JP2018000776A - X-ray diagnostic apparatus and image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray diagnostic apparatus capable of improving efficiency of a technique using an angiogram and an image processor.SOLUTION: The X-ray diagnostic apparatus has a collection part, an identification part and a display control part. The collection part collects a plurality of X-ray images with time on the basis of X-rays transmitting through a subject to whom a contrast media is injected. The identification part identifies a blood vessel area in a blood flow direction from a prescribed position in a blood vessel area on the basis of a transition of a signal strength of the contrast media with time per unit area comprising a pixel or a plurality of pixels in blood vessel areas of the plurality of X-ray images. The display control part causes a display image expressing the blood vessel area identified by the identification part to be displayed in a display manner different from vessel blood areas other than that blood vessel area.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an X-ray diagnostic apparatus and an image processing apparatus.

  Conventionally, a guide function by an X-ray diagnostic apparatus for operating a device such as a catheter or a guide wire in a blood vessel in interventional treatment is known. For example, an X-ray diagnostic apparatus collects an X-ray image (blood vessel image) representing a blood vessel using a contrast agent, masks the blood vessel image on a fluoroscopic image, and displays it by a road map function. Support device operation. According to the road map function, the operator can advance the device to the target position while referring to the shape of the blood vessel in which the device is inserted.

Japanese Unexamined Patent Publication No. 2011-139821 JP 2014-039863 A JP 2015-217170 A JP-T-2006-501096

  The problem to be solved by the present invention is to provide an X-ray diagnostic apparatus and an image processing apparatus capable of improving the efficiency of a procedure using a blood vessel image.

  The X-ray diagnostic apparatus according to the embodiment includes a collection unit, a specifying unit, and a display control unit. The collection unit collects a plurality of X-ray images over time based on the X-rays transmitted through the subject into which the contrast agent has been injected. The specifying unit is configured to determine a blood flow direction from a predetermined position in the blood vessel region based on a temporal transition of the signal strength of the contrast agent for each unit region including one or a plurality of pixels in the blood vessel region of the plurality of X-ray images. Identify the blood vessel region. The display control unit displays a display image representing the blood vessel region specified by the specifying unit in a display mode different from the blood vessel region other than the blood vessel region.

FIG. 1 is a block diagram showing an example of the configuration of the X-ray diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram for explaining a perspective road map. FIG. 3A is a diagram for explaining the PI road map. FIG. 3B is a diagram for explaining the PI road map. FIG. 4 is a diagram illustrating an example of determination of a predetermined position according to the first embodiment. FIG. 5A is a diagram illustrating an example of specifying a blood vessel region in a blood flow direction according to the first embodiment. FIG. 5B is a diagram showing an example of specifying a blood vessel region in the blood flow direction according to the first embodiment. FIG. 5C is a diagram showing an example of specifying the blood vessel region in the blood flow direction according to the first embodiment. FIG. 5D is a diagram illustrating an example of specifying a blood vessel region in the blood flow direction according to the first embodiment. FIG. 6A is a diagram illustrating an example of specifying the blood vessel region in the blood flow direction at the intersection according to the first embodiment. FIG. 6B is a diagram illustrating an example of specifying the blood vessel region in the blood flow direction at the intersection according to the first embodiment. FIG. 6C is a diagram illustrating an example of specifying the blood vessel region in the blood flow direction at the intersection according to the first embodiment. FIG. 7 is a diagram illustrating an example of a display image according to the first embodiment. FIG. 8A is a diagram illustrating an example of a display image according to the first embodiment. FIG. 8B is a diagram illustrating an example of a display image according to the first embodiment. FIG. 9A is a diagram illustrating an example of a display image according to the first embodiment. FIG. 9B is a diagram illustrating an example of a display image according to the first embodiment. FIG. 10 is a flowchart for explaining a series of processing steps of the X-ray diagnostic apparatus according to the first embodiment.

  Hereinafter, an X-ray diagnostic apparatus according to an embodiment will be described with reference to the drawings.

(First embodiment)
First, an example of the configuration of the X-ray diagnostic apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing an example of the configuration of the X-ray diagnostic apparatus 100 according to the first embodiment. As shown in FIG. 1, the X-ray diagnostic apparatus 100 according to the first embodiment includes a high voltage generator 11, an X-ray tube 12, a collimator 13, a top plate 14, a C arm 15, and an X-ray. And a detector 16. Further, the X-ray diagnostic apparatus 100 according to the first embodiment includes a C-arm rotation / movement mechanism 17, a top board movement mechanism 18, a C-arm / top board mechanism control circuit 19, an aperture control circuit 20, and a process. A circuit 21, an input circuit 22, and a display 23 are provided. The X-ray diagnostic apparatus 100 according to the first embodiment includes an image data generation circuit 24, a storage circuit 25, and an image processing circuit 26. In addition, the X-ray diagnostic apparatus 100 is connected to the injector 30. In the X-ray diagnostic apparatus 100, as shown in FIG. 1, the circuits are connected to each other, and various electrical signals are transmitted and received between the circuits, and electrical signals are transmitted to and received from the injector 30.

  The injector 30 is a device for injecting a contrast medium from a catheter inserted into the subject P. Here, the contrast agent injection from the injector 30 is executed in accordance with the injection instruction received via the processing circuit 21 described later. Specifically, the injector 30 executes contrast agent injection in accordance with contrast agent injection conditions including an injection start instruction, an injection stop instruction, and an injection speed received from the processing circuit 21 described later. The injector 30 can also start and stop injection according to an injection instruction directly input to the injector 30 by the operator.

  In the X-ray diagnostic apparatus 100 shown in FIG. 1, each processing function is stored in the storage circuit 25 in the form of a program that can be executed by a computer. The C arm / top plate mechanism control circuit 19, aperture control circuit 20, processing circuit 21, image data generation circuit 24 and image processing circuit 26 have functions corresponding to each program by reading the program from the storage circuit 25 and executing it. This is a processor to be realized. In other words, each circuit that has read each program has a function corresponding to the read program.

  The term “processor” used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), or a programmable logic device ( For example, it means circuits such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). The processor implements a function by reading and executing a program stored in the storage circuit 25. Instead of storing the program in the storage circuit 25, the program may be directly incorporated into the processor circuit. In this case, the processor realizes the function by reading and executing the program incorporated in the circuit. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining a plurality of independent circuits to realize the function. Good.

  The high voltage generator 11 generates a high voltage under the control of the processing circuit 21 and supplies the generated high voltage to the X-ray tube 12. The X-ray tube 12 generates X-rays using the high voltage supplied from the high voltage generator 11. The collimator 13 narrows the X-rays generated by the X-ray tube 12 under the control of the diaphragm control circuit 20 so that the region of interest of the subject P is selectively irradiated. For example, the collimator 13 has four slidable diaphragm blades. The collimator 13 slides these diaphragm blades under the control of the diaphragm control circuit 20 to narrow down the X-rays generated by the X-ray tube 12 and irradiate the subject P.

  The top 14 is a bed on which the subject P is placed, and is placed on a bed (not shown). The X-ray detector 16 detects X-rays that have passed through the subject P. For example, the X-ray detector 16 has detection elements arranged in a matrix. Each detection element converts the X-rays that have passed through the subject P into electrical signals and stores them, and transmits the stored electrical signals to the image data generation circuit 24.

