JP6669720B2 - Image diagnostic apparatus, operating method thereof, program, and computer-readable storage medium - Google Patents

Description

The present invention relates to an image diagnostic apparatus, an operation method thereof, a program, and a computer-readable storage medium.

  Endovascular treatment has been performed with high-performance catheters such as balloon catheters and stents. An image diagnostic device such as an optical coherence tomography (OCT) device or an intravascular ultrasonic diagnostic device (IVUS) is used for the diagnosis before the operation or for checking the progress after the operation. Is becoming more common. As an improved OCT, an optical coherence tomography apparatus (SS-OCT: Swept-source Optical Coherence Tomography) using a wavelength sweep has been developed. Recently, an image diagnostic apparatus combining an IVUS function and an OCT function (an image diagnostic apparatus including an ultrasonic transmitting / receiving unit capable of transmitting / receiving ultrasonic waves and an optical transmitting / receiving unit capable of transmitting / receiving light) has also been proposed. Have been.

  One of the purposes of placing a stent is to secure blood flow at a stenosis site of a blood vessel. Therefore, the diagnosis before the operation by the diagnostic apparatus is used for diagnosing the position, diameter, and length of a stenosis site of a blood vessel. Then, the dimensions and the like of the stent to be used are determined.

  Conventional stents have been made of metal such as stainless steel, but in recent years, bioresorbable stents that are made of a polymer and are absorbed by a living body have been used. However, in the case of a bioabsorbable stent, the allowable overexpansion size is smaller than that of a conventional metal stent. It is also recommended that the shape of the stent after placement be close to a circle. In order to respond to such a demand, the affected diseased blood vessel is balloon-inflated before the stent is placed, and the cross section of the lesion site is made as close as possible to a circle (Patent Document 1).

JP 2008-514303 A

  The cross-sectional view of the blood vessel lumen can be generated by the above-described diagnostic apparatus, so that it is possible to diagnose whether or not the blood vessel lumen surface has a shape deviating from a circle by looking at the cross section. . However, the diagnosis is limited to individual cross sections. In the pre-deployment diagnosis of the stent, the length of the stent to be used, the position of both ends of the stent, and the like become important. Therefore, a display format that is convenient for performing these diagnoses is desired. .

  The present invention has been made in view of such a problem, and has as its object to provide a technique for displaying the degree of circularity of a lumen surface along a blood vessel axis in an easily understandable manner.

In order to solve the above problems, for example, an image diagnostic apparatus of the present invention has the following configuration. That is,
An imaging diagnostic apparatus for acquiring an image of a blood vessel lumen, using a probe that rotatably accommodates an imaging core that emits and receives a signal and that is movable along a rotation axis,
First image generation means for generating a cross-sectional image orthogonal to the rotation axis at each position along the rotation axis based on data obtained by rotating the imaging core and moving the imaging core in the rotation axis direction When,
A second image generation unit configured to generate a cross-sectional image along a blood vessel axis based on data obtained by rotating the imaging core and moving the imaging core in a rotation axis direction;
Calculating means for calculating a circularity indicating the degree of circularity of the lumen surface in each of the cross-sectional images generated by the first image generating means;
A display unit for displaying the cross-sectional image generated by the second image generation unit and the circularity calculated by the calculation unit in association with each other.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to display visually the degree of circularity of a lumen surface along a blood-vessel axis easily.

  Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals.

The accompanying drawings are included in and constitute a part of the specification and illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the invention.
It is a figure showing the appearance composition of the diagnostic imaging device concerning this embodiment. It is a figure showing the composition of an image diagnostic device. FIG. 8 is a diagram for explaining a cross-sectional image reconstruction process. It is a figure showing the relation between the reconstructed section image, three-dimensional model data, and section information. It is a figure showing the example of the pallet used in an embodiment. FIG. 4 is a diagram illustrating an example of a GUI according to the embodiment. FIG. 4 is a diagram illustrating an example of a GUI according to the embodiment. 5 is a flowchart illustrating a processing procedure of the image diagnostic apparatus according to the embodiment.

