JP2011072598A - Optical coherence tomographic imaging apparatus and control method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably perform expansion of a blood vessel and indwelling treatment of a stent by applying an optical coherence tomographic imaging using OCT (Optical Coherence Tomography) and OFDI (Optical Frequency-Domain Imaging) to monitor the state of expanding a vascular wall by a balloon and the state of indwelling the stent in the vascular wall. <P>SOLUTION: In an optical coherence tomographic imaging apparatus, a probe having a transmit/receive part for continuously performing transmission and receiving of light is put in the connecting state, reflected light in a body cavity is obtained from the transmit/receive part, and a face image (or a plurality of sectional images in the axial direction) in the body cavity is generated based on the obtained reflected light. In a mounting position of the balloon expanded by injecting a fluid, the transmit/receive part is scanned to detect the state of expanding the balloon based on the received reflected light by the transmit/receive part or the sectional images obtained based on the reflected light. It is determined whether the pressurization of the balloon is stopped or not based on the detected expanding state of the blood vessel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical coherence tomography apparatus using OCT (OCT: Optical Coherent Tomography) or OFDI (Optical Frequency-Domain Imaging) and a control method thereof.

  Patent Document 1 discloses a configuration in which an optical fiber for OCT is built in a balloon catheter. According to Patent Document 1, by positioning the tip of the optical fiber in the vicinity of the inner wall of the balloon, the state of the tissue can be observed more accurately in a lumen having a relatively large diameter, such as the esophagus or the gastrointestinal tract.

  Further, as a typical use of a balloon catheter, an expandable expansion member (balloon) is disposed at a stenosis site of a blood vessel, and the stenosis site is expanded to restore a sufficient blood passage (Patent Document 2). reference). In addition, as described in Patent Document 2, it is possible to prevent restenosis in a portion where blood flow has been restored by attaching an expandable intravascular assisting device called a stent to the stenosis portion. Yes.

  In general, the stent is attached to the outer peripheral portion of the deflated balloon and is carried to the affected part (stenosis site), expanded in accordance with the expansion of the balloon, and fixed in a state where the inner wall of the blood vessel is pushed and expanded. At this time, the expansion of the stent is controlled by the size of the balloon and the pressure applied to the balloon.

US Pat. No. 6,879,851 JP-A-9-276414

  However, it is not easy to accurately grasp and control the expansion state of the balloon and the stent. If insufficient expansion occurs, the blood vessel wall is not sufficiently expanded, and the stent does not sufficiently adhere to the inner wall of the blood vessel. Can occur, and if an overdilated condition occurs, it can damage the vessel wall.

  The present invention has been made in view of the above-mentioned problems. By applying optical coherence tomographic image formation by OCT or OFDI, the expansion state of the blood vessel wall by the balloon and the indwelling state of the stent on the blood vessel wall are monitored. The purpose is to allow appropriate placement of the stent.

In order to achieve the above object, an optical interference image forming apparatus according to an aspect of the present invention comprises the following arrangement. That is,
Optical interference that connects a probe having a transmission / reception unit that continuously transmits and receives light, acquires reflected light in the body cavity from the transmission / reception unit, and generates a cross-sectional image in the body cavity based on the acquired reflected light A tomographic image forming apparatus,
A scanning control means for performing scanning by the transmission / reception unit at a mounting position of a balloon that can be inflated by fluid injection;
Based on the reflected light received by the transmission / reception unit by scanning by the scanning control unit or based on a cross-sectional image generated based on the reflected light, the expanded state of the blood vessel by the balloon is detected, and the detected blood vessel Determining means for determining whether to stop pressurizing the balloon based on the expanded state of
Output means for outputting a signal to that effect when the determination means determines that pressurization is to be stopped.

  According to the present invention, by applying optical coherence tomography, the expanded state of the blood vessel wall by the balloon and the indwelling state of the stent in the blood vessel wall are monitored, so that the expansion of the blood vessel and the indwelling treatment of the stent can be performed more appropriately. .

The figure which shows the external appearance structure of the optical coherence tomogram formation apparatus by embodiment. The block diagram which shows the function structural example of an optical coherence tomogram formation apparatus. The block diagram which shows the function structural example of the optical coherence tomographic image forming apparatus of wavelength sweep utilization. The figure which shows the structure of an optical probe. The figure which shows the structure of the front-end | tip part of an optical probe. The figure explaining the vascular expansion treatment by a stent. The flowchart explaining the pressurization control of the balloon by the profile of a stent and a blood vessel wall. The flowchart explaining the pressurization stop determination by the profile of a stent and a blood vessel wall. The flowchart explaining the pressurization stop determination by the profile of a stent and a blood vessel wall. The flowchart explaining the pressurization stop determination by the profile of a stent and a blood vessel wall. The flowchart explaining pressurization control of the balloon by reflected light intensity. The flowchart explaining pressurization control of the balloon using reference blood vessel information. The figure which shows the example of a display of a cross-sectional image.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
1. External configuration diagram of an optical coherence tomographic imaging apparatus 1 is a diagram showing an image forming apparatus (an optical interference image forming apparatus of the optical interference image forming apparatus or wavelength-sweeping) 100 external configuration of according to the embodiment.

  As illustrated in FIG. 1, the diagnostic imaging apparatus 100 includes an optical probe unit 101, a scanner / pullback unit 102, and an operation control device 103, and the scanner / pullback unit 102 and the operation control device 103 include a signal line 104. (Including an optical fiber and an electric signal line).

  The optical probe unit 101 is directly inserted into a blood vessel, and measures the state inside the blood vessel using an imaging core described later. The scanner / pullback unit 102 can be attached to and detached from the optical probe unit 101, has a built-in motor, and defines the radial operation of the imaging core in the optical probe unit 101. The operation control apparatus 103 has a function for inputting various set values and a function for processing data obtained by measurement and displaying it as a cross-sectional image when performing intravascular optical coherence tomography diagnosis. Note that the radial operation is an operation in which the moving operation of the imaging core in the axial direction of the optical probe 101 and the rotating operation with the axial direction as the rotation axis are combined.