  The C arm 15 holds the X-ray tube 12, the collimator 13, and the X-ray detector 16. The X-ray tube 12 and the collimator 13 and the X-ray detector 16 are arranged so as to face each other with the subject P sandwiched by the C arm 15. In FIG. 1, the case where the X-ray diagnostic apparatus 100 is a single plane has been described as an example, but the embodiment is not limited to this and may be a biplane.

  The C-arm rotating / moving mechanism 17 is a mechanism for rotating and moving the C-arm 15, and the top board moving mechanism 18 is a mechanism for moving the top board 14. The C arm / top plate mechanism control circuit 19 controls the C arm rotation / movement mechanism 17 and the top plate movement mechanism 18 under the control of the processing circuit 21, thereby rotating and moving the C arm 15 and the top plate 14. Adjust the movement. The aperture control circuit 20 controls the irradiation range of the X-rays irradiated to the subject P by adjusting the aperture of the aperture blades of the collimator 13 under the control of the processing circuit 21.

  The image data generation circuit 24 generates image data using the electrical signal converted from the X-rays by the X-ray detector 16. For example, the image data generation circuit 24 performs current / voltage conversion, A (Analog) / D (Digital) conversion, and parallel / serial conversion on the electrical signal received from the X-ray detector 16 to generate image data (projection). Data). For example, the image data generation circuit 24 generates image data captured in a state where no contrast medium is injected and image data (blood vessel data) captured in a state where a contrast medium is injected. For example, the image data generation circuit 24 generates image data for fluoroscopy. The image data generation circuit 24 stores the generated image data in the storage circuit 25.

  The storage circuit 25 receives and stores the image data generated by the image data generation circuit 24. The storage circuit 25 stores programs corresponding to various functions that are read and executed by each circuit shown in FIG. For example, the storage circuit 25 stores a program corresponding to the collection function 211 read and executed by the processing circuit 21, a program corresponding to the specific function 212, and a program corresponding to the display control function 213.

  The image processing circuit 26 performs various image processing on the image data stored in the storage circuit 25 to generate an X-ray image and stores the X-ray image in the storage circuit 25. For example, the image processing circuit 26 reads out image data captured in a state where no contrast medium is injected and image data captured in a state where the contrast medium is injected from the storage circuit 25 and performs subtraction (Log sub). Then, a difference image is generated by performing various types of image processing on the subtracted data. The difference image is also referred to as a DSA (Digital Subtraction Angiography) image. The difference image is an example of a blood vessel image. Further, for example, the image processing circuit 26 reads out the image data collected by fluoroscopy from the storage circuit 25 and performs various image processes to generate a fluoroscopic image. The image processing circuit 26 can also perform noise reduction processing using an image processing filter such as a moving average (smoothing) filter, a Gaussian filter, or a median filter.

  The input circuit 22 includes a mouse, a keyboard, a trackball, a switch, a button, a joystick, and the like used for inputting various instructions and various settings, and receives instructions and settings from an operator. The display 23 is a monitor referred to by the operator, and displays an X-ray image under the control of the processing circuit 21. For example, the display 23 displays the fluoroscopic image as a moving image in real time. Further, for example, the display 23 displays a blood vessel image generated based on the blood vessel data so as to be superimposed on the fluoroscopic image. The X-ray image displayed on the display 23 will be described later. The display 23 displays a GUI (Graphical User Interface) for accepting an operator's instruction.

  The processing circuit 21 controls the overall operation of the X-ray diagnostic apparatus 100 by executing the acquisition function 211, the specifying function 212, and the display control function 213. For example, the processing circuit 21 reads a program corresponding to the collection function 211 from the storage circuit 25 and executes it, thereby collecting a plurality of X-ray images from the subject P into which the contrast agent has been injected over time. Further, for example, the processing circuit 21 reads out the program corresponding to the specific function 212 from the storage circuit 25 and executes it, so that the signal strength of the contrast agent for each unit region in the blood vessel region of the collected X-ray image is changed over time. Based on the transition, the blood vessel region in the blood flow direction is specified from a predetermined position in the blood vessel region. Here, the unit region is a region composed of one pixel in the blood vessel region of the X-ray image or a region composed of a plurality of pixels (pixel group) in the blood vessel region of the X-ray image. Hereinafter, a case where the unit area is an area composed of one pixel will be described. Hereinafter, the unit area is also simply referred to as a pixel. Further, for example, the processing circuit 21 reads out a program corresponding to the display control function 213 from the storage circuit 25 and executes it, thereby displaying a display image representing the specified blood vessel region in a display mode different from other blood vessel regions. To display. The details of the collection function 211, the identification function 212, and the display control function 213 by the processing circuit 21 will be described later. The collection function 211 in the first embodiment is an example of a collection unit in the claims. The specifying function 212 in the first embodiment is an example of a specifying unit in the claims. The display control function 213 in the first embodiment is an example of a display control unit in the claims.

  The overall configuration of the X-ray diagnostic apparatus 100 according to the first embodiment has been described above. Under such a configuration, the X-ray diagnostic apparatus 100 according to the first embodiment identifies a blood vessel region in the blood flow direction from a predetermined position, and represents the identified blood vessel region in a display mode different from other blood vessel regions. By presenting the display image to the operator, the efficiency of the procedure using the blood vessel image is improved. For example, the X-ray diagnostic apparatus 100 uses a blood vessel image by using a display image representing a blood vessel region specified in a blood flow direction from a predetermined position in a display mode different from other blood vessel regions as a blood vessel image of a road map. Improve the efficiency of the procedure.

  Here, the X-ray diagnostic apparatus 100 includes various road map functions for supporting device operations in blood vessels. For example, the X-ray diagnostic apparatus 100 can execute a perspective road map, a PI (Parametric Imaging) road map, and a 3D road map. Here, the perspective road map will be described with reference to FIG. FIG. 2 is a diagram for explaining a perspective road map. In the fluoroscopy roadmap, the difference between the image data that is filled with the contrast medium in the blood vessel and the image data that is collected without injecting the contrast medium is the difference. The difference image (contrast peak image) is displayed as a blood vessel image of the road map so as to overlap the fluoroscopic image. In the following description, an X-ray image displayed as a blood vessel image of a road map superimposed on a fluoroscopic image is also described as a mask image.

  The fluoroscopic image is an example of an X-ray image, and is an X-ray image with a smaller X-ray dose than a captured image such as a difference image. The fluoroscopic image is displayed as a moving image in real time, for example, and can indicate the current position of a device such as a catheter to the operator. On the other hand, in the fluoroscopic image, the shape of the blood vessel is not drawn except for the moment when the contrast medium is injected into the blood vessel. Thus, the road map function displays the mask image superimposed on the fluoroscopic image, and presents the shape of the blood vessel to the operator in addition to the current position of the device.

  The contrast peak image used for the mask image of the perspective road map is an image in which blood vessels and other tissues are distinguished as shown in FIG. For example, the operator advances the catheter along the blood vessel region (white region shown in FIG. 2). However, in the perspective road map based on the contrast peak image, as shown in FIG. 2, it is determined whether the blood vessels are actually connected in the portion where the blood vessels are overlapped, or whether the blood vessels that are not connected are simply overlapped. It may be difficult to do.