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

[First Embodiment]
FIG. 1 is a diagram illustrating an example of an overall configuration of an image diagnostic apparatus 100 using wavelength sweep according to an embodiment of the present invention.

  The image diagnostic apparatus 100 includes a probe (or catheter) 101, a pull-back unit 102, and an operation control device 103. The pull-back unit 102 and the operation control device 103 are connected by a cable 104 via a connector 105. The cable 104 accommodates an optical fiber and various signal lines.

  The probe 101 rotatably accommodates an optical fiber. At the tip of the optical fiber, light (measurement light) transmitted from the operation control device 100 via the pullback unit 102 is transmitted in a direction substantially perpendicular to the central axis of the optical fiber, and the transmitted light is transmitted. Is provided with an imaging core 250 having an optical transmission / reception unit for receiving reflected light from outside.

  The pullback unit 102 holds an optical fiber in the probe 101 via an adapter provided in the probe 101. By driving a motor built in the pull-back unit 102 to rotate the optical fiber in the probe 101, it is possible to rotate an imaging core provided at the tip thereof. The pullback unit 102 also drives a motor provided in a built-in linear drive unit to perform a process of pulling the optical fiber in the probe 101 at a predetermined speed (this is the reason why it is called a pullback unit).

  The operation control device 103 has a function of totally controlling the operation of the diagnostic imaging device 100. The operation control device 103 has, for example, a function of inputting various setting values based on a user instruction into the device, and a function of processing data obtained by measurement and displaying the data as a tomographic image in a body cavity.

  The operation control device 103 includes a main body control unit 111, a printer / DVD recorder 111-1, an operation panel 112, an LCD monitor 113, and the like. The main body control unit 111 generates an optical tomographic image. The optical tomographic image is generated based on the interference light data while generating interference light data by causing reflected light obtained by measurement and reference light obtained by separating light from the light source to interfere with each other. Generated by processing the line data.

  The printer / DVD recorder 111-1 prints the processing result of the main body control unit 111 or stores the processing result as data. The operation panel 112 is a user interface through which a user inputs various setting values and instructions. The LCD monitor 113 functions as a display device, and displays, for example, a tomographic image generated by the main body control unit 111. Reference numeral 114 denotes a mouse as a pointing device (coordinate input device).

  Next, a functional configuration of the image diagnostic apparatus 100 will be described with reference to FIG. As described above, the image diagnostic apparatus includes the optical coherent tomographic image diagnostic apparatus (OCT) and the optical coherent tomographic image diagnostic apparatus (SS-OCT) using the wavelength sweep. The optical coherence tomography diagnostic apparatus (SS-OCT) will be described.

  In the figure, reference numeral 201 denotes a signal processing unit which controls the whole of the diagnostic imaging apparatus, and is constituted by several circuits including a microprocessor. Reference numeral 210 denotes a nonvolatile storage device represented by a hard disk, which stores various programs and data files executed by the signal processing unit 201. Reference numeral 202 denotes a memory (RAM) provided in the signal processing unit 201. Reference numeral 203 denotes a wavelength-swept light source, which repeatedly emits light having a wavelength that changes within a preset range along the time axis.

  The light output from the wavelength-swept light source 203 enters one end of the first single mode fiber 271 and is transmitted toward the distal end. The first single mode fiber 271 is optically coupled to the fourth single mode fiber 275 at an optical fiber coupler 272 on the way.

  Light emitted from the optical fiber coupler 272 in the first single mode fiber 271 to the distal end side is guided to the second single mode fiber 273 via the connector 105. The other end of the second single mode fiber 273 is connected to the optical rotary joint 230 in the pullback unit 102.

  On the other hand, the probe 101 has an adapter 101a for connecting to the pullback unit 102. Then, by connecting the probe 101 to the pull-back unit 102 by the adapter 101a, the probe 101 is stably held by the pull-back unit 102. Further, the end of the third single mode fiber 274 rotatably housed in the probe 101 is connected to the optical rotary joy 230. As a result, the second single mode fiber 273 and the third single mode fiber 274 are optically coupled. At the other end of the third single mode fiber 274 (on the leading end side of the probe 101), there is provided an imaging core 250 equipped with a lens that emits light in a direction substantially perpendicular to the rotation axis.

