JP2002272744A - Diagnostic imaging device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To visualize two-dimensional blood flow information and the like on the surface layer of a subject which cannot be seen with the naked eye, and make it available for diagnosis. An image capturing apparatus that captures reflected visible light or infrared light from a subject, a wavelength variable filter that can vary a transmission spectrum, and processing of an image captured by the image capturing apparatus through the wavelength variable filter are provided. An image processing unit that generates an image of an image indicating a blood flow state of the subject;
The image processing unit 3 adjusts the image obtained by adjusting the wavelength tunable filter so as to have a transmission peak at one of the reflection peak wavelengths of oxyhemoglobin in blood and a reflectance lower than the reflectance at the reflection peak wavelength. The difference from the image captured by adjusting the wavelength tunable filter so as to have a transmission peak at the indicated wavelength is calculated, and a difference image indicating the distribution state of oxyhemoglobin of the subject 6 is generated. A difference image indicating the distribution state of reduced hemoglobin is generated in the same manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image diagnostic apparatus for imaging a blood flow state or the like of a subject for use in diagnosis.

[0002]

2. Description of the Related Art Conventionally, a device using the principle of pulse oximetry has been used as an optical device for measuring the blood flow of a human body. This is to detect a change in the absorption wavelength accompanying the oxidation / reduction of hemoglobin in blood by a change in the amount of light transmitted through the subject.

[0003] For example, Japanese Patent Application Laid-Open No. 11-216133 discloses an apparatus for measuring oxygen saturation in blood at a certain point on a human body by pulse oximetry. Here, the oxygen saturation is derived from the extinction coefficients of oxyhemoglobin and reduced hemoglobin using a plurality of wavelengths of light.

[0004]

However, in recent medical care, measurement of blood flow at one location such as pulse oximetry is not sufficient as a diagnosis, and two-dimensional blood flow information in a wider range is required. Have been.

An object of the present invention is to provide a blood flow image diagnostic apparatus which visualizes two-dimensional blood flow information and the like on the surface layer of a subject which cannot be seen with the naked eye and which can be used for diagnosis.

[0006]

In order to achieve this object, the present invention is configured as follows.

(Imaging of oxygenated hemoglobin)
An imaging device that captures visible or infrared light reflected from the subject, a wavelength tunable filter that can vary the transmission spectrum, and an image captured by the imaging device via the wavelength tunable filter to process the blood flow state of the subject. An image diagnostic apparatus including an image processing unit that generates an image of an image indicating the above.

In the present invention, such an image diagnostic apparatus is imaged by adjusting the wavelength tunable filter so as to have a transmission peak at one of the reflection peak wavelengths of oxyhemoglobin in blood by the image processing unit. The difference between the image and the image captured by adjusting the wavelength tunable filter so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength is calculated, and the distribution state of oxyhemoglobin of the subject is calculated. Is generated.

Here, the reflection peak wavelength of oxyhemoglobin is in the range of 415 nm to 430 nm, 540 nm or 575 nm.

[0010] Hemoglobin in blood exists as oxidized hemoglobin in arterial flow and as reduced hemoglobin in venous flow. In our experiments, the spectral reflectance spectrum of the arm or hand is a good representation of the state of blood flow. For example, when the wrist is tied up and the blood is blocked, the amount of light reflected by the oxyhemoglobin of the hand increases, and the spectral reflectance becomes higher than before the blood ischemia.

In order to accurately capture such a blood flow state as two-dimensional image information, it is necessary to accurately extract delicate spectral information. In the present invention, by imaging an image with a reflection peak wavelength of oxyhemoglobin and a wavelength in the vicinity thereof, and by generating a difference image of both,
The distribution state of oxyhemoglobin can be known.

For example, 540 nm is selected as the reflection peak wavelength of oxyhemoglobin. First, the transmission peak wavelength of the wavelength tunable filter is adjusted to 540 nm, and imaging is performed. This image should represent the distribution of oxygenated hemoglobin.

However, since the amount of reflected light from oxyhemoglobin is weak, and the amount of reflected light by pigments such as tissues on the skin surface and melanin is also included, the distribution of oxyhemoglobin represented by the image having a transmission peak wavelength of 540 nm. It is difficult to know the flow condition.