  Next, the PI road map will be described with reference to FIGS. 3A and 3B. 3A and 3B are diagrams for explaining the PI road map. In the PI roadmap, first, a plurality of image data are collected over time in a state in which the contrast medium is injected, and the acquired plurality of image data are respectively differentiated from the image data collected without injecting the contrast medium. A plurality of difference images are collected over time.

  Here, the signal strength of the contrast agent at each pixel of the difference image collected over time increases with the passage of time, and gradually decreases after reaching the maximum value. In the PI road map, a parameter value (feature value) is calculated for each pixel based on such a temporal transition of the contrast agent signal intensity. For example, “TTP (Time To Peak)” indicating the time required from the predetermined timing until the signal intensity reaches the maximum value is calculated as the parameter value. For example, as a parameter value, “TTA (Time To Arrival)” indicating a required time from a predetermined timing until the signal intensity reaches a value of a predetermined ratio of the maximum value is calculated. As the predetermined timing when calculating “TTP” and “TTA”, for example, the timing at which a contrast agent is injected, the timing at which a signal from the contrast agent first appears, or the like can be used.

  The parameter values in the PI roadmap are not limited to “TTP” and “TTA”, but “PH (Peak Height)” indicating the maximum value of the signal strength, and “AUC (Area Under Curve) indicating the accumulated amount of the signal strength. ) ”,“ AT (Arrival Time) ”indicating the time until the signal due to the contrast agent appears,“ Wash in ”indicating the time from when the signal due to the contrast agent appears until the signal intensity becomes maximum, and the signal intensity “Wash out” that indicates the time from when the maximum value of the contrast medium flows out, “Width” that indicates the half value width of the maximum value of the signal intensity, “MTT (Mean Transit Time)” It can also be used.

  Next, in the PI road map, as shown in FIGS. 3A and 3B, a color image in which each pixel of the blood vessel region included in the image is colored with a color corresponding to the calculated parameter value is generated. For example, in the color image, each pixel is colored according to the value of “TTP” calculated for each pixel. In the color image of the PI road map, as shown at positions R1 and R2 in FIG. 3A, if the colors of the intersecting blood vessels are different at the intersection where the blood vessels intersect, the unconnected blood vessels simply overlap. It can be determined that it is only visible.

  On the other hand, in the PI road map, as shown at position R3 in FIG. 3B, the colors of the intersecting blood vessels may be approximately the same at the intersection where the blood vessels intersect. In such a case, it is difficult to determine whether blood vessels are actually connected or whether the blood vessels that are not connected are simply overlapped and accidentally have the same color. That is, in the color image of the PI road map, it may be difficult to determine blood vessel travel at the intersection of blood vessels.

  Next, the 3D road map will be described. In the 3D road map, X-rays are irradiated from a plurality of directions to collect projection data, and a three-dimensional blood vessel image is reconstructed from the projection data. Then, by using such a three-dimensional blood vessel image as a mask image, it is possible to determine blood vessel running in a portion where blood vessels overlap. For example, even if there is an intersection where the blood vessels intersect when viewed from one direction, it can be determined whether the blood vessels at the intersection are actually connected when viewed from the other direction. However, in order to collect a three-dimensional blood vessel image, it is necessary to perform rotational imaging to collect projection data from a plurality of directions, to secure clearance between devices during rotational imaging, and to perform 3D image reconstruction processing. It takes time. Further, since imaging with a large dose is performed, an operator needs to leave the examination room at the time of imaging, and the exposure dose of the subject also increases. Therefore, it may be difficult to use the 3D roadmap in a clinical setting.

  Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment identifies a blood vessel region ahead from a predetermined position in the difference image, and displays a display image representing the identified blood vessel region in a display mode different from other blood vessel regions. By displaying, it is easy to grasp the blood vessel running and improve the efficiency of the procedure. Hereinafter, the process performed by the X-ray diagnostic apparatus 100 according to the first embodiment will be described in detail.

  First, the collection function 211 collects image data of the subject P in a state where no contrast agent is injected and image data (blood vessel data) of the subject P in a state where the contrast agent is injected. For example, the collection function 211 controls the high voltage generator 11 to supply a voltage to the X-ray tube 12 and irradiates the subject P in a state where no contrast agent is injected with X-rays. The collection function 211 detects X-rays transmitted through the subject P by the X-ray detector 16. Then, the collection function 211 controls the image data generation circuit 24 to obtain the image data of the subject P in a state where no contrast agent is injected from the electric signal converted from the X-rays by the X-ray detector 16. It is generated and stored in the storage circuit 25.

  Further, for example, the collection function 211 transmits an injection instruction to the injector 30 to inject a contrast medium into the subject P, irradiates the subject P with X-rays, and converts the X-rays transmitted through the subject P to X-rays. Detection is performed by the detector 16. The acquisition function 211 controls the image data generation circuit 24 to generate blood vessel data from the electrical signal converted from the X-rays by the X-ray detector 16 and store the blood vessel data in the storage circuit 25. Here, the collection function 211 generates a plurality of blood vessel data over time, and stores each in the storage circuit 25. Note that the order of collecting the image data and blood vessel data of the subject P in a state where no contrast agent is injected is arbitrary.

  Next, the collection function 211 collects a difference image using the image data and blood vessel data of the subject P in a state where no contrast agent is injected. For example, the collection function 211 controls the image processing circuit 26 to read the image data and the blood vessel data taken in a state where no contrast agent is injected from the storage circuit 25 and generate a difference image. Here, the collection function 211 collects a plurality of difference images over time by subtracting each of the plurality of blood vessel data collected over time from the image data collected without the contrast agent being injected. .

  Note that the difference image emphasizes the contrast agent flowing through the blood vessel region by erasing the background of bones and the like by subtracting the background from the blood vessel data in which the contrast agent in the blood vessel is imaged while the contrast agent is injected. X-ray image. Hereinafter, a case will be described in which a plurality of difference images are acquired as a plurality of X-ray images acquired over time based on X-rays transmitted through the subject P into which a contrast agent has been injected.

  Next, the specifying function 212 specifies a blood vessel region in the blood flow direction from a predetermined position in the blood vessel region based on the temporal transition of the contrast agent signal intensity for each pixel included in the blood vessel region of the plurality of difference images. To do. Hereinafter, the specification of the blood vessel region in the blood flow direction will be described in detail. The blood vessel region in the difference image is a region representing a blood vessel in the difference image. Since the difference image is generated based on the blood vessel data collected while injecting the contrast agent into the blood vessel, the specifying function 212 can specify the position of the contrast agent in the difference image as the blood vessel region. The blood flow direction is the direction in which blood flows (downstream direction).

  First, the specifying function 212 determines a predetermined position in the blood vessel region of the difference image. The predetermined position is the position of the starting point when the specifying function 212 specifies a blood vessel region in the blood flow direction. In other words, the predetermined position is an arbitrary upstream position in a blood vessel region in which the operator is interested, such as a blood vessel region in which the catheter is to be advanced.

  Here, the determination of the predetermined position will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of determination of a predetermined position according to the first embodiment. For example, the specifying function 212 receives a determination operation for determining a predetermined position from the operator who refers to the difference image displayed on the display 23 via the input circuit 22. For example, as illustrated in FIG. 4, the specific function 212 determines a position clicked by the operator as a predetermined position.