  As a result, the light emitted from the wavelength-swept light source 203 passes through the first single-mode fiber 271, the second single-mode fiber 273, and the third single-mode fiber 274 to the end of the third single-mode fiber 274. It is guided to the provided imaging core 250. The image core 250 emits this light in a direction perpendicular to the axis of the fiber, receives the reflected light, guides the received reflected light in reverse, and returns it to the operation control device 103.

  On the other hand, an optical path length adjusting mechanism 220 for finely adjusting the optical path length of the reference light is provided at the opposite end of the fourth single mode fiber 275 coupled to the optical fiber coupler 272. The variable optical path length mechanism 220 functions as an optical path length changing unit that changes the optical path length corresponding to the variation in the length of each probe 101 so that the variation in length can be absorbed when the probe 101 is replaced. . Therefore, a collimator lens 225 located at the end of the fourth single mode fiber 275 is provided on a movable one-axis stage 224 as indicated by an arrow 226 in the optical axis direction.

  Specifically, the single-axis stage 224 functions as an 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 probe 101 when the probe 101 is replaced. Further, the one-axis stage 224 also has a function as an adjusting means for adjusting the offset. For example, even when the tip of the probe unit 101 is not in close contact with the surface of the living tissue, the optical path length may be minutely changed by the one-axis stage so that the light interferes with the reflected light from the surface position of the living tissue. Is possible.

  The optical path length is finely adjusted by the uniaxial stage 224, and the light reflected by the mirror 223 via the grating 221 and the lens 222 is guided again to the fourth single mode fiber 275, and the first single mode fiber 275 transmits the light to the first single mode fiber 275. Is mixed with the light obtained from the single mode fiber 271 side, and is received by the photodiode 204 as interference light.

  The interference light received by the photodiode 204 in this manner is photoelectrically converted, amplified by the amplifier 205, and input to the demodulator 206. The demodulator 206 performs demodulation processing for extracting only the signal portion of the interfered light, and the output is input to the A / D converter 207 as an interference light signal.

  The A / D converter 207 samples the interference light signal at, for example, 90 MHz for 2048 points to generate one line of digital data (interference light data). The sampling frequency of 90 MHz is based on the premise that when the repetition frequency of the wavelength sweep is 40 kHz, about 90% of the wavelength sweep period (25 μsec) is extracted as 2048 points of digital data. Yes, and is not particularly limited to this.

  The interference light data for each line generated by the A / D converter 207 is input to the signal processing unit 201 and temporarily stored in the memory 202. Then, the signal processing unit 201 frequency-decomposes the interference light data by FFT (Fast Fourier Transform) to generate data (line data) in the depth direction, and performs coordinate transformation on the data to obtain data at each position in the blood vessel. An optical cross-sectional image is constructed and output to the LCD monitor 113 at a predetermined frame rate.

  The signal processing unit 201 is further connected to the optical path length adjustment driving unit 209 and the communication unit 208. The signal processing unit 201 controls the position of the one-axis stage 224 (optical path length control) via the optical path length adjusting drive unit 209.

  The communication unit 208 incorporates some driving circuits and communicates with the pull-back unit 102 under the control of the signal processing unit 201. Specifically, a drive signal is supplied to a radial scanning motor for rotating the third single mode fiber by the optical rotary joint in the pull-back unit 102, and the encoder unit 242 for detecting the rotational position of the radial motor. And supply of a drive signal to the linear drive unit 243 for pulling the third single mode fiber 274 at a predetermined speed.

  Note that the above processing in the signal processing unit 201 is also realized by executing a predetermined program by a computer.

  In the above configuration, when the probe 101 is positioned at a blood vessel position (coronary artery or the like) of a patient to be diagnosed, a transparent flush liquid (usually a physiological saline solution or a contrast medium) is released into the blood vessel from the tip of the probe by a user operation. Let it. This is to exclude the effect of blood. When the user inputs a scan start instruction, the signal processing unit 201 drives the wavelength sweep light source 203 and drives the radial scanning motor 241 and the linear driving unit 243 (hereinafter, the radial scanning motor 241 and the linear driving unit). The irradiation of light and the light receiving process by driving the H.243 are called scanning). As a result, the wavelength-swept light is supplied from the wavelength-swept light source 203 to the imaging core 250 through the above-described path. At this time, since the imaging core 250 at the distal end position of the probe 101 moves along the rotation axis while rotating, the imaging core 250 rotates and moves along the blood vessel axis. The light is emitted to the luminal surface of the blood vessel and the reflected light is received.

  Here, processing for generating one optical cross-sectional image will be briefly described with reference to FIG. FIG. 11 is a diagram for explaining a reconstruction process of a cross-sectional image of the lumen surface 301 orthogonal to the blood vessel axis of the blood vessel where the imaging core 250 is located. During one rotation (360 degrees) of the imaging core 250, transmission and reception of the measurement light are performed a plurality of times. By transmitting and receiving light once, data of one line in the direction in which the light is irradiated can be obtained. Therefore, by transmitting and receiving light 512 times during one rotation, for example, 512 pieces of interference light data extending radially from the rotation center 302 can be obtained. The 512 pieces of interference light data are subjected to fast Fourier transform to generate radial line data in a radial direction from the rotation center. The line data is dense near the rotation center position, and becomes sparser away from the rotation center position. Therefore, the pixels in the empty space of each line are generated by performing a well-known interpolation process to generate a blood vessel cross-sectional image that can be visually recognized by a human. The signal processing unit 201 performs the process of reconstructing the blood vessel cross-sectional image in this manner. At this time, the number (slice No) of each blood vessel cross-sectional image, the lumen area S of the blood vessel cross-sectional image, and the lumen area S The degree of circularity C, which is an index value indicating how close the shape is to a perfect circle, is determined.

  The algorithm for calculating the circularity C is not particularly limited. In the embodiment, for example, the ratio D2 / D1 of the major axis D1 and the minor axis D2 in the lumen area is determined as the circularity C. The maximum of D2 / D1 is 1, which is when D1 = D2. That is, in this case, the degree of circularity C can be said to be an index value that indicates that the closer the value is to 1, the closer to a perfect circle. It is very likely that a lesion site such as a stenosis is a site having a small lumen area S or a small circularity C. Hereinafter, the slice number, the lumen area S, and the circularity C (including the major axis D1 and the minor axis D2) are collectively referred to as cross-sectional feature information. Each time the signal processing unit 201 reconstructs one blood vessel cross-sectional image, the signal processing unit 201 calculates the corresponding cross-sectional feature information and stores the cross-sectional image and the cross-sectional feature information in the memory 202 in association with each other.

  The lumen area S is obtained, for example, by counting the total number of pixels on the inner side from the lumen surface toward the rotation center of the imaging core 250 and multiplying the coefficient result by a preset coefficient. The method of obtaining the cavity area may be obtained by another algorithm. The major axis D1 is the distance between the two points on the lumen surface when the distance between the two points is maximized. The minor axis D2 is defined as a distance between a perpendicular line passing through the central point of the major axis D1 and the point at which the lumen surface intersects. Also, the longest diameter and the shortest diameter passing through the center of gravity of a closed curve configured as a lumen surface may be used.

  When the processing of creating a blood vessel cross-sectional image from the start to the end of the scan is completed, the signal processing unit 201 connects the generated blood vessel cross-sectional images 401 to each other along the blood vessel axis as shown in FIG. A blood vessel image 402 can be obtained. Note that the center position of the two-dimensional blood vessel cross-sectional image coincides with the rotation center position of the imaging core 250, but is not the center position of the blood vessel cross-section. The cross-sectional image (cross-sectional image cut along a plane parallel to the blood vessel axis) of the three-dimensional blood vessel image 402 is hereinafter referred to as a vertical cross-sectional image, and cut along a plane orthogonal to the blood vessel axis in FIG. It is distinguished from a blood vessel cross-sectional image.

  In this case, the vertical cross-sectional image is generated after reconstructing the three-dimensional blood vessel image 402. However, for example, certain line data (for example, FIG. 3) used when forming a two-dimensional cross-sectional image is used. Obtaining a single line of data represented by line data of, for example, 0 °) and its inverse (180 °) is performed for all two-dimensional cross-sectional images, and by connecting them to each other, a vertical cross-sectional image is obtained. May be configured.

  In the embodiment, a stenosis part is identified by a user (doctor or the like) using the longitudinal cross-sectional image obtained as described above and cross-sectional feature information calculated when reconstructing each two-dimensional blood vessel cross-sectional image. Is displayed in an easy-to-understand manner.

  FIG. 6A shows the GUI 600 displayed on the monitor 113 at the initial stage when the scanning process is completed. As shown, the GUI 600 includes display areas indicated by reference numerals 610, 620, and 630. The display area 610 displays a vertical cross-sectional image (a blood vessel cross-sectional image cut along a plane along the blood vessel axis). In the display area 620, a stenosis index image indicating the degree of stenosis is displayed from two index values of the area S and the circularity C. The display area 630 displays a blood vessel cross-sectional image (see FIG. 3) cut along a plane perpendicular to the blood vessel axis in a line segment 612 indicated by the marker 611 displayed in the display area 610. Further, a scale 640 is displayed between the display area 610 and the display area 620 in order to facilitate the dimension in the longitudinal direction. Reference numerals 650a to 650c indicating the illustrated ranges will be described later.

  A method of generating a stenosis index image displayed on the display area 620 will be described below. As described above, when generating each blood vessel cross-sectional image, the signal processing unit 201 calculates cross-sectional feature information including the lumen area S and the circularity C for each blood vessel cross-sectional image. In this process, the signal processing unit 201 calculates the maximum lumen area Smax. Then, the lumen area S / Smax is calculated for each cross-sectional image. In other words, the maximum lumen area within the pull-back scan range is set to 1, and the area of each cross-sectional image is normalized to a range of 0 to 1. In addition, the signal processing unit 210 obtains a slice number that minimizes the circularity C.

  As shown in FIG. 5, the signal processing unit 201 includes a color palette (in the illustrated case) for two coordinate axes of the normalized lumen area S (the maximum value is 1) and the circularity C (the maximum value is also 1). Prepares 4 × 4 color palettes P00 to P33).

  Then, one palette is determined from the normalized lumen area S of each cross-sectional image and the degree of circularity C, and the color of the vertical line segment in the display area 620 is determined using the determined palette. For example, when the normalized area S of a certain blood vessel cross-sectional image is 0.74 and the circularity C is 0.52, it is determined that the palette P22 is to be used from the coordinates indicated by the two, and the palette P22 is determined. A vertical line having a color of P22 is drawn at a corresponding position in the display area 620.

  By performing the above processing, a stenosis index image to be displayed in the display area 620 of FIG. 6A is generated. Note that the part to be drawn on the determined palette is not a “vertical line” but a rectangle (rectangle). That is, when the vertical size of the display area 620 is H, its horizontal size is W, and the total number of cross-sectional images corresponding to the horizontal size is N, the area to be drawn with the determined pallet is vertical H, horizontal direction It is a rectangular area defined by W / N. Therefore, the inside of this rectangular area is filled with the determined palette color.

  The user can freely change the position of the marker 611 in the display area 610 by operating the mouse 114. When the position of the marker 611 is changed, the signal processing unit 201 reads the corresponding cross-sectional image and its cross-sectional feature information from the memory 202 based on the changed position of the marker 611, and updates the display area 630.

  Further, the signal processing unit 201 prepares two thresholds Th1 and Th2 (where Th2 <Th1) for the circularity C, and once sandwiches a point where the circularity C is reduced to less than the threshold Th2, the threshold Th1 or less. The section is determined as a lesion section, and the section is notified to the user. Reference numerals 650a, 650b, and 650c in FIG. 6A represent lesion sections.

  Further, in the embodiment, a cross-sectional image displayed in the display area 630 at an initial stage when the GUI of FIG. 6A is displayed is detected in each of a plurality of detected lesion sections, and a frame having a minimum vascular area is detected. A cross-sectional image showing the smallest blood vessel diameter was used. Then, the cross-sectional feature information (the area S before normalization, the circularity C, the major axis D1, and the minor axis D2) in the cross-sectional image having the minimum circularity C are also displayed. Further, at this time, since it is known which slice number is the slice image with the smallest circularity C, the signal processing unit 201 displays the marker 611 and the vertical line 612 at the corresponding position in the display area. Further, the cross-sectional image displayed in the display area 630 in the initial stage of FIG. 6A may be a cross-sectional image with the smallest circularity.

  The processing procedure of the signal processing unit 201 will now be described with reference to the flowchart of FIG. In the following description, it is assumed that the probe 101 has already been inserted into a target blood vessel affected part of a patient.

  First, in step S101, it is determined whether an instruction to start scanning has been given from the operation panel 112. If it is determined that a scan start instruction has been issued, the process proceeds to step S102, and a pull-back scan process is performed. In this pull-back scan process, the signal processing unit 201 causes the pull-back unit 102 to rotate the imaging core 250 at a preset speed via the communication unit 208 and perform a process of moving the imaging core 250 backward at a predetermined speed. As a result, interference light data in which the measurement light and the reference light are multiplexed is obtained, and a process of storing the data in the memory 202 is performed. Then, in step S103, it is determined whether or not the amount of movement of the imaging core 250 with respect to the blood vessel axis has reached the planned amount of movement. If not, the pull-back scan is continued.

  Next, when the imaging core 250 has been moved by the planned distance, the process proceeds to step 104, where the interference light data stored in the memory 202 is subjected to FFT (fast Fourier transform), frequency-resolved, and (Line data) is generated, and a reconstruction process of a cross-sectional image orthogonal to the blood vessel axis is performed using the result. In step S105, cross-sectional feature information (lumen area S, major axis D1, minor axis D2, and circularity C) for the reconstructed cross-sectional image is calculated, and the cross-sectional image and cross-sectional characteristic information are associated with each other and stored in the memory. 202. Then, in step S106, it is determined whether or not the reconstruction processing of all cross-sectional images has been completed, and if not, the processing of steps 104 and 105 is repeated.

  When the reconstruction processing of all cross-sectional images is completed, the process proceeds to step 107, and a pallet for indicating a stenosis index for each cross-sectional image is determined based on the image feature information of each cross-sectional image. At this time, in the range where the pull-back scan was performed, as described above, a section having a circularity smaller than the threshold Th2 and sandwiching the point equal to or smaller than the threshold Th1 is determined as a lesion section, and the minimum lumen in each lesion section is determined. Find the area. Then, in step S108, a longitudinal section image cut by a plane parallel to the blood vessel axis (an arrow indicating a lesion section is also synthesized), a stenosis index image determined by a palette of each section image, and each obtained lesion section Are compared, a tomographic image showing the minimum area is displayed in a layout as shown in FIG. 6A, and a marker 611 and a line segment 612 are drawn movably at the displayed cross-sectional image position.

  As a result, as shown in FIG. 6A, it is possible to provide a GUI that can easily grasp how the lesion site exists along the blood vessel axis in consideration of the lumen area and the circularity. . Further, even if no operation is performed, a section expected to be a lesion is displayed according to the degree of circularity, and a minimum lumen area in each section is obtained. Further, a cross-sectional image having a minimum lumen area between the sections is obtained. Since it is displayed and the lumen area and the circularity at that position are displayed, it is also possible to easily determine where the region to be included when placing the stent should be. In addition, it is desired that both ends of the stent at the time of placing the stent be healthy blood vessels, that is, portions having a circularity close to a perfect circle and a large area. In this regard, as a result of the display of FIG. 6A, it is possible to easily understand the position where both the lumen area and the circularity are high, and it is also possible to easily know the length by comparing it with the scale.