  In the operation control device 103, reference numeral 111 denotes a main body control unit that processes data obtained by measurement and outputs a processing result. Reference numeral 111-1 denotes a printer / DVD recorder, which prints a processing result in the main body control unit 111 or stores it as data.

  Reference numeral 112 denotes an operation panel (interface), and the user inputs various setting values via the operation panel 112. Reference numeral 113 denotes an LCD monitor as a display device, which displays a processing result in the main body control unit 111.

2. Functional Configuration of Optical Interference Image Forming Apparatus Next, the main functional configuration of the optical interference image forming apparatus in the image diagnostic apparatus 100 according to the present embodiment will be described with reference to FIG.

  Reference numeral 209 denotes a low-coherence light source such as an ultra-bright light emitting diode. The low-coherence light source 209 outputs low-coherence light that exhibits coherence only in a short distance range in which the wavelength is about 1310 nm and the coherence distance (coherent length) is about several μm to several tens of μm. . Therefore, when this light is divided into two and then mixed again, the difference between the two optical path lengths from the divided point to the mixed point is within a short distance range of about several μm to several tens of μm. Is detected as interference light, and is not detected as interference light when the optical path length difference is larger than that.

  Light from the low-coherence light source 209 is incident on one end of the first single mode fiber 228 and transmitted to the distal end surface side. The first single mode fiber 228 is optically coupled to the second single mode fiber 229 and the third single mode fiber 232 at an intermediate optical coupler unit 208. The optical coupler unit is an optical component that can divide one optical signal into two or more outputs or combine two or more input optical signals into one output. The light from the coherent light source 209 can be transmitted by being divided into a maximum of three optical paths by the optical coupler unit 208.

  A scanner / pullback unit 102 is provided on the distal end side of the optical coupler unit 208 of the first single mode fiber 228. In the scanner / pullback unit 102, an optical rotary joint 203 that couples the non-rotating unit and the rotating unit and transmits light is provided. Furthermore, the distal end side of the fourth single mode fiber 230 in the optical rotary joint 203 is detachably connected to the fifth single mode fiber 231 of the optical probe unit 101 via the adapter 202. Thereby, the light from the low-coherence light source 209 is transmitted to the fifth single mode fiber 231 that is inserted into the imaging core 201 that repeatedly transmits and receives light and can be driven to rotate.

  The light transmitted to the fifth single mode fiber 231 is irradiated from the distal end side of the imaging core 201 to the living tissue in the blood vessel while performing a radial operation (radial scanning). Then, a part of the reflected light scattered on the surface or inside of the living tissue is taken in by the imaging core 201, returns to the first single mode fiber 228 side through the reverse optical path, and a part of the reflected light is reflected by the optical coupler unit 208. 2 moves to the single mode fiber 229 side. And it is radiate | emitted from the end of the 2nd single mode fiber 229, and is received by the photodetector (for example, photodiode 210).

  Note that the rotating portion side of the optical rotary joint 203 is rotationally driven by a radial scanning motor 205 of the rotational driving device 204. The rotation angle of the radial scanning motor 205 is detected by the encoder unit 206. Furthermore, the scanner / pullback unit 102 includes a linear drive device 207, and moves in the axial direction (the distal direction in the body cavity and the opposite direction) of the imaging core 201 based on an instruction from the signal processing unit 214 (axial operation). ). The axial movement is realized by the linear drive device 207 moving the scanner including the optical rotary joint 203 based on a control signal from the signal processing unit 214. At this time, the catheter sheath of the optical probe unit 101 remains fixed in the blood vessel, and only the imaging core 201 stored in the catheter sheath moves in the axial direction, so that the axial operation can be performed without damaging the blood vessel wall. Done.

  On the other hand, an optical path length variable mechanism 216 that changes the optical path length of the reference light is provided on the opposite side of the third single mode fiber 232 (reference optical path) from the optical coupler unit 208. This optical path length variable mechanism 216 replaces the optical probe unit 101 with first optical path length changing means that changes the optical path length corresponding to the examination range in the depth direction of the living tissue (the direction in which the measurement light is emitted) at high speed. And second optical path length changing means for changing the optical path length corresponding to the variation in length so as to be able to absorb variations in length of the individual optical probe sections 101 when used.

  A mirror 219 is disposed via a collimator lens 221 that is mounted on the uniaxial stage 220 together with the tip of the third single-mode fiber 232 and that is movable in the direction indicated by the arrow 223. Further, a galvanometer 217 that is rotatable through a lens 218 corresponding to the mirror 219 is attached as a first optical path length changing means. The galvanometer 217 is rotated at high speed in the direction of the arrow 222 by the galvanometer controller 224.

  The galvanometer 217 reflects light by a mirror of the galvanometer, and is configured to rotate the mirror attached to the movable part at high speed by applying an AC drive signal to the galvanometer functioning as a reference mirror. That is, a drive signal is applied from the galvanometer controller 224 to the galvanometer 217, and the optical signal is rotated in the direction of the arrow 222 at a high speed by the drive signal, so that the optical path length of the reference light is within the examination range in the depth direction of the living tissue. It will change at high speed by the corresponding optical path length. One period of the change in the optical path difference is a period for acquiring interference light for one line.

  On the other hand, when the optical probe unit 101 is replaced, the uniaxial stage 220 functions as a second optical path length changing unit having a variable range of the optical path length that can absorb variations in the optical path length of the optical probe unit 101. Further, the uniaxial stage 220 also has a function as an adjusting means for adjusting the offset. For example, even when the tip of the optical probe unit 101 is not in close contact with the surface of the living tissue, the optical path length is minutely changed by the uniaxial stage 220, thereby setting the state to interfere with the reflected light from the surface position of the living tissue. It becomes possible to do.

  The light whose optical path length is changed by the optical path length variable mechanism 216 is obtained by the optical coupler unit 208 provided at the opposite end of the third single mode fiber 232 with the light obtained from the first single mode fiber 228 side. After being mixed, the light is received by the photodiode 210 as interference light through the second single mode optical fiber 229. The interference light received by the photodiode 210 in this way is photoelectrically converted and amplified by the amplifier 211.