  Alternatively, the specific function 212 may be a case where a predetermined position is automatically determined. For example, the specifying function 212 first specifies the current position of the catheter tip based on the fluoroscopic images collected in real time. Next, the specifying function 212 determines a position corresponding to the current position of the catheter tip in the fluoroscopic image as a predetermined position in the difference image.

  Next, the specifying function 212 specifies a blood vessel region in the blood flow direction from a predetermined position. Here, the specification of the blood vessel region in the blood flow direction will be described with reference to FIGS. 5A, 5B, 5C, and 5D. 5A, 5B, 5C, and 5D are diagrams illustrating an example of specifying a blood vessel region in the blood flow direction according to the first embodiment. 5A, 5B, 5C, and 5D show some of the pixels that make up the difference image. The numerical values shown in the pixels of FIGS. 5A, 5B, 5C, and 5D indicate parameter values calculated for each pixel. A pixel P1 in FIG. 5A indicates a pixel included in a predetermined position. The characters “ON” shown in the pixels of FIGS. 5B and 5D indicate that the pixels are determined to be included in the blood vessel region in the blood flow direction. The character “OFF” shown in the pixel of FIG. 5D indicates that the pixel is determined not to be included in the blood vessel region in the blood flow direction.

  First, the specific function 212 calculates a parameter value for each pixel as shown in FIG. 5A. Here, the specific function 212 uses “TTP”, “TTA”, “PH”, “AUC”, “AT” as parameter values based on the temporal transition of the contrast agent signal intensity for each pixel of the difference image. , “Wash in”, “Wash out”, “Width”, “MTT”, and the like can be calculated. Hereinafter, a case where the specific function 212 calculates “TTP” as a parameter value will be described.

  Next, the specific function 212 calculates a difference of “TTP” between the pixel P1 included in the predetermined position and the pixel adjacent to the pixel P1. Here, the difference of “TTP” calculated by the specific function 212 may be a value obtained by subtracting “TTP” of the adjacent pixel from “TTP” of the pixel P1, or may be a pixel from “TTP” of the adjacent pixel. It may be a value obtained by subtracting “TTP” of P1, or may be an absolute value of the subtracted value.

  Hereinafter, a case where the specific function 212 calculates an absolute value of a value obtained by subtracting “TTP” of an adjacent pixel from “TTP” of the pixel P1 as a difference of “TTP” will be described. For example, the specific function 212 calculates the difference “0” between the “TTP” value “2” of the pixel P1 and the “TTP” value “2” of the adjacent pixel P2. For example, the specific function 212 calculates a difference “2” between the value “2” of “TTP” of the pixel P1 and the value “0” of “TTP” of the adjacent pixel P3. Similarly, the specific function 212 calculates the difference of “TTP” for the other six pixels adjacent to the pixel P1.

  Next, the specific function 212 determines a pixel in which the difference of “TTP” is equal to or less than a threshold among the pixels adjacent to the pixel P1 as a pixel included in the blood vessel region in the blood flow direction. For example, the specifying function 212 specifies a pixel included in a blood vessel region in the blood flow direction with a threshold value “1”. As an example, the difference in “TTP” between the pixel P1 and the adjacent pixel P2 is “0”, which is equal to or less than the threshold value “1”. The pixel P2 is determined as a pixel included in the blood vessel region in the blood flow direction. On the other hand, since the difference in “TTP” between the pixel P1 and the adjacent pixel P3 is “2” and is not equal to or less than the threshold value “1”, the specific function 212 sets the pixel P3 as shown in FIG. 5B. It is determined that the pixel is not included in the blood vessel region in the blood flow direction. Then, as illustrated in FIG. 5B, the specific function 212 determines that four pixels including the pixel P2 among the eight pixels adjacent to the pixel P1 are pixels included in the blood vessel region in the blood flow direction.

  Next, the specific function 212 calculates a difference of “TTP” between each of the four pixels determined to be included in the blood vessel region in the blood flow direction and the adjacent pixels. It is determined whether or not the pixel is included in the blood vessel region in the flow direction. For example, as illustrated in FIG. 5C, the specific function 212 calculates a difference of “TTP” between the pixel P2 determined to be included in the blood vessel region in the blood flow direction and the pixel adjacent to the pixel P2. Then, it is determined whether each of the adjacent pixels is a pixel included in the blood vessel region in the blood flow direction, depending on whether the calculated difference of “TTP” is equal to or less than the threshold value.

  Next, the specific function 212 calculates the difference in “TTP” between the pixel determined to be included in the blood vessel region in the blood flow direction among the pixels adjacent to the pixel P2, and the adjacent pixel. It is determined whether each of the pixels is a pixel included in a blood vessel region in the blood flow direction. Further, the specific function 212 calculates a difference of “TTP” between the pixel determined to be included in the blood vessel region in the blood flow direction and the adjacent pixel, and each of the adjacent pixels is a blood vessel region in the blood flow direction. The process of determining whether or not the pixel is included in the pixel is recursively performed on the pixel determined to be included in the blood vessel region in the blood flow direction.

  As described above, the specific function 212 calculates the difference of “TTP” between the pixel included in the blood vessel region in the blood flow direction and the adjacent pixel, and the difference of “TTP” among the adjacent pixels is equal to or less than the threshold value. The process of determining the pixel to be a pixel included in the blood vessel region in the blood flow direction is sequentially performed using the pixel P1 included in the predetermined position as the start point of the pixel included in the blood vessel region in the blood flow direction. Then, the specific function 212 determines the pixels included in the blood vessel region in the blood flow direction, thereby determining the blood vessel region in the blood flow direction (the pixel region indicating “ON” in the drawing) as shown in FIG. 5D. Identify.

  The specifying function 212 sequentially specifies pixels included in the blood vessel region in the blood flow direction from a predetermined position toward the downstream direction of the blood flow. For example, when comparing “TTP” between pixels, the specific function 212 determines that a pixel having a larger value of “TTP” is a downstream pixel. Then, the specific function 212 determines whether each pixel is located downstream from the predetermined position based on the value of “TTP”, and sequentially determines whether the difference of “TTP” between the pixels is equal to or less than a threshold value. By determining, a blood vessel region in the blood flow direction is specified from a predetermined position.

  Here, at the intersection where the blood vessels intersect, it may be difficult to specify the blood vessel region in the blood flow direction based only on “TTP”. Hereinafter, the specification of the blood vessel region in the blood flow direction at the intersection will be described with reference to FIGS. 6A, 6B, and 6C. 6A, 6B, and 6C are diagrams illustrating an example of specifying the blood vessel region in the blood flow direction at the intersection according to the first embodiment. 6A, 6B, and 6C show some of the pixels that make up the difference image. Moreover, the numerical value shown in the pixel of FIG. 6A, FIG. 6B, and FIG. 6C shows the parameter value calculated for every pixel.

  First, the specifying function 212 specifies pixels included in the blood vessel region in the blood flow direction in order from the pixel P4 shown in FIG. 6A toward the upper right in FIG. 6A. Here, the specifying function 212 specifies the pixel P5 shown in FIG. 6A as a pixel included in the blood vessel region in the blood flow direction, and then calculates the difference of “TTP” between the pixel P5 and the pixel adjacent to the pixel P5. It is calculated and it is determined whether or not each adjacent pixel is a pixel included in a blood vessel region in the blood flow direction.