Next, the wavelength tunable filter is adjusted to 500 nm near the reflection peak wavelength of 540 nm, and an image is taken. Since this image does not include the characteristic wavelength of oxyhemoglobin, it means that a reflected light image due to other skin tissues or pigments has been captured. Therefore, a difference value between the two images is calculated for each pixel to generate a difference image. This difference image removes the reflected light component that becomes noise due to the tissue on the skin surface or the like, becomes an image showing the distribution of oxyhemoglobin, and efficiently images the blood flow.

(Imaging of Reduced Hemoglobin) In another embodiment of the present invention, an imaging device for imaging visible or infrared light reflected from a subject, a tunable filter capable of changing a transmission spectrum, and a tunable filter are provided. By processing an image captured by the imaging apparatus, an image processing unit that generates an image of an image showing the blood flow state of the subject, the image processing unit, by the image processing unit, the reflection peak of reduced hemoglobin in blood Adjust the tunable filter so that it has a transmission peak at one of the wavelengths, and adjust the tunable filter to have a transmission peak at a wavelength that shows a lower reflectance than the reflectance at the reflection peak wavelength. And calculating a difference from the captured image to generate a difference image indicating a distribution state of reduced hemoglobin of the subject.

Here, the reflection peak wavelength of reduced hemoglobin is about 555 nm or about 660 nm.

Also in this case, the wavelength tunable filter is adjusted to, for example, 555 nm, which is the reflection peak wavelength of reduced hemoglobin, and 600 nm in the vicinity thereof to generate a differential image of each captured image, thereby obtaining a tissue image on the skin surface or the like. The reflected light component that becomes noise is removed, and an image showing the distribution of reduced hemoglobin is obtained, and the blood flow is efficiently imaged. (Imaging of oxyhemoglobin or reduced hemoglobin) The image diagnostic apparatus of the present invention broadly defines an image via a wavelength band filter having a transmission peak at one of the reflection peak wavelengths of oxyhemoglobin or reduced hemoglobin in blood. And an image capturing unit that captures an image through a wavelength band filter having a transmission peak at a wavelength indicating a reflectance lower than the reflectance at the reflection peak wavelength, and a difference between the two images captured by the image capturing unit. And an image processing unit for calculating a difference image indicating a distribution state of oxyhemoglobin or reduced hemoglobin.

Also in this case, the reflection peak wavelength of oxyhemoglobin is in the range of 415 nm to 430 nm, and about 540 nm.
m or about 575 nm, and the reflection peak wavelength of reduced hemoglobin is about 555 nm or about 660 nm.

(Imaging of Dyes in the Body) In another embodiment of the present invention, an imaging device for imaging visible or infrared light reflected from a subject, a tunable filter capable of changing a transmission spectrum, and a tunable filter are provided. An image diagnostic apparatus comprising: an image processing unit that processes an image captured by an imaging device to generate an image of an image indicating the state of the dye of the subject. Adjust the tunable filter so that it has a transmission peak at the reflection peak wavelength, and adjust the tunable filter so that it has a transmission peak at a wavelength that shows a lower reflectance than the reflectance at the reflection peak wavelength. And calculating a difference from the captured image to generate a difference image indicating a distribution state of the dye in the subject.

For example, a difference image is generated at a reflection peak of melamine, which is a factor causing a stain, and its vicinity. By focusing on the characteristic wavelength of melanin in this way, it becomes possible to acquire the distribution of the degree of deposition of melanin with higher sensitivity than an image captured by the naked eye or a general camera.

(Imaging of Injected Dye in Body) In another embodiment of the present invention, an imaging device for imaging reflected visible light or infrared light from a subject, a tunable filter capable of changing a transmission spectrum, and a tunable filter are provided. An image processing unit that generates an image of an image indicating the state of the dye injected into the subject for inspection by processing an image captured by the imaging device through the image processing apparatus. The image taken by adjusting the wavelength tunable filter so as to have a transmission peak at the reflection peak wavelength of the dye injected into the subject, and a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. It is characterized by calculating a difference from an image captured by adjusting a wavelength tunable filter so as to have a transmission peak, and generating a difference image indicating a distribution state of the dye injected into the subject. As described above, it is also possible to acquire the distribution of the dye injected into the subject for inspection with higher sensitivity than an image captured by the naked eye or a general camera.