  In addition, a marker is displayed at the position where the degree of circularity in the fixed section outside the obtained lesion section is the maximum (there are two at both ends of the section), and when the marker is designated by the user, the corresponding marker is displayed. A cross-sectional image to be displayed may be displayed in the display area 630. Usually, this is because it is desired that the positions of both ends of the stent when placing the stent be healthy blood vessel positions (positions with a large circularity).

  In the case of FIG. 6A, one pallet to be used is determined based on two index values of the lumen area and the circularity. In other words, since one pallet represents the lumen area S and the circularity C, the user needs to be familiar with the relationship. In order to further facilitate the understanding, for example, the GUI of FIG. 6B may be used instead of FIG. 6A. In FIG. 6B, since the display area 622 for displaying the index of the circularity and the display area 623 for displaying the index of the lumen area are displayed independently, only the brightness (or density) is high and low for the user. And the degree of understanding can be easily understood.

  Also, in FIGS. 6A and 6B, the circularity and the lumen area are indicated by pallets and shades to indicate the magnitude of the lumen area. However, since the circularity and the lumen area are both already calculated as numerical values, they are represented by line graphs and the like. No problem.

  In addition, the maximum value, minimum value, and average value of the lumen area, major axis, minor axis, and circularity in each lesion section, respectively. The section length may be displayed together.

  A blood vessel to be diagnosed may have a branch. In some cases, the degree of circularity cannot be measured at such a branched portion. Therefore, the branch portion may be excluded from the calculation target of the circularity.

  Further, in the above-described embodiment, the condition that the probe is inserted into the blood vessel of the patient and scanning is performed by the time the GUI of FIGS. 6A and 6B is displayed is used, but the data obtained by scanning is stored in a storage medium such as a hard disk. 6A and 6B may be read from the storage medium at a later time and the GUIs of FIGS. 6A and 6B may be displayed. In this case, after the data stored in the storage medium is read out to the memory 202, the processes after S104 in FIG. 7 are performed.

  The embodiment has been described above. In the present embodiment, an example in which the present invention is applied to an image diagnostic apparatus (SS-OCT) based on optical interference using wavelength sweeping has been described. However, even an apparatus using an ultrasonic wave (IVUS) can reconstruct a blood vessel cross-sectional image and a 3D blood vessel image, and thus may be applied to such an apparatus. Further, the present invention can be applied to an apparatus using both IVUS and OCT.

  As can be seen from the above embodiment, a part of the characteristic portion in the embodiment is at least a signal processing unit 201 including a microprocessor. The microprocessor realizes its function by executing a program, and therefore, the program naturally falls within the scope of the present invention. Usually, the program is stored in a computer-readable storage medium such as a CD-ROM or a DVD-ROM, and is set in a reading device (a CD-ROM drive or the like) of the computer and copied or installed in the system. It is clear that such a computer-readable storage medium also falls within the scope of the present invention.

  The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, to make the scope of the present invention public, the following claims are appended.

  This application claims the priority based on Japanese Patent Application No. 2015-035598 filed on Feb. 25, 2015, the entire contents of which are incorporated herein by reference.

Claims (12)