  Here, the difference of “TTP” between the pixel P5 and the adjacent pixel P6 is “0”, and the difference of “TTP” between the pixel P5 and the adjacent pixel P7 is “1”, which is adjacent to the pixel P5. The difference of “TTP” from the pixel P8 is “1”. When the threshold value is “1”, the difference of “TTP” is less than or equal to the threshold value for all of the pixel P6, the pixel P7, and the pixel P8. However, the pixel P6, the pixel P7, and the pixel P8 adjacent to the pixel P5 are not blood vessels that are actually connected, but the blood vessels that are not connected are simply seen to overlap, and the value of “TTP” is a value close to chance. It may have become.

  Therefore, as shown in FIG. 6B, the specific function 212 calculates a vector (optical flow) representing the movement of the contrast agent in the blood vessel region, and based on the similarity of the optical flow between the pixels, Among the pixels, the pixels included in the blood vessel region in the blood flow direction are specified. For example, the specifying function 212 calculates the optical flow by connecting the position of the contrast agent in an arbitrary time frame and the position of the contrast agent in the next time frame among a plurality of difference images collected over time. The specifying function 212 may be a case where the optical flow is calculated for the entire difference image, or may be a case where the optical flow is calculated for each pixel near the intersection.

  Further, the specific function 212 determines the similarity of the optical flow between pixels. For example, the specific function 212 determines the similarity between the vector of the pixel P5 illustrated in FIG. 6B and the vectors of the pixel P6, the pixel P7, and the pixel P8. For example, the specifying function 212 calculates a difference between the vector of the pixel P5 and the vectors of the pixel P6, the pixel P7, and the pixel P8 for each of the magnitude and direction (angle) of the vector. Then, the specifying function 212 compares the calculated difference with a threshold set for each of the vector size and direction (angle), and based on whether the calculated difference is equal to or less than the threshold, It is determined whether or not the pixel is included in the blood vessel region in the blood flow direction.

  Among the pixels shown in FIG. 6B, for the pixel P6, the “TTP” value is close to the pixel P5, and the optical flow is similar. The pixel is determined to be included in the blood vessel region. On the other hand, regarding the pixel P7 and the pixel P8, although the value of “TTP” is close to that of the pixel P5, the optical flow is not similar, and therefore the specific function 212 is a pixel that is not included in the blood vessel region in the blood flow direction. Is determined. Thereby, the specifying function 212 specifies a blood vessel region in the blood flow direction at the intersection of the blood vessels, for example, as shown in a gray region in FIG. 6C.

  As described above, the specifying function 212 specifies a blood vessel region in the blood flow direction. Next, the display control function 213 causes the display 23 to display a display image representing the blood vessel region specified by the specifying function 212 in a display mode different from other blood vessel regions. Here, the display image representing the blood vessel region specified by the specific function 212 in a display mode different from other blood vessel regions is a blood vessel region specified by the specific function 212 other than the background region and the blood vessel region specified by the specific function 212. It is an image expressed so that it can be distinguished from the blood vessel region.

  For example, the display image is an image in which the blood vessel region specified by the specifying function 212 and another blood vessel region are expressed in different colors (hue, saturation, brightness, or a combination thereof). For example, the display control function 213 controls the image processing circuit 26, and is different from a pixel corresponding to the blood vessel region specified by the specifying function 212 and a pixel corresponding to another blood vessel region based on the difference image. By outputting the color, a display image expressing the blood vessel region specified by the specifying function 212 and other blood vessel regions in a distinguishable manner is generated. Here, an example of a display image displayed on the display 23 will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of a display image according to the first embodiment.

  For example, as shown in FIG. 7, the display control function 213 displays a display image in which the blood vessel region specified by the specifying function 212 (the blood vessel region ahead of a predetermined position) and other blood vessel regions are expressed in different colors. To display. Here, the display control function 213 displays the display image shown in FIG. 7 on the display 23 as a blood vessel image (mask image) of the road map. That is, the display control function 213 superimposes and displays the display image shown in FIG. 7 on the fluoroscopic image collected by the collection function 211 and displayed on the display 23 in real time.

  By performing the road map using the display image shown in FIG. 7, the display control function 213 can indicate to the operator which of the blood vessels on the image is the blood vessel ahead of the predetermined position. it can. For example, when the distal end of the catheter is located at a predetermined position in FIG. 7, the display control function 213 displays the current position of the catheter by the fluoroscopic image and displays the blood vessel through which the catheter can proceed by the display image. Can be shown.

  The display control function 213 can also display a display image updated in accordance with the movement of the distal end position of the catheter. For example, when the distal end position of the catheter is moved, the specifying function 212 sets a predetermined position again according to the moved distal end position of the catheter, and specifies a blood vessel region in the blood flow direction from the set predetermined position. . Then, the display control function 213 masks and displays the display image in which the previous blood vessel region is emphasized from the distal end position of the catheter after movement as a fluoroscopic image.

  Here, the display control function 213 displays, for example, a display image that displays only the blood vessel region in the blood flow direction from the latest predetermined position as the display image in which the blood vessel region ahead from the tip position of the moved catheter is emphasized. indicate. For example, the display control function 213 displays a display image in which each branch target blood vessel is emphasized before the catheter tip passes through the branch point of the blood vessel (the intersection of the blood vessels that are actually connected). On the other hand, the display control function 213 displays a display image in which only the blood vessel selected as the catheter destination is emphasized after the catheter tip passes the branch point.

  Alternatively, the display control function 213 overwrites the blood vessel region in the blood flow direction with a different color every time a predetermined position is changed, for example, as a display image in which the previous blood vessel region is emphasized from the tip position of the catheter after movement. Display the displayed image. For example, the display control function 213 displays a display image in which each branch destination blood vessel is expressed in the same color before the catheter tip passes through the branch point. On the other hand, the display control function 213 displays a display image in which the blood vessel selected as the catheter destination and other blood vessels are expressed in different colors after the catheter tip passes the branch point. According to such a display image, the display control function 213 can distinguish between a blood vessel that has already passed through the catheter or a blood vessel that has not been selected as a blood vessel for advancing the catheter, and a blood vessel from which the catheter can proceed. To.

  The display image is not limited to an image in which the blood vessel region specified by the specifying function 212 and other blood vessel regions are expressed in different colors. For example, the display image is an image representing only the blood vessel region specified by the specifying function 212 or only the blood vessel region and the background region specified by the specifying function 212. For example, the display image is a color image obtained by coloring the blood vessel region specified by the specifying function 212 with a color corresponding to the parameter value calculated for each pixel of the blood vessel region.

  As described above, the display control function 213 displays the display image on the display 23 as a blood vessel image of the road map. However, the embodiment is not limited to this. For example, the display image can be used not as a blood vessel image of a road map but as a preoperative diagnostic image. Hereinafter, this point will be described with reference to FIGS. 8A and 8B. 8A and 8B are diagrams illustrating an example of a display image according to the first embodiment.

  FIG. 8A shows a difference image collected for the head of the subject P. FIG. First, the specifying function 212 receives a determination operation for determining a predetermined position from the operator who refers to the difference image displayed on the display 23 via the input circuit 22. Next, the specifying function 212 specifies a blood vessel region ahead from a predetermined position. Then, as shown in FIG. 8B, the display control function 213 causes the display 23 to display a display image in which the blood vessel region specified by the specifying function 212 is emphasized.