  Thereafter, the signal is input to the demodulator 212, and the demodulator 212 performs demodulation processing for extracting only the signal portion of the interfered light, and the output is input to the A / D converter 213. The A / D converter 213 samples the interference light signal for 200 points, for example, and generates one line of digital data (“interference light data”). In this case, the sampling frequency is a value obtained by dividing the time of one scanning of the optical path length by 200.

  The line-by-line interference light data generated by the A / D converter 213 is input to the signal processing unit 214. The signal processing unit 214 converts the interference light data in the depth direction of the living tissue into a video signal, thereby forming a cross-sectional image at each position in the blood vessel, and the LCD monitor 215 (see FIG. 1) at a predetermined frame rate. (Corresponding to number 113).

  The signal processing unit 214 is further connected to an optical path length adjusting unit control device 226. The signal processing unit 214 controls the position of the uniaxial stage 220 via the optical path length adjusting unit controller 226. The signal processing unit 214 is connected to the motor control circuit 225 and controls the rotational drive of the radial scanning motor 205. Further, the signal processing unit 214 controls the movement operation along the axial direction of the optical probe 101 in the radial operation by controlling the linear driving device 207. Even when the movement operation along the axial direction of the optical probe 101 is performed manually, the linear drive device 207 notifies the signal processing unit 214 of the movement amount. The signal processing unit 214 is connected to a galvanometer controller 224 that controls scanning of the optical path length of the reference mirror (galvanometer mirror), and the galvanometer controller 224 outputs a drive signal to the signal processing unit 214. The motor control circuit 225 synchronizes with the galvanometer controller 224 based on this drive signal. In response to a command from the signal processing unit 214, the pressurizing unit 240 supplies a fluid (gas) to the balloon 413 (described later with reference to FIG. 4) included in the catheter of this embodiment via the injection port 421 (described later with reference to FIG. 4). Or a liquid), and the balloon 413 is inflated or deflated.

3. Functional Configuration of Optical Interference Image Forming Device Using Wavelength Sweep Next, the main functional configuration of the optical interference image forming device using wavelength sweep in the image diagnostic apparatus 100 according to the present embodiment will be described with reference to FIG. FIG. 3 is a diagram showing a functional configuration of an optical interference image forming apparatus 100 using wavelength sweeping.

  Reference numeral 308 denotes a wavelength swept light source, and Swept Laser is used. A wavelength swept light source 308 using SweptLaser is a type of Extended-cavityLaser composed of an SOA 315 (semiconductor optical amplifier), an optical fiber 316 coupled in a ring shape, and a polygon scanning filter (308b). The light output from the SOA 315 travels through the optical fiber 316 and enters the polygon scanning filter 308b. The light whose wavelength is selected here is amplified by the SOA 315 and finally output from the coupler 314 (coupler).

  In the polygon scanning filter 308b, a wavelength is selected by a combination of a diffraction grating 312 for separating light and a polygon mirror 309. Specifically, the light split by the diffraction grating 312 is condensed on the surface of the polygon mirror 309 by two lenses (310, 311). As a result, only light having a wavelength orthogonal to the polygon mirror 309 returns through the same optical path and is output from the polygon scanning filter 308b. Therefore, the time sweep of the wavelength can be performed by rotating the polygon mirror 309. . As the polygon mirror 309, for example, a 32-hedron mirror is used, and the rotation speed is about 50000 rpm. The wavelength sweeping method combining the polygon mirror 309 and the diffraction grating 312 enables high-speed, high-output wavelength sweeping.

  The light of the wavelength swept light source 308 output from the coupler 314 is incident on one end of the first single mode fiber 330 and transmitted to the distal end side. The first single mode fiber 330 is optically coupled to the second single mode fiber 337 and the third single mode fiber 331 at an intermediate optical coupler unit 334. Accordingly, the light incident on the first single mode fiber 330 is divided into a maximum of three optical paths by the optical coupler unit 334 and transmitted.

  An optical rotary joint 303 that couples the non-rotating part and the rotating part and transmits light is provided on the distal end side of the optical coupler part 334 of the first single mode fiber 330. Further, the distal end side of the fourth single mode fiber 335 in the optical rotary joint 303 is detachably connected to the fifth single mode fiber 336 of the optical probe unit 101 via the adapter 302. Thereby, the light from the wavelength swept light source 308 is transmitted to the fifth single mode fiber 336 that is inserted into the imaging core 301 and can be driven to rotate.

  The transmitted light is irradiated from the distal end side of the imaging core 301 to the living tissue in the body cavity while performing radial scanning. A part of the reflected light scattered on the surface or inside of the living tissue is taken in by the imaging core 301 and returns to the first single mode fiber 330 side through the reverse optical path. Further, a part of the optical coupler unit 334 moves to the second single mode fiber 337 side, is emitted from one end of the second single mode fiber 337, and is received by a photodetector (eg, a photodiode 319).

  Note that the rotating portion side of the optical rotary joint 303 is rotationally driven by a radial scanning motor 305 of a rotational driving device 304. Further, the rotation angle of the radial scanning motor 305 is detected by the encoder unit 306. Further, the scanner / pullback unit 102 includes a linear drive device 307 and regulates the axial operation of the imaging core 301 based on an instruction from the signal processing unit 323.

  On the other hand, an optical path length variable mechanism 325 for finely adjusting the optical path length of the reference light is provided on the distal end side of the third single mode fiber 331 opposite to the optical coupler section 334. The optical path length variable mechanism 325 changes the optical path length corresponding to the variation in length so that the variation in length of each optical probe unit 101 when the optical probe unit 101 is replaced and used can be absorbed. Optical path length changing means is provided.

  A mirror 327 is disposed via a collimator lens 326 that is mounted on the uniaxial stage 332 together with the tip of the third single-mode fiber 331 and is movable in the direction indicated by the arrow 333 so as to face the tip of the third single mode fiber 331. A reference mirror 329 is attached via a lens 328 corresponding to the mirror 327. The third single mode fiber 331 and the collimating lens 326 are provided on a uniaxial stage 332 that is movable as indicated by an arrow 333 in the optical axis direction, and form optical path length changing means. Specifically, when the optical probe unit 101 is replaced, the uniaxial stage 332 functions as an optical path length changing unit having a variable range of optical path length that can absorb variations in the optical path length of the optical probe unit 101. Further, the uniaxial stage 332 also has a function as an adjusting means for adjusting the offset. For example, even when the tip of the optical probe unit 101 is not in close contact with the surface of the living tissue, the optical path length is minutely changed by the uniaxial stage, thereby setting the state to interfere with the reflected light from the surface position of the living tissue. It becomes possible.