Further, in each of the image diagnostic apparatuses of the present invention, as the wavelength variable filter, a Fabry-Perot type interference filter in which the distance between optical substrates is variable, a diffraction grating, or a filter group capable of switching a plurality of narrow band filters is used. Prepare. In particular, by using a Fabry-Perot interference filter, the distance between optical substrates can be changed by an external drive voltage, thereby changing the transmission spectrum characteristic, and the processing can be easily performed by a single imaging device.

[0023]

FIG. 1 is an explanatory view of an image diagnostic apparatus according to the present invention. In FIG. 1, the image diagnostic apparatus includes an image capturing apparatus 1 using a video camera or the like, an image processing apparatus 3 using a personal computer or the like forming an image processing unit, and a monitor 4 displaying a blood flow image.

In the lens unit 2 of the image pickup apparatus 1, a wavelength variable filter capable of changing a transmission spectrum is built. In this embodiment, a Fabry-Perot interference filter capable of changing the transmission spectrum by changing the distance between the optical substrates by switching the drive voltage is used, as will be described later.

Of course, besides the Fabry-Perot interference filter, a filter group capable of switching between a diffraction grating and a plurality of narrow band filters can be used as the wavelength variable filter. The imaging device 1 images a site such as a hand 6a and an arm 6b of the subject 6 to be diagnosed.

FIG. 2 is a block diagram of a functional configuration of the diagnostic imaging apparatus according to the present invention. In FIG. 2, the imaging apparatus 1 includes an optical system 7, a wavelength tunable filter 8, and an imaging device 9 such as a CCD. When a Fabry-Perot interference filter is used as the wavelength variable filter 8, the peak wavelength of the transmission spectrum can be varied by the drive voltage from the drive voltage source 10.

The image processing device 3 includes an MPU 11, an AD converter 12, output IFs 13 and 14, an image memory 15, and a display output IF 16. MPU of the image processing device 3
Reference numeral 11 includes a oxyhemoglobin image processing unit 24, a reduced hemoglobin image processing unit 25, an in-vivo dye image processing unit 26, and an injection dye image processing unit 27 as functions under program control.

For example, oxyhemoglobin image processing unit 2
Taking 4 as an example, the image A obtained by adjusting the wavelength tunable filter 8 so as to have a transmission peak at one of the reflection peak wavelengths of oxyhemoglobin in blood, and the reflectance at this reflection peak wavelength are smaller than those of the image A. The wavelength tunable filter 8 is adjusted so as to have a transmission peak at a wavelength showing a low reflectance, and a difference from the image B captured is calculated, and a difference image showing the distribution state of oxyhemoglobin in the diagnostic site of the subject 6 is calculated. Generate.

The reduced hemoglobin image processor 25
Shows an image A obtained by adjusting the wavelength tunable filter 8 so as to have a transmission peak at one of the reflection peak wavelengths of reduced hemoglobin in blood, and a reflectance lower than the reflectance at this reflection peak wavelength. The difference from the image B obtained by adjusting the wavelength variable filter 8 so as to have a transmission peak at the wavelength is calculated, and a difference image indicating the distribution state of reduced hemoglobin in the diagnostic site of the subject 6 is generated.

The in-vivo dye image processing unit 26 adjusts the wavelength variable filter 8 so as to have a transmission peak at the reflection peak wavelength of the in-vivo dye of the subject, for example, melanin, and obtains an image A. The wavelength tunable filter 8 is adjusted so as to have a transmission peak at a wavelength indicating a reflectance lower than the reflectance of the image B, and the difference from the image B captured is calculated.
A difference image indicating the state of distribution of the in-vivo dye at the diagnostic site of the subject 6 is generated.

Further, the injected dye image processing section 27 adjusts the wavelength tunable filter 8 so as to have a transmission peak at the reflection peak wavelength of the dye injected into the subject 6 for inspection, and an image A obtained by the adjustment. The wavelength tunable filter 8 is adjusted so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength, and a difference from the captured image B is calculated to be injected into the body of the subject. A difference image indicating the distribution state of the injected dye for inspection is generated. For each of these image processing units 24 to 27, the function of one or a plurality of processing units is selected as necessary.

FIG. 3 shows a perspective view of the internal structure of the image pickup apparatus 1 of FIG. The imaging apparatus 1 includes an objective lens 7a, a wavelength tunable filter 8, and an imaging lens 7 in a lens unit 2.
b is provided as an image sensor 9 on the main body side, for example, CC
D is provided.

FIG. 4 shows the wavelength tunable filter 8 shown in FIG. 3, which uses a Fabry-Perot interference filter. In the wavelength tunable filter 8, two glass substrates 17 and 19 are arranged in a lens frame at a predetermined distance from each other. A metal film forming a layer is deposited.

The distance between the glass substrates 17 and 19 can be varied in the micron range by an actuator using the piezoelectric element 21. The actuators using the piezoelectric elements 21 are evenly arranged at three positions on the lens frame, and the distance between the glass substrates 17 and 19 can be varied while keeping the parallel distance.

FIG. 5 shows the principle structure of a Fabry-Perot interference filter constituting the wavelength tunable filter 8 of FIG. In FIG. 5, a wavelength tunable filter 8 constituting a Fabry-Perot interference filter is provided via a piezoelectric element 21 as an actuator having a pair of glass substrates 17 and 19 on which metal films 18 and 20 such as Au are deposited. They are arranged to face each other, and a gap d1 is formed therebetween. Piezoelectric element 21
The gap d1 can be changed by receiving a DC voltage from the external drive voltage source 10.

The wavelength tunable filter 8 is formed on the glass substrate 1
The semi-transparent metal films 18 and 20 with respect to the incident light from the
Light having a plurality of types of spectra is selectively transmitted to the glass substrate 19 side in accordance with the interval d1 due to the interference effect caused by multiple reflection between them.

FIG. 6 shows the spectral characteristics of the wavelength tunable filter 8 shown in FIG. 5. The gap d1 is changed by switching the drive voltage applied from the drive voltage source 10 to the piezoelectric element 21 in two stages. Spectral characteristics can be obtained.

In the diagnostic imaging apparatus of the present invention, for example, when generating a blood flow image, attention is paid to the spectral reflection characteristics of oxyhemoglobin and reduced hemoglobin in blood, and the blood flow image is generated by utilizing the spectral reflection characteristics. Perform the conversion.

FIG. 7 shows the spectral reflection characteristics of the skin of the back of the hand as the diagnostic site in the subject 6 in FIG. Here, the solid line spectral reflection characteristic 28 is a spectral reflection characteristic in a normal state where the subject's arm is not blocked.
On the other hand, a spectral reflection characteristic 30 indicated by a broken line is a spectral reflection characteristic in a state where the subject's wrist is tied and blood is blocked. Further, as shown on the horizontal axis, this reflection spectral characteristic has a wavelength of 400 nm to 7 nm.
00mn is normalized to a spectral reflectance of 0 to 1 to represent a measurement result.

First, hemoglobin in blood exists as oxidized hemoglobin in an arterial flow, and as reduced hemoglobin in a venous flow. Here, the reflection peak wavelength in the spectral reflection characteristic of oxyhemoglobin in blood is 415 to 430 mn, 540 mn, and further 575 mn.
It is known that there is. On the other hand, it is known that the reflection peak wavelengths of reduced hemoglobin in the venous flow are at 540 to 555 mn and 660 mn.

According to the experiment of the present inventor, as shown in FIG. 7, the spectral reflection characteristics of the hand well represent the state of blood flow. That is, the spectral reflection characteristic 28 is obtained at the normal time when the wrist is not tied. However, when the wrist is tied and the blood is blocked, the spectral reflection characteristic changes as indicated by the broken line of the spectral reflection characteristic 30. However, the spectral reflectance of the spectral reflection characteristic 30 after ischemia is higher than that of the spectral reflection characteristic 28 before ischemia.

In order to capture such a change in blood flow before and after ischemia, in the present invention, taking, for example, imaging of oxyhemoglobin, one of the reflection wavelengths of oxyhemoglobin, for example, a reflection peak A wavelength of 540 mn, and a wavelength of 500 near the wavelength which hardly shows a change in reflectance due to ischemia.
mn, two images are taken, and a difference between the two is calculated to generate a difference image, and the distribution state of oxyhemoglobin can be known from the difference image.