  In the display image shown in FIG. 8B, the blood vessel region downstream from the blood vessel region designated as the predetermined position in the entire difference image collected for the head of the subject P is displayed with emphasis. That is, the blood vessel highlighted in the display image shown in FIG. 8B indicates a blood vessel that can be reached when the catheter is inserted from a predetermined position. Therefore, the display control function 213 indicates whether the catheter can be inserted from a predetermined position to reach the target position by presenting the display image shown in FIG. It can support the determination of whether the position can be reached.

  Although the case where the predetermined position is one position has been described so far, the embodiment is not limited to this. Hereinafter, this point will be described with reference to FIGS. 9A and 9B. 9A and 9B are diagrams illustrating an example of a display image according to the first embodiment. For example, as illustrated in FIG. 9A, the specifying function 212 receives a determination operation for determining a plurality of predetermined positions from the operator who refers to the difference image displayed on the display 23 via the input circuit 22. Next, the specifying function 212 specifies a previous blood vessel region from each of a plurality of predetermined positions.

  Then, the display control function 213 causes the display 23 to display a display image in which the blood vessel region specified for each of the predetermined positions by the specifying function 212 is emphasized. For example, as shown in FIG. 9B, the display control function 213 displays a display image in which blood vessel regions specified for each predetermined position are expressed in different colors. Therefore, the display control function 213 can efficiently show the blood vessel region that can be reached when the catheter is inserted from each predetermined position by presenting the display image shown in FIG. 9B to the operator.

  Next, an example of a processing procedure performed by the X-ray diagnostic apparatus 100 will be described with reference to FIG. FIG. 10 is a flowchart for explaining a series of processing flow of the X-ray diagnostic apparatus 100 according to the first embodiment. Step S 101, step S 102 and step S 107 are steps corresponding to the collection function 211. Step S103, step S104, and step S105 are steps corresponding to the specific function 212. Step S <b> 106 is a step corresponding to the display control function 213.

  First, the processing circuit 21 determines whether or not an inspection start command has been accepted (step S101), and enters a standby state when no inspection start command is accepted (No in step S101). On the other hand, when receiving the examination start command (Yes at Step S101), the processing circuit 21 collects a plurality of X-ray images over time based on the X-rays transmitted through the subject P into which the contrast agent has been injected. (Step S102). Note that the X-ray image collected in step S102 is, for example, a difference image.

  Next, the processing circuit 21 calculates “TTP” for each pixel based on the temporal transition of the signal strength of the contrast agent for each pixel included in the blood vessel region of the X-ray image (step S103). Further, the processing circuit 21 acquires a predetermined position in the blood vessel region of the X-ray image (step S104). Next, the processing circuit 21 specifies a blood vessel region in the blood flow direction from a predetermined position based on “TTP” calculated for each pixel (step S105).

  Then, the processing circuit 21 generates a display image representing the identified blood vessel region in a display mode different from other blood vessel regions, and displays the display image on the display 23 (step S106). Here, the processing circuit 21 determines whether or not an inspection end command has been received (step S107), and enters a standby state when no inspection end command is received (No in step S107). On the other hand, when the processing circuit 21 receives an inspection end command (Yes in step S107), the processing circuit 21 ends the processing.

  In step S103, the processing circuit 21 may calculate “TTP” as a parameter value, or may calculate another parameter value such as “TTA” or “PH”. In addition, the acquisition of the predetermined position in step S104 may be performed before step S103. In addition, the display image displayed on the display 23 in step S106 may be displayed as a mask image displayed superimposed on the fluoroscopic image, or may be displayed without being superimposed on the fluoroscopic image. It may be.

  As described above, according to the first embodiment, the collection function 211 collects a plurality of X-ray images over time based on X-rays transmitted through the subject P into which a contrast agent has been injected. The specifying function 212 specifies a blood vessel region in the blood flow direction from a predetermined position in the blood vessel region based on the temporal transition of the contrast agent signal intensity for each pixel included in the blood vessel regions of the plurality of X-ray images. The display control function 213 displays a display image representing the blood vessel region specified by the specifying function 212 in a display mode different from other blood vessel regions. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can improve the efficiency of the procedure by presenting the blood vessel region ahead from a predetermined position to the operator and facilitating the grasp of the blood vessel running. it can.

  Further, according to the first embodiment, the specifying function 212 specifies the blood vessel region in the blood flow direction at the intersection based on the optical flow even when there is an intersection where the blood vessels intersect. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can appropriately specify the blood vessel region in the blood flow direction and present the display image to the operator even for the complicated blood vessel region including the intersection. .

  Further, according to the first embodiment, the display control function 213 displays a display image as a blood vessel image of the road map. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can indicate to the operator the blood vessel region in which the catheter inserted into the blood vessel can be advanced from the current position, and improve the efficiency of the procedure. it can.

  Further, according to the first embodiment, the display control function 213 facilitates grasping of blood vessel travel while performing a road map using two-dimensional blood vessel data. Therefore, the X-ray diagnostic apparatus 100 according to the first embodiment can generate a mask image more quickly than the three-dimensional road map, and can perform a road map in which the exposure dose of the subject P is reduced.

(Second Embodiment)
In the first embodiment described above, a parameter value such as “TTP” is calculated based on the temporal transition of the signal strength of the contrast agent for each pixel included in the blood vessel region of the X-ray image, and based on the parameter value. The case where the blood vessel region in the blood flow direction is specified from the predetermined position has been described. On the other hand, in the second embodiment, the blood vessel region in the blood flow direction from a predetermined position is based on the similarity of the temporal transition of the signal strength of the contrast agent for each pixel included in the blood vessel region of the X-ray image. The case of specifying the will be described.

  The X-ray diagnostic apparatus according to the second embodiment has the same configuration as that of the X-ray diagnostic apparatus according to the first embodiment shown in FIG. 1, and a part of the processing by the specifying function 212 is different. Therefore, the same reference numerals as those in FIG. 1 are given to the components having the same configurations as those described in the first embodiment, and the description thereof is omitted.

  First, the collection function 211 collects a plurality of X-ray images over time based on X-rays transmitted through the subject P into which a contrast agent has been injected. The collection function 211 collects, for example, a plurality of difference images over time as a plurality of X-ray images. Further, the specifying function 212 acquires a predetermined position in the blood vessel region of the difference image. Next, the specific function 212 determines the similarity of the temporal transition of the contrast agent signal intensity between the pixel included in the blood vessel region in the blood flow direction and the adjacent pixel.

  Here, the temporal transition of the signal strength of the contrast agent is expressed by, for example, a time density curve (TDC). TDC is a graph in which time is plotted on the horizontal axis and the signal strength of the contrast agent is plotted on the vertical axis, and the temporal transition of the signal strength of the contrast agent is plotted for each pixel. For example, the signal strength of the TDC gradually increases as the contrast agent flows into the pixel from the signal strength of the pixel in the absence of the contrast agent. A state in which the signal intensity of the pixel in the state where the intensity is reduced and the contrast agent is absent again is shown. Further, the specific function 212 calculates the TDC for each pixel.

