JP2009098016A - Intravascular observation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intravascular observation device capable of improving visibility of a vascular wall image. <P>SOLUTION: A vascular endoscope 1 irradiates an object to be observed in the blood vessel with coherent illumination light. An imaging element 1d detects light reflected and scattered by the vascular wall and blood, and constructs an image containing a speckle component. A speckle separator 3 separates the speckle component generated by the vascular wall and the speckle component generated by the blood based on the image constructed by the imaging element 1d. An image re-constructor 4 constructs an image, in which the speckle component generated by the blood is reduced, based on the result of the separation of the speckle component by the speckle separator 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intravascular observation device for observing the inside of a blood vessel.

  In order to observe and treat an affected area (plaque etc.) in a blood vessel, an intravascular observation apparatus that visualizes the affected area in the blood vessel with an image has been developed. Blood is present in the blood vessel, and this blood interferes with observation. In order to improve the visibility of the blood vessel wall including the affected part, the following techniques have been developed.

For example, Patent Documents 1 and 2 describe a vascular ultrasonic endoscope that visualizes the inside of a blood vessel using ultrasonic waves. In particular, the vascular ultrasound endoscope described in Patent Document 1 classifies raw echo signals based on, for example, the average value of intensity and the fluctuation range, so that echoes from blood vessel walls and echoes from blood are obtained. Isolate. The vascular ultrasound endoscope described in Patent Document 2 separates a signal from a blood vessel wall and a signal from blood based on frequency characteristics obtained by Fourier transforming a series of two-dimensional intensity images.
US Pat. No. 5,520,185 US Pat. No. 6,181,810

  However, with a vascular ultrasonic endoscope, only an image with low resolution is obtained, and the visibility of the image is poor. For this reason, it is difficult to move the endoscope inserted into the blood vessel and to identify the affected part of the blood vessel wall.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an intravascular observation device that can improve the visibility of a blood vessel wall image.

  The present invention has been made in order to solve the above-described problems. Illumination means for irradiating coherent illumination light toward an observation target in a blood vessel, and light reflected and scattered by the blood vessel wall and blood A light detecting means for detecting the image, an image construction means for constructing an image including a speckle component based on the light detected by the light detection means, and a blood vessel wall based on the image constructed by the image construction means Speckle separation means for separating speckle components generated by blood and speckle components generated by blood, and reduction of speckle components generated by blood based on the result of separation of speckle components by the speckle separation means An intravascular observation device comprising image reconstruction means for constructing an image.

  In the intravascular observation device of the present invention, the speckle separation unit compares a plurality of temporally different images, calculates a movement speed or a movement distance of each region constituting the image, and The speckle component is separated based on the moving distance.

  Further, in the intravascular observation device of the present invention, the speckle separation means separates the speckle component based on the position of the speckle component in the image obtained from the result of the speckle component separation. And

  In the intravascular observation device of the present invention, optical coherence tomography (OCT) is performed.

  According to the present invention, the speckle component generated by the blood vessel wall is separated from the speckle component generated by the blood, and an image in which the speckle component generated by the blood is reduced is constructed. Visibility can be improved. In particular, by using light having a wavelength shorter than that of the ultrasonic wave, the visibility of the image of the blood vessel wall can be improved as compared with the blood vessel ultrasonic endoscope.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described. FIG. 1 shows the configuration of an intravascular observation device (vascular endoscope device) according to the present embodiment. This intravascular observation device includes a blood vessel endoscope 1 (illuminating means), a laser light source 2, a speckle separator 3 (speckle separating means), an image reconstructor 4 (image reconstructing means), and a monitor 5. ing. The vascular endoscope 1 can be inserted into a patient's body, and the rest are provided outside the patient's body.

  The blood vessel endoscope 1 constitutes a catheter that can be inserted into a blood vessel of a patient. In the blood vessel endoscope 1, the light guide 1 a guides the laser light from the laser light source 2 to the tip of the blood vessel endoscope 1 and irradiates the observation object in the blood vessel. The objective lens 1b focuses the reflected light and scattered light reflected and scattered by the blood vessel wall and blood on the image fiber 1c. The image fiber 1c guides the light imaged by the objective lens 1b to an imaging element 1d (light detection means, image construction means) provided at the end of the blood vessel endoscope 1. The imaging element 1d converts light incident from the image fiber 1c into an electrical signal by photoelectric conversion, and outputs it as an image signal. Due to the interference of reflected light and scattered light from inside the blood vessel, the image based on the image signal from the image sensor 1d becomes an image including speckled speckle components.