Similarly, for reduced hemoglobin, for example, 555 mn as a reflection peak wavelength and a wavelength of 600 mn at which there is almost no change in reflectance due to ischemia at a wavelength in the vicinity thereof are selected, images at each wavelength are taken, and the two images taken are taken. The difference is calculated, and the distribution state of reduced hemoglobin can be known from the difference image.

FIGS. 8 (A) and 8 (B) show the operation of switching the drive voltage to change the transmission peak of the wavelength tunable filter 8 to λ1 = 540 mn and λ2 = 500 mn, and to calculate a difference image for obtaining a distribution state of oxyhemoglobin. It shows the correspondence with the spectral reflection characteristics when necessary images A and B are imaged.

FIG. 9 shows the functions of the image processing units 24, 25, 26 and 27 provided in the MPU 11 of FIG. As shown in FIGS. 8A and 8B, the image memory 15 is adjusted to have a transmission peak at λ1 = 540 mn, which is the reflection peak wavelength of oxyhemoglobin, for example, in the case of imaging oxyhemoglobin. The image data A captured via the wavelength tunable filter 8 and the image data B captured via the wavelength tunable filter 8 adjusted to have a transmission peak at a wavelength other than the reflection peak wavelength, for example, λ2 = 500 mn, are stored. Have been.

For the image data A and B, the difference image generator 22 calculates the difference between each pixel of the two image data A and B, and stores the difference image data DF1 in the image memory 15. The difference image data DF1 is read by the display processing unit 23 and displayed on the monitor 4.

FIGS. 8A and 8C show that the transmission voltage is switched to change the transmission peak of the wavelength tunable filter 8 to λ1 = 555 m.
n and λ2 = 600 mn, showing the correspondence between spectral reflectance characteristics when images A and B necessary to obtain a difference image of reduced hemoglobin are captured.

In this case as well, the image processing section of FIG. 9 is adjusted to have a transmission peak at λ1 = 555 mn, which is the reflection peak wavelength of reduced hemoglobin, as shown in FIGS. 8A and 8C. Image data A captured through the wavelength tunable filter 8 and image data B captured via the wavelength tunable filter 8 adjusted to have a transmission peak at a wavelength other than the reflection peak wavelength λ1, for example, λ2 = 600 mn, It is stored in the image memory 15.

With respect to the image data A and B stored in the image memory 15, the difference image generation unit 22 calculates the difference between each pixel of the two image data A and B, and obtains the difference image data D
F1 is stored in the image memory 15. The difference image data DF1 is read by the display processing unit 23, and an image of the distribution state of reduced hemoglobin is displayed on the monitor 4.

FIG. 10 shows an image diagnostic apparatus of the present invention shown in FIG.
(A) As shown in (B), λ1 = 540 mn as the reflection peak wavelength of oxyhemoglobin, and λ1
A photograph of a difference image based on an image captured by adjusting the transmission peak of the wavelength tunable filter 8 to 2 = 500 mn is shown for the back of the hand of the subject.

Here, FIG. 10A is an image in which the ischemia is started by tying the wrist, and FIG.
10 seconds, and FIG. 10C is an image 3 minutes after the ischemia.

As is apparent from the difference image showing the state of oxyhemoglobin in FIG. 10, the distribution state of oxyhemoglobin indicated by a white portion having a bright brightness because a sufficient arterial flow is obtained at the start of ischemia. Is spread all over the back of the hand, but 20 seconds after the ischemia, the bright white portion indicating oxyhemoglobin decreases as shown in FIG.
After 3 minutes in FIG. 10 (C), the distribution of oxyhemoglobin on the back of the hand disappears and only slightly remains near the base of the finger.

FIG. 11 shows an image diagnostic apparatus according to the present invention.
(A) As shown in (C), λ1 = 555 mn as the reflection peak wavelength of reduced hemoglobin, and λ2 as the wavelength in the vicinity thereof.
5 is a photograph of a difference image of the distribution state of reduced hemoglobin obtained as a difference image between two images photographed by adjusting the transmission peak of the wavelength tunable filter 8 to 600 nm.