An imaging diagnostic apparatus for acquiring an image of a blood vessel lumen, using a probe that rotatably accommodates an imaging core that emits and receives a signal and that is movable along a rotation axis,
First image generation means for generating a cross-sectional image orthogonal to the rotation axis at each position along the rotation axis based on data obtained by rotating the imaging core and moving the imaging core in the rotation axis direction When,
A second image generation unit configured to generate a cross-sectional image along a blood vessel axis based on data obtained by rotating the imaging core and moving the imaging core in a rotation axis direction;
Calculating means for calculating a circularity indicating the degree of circularity of the lumen surface in each of the cross-sectional images generated by the first image generating means;
An image diagnostic apparatus, comprising: display means for displaying the cross-sectional image generated by the second image generating means and the circularity calculated by the calculating means in association with each other. The calculating means further calculates a lumen area in each cross-sectional image generated by the first image generating means,
2. The diagnostic imaging apparatus according to claim 1, wherein the display unit displays an image indicating the size of the calculated lumen area in parallel with the cross-sectional image. 3.   The image according to claim 2, wherein the display unit determines a color palette to be used based on the two values of the circularity and the lumen area, and displays an image represented by the determined color palette. Diagnostic device. In the cross-sectional image generated by the first image generating means, further includes a specifying means for specifying a cross-sectional image having the smallest circularity,
The display means displays a preset mark at a position corresponding to the cross-sectional image specified by the specifying means on the cross-sectional image generated by the second image generating means, and sets the circularity to be minimum. The image diagnostic apparatus according to any one of claims 1 to 3, wherein a cross-sectional image is displayed. The circularity calculated by the calculating means is compared with a first threshold value and a second threshold value (where first threshold value <second threshold value), and a cross-sectional image having a circularity less than the first threshold value is sandwiched. Further having a lesion section detecting means for detecting a section sandwiched between both ends as a lesion section as follows,
The image diagnostic apparatus according to claim 1, wherein the display unit displays an image indicating the lesion section. In-section identification means for identifying a cross-sectional image indicating the minimum lumen area in the section, detected by the lesion section detection means, in a single or a plurality of lesion sections,
Comparing the minimum lumen area in each lesion section determined using the intra-section specifying means with each other, further comprising an inter-section specifying means for specifying a cross-sectional image with the smallest lumen area,
The display means displays a preset mark at a position corresponding to the cross-sectional image specified by the interval specifying means on the cross-sectional image generated by the second image generating means, and the circularity is The image diagnostic apparatus according to claim 5, wherein a minimum cross-sectional image is displayed. The lumen area in the cross-sectional image included in the lesion section, the maximum value of each circularity, the minimum value, further comprising means for calculating the average value,
The image diagnostic apparatus according to claim 5, wherein the display unit displays a lumen area, a maximum value, a minimum value, an average value, and a section length of each of the lesion sections.   The image processing apparatus further includes an out-of-segment identification unit that identifies a tomographic image in which a circularity in a certain section outside the lesion section detected by the lesion section detection unit is closest to a perfect circle. A mark set in advance is displayed at a position corresponding to the cross-sectional image specified by the specifying means, and the lumen area of the relevant cross-sectional image, the circularity, the maximum value, the minimum value, and the average value are displayed. The image diagnostic apparatus according to any one of claims 5 to 7.   2. The display device according to claim 1, wherein the display unit displays a scale indicating a dimension in parallel with the cross-sectional image generated by the second image generating unit and an image indicating the circularity calculated by the calculating unit. An image diagnostic apparatus according to any one of claims 1 to 8. A method for operating an image diagnostic apparatus for acquiring an image of a blood vessel lumen, using a probe that rotatably accommodates an imaging core that emits and receives a signal and that is movable along a rotation axis,
First image generating means , based on data obtained by rotating the imaging core and moving the imaging core in the direction of the rotation axis, generates a cross-sectional image orthogonal to the rotation axis at each position along the rotation axis. A first image generating step of generating;
A second image generation step of generating a cross-sectional image along a blood vessel axis based on data obtained by rotating the imaging core and moving the imaging core in a rotation axis direction;
Calculating means, a calculating step of calculating the circularity showing a circular degree of luminal surface in each cross-sectional image generated by the first image generation step,
Display means, wherein the cross-sectional image generated by the second image generation step, a method of operating an image diagnostic apparatus characterized by comprising a display step of displaying in association with the circularity calculated by the calculating step.   A program for causing a computer to function as the image diagnostic apparatus according to any one of claims 1 to 9 when read and executed by the computer.   A computer-readable storage medium storing the program according to claim 11.