  The light whose optical path length is finely adjusted by the variable optical path length mechanism 325 is mixed with the light obtained from the first single mode fiber 330 side by the optical coupler unit 334 provided at the end of the third single mode fiber 331. Then, the light is received by the photodiode 319 via the second single mode optical fiber 337. The interference light received by the photodiode 319 in this way is photoelectrically converted, amplified by the amplifier 320, and then input to the demodulator 321. The demodulator 321 performs demodulation processing for extracting only the signal portion of the interfered light, and its output is input to the A / D converter 322 as an interference light signal.

  The A / D converter 322 samples the interference light signal for 2048 points at 180 MHz, for example, and generates one line of digital data (interference light data). The sampling frequency of 180 MHz is based on the assumption that about 90% of the wavelength sweep cycle (12.5 μsec) is extracted as 2048 digital data when the wavelength sweep repetition frequency is 40 kHz. However, the present invention is not limited to this.

  The line-by-line interference light data generated by the A / D converter 322 is input to the signal processing unit 323. In the measurement mode, the signal processing unit 323 generates a depth direction data by frequency-resolving the interference light data by FFT (Fast Fourier Transform), and converts the cross-section at each position in the blood vessel. An image is formed and output to an LCD monitor 317 (corresponding to reference numeral 113 in FIG. 1) at a predetermined frame rate.

  The signal processing unit 323 is further connected to an optical path length adjusting unit control device 318. The signal processing unit 323 controls the position of the uniaxial stage 332 via the optical path length adjusting unit control device 318. The signal processing unit 323 is connected to the motor control circuit 324 and receives a video synchronization signal from the motor control circuit 324. The signal processing unit 323 forms a cross-sectional image in synchronization with the received video synchronization signal. The control of the linear drive device 307 and the pressurizing unit 240 by the signal processing unit 323 is as described in FIG.

  The video synchronization signal of the motor control circuit 324 is also sent to the rotation drive device 304, and the rotation drive device 304 outputs a drive signal synchronized with the video synchronization signal.

4). Configuration of optical probe unit 101
4.1 Overall Configuration of Optical Probe Unit 101 Next , the overall configuration of the optical probe unit 101 will be described with reference to FIG. The optical probe unit 101 of the present embodiment functions as a balloon catheter having an expandable balloon on the distal end side.

  As shown in FIG. 4A, the optical probe unit 101 is a long catheter sheath 401 that is inserted into a blood vessel, and is placed on the user's hand side without being inserted into the blood vessel for operation by the user. Connector 402. A guide wire lumen 403 is formed at the distal end of the sheath, and the catheter sheath 401 is formed as a continuous lumen from a connection portion with the guide wire lumen 403 to a connection portion with the connector 402. Reference numeral 404 denotes a guide wire. By moving the optical probe unit 101 along the guide wire 404, the optical probe unit 101 can reach a desired treatment site in the blood vessel. Therefore, the guide wire lumen 403 is used to receive the guide wire 404 previously inserted into the body cavity and guide the catheter sheath 401 to the affected part by the guide wire 404.

  The connector 402 includes a sheath connector 402a configured integrally with the proximal end of the catheter sheath 401, and a drive shaft connector 402b provided at the proximal end of the drive shaft and configured to rotatably hold the drive shaft. A kink protector 411 is provided at the boundary between the sheath connector 402 a and the catheter sheath 401. Thereby, a predetermined rigidity is maintained, and bending (kink) due to a rapid change can be prevented. The proximal end of the drive shaft connector 402b constitutes a part of the adapter 202 (302) that can be connected to the scanner / pullback unit 102.

  A balloon 431 that can be inflated by fluid injection is provided on the distal end side of the catheter sheath 401 and in front of the guide wire lumen 403. The balloon 431 is in communication with an infusion lumen 441 for balloon expansion shown in FIG. As the balloon 431, a balloon catheter used in a different manner can be used. However, the material used for the balloon 431 needs to transmit infrared rays, and suitable materials for the balloon 431 include, for example, silicon rubber, polyurethane, natural rubber, polyamide-polyether copolymer, polyethylene, and nylon. Polyethylene terephthalate, fluororesin, fluororubber and the like. The sheath connector 402a is provided with an injection port 421 to which a pressurizing unit 240, a syringe (not shown), or the like can be attached. The injection port 421 communicates with the balloon expansion injection lumen 441, and the balloon 431 can be inflated by injecting fluid from the injection port 421. 4C, a drive shaft 513, which will be described later with reference to FIG. 5, is inserted into the drive shaft lumen 442 so as to be slidable relative to the catheter sheath 401.

  FIG. 4B is a diagram illustrating a state in which a drive shaft 513 described later is slid relative to the catheter sheath 401. As shown in the figure, when the sheath connector 402a is fixed and the drive shaft connector 402b is slid in the proximal direction (in the direction of the arrow 451), the sheath connector 402a is fixed to the internal drive shaft 513 or its distal end. The housing 511 (FIG. 5) slides in the axial direction. This sliding in the axial direction may be performed manually by the user or electrically. A protective inner tube 452 is provided on the distal end side of the drive shaft connector 402b so that the drive shaft 513 rotating at high speed is not exposed.

4.2 Configuration of the Tip of the Optical Probe 101 Next, the configuration of the tip of the optical probe 101 will be described with reference to FIG. In FIG. 5, an imaging core 201 includes a housing 511 in which a transmission / reception unit 512 that transmits and receives measurement light is disposed inside a lumen of a catheter sheath 401 and a drive shaft 513 that transmits a driving force for rotating the housing 511. (301) is inserted substantially over the entire length, forming the optical probe portion 101.

