the earth's magnetism and magnetic fields generated by surrounding devices, and 12 is a SQUID.
Dewar, 13 is a gantry that supports the SQUID dewar, 14 is a subject, 15 is a bed that supports the subject, 1
6 is a display device that presents the measurement position of the brain magnetic field distribution and the position of the SQUID dewar 12, 17 is data collection / analysis,
A workstation that determines the position of the magnetic detection coil,
Reference numeral 18 denotes a fixture that is erected on the bed to fix the subject head to the bed, and 19 is a fixture that is inserted between the subject head and the fixture 18 to fix the subject head to the bed.
SQUID Dewar 12 has SQ made of superconducting material
The UID and the detection coil and the insert holding them are housed inside, and liquid helium is filled as a refrigerant that keeps the temperature below the critical temperature of the superconducting material.

FIG. 5 is an enlarged view of the vicinity of the fixture 18. Two
0 is a glass bulb in which fat is enclosed, which is attached to the subject's head as a marker, 21 is an ultrasonic wave transmitting / receiving device for measuring the position of the marker 20, and 22 is a fixture 19 for injecting gas to fix the subject's head. A portion 23 fixed to the probe is a portion of the fixture 19 between the marker 20 and the ultrasonic transmission / reception device 21 for transmitting ultrasonic waves.

First, an outline of a biological function imaging apparatus taken as an embodiment of the present invention will be described. The imaging device is composed of a plurality of biological function measuring devices.
When performing the biological function measurement, the function information from the biological function measuring device 32 that has already been measured, the optimum measurement position estimated from this information, and the morphological information if known are displayed on the workstation 33. , Supports the determination of the measurement position for the next functional measurement. The steps performed by the workstation 33 may be performed by the workstation included in each biological function measuring device.

Next, the case where the brain function measurement is performed by the magnetic resonance imaging apparatus after the brain function measurement is performed by the brain magnetic field measurement apparatus will be described. Prior to the measurement of the brain magnetic field, the subject having the marker attached to the head is laid on the bed 15. Nitrogen gas is injected into the portion 22 of the fixture 19, the head of the subject and the fixture 18 are compressed and fixed, and the position of the marker 20 is measured by ultrasonic scanning with the ultrasonic transmitting / receiving device 21.

After that, the SQUID dewar 12 is closely fixed to the head of the subject 14 and the brain magnetic field is measured. The current dipole as a signal source is estimated from the measured cerebral magnetic field distribution by using the least square method or the like. For the estimation results assuming a current distribution, the center of gravity, midpoint, and average of the distribution are used. During the brain magnetic field measurement, the strain gauge attached to the surface of the fixture 19 and the pressure sensor installed at the inlet of nitrogen gas to the portion 22 of the fixture 19 detect the movement of the subject's head, and the ultrasonic transmitter / receiver 21 Check the position of the marker 20. If the subject's head moves, the measurer is warned via the workstation 17 to request a decision to interrupt or continue the measurement. At the same time, the amount of movement of the subject's head is recorded and saved.

Using the information of this current dipole, brain function measurement is performed by magnetic resonance imaging. The subject with the marker 6 attached at the same position as when the brain function was measured by the brain magnetic field measurement device was laid on the bed 4 and nitrogen gas was injected into the portion 8 of the fixture 5 to press the subject's head and the probe 2. Fix it. After that, the position of the head of the subject is examined by measuring the position of the marker 6 by ultrasonic scanning with the ultrasonic transmission / reception device 7.

The workstation 10 is presented with a current dipole 24 and a slice 25 containing it as shown in FIG. If there is a brain morphological image 26 as morphological information obtained by the magnetic resonance imaging apparatus, it may be superposed on it. The slice position is determined by the measurer's judgment and brain function is measured. During the brain function measurement, the strain gauge attached to the surface of the fixture 5 and the fixture 5
The movement of the subject's head is detected by the pressure sensor installed at the inlet of the nitrogen gas to the portion 8 and the position of the marker 6 is checked by the ultrasonic transmission / reception device 7. If the subject's head moves, the operator is warned via the workstation 10,
Request a decision to suspend or continue measurement. At the same time, the amount of movement of the subject's head is recorded and saved.

Next, the case where the brain function measurement is performed by the brain magnetic field measurement apparatus after the brain function measurement is performed by the magnetic resonance imaging apparatus will be described. A subject with the marker 6 attached on the head surface is laid down on the bed 4, nitrogen gas is injected into the portion 8 of the fixture 5, and the subject's head and the probe 2 are compressed and fixed. Further, the position of the head of the subject is examined by measuring the position of the marker 6 by ultrasonic scanning with the ultrasonic transmission / reception device 7. The measurer determines a slice based on past experience and knowledge and measures a functional brain image. A morphological image of the brain is also measured as morphological information. During the measurement, the movement of the subject's head is examined as described above.

Using this brain function image, brain function measurement is performed by a brain magnetic field measuring device. The detection coil of the SQUID magnetometer is an axial gradiometer. First, the marker 2 is placed at the same position as in the case of brain function measurement by magnetic resonance imaging.
The position of the marker 20 on the head surface is fixed by injecting nitrogen gas into the portion 22 of the fixture 19 to fix the subject's head and the fixture 18 at a position where the subject 14 wearing 0 is in a comfortable posture. Is measured by the ultrasonic transmission / reception device 21 to check the position of the subject's head.

Next, at which position on the head of the subject the cerebral magnetic field is measured is determined by the procedure shown in the flowchart of FIG. First, the measurer looks at an image as shown in FIG. 7, such as a brain morphology image 27 and a brain function image 28, presented on the workstation, estimates the signal source position and direction of the brain magnetic field distribution to be measured, and then estimates the position. Is input to the workstation 17. It is different by calculating the brain magnetic field measurement position that minimizes the evaluation function such as Equation 1 from the distribution of the magnetic field generated by the signal source of the input position and direction on the head surface by the least square method or the like. A detection coil position including two peaks having polarities, the polarities of the respective peaks being spatially uniform, and the distance from the head surface to the detection coil being the shortest is estimated.

[0023]

[Equation 1]

Further, this result is obtained by the workstation 17
To present. When the measurer determines that this measurement position is appropriate, the process moves to the SQUID dewar movement step. If it is determined to be inappropriate, a new signal source position is input and the operation is repeated. Alternatively, the measurer directly inputs the measurement position and moves to the SQUID dewar movement step.

As the brain functional image 28, a t-test image in which the difference between the magnetic resonance imaging image in the activated state of the brain and the magnetic resonance imaging image in the non-activated state of the brain is expressed by using the result of the statistical t-test. To use. F-test and χ
A square test or the like may be used. As the brain functional image, the difference between the magnetic resonance image in the activated state of the brain and the magnetic resonance imaging image in the non-activated state of the brain may be used as it is.

In order to measure the cerebral magnetic field in the center of the magnetically shielded room in which the environmental magnetic noise is minimized, the SQU is set so that the position of the detection coil determined in the above step becomes the center position.
Determine the ID Dewar position. When the measurer moves the SQUID dewar 12, for example, as shown in FIG.
The measurement position 29 of the brain magnetic field with respect to the brain morphology image 31 of the subject and the current detection coil position 30 are displayed on the display device 16 so that the measurer can grasp the positional relationship between the measurement position and the SQUID dewar. After fixing the SQUID dewar at the measurement position, the brain magnetic field is measured. During the measurement, the movement of the subject's head is examined as described above.

Functional measurement can be performed on other organs by the same procedure. For example, when investigating changes in lung function due to a small amount of magnetic substance accumulated in the lung, first measure the position of the magnetic substance with a biomagnetic field measurement device, and perform functional measurement by magnetic resonance imaging on the slice containing the position. To do.

In this embodiment, an ultrasonic transmitter / receiver is used as a means for checking the position of the marker attached to the subject.
FIG. 10 is an explanatory diagram showing an example of a marker and a marker position measuring device. The three-dimensional position of the marker is acquired by measuring the distance to the marker 35 attached to the head 36 of the subject using the ultrasonic transmitting / receiving device 34 arranged two-dimensionally. In order to measure the marker position with a measuring device using light, for example, the ultrasonic transmitting / receiving device in FIG. 10 is replaced with a laser light transmitting / receiving device, and a metal such as aluminum that reflects light as a marker or a resin coating having gloss is used. Use the object.

Although nitrogen gas was used as the gas to be injected into the fixture, it may be air, an inert gas, a liquid, or a gel. When water is used as the liquid, the water causes an artifact in magnetic resonance imaging. This problem is solved by making the T2 relaxation time of water shorter than the T2 relaxation time of biological tissue in advance.

[0030]

According to the present invention, it is possible to significantly reduce the time required for the entire measurement by mutually utilizing the function information among a plurality of function measurements. As a result, it is possible to reduce the burden on the subject and to reduce the change in the state due to the body movement of the subject. Furthermore, improvement in measurement accuracy can be expected due to a decrease in subject's state change.

The present invention also includes a fixture for fixing the subject to the measuring device and a position measuring device for the subject in order to improve the accuracy of the coordinate adjustment performed during the function measurement. With this device, it is possible to match the coordinate system of each measurement with high accuracy and to measure the position during the function measurement. As a result, in the present invention, it is possible to interrupt the functional measurement due to the movement of the subject, to warn the measurer that the measurement position is inaccurate data, and the position of the measurement data based on the position measurement result. Corrections can be made.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a biological function imaging apparatus according to the present invention.

FIG. 2 is a block diagram of a magnetic resonance imaging apparatus for implementing the present invention.

FIG. 3 is an explanatory view of a portion for fixing a subject's head in FIG.

FIG. 4 is an explanatory diagram of a brain magnetic field measuring apparatus for carrying out the present invention.

5 is an explanatory view of a portion for fixing the head of the subject in FIG. 4. FIG.

FIG. 6 is an explanatory diagram of a display example of a current dipole and a slice presented to a measurer for determining a measurement slice of a magnetic resonance imaging apparatus.

FIG. 7 shows a magnetic resonance imaging image presented to the measurer for determining the position of the detection coil of the brain magnetic field measurement apparatus and t.
Explanatory drawing of the display example of a test | inspection image and a detection coil position.

FIG. 8 is an explanatory diagram of a display example of a current dewar position and a target dewar position, which is displayed when the SQUID dewar is moved.

FIG. 9 is a flowchart showing a process of determining the position of a brain magnetic field detection coil from a magnetic resonance imaging image.

FIG. 10 is an explanatory diagram of a marker and an ultrasonic transceiver as a marker position measuring device.

[Explanation of symbols]

32 ... Biological function measuring device, 33 ... Workstation,
34 ... Ultrasonic wave transmitting / receiving device, 35 ... Marker, 36 ... Head of subject.

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Claims (4)

(57) [Claims] 1. A method for fixing a subject to a biological function measuring device.
Measures the fixed device and the position of the subject fixed on the fixture
Measuring device, presenting means for presenting a plurality of different biological function information in the same imaging region, and the biological function information
When measuring the biological function information, the position measuring device is used.
Based on the position information of the subject obtained by
An apparatus for determining a measurement position in biological function measurement, comprising an assisting unit for assisting in determining a measurement position in performance measurement . 2. The magnetic resonance imaging apparatus according to claim 1, wherein said presenting means presents a biomagnetic signal source position obtained by biomagnetic measurement , and said assisting means
An apparatus for determining a measurement position in biological function measurement that supports determination of a slice position in a magnetic resonance imaging apparatus. 3. The biomagnetic measuring apparatus according to claim 1, wherein the presenting means presents the functional information obtained by magnetic resonance imaging , and the assisting means provides the biomagnetic information.
An apparatus for determining a measurement position in biological function measurement, which assists in determining the position of a magnetic detection coil in a measurement device. 4. The method of claim 1, prior Symbol means for determining suspension and continue the determination of the movement of the subject presented in the measurer measures, biological function measurement and means for recording and storing the amount of the subject is moved Device for determining the measuring position in.