  The laser light source 2 emits coherent laser light (coherence light) that irradiates an observation target in a blood vessel. The speckle separator 3 separates a speckle component signal generated by the blood vessel wall and a speckle component signal generated by blood based on the image signal output from the image sensor 1d. The image reconstructor 4 constructs an image in which the speckle component generated by the blood is reduced based on the result of the speckle component separation by the speckle separator 3, so that the signal value of the speckle component generated by the blood is calculated. For example, a signal set to 0 is output to the monitor 5. The monitor 5 displays the intravascular image based on the signal from the image reconstructor 4. Since the speckle component of blood is reduced, an image with improved visibility of the blood vessel wall is displayed on the monitor 5.

  The speckle separator 3 separates speckle components as follows. The image sensor 1d captures images at a predetermined frame interval, and generates a moving image signal composed of image signals of a plurality of frames generated at different times. The speckle separator 3 compares the images based on the image signals of a plurality of frames generated at different times, and calculates the moving speed or moving distance between the frames of each region constituting the image. Since the blood vessel wall does not move, the moving speed or moving distance between the frames of the image region by the blood vessel wall is small. On the other hand, since blood moves, the moving speed or moving distance between the frames of the image area by blood is large. By calculating the moving speed or moving distance between a plurality of frames for each region and determining the magnitude relationship based on a predetermined threshold value, it is possible to distinguish between the speckle component of the blood vessel wall and the speckle component of blood. The speckle separator 3 separates the speckle component signal of the blood vessel wall and the blood speckle component signal as described above.

  As described above, according to the present embodiment, the speckle component of the blood vessel wall and the speckle component of the blood are separated based on the moving speed or moving distance between the frames of each region constituting the image, and the blood speckle component is separated. By constructing an image with reduced components, the visibility of the image of the blood vessel wall can be improved. In particular, by using light having a wavelength shorter than that of the ultrasonic wave, the visibility of the image of the blood vessel wall can be improved as compared with the blood vessel ultrasonic endoscope.

  Furthermore, according to the present embodiment, the visibility of the blood vessel wall in front of the blood vessel endoscope 1 is improved, thereby facilitating intravascular travel when the blood vessel endoscope 1 is inserted, and in the blood vessel branch path. It is possible to prevent the blood vessel endoscope 1 from being guided in the wrong direction or to accidentally damage the blood vessel by the blood vessel endoscope 1 at the blood vessel stenosis site.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In this embodiment, optical coherence tomography (OCT) is used. In OCT, light emitted from a coherence light source is divided into observation light and reference light, the observation light is reflected and scattered by an observation object, and the reference light is reflected and scattered by a reference object. When the difference between the optical path length of the observation light and the reference light is shorter than the coherence distance of the coherence light source, measurable interference occurs between the observation light and the reference light.

  FIG. 2 shows the configuration of the intravascular observation device (vascular endoscope device) according to the present embodiment. This intravascular observation apparatus includes an OCT probe 6 (illuminating means), an SLD (Super Luminescent Diode) light source 7, a distributor 8, a reference mirror 10, a photodetector 11 (light detecting means), and an image constructing device 12 (image constructing). Means), a speckle separator 13 (speckle separating means), an image reconstructor 14 (image reconstructing means), and a monitor 15. The OCT probe 6 can be inserted into the patient's body, and the rest are provided outside the patient's body.

  The OCT probe 6 constitutes a catheter that can be inserted into a blood vessel of a patient. The SLD light source 7 emits coherence light that irradiates the observation target in the blood vessel. The illumination light emitted from the SLD light source 7 is split by the two distributor 8 into observation light that travels to the observation light path 9a and reference light that travels to the reference light path 9b. The observation light that has traveled along the observation optical path 9 a is irradiated into the blood vessel by the OCT probe 6, and the observation light reflected and scattered by the blood vessel wall and blood is collected again by the OCT probe 6. The observation light collected by the OCT probe 6 returns through the observation optical path 9 a and reaches the two distributor 8.

  A reference mirror 10 that can move at high speed in the direction A in FIG. 2 is provided at the tip of the reference optical path 9b. The reference light that has traveled along the reference optical path 9 b is reflected by the reference mirror 10, returns through the reference optical path 9 b, and reaches the two distributor 8. The returned observation light and reference light interfere with each other by the two distributor 8, and the interference component is detected by the photodetector 11.

  The image constructor 12 constructs a cross-sectional image of the blood vessel based on the signal output from the photodetector 11, and outputs an image signal based on the cross-sectional image. The speckle separator 13 separates the speckle component signal generated by the blood vessel wall and the speckle component signal generated by the blood based on the image signal output from the image constructor 12. The image reconstructor 14 constructs an image in which the speckle component generated by the blood is reduced based on the result of the speckle component separation by the speckle separator 13, and thus the signal value of the speckle component generated by the blood is obtained. For example, a signal set to 0 is output to the monitor 15. The monitor 15 displays the intravascular image based on the signal from the image reconstructor 14. Since the speckle component of blood is reduced, an image with improved visibility of the blood vessel wall is displayed on the monitor 15.

  In the present embodiment, a cross-sectional image of a blood vessel can be acquired as follows by using OCT. The OCT probe 6 irradiates observation light in a direction perpendicular to the longitudinal direction (radial direction: directions B and C in FIG. 2). Further, when a mirror (not shown) rotates in the OCT probe 6, the observation light is irradiated in all radial directions so as to go around the side surface of the OCT probe 6. Since only the observation light that has returned through the optical path corresponding to the optical path length of the reference light interferes with the reference light, a specific position in the cross section of the blood vessel (constant in the B and C directions in FIG. 2 from the central axis D of the OCT probe 6). The observation light reflected and scattered at a position separated by a distance of (2) interferes with the reference light, and an interference image is obtained.

  Accordingly, when the reference mirror 10 is moved to change the optical path length of the reference light, an interference image by the observation light and the reference light reflected and scattered at different positions in the cross section of the blood vessel is obtained. A cross-sectional image of the blood vessel can be obtained from the interference image obtained corresponding to each position in the cross-section of the blood vessel. The image builder 12 synthesizes a signal corresponding to each position based on position information of the reference mirror 10 (that is, position information in the radial direction in the cross section of the blood vessel) and forms an image for one frame forming a cross section image of the blood vessel. Generate a signal. By repeating the above, image signals for a plurality of frames constituting the moving image are obtained.

  When cross-sectional images of a plurality of frames are compared, between different frames, the moving speed or moving distance of the image region due to the blood vessel wall is small, and the moving speed or moving distance of the image region due to blood is large. Therefore, the speckle separator 13 can separate the signal of the speckle component of the blood vessel wall and the signal of the speckle component of blood based on the same principle as in the first embodiment.

  The speckle separator 13 can also separate the speckle component by using the information on the generation position of the speckle component separated as described above. By performing the above processing, it becomes possible to know which portion of the blood vessel cross-sectional image is the blood vessel wall image and which portion is the blood image. Therefore, the speckle separator 13 stores the position in the image of the blood vessel wall and blood obtained by the process of separating the speckle component of the blood vessel wall and the speckle component of blood as position information of the reference mirror 10. In the subsequent processing, the speckle component of the blood vessel wall and the speckle component of blood are separated using the position information.

  For example, the speckle separator 13 determines the position of the reference mirror 10 corresponding to the position of the image area to be processed based on the relationship between each position in the cross-sectional image obtained in advance and each position of the reference mirror 10. And whether the image region to be processed is a blood vessel wall or blood is determined based on information relating the position of the reference mirror 10 and the blood vessel wall / blood flag obtained in the previous processing. . Based on the determination result, the speckle separator 13 separates the speckle component of the blood vessel wall and the speckle component of blood.

  As described above, according to the present embodiment, the visibility of the image of the blood vessel wall can be improved as in the first embodiment. Furthermore, according to the present embodiment, it is present in the blood vessel by determining whether the image region to be processed is a blood vessel wall or blood based on information associated with the blood vessel wall / blood flag. Since it is possible to grasp the position of the blood vessel wall more accurately without misidentifying a potential guide wire or forceps as a blood vessel wall, it is possible to perform intravascular movement when inserting the OCT probe 6 or surgery with forceps. It can be safe.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the above-described embodiments, and includes design changes and the like without departing from the gist of the present invention. .

It is a block diagram which shows the structure of the intravascular observation apparatus by the 1st Embodiment of this invention. It is a block diagram which shows the structure of the intravascular observation apparatus by the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vascular endoscope, 1a ... Light guide, 1b ... Objective lens, 1c ... Image fiber, 1d image sensor, 2 ... Laser light source, 3,13 ... Speckle separation 4, 14 ... image reconstructor, 5, 15 ... monitor, 6 ... OCT probe, 7 ... SLD light source, 8 ... 2 distributor, 9a ... observation optical path, 9b: Reference optical path, 10: Reference mirror, 11: Photo detector, 12: Image constructor

Claims (4)

Illuminating means for irradiating coherent illumination light toward the observation object in the blood vessel;
Light detection means for detecting light reflected and scattered by blood vessel walls and blood;
An image construction means for constructing an image including a speckle component based on the light detected by the light detection means;
Speckle separation means for separating the speckle component generated by the blood vessel wall and the speckle component generated by blood based on the image constructed by the image construction means;
Based on the result of the speckle component separation by the speckle separation means, an image reconstruction means for constructing an image with reduced speckle components generated by blood;
An intravascular observation device comprising:   The speckle separation means compares a plurality of temporally different images, calculates a movement speed or movement distance of each area constituting the image, and separates speckle components based on the movement speed or movement distance. The intravascular observation device according to claim 1.   3. The speckle separation unit separates the speckle component based on the position of the speckle component in the image obtained from the result of the speckle component separation. Intravascular observation device.   The intravascular observation apparatus according to any one of claims 1 to 3, wherein optical coherence tomography (OCT) is performed.

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