  The transmission / reception unit 512 includes a mirror (not shown) that reflects the optical axis of the measurement light transmitted by the optical fiber inserted through the drive shaft 513 to the side. The transmission / reception unit 512 transmits measurement light toward the tissue in the body cavity and receives reflected light from the tissue in the body cavity. The drive shaft 513 is formed in a coil shape, and a signal line (single mode fiber) is disposed therein.

  The housing 511 has a shape having a notch in a part of a short cylindrical metal pipe, and is formed by cutting out from a metal lump, MIM (metal powder injection molding) or the like. The housing 511 holds the transmission / reception unit 512 inside, and the base end side is connected to the drive shaft 513. A short coil-shaped elastic member 502 is provided on the tip side. The elastic member 502 is formed by forming a stainless steel wire in a coil shape, and the elastic member 502 is arranged on the distal end side, so that stability during rotation of the imaging core 201 is improved.

  Reference numeral 501 denotes a reinforcing coil provided for the purpose of preventing sudden bending of the distal end portion of the catheter sheath 401. The drive shaft 513 can rotate and axially move with respect to the catheter sheath 401, is flexible and has a characteristic capable of transmitting rotation well, for example, a multi-layered close contact coil made of a metal wire such as stainless steel. Etc.

4). Processing of the signal processing units 214 and 323
4.1 Vascular dilation treatment using a stent First, an outline of a treatment for dilating a stenotic site in a blood vessel and maintaining the expanded state using a stent will be described. FIG. 6 is a view for explaining an expansion treatment of a stenosis site by a stent. The optical probe 401 having the expandable stent 16 attached to the outer periphery of the balloon 431 in a deflated state is advanced inside the blood vessel 10 along the guide wire 404 and fixed at the position of the stenosis site 12 to be treated. (FIG. 6A). The stent 16 is generally formed of a stretchable stainless steel lattice or mesh, and is expanded in accordance with the inflation of the balloon 431 (FIG. 6B). The expanded diameter of the stent or balloon is determined according to the inner diameter of the position where the stent is implanted (aorta, coronary artery, subiliac artery, femoral artery, subclavian artery, renal artery, carotid artery, etc.). Note that the length of the balloon 431 is somewhat longer than the length of the stent 16. The balloon 431 is inflated by supplying a fluid from the injection port 421 and pressurizing it. As shown in FIG. 6B, the stent 16 is also expanded by the expansion of the balloon 431 and hits the blood vessel wall of the blood vessel 10 to expand the stenotic region 12. In this way, the expanded stent 16 is embedded in the vessel wall of the blood vessel 10. Thereafter, the balloon 431 is deflated and extracted, so that the stent 16 remains to maintain the stenotic region 12 in the released state as shown in FIG. 6C.

4.2 Determination of Pressurization Stop by Profile of Stent and Vascular Inner Wall FIG. 7 illustrates a processing procedure of vascular dilation treatment including pressurization control of the balloon by the profile (outer shape, etc.) of the stent and balloon according to the present embodiment. It is a flowchart to do. The signal processing units 214 and 323 have a CPU (not shown), and realize a process described below by executing a program stored in a memory (not shown). In the following description, the operation of the signal processing unit 214 of the optical coherence tomographic image forming apparatus shown in FIG. 2 will be described. However, the signal processing unit 323 of the optical coherent tomographic image forming apparatus shown in FIG. Applicable.

  When the optical probe unit 101 is placed in a state as shown in FIG. 6A, the operator operates the operation panel 112 to activate the processing shown in FIG. In step S <b> 101, the signal processing unit 214 causes the pressurizing unit 240 to start injecting fluid into the balloon 431 and inflates the balloon 431. In addition, when attaching a syringe to the injection port 421 and performing pressurization manually, the process of step S101 becomes unnecessary. Next, in step S102, it is determined whether or not the lumen can be traced by auto tracing. If it is determined that the lumen can be traced, the process proceeds to step S103. Whether or not the lumen can be traced by auto-trace is determined using the difference in reflection / attenuation strength between blood and blood vessels. For example, by performing radial scanning with the optical probe unit 101 and acquiring a statistical value of the reflection intensity (for example, the sum of reflection intensity or standard deviation), it is determined whether the blood vessel wall can be observed by tracing. The In the determination of whether or not the lumen can be traced by auto tracing, it is sufficient to perform rotational scanning by the transmitting / receiving unit 512 at a fixed position in the axial direction of the optical probe unit 101. The determination may be made by measuring the reflection intensity / attenuation intensity.

  In step S103, the signal processing unit 214 causes the imaging core 201 to move while rotating the imaging core 201 in the axial direction of the optical probe 101 and rotating it about the axis (radial operation) by the rotation driving device 304 and the linear driving device 307. Radial scanning is performed by irradiating light from the front end of the substrate. In step S104, the signal processing unit 214 obtains a plurality of tomographic images at predetermined time intervals (or predetermined distance intervals) from the optical interference data obtained by radial scanning. Note that the user may set a desired value for the predetermined time interval or the predetermined distance interval. Alternatively, a specified number of tomographic images arranged at equal intervals in the axial direction of the radial scan may be obtained by specifying a desired number. Further, radial scanning in the axial direction may be performed in a range where the balloon 431 is attached.

  At this time, the obtained tomographic image may be displayed on the monitor 215. A display example in this case is shown in FIG. FIG. 13 shows a state in which tomographic images are acquired at six locations along the axial direction of the optical probe 101 and displayed on the display window 1301. The tomographic image display 1302 may be displayed by being thinned out from the tomographic image acquired in step S104. In the display example of FIG. 13, a closed region 1311 based on the position of a stent strut (hereinafter also simply referred to as a strut) detected from each tomographic image and a closed region 1312 based on the detected position of the blood vessel wall are shown. Yes. In addition, the display unit 1303 performs a display that schematically shows a tomographic image acquisition position.

  Subsequently, in step S105, the signal processing unit 214 detects the struts of the stent and the inner wall of the blood vessel from the image acquired in step S104, obtains the profiles of the strut and the inner wall of the blood vessel, and determines whether to stop pressurization. . The process of step S105 will be described later. If it is determined in step S105 that “pressurization is stopped”, the process proceeds from step S106 to step S107, and the signal processing unit 214 stops the pressurization by the pressurization unit 240 and deflates the balloon 431. When the balloon 431 is manually inflated, a notification is given to the monitor 215 or the like to stop the pressurization.