FIG. 11A shows an image at the start of ischemia.
FIG. 11 (B) is an image 20 seconds after ischemia, and FIG. 11 (C).
Is an image 3 minutes after ischemia. At the start of ischemia in FIG. 11 (A), oxyhemoglobin is sufficiently present in the arterial flow and reduced hemoglobin in the venous flow is small, so that a white region with high brightness is not seen in the entire palm.

In FIG. 11B 20 seconds after the ischemia, the reduced hemoglobin increases due to the ischemia, and the distribution of the reduced hemoglobin indicated by a white portion with high brightness is seen over the entire palm. Fig. 11 3 minutes after ischemia
In (C), it can be seen that the distribution of reduced hemoglobin spreads from the palm to the finger.

Diagnosis of the state of blood flow using the image diagnostic apparatus of the present invention is performed, for example, as shown in FIG. 10 in addition to the temporal change in the distribution of oxyhemoglobin or reduced hemoglobin after ischemia as shown in FIGS. In addition, a change in the distribution of oxyhemoglobin, ie, a change in the distribution of the arterial flow after the ischemia is released after a predetermined time after the ischemia can provide a very interesting diagnostic result.

Of course, the distribution state of oxyhemoglobin and reduced hemoglobin can be obtained as two-dimensional image information in the same manner for an arbitrary diagnostic site as well as the hand or arm as the diagnostic site for the subject.

FIG. 12 is a photograph of a thermal image taken by a thermo camera as a comparative example for an image showing the distribution state of blood flow according to the present invention. In this thermal image, the change from the open state in FIG. 12A to the ischemic state in FIGS. 12B to 12D is shown, and a bright portion having a high luminance indicating a high temperature is the ischemia. You can see how it gradually changes. However, the presence of blood flow cannot be seen as in the images of the distribution states of oxyhemoglobin and reduced hemoglobin according to the present invention shown in FIGS. 10 and 11.

Further, in the diagnostic imaging apparatus of the present invention, the wavelength tunable filter 8 is formed so that the reflection peak wavelength of melanin, which is a pigment in the body, is λ1, and the transmission peak is obtained.
Is adjusted, the wavelength tunable filter 8 is adjusted so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at λ1, and a difference image of each obtained image is generated and displayed. The distribution of the degree of melanin deposition at the diagnostic site of the subject is compared with the conventional naked eye, general cameras, and captured images.
It can be acquired and viewed with higher sensitivity.

Further, the measurement of the distribution state of the dye in the diagnostic imaging apparatus of the present invention is not limited to the dye existing in the living body, and a difference image is similarly obtained for the dye injected from the outside for examination. You may do so.

Further, in the diagnostic imaging apparatus of the present invention, since a normal video camera can be used as the imaging device, the blood flow distribution indicating the distribution of oxyhemoglobin, reduced hemoglobin, etc. Can be obtained as a moving image showing in real time, and very interesting information necessary for diagnosis of the human body can be obtained.

The subject is not limited to the skin surface, and can be used for in-vivo observation at the time of surgery or for in-vivo diagnosis using an endoscope or the like to support surgery.

Furthermore, in the above-described embodiment, for example, the distribution state of reduced hemoglobin and the distribution state of oxyhemoglobin are separately generated and displayed. Can also. The acquired difference image is a basic black-and-white binary image. However, it is also possible to colorize the image by performing appropriate coloring according to the luminance and display it clearly.

In the above example, a diagnostic apparatus focused on a dye such as hemoglobin having a reflection peak in the visible light region has been described as an example. At this time, an infrared camera and an infrared optical band-pass filter may be used as an imaging device, and an image of a necessary wavelength band may be captured by an infrared illumination device.

In the above example, a single image pickup device adjusts the wavelength variable filter so as to have a transmission peak at one of the reflection peak wavelengths of, for example, oxyhemoglobin and reduced hemoglobin in the blood, and captures an image. Although the wavelength tunable filter is adjusted so as to have a transmission peak at a wavelength indicating a reflectance lower than the reflectance at the reflection peak wavelength, an image is captured, and the difference between the two images is calculated. A wavelength bandpass filter having a transmission peak at one of the peak wavelengths and a wavelength bandpass filter having a transmission peak at a wavelength where the reflection peak has a lower reflectance than the long wavelength reflectance are separately provided. The corresponding imaging devices may be separately provided, and the difference may be calculated from the images captured by these different imaging devices.

Further, the light from the imaging optical system may be split into two by a half mirror or the like, and each may be imaged by an imaging device through each wavelength band filter to calculate the difference.

The present invention is not limited to the above-described embodiment, but includes appropriate modifications that do not impair the objects and advantages thereof. Further, the present invention is not limited by the numerical values shown in the above embodiments.

[0068]

As described above, according to the present invention, a transmission peak is formed at one of the reflection peak wavelengths for oxyhemoglobin and reduced hemoglobin in blood, as well as for in-vivo dyes and injection dyes for examination. The image captured by adjusting the wavelength tunable filter so as to have an image captured by adjusting the wavelength tunable filter so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. By calculating the difference, it is possible to generate a difference image showing the distribution state of the oxyhemoglobin, reduced hemoglobin, in-vivo dye or the injecting dye for the test of the subject, and the skin surface of the subject, which was conventionally difficult to visualize, The two-dimensional blood flow information in the vicinity of the surface layer can be visualized and clearly displayed, and the visualized two-dimensional blood flow information allows medical information to be displayed. It is expected to obtain an effective usage information needed to treat disease diagnosis and the affected part in.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an image diagnostic apparatus according to the present invention.

FIG. 2 is a block diagram of an apparatus configuration according to the present invention.

FIG. 3 is an explanatory diagram of an imaging device used in the present invention.

FIG. 4 is an explanatory diagram of the wavelength tunable filter in FIG. 3;

5 is an explanatory diagram of the principle structure of the wavelength tunable filter in FIG.

FIG. 6 is an explanatory diagram of a spectrum transmission characteristic when the drive voltage of the tunable filter of FIG. 4 is switched.

FIG. 7 is an explanatory diagram of a spectral reflection characteristic of skin.

FIG. 8 is an explanatory diagram showing adjustment of a transmission peak of a wavelength tunable filter with respect to spectral reflection characteristics of oxyhemoglobin and reduced hemoglobin.

FIG. 9 is a functional block diagram of an image processing unit provided in the MPU of FIG. 2;

FIG. 10 is an explanatory diagram of a blood flow image of oxyhemoglobin obtained according to the present invention.

FIG. 11 is an explanatory diagram of a blood flow image of reduced hemoglobin obtained according to the present invention.

FIG. 12 is an explanatory diagram of a thermal image shown as a comparative example.

[Explanation of symbols]

 1: imaging device 2: lens unit 3: image processing device 4: monitor 7: optical system 7a: objective lens 7b: imaging lens 8: variable wavelength filter 9: imaging device (CCD) 10: drive voltage source 11: MPU 12 : A / D converter 13, 14: Output IF 15: Image memory 16: Display output IF 17, 19: Glass substrate 18, 20: Metal film 21: Piezoelectric element (actuator) 22: Difference image generation unit 23: Display processing unit

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[Procedure amendment]

[Submission date] March 30, 2001 (2001.3.3)
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

Here, the reflection peak wavelength of oxyhemoglobin is in the range of 415 nm to 430 nm , about 540 nm or
Is about 575 nm.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

First, hemoglobin in blood exists as oxidized hemoglobin in an arterial flow, and as reduced hemoglobin in a venous flow. Here reflection peak wavelength in the spectral reflection characteristics of oxyhemoglobin in the blood, 415~430mn, about 5 40mn, the further about 5 75
mn. On the other hand, the reflection peak wavelength of the reduced hemoglobin of the venous flow is approximately 5 55 mN及beauty about
It is known to be at 60 mn.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction contents]

In the above example, a single image pickup device adjusts the wavelength variable filter so as to have a transmission peak at one of the reflection peak wavelengths of, for example, oxyhemoglobin and reduced hemoglobin in the blood, and captures an image. Although the wavelength tunable filter is adjusted so as to have a transmission peak at a wavelength indicating a reflectance lower than the reflectance at the reflection peak wavelength, an image is captured, and the difference between the two images is calculated. A wavelength bandpass filter having a transmission peak at one of the peak wavelengths and a wavelength bandpass filter having a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength are separately provided, and each wavelength band filter is supported. May be separately provided, and a difference may be calculated from images captured by these different imaging devices.

Claims (9)

[Claims] An imaging device for imaging visible or infrared light reflected from a subject; a wavelength variable filter capable of varying a transmission spectrum; and processing of an image captured by the imaging device via the wavelength variable filter. An image diagnostic apparatus comprising: an image processing unit that generates an image of an image indicating a blood flow state of a subject, wherein the image processing unit sets a transmission peak at one of reflection peak wavelengths of oxyhemoglobin in blood. An image captured by adjusting the wavelength tunable filter to have an image captured by adjusting the wavelength tunable filter to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. An image diagnostic apparatus that calculates a difference from the calculated value to generate a difference image indicating a distribution state of oxyhemoglobin of the subject. 2. The image diagnostic apparatus according to claim 1, wherein the reflection peak wavelength of oxyhemoglobin is 415 nm to 43 nm.
An image diagnostic apparatus characterized by being in the range of 0 nm, about 540 nm or about 575 nm. 3. An imaging device for imaging reflected visible light or infrared light from a subject, a wavelength variable filter capable of changing a transmission spectrum, and processing of an image captured by the imaging device via the wavelength variable filter. An image diagnostic apparatus comprising: an image processing unit that generates an image of an image indicating a blood flow state of a subject, wherein the image processing unit sets a transmission peak at one of reflection peak wavelengths of reduced hemoglobin in blood. An image captured by adjusting the wavelength tunable filter to have an image captured by adjusting the wavelength tunable filter to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. And calculating a difference image indicating a distribution state of reduced hemoglobin of the subject. 4. The diagnostic imaging apparatus according to claim 3, wherein the reflection peak wavelength of reduced hemoglobin is about 555 nm or about 660 nm. 5. An image is taken through a wavelength band filter having a transmission peak at one of the reflection peak wavelengths of oxyhemoglobin or reduced hemoglobin in blood, and the reflectance is lower than the reflectance at the reflection peak wavelength. An imaging unit that captures an image via a wavelength band filter having a transmission peak at a wavelength that indicates a difference between two images captured by the imaging unit, and a difference image indicating the distribution state of oxyhemoglobin or reduced hemoglobin is calculated. An image diagnostic apparatus, comprising: an image processing unit that generates the image. 6. The diagnostic imaging apparatus according to claim 5, wherein the oxyhemoglobin has a reflection peak wavelength of 415 nm to 415 nm.
430 nm, about 540 nm or about 575 nm, and the reflection peak wavelength of the reduced hemoglobin is about 55 nm.
An image diagnostic apparatus characterized in that it is 5 nm or about 660 nm. 7. An imaging device for imaging reflected visible light or infrared light from a subject, a wavelength variable filter capable of changing a transmission spectrum, and processing of an image captured by the imaging device via the wavelength variable filter. An image diagnostic apparatus comprising: an image processing unit that generates an image of an image indicating the state of the dye in the subject, wherein the image processing unit has a transmission peak at a reflection peak wavelength of the dye in the subject. The difference between the image captured by adjusting the wavelength tunable filter and the image captured by adjusting the wavelength tunable filter so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. And calculating a difference image indicating a distribution state of the dye in the subject. 8. An imaging device for imaging reflected visible light or infrared light from a subject, a wavelength variable filter capable of varying a transmission spectrum, and processing of an image captured by the imaging device via the wavelength variable filter. An image diagnostic apparatus comprising: an image processing unit that generates an image of an image indicating a state of the dye injected into the subject for inspection; An image captured by adjusting the tunable filter so as to have a transmission peak at a reflection peak wavelength, and the tunable filter so as to have a transmission peak at a wavelength showing a reflectance lower than the reflectance at the reflection peak wavelength. An image diagnostic apparatus comprising: calculating a difference from an image captured by adjusting the difference to generate a difference image indicating a distribution state of the dye injected into the subject. 9. The image diagnostic apparatus according to claim 1, wherein the wavelength tunable filter is a Fabry-Perot interference filter having a variable distance between optical substrates, and a diffraction grating. Or a group of filters capable of switching between a plurality of narrow band filters.