  For example, for the TDC of each pixel, the specific function 212 determines the TDC position (the time when the signal due to the contrast agent appears, the time when the signal due to the contrast agent reaches the maximum value, the time when the signal due to the contrast agent disappears, etc.) Height (maximum value of signal by contrast agent, integral value of signal by contrast agent, etc.), TDC shape (signal strength by contrast agent at any time from the appearance of the signal by contrast agent to disappearance, graph Various evaluation values such as the slope of the Next, the specifying function 212 compares the evaluation values calculated for the TDC of each pixel between the pixels, and, for example, based on whether or not the difference between the evaluation values between the pixels exceeds a threshold, the signal strength of the contrast agent Determine the similarity of transitions over time.

  When each of the pixels for determining the similarity of TDC is included in a blood vessel that is actually connected, a similar evaluation value is calculated for any of the position, height, and shape of the TDC. On the other hand, when each of the pixels for determining the similarity of TDC is included in a separate blood vessel that is not actually connected, a dissimilar evaluation value is calculated for the position, height, and shape of the TDC. Therefore, the specific function 212 includes processing for determining a pixel having a similar TDC among adjacent pixels as a pixel included in the blood vessel region in the blood flow direction, and includes a pixel included in the predetermined position in the blood vessel region in the blood flow direction. The blood vessel region in the direction of blood flow can be specified by sequentially performing as the starting point of the pixel to be recorded.

  Note that it may be difficult to specify a blood vessel region in the blood flow direction based only on the TDC similarity at the intersection where the blood vessels intersect. For example, each pixel at the intersection of the blood vessel region in the difference image is not a blood vessel that is actually connected, but a blood vessel that is not connected is simply seen overlapping, and the TDC of each pixel at the intersection is accidentally similar. There may be. In this case, the specifying function 212 calculates the optical flow of each pixel, and specifies the pixel included in the blood vessel region in the blood flow direction among the respective pixels near the intersection based on the similarity of the optical flow between the pixels. To do.

  Next, the display control function 213 causes the display 23 to display a display image representing the blood vessel region specified by the specifying function 212 in a display mode different from other blood vessel regions. For example, the display control function 213 causes the display image to be displayed on the display 23 as a blood vessel image of a road map, superimposed on the fluoroscopic image. Alternatively, the display control function 213 displays the display image on the display 23 without superimposing the display image on the fluoroscopic image.

  As described above, the specifying function 212 according to the second embodiment is based on the similarity between pixels of the temporal transition of the contrast agent signal intensity for each pixel included in the blood vessel region of the difference image. A blood vessel region in the flow direction is specified. Therefore, the X-ray diagnostic apparatus 100 according to the second embodiment comprehensively evaluates the temporal transition of the signal intensity at each pixel, identifies the blood vessel region in the blood flow direction, and operates an appropriate display image. Can be presented to the person.

(Third embodiment)
Although the first and second embodiments have been described so far, the present invention may be implemented in various different forms other than the above-described embodiments.

  In the above-described embodiment, when it is difficult to specify the blood vessel region in the blood flow direction based on the temporal transition of the parameter value for each pixel or the signal intensity for each pixel at the intersection where the blood vessels intersect, The optical flow is calculated, and the pixel included in the blood vessel region in the blood flow direction is specified from the respective pixels near the intersection based on the similarity of the optical flow between the pixels. However, the embodiment is not limited to this.

  For example, the specifying function 212 specifies pixels included in the blood vessel region in the blood flow direction among the respective pixels near the intersection by performing fluid analysis (Computational Fluid Dynamics: CFD) based on a plurality of difference images. For example, the specifying function 212 first determines the blood flow state (speed of blood flow or the like) at each position in the blood vessel region of the difference image from the position of the contrast agent depicted in each of the plurality of difference images by CFD. Direction, flow rate, pressure, etc.).

  Here, at the intersection, there are a blood vessel that allows blood to flow into the intersection and a blood vessel that causes blood to flow out from the intersection. For example, in a cross-shaped intersection, four blood vessels will extend from the intersection, but at least one of the four blood vessels is a blood vessel that allows blood to flow into the intersection, At least one blood vessel is a blood vessel that causes blood to flow out from the intersection. Here, when blood vessels that are not actually connected are simply seen to overlap, there are two blood vessels that allow blood to flow into the intersection and two blood vessels that allow blood to flow out of the intersection.

  Therefore, when the specific function 212 can determine that there is one blood vessel that allows blood to flow into the intersection and three blood vessels that allow blood to flow out of the intersection based on the direction of blood flow obtained by CFD, or When it can be determined that there are three blood vessels that allow blood to flow into the intersection and one blood vessel that allows blood to flow out of the intersection, it is determined that the blood vessels are actually connected to each other.

  In addition, when there are two blood vessels that allow blood to flow into the intersection and two blood vessels that cause blood to flow out of the intersection, the specific function 212 compares the flow rates of the four blood vessels. Here, when there are two pairs of blood vessels that have the same flow rate between the blood vessel that flows blood into the intersection and the blood vessel that flows blood out of the intersection, the specific function 212 determines that this intersection is actually Judge that unconnected blood vessels are simply visible. In addition, there is no pair of blood vessels having the same flow rate between the blood vessel that causes blood to flow into the intersection and the blood vessel that causes blood to flow out of the intersection, and the sum of the flow rates of the two blood vessels that allow blood to flow into the intersection. When the sum of the flow rates of the two blood vessels that allow blood to flow out from the intersection is only the same, the specific function 212 determines that the intersection is actually connected to the blood vessel.

  In addition, when it is difficult to specify the blood vessel region in the blood flow direction of the intersection based on the parameter value for each pixel, the specifying function 212 is based on the transition of the signal intensity for each pixel in the vicinity of the intersection. Among these pixels, pixels included in the blood vessel region in the blood flow direction can be specified. For example, the specifying function 212 compares the TDC of each pixel in the vicinity of the intersection with each other, specifies a pixel with a similar TDC as a pixel included in a blood vessel region in the blood flow direction, and determines blood flow in the intersection. Identify the vascular region in the direction.

  In the above-described embodiment, the case where parameter values, TDC, and the like are compared between adjacent pixels has been described. However, the embodiment is not limited to this. For example, for the parameter value calculated for each pixel, the specifying function 212 calculates the average value of the parameter value for each fixed range (for example, every 25 pixels of “5 × 5”), It is determined whether or not the difference from the parameter value of each pixel is equal to or less than the threshold value, and pixels whose difference from the average value is equal to or less than the threshold value are determined to be included in the blood vessel region in the blood flow direction. Here, for example, when there is only one pixel that does not fall below the threshold value, this pixel is considered to be noise generated in the X-ray image, so the specific function 212 determines that the pixel is included in the blood vessel region in the blood flow direction. To do. On the other hand, if there are a plurality of pixels that do not fall below the threshold, the specifying function 212 determines that these pixels are not included in the blood vessel region in the blood flow direction.

  That is, the specifying function 212 can specify a blood vessel region in the blood flow direction based on not only the parameter values of adjacent pixels but also the parameter values of neighboring pixels. In other words, the specifying function 212 can specify the blood vessel region in the blood flow direction based on the continuity of the parameter values. Similarly, the specifying function 212 can also specify a blood vessel region in the blood flow direction based on the TDC of each pixel and the continuity of the optical flow.