<Pressurization stop determination process (1)>
FIG. 8 is a flowchart for explaining the pressurization stop determination process in step S105. In step S201, the signal processing unit 214 selects one of a plurality of images (for example, six images in FIG. 13) acquired in step S104. In step S202, the stent strut and the blood vessel inner wall are detected from the selected image. In step S203, the signal processing unit 214 identifies a closed region based on the detected strut position. As a method for specifying the closed region, a circle or an ellipse may be specified by a well-known fitting process. Similarly, in step S204, the signal processing unit 214 specifies a closed region (for example, a circle or an ellipse) based on the detected position of the blood vessel inner wall.

  In step S205, the signal processing unit 214 obtains an area difference between the closed region specified from the strut detection position and the closed region specified from the blood vessel inner wall detection position. If the area difference is equal to or smaller than the predetermined value, the process proceeds to step S206. In step S206, the signal processing unit 214 determines whether or not the above-described area difference comparison has been completed for all of the plurality of images acquired in step S104. If there is still an unprocessed image, the process returns to step S201. If it is determined in step S206 that the above processing has been completed for all of the plurality of images, the area difference between the closed region due to the strut and the closed region due to the blood vessel inner wall is less than or equal to a predetermined value in all of the plurality of images. Become. That is, in the area where the radial scanning is performed, the profiles of the strut and the blood vessel inner wall are in good agreement, and it is determined that the stent is suitably incorporated in the blood vessel inner wall. Accordingly, the predetermined process proceeds from step S206 to step S207, and the determination result is set to “pressurization stop”, and the process proceeds to step S106.

  On the other hand, if the area difference of the closed region exceeds a predetermined value in step S205, the determination result is “continuation of pressurization” in step S208. That is, if at least one of the plurality of images acquired in step S104 has a difference in area between the closed region due to the stent and the closed region due to the inner wall of the blood vessel exceeds a predetermined value, the incorporation of the stent into the inner blood vessel wall is insufficient. Therefore, it is determined that “pressurization is continued”. An area ratio may be used instead of the area difference. In this case, the closer the ratio of the area of the closed region by the struts to the area of the closed region by the inner wall of the blood vessel is closer to 1, the more the two closed regions match. Therefore, for example, if the area ratio is between 0.9 and less than 1.0, the process branches to YES in step S205, and otherwise, the process branches to NO.

  Further, in the above processing, it is required that the determination in step S205 is a pressurization stop for all tomographic images acquired in step S104, but the present invention is not limited to this. That is, if the determination in step S205 is a pressure stop in a predetermined number (or a predetermined ratio) of tomographic images acquired in step S104, the determination in step S106 may be a pressure stop. . For example, if the determination in step S205 is a pressurization stop for four images among the six images in FIG. 13, the determination in step S106 may be a pressurization stop. Further, only tomographic images at a predetermined position among tomographic images arranged in the axial direction of the optical probe 101, for example, only tomographic images in a predetermined range on both ends may be set as determination targets. For safety, it goes without saying that the pressure may be stopped when a predetermined time elapses, when the pressure on the balloon exceeds a predetermined value, or by a user instruction or the like.

<Pressurization stop determination process (2)>
FIG. 9 is a flowchart showing another example of the pressure determination process in step S105. 9, steps that perform the same processing as in FIG. 8 are assigned the same step numbers as in FIG. In step S213, among the struts detected in step S202 in the image selected in step S201, the strut whose distance from the inner wall of the blood vessel exceeds a predetermined value is regarded as a strut floating from the inner wall of the blood vessel, and the number is counted. Then, a ratio between the number of struts determined to be floating and the total number of struts in the image is obtained (the smaller the number of struts floating relative to the total number of struts, the smaller the ratio). In step S215, the signal processing unit 214 proceeds to step S206 if the ratio calculated in step S214 is equal to or smaller than the predetermined value, and proceeds to step S208 otherwise.

  With the above processing, when the ratio calculated in step S214 is less than or equal to a predetermined value in all of the plurality of images acquired in step S104, the signal processing unit 214 determines “pressurization stop”. In addition, even in one of the plurality of images acquired in step S104, if the ratio calculated in step S214 exceeds a predetermined value, the signal processing unit 214 determines that “pressurization is continued”. As described above, if the determination in step S215 is a pressure stop in the predetermined number (or a predetermined ratio) of the tomographic images acquired in step S104, the determination in step S106 is the pressure stop. It may be. Further, only tomographic images at a predetermined position among tomographic images arranged in the axial direction of the optical probe 101, for example, only tomographic images in a predetermined range on both ends may be set as determination targets.

<Pressurization stop determination process (3)>
FIG. 10 is a flowchart showing another example of the pressure determination process in step S105. In FIG. 10, steps that perform the same processing as in FIG. 8 are given the same step numbers as in FIG. 8.

  In step S221, the signal processing unit 214 detects the positions of the strut and the blood vessel inner wall for each of the plurality of images acquired in step S104. In step S222, the signal processing unit 214 obtains the area of the closed region by the strut in each image based on the position of the strut detected in each image, and obtains the strut obtained by integrating the closed region in the axial direction of the optical probe. Find the volume (approximate value) of the closed space by. For example, the volume of the closed space is obtained by multiplying the area of the closed region in each image by the distance between the images and performing this operation for all the images acquired in step S104 and adding them. Similarly, in step S223, the signal processing unit 214 obtains the area of the closed region by the blood vessel inner wall in each image based on the position of the blood vessel inner wall detected in each image, and determines the obtained closed region in the axial direction of the optical probe. The volume (approximate value) of the closed space by the inner wall of the blood vessel obtained by integration is obtained.

  In step S224, if the difference between the volume of the closed space by the struts determined in steps S222 and S223 and the volume of the closed space by the inner wall of the blood vessel is equal to or smaller than a predetermined value, the process proceeds to step S207 and is determined to be “pressurization stop”. Is done. On the other hand, if the difference between the volume of the closed space by the struts determined in steps S222 and S223 and the volume of the closed space by the blood vessel inner wall exceeds a predetermined value, the process proceeds to step S208 and is determined to be “continuation of pressurization”. The

  In the above description, whether the “pressurization stop” or “pressurization continuation” is determined by comparing the volume difference with a predetermined value. However, the present invention is not limited to this. For example, a volume ratio may be used. In this case, the closer the ratio of the volume of the closed space by the struts to the volume of the closed space by the inner wall of the blood vessel is closer to 1, the more the two closed regions match. Therefore, for example, when the volume ratio is between 0.9 and less than 1.0, the process branches to YES in step S224, and otherwise, the process branches to NO.

4.3 Determination of Pressurization Stop by Reflection Intensity from Blood Vessel Inner Wall FIG. 11 is a flowchart for explaining an example of another processing procedure of vascular dilation treatment using a stent and a balloon according to this embodiment. The same steps as those in FIG. 7 are given the same step numbers.

  In step S121, the signal processing unit 214 acquires interference data for one round at each of a plurality of positions in the axial direction. As the plurality of positions, the positions described in step S104 in FIG. 7 can be employed. In step S122, the signal processing unit 214 selects one of the plurality of rounds of interference data acquired in step S121. In step S123, the intensity (reflection intensity) of reflected light for one round is detected from the inner wall of the blood vessel from the selected interference data. In step S124, the signal processing unit 214 statistically processes the reflection intensity obtained in step S123. For example, the total, average value, or standard deviation of the obtained reflection intensity for one round is calculated.

  In step S125, the signal processing unit 214 determines whether to continue pressurization based on the calculated statistical value. For example, when the total reflection intensity is smaller than a predetermined threshold, when the average value is smaller than the predetermined threshold, or when the standard deviation is larger than the predetermined threshold, it is determined that the pressurization is continued. And when it determines with continuing pressurization, a process returns to step S103 from step S126, and said process is repeated. On the other hand, if it is not determined to continue pressurization, the process proceeds from step S126 to step S127, and it is checked whether or not the above determination has been made for all the interference data acquired in step S121. If there is unprocessed interference data, the process returns to step S122, and the above determination is performed for other interference data. If it is determined in step S127 that processing has been completed for all interference data, it is determined that pressurization is not continued for all interference data acquired in step S121. Accordingly, the process proceeds to step S107, and the signal processing unit 214 outputs that the pressurization is stopped.

  In the above processing, the tomographic image formation and display processing is omitted, but it goes without saying that the tomographic image acquisition and display described in step S104 may be performed. Further, as described above, when the determination in step S126 is the pressurization stop in the predetermined number (or a predetermined ratio) of the interference data acquired in step S121, the pressurization stop in step S107 is executed. May be. Further, only interference data at a predetermined position, for example, interference data in a predetermined range on both ends may be determined as a determination target among the interference data for one round arranged in the axial direction of the optical probe 101.

4.4 Determination of Pressurization Stop by Comparison with Reference Blood Vessel FIG. 12 is a flowchart for explaining an example of another processing procedure for vascular dilation using a stent and a balloon according to this embodiment. The same steps as those in FIG. 7 are given the same step numbers.

  First, in step S131, reference blood vessel information is input. The reference blood vessel information is blood vessel size information before and after the stenosis site (for example, including any of the reference blood vessel diameter, major axis and minor axis, area, etc.), and may be input manually or in advance. It is also possible to measure by lumen auto-trace and hold it.

  Steps S101 to S104 are as described in FIG.

  In step S132, the signal processing unit 214 selects one of the plurality of images acquired in step S104. In step S133, the signal processing unit 214 detects the position of the blood vessel inner wall from the selected image. In step S134, the signal processing unit 214 compares the size of the reference blood vessel lumen input in step S131 with the size of the blood vessel lumen obtained from the position of the blood vessel inner wall detected in step S133. In step S135, the signal processing unit 214 returns the process to step S103 when the difference between the sizes exceeds the threshold. If the difference between the size of the lumen of the reference blood vessel and the size of the lumen derived from the inner wall of the selected image falls within the threshold, the process proceeds to step S136. In step S136, it is determined whether or not processing has been completed for all of the plurality of images acquired in step S104. If there is an unprocessed image, the process returns to step S132. The fact that there is no unprocessed image in step S136 means that the difference between the size of the lumen of the reference blood vessel and the size of the blood vessel lumen obtained from the image is within a predetermined threshold in all the images. Accordingly, the process proceeds from step S136 to step S107, and the signal processing unit 214 outputs a pressurization stop.

The size comparison in step S134 and the determination in step S135 include the following processing, for example.
A ratio between the diameter obtained by fitting the circle to the reference blood vessel and the diameter obtained by fitting the circle to the inner wall of the blood vessel detected from the selected image is obtained, and if it is within a predetermined range, S135 Branch to YES,
The ratio of the major axis and minor axis obtained by fitting the ellipse to the reference blood vessel and the major axis and minor axis obtained by fitting the ellipse to the inner wall of the blood vessel detected from the selected image are obtained, If each ratio is within the predetermined range, the process branches to YES in S135.
The difference between the area of the closed region of the reference blood vessel and the area of the closed region obtained from the inner wall of the blood vessel detected from the selected image is obtained. If the difference is equal to or smaller than the threshold value, the process branches to YES in S135.
A ratio between the area of the closed region of the reference blood vessel and the area of the closed region obtained from the inner wall of the blood vessel detected from the selected image is obtained, and if it is within the predetermined range, the process branches to YES in S135.

  As described above, the pressurization control of the balloon when implanting the stent has been described, but the present invention is not limited to this. For example, since the stent profile is not used in the processing described with reference to FIGS. 11 and 12, it can also be used for balloon pressurization control in a vascular dilation procedure without using a stent.

  In the above embodiment, the scanning is performed by rotating the probe around the axis while moving the probe in the axial direction. However, the present invention is not limited to this. For example, only the rotational scanning may be performed with the axial position of the probe fixed. As described above, when the above-described blood vessel dilating treatment is performed only by the rotational scanning of the probe, the rotational scanning is performed by fixing the position of the optical probe in the axial direction in step S103 of FIG. 7, and the fixing is performed in step S104. A tomographic image at the selected position is acquired. In the pressurization stop determination process in step S105, the process shown in FIG. 8 or 9 may be applied to the image acquired in step S104 (in this case, S201 and S206 are not necessary). Note that the determination process shown in FIG. 10 cannot be used when the axial position of the probe is fixed because changes in the axial direction are taken into consideration.

  Further, in the case where the blood vessel dilating treatment is performed only by the rotational scanning of the probe, and when the balloon pressurization control is performed by the reflected light intensity as shown in FIG. 11, the axial direction of the optical probe in step S103. Rotation scanning is performed with the position fixed, and interference data for one round at the fixed position is acquired in step S121. At this time, step S127 is unnecessary.

  Further, in the case where the blood vessel dilating treatment is performed only by the rotational scanning of the probe and the balloon pressurization control using the reference blood vessel information as shown in FIG. Rotational scanning is performed with the axial position fixed, and a tomographic image at the fixed position is acquired in step S104. Moreover, the process of step S136 becomes unnecessary. In addition, as an optical probe and a transmission / reception part, there exists a thing of the structure which transmits / receives measurement light to several radial directions simultaneously by several optical fiber, but when a probe of such a structure is used, the rotation operation at the time of scanning is also carried out. It becomes unnecessary.

  As described above in detail, according to the above embodiment, since the expansion state of the blood vessel wall by the balloon is monitored by applying optical coherence tomographic image formation by OCT or OFDI, the blood vessel expansion treatment can be performed more appropriately. In particular, the stent can be more appropriately attached to the blood vessel wall.

Claims (10)

Optical interference that connects a probe having a transmission / reception unit that continuously transmits and receives light, acquires reflected light in the body cavity from the transmission / reception unit, and generates a cross-sectional image in the body cavity based on the acquired reflected light A tomographic image forming apparatus,
A scanning control means for performing scanning by the transmission / reception unit at a mounting position of a balloon that can be inflated by fluid injection;
Based on the reflected light received by the transmission / reception unit by scanning by the scanning control unit or based on a cross-sectional image generated based on the reflected light, the expanded state of the blood vessel by the balloon is detected, and the detected blood vessel Determining means for determining whether to stop pressurizing the balloon based on the expanded state of
An optical coherence tomographic image forming apparatus comprising: output means for outputting a signal to that effect when the determination means determines that pressurization is to be stopped.   The determination means detects a position of a stent strut and a blood vessel wall mounted around the balloon in the cross-sectional image, and based on the detected positional relationship between the strut and the blood vessel wall, the balloon The optical tomographic image forming apparatus according to claim 1, wherein it is determined whether or not to stop pressurization.   In the cross-sectional image, the determination unit has a predetermined range of an area ratio between a closed region specified based on the detected position of the strut and a closed region specified based on the detected position of the blood vessel wall. 3. The optical tomographic image forming apparatus according to claim 2, wherein it is determined that the pressurization of the balloon is stopped when the area difference between the closed regions is equal to or less than a predetermined value.   The determination means obtains the number of struts floating from the blood vessel wall based on the detected position of the strut and the position of the blood vessel wall in the cross-sectional image, and the number of struts floating and the total number of struts 3. The optical tomographic image forming apparatus according to claim 2, wherein it is determined that the pressurization of the balloon is stopped when the ratio to the value is equal to or less than a predetermined value. The scanning control means performs a radial scan that moves in the axial direction of the probe while rotationally scanning the transmission / reception unit at the mounting position of the balloon,
The determination unit specifies a closed region based on the detected strut position in each of a plurality of cross-sectional images acquired by radial scanning by the scanning control unit, and based on the detected position of the blood vessel wall. The closed region is identified, and based on each identified closed region, an approximate value of the volume obtained by integrating each closed region in the axial direction is obtained, and the ratio of the approximate values of the respective volumes is within a predetermined range, or The optical tomographic image forming apparatus according to claim 2, wherein when the difference between the approximate values of the respective volumes is equal to or less than a predetermined value, it is determined that the pressurization of the balloon by the injection unit is stopped. The determination means includes
Detecting means for detecting the reflection intensity of the reflected light from the position of the blood vessel wall among the reflected light received by the transceiver unit;
When the total or average value of the reflection intensities detected by the detection means exceeds a predetermined value, or when the standard deviation value of the reflection intensity is equal to or less than a predetermined value, the pressurization of the balloon by the injection means is stopped. The optical tomographic image forming apparatus according to claim 1, wherein the determination is made. Holding means for holding information indicating the size of the lumen of the blood vessel before and after the stenosis site of the blood vessel;
In the cross-sectional image, when the ratio of the size of the closed region obtained based on the detected position of the blood vessel wall and the size indicated by the information held in the holding unit is within a predetermined range in the cross-sectional image, or The optical tom according to claim 1, wherein when the difference between the size of the closed region and the size indicated by the information is equal to or less than a predetermined value, it is determined that pressurization of the balloon by the injection unit is stopped. Image forming apparatus. An injection means for injecting a fluid into an injection path for injecting the fluid in communication with the balloon;
The light according to any one of claims 1 to 7, wherein the output means outputs a signal for stopping injection by the injection means when the determination means determines that pressurization is to be stopped. Tomographic image forming device.   The light according to any one of claims 1 to 7, wherein the output means displays that the pressurization of the balloon is stopped when the determination means determines that the pressurization is stopped. Tomographic image forming device. Optical interference that connects a probe having a transmission / reception unit that continuously transmits and receives light, acquires reflected light in the body cavity from the transmission / reception unit, and generates a cross-sectional image in the body cavity based on the acquired reflected light A method for controlling a tomographic image forming apparatus, comprising:
A scanning control step of scanning the transmitting / receiving unit at a balloon mounting position that can be inflated by fluid injection;
Based on the reflected light received by the transmission / reception unit by scanning in the scanning control step or based on the cross-sectional image generated based on the reflected light, the expanded state of the blood vessel by the balloon is detected, and the detected blood vessel A determination step of determining whether to stop pressurizing the balloon based on the expanded state of
An output step of outputting a signal to that effect when it is determined in the determination step that pressurization is to be stopped, and a method for controlling an optical coherence tomographic image forming apparatus.

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