  In the above-described embodiment, the case has been described in which the collection function 211 collects a plurality of difference images over time based on X-rays transmitted through the subject P into which a contrast agent has been injected. It is not limited to this. For example, the acquisition function 211 controls the image processing circuit 26 to generate a plurality of X-ray images from image data (blood vessel data) acquired in a state where a contrast agent is injected. In other words, the collection function 211 collects a plurality of X-ray images that are not difference images over time. The specific function 212 then selects a blood vessel in a blood flow direction from a predetermined position in the blood vessel region based on the temporal transition of the signal strength of the contrast agent for each pixel included in the blood vessel region of the plurality of X-ray images. The region is specified, and the display control function 213 causes the display 23 to display a display image representing the specified blood vessel region in a display mode different from other blood vessel regions.

  In the above-described embodiment, the predetermined position is described as corresponding to one pixel in the difference image, but the embodiment is not limited to this. For example, a plurality of pixels may be included in a predetermined position. In this case, the specifying function 212 sets the blood vessel region in the blood flow direction using each of the plurality of pixels included in the predetermined position as a starting point or an arbitrary pixel among the plurality of pixels included in the predetermined position as the starting point. By sequentially specifying the included pixels, the blood vessel region in the blood flow direction can be specified.

  In the above-described embodiment, the case where the unit region is a region including one pixel has been described. However, the unit region may be a region including a plurality of pixels. For example, the specific function 212 calculates “TTP” for each unit region including four pixels. For example, the specifying function 212 calculates the time required until the sum of the signal intensities of the four pixels in the unit region reaches a maximum value from a predetermined timing as “TTP”. Then, the specifying function 212 can specify the blood vessel region in the blood flow direction by sequentially specifying the unit regions included in the blood vessel region in the blood flow direction based on “TTP” calculated for each unit region. . Furthermore, the display control function 213 sets the value of “TTP” calculated for each unit region as the value of “TTP” of each pixel included in the unit region, thereby determining the blood vessel region specified by the specifying function 212 for each pixel. It is also possible to display a display image colored with a color corresponding to the value of “TTP”.

  In the above-described embodiment, the case where the X-ray diagnostic apparatus performs each process has been described as an example. However, the embodiment is not limited thereto, and for example, the above-described process is performed in the image processing apparatus. It may be the case. In such a case, the image processing apparatus includes a processing circuit having the specific function 212 and the display control function 213 described above. The image processing apparatus also includes an interface for acquiring a plurality of X-ray images collected over time based on X-rays transmitted through the subject P into which a contrast medium has been injected.

  Each component of each device according to the first to third embodiments is functionally conceptual and does not necessarily need to be physically configured as illustrated. That is, the specific form of distribution / integration of each device is not limited to the one shown in the figure, and all or a part of the distribution / integration may be functionally or physically distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or a part of each processing function performed in each device may be realized by a CPU and a program that is analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  The control methods described in the first to third embodiments can be realized by executing a control program prepared in advance on a computer such as a personal computer or a workstation. This control program can be distributed via a network such as the Internet. The control program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

  According to at least one embodiment described above, the efficiency of a procedure using a blood vessel image can be improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

100 X-ray Diagnostic Equipment 21 Processing Circuit 211 Collection Function 212 Specific Function 213 Display Control Function

Claims (13)

A collection unit that collects a plurality of X-ray images over time based on X-rays transmitted through a subject into which a contrast medium has been injected;
A blood vessel region in a blood flow direction from a predetermined position in the blood vessel region based on a temporal transition of the signal strength of the contrast agent for each unit region composed of one or a plurality of pixels in the blood vessel region of the plurality of X-ray images. A specific part to identify;
A display control unit that displays a display image representing the blood vessel region specified by the specifying unit in a display mode different from a blood vessel region other than the blood vessel region;
An X-ray diagnostic apparatus comprising:   The specifying unit calculates a feature amount related to the flow of the contrast agent for each unit region based on the transition of the signal intensity with time, and based on the continuity of the calculated feature amount, The X-ray diagnostic apparatus according to claim 1, wherein a blood vessel region is specified.   The specifying unit calculates a difference in the feature amount between the unit region included in the blood vessel region in the blood flow direction and the adjacent unit region, and the difference in the feature amount among the adjacent unit regions is calculated. The unit area included in the blood vessel region in the blood flow direction is the process of determining the unit region included in the blood vessel region in the blood flow direction as the unit region included in the blood vessel direction in the blood flow direction. The X-ray diagnostic apparatus according to claim 2, wherein the blood vessel region in the blood flow direction is specified by sequentially performing the region as a starting point.   The feature amount is a required time from a predetermined timing until the signal intensity reaches a maximum value, or a required time from the predetermined timing until the signal intensity reaches a value of a predetermined ratio of the maximum value. Item 4. The X-ray diagnostic apparatus according to Item 2 or 3.   The X-ray diagnostic apparatus according to claim 1, wherein the specifying unit specifies a blood vessel region in the blood flow direction based on a similarity between the unit regions of the signal intensity over time.   The specifying unit calculates a vector representing the movement of the contrast agent for each of the unit regions of the blood vessel region by comparing the plurality of X-ray images with each other, and the similarity of the vectors between the unit regions 6. The X-ray according to claim 2, wherein the unit region included in the blood vessel region in the blood flow direction among the unit regions in the vicinity of the intersection where the blood vessels intersect is specified based on the sex. Diagnostic device.   The specifying unit specifies the unit region included in the blood vessel region in the blood flow direction among the unit regions in the vicinity of the intersecting portion where blood vessels intersect by performing fluid analysis based on the plurality of X-ray images. The X-ray diagnostic apparatus as described in any one of Claims 2 thru | or 5.   The specifying unit is included in the blood vessel region in the blood flow direction among the unit regions in the vicinity of a crossing portion where blood vessels intersect based on the similarity between the unit regions of the signal intensity over time. The X-ray diagnostic apparatus according to claim 2, wherein a unit region is specified.   The X-ray according to any one of claims 1 to 8, wherein the display control unit displays the display image in which the blood vessel region specified by the specifying unit is expressed in a color different from a blood vessel region other than the blood vessel region. Diagnostic device. The specifying unit specifies a blood vessel region in the blood flow direction for each of the plurality of predetermined positions,
The said display control part displays the said display image which represented the blood vessel area | region which the said specific part specified about each of several said predetermined positions with a mutually different color. X-ray diagnostic equipment.   The X-ray diagnosis apparatus according to claim 1, wherein the display control unit displays the display image as a blood vessel image of a road map.   The specifying unit uses the tip position of the device included in the plurality of X-ray images or the position received from the operator in the blood vessel region of the plurality of X-ray images as the predetermined position, and the blood vessel in the blood flow direction The X-ray diagnostic apparatus according to any one of claims 1 to 11, wherein a region is specified. Transition with time of the signal strength of the contrast medium for each unit region composed of one or a plurality of pixels in a blood vessel region of a plurality of X-ray images collected based on X-rays transmitted through a subject into which a contrast agent has been injected Based on the specific part for specifying the blood vessel region in the blood flow direction from a predetermined position in the blood vessel region,
A display control unit that displays a display image representing the blood vessel region specified by the specifying unit in a display mode different from a blood vessel region other than the blood vessel region;
An image processing apparatus comprising: